T5s vs. MH... What would be the ultimate faceoff?

[danskim]

Also I think I remember reading a while ago that he was going to release the information at this year's MACNA first?

[hahnmeister]

Originally posted by thriceanangel
OMG I can't believe that you're saying that radiant heat depends on IR! I thought for sure you knew better

From Wiki:

Heat

Main article: Thermal radiation

Infrared radiation is popularly known as "heat" or sometimes "heat radiation", since many people attribute all radiant heating to infrared light. This is a widespread misconception, since light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun only accounts for 49%[7] of the heating of the Earth, the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visible radiation. It is true that objects at room temperature will emit radiation mostly concentrated in the 8-12 micron band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see black body and Wien's displacement law)

This is a very simple concept of thermodynamics, and part and parcel to the law of thermodynamics that you quoted earlier. The light (ALL light) that doesn't get used in photosynthesis, or reflected back, gets turned into heat. You can't vent light.

Um yeah, to the guy who doesnt read before he posts: I do know better than what you said (no offense, but duh). Reread what I wrote and you will understand. I just stated that THOSE heaters in particular are IR radiant heaters. If you read the last and second to last sentences in my first paragraph you quoted, and THINK about it, to compare light radiation would be a wash... as to claim that one makes more radiant energy in this spectrum wouldnt exactly be a bad thing... the heat output would be proportional to the light output... so comparing the two technologies on that level would be a wash. If you would be claiming that the T5s create less radiant heat, well, then it would mean that watt for watt, they create less light. So comparing the radiant heat output of anything based on the visible light output is a wash... because the whole point of the fixture is to make light. You want a light that makes little to no radiant heat? Then it would be a very dim bulb.

Its a given that the radiant energy from our lights should contain little to no UV or IR, so radiant heating would consist of the same stuff we actually WANT our lights to produce. In effect, claiming that halides would be better at radiating per watt would in effect be claiming that they are more efficient light sources.

[HBtank]

Originally posted by hahnmeister
Aargh.. why didnt I think of this before...

Also, I would like to point out to HBtank that radiant heating depends on the infra red output of the source. With halides and T5s, IR is minimal with either (unless its an old bulb or something less than ideal). So unless you are using a bulb with a great deal of IR in its output, the effects of radiant heating should be minimal with T5s or halides. If radiant heating was such a large factor with either of these systems, then our tanks would be flooded with cyano feeding on IR. The only radiant output of either system should be with visible light, or 350-750nm at most. So the heat output of either source would break even with the light output regardless of the type.

I would suggest that only the convective or conductive methods of energy transfer are the options for either light system to heat the water by transferring heat through the air. So simply venting the heated air from either bulb before it touches the tank would be the most effective. With my past uses of both technologies, the T5s were more difficult to have this happen because of their closer proximity to the water. Although when I used an acrylic sheild to 'duct' the air across the bulb and out the end of the tek via fan, the heat from the T5s was greatly minimized. SImilarly though, running a halide pendant with a fan and duct to vent air outside resulted in similar dramatic drops in heat output into the tank/room.

What's your take manderx?

There are three factors to consider.

1. The efficiency of radiant heat (infared) output of the different bulbs.

2. The efficiency of non-radiant heat output of the different bulbs.

3. The efficiency of visible light output of the different bulbs.

You seem to think 1, 2 are equal between technologies, and my research said otherwise. This is not just confined to reef geeks. There are stark differences across all the technologies (incandecents, halogen, mercury vapor etc..) and 1 and 2 change depending on which is used in terms of comparing how heat is produced from watts not converted to visible light.

Basically in summation, MH produce more IR and T5 produce more non-radiant heat from the wattage not converted to visible light.

Simple as that. Combine that with an awesome reflector and you got yourself a partial heatlamp. Where as with a T5 you just got a hot-lamp.

