View Full Version : The Myth of MH being hotter than T5s.
Tang Salad
02/25/2008, 11:59 PM
Like many people I always thought that MHs were hotter than T5s, with all other factors (lumens, power consumption) being equal. But apparently, this is not the case.
The reason MHs seem hotter is just that they are a point source of heat, whereas T5s have (the same) heat spread out over a greater length.
If you take a 250 MH and ballast and put it in a box, and 250 watts of T5s and ballasts and put them in a box, the temperatures of the two boxes will rise at equal rates and reach equal temperatures.
It's another case of the laws of thermodynamics and conservation of energy at work. All light gets converted into heat; ergo equal light=equal heat. (Photosynthesis and other photo-chemical conversions aside...)
Anyway, this is new to me, so just thought I'd share. :)
Tang Salad
02/26/2008, 12:01 AM
And I'd like to thank SimilanRocks for pointing me to this thread (http://forums.gardenweb.com/forums/load/lights/msg0318383023578.html?13) which explained this to me.
Tang Salad
02/26/2008, 09:18 AM
Wow. If I'd started a thread saying "My MHs are too hot" I would have received a dozen replies by now. People would have posted:
"Yeah man, get T5s instead. MHs can cook a tank."
"Metal halides run really hot."
"Ditch the MHs for T5s, you'll save on electricity and won't need a chiller."
Sometime I just don't get RC... :lol:
BeanAnimal
02/26/2008, 09:30 AM
If you take a 250 MH and ballast and put it in a box, and 250 watts of T5s and ballasts and put them in a box, the temperatures of the two boxes will rise at equal rates and reach equal temperatures. That is pretty much the definition of a Watt and exactly why we can label things with Watts and make meaningful comparisons about the energy they consume (or the heat they gice off).
A 100 watt lighbult heats the room just as much as a 100 watt heater or a 100 watt speaker. Watts are watts :)
ElDiabloPollo
02/26/2008, 09:32 AM
I guess the question, or the thing missing is a ratio or Par to Watts and how it relates to heat.
Just because you have 250 watts of light, does not mean the corals can use it.
Tang Salad
02/26/2008, 09:34 AM
Hey BeanAnimal, long time no see.
Yep, a watt is a watt is a watt. What surprises me is that it's still "common knowledge" here on RC that T5s are much cooler than MHs. I guess it was my mistake to assume that common knowledge is correct knowledge.
luke33
02/26/2008, 09:38 AM
The myth is t5's are cooler because the heat is distributed accross the whole bulb so they seem cooler, but yes a watt is a watt. Now your thread title is misleading a bit. A mh is much much hotter than a t5 if you touch each one with your finger ; )
BeanAnimal
02/26/2008, 09:38 AM
MH may heat the water more via radiation than a T5, but from the standpoint of the "room" they are both the same.
Tang Salad
02/26/2008, 09:40 AM
<a href=showthread.php?s=&postid=11945797#post11945797 target=_blank>Originally posted</a> by BeanAnimal
MH may heat the water more via radiation than a T5, but from the standpoint of the "room" they are both the same.
Which radiation are you speaking of? Visible spectrum, or other?
BeanAnimal
02/26/2008, 09:41 AM
ElDiabloPollo:
Do you prefer to be called Evil Chicken or The Chicken Devil?
BIOCUBE UNIT
02/26/2008, 09:42 AM
I guess the next question is which light source produces more intense lighting? I would think that MH would and you just can't beat the shimmer that they produce.
BeanAnimal
02/26/2008, 09:42 AM
<a href=showthread.php?s=&postid=11945810#post11945810 target=_blank>Originally posted</a> by Tang Salad
Which radiation are you speaking of? Visible spectrum, or other?
ANY Radiation can impart heat directly into the water, different wavelengths will penetrate differently and may heat the rock or the livestock directly instead of the water. Those objects will of course give up their heat to the water :)
Tang Salad
02/26/2008, 09:43 AM
Six of one, half a dozen...
BeanAnimal
02/26/2008, 09:45 AM
<a href=showthread.php?s=&postid=11945829#post11945829 target=_blank>Originally posted</a> by Tang Salad
Six of one, half a dozen...
Well not really. I think you will find that the MH produces more wavelengths that can directly heat the tank and its contents via radiation. I could be wrong and have never taken the time to look into the exact differences between the two.
Tang Salad
02/26/2008, 09:47 AM
So, back to the original issue. Two tanks, both have an equal amount of light. One uses T5s to get that light, one uses MHs. Both will have an equal amount of heat imparted to the water from the light.
Therefore, T5s are not any cooler than MHs.
wet reefer
02/26/2008, 09:47 AM
A 100 watt lighbult heats the room just as much as a 100 watt heater or a 100 watt speaker. Watts are watts
True, but a 100 watt speaker is rated UP TO 100 watts. That doesn't mean they use 100 watts all the time. A 100 watt light bulb uses 100 watts all the time.
Tang Salad's is correct if "the box" was the exact same size. If one box is twice the size of the other then you have more area for the heat to dissipate into the area around it. The more area around it, the less it will heat the tank. But it will still create the same amount of heat overall.
BeanAnimal
02/26/2008, 10:05 AM
<a href=showthread.php?s=&postid=11945884#post11945884 target=_blank>Originally posted</a> by wet reefer True, but a 100 watt speaker is rated UP TO 100 watts. That doesn't mean they use 100 watts all the time. A 100 watt light bulb uses 100 watts all the time. [/b] Let me rephrase...
A speaker driven at 100 watts will put the same heat into the room as a 100 watt light bulb :) The average 100 watt amp and speaker may use 1 watt on average, most of the time :)
BeanAnimal
02/26/2008, 10:09 AM
<a href=showthread.php?s=&postid=11945878#post11945878 target=_blank>Originally posted</a> by Tang Salad
So, back to the original issue. Two tanks, both have an equal amount of light. One uses T5s to get that light, one uses MHs. Both will have an equal amount of heat imparted to the water from the light.
Therefore, T5s are not any cooler than MHs.
No, only if both bulbs radiated the same amount of energy in all spectrums :) Otherwise, one unit will give more heat up to the room via convection and conduction.
That is why 250W worth of LEDs heat the water LESS then 250W worth of MH, even if both are putting out the same PAR :) The MH is NOT putting out the same overall spectrum. Much of its heat is conducted to the heatsink at the back of the die and convected to the room. Watts are Watts, but where they end up can vary depending on what slice of time (and where you look).
wet reefer
02/26/2008, 10:09 AM
Now if we could just figure out a way to connect a speaker to our tanks.........
OranguTang
02/26/2008, 10:13 AM
<a href=showthread.php?s=&postid=11945878#post11945878 target=_blank>Originally posted</a> by Tang Salad
So, back to the original issue. Two tanks, both have an equal amount of light. One uses T5s to get that light, one uses MHs. Both will have an equal amount of heat imparted to the water from the light.
Therefore, T5s are not any cooler than MHs.
I have had this experience first hand.
Originally I had a 60g long with 4x54w T5HO OD on an IC660 ~350w. Now I have a 60g cube with a 400w halide. Constantly battled high temps with the T5 setup, had to install fans in the hood etc etc. I am sure the same would be true for the halide had I an enclosed hood. I now have an open top tank and a pendant with no heat problems and PAR goodness.
Tang Salad
02/26/2008, 10:17 AM
<a href=showthread.php?s=&postid=11946048#post11946048 target=_blank>Originally posted</a> by BeanAnimal
No, only if both bulbs radiated the same amount of energy in all spectrums :) Otherwise, one unit will give more heat up to the room via convection and conduction.
So T5s give more heat energy to the room, while MHs give more heat energy to the tank?
wet reefer
02/26/2008, 10:26 AM
I would think a 400 watt MH pendant, which allows a better free flow of air up and away from the tank would not heat a tank as much as 400 watts of T5 covering a tank. There are so many variables I don't think you could say one will heat a tank more than the other across the board.
Logzor
02/26/2008, 11:04 AM
More air can pass across a T5 bulb than can a MH bulb in a given amount of time. If air can absorb or move heat then T5 are, effectively, putting less heat into the tank.
This makes sense, as stated before, because a T5 bulb has a larger surface area. Simple as that. Agreed, a watt is a watt.
Iostream
02/26/2008, 11:21 AM
One thing that has not been discussed is ballast efficiency. What is the actual draw to power that 250W bulb? And this can make a large difference as the ballast itself is putting heat into the room (or tank depending on ballast location).
BeanAnimal
02/26/2008, 11:23 AM
<a href=showthread.php?s=&postid=11946115#post11946115 target=_blank>Originally posted</a> by Tang Salad
So T5s give more heat energy to the room, while MHs give more heat energy to the tank?
That is a tricky question with a lot of variables.
No matter what the heat ends up in the room. The MH has a greater chance of radiating heat into the tank. However, the T5s do more to prevent air movement and therefore may trap heat above the water where it can be absorbed into the tank.
Each setup is different. But if we are talking direct heating of the water due to radiation, then the MH is likely the technology that will win.
BeanAnimal
02/26/2008, 11:26 AM
<a href=showthread.php?s=&postid=11946657#post11946657 target=_blank>Originally posted</a> by Iostream
One thing that has not been discussed is ballast efficiency. What is the actual draw to power that 250W bulb? And this can make a large difference as the ballast itself is putting heat into the room (or tank depending on ballast location).
We re not talking about the label on the bulbs or ballast when we are talking about "a Watt is a Watt", we are talking about the total power consumed from the wall receptacle :)
It it consumes 321 watts from the wall, then it WILL put 321 watts worth of heat into the room. Take two devices that draw exactly 50 Watts, say a heater and a pump. Both will HEAT a closed bucket of water to the same temperature at the same rate.
The pump is efficient at moving water but not efficient at making light. The light is not efficient at moving water but in compression is efficient at making light.
ErikS
02/26/2008, 11:27 AM
<a href=showthread.php?s=&postid=11943889#post11943889 target=_blank>Originally posted</a> by Tang Salad
If you take a 250 MH and ballast and put it in a box, and 250 watts of T5s and ballasts and put them in a box, the temperatures of the two boxes will rise at equal rates and reach equal temperatures.
Yeah........except one little "glitch", from most every test I've seen......
250w T5 > 250w MH when comparing PAR
................so if you have to use more watts to get the same "output" (really desired output, in our case PAR) then you have?
<a href=showthread.php?s=&postid=11946700#post11946700 target=_blank>Originally posted</a> by BeanAnimal
Both will HEAT a closed bucket of water to the same temperature at the same rate. [/B]
Well I take issue with that over simplification :lol: "rate", same amount yes.....but rate? A heater is optimized for transfer, a pump not so much.....might take a tad longer but we'll get to the same point...........just say'n
BeanAnimal
02/26/2008, 11:30 AM
And this where overall efficiency DOES come into the game. That has been the joke with LEDs all along. Very few LEDs come anywhere close to being as efficient as MH or T5 bulbs. That is of course starting to change with each new generation of LED devices.
JMaxwell
02/26/2008, 11:59 AM
<a href=showthread.php?s=&postid=11946700#post11946700 target=_blank>Originally posted</a> by BeanAnimal
Take two devices that draw exactly 50 Watts, say a heater and a pump. Both will HEAT a closed bucket of water to the same temperature at the same rate.
The pump is efficient at moving water but not efficient at making light. The light is not efficient at moving water but in compression is efficient at making light.
I'd say it was more accurate to say that the heater and the pump will put the same amount of energy per unit time into a bucket of water. Some (hopefully a lot of) of the pump energy will go toward moving the water around. This energy will dissipate through the bucket walls and will not result in as much an increase in water temperature as the bucket with the heater ever. There is really no such thing in the real world where the energy can not escape, so I don't think its useful to say that the heater and the pump are the same in a closed bucket.
Energy, work, heat are the same units (joules, calories or Kwh) and can be converted mechanically, electrically, chemically, etc, but there are always efficiency losses and entropy to deal with. In theory, losses don't exist, in the real world, they most certainly do. When electrical energy is supplied to a light, some (hopefully most) of the energy is converted to light, some is converted directly to heat, some is lost to heat in the wiring, some of the heat is dissipated (sp?) through ambient air convection, etc.
I don't know squat about T5 vs. MH, but my own education in physics and thermodynamics leads me to think that it is possible that one type of light source can be more efficient than another at converting electrical energy into useful light with less heat imparted into the water. This is the practical problem. How do you get the most useful light without excess heat into the water. The answer is different for everyone because sometimes heating the water is good.
And that's all I have to say about that.
BeanAnimal
02/26/2008, 12:21 PM
I'd say it was more accurate to say that the heater and the pump will put the same amount of energy per unit time into a bucket of water. Some (hopefully a lot of) of the pump energy will go toward moving the water around. This energy will dissipate through the bucket walls and will not result in as much an increase in water temperature as the bucket with the heater ever. There is really no such thing in the real world where the energy can not escape, so I don't think its useful to say that the heater and the pump are the same in a closed bucket.
Yes, of course the movement of the water will heat the walls of the bucket, which will in turn allow some of the "energy" to escape without directly heating the water. The same goes for the sound of the moving water :)
However, it is an experiment that the "avarage joe" can perform to get an understanding of energy. The loses will be minimal to the heat that IS retained. Insulate the bucket and the lid and the losses become almost insignifcant.
Energy, work, heat are the same units (joules, calories or Kwh) and can be converted mechanically, electrically, chemically, etc, but there are always efficiency losses and entropy to deal with. In theory, losses don't exist, in the real world, they most certainly do. When electrical energy is supplied to a light, some (hopefully most) of the energy is converted to light, some is converted directly to heat, some is lost to heat in the wiring, some of the heat is dissipated (sp?) through ambient air convection, etc. Yes, you have no arguement here. We can get down to the nitty gritty and figure out where each bit of it went. On the same token, that is why we can't say that two 250W lights heat the tank exactly the same, even if both systems use the same amount of energy.
I don't know squat about T5 vs. MH, but my own education in physics and thermodynamics leads me to think that it is possible that one type of light source can be more efficient than another at converting electrical energy into useful light with less heat imparted into the water. This is the practical problem. How do you get the most useful light without excess heat into the water. The answer is different for everyone because sometimes heating the water is good. Yes, each technology has a different efficiency and heating characteristic to the items around it.
I am late for a meeting, but will post a graphic when I get back.
Enjoy the afternoon folks...
SimilanRocks
02/26/2008, 01:06 PM
I don't think MH will put less heat radiation to the tank than T5. You would need to proof with some numbers of total radiation out of the same watt from both. For me on similar set up they heat up the tank about the same.
I bought T5 a year ago because people on RC were saying T5 is more efficient and less heat, latest and greatest, simply not true based on my experience so far. I believe they are about the same efficience and heat. T5 is a lot more complex to set up because it needs more bulbs, more ballasts, more individual reflectors. People need to stop giving advise that T5 is latest and greatest. It's not!
kzooreefer
02/26/2008, 02:02 PM
A watt is not a watt when it comes to lights. Take for instance compact fluorescent and incandescent light bulbs. A 23 watt compact fluorescent will put out the same amount of light in lumens as a 100 watt incandescent bulb.
http://www.energystar.gov/index.cfm?c=cfls.pr_cfls
The incandesent bulb is very inefficient and converts a lot of those watts into heat and not light. Now as compared to PC's, T5's are supposed to be even more efficient at producing light with less heat generated.
My own experience is only with T5's and PC and I've seen a 5 degree drop in tank temp since I switched over to T5's. Same wattage of lights and pretty much same design of the fixture and number of fans.
JMaxwell
02/26/2008, 02:06 PM
<a href=showthread.php?s=&postid=11947229#post11947229 target=_blank>Originally posted</a> by BeanAnimal
[b]
Yes, of course the movement of the water will heat the walls of the bucket, which will in turn allow some of the "energy" to escape without directly heating the water. The same goes for the sound of the moving water :)
However, it is an experiment that the "avarage joe" can perform to get an understanding of energy. The loses will be minimal to the heat that IS retained. Insulate the bucket and the lid and the losses become almost insignifcant.
[b] Yes, you have no arguement here. We can get down to the nitty gritty and figure out where each bit of it went. On the same token, that is why we can't say that two 250W lights heat the tank exactly the same, even if both systems use the same amount of energy.
[b] Yes, each technology has a different efficiency and heating characteristic to the items around it.
I am late for a meeting, but will post a graphic when I get back.
Enjoy the afternoon folks...
Work? I thought you just posted on RC. Are you also going to try to get us to believe that you actually have a fish tank?:D
I would dispute the contention that the temperature of the water in an insulated bucket with a pump would ever reach the level of the same bucket with a heater in it, but that's really just dependent on the efficiency of the insulation, so we have no disagreement and I am blathering. Again, as a practical matter, under any real world scenarios, heaters heat the water, pumps move the water around, and some lights might put a better mix of light and heat into the water than others. For example, the Solaris LED...just kidding.
Here is a graphic for you:
:-)>
Its quite simple, but so am I.
PS: You, BA, are a wealth of information and a big contributor to this site, so please take the above in good humor.
kzooreefer
02/26/2008, 02:38 PM
While a 100 watt heater, pump and light bulb all consume the same amount of power, 100 watts, they all produce different kinds of energy from that power supply. Heat energy, mechanical energy and light energy. The heater would be the most efficient at producing heat as that is all it is designed to do.
ErikS
02/26/2008, 03:24 PM
<a href=showthread.php?s=&postid=11948069#post11948069 target=_blank>Originally posted</a> by kzooreefer
The incandesent bulb is very inefficient and converts a lot of those watts into heat and not light. Now as compared to PC's, T5's are supposed to be even more efficient at producing light with less heat generated. [/B]
Energy is energy is energy..................light is?
Open your blinds on a window that faces south on a sunny day......the temp of the room will?
kzooreefer
02/26/2008, 03:24 PM
I found this article dealing with lighting
http://www.aboutlightingcontrols.org/education/papers/high-low-bay.shtml
Towards the end of the article they compare T5HO to Metal halide with this conclusion:
Fluorescent vs. metal halide (324 watt T5HO vs. 400 Watt MH)
"At first glance, it may be difficult to understand how a 400W metal halide lamp, which is rated to produce 36,000 initial lumens, can be replaced one for one by four T5HO lamps. The answer is in lamp lumen depreciation—the rate at which light output declines over time. Standard metal halide lamps experience a higher level of lamp lumen depreciation than T5HO and T8 lamps. A 400W metal halide lamp can lose 35% of its light output at 40% of life, while a T5HO fluorescent will lose only 5-6% of its light output."
"Looking at mean lumens, a 6-lamp T5HO system produces about 20% more light output while consuming about 20% less energy than a 400W metal halide."
wharfrat48
02/26/2008, 03:26 PM
So on a watt vs watt basis, when comparing MH to T5, both will produce a similar amount of heat although heating the tank may be different between the 2 types of light. But isn't the real benefit of T5's is that you need alot less "wattage" to light the same size tank as you would if you were using MH's?
black9ice
02/26/2008, 03:51 PM
WOW, now I know why the internet is so bad for wrong information!
kzooreefer, is on the right track.
Since we have one point of energy (electric), this topic ends pretty fast. If you were using different types of energy and 1 source type to compare consumption or used energy (conversion), that would be a better argument.
But you are comparing 2 completely different consumers, if I must call it that for the simpletons. Therefore your thoughts are not valid.
Light energy does not equal heat!
The conversion process from electrical energy to light energy "can" produce heat energy. Based on different methods (MH, Florescent, etc.) you cannot compare the two in terms of heat energy. There are too many factors that would play a role on both sides, MH vs. Florescent.
BeanAnimal
02/26/2008, 03:54 PM
http://www.reeflogix.com/images/rc/ledheat.jpg
BeanAnimal
02/26/2008, 03:58 PM
The led column has changed a bit over the last year, but you get the idea.
The metal halide produces slightly more visible light than the fluorescent. Notice that the MH also produces more radiant energy and therefore will direclty heat the water more than the fluorescent lamp of the same wattage.
JMaxwell, thank you for the compliment. I certainly enjoy a good converstation and your input is helping contribute to just that.
kzooreefer
02/26/2008, 03:58 PM
Metal Halides, from what I've been able to research, initially produce a higher amount of light than T5's, 42,000 lumens compared to 36,000. I think you may also derive from that as more light per watt equals less heat given off.
BeanAnimal
02/26/2008, 04:05 PM
<a href=showthread.php?s=&postid=11948376#post11948376 target=_blank>Originally posted</a> by kzooreefer
While a 100 watt heater, pump and light bulb all consume the same amount of power, 100 watts, they all produce different kinds of energy from that power supply. Heat energy, mechanical energy and light energy. The heater would be the most efficient at producing heat as that is all it is designed to do.
In a narrow sense yes. But a 100 watt lightbult, a 100 Watt pump and a 100 watt heater are no different at all! Each is just as efficient as producing heat. None of the devices store energy and therefore produce heat at the rate they consume the energy (when looked at in an insulated box).