This leads to situation where the heat can be delt with easier by cooling the lamp itself and ventilating, which is exactly what people are seeing happen. Where as with more rediant heat, the tank will be directly heated and fans are far less efficient. Here comes the chillers.

Your assertions of porportionality and cyano are lost on me.. just does not correlate with anything I have read.

"If you would be claiming that the T5s create less radiant heat, well, then it would mean that watt for watt, they create less light"

No, it means they produce MORE non-radiant heat than MH bulbs.

So, though the total quantitative heat produced may be the same between the two technologies by looking at the basic effeciency of their production of visible light, the qualitative assesment of how that heat is produced makes a huge difference in how you tank is effected and how cooling systems will perform.

BTW, LEDS had the lowest IR output and was the most efficient at producing non-radiant heat in my research.

[The Grim Reefer]

Tastes Great!

[HBtank]

Originally posted by hahnmeister

Its a given that the radiant energy from our lights should contain little to no UV or IR, so radiant heating would consist of the same stuff we actually WANT our lights to produce. In effect, claiming that halides would be better at radiating per watt would in effect be claiming that they are more efficient light sources.

Little to no UV or IR..?? A given? Since when?

I guess it is time for everyone to ditch their UV shield and give their corals a suntan

Anyways, some real links.

A good basic lighting link from the Dr's. with MH as the only technology where radiant heat is specifically stated.

"The bulbs of a metal halide system produce a large amount of heat that will both warm the air within the lighting hood as well as warm the aquarium water through its radiant heat"

http://www.peteducation.com/article....articleid=2707

Just some basic supporting verbage from the Dr's regarding my previous post.

"Lighting systems designed for reef aquariums produce two types of intense heat, which must be addressed prior to installation. The first type of heat - from the actual bulbs - surrounds the bulbs and should be removed with cooling fans. The second type of heat - radiant heat produced by the lighting system - is unavoidably absorbed by the aquarium water and should be controlled with a water chiller (be sure to budget for a water chiller in your installation plans). "

http://www.liveaquaria.com/general/g...al_pagesid=150


Some more on metal halides and radiant heat observations:

"Luminaire construction can make a profound difference in focusing of light and reflection of ultraviolet radiation and infrared radiation. The polished aluminum, possibly along with minor differences in pendent construction geometry, reflected visible radiation at a much more efficient rate than the pendent with the white paint interior. Apparently, it also reflected infrared radiation at a much higher rate (as evidenced by higher temperatures of corals kept under it)."

http://www.advancedaquarist.com/2006/2/aafeature2/view

[thriceanangel]

word

[thriceanangel]

Originally posted by hahnmeister
So unless you are using a bulb with a great deal of IR in its output, the effects of radiant heating should be minimal with T5s or halides.

Oh, OK, I took this to mean that unless you're using a bulb with a great deal of IR in it's output, the effects of radiant heating should be minimal with T5's or Halides. Duh!

So actually you were saying that that the effects of radiant heating are less dependent on IR radiation, and more dependent on the rest of the spectrum: visible and invisible. Sorry I don't know how i missed that one.

less filling... and I ought to know!

[The Grim Reefer]

Boxers!

[Labman48076]

briefs can we stay on topic guys I am excited about Sanjay and Grim Reefers work on this along with all the others that are helping. so that we can finally get real answers about t5 vs MH those that want to debate other stuff love to see a thread started about that.

[HBtank]

Boxer-briefs...

Anways, the "real answers" are in peoples tanks.

All these numbers are worthless.

[hahnmeister]

HBtank, when you look at the spectral plots of Sanjays, you will see that you can actually see the IR and UV spectrums of any bulb (or at least the 310-850nm range, which should be enough). Compared to the visible spectrums, they are minimal. Besides, its not like T5s dont put out similar amounts of IR. If there were significant levels of either, then we would have red cyano problems from the IR, and plenty of other problems from the UV. Sure, some DE bulbs might make some more UV, but thats the purpose of the LoE sheild... to capture that.