We use insulated boxes to determine how much energy an object consumes or contains. It is called a calorimeter :)
Is 1000W infrared ceramic heater more efficient than a 1000W hotplate? One heats the room by convection and one by radiation, they both have the same efficiency. Take it a step further. Putting a 200W fan on an 800W heater results in the same efficiency because 1000W is being pumped into the room.
BeanAnimal
02/26/2008, 04:07 PM
<a href=showthread.php?s=&postid=11949004#post11949004 target=_blank>Originally posted</a> by kzooreefer
Metal Halides, from what I've been able to research, initially produce a higher amount of light than T5's, 42,000 lumens compared to 36,000. I think you may also derive from that as more light per watt equals less heat given off.
Not really. Study the table above. They ALL give off the same heat. The only difference is HOW that heat is given off.
black9ice
02/26/2008, 05:30 PM
Gawd, I know you are trying to sound edumacated and all but please please stop and retake pyshics 101!
Here is an article that explains what a watt is, and even a joule:
Link explaining (http://www.greentechmedia.com/articles/energy-and-power-units-page3.html)
Tang Salad
02/26/2008, 05:35 PM
<a href=showthread.php?s=&postid=11949807#post11949807 target=_blank>Originally posted</a> by black9ice
Gawd, I know you are trying to sound edumacated and all but please please stop and retake pyshics 101!
Here is an article that explains what a watt is, and even a joule:
Link explaining (http://www.greentechmedia.com/articles/energy-and-power-units-page3.html)
Perhaps you should explainidicate to whom this is directed. ;)
Tang Salad
02/26/2008, 05:44 PM
Thanks for the chart Bean; it's worth at least a thousand words.
<a href=showthread.php?s=&postid=11948994#post11948994 target=_blank>Originally posted</a> by BeanAnimal
The metal halide produces slightly more visible light than the fluorescent. Notice that the MH also produces more radiant energy
The difference in radiant energy is only 5%. Very small, almost insignificant, in my book.
<a href=showthread.php?s=&postid=11948994#post11948994 target=_blank>Originally posted</a> by BeanAnimal
and the MH therefore will direclty heat the water more than the fluorescent lamp of the same wattage.
Again, only by a tiny fraction.
New Question for this thread: Is this 5% difference in radiant energy the only factor that backs up the claim that T5s heat the tank less than MHs?
If so, I'm ready to call this Myth Busted! :lol:
(Please assume all other variables are equal, i.e. equally well-designed and well-ventilated canopy/pendant etc.)
BeanAnimal
02/26/2008, 06:04 PM
You pretty much got it Tang :)
Tang Salad
02/26/2008, 06:14 PM
Thanks a lot Bean, I really appreciate your input. :)
BeanAnimal
02/26/2008, 06:24 PM
Don't trust me, trust the physics! I just slept at a Holiday Inn Express last night.
Off to the WABAC machine, Mr Peabody is waiting.
SeanySean
02/26/2008, 06:28 PM
Would the MH not heat the aquarium more due to it being a directed source kinda like a magnifying glass?
Sean
BeanAnimal
02/26/2008, 06:32 PM
Sean,
That is certainly a possible factor (there are many) to consider. You may want to note that T5 SLR reflectors are also very efficient and put a very large portion of the reflected light into the water.
Each setup is different, but all in all the MH and T5 lamps are very similar in their overall radiation. With quality reflectors, most of that radiation will end up in the tank
USC-fan
02/26/2008, 06:34 PM
MH are easier to cool than a t5 set up!!
SeanySean
02/26/2008, 06:38 PM
Thanx Bean, I have both setups combined and all I know for sure is my room heats up like crazy in the summer :)
wet reefer
02/26/2008, 06:51 PM
Interesting and usefull topic. Not bad for a bunch of unedumicated simpletons.
:beer:
BeanAnimal
02/26/2008, 06:51 PM
Yes it is much easier to remove heat from a confined area like a MH pendant. The higher Delta T helps the heat to flow faster into the surrounding environment. The T5 fixtures also trap a lot of heat and prevent air movement.
Either type of setup can be properly cooled if a little bit of thought is used!
mhurley
02/26/2008, 07:18 PM
black9ice,
That's 1.
Please, we're doing our best to keep a friendly dialog here. Please keep your comments to being civil and not insulting.
SimilanRocks
02/26/2008, 07:41 PM
Wow this thread grew to 3 pages in a day. Great info!
BeanAnimal, I was looking for the numbers for a long time. Thanks for sharing. I have some more thoughts based on those numbers.
The visible light also be the light that plant/coral can use (in very wide range). That means MH output more usable light 25% than T5.
MH bulbs will have UV shield that means most of 19% UV radiation is blocked before reaching the tank (or your coral won't survive). Meaning MH with UV shield will give LESS radiation to the tank than T5.
I'm not sure about IR. T5 does have a lot but what is the effect to the tank and corals?
BeanAnimal
02/26/2008, 07:49 PM
Those numbers came from a Department Of Energy white paper. I will try to find the link for it. Sanjay used parts of it in his MACNA talk.
I would guess (could be wrong) but the IR does little but add heat. I don't think the corals have IR receptors and I think the wavelength is too long to be harmful in any way. IR is just above the visible spectrum. UV, just below it. Usually it takes highly concentrated long wavelengths to be damaging. I.E microwaves are safe until you concentrate them.
Sanjay or somebody with a biology background would be better suited to answer that question. The same goes for the useable light spectrum. I can make educated comments about the subject, but nowhere near what some of the other guys can. So instead of putting my foot in my mouth, I will let one of them answer.
SimilanRocks
02/26/2008, 07:51 PM
<a href=showthread.php?s=&postid=11948709#post11948709 target=_blank>Originally posted</a> by kzooreefer
I found this article dealing with lighting
http://www.aboutlightingcontrols.org/education/papers/high-low-bay.shtml
Towards the end of the article they compare T5HO to Metal halide with this conclusion:
Fluorescent vs. metal halide (324 watt T5HO vs. 400 Watt MH)
"At first glance, it may be difficult to understand how a 400W metal halide lamp, which is rated to produce 36,000 initial lumens, can be replaced one for one by four T5HO lamps. The answer is in lamp lumen depreciation—the rate at which light output declines over time. Standard metal halide lamps experience a higher level of lamp lumen depreciation than T5HO and T8 lamps. A 400W metal halide lamp can lose 35% of its light output at 40% of life, while a T5HO fluorescent will lose only 5-6% of its light output."
"Looking at mean lumens, a 6-lamp T5HO system produces about 20% more light output while consuming about 20% less energy than a 400W metal halide."
I don't know if I can believe these companies. Changing light system is their business. The bulb life they are talking about is like 5 years. Most people will not keep more than a year. Many people trend to keep T5 longer than MH.
I don't believe those pictures too. Of course if you change from 4 years old MH to brand new T5 it's going to put out more light.
Here is another source I found comparing lm/W http://www.plantedtank.net/articles/Light-Bulb-Comparison/29/
hahnmeister
02/26/2008, 08:29 PM
Also keep in mind that the bulbs in most of these tests being compared are daylight spectrum. As you move to 10,000K even, the advantage halide has goes away fast because halides suck at making blue light (both efficiency as well as longevity) compared to say, T5s.
The implimentation of T5s over the tank often results in more light going into the tank as well. Look inside a canopy that uses T5s vs. one with halides... the halide lit one often is rather bright inside, meaning less light is going into the water. The T5 ones are rather dark... because, well, more of the tank is covered with reflector.
A more linear light source will also carry further than one that is more of a point source (halide). So comparing PAR really depends on where exactly.
Altpers0na
02/26/2008, 08:32 PM
so you think your MH are the same temp as your T5's?
take 2 fixtures.
400w's each
grab a T5 bulb with your left hand..
grab a MH bulb with your right hand..
use your left hand to call 911.
---------------------------------
they should both put 'about' the same amount of energy in the tank.
but, the MH source point should put hot spots in the water, the T5 should heat the tank more evenly.
compare this to standing in a house with a fireplace vs one with central air.
both heat sources will heat the whole house, but no one ever got burned from standing on a central air vent.. (if they did, something was very wrong)
hahnmeister
02/26/2008, 08:44 PM
Thats true. For many the difference observed between halide and T5s is simply the fact that the T5s tend to have built in fans, and halides not usually. Adding a fan system to a halide unit though (like lumenarcs with the duct mod) can really take a bite out of the heat. But if both systems were left with no active cooling, I would bet any money on the T5 lit system heating up a tank quicker (as I have actually 'been there, done that' with 277 watts of T5 vs. 275 watts of halide over two 40B's). The pocket of warm air between the t5s and water leaves little area for cooling, and with halides being mounted up higher, as well as taking up less space usually, there is more of a chance for passive cooling. Still, add some fans to either system and the convected/conducted heat is taken away.
BeanAnimal
02/26/2008, 08:45 PM
so you think your MH are the same temp as your T5's? I don't think anybody said or infered that. There is no doubt that the arc in a MH lamp is MUCH hotter than the glowing gas in a T5 lamp.
They give off the same amount of heat (calories) but over a different surface area via a different reaction.
PrangeWay
02/26/2008, 08:47 PM
I switched from a single 250W DE HQI light to 6-39W (234W) Tek Fixture (which aren't known for their cooling). Instead of the tank kickin up to 81 in the day when I was at work (this was in Texas) it'd only hit 79 or so...
So why was it cooler?
Well to start we're not in a closed system. The "watts" are turned into light and heat based on the efficency of the bulb (I believe there are previous posts on this). For now we'll address the heat...
My MH was a pendant fixture it was 16 x 10 hung 7 inches above the tank. Now see their is air between our lights and our water so there is going to be heat dissipation in this area. It's not all magically being transferred into the water. This fixture would than total 1120 cu in of air, hence there will be more Joules at the fixture than at the water. The Tek fixture I replaced it with is 36 x 15 hung 3 inches above the tank for 1620 cu in of air for heat transfer.
Both these where passively cooled fixtures, but there was a fan providing airflow between the fixture and water surface. If the MH was in an actively cooled fixture like the Aquctnics and still a Tek might the results have been different? And I'm sure there are other factors to play, but I keep my Thermodynamics book at work and don't like to think at home to come up with other temp + and -'s that the one change of light made :)
Now of course someone that is looking at this as a closed system again will say, "but that air will warm the tank!". Well no, cause the air is in my house, which was in Texas, which is in the US, which is on Earth. No closed system, tons of effects going on (like my ac).
On another note that was an odd occurance is with the t5 my corals on all levels had minor bleaching (not white, just paler). This was more from parts of the corals recieving direct light and uv that they didn't get under a point source. Unexpected but nifty.
So on that note try not to fall into rote declarations of "MH's are to hot, use T5's" or of course the equally as lame "T5's aren't cooler!" Cause depending on your UNIQUE setup and operating parameters either could be case, and in both declarations just make you look like a fanboi!
PW
BeanAnimal
02/26/2008, 08:55 PM
Yes every setup differs and thus will dictate what type of fixture will impart more (or less) heat into the water.
tonyf
02/26/2008, 10:17 PM
Bean, nice to see you back, mate!
BeanAnimal
02/26/2008, 10:24 PM
:)
hahnmeister
02/27/2008, 02:01 AM
PrangeWay, I noticed you noted UV as a possible cause of the lightening of your corals when switching from the halide to T5s. If anything, it would be the other way around though. Halides, even DE with the sheild, are known to put out much more UV than tubes any day (unless its a special made UV tube). Just wanted to let you know. I wouldnt doubt that going from an old bulb to a new set of T5s might have shocked some though.
PrangeWay
02/27/2008, 07:17 AM
If anything, it would be the other way around though. Halides, even DE with the sheild, are known to put out much more UV than tubes any day (unless its a special made UV tube).
Ah but again MH are a point source, and with a single halide on a 3ft tank a coral is only taking direct UV from one angle/side. Otherside, front, back (unless it was centered than only front, back) are catching waves that have bounced around a bit. Once you throw some t5's in there a coral that's hasn't been hit by direct light (and as a byproduct uv) on that surface of the coral in like 2 or 3 years is suddenly hit by some you're going to get a reaction.
It'd be an intersting experiment to find a way to calculate the amount of light, par and spectrum hitting any given surface of a coral in each setup. Also I'm guessing incredibly hard and complicated to do.
Though I doubt any of that is going to effect heat :)
PW
wharfrat48
02/27/2008, 08:01 AM
Not ever having MH's I'm not sure, but isn't the amount of wattage needed, being left out of this discussion? My 180 is lit by 456 watts of T5's, wouldn't a typical 180g SPS, clam tank, require more than 450 watts if halides were being used? Not to mention the need for some sort of actinic supplement? So even if the actual "heat per watt" is similar, you would need more watts on a MH system. Is this true? How many MH watts are needed for a 180g sps tank? and how many watts of actinic supplementation?
BeanAnimal
02/27/2008, 08:09 AM
<a href=showthread.php?s=&postid=11954338#post11954338 target=_blank>Originally posted</a> by hahnmeister
PrangeWay, I noticed you noted UV as a possible cause of the lightening of your corals when switching from the halide to T5s. If anything, it would be the other way around though. Halides, even DE with the sheild, are known to put out much more UV than tubes any day (unless its a special made UV tube). Just wanted to let you know. I wouldnt doubt that going from an old bulb to a new set of T5s might have shocked some though.
Yes... a standard fluorescent tube does not put out UV (tanning bed bulbs do however). It would follow that bulbs of different spectrums emit varying levels of UV radiation.
hahnmeister
02/27/2008, 02:26 PM
wharfrat48, that is somewhat true, but I think it varies from coral to coral more. I cant comment on overall wattage, but as far as the actual light field intensity I can. The linear/spread out field that a T5 array gives, from my experience, seems to be able to grow many SPS corals in lower intensities than the point source of a halide...
I have some of those prostrata SPS types that are usually thought of as 'halide only' because they need at least 400-500 micromol/m2/s of intensity to color in well. And for halides, this seems to be true. These corals need to be within the top 12" of the tank, right under a halide... the higher the better. The thing is, this close to the halide, their tips get alot of light, but this results in alot of shadows being cast onto the lower branches. Sure, I could lower the coral, but then it would just brown out. Otherwise, the coral tips color in well, but the undersides tend to fade a bit.
With the T5s, I can put these bright pink/blue millis in a 250-300 zone, and they color in very well all over. The light from the T5s doesnt cast as many shadows, and sure, the tips of the corals arent as intense exactly, but the entire coral as a whole has much better pigmentation. The same goes for blue tort in particular (a species that really seems to like T5s over halide).
So while the light from the T5s might have less intensity up top, its ability to illuminate more of the coral's surface area seems to be a huge advantage.
Im sure this is also a huge disadvantage, in the case of corals that dont want as much light because they cant adjust themselves as well towards or away from the light source.
aninjaatemyshoe
02/27/2008, 02:50 PM
Hahn, are you still using a MH on a light mover or are you now more into T5s?
reeformadness
02/27/2008, 03:52 PM
<a href=showthread.php?s=&postid=11945746#post11945746 target=_blank>Originally posted</a> by BeanAnimal
A 100 watt lighbult heats the room just as much as a 100 watt heater or a 100 watt speaker. Watts are watts :)
Its not quite that simple. You have to consider that with 100% efficient lighting then 100 W of electicity would be converted to 100 W of light. But we all know lighting is not 100% efficient. What really happens is that some of the electricity is converted to heat instead of light. The reason MH's heat a tank less than T5's is because MH's are more efficient (lumens/watt). It just doesn't seem they put off less heat because of surface area. That's one of the biggest reasons to put a fan on your lights. The cooler they are, the brighter they burn. So, a 100W incandescent (low-effieciency) is going to produce more watts of heat than 100W of fluorescents (high-efficiency.)
BeanAnimal
02/27/2008, 04:32 PM
<a href=showthread.php?s=&postid=11958811#post11958811 target=_blank>Originally posted</a> by reeformadness
Its not quite that simple. Actually, yes it is :)
By definition, if two or more items each consume 100W of power, they each produce 100W of heat. Energy can not be created or destroyed, it can only be converted to work, transferred as heat or stored. If it is "in the room" then it is heating the room or being stored. Remember WORK is also heat because no motion is perpetual.
If you wish to make the argument that some of the light energy is chemically converted and stored in the animals and plant life, then you would be correct. You would also be correct if you said that any of the light that escapes the room through the window would be lost with reference to the room. The buzzing of the ballast heard outside of the room would also be a loss. Nobody has said any differently :)
These loses are rather insignificant when looking at the big picture and can be accounted for. 100W being consumed in your living room is going to put ~100W of heat into your room, no matter what is consuming that power, be it a fan or a heater. The fan may cause the curtains to blow around, but this energy causes friction and heat, the curtains do not store the energy.
Build 2 insulated wooden boxes that are 1 foot cubed. Place a 100W bulb into 1 box and a 100W fan on the other. Both boxes will gain temperature at the same rate and reach the same final (stable) temperature. Why? Because both boxes are being pumped with 100W of power. That is WHAT a Watt is, a unit of measure for energy (power).
You have to consider that with 100% efficient lighting then 100 W of electricity would be converted to 100 W of light. But we all know lighting is not 100% efficient. Even if it was 100% efficient, it would still be in the room and end up as heat. I think that is what many of you are missing. Efficiency has nothing to do with it from this frame of reference.
The reason MH's heat a tank less than T5's is because MH's are more efficient (lumens/watt). It just doesn't seem they put off less heat because of surface area. If you look at the table, you will find that to be untrue.
http://www.reeflogix.com/images/rc/ledheat.jpg
Notice the the MH has slight more radiant energy. Be careful with the word efficiency. Without units or a frame of reference it is meaningless.
That's one of the biggest reasons to put a fan on your lights. The cooler they are, the brighter they burn. Actually, no. Each type of bulb has a target envelope temperature for its rated spectrum and optimum efficiency.
So, a 100W incandescent (low-effieciency) is going to produce more watts of heat than 100W of fluorescents (high-efficiency.) No, the more efficient lamp will produce more light, but both will produce the same amount of heat. Efficiency is not relevant to heat, it applies to the frame of reference for which a piece of equipment is being examined. Efficiency has to have units with it to be meaningful. Is the light more efficient at making UV or Visible light? A pump is not efficient at making light and a light is not efficient at moving water, but either could do, well, either. Notice that the MH is much more efficient at producing UV and that the T5 is much more efficient at producing infrared? Notice that the the LED is MUCH MUCH MUCH more efficient at producing convected and conducted heat, NOT radiant energy (light)?
reeformadness
02/27/2008, 05:23 PM
The chart above actually explains my point. I was wrong about about the effiency of incandescent light bulbs though. I guess when you factor in infrared light, they are pretty efficient. But notice that the sum always comes to 100%. The sum of heat plus radiant energy equals 100%. So therefore, a bulb that produces more radiant energy per watt will produce less heat per watt. That's why a 100 watt bulb will not heat a room more than a 100 watt heater. I'm not sure about metal halides and fluorescents, but it is quite true that LED's burn brighter at cooler temperatures. But please look at your chart and realize what my point is. Its that some of those watts coming in go out as watts of radiation (such as light), and some of those watts coming in go out as watts of heat (wasted energy as far as I'm concerned). But a watt is a watt. The total watts in equals the total watts out. So a 100W fan and 100W lightbulb in insulated boxes with everything else equal will not end up at the same temperature.
hahnmeister
02/27/2008, 05:54 PM
reeformadness, Bean is correct and here is why:
Light is a form of heat. Energy can neither be created nor destroyed. A 100 watt fan and a 100watt bulb in a calorimeter will result in the same temperature increase. If you impliment some system of removing the conducted/convective heat (fans), then all you have is radiant heat... which is visible light, UV, IR, etc. From this standpoint, a light source like say, an LED, will heat the tank less because its also producing less light... they are directly proportional. All you can do is try to limit the spectrums you dont need, like UV and IR, to minimize radiant heating.
BTW, LED's do not burn brighter at cooler temps. They are simply better at migrating that heat from the diode to the heatsink and wicking away the heat than a halide or T5 which cant have a heatsink planted right on the bulb. LED's tend to have an advantage in that they can limit the amount of UV and IR (non-visible radiation) so besides visible light, very little heat is transferred. Comparing a LED to say, a T5 would depend on which two in particular though, since there are LED's which CAN put out a good amount of IR/UV, and there are T5s which put out little to none as well as the other way around.
BeanAnimal
02/27/2008, 06:01 PM
So therefore, a bulb that produces more radiant energy per watt will produce less heat per watt. Radiant energy IS heat :)
That's why a 100 watt bulb will not heat a room more than a 100 watt heater They will both impart the same amount of heat into the room. They are both 100 Watts.
I'm not sure about metal halides and fluorescents, but it is quite true that LED's burn brighter at cooler temperatures LEDs are pure current devices. Heat = Resistance and Resistance = a drop in current. So heating an LED die causes resistance that causes a reduction in current and therefore a reduction in output. LEDs are VERY different from other lighting technologies.
But please look at your chart and realize what my point is. Its that some of those watts coming in go out as watts of radiation (such as light), and some of those watts coming in go out as watts of heat (wasted energy as far as I'm concerned). Nobody has said anything any different :) The bigger picture is that it ALL becomes heat. Radiation, Convection, Conduction. Light, Sound, Motion... it is all ENERGY. :)
The total watts in equals the total watts out. So a 100W fan and 100W lightbulb in insulated boxes with everything else equal will not end up at the same temperature. They most certainly will. The temperatures will rise at equal rates and reach the same stable temperature at the same time. That is WHY we can label both devices as consuming 100W.
We can do the same in reverse. Take two insulated boxes. Place 100W heater in one box and an unknown device in the other. The POWER usage of the unknown device can be measured with a thermometer! The ratio of the temperature to the known box and the power ratio will be the same. We call it a calorimeter!
BeanAnimal
02/27/2008, 06:06 PM
Doh, hahn posted while I was composing!
Pork chop time folks... I am using my Watts to feed my belly.
reeformadness
02/27/2008, 06:07 PM
If you read the literature for different LED's at lumileds website there you will find charts of "luminous efficiency" for each model of LED they make. They put out more lumens at lower temps than they do at higher temps. Light is not a form of heat. It is a form of energy. Just like heat is a form of energy. Just as mechanical energy (like a fan) is a form of energy. The problem is that these machines don't convert 100% of the electical energy into the energy we want. Some of it is always wasted as heat energy. But a fan will not necessarily waste as much energy as a light bulb.
hahnmeister
02/27/2008, 06:07 PM
Using a 100 watt light source that can convert 25% (an efficient halide) of its wattage into light vs. one that can only convert say, 15% (PC) just means that you would be able to get away with less watts of halide (60 watts) to get the same light as 100 watts of the PC. THEN you have a tangible reduction in heat, however, only in the form of cunducted/convected heat, since the radiant output per watt for the halide is higher than the PC. So if you are able to remove all conductive/convective sources, then really, the heat that 60 watts of halide and 100 watts of PC transfer to the tank is the same.
This is another potential advantage of LED's down the road. Due to their almost fibre optic like ability to focus their output of light, you can mount them high above the water of the system you intend to illuminate with little to no loss. Even with the best of halide reflectors that can keep most of the light that bounces off a reflector facet in a beam, the entire front surface of the bulb emits light that never hits a reflector, and so it radiates outward in all directions. Simply put, you could place a LED 10' above your reef tank and see very little loss of light due to light 'bleeding' out to the sides. You would have to have a very complex and rather inefficient halide reflector to do the same... perhaps something with an optical lens like an LED, or a compound/reflex reflector (like a photographer's studio) on the bulb so that none of the light leaving the unit is 'uncontrolled'. Still, at best the results would suck. Anyways, this ability to mount an LED so high yet yet maintain a tight focus means convected and conducted heat can be kept very far away from the water... a huge bonus. But it still means your A/C will have to deal with the heat produced by the fixture unless you duct it out of the house.
reeformadness
02/27/2008, 06:10 PM
Calorimeters measure heat energy. I'm not trying to be difficult it is just that radiation (radiant energy) is not heat energy.
reeformadness
02/27/2008, 06:12 PM
I have no disagreements about LED's. They are the future of aquarium lighting for the reasons you mentioned.
hahnmeister
02/27/2008, 06:14 PM
<a href=showthread.php?s=&postid=11959903#post11959903 target=_blank>Originally posted</a> by reeformadness
If you read the literature for different LED's at lumileds website there you will find charts of "luminous efficiency" for each model of LED they make. They put out more lumens at lower temps than they do at higher temps. Light is not a form of heat. It is a form of energy. Just like heat is a form of energy. Just as mechanical energy (like a fan) is a form of energy. The problem is that these machines don't convert 100% of the electical energy into the energy we want. Some of it is always wasted as heat energy. But a fan will not necessarily waste as much energy as a light bulb.
You are a Marine Biologist... you should know better, or take a thermodynamics course to correct your understanding. Light is most certainly a form of heat... radiant heat. Energy and heat, or 'thermal energy' are one and the same after all. 'Heat' is just a 'non-technical' term for the same thing, but heat IS energy.
3 types of heat: convective, conductive, and radiant. Energy can not be created or destroyed. When you look at the actual breakdown of what the units stand for, you will see that they are one and the same.
BeanAnimal
02/27/2008, 06:16 PM
<a href=showthread.php?s=&postid=11959903#post11959903 target=_blank>Originally posted</a> by reeformadness
If you read the literature for different LED's at lumileds website there you will find charts of "luminous efficiency" for each model of LED they make. They put out more lumens at lower temps than they do at higher temps. Nobody has said anything to the contrary.
Light is not a form of heat. It is a form of energy. And when the light strikes something it either does work or becomes heat. If it does work, the work becomes heat. LIGHT=HEAT. Energy can not be created or destroyed.
The problem is that these machines don't convert 100% of the electical energy into the energy we want. Some of it is always wasted as heat energy[b][quote] What we want and wasted are frames of reference but have nothing to do with the physics :)
[b][quote]But a fan will not necessarily waste as much energy as a light bulb. Waste in what frame of reference? Moving air or creating light? If the both use the same amount of energy, they both impart the same amount of heat into the box because they both consume the same amount of energy.
hahnmeister
02/27/2008, 06:20 PM
<a href=showthread.php?s=&postid=11959936#post11959936 target=_blank>Originally posted</a> by reeformadness
Calorimeters measure heat energy. I'm not trying to be difficult it is just that radiation (radiant energy) is not heat energy.
So what is a radiant heater then? Think about it.
Im not trying to 'prove you wrong' here, but rather 'bridge the gap' you have in your understanding. You are SOOO close to getting it, and then this whole argument is null and void.
If you pump the equal of 100 watts of pure light energy (not a 100 watt bulb, but 100 watts of pure light energy, as in if you use a 25% efficient 400 watt bulb and remove all the non radiant heat from the situation) into a calorimeter, you will get the same rise in temperature as if you just put a 100 watt heater inside of it.
There are other forms of Energy other than just heat (Kinetic/Momentum, Stored/Potential, Chemical, none of which are in play here), but all heat is a form of energy, and all light is a form of heat which is a form of energy. Light is just a form of radiation, so we normally dont equate it with the forms we usually see, like conduction (cooking in a fry pan), or convection (central duct heating). But radiation, AKA the EM spectrum, is a form of heat. It may be able to travel across great voids in a vacuum, but it is still a form of heat. The Microwave region, the X-ray, Gamma-Ray, etc... all forms of heat (microwave should be dead obvious). We may not be able to see them, but still the same none the less. Stand under a skylight and feel the heat.
rishma
02/27/2008, 06:20 PM
do you mean a watt of light or a watt of heat???
hahaha....just kidding.
reeformadness
02/27/2008, 06:25 PM
Man, you scarfed that down! :) I agree heat is energy, but energy is not necessarily heat. Yes, when the light strikes something it becomes heat. But the light itself is not heat. Just because I am a marine biologist doesn't make me an expert on thermodynamics, but I have had college physics. When I say waste I mean convert to convective/conductive heat instead of its prefered energy.
BeanAnimal
02/27/2008, 06:25 PM
<a href=showthread.php?s=&postid=11959936#post11959936 target=_blank>Originally posted</a> by reeformadness
Calorimeters measure heat energy. I'm not trying to be difficult it is just that radiation (radiant energy) is not heat energy.
And HEAT = ENERGY so a calorimeter measure ENERGY. See how neat and tidy (and simple) it all really is.
hahnmeister
02/27/2008, 06:25 PM
<a href=showthread.php?s=&postid=11960049#post11960049 target=_blank>Originally posted</a> by rishma
do you mean a watt of light or a watt of heat???
hahaha....just kidding.
:p
A watt of magnetic field perhaps...lol.
BeanAnimal
02/27/2008, 06:29 PM
<a href=showthread.php?s=&postid=11960093#post11960093 target=_blank>Originally posted</a> by reeformadness
Yes, when the light strikes something it becomes heat. But the light itself is not heat No it is not heat, it is energy and energy = heat.
Just because I am a marine biologist doesn't make me an expert on thermodynamics, but I have had college physics. When I say waste I mean convert to convective/conductive heat instead of its prefered energy. You have your head 99% wrapped around this! Not bad for a marine biologist. If I likely could not easily get my head wraped around many of the concepts you deal with daily... at least without a lot of brow beating and frustration.
Have fun!
reeformadness
02/27/2008, 06:29 PM
My point is that some electrical energy coming into your lights, for example, is converted to conductive/convective heat and some is converted to useful radiation. MH's are better than T-5's by a little bit in terms of light delivered vs. heat delivered.
hahnmeister
02/27/2008, 06:37 PM
<a href=showthread.php?s=&postid=11960093#post11960093 target=_blank>Originally posted</a> by reeformadness
Man, you scarfed that down! :) I agree heat is energy, but energy is not necessarily heat. Yes, when the light strikes something it becomes heat. But the light itself is not heat. Just because I am a marine biologist doesn't make me an expert on thermodynamics, but I have had college physics. When I say waste I mean convert to convective/conductive heat instead of its prefered energy.
I think I covered what is important, and I think you were going to arrive at the same conclusion if you didnt get sidetracked by some incorrect assumptions:
100 watts is 100 watts, and the irony is that the more efficient light of the two will not only light up the tank more, but also transfer more heat to it in the form of radiation.
The advantage of a ligh technology, or its goal, is to convert more of its watts/energy into radiant heat rather than conductive/convective. This way, you can use less wattage to get the same amount of light.
For Example, lets say you use some really bad light source... something that only converts 5% of its output to light, and is say, 1000 watts. So 50 watts is all that gets converted to light, and the rest becomes conducted/convective heat. Then, we have another source that is from the future, and it can convert 50% of its wattage into light and is 100 watts. Now, if both light sources can have all their conducted/convected heat removed (a duct on the reflector to vent the air outside), and both have similar reflectors/methods or transfer to the target, which will heat the target more?
Neither, they are the same.
If the conducted/convected heat ISNT removed, then it is a matter of 100 watts vs. 1000 watts though, and although it may not heat up the target (unless in an enclosed hood w/o venting), it will heat up the room/house that the source is in.
BeanAnimal
02/27/2008, 06:50 PM
Yes, I scarf meat quickly :) Actually the warden is at the gym and I am eating with the laptop at the table. The pork is gone and I am on the 5th or 6th Reeses egg. I keep them in the fridge where radiant, convective and conductive heat can't make them warm.
Good thread guys... thanks for the fun conversation.
reeformadness
02/27/2008, 06:53 PM
OK. I can agree with that. You are assuming 100% of the conductive/convective heat is removed of course. In that case, you are correct. I know part of my problem was symantics (my fault),but I still don't think you will ever remove 100% of the conductive/convective heat, and therefore, light that produces more radiation (radiant heat it turns out) vs. conductive/convective heat, will keep a tank cooler at the same lumens (but not watts). So you are right, but you have to admit it was somewhat of a loaded question (even though it wasn't intentionally.)
hahnmeister
02/27/2008, 06:54 PM
<a href=showthread.php?s=&postid=11960131#post11960131 target=_blank>Originally posted</a> by reeformadness
My point is that some electrical energy coming into your lights, for example, is converted to conductive/convective heat and some is converted to useful radiation. MH's are better than T-5's by a little bit in terms of light delivered vs. heat delivered.
I know what you are getting at here, on an unrelated note. But most of the 'facts' that you might get from lighting mfg's and other sources in the lighting field are dealing with 3000-6500K bulbs for the most part. In the 10,000K-20,000K and beyond realm, Halides lose their advantage quickly because Halides suck, I repeat SUCK, at making blue light compared to T5 phosphors.
If you look at the actual PAR of the most efficient halides... pulse start/DE 3000K-4000Ks, they peak at about 105 lumens per watt. Now, I know its a flawed scale to use since the lumen scale doesnt favor blue very well, but just in going from 3000K to 6500K, there is a huge drop (depends on whos bulb, but sometimes 50% right there), and for sure a 50% drop in output between 3000K and 10,000K. Even if you measure this in the radiometric scale (PAR), you will still see a significant drop despite the greater amount of blue produced. And then its no secret that in going from a 10,000K to a 20,000K, the PAR of most bulbs drop again about 50%. The figures I have seen from PFO, Icecap, etc are pretty pathetic looking... I think thats why they dont publish them. In the end, you are lucky if your 20,000K is making more than 20 lumens per watt... and we know that even in the PAR scale, thats a huge drop in output as you go bluer. The only reason some bluer halides have a good PAR at all compared to others (or why 400 watt 20,000Ks actually have pretty decent outputs in proportion to the 10,000Ks when compared to lower wattages) is because they try to keep a good amount of their daylight spectrums. If there was a halide with just a monochromatic blue peak to it (like a blue+ T5), its output would be pathetic. By comparison, you can look up the efficiency of a GE 3000K or 6500K T5, and measure that with a PAR meter... its pretty good. 85 lumens/watt I seem to remember. And as you go to a 11,000K (aquablue), or even a blue+ bulb... they retain most of this output... more than half actually. I dont have numbers off the top of my head, but if a 6500K/3000K (pretty similar) has a PAR at some point of 430, the blue bulb is going to be over 300. So watt for watt, T5s end up being very competitive when it comes to the spectrums we want for our reef tanks usually. Unless you are someone like Sanjay who likes to run 10,000K/14,000K daylight halides w/o suppliments, T5s are most likely your most efficient option.
Also, there is the output over time which has been brought up before. Halides see a huge decrease in output over time, where T5s tend to suffer a small initial drop in the first few months, then very little for months and months after. This has been brought up before, but the mean output of a T5 is often alot higher than a halide. Of other consideration then is the shock that happens when you change a bulb that degrades this much over its lifespan to the coral. If a halide is only running at 50% after a year (not uncommon for those with probe start/SE bulbs), when you replace them you have just doubled your lighting over the tank... ouch!
reeformadness
02/27/2008, 06:55 PM
Well maybe nobody asked! :)
hahnmeister
02/27/2008, 07:02 PM
<a href=showthread.php?s=&postid=11960347#post11960347 target=_blank>Originally posted</a> by reeformadness
OK. I can agree with that. You are assuming 100% of the conductive/convective heat is removed of course. In that case, you are correct. I know part of my problem was symantics (my fault),but I still don't think you will ever remove 100% of the conductive/convective heat, and therefore, light that produces more radiation (radiant heat it turns out) vs. conductive/convective heat, will keep a tank cooler at the same lumens (but not watts). So you are right, but you have to admit it was somewhat of a loaded question (even though it wasn't intentionally.)
I remove all my conducted/convective heat...lol. I use fans in the canopy which force the hot/humid air out of the house all together through a 4" duct. If anything, my tank lowers in temp when the fans/lights come on because the evaporative cooling which is increased due to the fans and lights (the fans move the air, but light energy/heat has been shown to be a very effective means of evaporative cooling on its own even).
As far as many people are concerned, they ARE in fact removing most of the heat their lights conduct/convect. The only exception would be an enclosed canopy or room perhaps, but even an open-top reef with only passive cooling allows very little convective heat into the water (if you have a bulb that is actually conducting heat into the water, you have problems...lol), since heat rises on its own. So a canopy or fixture, while it may heat the room, is moving most of the convective heat away from the water in most cases. I suppose if you have a hot ballast under the tank in a stand, or a light on the refugium under the tank, then you are convecting heat to the tank possibly, but otherwise, it shouldnt be a major concern.
The moral of the story: keep that air moving, or even better yet, remove it all together!
reeformadness
02/27/2008, 07:03 PM
That is good stuff to know. I knew I had T-5's for a reason! I really do like them. How about VHO's? I have heard they are best for actinics, and I did notice a decrease in flourescence when I changed to 3 T-5/1 T-12 (but to be fair its a completely different selection of bulbs). I want to get some par readings on my bulbs. I bought a lux meter but I'm not sure if I'll get PAR from it or not. I was thinking about using filters to break the light into components but I'm not sure if it will work.
hahnmeister
02/27/2008, 07:30 PM
Converting the Lux to PAR will be near impossible even with the filters. The % errror will no doubt be higher than the figure you are trying to arrive at (source A has an output of 100 microMol/m2/s +/- 100! Lol.).
Luckily, there are plenty of others with PAR meters, and some with spectralradiometers who can simply take the readings once, and then just publish that result.
VHO's have an advantage with actinic because they are larger diameter. Actinic phosphors are the most sensitive to heat/energy, and so a narrow diameter bulb in theory keeps them closer to the current in the center of the bulb. However, one of the major components of T5s is their superior/newly developed phosphors which are able to withstand higher temps. Even though actinics may not be the longest lasting T5s, they are still T5s. In the end, I bet their longevity/output per watt is about the same as VHO's, maybe a little better depending on the brand. It seems to me that ones with a 'cold spot', as in the Giesemann's, Aquascience, and other NARVA made bulbs are able to hold up longer than ones w/o because the heat in a 'cold spot' T5 is more concentrated at the end, sparing the phosphors along the tube from any more heat than needed. T5s w/o cold spots (ATI/ Sylvania makes) have their heat removed along the entire length of the bulb, which makes me wonder as to their longevity. My ATI blue+ bulbs really dove in output after 9 months, even with active cooling, but my Giesemann actinic + bulbs (same spectrum) are killing it still. Heck, the PAR from my G-man actinic+ bulbs is higher than the Giesemann aquablues now! Go figure. Then again, every UVL Super Actinic I have ever seen/had has had a very short life (some bad out of the box of course, most last no more than 6 months), but Im sure thats a mfg problem. Still, if the 4' SA's I have for my T5 bulb comparison test are dull out of the box like some of the ones before, Im just going to publish it. With such poor QC, the fact that their may be some 'defects' that I could use to RTV the bulb means little to me when this rate is so high (every single Super Actinic I have ever had) has done this.
But back to what you said about actinics in T5 vs VHO...
Well, most of the time when I see people complain about T5 actinics, its because they had for example dual 110 watt bulbs over their tank, and they swapped it out for dual 54 watt bulbs. Well, gee... thats 108 watts of T5 vs. 220 watts of VHO. Even though T5s have the reflector advantage, I dont know how much that can make up for, esp with VHO's that have internal bulb reflectors. And I dont think T5s maintain their output advantage in the actinic range as well due to their narrower diameter as some of the other spectrum phosphors which arent as sensitive to heat.
Luckily, the real bulb to look at with T5s isnt the actinic, but the blue+ style/22,000K bulb. This 450-460nm peak just kills, and it a very long lived phosphor as well. FWIW, if you are supplimenting a halide with it, chances are it is a 10,000K or 14,000K with a very healthy actinic peak in the first place. What these spectrum bulbs lack is a blue spike actually, 450-460nm, not actinic or 420nm. The only bulbs I would suppliment with an actinic would actually be the bluer 14,000Ks like the pheonix, and some 20,000Ks which have a huge blue spike, but usually lack actinic all together (monochromatic blue/ 'neutered' bulbs). The Saki 6500K has more actinic than any 20,000K, and the ushio 10,000Ks and 14,000Ks have more than any other halide pretty much around... you just dont see it with all the other daylight spectrums. What they need is blue, not actinic. The only reason for actinics with these bulbs is really just for looks/after hours viewing.
reeformadness
02/27/2008, 07:51 PM
You are right about blue light being better than actinics, but the actinic light just looks so much better in my opinion. I know its silly. I actually had 3 superactinics and one aquasun VHO's. Talk about fluorescence. The whole room looked like it was lit with a blacklight! If you are into "green" lighting and PAR and such as you seem to be then you should read this:
http://www.biolbull.org/cgi/reprint/134/3/411.pdf
It has great info on light requirements of zooxanthellae (granted its only one species). It really helps put spectrum into perspective. 440 nm seemed to be the best peak. But believe it or not there is a substantial peak in the IR at 720 nm. Maybe those incandescents aren't useless!
rishma
02/27/2008, 07:54 PM
A watt of magnetic field perhaps...lol
no, we really should be discussing quanta:watt ratio.....:rolleyes:
it is amazing to me that this thread has gone on 4 pages. the horse has started to decompose.
I am not being critical, I am just surprised.
In my mind, the real value in this type discussion is focused on methods to mitigate heat transfer to our tanks, including different approaches to lighting. I struggled for years with tank temperature and the assoicated issues with high evaporation rates, energy costs, etc. My current tank is totally free of heat concerns, which allows me to focus on other aspects like better husbandry practices. I am even thinking of adding some more light, without any real concern for temperature impact.