As for citing the Foster&Smith article... come on. Thats not even a valid article... thats just propaganda and observations from people who dont even know how to set up lighting in their own facility...lol. There is nothing to compare to other light forms or anything. Sure halides seemingly make alot of heat, but were going in circles now... watt for watt, they make less than any other light source out there. The perception that they are so much hotter comes from the fact that they have to shed all their heat in a 4" long, 1" diameter surface area... and T5s have about 40x the surface area per watt. IF you trapped either system inside a canopy, you would overheat your tank. Power Compacts, for instance, will make more heat than either, watt for watt. But I thought we were talking about radiant heat here, no?

I think the perception that halides make so much more radiant heat is based on the concentration of it... thats it. People hold their hand under the bulb and go 'wow, thats radiating alot of heat'... well, sure... its often times a few hundred watts of heat being generated in an area that is less than one square foot. If it was as spread out as T5s, the perception would be just as different.

Your other two sources say nothing in comparing T5s to halides... both use polished aluminum, and both radiate heat. They arent saying that one does more than the other though. Of course a very bright light, any bright light, is going to radiate heat in the form of light.

Basically, to prove that T5s make less heat than halides, you would need to find one of a few things...

1. Prove that T5s have a higher light output than halides so you need less watts in the first place. As of yet, this argument goes both ways depending on the tank and the desired spectrum.

2. Prove that T5 bulbs have less IR/radiant heat in their output than halide bulbs. As of yet, phosphor based bulbs arent exactly shy in this area any more than halides.

3. Or that somehow, the reflectors for halides are different than the ones for T5s in how they project radiant heat. I think the result so far has been that the efficiency of this is also directly related to the light output anyways, so lowering ones radiant heat output wouldnt.

Otherwise, the arguments about how much T5s heat compared to Halide is purely one of convection and conduction through the air. Both systems are effectively equal in this respect, only that T5s take up more surface area, so the more passive the cooling systems are that are being compared, the T5s will transfer more heat to the tank.

Manderx has already backed that one up, and I know a few more that can as well including Sanjay. Back in the beginning of this recent argument, the issue was brought up because some people claimed that their T5 systems were cooler than, or heated their tanks less than, their halides. I just wanted to make it clear that this is not an accurate comparison of the technologies... thats all. Spreading out 200 watts of heat over 3 or 4 square feet vs. 1 square foot is the only difference. They both generate about the same amount of heat. What Im sure is more to account for the different experiences is the built in cooling solutions that many T5 systems come with, or that the individual just didnt use active cooling in an equally effective way with the halides before.

[hahnmeister]

Originally posted by thriceanangel
Oh, OK, I took this to mean that unless you're using a bulb with a great deal of IR in it's output, the effects of radiant heating should be minimal with T5's or Halides. Duh!

So actually you were saying that that the effects of radiant heating are less dependent on IR radiation, and more dependent on the rest of the spectrum: visible and invisible. Sorry I don't know how i missed that one.

less filling... and I ought to know!

Yes, I did say that, but in the sentences after I thought I was clear enough (as clear as I can get this late at night). It would be impossible to combine all the sentences in that paragraph into one. I just meant that 'in comparison' the two technologies could only vary in IR as far as radiant heating would be concerned. Any other claims with visible spectrums would be a wash because the only other radiation would be visible light... so to get less radiant heat per watt with either would also mean getting less light... not exactly a winning argument for either technology more than the other.

There... I think that made better sense.

But the whole idea that halides 'radiate' more than T5s seems to be nothing more than a myth otherwise... well... unless we are talking about a halide that just plain makes more light per watt or something.

[thriceanangel]

Yes that did make a bit more sense.

I think that at least in part the missing element in the quotient is the UV radiation which is going to add quite a bit of heat out of the MH as far as radiant heating goes. Which as I understand is quite substantial. I mean there aren't any warnings telling me that if the safety glass is broken on the T5's that I can get severe sunburns.