My sucess managing temperature issues is based on significantly improved efficiency in water movement, filtration choices, an lighting. Basically, I have a lot less watts for the same size tank. Electricity bills are very low and the tank is a stable 78 and a heater is required to keep it there. I may have gone a little overboard. The biggest improvement was in water movement with fewer watts, but lighting changes also played a role.
With reflector selelction, I was able to lift my hallides well above the water, limiting radiant transfer, and improving natural convective heat transfer to the room (not the water). This is a major advantage with hallides. I have been wanting to add T5 for actinic supplimentation, but the will need to be much closer to the water and I am unsure how to incorporate them with the current set-up......off topic.
when comparing watt per watt for different systems, I think it is helpful to focus on limiting heat transfer to water (yes, every watt goes somewhere....into the room as we say) and par/watt ratios.
just my 0.01333 Euros....
reeformadness
02/27/2008, 08:05 PM
I can't believe how fast I helped fill that last page up! But in defense of the thread, I certainly learned alot in the last couple of hours. Which is kind of the point isn't it? I used to have major problems with heat. Believe it or not, the biggest thing I ever did to lower tank temp was move my tank 6" further from the wall (to fit a new sump underneath.) The best discoveries happen by accident.
JMaxwell
02/29/2008, 12:54 AM
<a href=showthread.php?s=&postid=11960704#post11960704 target=_blank>Originally posted</a> by hahnmeister
Converting the Lux to PAR will be near impossible even with the filters. The % errror will no doubt be higher than the figure you are trying to arrive at (source A has an output of 100 microMol/m2/s +/- 100! Lol.).
Luckily, there are plenty of others with PAR meters, and some with spectralradiometers who can simply take the readings once, and then just publish that result.
VHO's have an advantage with actinic because they are larger diameter. Actinic phosphors are the most sensitive to heat/energy, and so a narrow diameter bulb in theory keeps them closer to the current in the center of the bulb. However, one of the major components of T5s is their superior/newly developed phosphors which are able to withstand higher temps. Even though actinics may not be the longest lasting T5s, they are still T5s. In the end, I bet their longevity/output per watt is about the same as VHO's, maybe a little better depending on the brand. It seems to me that ones with a 'cold spot', as in the Giesemann's, Aquascience, and other NARVA made bulbs are able to hold up longer than ones w/o because the heat in a 'cold spot' T5 is more concentrated at the end, sparing the phosphors along the tube from any more heat than needed. T5s w/o cold spots (ATI/ Sylvania makes) have their heat removed along the entire length of the bulb, which makes me wonder as to their longevity. My ATI blue+ bulbs really dove in output after 9 months, even with active cooling, but my Giesemann actinic + bulbs (same spectrum) are killing it still. Heck, the PAR from my G-man actinic+ bulbs is higher than the Giesemann aquablues now! Go figure. Then again, every UVL Super Actinic I have ever seen/had has had a very short life (some bad out of the box of course, most last no more than 6 months), but Im sure thats a mfg problem. Still, if the 4' SA's I have for my T5 bulb comparison test are dull out of the box like some of the ones before, Im just going to publish it. With such poor QC, the fact that their may be some 'defects' that I could use to RTV the bulb means little to me when this rate is so high (every single Super Actinic I have ever had) has done this.
But back to what you said about actinics in T5 vs VHO...
Well, most of the time when I see people complain about T5 actinics, its because they had for example dual 110 watt bulbs over their tank, and they swapped it out for dual 54 watt bulbs. Well, gee... thats 108 watts of T5 vs. 220 watts of VHO. Even though T5s have the reflector advantage, I dont know how much that can make up for, esp with VHO's that have internal bulb reflectors. And I dont think T5s maintain their output advantage in the actinic range as well due to their narrower diameter as some of the other spectrum phosphors which arent as sensitive to heat.
Luckily, the real bulb to look at with T5s isnt the actinic, but the blue+ style/22,000K bulb. This 450-460nm peak just kills, and it a very long lived phosphor as well. FWIW, if you are supplimenting a halide with it, chances are it is a 10,000K or 14,000K with a very healthy actinic peak in the first place. What these spectrum bulbs lack is a blue spike actually, 450-460nm, not actinic or 420nm. The only bulbs I would suppliment with an actinic would actually be the bluer 14,000Ks like the pheonix, and some 20,000Ks which have a huge blue spike, but usually lack actinic all together (monochromatic blue/ 'neutered' bulbs). The Saki 6500K has more actinic than any 20,000K, and the ushio 10,000Ks and 14,000Ks have more than any other halide pretty much around... you just dont see it with all the other daylight spectrums. What they need is blue, not actinic. The only reason for actinics with these bulbs is really just for looks/after hours viewing.
so...after all that, what is the blue+ 450-460 T5 to get for supplementing a daylight looking halide that already has actinic?
hahnmeister
02/29/2008, 01:57 AM
Aquascience, ATI, Giesemann... the usual suspects. I cant say what caused my ATI's to dip honestly. It could be the ballasts even, so I cant say anything for sure. All I know is that even when new, varying the fan speed didnt change the wattage or output compared to when I do the same with the Giesemann. The more air I passed over the Giesemann, the higher its output/wattage went up... but with the ATI, not so... it was rather weird.
Konadog
03/23/2008, 02:57 PM
This thread has been nominated for April's Thread of The Month (http://www.reefcentral.com/forums/showthread.php?s=&threadid=1352831).
BeanAnimal
03/23/2008, 03:30 PM
kinda funny... I think most peoples eyes glaze over when the physics books come out.
This really isn't a difficult problem to solve. I'm not afraid of the physics books. ;) All you need to do is measure the current draw of each ballast before the ballast and after the ballast, to determine ballast efficiency.
Taking a known or estimated efficiency of the bulb in lumens/watt will tell you how much energy goes into waste heat.
The combination of the ballast efficiency and the bulb efficiency will yield the total efficiency.
BeanAnimal
03/27/2008, 03:46 PM
<a href=showthread.php?s=&postid=12189952#post12189952 target=_blank>Originally posted</a> by Kep
This really isn't a difficult problem to solve. I'm not afraid of the physics books. ;) All you need to do is measure the current draw of each ballast before the ballast and after the ballast, to determine ballast efficiency.
Taking a known or estimated efficiency of the bulb in lumens/watt will tell you how much energy goes into waste heat.
The combination of the ballast efficiency and the bulb efficiency will yield the total efficiency.
That is not what is at issue here really. The efficiency will tell us how much of the used energy MAY find its way into the tank. However, that is only part of the equation. The spectrum of the emitted light also determines how much of that energy is going to be absorbed by the tank.
When we are talking about the "room" than watts are watts and we don't need to be concerned with efficiency, we can simply loolk at the actual watt usage of each device and determine the heat load on the room. A 100W fan and a 100W ballast both put the same amount of heat into the room.
pjr300
03/30/2008, 09:58 PM
Good thread. I thought I was insane a few years ago when my 2 x250w halide system ran cooler than the TEK light that I tried for 60 days. A feel better about my sanity now... well, at least a little. :-)
hahnmeister
03/30/2008, 10:15 PM
<a href=showthread.php?s=&postid=12215359#post12215359 target=_blank>Originally posted</a> by pjr300
Good thread. I thought I was insane a few years ago when my 2 x250w halide system ran cooler than the TEK light that I tried for 60 days. A feel better about my sanity now... well, at least a little. :-)
I had the same experience when I first tried a tek as well... it shot the tank right up to 84 degrees while in the same room, on another identical size tank, the 250wattDE (both systems were 275-277 actual watts) tank was holding at 80 w/o fans on either system. In the end, what I needed was a cross-flow fan on the tek light to keep it cool... then it was smooth sailing. In the end, I think its more of an issue of how you impliment your cooling solution (I think I have said that before in this thread even). If you hook up halides and get those reflectors with the ducting right on the bulb (lumenarc3's for instance), you would be amazed how cool halide can be. As it is, most halide systems lack cooling since the bulbs themselves dont need it, but with T5s, the bulbs need it, so it just so happens that they tend to come with fans, which in turn keeps the tanks cooler as well usually.
OTOH, there is the issue of efficiency. If you can produce more light with the T5s per watt than halide, well... then its a no-brainer since you are able to use less watts of T5s than the halide. IME, this depends mostly on spectrum since phosphor based bulb are great at making blue light, but suck at making daylight (ok, not suck, but they arent as good at it as halides). But usually, for those who prefer the 20,000K look, yes, you can get away with less T5 wattage than you would have with halide and get the same intensity... in which case then yes, the T5s are cooler.
pjr300
04/01/2008, 05:46 PM
The lumenarc 3 reflectors look great, but I don't thinl I can fit them under my canopy (btw, I've taken off the cover, so it's more of a frame than a real canopy these days).
So, given that I'm using a pair of 14K halides with a pair of actinincs, then maybe I should consider a T5 setup. It sounds like I could get equal power and similar color temps. I just need to use fans (like I learned the hard way with the fan-less TEK setup).
pjr300
04/01/2008, 06:11 PM
Of course, thinking about this a little more: couldn't any halide system run cool like the luumenarc if there were some 4" vent holes stategically placed in the top, and maybe a fan or 2 drawing the hot air up and out?
Tang Salad
04/01/2008, 06:17 PM
<a href=showthread.php?s=&postid=12215484#post12215484 target=_blank>Originally posted</a> by hahnmeister
As it is, most halide systems lack cooling since the bulbs themselves dont need it, but with T5s, the bulbs need it, so it just so happens that they tend to come with fans, which in turn keeps the tanks cooler as well usually.
Very good point.
astowers1
04/01/2008, 07:04 PM
I am taking off my nova extreme with 2-150k and 4 vho for 2-250's in a canopy. Think it will raise my tempereature?
Tang Salad
05/01/2008, 08:28 AM
Bump...more people need to read this thread! :D
sirreal63
05/01/2008, 09:35 AM
Agreed 100%
styndall
05/08/2008, 09:11 AM
<a href=showthread.php?s=&postid=12191921#post12191921 target=_blank>Originally posted</a> by BeanAnimal
When we are talking about the "room" than watts are watts and we don't need to be concerned with efficiency, we can simply loolk at the actual watt usage of each device and determine the heat load on the room. A 100W fan and a 100W ballast both put the same amount of heat into the room.
This is true so long as you define "room" properly. Can you see the tank lights from your windows when you drive up to the house? Then the street is part of your "room." Do some of those photons exit the atmosphere and hit the asteroid belt? Then your "room" just got a whole lot bigger.
The total amount of energy in the universe (the only closed system we know about) is conserved, but to suggest that because of that, all bulbs are the same at heat production is being quite pedantic and more than a little silly. Lots of kinds of lamps will be more or less efficient at producing visible light and photosynthetically-available radiation, while the rest of the energy is wasted on non-visible and non-PAR heat.
BeanAnimal
05/08/2008, 09:44 AM
<a href=showthread.php?s=&postid=12496926#post12496926 target=_blank>Originally posted</a> by styndall
This is true so long as you define "room" properly. Can you see the tank lights from your windows when you drive up to the house? Then the street is part of your "room."
[Sigh].... Of course it is. However, the amount of energy that escapes via light-through-the-window is negligible with regard to the wavelengths we are talking about. If you read the entire thread, I clearly indicated that there were losses but the "room" model/analogy was valid even when considering those loses.
Do some of those photons exit the atmosphere and hit the asteroid belt? Then your "room" just got a whole lot bigger. Again, there are losses in the system. The losses are not relevant to the overall discussion. The hum of the ballast that is heard OUTSIDE the room is energy escaping, but that too is not relevant.
The total amount of energy in the universe (the only closed system we know about) is conserved, but to suggest that because of that, all bulbs are the same at heat production is being quite pedantic and more than a little silly. Pedantic and silly? I suppose I should take that as an insult, but instead I will chuckle. Your nit-picking of the photons escaping to the depths of space and the wavelengths of light that pass through the window are rather silly.
The "room" as it relates to the topic at hand is a valid and useful model to demonstrate the basic physics at hand. What about the energy stored by the corals, shall we count that also? No, it has no bearing on the basic concept at hand because that quantity is so small it does not matter.
By this point in your education, you should understand the concept of a model as it is used to describe a basic set of assumptions that we know to be true. The quantities of energy that escape our "model" are very low and well outside the significance of the topic at hand. We can replace many "complex" systems with "black box" models that have a fairly predictable input and output. I (we) have done so here.
Going through thousand of complex computations for a given "room" and "light" will not provide an answer that deviates significantly from the predictable results.
Furthermore, the "losses" in the comparable systems will be very similar with regard to what "escapes" and therefore mostly cancel each other with regard to the "room" as a model.
Lots of kinds of lamps will be more or less efficient at producing visible light and photosynthetically-available radiation, while the rest of the energy is wasted on non-visible and non-PAR heat. yup, but most of it ends up as heat in the room one way or the other and thus we are back to the basic point at hand. Watts are Watts. You can get your quantum calculator our and tell us how many photons escaped if you like, but from a pragmatic and reasonable standpoint, Watts are Watts when comparing equipment attached to our aquariums.
styndall
05/08/2008, 10:18 AM
The important point isn't the "light-through-the-window" bit of my post, but rather that the idea that every part of every watt of energy used by a light eventually ends up as heat is a very poor way to understand lighting and efficiency in our tanks. Some lights produce more photo-synthetically available radiation per watt, and these lights are more efficient, and, since more of this radiation goes toward chemical reactions and growth instead of hitting something and heating it a bit, these lights will cause less heat in the tank generally. Put a 100 watt space heater in one canopy and a 100 watt halide or t5 set in another and measure the difference and your comparative coral growth, and you'll see that your model is basically worthless for discuss light effectiveness in aquaria.
fivesmallworlds
05/08/2008, 11:31 AM
<a href=showthread.php?s=&postid=12497393#post12497393 target=_blank>Originally posted</a> by styndall
Put a 100 watt space heater in one canopy and a 100 watt halide or t5 set in another and measure the difference and your comparative coral growth, and you'll see that your model is basically worthless for discuss light effectiveness in aquaria.
Very funny mental picture right now...
BeanAnimal
05/08/2008, 01:23 PM
<a href=showthread.php?s=&postid=12497393#post12497393 target=_blank>Originally posted</a> by styndall
The important point isn't the "light-through-the-window" bit of my post... You have only illustrated that you have missed the entire point of the conversation. It is that simple.
Lets state this in very basic terms. No matter what type of electronic device we put in our "room", for our purposes a Watt of energy consumed is a Watt of heat imparted to the room. The sound, light, etc that "escapes" the "room" is insignificant when comparing the devices. PERIOD.
You are trying to contort that simple fact with the complexities of the systems that underly the transfer of that energy.
Some lights produce more photo-synthetically available radiation per watt, and these lights are more efficient, Nobody has said anything any different. Please stop inferring that I do not understand this. If you go back and READ the posts in this thread, you will see that this topic has been fully covered.
Also, be careful how you use the word efficienct. It has to be in CONTEXT. Efficient at producing what? PAR?, PUR?, UV-A?, UV-B?, IR?, Etc.
The more you say the more you make my point and obfuscate your own.
and, since more of this radiation goes toward chemical reactions and growth instead of hitting something and heating it a bit, these lights will cause less heat in the tank generally. Not within the significance of the conversation. That is the POINT you are missing.
Put a 100 watt space heater in one canopy and a 100 watt halide or t5 set in another and measure the difference and your comparative coral growth, and you'll see that your model is basically worthless for discuss light effectiveness in aquaria. That has to be the most intellectually dishonest statement I have read so far. Of course a heater will not grow coral, nobody said it would. Of course the LIGHT will directly heat the water more due to radiation. Both will impart the same amount of heat into the room with the exception that a very small amount of the "light" will be lost if the room has a window. That lost light equates to a very small portion of energy that is not converted to heat IN the room. Again, not enough to worry about for the argument at hand.
I am going to kindly ask that if you wish to continue this conversation, that you keep your comments in line with the context that the original comments were made.
Your taking the salient points of this thread out of CONTEXT and trying to use them to discredit me in the process. The "model" proposed works just fine if it is used as proposed. We have a ROOM and a TANK that are, for the most part, isolated environments. We have talked about both and how they interact with our devices and the energy that they transfer.
Nobody said that a heater suspended above the tank would heat the water at the same rate as a light suspended above the tank. The CONTEXT for the energy comparison of the devices was within the confines of the ROOM, not the TANK.
It has CLEARLY been stated that each type of device has losses to the outside environment but those losses are insignificant with regard to the overall HEAT imparted to the ROOM.
It has CLEARLY been stated that different types of light sources impart HEAT/ENERGY to the TANK in different ratios of CONVECTION and RADIATION depending on the wavelength of the emitted light. That my friend is the crux of this discussion, not the missing photons or how many make a Watt.
The discussion of PUMPS, HEATERS, FANS and other energy conversion devices was merely to illustrate the use of power and the conversion of energy to add CONTEXT to the physics that govern this discussion. To take those remarks OUT of CONTEXT and make the argument you have is, well silly.
styndall
05/08/2008, 02:44 PM
EDIT: This post was snarkier than I intended. Honestly, though, your ad hominem remarks in the post above are uncalled for.
BeanAnimal
05/08/2008, 04:12 PM
Uncalled for? Give me a break. You started off with snarky remarks that were fully out of context with regard to the main points in this thread. When that was pointed out, you defended yourself with remarks that were even snarkier and yet more out of context.
You started out by trying to say that the "room" model I proposed was faulty because energy escaped. I stated that we had covered that many times and the "missing energy" was trivial with regard to the overall heat/energy left in the room.
You abandoned the first remarks and twisted the "room" model into the "tank" model and tried to portray me as too stupid to understand the difference. You are accusing me of ad-hominem remarks and attacks? Hrmm.
You proposed an absolutely silly scenario between a heater and a lamp that makes utterly no sense in the context of anything that has been said. You did so in a manner that attempts to portray my understanding as lacking. Your scenario was an attempt to put words in my mouth that are 100% contrary to everything I have said in this thread. I called your attempt to discredit me intellectually dishonest, because it is.
If you were here to kindly discuss this topic, then you would not have posted in the manner that you did. It is that simple.
Have a nice evening.
2farNorth
05/08/2008, 04:18 PM
<a href=showthread.php?s=&postid=12499367#post12499367 target=_blank>Originally posted</a> by styndall
your ad hominem remarks :rolleyes:
Interesting thread... I'm with Bean... A watt is a watt is a watt..... No matter how you look at it.... MH, T12, T8, T5, T2..... :D
I'll stick with my MH's and a fan...
styndall
05/08/2008, 04:57 PM
<a href=showthread.php?s=&postid=12500017#post12500017 target=_blank>Originally posted</a> by BeanAnimal
Uncalled for? Give me a break. You started off with snarky remarks that were fully out of context with regard to the main points in this thread. When that was pointed out, you defended yourself with remarks that were even snarkier and yet more out of context.
You started out by trying to say that the "room" model I proposed was faulty because energy escaped. I stated that we had covered that many times and the "missing energy" was trivial with regard to the overall heat/energy left in the room.
You abandoned the first remarks and twisted the "room" model into the "tank" model and tried to portray me as too stupid to understand the difference. You are accusing me of ad-hominem remarks and attacks? Hrmm.
You proposed an absolutely silly scenario between a heater and a lamp that makes utterly no sense in the context of anything that has been said. You did so in a manner that attempts to portray my understanding as lacking. Your scenario was an attempt to put words in my mouth that are 100% contrary to everything I have said in this thread. I called your attempt to discredit me intellectually dishonest, because it is.
If you were here to kindly discuss this topic, then you would not have posted in the manner that you did. It is that simple.
Have a nice evening.
The basis is this: in a simplified model, discounting the escape of light from your "room" and the absorption of light by photosynthetic life, then all lights powered by n watts produce the same amount of heat. These conditions don't exist. While the lights might produce similar amounts of total heat, variations in the spectrum produced (i.e. in the amount of light used by photosynthesis) and the conditions in which the tank sits will create variations in the actual amount of heat produced.
That's simple and direct, and is the whole of my argument. Your attacks are unjustified, and pretending that conditions are as simple as you have creates a model that, while it might be a reasonable approximation of reality, makes a fundamentally inaccurate claim. You should acknowledge this.
Also, you're being rude. Have a nice evening, indeed.
sabbath
05/08/2008, 06:00 PM
<a href=showthread.php?s=&postid=12500066#post12500066 target=_blank>Originally posted</a> by 2farNorth
:rolleyes:
Interesting thread... I'm with Bean... A watt is a watt is a watt..... No matter how you look at it.... MH, T12, T8, T5, T2..... :D
I'll stick with my MH's and a fan...
x2
ConcreteReefer
05/08/2008, 06:14 PM
I recently switched from MH's to T5's..
I was running around 500 watts with the MH's and got decent growth, color was ok, & heat was a problem- Turning my Chiller off my Temp would rise to 85-86 (maybe hotter, thats as high as it got before I turned the chiller back on)..
Now- I'm running 324 watts of T5's (6x54w)- I'm still getting decent growth, Awesome Color, better light penetration/spread, using less electricity, & my Chiller runs 1/2 the time it used too.
I would not use MH's again unless I had a tank that was 36"+ deep..
For med-small tanks- T5's are a better choice, period.
Take this from one of those "T5's will never be as good as MH guys"
btw- I'm using an ATI powermodule, This is one of the, if not *the best* T5 fixture on the market...
GSMguy
05/08/2008, 06:17 PM
Concrete what was your metal halide setup what reflectors fan setup??
your new fixture would not add heat because of its design, it is ventilated in a way that it doesn't add heat.
Pedro Borges
05/08/2008, 06:28 PM
What a bunch of non knowledge pseudo facts.
1. When you get 150W HQI you get a bulb that consumes 150W and turns >90% of those into light and the rest into heat.
2. When you get 150W T5 you get the same as in point 1, if it's a HE T5 light it will have slightly better ratio than most HQI and even HCI, if it's a HO T5 it will have little less.
3. Lights don't go on without ballasts, and ballasts HEAT up, and that heat comes from extra power consumption. a 150W HQI light with a ferromagnetic ballast will easily take over 180W from the plug, electronic ballasts on the other hand heat less, so take less extra power to operate, or the other way around if you prefer.
4. Spectrum of light or "radiation" as people like to fancy call it overrating their vocabulary over their knowledge differs from model to model, you can have and you do 2000ºK T5 and HQI as you can have 20000+ºK in both, so it's not that HQI "spectrum" penetrates the water or not, it's the color range that penetrates.
5. Tipically HQI's come with ferromagnetic ballasts and T5 only work with electronic ones and that also makes a difference.
6. its an obvious illusion that HQI are hotter because all the heat is concentrated in a small area as stated in the premier post.
Hope to help to get ideas clearer on this subject.
Cheers,
Pedro
BeanAnimal
05/08/2008, 06:44 PM
<a href=showthread.php?s=&postid=12500314#post12500314 target=_blank>Originally posted</a> by styndall
The basis is this: in a simplified model, discounting the escape of light from your "room" and the absorption of light by photosynthetic life, then all lights powered by n watts produce the same amount of heat. These conditions don't exist. They most certainly do. But, again you have not specified if we are talking about the TANK or the ROOM. This thread had related but very distinct topics in it. You have YET to be able to differentiate that fact.
Please carefully examine the following (as provided by the department of energy).
http://www.reeflogix.com/images/rc/ledheat.jpg
Notice the total radiant energy? What about the total HEAT? The ROOM model is very valid with regard to ANY of those light sources, or any electrical device for that matter, even a loudspeaker (most of the energy put into a speaker is converted directly to HEAT in the motor).
Better yet, notice that both the MH and T5 are around 25% visible light. How MUCH of that 25% do you think leaks out of the room before it contacts a surface and is converted to heat? Better yet, if both lights are compared in the SAME ROOM, then similar amounts of light would escape. Once again, the model is valid.
Also notice that the MH and T5 will directly impart similar amounts of heat (via radiation) direclty into the water. They only really differ in the amounts of IR and UV. Guess which one is more readily absorbed as HEAT when it strikes something with mass?
If you actually read the entire thread, you would have already seen all of this information discussed several times.
While the lights might produce similar amounts of total heat, variations in the spectrum produced Again, so what. Energy=Heat. Very little of that energy escapes the room and therefore it is converted to heat. This is not as hard as you are making it.
(i.e. in the amount of light used by photosynthesis) and the conditions in which the tank sits will create variations in the actual amount of heat produced. Are we talking about the heat in the water or the room. You keep flip flopping back and forth. They are two DIFFERENT systems. The ROOM however contains the tank and therefore all of the ENERGY in the tank is converted to HEAT in the ROOM.
You keep mentioning photosynthesis. The energy converted and stored is so small that ONCE AGAIN it is irrelevant in terms of our discussion of heat imparted to the TANK or ROOM.
That's simple and direct, and is the whole of my argument. You argument does not fit the context of this thread.
Lets put it this way. You are quibbling about the difference between Magnetic North and True North and Grid North when any of the three will get you in the right general direction if all you want to do is head "north".
Your attacks are unjustified, Again, give me a break. You jumped in here and attacked me. Your posts have all been snarky and condescending. You have done it in other threads when you feel you know more than a poster. This time you jumped in over your head and did so in an insulting manner. What do you expect in response?
and pretending that conditions are as simple as you have creates a model that, while it might be a reasonable approximation of reality, makes a fundamentally inaccurate claim. You should acknowledge this. Conditions are certainly that simple, as has been shown over and over in this thread. You have yet to show where I am inaccurate let alone focus on a topic. This thread is about the heat imparted to the tank by different lighting sources with a secondary topic touching on the heat imparted to the room by ANY device that uses (converts) energy. You have confused remarks from both topics. CONTEXT is the key to understanding any discussion. Your remarks clearly indicate that you are not responding to the remarks in context with the topics that they pertain to.
Also, you're being rude. May I remind you that your first post in this thread was riddled with condescension? Your second post did a bit of name calling? It amazes me how some people can launch an attack and then play the victim when they are unable to gain the upper hand with regard to the actual points of the argument.
Bottom line: (the same as it was 5 pages back)
With regard to the ROOM, a WATT is a WATT.
With regard to the TANK, there is LITTLE difference between the T5 and MH and in MANY cases the T5 imparts MORE heat into the tank than a MH of similar wattage.
styndall
05/08/2008, 06:57 PM
errr...
Your chart has different slots for radiant energy and heat for a reason. They're different. Failing to acknowledge that is failing to acknowledge that energy has different forms.
BeanAnimal
05/08/2008, 07:41 PM
<a href=showthread.php?s=&postid=12501169#post12501169 target=_blank>Originally posted</a> by styndall
errr...
Your chart has different slots for radiant energy and heat for a reason. They're different. Failing to acknowledge that is failing to acknowledge that energy has different forms.
I did not fail to acknowledge anything. This is getting silly. Please go back and READ the entire thread. This has ALL been covered. Of course the chart simply shows the differences in radiated, conducted and convected energy. I never said anything different and if you did in fact read what I posted (above and previously in the thread) that would be clear.
We can talk about the Radiant energy in context of the TANK and in context of the ROOM. Both topics have been covered fully in this thread.
As a simple recap:
Radiant energy is converted to heat with regard to the room. Both types of lamps output similar amounts of visible light, most of which is transferred to HEAT in the ROOM. If compared in the same MODEL then both will lose similar amounts to the outside environment (through a window for example).
Furthermore, because BOTH the MH and T5 have similar radiant energy emissions, then both impart similar heat directly into the TANK. The difference (as stated in the post above) is the amounts of UV and IR.
Where the light breaks down and PUR, PAR, LUMENS or whatever spectral scale you choose is not at all relevant because in ANY ratio, the amount stored or converted by the corals is insignificant with regard to the overall heat of the water AND/OR room. The thread IS NOT about how much growth per watt can be obtained.
The points that have been made by myself and others in this thread are fully supported by the facts and physics.
This exchange is getting rather silly. If and when you can show the points made in this thread to be invalid, then please do. Otherwise, this is pretty much a closed matter.
ConcreteReefer
05/08/2008, 08:25 PM
Dang, this thread is getting interesting
http://www.clipartof.com/images/emoticons/thumbnail2/1974_eating_popcorn.gif
just dave
05/08/2008, 09:05 PM
At least I now know what ad hominem and snarkier mean.
2farNorth
05/08/2008, 09:17 PM
Ya me too! Doesn't take a Grad Student to click 'search' on google!! :D
conjuay
05/08/2008, 09:33 PM
<a href=showthread.php?s=&postid=11943889#post11943889 target=_blank>Originally posted</a> by Tang Salad
It's another case of the laws of thermodynamics and conservation of energy at work. All light gets converted into heat; ergo equal light=equal heat. (Photosynthesis and other photo-chemical conversions aside...)
:)
No, sorry, wrong.
Light is a separate entity than heat. Heat is a byproduct of lighting.
Light is not heat, heat is not light.
This is what is called efficiency, the amount of light produced RELATIVE to the heat generated.
Black Mammoth
05/08/2008, 09:59 PM
WOW. There is A LOT of WRONG information in here. I'm not talking about the MH vs. T5 argument. For those that are reading this thread, please be careful. I'm going to stay out of this thread other than this warning. I know better :D
As Conjuay pointed out. Light != Heat and Heat != Light. That's just one of many items that isn't true. I'm only picking on this one since it was just brought up.
Also, keep in mind what is theoretical and what is real world application. Look at the empirical data as well. Bob had T5s and ran the tank without a chiller. Bob then switched MHs and needed a chiller. This is an example and not a claim.
GSMguy
05/08/2008, 10:18 PM
People always resort to name calling and silly, poorly supported, short sighted, "empirical" arguments when Beananimal has all the facts and knowledge on his side.
Bean is right here, and people need to stop posting "wow there is A Lot of WRONG in here" everybody does the same thing with him it gets old, using insults and poorly formed arguments to debunk him makes people look silly.
Black Mammoth
05/08/2008, 10:34 PM
<a href=showthread.php?s=&postid=12502880#post12502880 target=_blank>Originally posted</a> by GSMguy
People always resort to name calling and silly, poorly supported, short sighted, "empirical" arguments when Beananimal has all the facts and knowledge on his side.
Bean is right here, and people need to stop posting "wow there is A Lot of WRONG in here" everybody does the same thing with him it gets old, using insults and poorly formed arguments to debunk him makes people look silly.
OK. I decided to post again because obviously my post was mis-interpreted. I was not accusing Bean with wrong information. Actually, the example I used since it was brought up recently wasn't by him. FYI, there is nothing wrong with empirical data. My statement is true, there is a lot of wrong information people are posting, and I'm not saying Bean Animal. Someone with a PhD in EE would agree....as one is sitting next to me reading this :D
GSMguy
05/08/2008, 11:10 PM
if your EE has the time why not have him/her get in on the conversation.
hahnmeister
05/09/2008, 01:24 AM
Yeah, otherwise its the old "I know something you dont know that proves you are wrong but Im not gonna tell you" ploy. Not to mention, you dont need a PhD in EE to understand any of this, undergrad level thermodynamics explains it all.
BeanAnimal
05/09/2008, 05:29 AM
<a href=showthread.php?s=&postid=12502537#post12502537 target=_blank>Originally posted</a> by conjuay
No, sorry, wrong.
Light is a separate entity than heat. Heat is a byproduct of lighting.
Light is not heat, heat is not light.
This is what is called efficiency, the amount of light produced RELATIVE to the heat generated.
To use your words,
No, sorry, wrong :) Tang Salad has it right. This is thermodynamics 101 :)
Light is ENERGY and ENERGY = HEAT. If you go back and read this entire thread, this topic has been very thoroughly discussed. I will recap, but you should read from start to finish, as this has all been well covered.
The light emitted by the bulb (radiation) is energy. Energy can only be converted, used to do work or stored. It ALL becomes HEAT at some point. Please look up the definition of a "calorimeter". We describe electric devices in terms of the Watts that they "use". That means that if we know how many Watts a device uses, we know EXACTLY how much heat it produces.
Take 4 identical sealed (insulated) boxes. Place in the respective boxes:
100W heater
100W speaker
100W light
100W fan
All 4 devices use ENERGY differently. The heater directly produces HEAT and no light. The speaker creates SOUND (does work) and no light. The light emits light and no sound. The fan moves a mass (does work by moving the blades) and creates sound.
Each box will heat at the same rate and reach the same stable temperature. This is the most basic example of the Law of Conservation. It is they very reason that we can label devices with units like "Watts".
Now, which device is more efficient? You can't answer that question without putting a context to it. The fan is more efficient at moving air but less at making sound. The speaker is more efficient at making sound but not at light... etc. Notice that they all produce exactly the same amount of HEAT because HEAT = ENERGY.
liveforphysics
05/09/2008, 05:35 AM
Energy is energy.
Light is just a state of energy.
In our tanks, 0.001% (Likely less) of the light becomes converted in complex biochemical processes into chemical potential energy in photosynthetic organisms. Though it is the reason we create the light, it happens to be irrelevant to the thermal loading of a tank.
The energy added to a room is directly dependent on the energy entering the room. Your 400w of pumps (internal or external), 400w of any type of lighting, 400w of desktop computer you are reading this on all add exactly the same amount of energy into the room. It makes no different the brand, the theory of operation, the color, or if it's 400w of pure light energy sent straight from heaven into the room. If it's drawing 400w of electricity, and it's in the room, it's adding 400w of heat to the room. Even a refrigerator or chiller that pulls 400w adds 400w of energy to the room.
What matters to the tank is how well this energy is transfered into the tank.
Both T5HO and MH have good things and bad things going for them in regards to transferring energy into your tank.
In a perfect world, the small part (visible light) that everybody fusses over would be roughly a tie between MH and T5. This is because in a perfect world, you would have a perfect reflector for both your T5 and MH, so you wouldn't require any more wattage of one or the other to get the light levels you require.
In real life, we have to use garbage hobby quality reflectors (because the market won't support paying multi-thousand dollars for reflectors, and our canopies aren't big enough to hold them anyway).
Trying to reflect a point source requires a complex ($$$) shape to manufacture. We result to using bent aluminum sheet. Lumen-arcs (and clones) seem to be the only reflectors that makes an effort to get more than 60% of the light produced into the surface of the water.
The shape of a reflector for a linear source is much easier to make (bends are all in a common direction). It's so much easier to make that companies can produce T5HO reflectors that get 80-85% of the light the bulb produces to actually hit the water in the constraints of the critical angle of reflection window for water.
~60% vs ~85% usable lighting means you can get the same amount of light you require in your tank by using ~30% less watts of lamps over your tank when using T5HO.
This means less energy in the tank and in the room. This is a good thing for T5HO.
However, if you are running 400w of MH and 400w of T5, you don't have this advantage working for you.
Temperature difference is a key part of the rate in which energy is transfered. MH bulbs high a higher temperature difference between the surface of the bulb and the water (more prone to heat transfer). However, they also have a smaller surface area (less prone to heat transfer). T5 has more surface (more prone to heat transfer), and lower temps (less prone to heat transfer).
They both have good and bad points.
IMO- T5HO has a slight edge over MH because you can use less watts of light to get the same light into the tank, and because the bulbs can sit 2" off the surface of the water, which enables less light losses than MH.
In a closed system (aka, your tank room), light, sound, and all other types of energy added to the system ultimately become heat, and are modeled at heat loads.
If you wish to cool your tank, use fans to evaporate water.
1J = 1 watt-second
2,260J per 1 mL of water evaporated.
Therefore, if you have 400w of lighting for 8hrs a day (3.2kw-hrs), evaporate just 2,008ml (2 liters, about half a gallon) of water per day and you have absorbed the full amount of energy your lighting produces. You may say, "but I evaporate gallons of water each day, and my temperature is still high". This is very likely, and it means you have other heat contributers to your tank you likely never thought of which are contributing. In my tank, my sump return and closed loop being on 24-7 creates a similar amount of heat load to my entire lighting system because it only runs for 8hrs a day.
Evaporation is easy enough to do with a bit of airflow across the surface. The more water you evaporate, the more you cool your tank. If you live in an unfortunate place with consistent 100% relative humidity, you will need to find alternate methods of cooling. If you don't a little airflow over the surface of the tank will do wonders.
Best Wishes,
-Luke
BeanAnimal
05/09/2008, 05:46 AM
<a href=showthread.php?s=&postid=12502723#post12502723 target=_blank>Originally posted</a> by Black Mammoth
WOW. There is A LOT of WRONG information in here. Yes, there is. Most of it is from well meaning folks that do not have their head fully wrapped around basic thermodynamics and physics.
As Conjuay pointed out. Light != Heat and Heat != Light. You may want to rethink that part :)
Light IS ENERGY and ENERGY = HEAT therefore LIGHT = HEAT. Light is converted to HEAT when it comes in contact with matter. It may also be STORED or used to do WORK, both of which also turn into HEAT.
This is the Law of Conservation of Energy at work. It applies here and everywhere.
clevengergl
05/09/2008, 06:26 AM
<a href=showthread.php?s=&postid=12502723#post12502723 target=_blank>Originally posted</a> by Black Mammoth
As Conjuay pointed out. Light != Heat and Heat != Light. That's just one of many items that isn't true. I'm only picking on this one since it was just brought up.
I think that's what he meant too, Bean, so you guys are on the same page! :D I'm sticking around for this one! I love me a good, old-fashioned peeing contest!!!
Has there been any accepted conclusions on which style heats or doesn't heat the water any different than the others? I have read a lot here, but the bantering has overridden my 3rd grade attention span. LOL
BeanAnimal
05/09/2008, 08:09 AM
Laud, both the MH and T5 have very similar radiant outputs. The T5 has a higher IR outout, while the MH has a higher UV output. In the end, both types of lamps (if the same wattage) impart roughly the same amount of heat into the water.
The MH and its compact reflector may direct more heat downward into the tank via radiation and convection, while the T5 may have a better chance of radiating and convecting heat into directly into the room, due to the large surface area of the reflector. On the other hand, the T5 fixture will inhibit airflow to a greater extent, trapping more heat between the fixture and the water. This can create an environment where convective heat transfer is greatly increased.
In the end, it simply depends on the setup. If we take (2) 150W halide pendants and compare them to a 300W T5 fixture, the MH will likely heat the water less simply due to the fact that it allows a much greater air flow around the fixture and therefore reduces covective heat transfer to the water (in favor of the room).
If we stuff them (both types of fixtures) into closed hoods, then both setups will be about the same with regard to heat in the tank.
Hope that makes sense. :)
Paul_PSU
05/09/2008, 08:19 AM
I know that one of the main reasons that people use T5's is the different color combinations also, but comparing the same 300w setup Bean, which would cost less to to run?
Now we're getting somewhere....
RichConley
05/09/2008, 09:03 AM
<a href=showthread.php?s=&postid=12503635#post12503635 target=_blank>Originally posted</a> by hahnmeister
Yeah, otherwise its the old "I know something you dont know that proves you are wrong but Im not gonna tell you" ploy. Not to mention, you dont need a PhD in EE to understand any of this, undergrad level thermodynamics explains it all.
Exactly why I haven't posted on here in months.
Bean (and Hahn) are 100% correct here. If you took physics 1, you should understand this.
Black Mammoth
05/09/2008, 09:15 AM
LOL you guys are too much. I never disagreed with Bean and yet I'm referenced as saying he is wrong. At no point I made this claim. This is one of the reasons I chose to not discuss this in a technical matter.
Actually, Bean hit the nail on the head when started to talk about how the difference is in the setup of the lights. I never used any ploys except to be careful about some of the information being provided. Again, please show me where I said Bean was wrong. Stepping out again not unless someone can show where I said Bean was wrong on the information.
I know I asked this before, but how do you explain the brightness of normal florescent bulbs in, say a bathroom light fixture, that requires 39 watts but seems to put out more light than a 100 watt incandescent? ( I know I am being vaguely general, but..)
RobbyG
05/09/2008, 11:20 AM
I have only read the first page of this thread but this statement from Bean really surprises me. Bean you could not seriously believe that a 100 watt speaker heats a room just as much as a 100 watt heater. The heater is turning almost all the applied energy into heat while the speaker is turning it into a magnetic field. An MH bulb is producing much more heat than a T5 and its not just a factor of it being spread out, its also the T5 ability to more effiency create photons from applied energy with a minimal amount of power being converted to heat.
<a href=showthread.php?s=&postid=11945746#post11945746 target=_blank>Originally posted</a> by BeanAnimal
That is pretty much the definition of a Watt and exactly why we can label things with Watts and make meaningful comparisons about the energy they consume (or the heat they gice off).
A 100 watt lighbult heats the room just as much as a 100 watt heater or a 100 watt speaker. Watts are watts :) [/B]
edwarder
05/09/2008, 12:05 PM
"A watt is a watt" is true interms of the energy used by a device. What a device does with that energy is a different story. T5s appear to convert more of that energy into light rather than heat. RobbyG is correct.
RichConley
05/09/2008, 12:10 PM
<a href=showthread.php?s=&postid=12505840#post12505840 target=_blank>Originally posted</a> by RobbyG
An MH bulb is producing much more heat than a T5 and its not just a factor of it being spread out, its also the T5 ability to more effiency create photons from applied energy with a minimal amount of power being converted to heat.
First, no, the T5s aren't more efficiently creating light. See the chart.
All of the energy is converted to heat. Light hits an object, and that object is heated by the light. Energy can neither be created, nor destroyed. If 100w goes into the fixture, 100w comes out, and 100w of that energy is converted to heat (within 2 or 3 seconds). Whether the energy is initially Light, Heat, Work, etc, doesnt matter, it all becomes heat very quickly.