As far as this thread goes, at least we are keeping up a discussion. Sanjay hasn't been on here since January I think, and most everything else has been Sanjay do this, test this, be sure to include this, when can we get the results. C'mon, who wants to read that?

[barjam]

What are you guys talking about? Our lights put out tons and tons of IR. Just point a FLIR at your fixture and tell me it isn't the highest source of IR in the room =)

Guys, the physics here are pretty clear cut. A well designed T5 unit will heat the tank less than a well designed MH unit for a number of reasons.

Things to consider, bulk of the fixture, exposed surface area of fixture, volume of air above the tank, relative temperature difference, convection from the water's surface, air acting as an crude insulator, etc.

On top of that people don't replace 500 watts of MH with 500 watts of T5, they replace with far less as T5s are more efficient at putting light into the water than MH. Han, you even said as much in one of your posts.

[HBtank]

I think the assertion that all lighting forms have the same effeciency in producing radiant heat and non-radiant heat is the much harder claim to stomach.


Yet you keep throwing the burden of proof back at me. Where is yours?

Originally posted by hahnmeister
so to get less radiant heat per watt with either would also mean getting less light... .

No, as I said before, it would mean producing more non-radiant heat.

It seems to me that you are the only one going in circles. Back to comparing surface areas and making simple qualatative observations.

Anyways, I might pull up the links when I have time. But I have seen nothing in you resposes that really demand the effort.

[HBtank]

Originally posted by barjam
What are you guys talking about? Our lights put out tons and tons of IR. Just point a FLIR at your fixture and tell me it isn't the highest source of IR in the room =)

Guys, the physics here are pretty clear cut. A well designed T5 unit will heat the tank less than a well designed MH unit for a number of reasons.

Things to consider, bulk of the fixture, exposed surface area of fixture, volume of air above the tank, relative temperature difference, convection from the water's surface, air acting as an crude insulator, etc.

On top of that people don't replace 500 watts of MH with 500 watts of T5, they replace with far less as T5s are more efficient at putting light into the water than MH. Han, you even said as much in one of your posts.

I was adding the difference in radiant heat and non-radiant heat per watt as a "thing to consider" between the technologies. This seems to be a big facotr in how the tanks are heated by lights.

Your factors only really deal with non-radiant heat, excpet for air volume, specifically the volume between the water and the fixture..

How much radiant heat the tank directly absorbes is really a function of distance through that volume. Though fans help to pull the heat back out by evaporation.

[hahnmeister]

Originally posted by HBtank
I think the assertion that all lighting forms have the same effeciency in producing radiant heat and non-radiant heat is the much harder claim to stomach.


Yet you keep throwing the burden of proof back at me. Where is yours?



No, as I said before, it would mean producing more non-radiant heat.

It seems to me that you are the only one going in circles. Back to comparing surface areas and making simple qualatative observations.

Anyways, I might pull up the links when I have time. But I have seen nothing in you resposes that really demand the effort.

I dont have to provide any proof to negate an argument when you havent provided any proof to support it in the first place. Just like debate in highschool... if the positive team doesnt provide any info, thats all the negative team has to point out and they win. In your other response (not to me) you even pointed out that how much radiant heat the tank directly absorbes is really a function of distance through that volume. Well... then wouldnt halide have a huge advantage over T5s? T5s would be lesser distance after all.

Im not going in circles... I was just recapping. Ill go back though> To prove that halides provide radiant heating more than T5s watt for watt, comparing visible spectrums isnt really useful, since thats what we are trying to get in the first place... so comparing those spectrums is a wash. So that leaves us with other frequencies... X-ray, Gamma, etc... now, of all those other frequencies, the only ones that either T5 or halide should be able to produce is IR and UV. The UV of either should be minimal, as with halides there is the sheild (converting to conductive or convective heat, so its no longer radiant), and with T5s, well... lets just say that if there was a significant amount of UV with either, we would be having alot of problems besides heat. So that leaves IR. Now, you can go on Sanjay's site and have the IR output of any halide up to the 850nm range. And its not like phosphor based bulbs dont put out IR either. But if either put out a significant amount, then we would have other problems... red cyano and other IR loving organisms that would flood our tanks if high levels were present.