BreadmanMike
05/09/2008, 01:09 PM
Rich! You moved to Chicago?
RichConley
05/09/2008, 01:53 PM
As of about May 19, yeah, I will have.
BeanAnimal
05/09/2008, 02:11 PM
<a href=showthread.php?s=&postid=12505840#post12505840 target=_blank>Originally posted</a> by RobbyG
I have only read the first page of this thread but this statement from Bean really surprises me. Bean you could not seriously believe that a 100 watt speaker heats a room just as much as a 100 watt heater. It has nothing to do with belief :) It is basic physics. If 100W is drawn from the wall socket, then 100W is imparted to the room. Any sound or light that escapes the room is certainly "lost" to the outside environment, but those loses are minimal in both cases.
Now lets get to "speakers". A typical loudspeaker motor is a coil that rides in the gap of a fixed magnetic field. The setup is 10%-20% efficient at best. Most of the energy is directly converted to heat and conducted/convected away from the motor via the pole piece and the movement of air. The speaker works by compressing air, that creates friction. The sound that is produced creates vibration (heat) in the objects that it strikes.
We can talk about "magnetic fields" that escape the room, but that too is far beying the signifigance of the discussion.
Drive a speaker at 100W continuous and a lightbulb at 100W and they will both heat a given space (a calorimeter) at an equal rate and reach the same stable temperature.
As for the MH and T5 heat, the chart above tells you all you need to know. Again, with regard to directly heating the TANK water, they both radiate a very similar amount of heat. With regard to the ROOM, there is no difference, as a Watt is a Watt.
Nice to see you here Robby... don't worry I would not lead you down a path :)
hahnmeister
05/09/2008, 02:58 PM
<a href=showthread.php?s=&postid=12506190#post12506190 target=_blank>Originally posted</a> by RichConley
First, no, the T5s aren't more efficiently creating light. See the chart.
Actually, I think that might be the one area where there is some room for debate. Since the base EM output of a phosphor based bulb is in the UV range, it actually has a harder time producing warmer spectrums in many cases. Halides, dont have any 'conversion' in the same sense, but have a harder time making blue light. The exception to this might be sulfur vapor lamps (induction/plasma HID), but for the most part halides suck at blue and purple.
Being that we use mostly higher frequencies (shorter wavelengths) in our tanks... it is possible to get away with less watts of T5 than halide with bluer frequencies. This would result in a tangible reduction in heat then. Im estimating that T5s are likely to make 2x the PAR per watt of a halide in these spectrums. Not that thats ALL we need, but we do tend to rely on them more. Comparing efficiencies from the mfg's means we are most often comparing 3000K bulbs.
RichConley
05/09/2008, 03:27 PM
Hahn, that doesn't make any sense to me. Why would Halides excel at creating UV, and excel at creating yellow/green light, but suck at the light in the middle of the two?
hahnmeister
05/09/2008, 04:48 PM
Since when do Halides 'excel' at making UV? Just because they can/tend to make it, doesnt mean that they are efficient at it. If makers of HID could make a bulb that didnt give off any UV (without using a sheild), dont you think they would have done it already? I dont think its something halides are 'efficient at', nor that they can help very much. PaulErik would be a better person to ask though. For instance, phosphor lamps tend to shift and make IR after some time (or they used to), even though they dont start out like that. That doesnt mean that they are good at it. Different elements, phosphors, and halides have their peaks at different frequencies... I just dont think the one that is used for blue in halides is very efficient.
I base my conclusion on how the output of bulbs tends to drop as you go from 3000K to 20,000K. For T5s it isnt too bad, and for halides its very significant. Considering T5HO's in the 3000K range are about 85-90 lumens/watt, and halides are at best in the 105 range, it kind of evens things out, but the drop with halides is sooo significant that I think T5s have the advantage in the 20,000K range for sure.
liveforphysics
05/09/2008, 05:39 PM
Robby G- Time to learn about physics. Speaker, heater, lightbulb, chiller, computer, tv, electric motor, fan and whatever else you wish to feed 100w in a room all heat the room the same amount. They all do different things with the energy for the first instant, but it all ends up as heat in the room.
hahnmeister
05/09/2008, 07:32 PM
Well, there are exceptions. A 100w air conditioner for example, or a wall/ceiling fan; things that deal with 'outside the system'. Or, for that matter, things that make sound, radio waves, EM waves, etc... that pass through the walls of the room/house, then you really are moving energy to outside the room.
Pedro Borges
05/10/2008, 08:43 AM
Quote: [Robby G- Time to learn about physics. Speaker, heater, lightbulb, chiller, computer, tv, electric motor, fan and whatever else you wish to feed 100w in a room all heat the room the same amount. They all do different things with the energy for the first instant, but it all ends up as heat in the room.]
Well that's if the room is a theorethical blackbox without sound, heat and light export to the outside. In theory you're right, but in practice that doesn't apply since the equation is not closed as isn't the room.
But I think you are all starting to miss the point here (although the theoretical fuss was fun to read), who cares about the heat produced by the light emmitted? that's a universal truth you can't excape no matter you use MHs or T5s the key of this topic has to do with the excess heat produced by efficiency differences between the two models, what we should focus on is the amount of heat DIRECTLY produced by each of the two. And that should cover both bulbs and ballasts.
The myth of MH being hotter that T5 and the empiric statements "I changed from MH to T5 and my temperature dropped" have one very strong historical explanation: MH's are typically sold with classic ferromagnetic low efficiency ballasts and T5 are always sold with high efficient (less direct heat emmission) electronic ballasts. That allied with the also empiric observation of a MH lamp being hotter that a T5 bulb is enough to create the myth. (notice that although the MH is hotter if you touch it does not mean it produces more heat, the heat is just more concentrated because its footprint is smaller)
It all comes down to $$$ or €€€ in my case.
Better reflectors - more light towards the aquarium - less heat / lumen - less €€€
Electronic ballasts - less direct energy loss to heat - less absolute heat - less €€€
Fan off heat from your liminary - less absolute heat - more €€€
But as far as tecnologies go, the chart posted from the US department of energy says it all, they're pretty much the same.
Although you should bear in mind there are several forms of T5 and MH.
Cheers,
pjr300
05/10/2008, 12:09 PM
Pedro, that was a great post. Thanks for pulling together all the key points.
I think you raise a few great point regarding the ballast comparison usually being eBallast for T5 and magnetics for MH.
However, one question: given that many of us place the ballast in a remote location, wouldn't that make the "ballast adding heat" agruement a non factor? It would still be relevent when looking at enegery usage/efficiency, I would presume. Thoughts?
I will add one more item for the heat discussion: that HQI ballasts run bulbs hotter. In fact, Sanjay did a study several years ago and found that HQI ballasts ran SE bulbs almost 10* hotter than a standard ballast. That HQI factoid may add to the legend of hot MH...
P.S. I guess it's more than a legend. Probably more like HQI heat gives all MH systems a bad reputation... :D
Pedro Borges
05/10/2008, 07:11 PM
Hi pjr300, here in portugal its very uncommon to have the ballasts away from the bulbs, that's why I didn't mention it, in fact it's like you say, if so then it doesn't make much of a difference for heating, just for electrical consuption...
Do you have more data on that study you mentioned? Are HQI ballasts supposed to feed SEs?
When you buy a lamp you can with some trouble try and find the amount of lumens it emmits, if you compare the ratio lumen/watt in each of T5HE, T5HO, T5VHO, HQI, HCI you will find funny numbers. this gives you the efficiency of the bulb (also PAR affects that, usually high PAR bulbs have less efficiency and vice versa)
Then if you measure the consumption of the whole system and subtract the announced bulb power from the actual measured power you get the amount of energy going into heat from the whole rest of the system.
Cheers
hahnmeister
05/10/2008, 07:54 PM
There are HQI rated SE bulbs (true HQI 400's are almost all SE since there is no HQI 400 watt DE 'standard' spec). The radium 250wattSE is a HQI despite being SE. Most Ushio/BLV are as well (unless it says CWA in the model), Giesemann, Aquaconnect... the German bulbs.
Dont forget the efficiency that varies with spectrum as well, thats pehaps the biggest factor.
That being said, I thought the greatest point to take away from this is that no, 200 watts of T5 means the same amount of heat in a room or canopy as a 200 watt halide, but that as lights improve in efficiency, more efficient bulbs are used, or better reflectors are used, the whole idea is that you could get away with less watts in the first place. And then, in that case, well, nobody will argue that 100 watts of T5s is less heat than 200 watts of halide and you are just as well off if the T5s can make 2x the output per watt as the halide.
RobbyG
05/11/2008, 12:19 AM
I can agree about the T5 argument and that falls down into the line that Hahnmeister just stated but I have a hard time comparing a 100 watt speakers heat output versus a 100 watt bulb. IMO the conversion of sound energy to heat energy is just so poor that it will never generate much heat at all, even in a closed, perfectly insulated environment. But please someone point me to an article on the subject I am open to learning something new!
BTW very interesting discussion, much can be learned by all.
Pedro Borges
05/11/2008, 07:44 AM
100W of sound will generate that 100W of heat, except fot that that is hear by observers, the thing is in real worl practice it will generate those 100W of heat spread around all the area it is heard, and that's a huge amount of area...
You can load your tank with microphones all around to prevent the noise from the pumps increasing your tanks temperature hehehe, that'd be a load to watch...
Cheers,
BeanAnimal
05/11/2008, 08:28 AM
<a href=showthread.php?s=&postid=12516012#post12516012 target=_blank>Originally posted</a> by RobbyG ... but I have a hard time comparing a 100 watt speakers heat output versus a 100 watt bulb. IMO the conversion of sound energy to heat energy is just so poor that it will never generate much heat at all, even in a closed, perfectly insulated environment. But please someone point me to an article on the subject I am open to learning something new!
BTW very interesting discussion, much can be learned by all. [/B]
How (and how much) is converted is not relevant. The ENERGY passes through the speaker assembly and is shed into the box. The speaker does not store energy. So 100W in = 100W out. The box does not store energy so 100W of ENERGY in = 100W of heat.
Of course there will be some sound and megnetic field energy that escapes our imperfect box. The overall amount of energy that escapes is VERY small comapared to the whole.
Pedro Borges
05/11/2008, 09:33 AM
Well, actually most of the energy fed into the speaker will come out in the form of kinetic energy in the membrane that will in turn emmit sound waves, which are also energy.
Although you can expect a 100W speaker to heat a perfect blackbox the same as a 100W heater you won't have that effect in the real world, because the energy is spread in the form of sound through the environement and eventually change into its last heat form not in the source but in every non sound reflecting fraction of surface it reaches, so if your neightbour complains of your loud music it means part of the final 100W of heat are being produced in his house.
Same with light.
BeanAnimal
05/11/2008, 09:51 AM
<a href=showthread.php?s=&postid=12517119#post12517119 target=_blank>Originally posted</a> by Pedro Borges
Well, actually most of the energy fed into the speaker will come out in the form of kinetic energy in the membrane that will in turn emmit sound waves, which are also energy.
Although you can expect a 100W speaker to heat a perfect blackbox the same as a 100W heater you won't have that effect in the real world, because the energy is spread in the form of sound through the environment and eventually change into its last heat form not in the source but in every non sound reflecting fraction of surface it reaches, so if your neightbour complains of your loud music it means part of the final 100W of heat are being produced in his house.
Same with light.
Not really...
MOST of the energy fed into the speaker is converted directly to HEAT in the motor assembly. Secondly, the motion of the speaker cone (you called it a membrane) moves (compresses) AIR. The compression of air creates HEAT. In the context of a "speaker" system (the driver and the box) a LARGE portion of the air movement translates to FRICTION in the box stuffing and port (if it is a ported enclosure). The actual SOUND ENERGY that is spread to the environment is a VERY VERY small portion of the energy put into the system.. only few percent at best. That is why we can't use speakers (or lasers for that matter) to transport significant amounts of energy from one point to another.
Also, the fact that out "box" is not perfect has been stated dozens of times in this thread. It has little to do with the topic, as MOST of the energy is converted to HEAT in our "box" or "room".
I am not trying to be rude (so please do not take this that way), but you have entered this thread on page 6 and are pointing out (over and over) something that has been clearly stated numerous times, and doing so in a manner that suggest I (or others) may not understand. Yes, energy escapes our imperfect box. That amount of energy (for our conversation) is totally irrelevant. In the "real world" if we wanted to account for every drop of energy, we would need to quantify the sound and magnetism that escaped our box to arrive at our sum of 100W.
I think what you and several others have a fairly good understanding of the physics but are getting hung up on the "model" vs the "real world" and how much energy escapes. In any of our examples, it is a VERY small portion of the total energy put into the system. The entire point of this conversation is that for our purposes, a Watt of energy pumped into the room is a Watt of heat.
If you want to learn more about the energy transfer function of a loudspeaker (of any kind) you will want to look into the work of Thiele and Small. They worked out the math needed to define the interaction of a loudspeaker (and its associated enclosure) from a small signal perspective (large singal analysis is a different ball of wax). From their equations you can determine port velocities, driver parameters, voice coil heating, box heating, etc. Without their work, speaker system design would not be possible :)
2farNorth
05/11/2008, 10:55 AM
Just wanted to jump in and share my 2 cents worth... Esp. on the subject of the 100w objects, such as the speaker.....
Actually Bean said the same thing almost exactly as I woulda put it... And this comes with close to 20 yrs. experience...
<a href=showthread.php?s=&postid=12517184#post12517184 target=_blank>Originally posted</a> by BeanAnimal
Not really...
MOST of the energy fed into the speaker is converted directly to HEAT in the motor assembly. Secondly, the motion of the speaker cone (you called it a membrane) moves (compresses) AIR. The compression of air creates HEAT. In the context of a "speaker" system (the driver and the box) a LARGE portion of the air movement translates to FRICTION in the box stuffing and port (if it is a ported enclosure). The actual SOUND ENERGY that is spread to the environment is a VERY VERY small portion of the energy put into the system.. only few percent at best. That is why we can't use speakers (or lasers for that matter) to transport significant amounts of energy from one point to another.
Anyways, Back at the subject at hand, I personally I believe 1000w of T5 compared to 1000w of MH, the MH will run cooler because it would be easier to keep cool.... just the size if fixture to hold that many T5's compared to a couple MH pendents.... speaking watt per watt though... not efficiency... because of course 1000w of T5 would cover a much great area.... then say - 1 - 1000watt MH fixture...,, well unless you use 4- 250w MH then well......either way I would think the MH would run cooler... if both had the same cooling system, such as a single fan....
Pedro Borges
05/11/2008, 10:58 AM
No harm meant, no harm taken...
I'll take your word for the proportions of energy involved in speaker work.
For our case as you state it what exactly do you mean 1W of light energy = 1W of heat?
Let's make an example with a fixture for a 100W lamp:
It takes more than 100W from the mains, somewhere in the 110-140's for a common case scenario, this varies with the electronics of the fixture - that extra is just pure direct heat.
It does not emmit 100W of light, the bulb itself releases part of those in the form of heat, that has to do with light efficiency and in that scenario T5 and MH are pretty close to each other as the chart posted early shows.
Now you come to the amount of light emmited being finally transformed into heat and that's where I say that the same way that a tiny ammount of light energy goes into photosynthesis, the same is true for the ammount that goes into heating your rocks and fish in the water >95% of it just comes out of the aquarium still in the form of light.
But even if this last point wasn't true, its a physical phenomenon occuring after the light is produced (which is our point here no?)and so is independent of light source being T5 or MH.
Cheers,
BeanAnimal
05/11/2008, 12:06 PM
Thanks pedro (for taking the comments as discussionary, not as confrontational).
Now to the example :)
We can look at it either way "as a system" and the overall wattage that is pumped into the room or as the line "bulb" and the overall wattage that is pumped into it. To compare apples to apples, we would look at a 100W overall systems, or bulbs driven at 100W total.
A Watt is still a Watt. 100W in = 100W of heat in the room (minus the small amount that escapes via light, sound, or whatever and minus the small amount that is stored in the bio-matter).
A small portion may escape the room through a window or via magnetic fields or sound or be stored by the bio-matter in the tank.
There is no argument that there is a difference between what is HEAT in the tank and HEAT in the room. Yes, some of the energy will not be directly absorbed by the tank and instead will be imparted directly to the room.
The thread had two major topics that evolved. One was regarding the heat imparted to the tank and that evolved into a basic physics discussion of Watts and Heat with regard to the ROOM. The comments and discussion have at times intertwined the two points and I think that is where a lot of the confusion and restatement of the "model" and "reality" are coming from.
In the end, many (most) of the people who understand the physics are saying the same thing but getting stuck on the finer points due to the way the information has been presented. Those who do not understand have clouded the discussion in the process of learning and asking the already answered questions. Without a doubt somebody will drop in and say "yeah but a so and so bulb is more efficient and therefore creates less heat" and the discussion will rehatch again.
Enjoy :) and of course, thanks for trying to help people understand the physics at play.
RobbyG
05/11/2008, 10:56 PM
Bean are you a scientist locked in a research lab at Area 51 or possibly a subject held at Area 51 ?? :) My God you know a mind blowing amount about Physics, electronics etc.
I really enjoyed reading your explanation and it makes a whole lot of sense, and your right it is hard to grasp how the Model would work versus what we see in the real world. For me even though I know the theory I keep thinking that conversions of energy are going to change the outcome. Thank You for clearing it up.
sirreal63
05/12/2008, 06:02 AM
So after all this discussion...can we all agree that for the purpose of the hobby a watt is a watt and T5's are not cooler watt for watt than halides? :-)
BeanAnimal
05/12/2008, 06:13 AM
No I am not a scientist... There are just some topics of some subjects that seem to "click" with me and I understand them very clearly. My electronics knowledge is rather limited. I understand a lot of theory but have trouble putting it into practice. I have struggled for several years trying to design my OWN high power audio amplifier. I struggle with Kirchhoff's law in even simple circuits. What bugs me is that is another case of "what goes in must come out" but I go cross-eyed trying to figure out what goes where.
As for physics, most of it is pretty logical (when you remember to apply the basic laws, no matter how illogical they appear). Don't worry, I can't get paste chapeter two of any Einstien related theory!
Thanks for the kind words Robby... You knew the right answer all along, it just takes a nudge sometimes to put it all together and unknow what you thought you had down pat. Folks like yourself deserve the bigger pat on the back for keeping an open mind and putting it all together, as opposed to digging your heals in and defending opinion :)
See ya next time...
pjr300
05/12/2008, 06:17 AM
<a href=showthread.php?s=&postid=12522113#post12522113 target=_blank>Originally posted</a> by sirreal63
So after all this discussion...can we all agree that for the purpose of the hobby a watt is a watt and T5's are not cooler watt for watt than halides? :-)
what? Watt? Can't hear you with all these 100 watt speakers blaring. :D
BeanAnimal
05/12/2008, 06:51 AM
100W of pure sound energy would certainly be loud. Your average listening level from a "100W" stereo is a few watts at best :) Doubling the output power only adds 3db to the sound level. It takes 10db to effectly double the volume. So that 1000W amp is only about twice as loud as the 100W amp :) Furthermore, if that 1000W amp has a 25A fuse (we can skip the math here), it is really a 150W amp! Watts are Watts, no matter what the label on the amp says :)
styndall
05/12/2008, 07:57 AM
<a href=showthread.php?s=&postid=12522113#post12522113 target=_blank>Originally posted</a> by sirreal63
So after all this discussion...can we all agree that for the purpose of the hobby a watt is a watt and T5's are not cooler watt for watt than halides? :-)
No. There are lots of cogent objections, and the room model we've ended up talking about, while it's roughly accurate in a high school physics sort of way, doesn't capture much important about the amount of heat imparted to the tank, nor does it describe accurately the way energy can escape your room.
The temperatures are probably substantially similar in many cases, but they will definitely not be the same.
2farNorth
05/12/2008, 08:35 AM
<a href=showthread.php?s=&postid=12522113#post12522113 target=_blank>Originally posted</a> by sirreal63
So after all this discussion...can we all agree that for the purpose of the hobby a watt is a watt and T5's are not cooler watt for watt than halides? :-)
Not sure about "all" of us....
But, I believe this yes..... for the purpose of this hobby, considering were talking about 'physics' ...everything looks good in the text book (or computer now-adays) but in the 'real' world,, a little different situation.....
Maybe a 'controlled' experiment is due.... instead of arguing physics.....
Otherwise I'll stick with my $7.00 clip on fan blowing across my 250w halide set up.... which physically cost me 1/3 of what a T5 setup with the same wattage would run... and would take years to make up in efficiency.... in my experience MH's are running cooler...
sirreal63
05/12/2008, 08:52 AM
I already did the real world model...I am keeping my halides. Equivalent wattage of T5's vs halides...the halides are easier to cool. Of course I did not take into account photosynthesis which would make absolutely no difference in the heating of the tank. LOL
Styndall when you run an equivalent wattage on your tanks and see what real world actually means come back and impart to us your experience. :-)
styndall
05/12/2008, 09:35 AM
<a href=showthread.php?s=&postid=12522773#post12522773 target=_blank>Originally posted</a> by sirreal63
I already did the real world model...I am keeping my halides. Equivalent wattage of T5's vs halides...the halides are easier to cool. Of course I did not take into account photosynthesis which would make absolutely no difference in the heating of the tank. LOL
Styndall when you run an equivalent wattage on your tanks and see what real world actually means come back and impart to us your experience. :-)
Note that I'm not claiming that T5s will be cooler than halides. In some scenarios and with some setups, the halides could well be cooler. What I'm claiming is that they probably won't be the same.
HarleyDude
05/12/2008, 09:46 AM
I think what it comes down to is T5's appear cooler because of their distribution of heat, which I believe was discussed earlier in this article. I have not done a PAR test on my MH's compared to my T5's, but the T5's seem to have more consistant light. I am not saying that is a good thing either. The sun through water is inconsistant and, IMO, MH's do a better job emulating this. From what I have seen in my frag tank (where the T5's are), I have to place coral further away from the light than I would an equivalent powered MH.
BeanAnimal
05/12/2008, 10:59 AM
<a href=showthread.php?s=&postid=12522520#post12522520 target=_blank>Originally posted</a> by styndall
No. There are lots of cogent objections, and the room model we've ended up talking about, while it's roughly accurate in a high school physics sort of way, doesn't capture much important about the amount of heat imparted to the tank, nor does it describe accurately the way energy can escape your room.
The temperatures are probably substantially similar in many cases, but they will definitely not be the same.
Did I not read you directly state that you would [SIC] "readily admit when I am wrong" on another thread?
1) The "Room model" has NOTHING to do with the discussion about the two different lamps and the heat imparted to the TANK. Why do you refuse to see the context here?
2) The US DOE chart tells us a LOT about how the different light sources affect the tank temperature and allow us to make VERY meaningful comparisons between the different light sources.
3) You entered this thread with a firm statement that I was wrong. You went from that to confsuing the subjects of the room and the tank and have now digressed to admitting that I am correct, but only in a high school physics type of way. Rather funny if you ask me.
Lets see if we can recap this one more time:
We are not counting electrons and photons here, were are talking about the general fact that 100W of anything running in a room will impart 100W of heat into the room minus the small amount that escapes via different paths or forms. Your stuck trying to quantify this small amount of energy ( the stuff that radiates out a window or passes through a wall in the form of a magnetic field, the stuff that is stored by the corals escapes as sound. There is nothing "high school' about it. There is SIMPLY NO NEED to dig any deeper, as the amounts of energy and their paths of escape are 100% irrelevant to the discussion. The model fits the discussion and is only as complicated as need be to illustrate the general point and physics. If we wanted to further quantify the energy, we would need a more complex model. We simply have no need.
4)We are also not talking about the absorption rates of different materials or the number of ways that energy may escape the room before it is absorbed by the contents of the room. Radiation will more readily heat the contents of the room as opposed to convection or conduction, but air heated by the radiation will certainly escape through the ventilation system BEFORE it is absorbed by the contents of the room. We are NOT talking about the overall ENERGY of the room or its propensity to change in level. We are NOT talking about the propensity of absorption of different materials as it relates to different forms of energy. We can talk for days about the paths the energy takes, it is pointless and far beyond the scope of this conversation.
BeanAnimal
05/12/2008, 11:06 AM
<a href=showthread.php?s=&postid=12523022#post12523022 target=_blank>Originally posted</a> by styndall
Note that I'm not claiming that T5s will be cooler than halides. In some scenarios and with some setups, the halides could well be cooler. What I'm claiming is that they probably won't be the same.
Nobody did say the would be the same. It depends on many variables. The radiant energy from the two is very similar on a Watt per Watt basis. The two technologies have different spectral peaks/ratios. It is very logical to argue that different spectra may be more readily absorbed or rejected by the contents of the tank (including the water) and that certainly does make a difference. Nobody has said anything to the contrary.
However the radiant energy being nearly the same gives us a meaningful starting point that allows us to consider some of the other variables with more relevance. Variables such as surface area of the fixture, airflow around the fixture, etc.
sirreal63
05/12/2008, 11:21 AM
Bean...I am beginning to believe it is a dead horse as far as Styndall is concerned. He will not admit that he does not understand. It is a shame as I consider him to be a bright kid. As far as admitting he is wrong, I don't think he will ever do that, he made a bold statement in another thread that I was pushing bad info. about a watt being a watt and I think he will go away from the community long before he admits I was not in fact pushing bad information.
I will let it alone from here on out and not push him to admit anything. :-)
BeanAnimal
05/12/2008, 12:08 PM
Or we could digress into a conversation about Planck's law and Wien's law. We could examine the bulbs as black body radiation sources and look at the spectral intensity and wavelengths from each source. In the end we would end up simply proving the values published in the CHART that was kindly provided by the DOE... We could then apply the Stefan-Boltzmann Law to describe the transfer of energy FROM that black body to the surrounding environment. But wait, the basic form of that LAW covers IDEAL BLACK BODY radiators... hrmm we would need to apply the derived form of the law for imperfect radiation sources. We could then intermingle the simple definition of the Watt and come to the conclusion that the Law of Conservation of Energy is valid and that our silly little model gets us close enough to talk about a fish tank and a fish room.
The idea here was NOT to teach quantum physics or complex energy transfer functions, it was to help nudge people along with a basic understanding of thermodynamics and that fact that by its VERY DEFINITION we can use the word Watt to compare the ENERGY consumption and HEAT output of just about anything. When that "anything" is confined in a room, then we can make some reasonable assumptions about the heat load on the room. HVAC engineers use the same basic "model" to calculate heat loads for rooms and entire buildings.
To explain scientific concepts so that a high school educated adult can understand them does not make those subjects trivial or dumbed down. Another way to look at it, if you walk away from this thread understanding that a 100W fan and a 100W lightbult BOTH put 100W of Energy ( and therefore 100W of heat ) into a room, then your doing better than the average college graduate. If you desire is to dig deeper and understand the why and how, then you at least have a starting point because you understand the basics of thermodynamics and energy.
sirreal63
05/12/2008, 12:12 PM
Well said.
Pedro Borges
05/13/2008, 08:04 AM
But bean its an agnowledged fact that all will turn into heat, but the basic question I guess is how much the equipment turns into heat directly (counted as loss) and how much it turns into liht that will as you very well ultimately turn into heat, but that'll be out of the aquarium most of it..
So for the sake of the discussion lets keep in mind for our "real world" model that light will not turn into heat (although it does) because it is not meaningful for the purpose of the topic.
Intellectual interest at part the pure theoretical models help us little to the actual case here woun't you agree?
Cheers,
RichConley
05/13/2008, 08:25 AM
<a href=showthread.php?s=&postid=12529536#post12529536 target=_blank>Originally posted</a> by Pedro Borges
So for the sake of the discussion lets keep in mind for our "real world" model that light will not turn into heat (although it does) because it is not meaningful for the purpose of the topic.
Pedro, the problem is that all that energy goes into the room, and heats the room. This causes your tank to cool slower. All the energy affects your tank.
styndall
05/13/2008, 09:02 AM
It's not complicated. Listen to Pedro.
styndall
05/13/2008, 09:20 AM
<a href=showthread.php?s=&postid=12529646#post12529646 target=_blank>Originally posted</a> by RichConley
Pedro, the problem is that all that energy goes into the room, and heats the room. This causes your tank to cool slower. All the energy affects your tank.
Your room isn't a closed system. The extra heat will cause your AC to turn on a smidge earlier or delay the heater by a little while. It'll have considerably less effect on your tank than your thermostat setting. The point is that the "room" model here doesn't describe the amount of heat that a particular kind of light adds to a tank.
Also, to Sirreal: Smug and wrong is an unfortunate combination. A bright kid? Good grief.
Black Mammoth
05/13/2008, 11:19 AM
styndall I sent you a PM the other day. According to RC you haven't read it yet. I just wanted to give you a heads up.
OceanAV
05/13/2008, 11:24 AM
<a href=showthread.php?s=&postid=12529949#post12529949 target=_blank>Originally posted</a> by styndall
Your room isn't a closed system. The extra heat will cause your AC to turn on a smidge earlier or delay the heater by a little while. It'll have considerably less effect on your tank than your thermostat setting. The point is that the "room" model here doesn't describe the amount of heat that a particular kind of light adds to a tank.
Also, to Sirreal: Smug and wrong is an unfortunate combination. A bright kid? Good grief.
I think that the point Bean is so patiently trying to get across that ANY devices-light fixtures, heaters, fans…consuming N Watt will produce the same amount of heat. How you deal with this heat (AC, open windows, Fan, etc.) is a different topic.
sirreal63
05/13/2008, 11:48 AM
Everyone has been patient for the most part in this thread, the problem is some people have their head in the sand. :-)
Bean...you get mad props for not blowing your cool.
styndall
05/13/2008, 12:03 PM
<a href=showthread.php?s=&postid=12530642#post12530642 target=_blank>Originally posted</a> by Black Mammoth
styndall I sent you a PM the other day. According to RC you haven't read it yet. I just wanted to give you a heads up.
Hey, thanks for the heads up. I didn't see the PM until now.
GSMguy
05/13/2008, 12:15 PM
<a href=showthread.php?s=&postid=12529845#post12529845 target=_blank>Originally posted</a> by styndall
It's not complicated. Listen to Pedro.
hmpphhhh, and at the same time ignore bean and Rich Right?
Black Mammoth
05/13/2008, 12:37 PM
I think that the point Bean is so patiently trying to get across that ANY devices-light fixtures, heaters, fans…consuming N Watt will produce the same amount of heat. How you deal with this heat (AC, open windows, Fan, etc.) is a different topic.
The fact is, "Reef Central is an online community where quality information about the marine and reef aquarium hobby can be exchanged among all levels of hobbyist from beginner to advanced. Our goal is to help educate people about the saltwater aquarium hobby and enhance awareness of the fragility of coral reefs around the world. We hope you will join us and that you find this site useful."
Talking about heat about lights in the theoretical situations not applied to the tank isn't nearly as beneficial as the application to the tank. I've said it before and Bean said it before, look at the setup.
OceanAV
05/13/2008, 01:23 PM
<a href=showthread.php?s=&postid=12531147#post12531147 target=_blank>Originally posted</a> by Black Mammoth
The fact is, "Reef Central is an online community where quality information about the marine and reef aquarium hobby can be exchanged among all levels of hobbyist from beginner to advanced. Our goal is to help educate people about the saltwater aquarium hobby and enhance awareness of the fragility of coral reefs around the world. We hope you will join us and that you find this site useful."
Talking about heat about lights in the theoretical situations not applied to the tank isn't nearly as beneficial as the application to the tank. I've said it before and Bean said it before, look at the setup.
For a newb like myself it is helpful in making decision which system to buy. Most of recommendations I read here and other places say go with T5 – they run cool and use less electricity. Well, now that I went through this tread I know that it’s not always true and why. So and it was beneficial to me.;)
Gomer
05/13/2008, 01:34 PM
I have skimmed over most of this thread (not all in gory detail). A few comments.
While a system that draws 100watts from the wall as a T5 or MH is the same, our tanks are not coupled to the wall power as a system.
1) The only heat that gets into your tank is UV-IR radiation that gets absorbed. Water, our primary heating absorber, absorbs (to a first order approximation) exponentially more as you go more to the IR. So, it you have 100watts of light from a MH and 100watts of light from a T5, the tank temp will only be equal if the product of the intesity and absorption coefficient integrate to equality. If you have a T5 which generates a ton of vis and a MH that generates a ton of IR, the MH will heat the tank a ton more.
3) Light is either transmitted, absorbed or reflected. Energy into the tank reflects at different efficiencies depending on the wavelength of light and the medium it is interacting with. This is spectral dependent and T5/MH have different spectra.
3) Extreme example but important here: Suppose a 99% and a 1% efficient ballast. Both systems draw 100 watts. The 99% efficient ballast will warm the tank 99x more than the 1% ballast given all things are equal.
4) 100watts is not a 100 watts in terms of heating potential unless a system is allowed to reach equilibrium. water has a very high thermal conductivity and capacitance compared to air. Just cause you dump energy into the room does not mean it will make it into the tank.
But that is all theory. None of it matters. Comparing T5 heat to MH heating is pointless. We don't box our tanks in a sealed system. We never let it reach equilibrium.
I can put my hand under my 70watt sunpod and it will be warm. I can put my hand under a non fan cooled 70watt viper and my hand will be burning.
RobbyG
05/13/2008, 01:43 PM
In almost all real world cases the T5 will be cooler and cooler by a lot more than the MH. Now you could use a ton of fans etc to make them comparitive but that is also adding more to your electric bill. The main thing for me is that Watt for Watt you get much more PAR with T5's. I dont need charts or anything else for that one, I have seen 400W of MH and 400W of T5 and the T5 is much more brighter.
<a href=showthread.php?s=&postid=12531459#post12531459 target=_blank>Originally posted</a> by OceanAV
For a newb like myself it is helpful in making decision which system to buy. Most of recommendations I read here and other places say go with T5 – they run cool and use less electricity. Well, now that I went through this tread I know that it’s not always true and why. So and it was beneficial to me.;)
Black Mammoth
05/13/2008, 02:18 PM
For a newb like myself it is helpful in making decision which system to buy. Most of recommendations I read here and other places say go with T5 – they run cool and use less electricity. Well, now that I went through this tread I know that it’s not always true and why. So and it was beneficial to me.;)
I knew this would happen. This was my point of my original post. This thread doesn't cover how it will affect your tank directly. There are a lot more parameters that need to be covered. Some people hit on them, but not all. We even haven't hit the materials physics (or engineering) and heat transfer yet (at least fully) There is a lot more going on. That is my point of being careful on what you read.
OceanAV
05/13/2008, 02:27 PM
I’ve had 8x54 T5 running over my 75G for 2 years. Temp is stable at 80… It’s just not what I would want to see. Tank evenly filled with lots of light is not exactly what I see when I go snorkeling. To each each own I guess…
What kept me from MH so long – electrical bill and heat. I just ordered MH with 2x150MH + 4x54T5. So I will have first hand experience as to any changes in temp. My electrical bill should not be that different though.
But I appreciate your comments Black and Robby.
Gomer
05/13/2008, 02:39 PM
a little 4" computer fan on 9V will barely be a speck on the electricity bill compared to your lighting.
the amount of cooling that you'll get from a 4" fan at 9v is substantial compared to convection cooling.
sirreal63
05/13/2008, 02:46 PM
Agreed and another thing that hasn't been touched on is the ease of cooling with a higher temperature differential, which is probably why my tank runs cooler with halides that it did with T5's, the temp differential is higher which makes cooling easier.
Black Mammoth
05/13/2008, 02:47 PM
<a href=showthread.php?s=&postid=12531893#post12531893 target=_blank>Originally posted</a> by OceanAV
I’ve had 8x54 T5 running over my 75G for 2 years. Temp is stable at 80… It’s just not what I would want to see. Tank evenly filled with lots of light is not exactly what I see when I go snorkeling. To each each own I guess…
What kept me from MH so long – electrical bill and heat. I just ordered MH with 2x150MH + 4x54T5. So I will have first hand experience as to any changes in temp. My electrical bill should not be that different though.
But I appreciate your comments Black and Robby.
Wow 8x54s on your 75! I ran 4x54s on my 75 and I run 6x54s on my 90. As of recent I have been running 4x54s on my 90. I keep softies, LPS, SPS, Clams and Anenomes.
With 6x54s and the rest of the stuff in my tank, I keep it around 77 and I have to have heaters on to keep it at that temp.
styndall
05/13/2008, 03:03 PM
<a href=showthread.php?s=&postid=12531535#post12531535 target=_blank>Originally posted</a> by Gomer
I have skimmed over most of this thread (not all in gory detail). A few comments.
While a system that draws 100watts from the wall as a T5 or MH is the same, our tanks are not coupled to the wall power as a system.
1) The only heat that gets into your tank is UV-IR radiation that gets absorbed. Water, our primary heating absorber, absorbs (to a first order approximation) exponentially more as you go more to the IR. So, it you have 100watts of light from a MH and 100watts of light from a T5, the tank temp will only be equal if the product of the intesity and absorption coefficient integrate to equality. If you have a T5 which generates a ton of vis and a MH that generates a ton of IR, the MH will heat the tank a ton more.
3) Light is either transmitted, absorbed or reflected. Energy into the tank reflects at different efficiencies depending on the wavelength of light and the medium it is interacting with. This is spectral dependent and T5/MH have different spectra.
3) Extreme example but important here: Suppose a 99% and a 1% efficient ballast. Both systems draw 100 watts. The 99% efficient ballast will warm the tank 99x more than the 1% ballast given all things are equal.
4) 100watts is not a 100 watts in terms of heating potential unless a system is allowed to reach equilibrium. water has a very high thermal conductivity and capacitance compared to air. Just cause you dump energy into the room does not mean it will make it into the tank.
But that is all theory. None of it matters. Comparing T5 heat to MH heating is pointless. We don't box our tanks in a sealed system. We never let it reach equilibrium.
I can put my hand under my 70watt sunpod and it will be warm. I can put my hand under a non fan cooled 70watt viper and my hand will be burning.
This is the best post in the thread.
BeanAnimal
05/13/2008, 04:23 PM
<a href=showthread.php?s=&postid=12529536#post12529536 target=_blank>Originally posted</a> by Pedro Borges
But bean its an agnowledged fact that all will turn into heat, but the basic question I guess is how much the equipment turns into heat directly (counted as loss) and how much it turns into liht that will as you very well ultimately turn into heat, but that'll be out of the aquarium most of it..
So for the sake of the discussion lets keep in mind for our "real world" model that light will not turn into heat (although it does) because it is not meaningful for the purpose of the topic.
Intellectual interest at part the pure theoretical models help us little to the actual case here woun't you agree?
Cheers,
Goodness this is going in circles. The efficiency does not matter for the "room" model, it is all heat.
For the tank model, the radiant energy is what matters.
You are also missing the fact that NO MATTER what the light source is, VERY LITTLE of the energy is LIGHT.
Furthermore, comparing a T5 and a MH, both units will allow similar LIGHT to escape the tank, therefore the model STILL WORKS as does the CHART posted a page or so back.
There is a a lot of tail chasing here, but the facts have not changed a bit. The model I proposed for the room IS VALID in the real world. The discussions about the MH and T5 having very similar radiant energy is ALSO valid in the real world.
Please CAN WE STOP confusing the "energy heating the room" learning experience with the "what is heating the tank" conversation. The context of the two VERY DIFFERENT conversations has been confused here and it is starting to fuel irrelevant debate.
BeanAnimal
05/13/2008, 04:25 PM
<a href=showthread.php?s=&postid=12529845#post12529845 target=_blank>Originally posted</a> by styndall
It's not complicated. Listen to Pedro.
Now thats a laugh. You are the one who showed up and complicated two very simple points (facts).
2farNorth
05/13/2008, 04:27 PM
I'm still trying to figure out about the Myth,, is it busted or confirmed? :D
I say BUSTED!! ;)
BeanAnimal
05/13/2008, 04:39 PM
<a href=showthread.php?s=&postid=12531535#post12531535 target=_blank>Originally posted</a> by Gomer
I have skimmed over most of this thread (not all in gory detail). A few comments.
While a system that draws 100watts from the wall as a T5 or MH is the same, our tanks are not coupled to the wall power as a system.
1) The only heat that gets into your tank is UV-IR radiation that gets absorbed. Water, our primary heating absorber, absorbs (to a first order approximation) exponentially more as you go more to the IR. So, it you have 100watts of light from a MH and 100watts of light from a T5, the tank temp will only be equal if the product of the intesity and absorption coefficient integrate to equality. If you have a T5 which generates a ton of vis and a MH that generates a ton of IR, the MH will heat the tank a ton more.] Certainly. I don't think anybody has said anything any different. :)
3) Light is either transmitted, absorbed or reflected. Energy into the tank reflects at different efficiencies depending on the wavelength of light and the medium it is interacting with. This is spectral dependent and T5/MH have different spectra. Correct again, I think this was mentioned just a few posts back in one of my conclusions. The easy part is that the T5 and MH have very similar radiant energy. That allows us to almost directly compare them based on spectral differences. In this case the average spectral outputs are similar with the major differences being in the IR and UV spectra.
3) Extreme example but important here: Suppose a 99% and a 1% efficient ballast. Both systems draw 100 watts. The 99% efficient ballast will warm the tank 99x more than the 1% ballast given all things are equal. Exactly, that was also clearly stated several times above. The radiant energy is key with regard to the tank heating directly from the fixture. The convective heating is only secondary.