[hahnmeister]

dp

[hahnmeister]

Originally posted by barjam
What are you guys talking about? Our lights put out tons and tons of IR. Just point a FLIR at your fixture and tell me it isn't the highest source of IR in the room =)

Guys, the physics here are pretty clear cut. A well designed T5 unit will heat the tank less than a well designed MH unit for a number of reasons.

Things to consider, bulk of the fixture, exposed surface area of fixture, volume of air above the tank, relative temperature difference, convection from the water's surface, air acting as an crude insulator, etc.

On top of that people don't replace 500 watts of MH with 500 watts of T5, they replace with far less as T5s are more efficient at putting light into the water than MH. Han, you even said as much in one of your posts.

Um, I can point an IR cam at my Tek and its red just like a halide... dont know what your point is there. Sure, the halide is more concentrated, but the T5 fixture is pretty close in its output... just larger area. But an IR cam is a different system. I can point the IR cam at my head and it shows me putting out IR. This doesnt say much.

The physics is pretty clear cut. Put a 250watt halide and a 250wattT5 system in a calorimeter, and see what happens. Yep... they will both heat up to the same level. I dont think anyone here is debating that... and thats pretty clear cut.

Good point about the 500watts of halide vs the 500watts of T5... although you may not be thinking of the details. I have always pointed out that it depends on the tank, and what you want to do with it. If you want a bluer tank, then yes, T5s will most likely make the tank brighter with less light. If we are comparing daylight bulbs, then a 10,000K halide will kill a T5 setup. Comparing the two system's light output depends on alot of things though. T5s CAN be more efficient at putting their light into the water... depends on the tank. T5s tend to have a better spread than halides, and more penetration due to this. Halides will have higher peaks up closer to the bulbs that T5s just will never hit.

Lets say we are comparing on a big tank like Sanjay's... I think its a wash either way. He would need something like 1200watts of T5s to replace his 1200 watts of halides, and considering he is using 10,000Kish bulbs... he might actually need more watts of T5 to compete with his halide output.

[HBtank]

Originally posted by hahnmeister
I dont have to provide any proof to negate an argument when you havent provided any proof to support it in the first place. Just like debate in highschool... if the positive team doesnt provide any info, thats all the negative team has to point out and they win. In your other response (not to me) you even pointed out that how much radiant heat the tank directly absorbes is really a function of distance through that volume. Well... then wouldnt halide have a huge advantage over T5s? T5s would be lesser distance after all.

Im not going in circles... I was just recapping. Ill go back though> To prove that halides provide radiant heating more than T5s watt for watt, comparing visible spectrums isnt really useful, since thats what we are trying to get in the first place... so comparing those spectrums is a wash. So that leaves us with other frequencies... X-ray, Gamma, etc... now, of all those other frequencies, the only ones that either T5 or halide should be able to produce is IR and UV. The UV of either should be minimal, as with halides there is the sheild (converting to conductive or convective heat, so its no longer radiant), and with T5s, well... lets just say that if there was a significant amount of UV with either, we would be having alot of problems besides heat. So that leaves IR. Now, you can go on Sanjay's site and have the IR output of any halide up to the 850nm range. And its not like phosphor based bulbs dont put out IR either. But if either put out a significant amount, then we would have other problems... red cyano and other IR loving organisms that would flood our tanks if high levels were present.

Up to 850nm is only a ridiculously small portion of the IR spectrum. Also, you keep bringing up cyano and it is really irrelevant as well, that would also only be a tiny portion of the near-infared spectrum that bacteria can use. Not to mention other bilogical factors.

"And its not like phosphor based bulbs dont put out IR either."

I never said they did not, just less IR. More of their inefficiency is produced as non-radiant heat.

[Sanjay]

While you guys are debating.. you might find this information, published by the Department of Energy in one of their pamphlets, interesting. I am not sure whose arguments it will back up , you can argue that too




sanjay.

[HBtank]

Thanks Sanjay. Sorry for cluttering your thread...

My numbers were off between the two technologies. Quite a reversal from what I thought.

But it DOES sum up the differences I was stating there does exist between technologies, even though they were wrong.

Now to modify my argument, of course, it's all about surface area and intensity

So:

.17 x 250 = 42.5 watts

.37 x 250 = 92.5 watts

Though the MH has less than half the watts in IR, it is over a much smaller area.

Lets say the MH is 1' by 1' and the T5 is 4' x 1.5'

So:

MH is 42.4 watts of IR per square foot

T5 is 15.4 watts of IR per square foot

So...the greater intensity of the MH IR allows the IR to travel a greater distances through any given air volume....

So the question is, even though T5's have a higher total wattage, is the intesity reduced to a point where less of that total IR wattage reaches the tank at the distances T5's are commonly kept above tanks??

Or maybe it is exactly a wash... lol I have a headache.

Who want to construct the equation?

[hahnmeister]

Thanks for the factual info Sanjay... ROFL.

HBtank... please dont take this the wrong way... Im laughing with you on this one... but...

Ha ha ha hooo hooo hooo hee hee hee, x3, and ROFL.

Its just amazing when things go exactly the opposite of what you were expecting. That one caught me off guard as well. I know phosphor based systems werent exactly shy on IR, but I was thinking they were about the same... not that T5s or linear would be double... wow.

But hey, it does show that radiant energy is about the same.

But to now change your argument to the smaller area conducting more... and somehow that halides intensity is much greater or something because of concentration... well... I dont know how to treat that one. Sure, halides are more concentrated, but they also use a smaller area. So if we go back (what, a page or two now?) it goes back to my old argument that halides leave more space for cooling because they occupy less surface area of the water. Simply put, I think that the physics would show that the smaller area would transmit less... have to double check on that, but I believe its just like comparing T5s to halides with respect to their dispersion fields... the T5s light travels farther because they are more spread out.

I agree with your last statement though 100%. Like I mentioned, in my own personal experiences, the T5s heated up the tank more than the halide. All the data that Sanjay has provided backs up what I was saying 100%... its not that T5s are cooler, or that halides are cooler... they are really very similar in heat output... the T5s just more spread out, and the halides more concentrated. Its what you do with that fixture/bulb that makes the difference.

I do wonder if those results are based on SE only, and if DE + sheild would vary things much. I remember the displays that some wondow mfg's used years ago to introduce LoE glass (which is what many DE pendants use for sheilds). There would be two identical tungsten bulbs, with two identical radiometers, and one glass panel would be clear, and the other LoE. The radiometer on the LoE would barely spin, and the other would spin like mad. I was going to bring this up in the comparison... that DE bulbs at least (which is 90% of my experience with halides) would seemingly transmit very little radiant energy based on this. But Sanjay's info makes this a mute point.

[HBtank]

Ok, I admit, I only found data on incandecent and halogen versus flourecent IR and based my "theory" on the fact there were differences between technologies, not what the exact numbers were. Obviously I guessed wrong on the numbers between MH and T5

Anyways, without building a crazy reefgeek equation that factors distances, surface areas.. etc... there is no single "answer"

It seems the point is that every situation really IS different and there is no simple answer.

Just calling them equal watt for watt in heating tanks would make the most sense.

This is why I love reefing, I end up learning/researching so much usefull information. Talking about IR just reels the ladies in...

[thriceanangel]

Yummy!