4) 100watts is not a 100 watts in terms of heating potential unless a system is allowed to reach equilibrium. water has a very high thermal conductivity and capacitance compared to air. Just cause you dump energy into the room does not mean it will make it into the tank. Also 100% true. I never stated any differently. A "hotter" room will slow the cooling of the tank though, and that is something to keep in mind, no matter what type of device we are talking about :)
But that is all theory. None of it matters. Comparing T5 heat to MH heating is pointless. We don't box our tanks in a sealed system. We never let it reach equilibrium. Again, the point of using theory here was to help people understand the basic foundations that the rest of the conversation was built on, no more. That has been made very clear a dozen times, but a few folks have insisted on putting words in mouths and trying to nit-pick the theory.
Thanks for taking the time to post gomer. Your thoughts were well articulated and certainly very correct.
BeanAnimal
05/13/2008, 04:42 PM
<a href=showthread.php?s=&postid=12531998#post12531998 target=_blank>Originally posted</a> by Gomer
a little 4" computer fan on 9V will barely be a speck on the electricity bill compared to your lighting.
the amount of cooling that you'll get from a 4" fan at 9v is substantial compared to convection cooling.
Esp if it is used to assist the convective process... The idea setup from a thermal standpoint is to have the fan pull air out the top of the canopy, but the hot humid air is hard on the fans. So the next best choise is to force feed air into the canopy from the sides and let it naturaly vent out the top. :)
BeanAnimal
05/13/2008, 04:44 PM
<a href=showthread.php?s=&postid=12532054#post12532054 target=_blank>Originally posted</a> by sirreal63
Agreed and another thing that hasn't been touched on is the ease of cooling with a higher temperature differential, which is probably why my tank runs cooler with halides that it did with T5's, the temp differential is higher which makes cooling easier.
Yes, the higher the temperature differential between two masses, the faster heat flows from the hot to the cold.
Bean
I'm still trying to figure out about the Myth,, is it busted or confirmed
I say BUSTED!!!!.
I have hands on experience, buy reading many watts is a watts from many reefers here in RC .By cutting back watts from getting better lower watts equipment i save almost $100 in electricity a month . .
I never change my MH set up just got lower watts equipment now i can enjoy my living room again it was so hot in there for years. So watts is a watts and it will transfer the heat in your environment
Black Mammoth
05/13/2008, 05:43 PM
<a href=showthread.php?s=&postid=12532845#post12532845 target=_blank>Originally posted</a> by Zoom
I say BUSTED!!!!.
Not so fast my friend! It depends on the context. If you are referring to what heats a tank more, MH or T5s? Then NOT busted.
2farNorth
05/13/2008, 06:00 PM
Well now I am confused...
Is the myth busted that MH are hotter then T5's or is the myth confirmed that MH are hotter then T5's?
I vote the MH are NOT any hotter then the T5's... so that meens Busted? :confused:
BeanAnimal
05/13/2008, 06:30 PM
2FarNorth,
The basic premise that MH heat a tank more than T5 is busted.
Both types of lamps put out very similar radiant energy. Part of the radiant energy is visible and both types of lamps are nearly even in that regard. They primarily differ in the amount UV and IR that they emit (radiate).
If you take a look at the electromagnetic spectrum you will see that IR is the the Left of Visible light and UV to the Right. Microwave (think about it) is far to the Left and X-Ray and Gamma Rays are far to the right. Would you care to guess which (IR or UV is more readily absorbed (turned to heat) by a mass. Apply your choice to the chart that I posted :)
Here lets try it:
http://www.reeflogix.com/images/rc/ledheat.jpg
The T5 is 21% visible and Metal Halide is 27% visible. Pretty close.
The T5 puts out 37% IR, that is readily absorbed (converted to heat) by the mass in the tank (including the water) as heat.
The MH Puts out 17% IR and 19% UV.
We can look at the overal visible spectral peaks and make some assumptions about the wavelengths more likely to be absorbed.. but it is kind of pointless at this level. Instead we will just assume that 50% of the visible spectrum is close to the UV and and the other 50% close to the IR end. So 11% for the T5 and 14% for the MH.
So lets add it up.. (purists, please don't go bonkers.. this is just a rough idea of what is going on). 48% for the T5 and 33% for the MH. To be nice we will include some of the UV for the halide, lets say 9%. That is 48% vs 42%. It still certainly looks like the energy from the halide has less of a chance of being absorbed in the tank. Of course you could fiddle with the numbers and come up with any number of conclusions.
The point is that both fixtures are fairly similar and that the MYTH that T5 put less heat into the tank is pretty much busted at least in terms of radiant energy.
The variables are in the actual setups and have a lot to do with air movement and other factors.
I hope that helps.
Black Mammoth
05/13/2008, 06:36 PM
The basic premise that MH heat a tank more than T5 is busted.
That contradicts what you agreed to above. With respect to heating up a tank, this myth isn't busted.
BeanAnimal
05/13/2008, 06:43 PM
With all due respect, Please point out where I have contradicted myself. I have said the same thing over and over for 9 pages. I do see plenty of areas where people have misrepresented what I and others have said and then acted like somebody else has provided new information.
This is one of the most frustrating threads I have ever participated in. The basic physics have not changed, nor has the basic statement of the facts. People keep dropping in and the whole discussion re-hatches with new people and we start over. Each time the point gets burried further in out of context remarks that are tangent to the original two points.
The first point was regarding the T5 and the MH and the overall energy (radiant and convective) into the tanks. We came to many general conclusions MANY pages back.
The second point was regarding the basics of thermodynamics and energy as it relates to any object in a room. Just basic background education for those interested in the bigger picture.
Black Mammoth
05/13/2008, 07:01 PM
Retracted my original post. I misread someone else's post which made it looked like you contradicted yourself. My apologies. However, I still disagree with the MHs and T5s heating the tank to the same temps. I disagree that rooms with tanks are closed.
BTW, I do agree with the statement about the setups.
2farNorth
05/13/2008, 07:09 PM
<a href=showthread.php?s=&postid=12533632#post12533632 target=_blank>Originally posted</a> by BeanAnimal
This is one of the most frustrating threads I have ever participated in.
Now that is the best line out of the whole thread!!!
I've been subscribed from page 2, and I was really surprised this thread popped back up....
Kinda thought the whole thing was common sense... Actually High-school educational physics... point source bulbs, reflectors, element/gas surface area, cooling systems... etc. etc.... all of it can change the outcome.... So there really isn't an true answer.... I can guarantee my MH system is alot cooler then some peoples T5 setups... and THAT I'll take to the bank...
Anyone can drag as much scientific data out of text books, and it all leads to the same thing..........
a Watt is a Watt.... just depends on how you want to use it!!!;)
Gomer
05/13/2008, 07:31 PM
I bet I can put together a 150watt LED setup that would put more light and a ton less heat into a tank then a 150watt MH with luminarc reflector ;)
2farNorth
05/13/2008, 07:38 PM
That also depends on who is setting up the MH setup.... ;)
GSMguy
05/13/2008, 07:38 PM
<a href=showthread.php?s=&postid=12533931#post12533931 target=_blank>Originally posted</a> by Gomer
I bet I can put together a 150watt LED setup that would put more light and a ton less heat into a tank then a 150watt MH with luminarc reflector ;)
ya ok...;)
kayne_21
05/13/2008, 07:48 PM
<a href=showthread.php?s=&postid=12533931#post12533931 target=_blank>Originally posted</a> by Gomer
I bet I can put together a 150watt LED setup that would put more light and a ton less heat into a tank then a 150watt MH with luminarc reflector ;)
That may be true. But under the definitions of our model they both will impart the same amount of the heat to our theoretical room ;)
From here it's more of how you deal with the heat that matters.
Gomer
05/13/2008, 07:51 PM
2farnorth, Doesn't matter who sets up the MH.
GSMguy, I don't need you to believe me :) I have plenty of hours under my belt with high power LEDs to know the result.
kayne_21, that post was in response to the chart which makes LEDs look like crap in comparison to MH
BeanAnimal
05/13/2008, 08:12 PM
<a href=showthread.php?s=&postid=12533596#post12533596 target=_blank>Originally posted</a> by Black Mammoth
That contradicts what you agreed to above. With respect to heating up a tank, this myth isn't busted.
Again, I ask you to please point out where I contradicted myself. You have merely repeated your prior statement. I have a feeling you are confused with the context of the entire thread and my postion regarding the subject.
Please read the title tof the thread. Then please read my comments throughout the entire thread. I did not agree to anything contrary to the points I have made or the facts at hand.
The "myth" that is the basis of this thread is that in general, MH lamps heat a tank more than a T5. The basic physical operating parameters indicate that the myth is simply not true. The T5 operates with a very similar radiant energy and it could be argued that it emits more more spectral energy in the easy to absorb wavelengths.
This is certainly getting more than a little silly.
BeanAnimal
05/13/2008, 08:15 PM
<a href=showthread.php?s=&postid=12533931#post12533931 target=_blank>Originally posted</a> by Gomer
I bet I can put together a 150watt LED setup that would put more light and a ton less heat into a tank then a 150watt MH with luminarc reflector ;)
Can we please leave the LEDs out of this thread? They are easy enough to talk about but deserve an entire thread of their own. We are NOT comparing PAR, PUR or effective spectral output in this thread. The LEDs have radically different operating parameters and folding them in will only confuse matters here.
Gomer
05/13/2008, 08:26 PM
Short version for everyone.
Choose any MH or T5 setup of comparable wattage. There are situations where EITHER can heat your tank more than the other.
It is a highly complicated deal if you want to nit pick at it, but when you boil it all down, a simple low power fan can make a HUGE difference with very little extra electricity consumed to a point where the heat difference isn't really a big deal.
sirreal63
05/13/2008, 08:31 PM
<a href=showthread.php?s=&postid=12533931#post12533931 target=_blank>Originally posted</a> by Gomer
I bet I can put together a 150watt LED setup that would put more light and a ton less heat into a tank then a 150watt MH with luminarc reflector ;)
Interesting...it so happens that the halides I run that allow my tank to run cooler are 150 watt bulbs in LumenArc Mini's. To my knowledge I am the only person to date who has retro'd 150's in LumenArcs. I hope it catches on....the amount of light they give my tank is amazing. :D
I know LED's also run hot and need to be actively cooled but I do not know enough about them to say they would be better. I'll keep my T5's...in the closet and my halides over my corals.
BeanAnimal
05/13/2008, 08:52 PM
<a href=showthread.php?s=&postid=12534409#post12534409 target=_blank>Originally posted</a> by Gomer
Short version for everyone.
Choose any MH or T5 setup of comparable wattage. There are situations where EITHER can heat your tank more than the other.
It is a highly complicated deal if you want to nit pick at it, but when you boil it all down, a simple low power fan can make a HUGE difference with very little extra electricity consumed to a point where the heat difference isn't really a big deal.
Yup pretty much...
Black Mammoth
05/13/2008, 10:24 PM
<a href=showthread.php?s=&postid=12534255#post12534255 target=_blank>Originally posted</a> by BeanAnimal
Again, I ask you to please point out where I contradicted myself. You have merely repeated your prior statement. I have a feeling you are confused with the context of the entire thread and my postion regarding the subject.
Reread. I retracted and apologized for misreading someone else's post.
Best Regards
Black Mammoth
05/13/2008, 10:29 PM
<a href=showthread.php?s=&postid=12534255#post12534255 target=_blank>Originally posted</a> by BeanAnimal
The "myth" that is the basis of this thread is that in general, MH lamps heat a tank more than a T5. The basic physical operating parameters indicate that the myth is simply not true. The T5 operates with a very similar radiant energy and it could be argued that it emits more more spectral energy in the easy to absorb wavelengths.
This is certainly getting more than a little silly.
There will be two points of views, period. The fact is that there are people out there that have switched back and forth between MH, T5s, and PC lighting. There are different results in temp.
2farNorth
05/14/2008, 04:51 AM
But for someone who is in the market for new lighting, whether it be their first lighting system or an upgrade, they should not believe the myth that Metal Halide lighting systems heat the tank up more then other lighting systems, which in turn would cause them to have to purchase chillers, etc.....
just depends on how they set it up....
I kinda believe that is the point that Tang Salad wanted to make when starting this thread.... He was also Sharing the "myth" as stated in another article, in another discussion forum....
It is interesting though how many experts jump in to argue their expertise or try to prove their intelligence!!
Great thread by the way!
sabbath
05/14/2008, 04:54 AM
<a href=showthread.php?s=&postid=12535230#post12535230 target=_blank>Originally posted</a> by Black Mammoth
There will be two points of views, period. The fact is that there are people out there that have switched back and forth between MH, T5s, and PC lighting. There are different results in temp.
The experience from around here is. The system that has the most efficient cooling. IE open top and a fan in the sump area. Don't run nearly as hot as any, MH or T5 with a canopy.
BeanAnimal
05/14/2008, 06:00 AM
<a href=showthread.php?s=&postid=12535230#post12535230 target=_blank>Originally posted</a> by Black Mammoth
There will be two points of views, period. The fact is that there are people out there that have switched back and forth between MH, T5s, and PC lighting. There are different results in temp.
There may be two points of "view" but that does not make them correct. The urban myth that MH are "hotter" than T5s is busted with regard to the basic operation of the lamps and their radiant output. The heat transfer is similar and the differences pretty much lie in the setup. That was the basic premise put forth by Tang Salad and it is confirmed by the science.
If you see "different results" then you can look at the details of the setup for answers. I.E treat both bulbs pretty much like equal black body radiators. Start looking at things like air movement, relative distance from the water. Reflector efficiency and overall light focus.
Black Mammoth
05/14/2008, 08:34 AM
If you see "different results" then you can look at the details of the setup for answers. I.E treat both bulbs pretty much like equal black body radiators. Start looking at things like air movement, relative distance from the water. Reflector efficiency and overall light focus.
Again, this has been my point from the beginning. So the myth isn't busted. It depends. Even the people that make the lighting systems and sell both T5s and MH make the claim that the T5 setups run cooler. So here we are again what is theoretical and real world. I don't disagree with your statement I quoted. That's what I've been saying :) People are not understanding the setup issue at all.
sirreal63
05/14/2008, 08:45 AM
The setup can make all the difference but both can equally heat a tank up the same which is the main point of the thread, watt for watt neither is cooler.
Never trust what a manufacturer's marketing department says about their product. McDonalds claims their burgers are delicious and tasty but that is far from true.
Never trust what a manufacturer's marketing department says about their product. McDonalds claims their burgers are delicious and tasty but that is far from true.
:lol: :lol: :lol: :lol: :lol:
BeanAnimal
05/14/2008, 03:51 PM
<a href=showthread.php?s=&postid=12536899#post12536899 target=_blank>Originally posted</a> by Black Mammoth
Again, this has been my point from the beginning. So the myth isn't busted.
I am not sure you understand the "myth" then :)
The "Myth" is that a MH setup is hotter than a T5 setup. Not "sometimes"
Not "depending on"
but "IS HOTTER"
It is a MYTH.
The statement was not "The Myth of MH sometimes being hotter than T5".
Please don't take this as rude, but the meaning of words is important. When we start twisting the meanings of words, then we lose the language. In this case the meaning of the word "myth" is important, as is the context it is used in :) The use of the word "Myth" when put in context with statement, allow only one scenario, that is "MHs ARE hotter than T5", Not "MH may at times be hotter than T5". There is no ambiguity in the meaning and that is partly the reason the word "myth" and the phrasing of the thread title was chosen in the first place :)
A Myth:
a: a popular belief or tradition that has grown up around something or someone;
b: an unfounded or false notion
Lets replace the word "myth" with the phrase "an unfounded or false notion" and put it into the title of the thread:
It is an unfounded or false notion that Metal Halides are hotter than T5s.
We have shown that the statement is TRUE. It is a false notion, as the opposite can easily be true.
I hope this makes sense. Sorry to be so picky, but I hate to come this far and have the entire thread and conclusion get hung up on a misinterpretation of the word "myth" or title of the thread.
RichConley
05/14/2008, 04:09 PM
<a href=showthread.php?s=&postid=12536899#post12536899 target=_blank>Originally posted</a> by Black Mammoth
Again, this has been my point from the beginning. So the myth isn't busted. It depends. Even the people that make the lighting systems and sell both T5s and MH make the claim that the T5 setups run cooler. So here we are again what is theoretical and real world. I don't disagree with your statement I quoted. That's what I've been saying :) People are not understanding the setup issue at all.
The myth IS busted. MH isn't hotter than T5.
Poorly set up lighting/cooling systems are hotter than well designed lighting/cooling systems. Whether its MH or T5 is irrelevant.
I ran 2x250w on my tank. Switched to 6x54W. Had more temperature issues. Why? MH pendants were further from the tank, and took up much less space, so I had much better air movement/cooling.
RobbyG
05/15/2008, 02:54 PM
I think the Myth and the ideal model scenario distract people from the real issue, which for me is that in a real world setup it will be much easier to get a cooler lighting system with a T5 and it will also look a heck of a lot better than seeing a MH hanging 18" above your tank or an enclosed MH running a ton of fans.
BeanAnimal
05/15/2008, 03:23 PM
I am not sure I agree with the premise.
The T5s need as many fans as the MH. Remember they both have very similar radiant energy. If we are talking about a hood type setup, then the point is moot, both setups are virtually the same. The same radiant energy is trapped between the hood and tank.
If we are talking about pendants, then the MH has a distinct advantage because it will cover much less surface area over the tank and allow for better convective and evaporative cooling. I am not sure where the notion that you would need to have it 18" obove the water comes from.
I run two 150W ReefOptix pendants about 4" from the water surface and evaporate about 5G a day. If I ran a full T5 pendant my evaporation rate would drop significantly (the heat would rise) because of the trapped air between the large pendant and the water surface.
Thoughts?
Black Mammoth
05/15/2008, 03:52 PM
The T5s need as many fans as the MH.
Thoughts?
I respectfully disagree. I have both MHs and T5s. In my experience that MHs cause more heat in my tanks. The funny thing is that I don't run any fans on my T5s, but I do on my MH. I ran fans on the T5s after hearing claims of longer bulb life, but I'm not sure if that actually true. So my tank with T5s are not cooled and I have lower temps.
I said it once before, it is in the setup. I also find it funny that lighting companies also make the same claim about the T5s running cooler than MHs and they make and sell both systems. I guess they are also falling for the myth. Additionally, the chart doesn't express T5s, it says fluorescents. Here is my point, we know that there are differences in heat between T5s and T8s even though they are the same type. What was used in that study? We don't know. I looked up the presentation from where that was taken and it does not describe it.
the chart doesn't express T5s, it says fluorescents.
Do I missing something here ? T5 are fluorescent right?
Black Mammoth
05/15/2008, 04:09 PM
<a href=showthread.php?s=&postid=12546879#post12546879 target=_blank>Originally posted</a> by Zoom
Do I missing something here ? T5 are fluorescent right?
Yes. Continue reading what I posted. I then talk about how T5s and T8s which are both fluorescents but are known to produce different levels of heat.
BeanAnimal
05/15/2008, 04:23 PM
<a href=showthread.php?s=&postid=12546779#post12546779 target=_blank>Originally posted</a> by Black Mammoth
I respectfully disagree. I have both MHs and T5s. In my experience that MHs cause more heat in my tanks. My goodness... after this entire thread, we are back to this :D
I said it once before, it is in the setup. Yes, that is what we are saying. It is in the setup. MH are NOT hotter than T5 (you just said they were again, above).
So if the SETUP is a HOOD with two very similar radiation sources, then the HEAT will be the same. Very very simple.
If the setup is pendant or fixture style, then all bets are off. It just depends on the setup. A Full fixture vs a pendant will make a difference.
I guess they are also falling for the myth. No, they are marketing. They tell consumers what they want to hear, it sells products.
Additionally, the chart doesn't express T5s, it says fluorescents. Here is my point, we know that there are differences in heat between T5s and T8s even though they are the same type. What was used in that study? We don't know. I looked up the presentation from where that was taken and it does not describe it. There are subtle difference between the different types of fluorescent lighting. Each tube type has a slightly different efficiency rating and characteristics. THe same holds true with different types of Metal Halides. The MAJOR difference between a T5 and a T12 bulb is the tube diameter and the amount of light that can be efficiently redirected via the use of a narrow SLR.
You may wish to know that the T5 HO bulbs are less efficient than the NO versions (the same for T12s. The NO are more efficient than the HO or VHO versions).
T12 NO are in the 85 l/W range
T8 NO are in the 92 l/W range
T5 NO are in the 100 l/W range
T5 HO are in the 93 l/W range.
The D.O.E. CHART above is likely talking about normal output T12 or T8 bulbs. In any case it really does not matter because they are all very similar.
2farNorth
05/15/2008, 04:24 PM
But the T8's are larger diameter, and lower wattage also....
vBulletin® v3.8.4, Copyright ©2000-2024, Jelsoft Enterprises Ltd.