I will stump you with this quesion.

[Anonymous]

Okay, i'm sure that there is a simple answer but here goes.

How is it that MH lighting produces more light the PCs watt for watt. MHs emitt more light and more heat than PCs when you have two bulbs of the same wattage. But wattage is a unit of energy (joule/sec) so you can measure it with the amount of heat and light that is emitted. The MH bulb obviously consumes more electricity/energy. What gives?

 

[Anonymous]

Ballast

 

[Anonymous]

because.

 

[Anonymous]

I don't know enough to get technical with you, but MH is a completely different animal, there's an element in there, a different gas, balast...MH's also produce more light watt for watt then regular incadenscent bulbs.

 

[Anonymous]

>...MHs emitt more light and more heat than PCs when you have two bulbs of the same wattage.

Not true, so that should take care of your concern.

But if you want a more detail answer, I think others have mentioned it. It is not a apple/apple comparsion due to the use of different ballast and lighting technology. If the ballast is identical then it is possible for the CF to be neck to neck with MH if the physical characteristic is optimized. For example, by using a smaller diameter tube, and the use of better phosphor, CF can be more efficient in producing light than MH.

With same amount of watt/energy, there is strict accounting that you can do for the amount of heat and light. If they don't adds up, there is somehting wrong with your math or science or the measurement.

 

[Whodoo]

Sure did stump me....

 

[Anonymous]

Look at this chart from mge.com

So metal halide bulbs provide comparable lumens per watt to flourescent bulbs, maybe a little more. The also burn hotter, that part is obvious. So since they are more effiecient at producing light, I would think that they should also produce less heat, which is really just a waste of energy for pure lighting applications.

But.. it also could be because heat is also a type of light - electromagnetic radiation in the infrared spectrum. Maybe that is what is confusing me.

 

[ChrisRD]

What you have to consider is that the halide is producing all of its light and heat from a very small, concentrated area. Fluorescent lamps generate light and heat over much larger surface areas. The fluorescent lamps could actually be generating more overall heat but not feel as hot when you put your hand near them.

 

[Anonymous]

The fluorescent lamps could actually be generating more overall heat but not feel as hot when you put your hand near them.

Good point. But that does not explain the higher increase in temperature of tanks over metal halide lighting as opposed to PCs if PCs actually produced more overall heat.

 

[ChrisRD]

But that does not explain the higher increase in temperature of tanks over metal halide lighting as opposed to PCs if PCs actually produced more overall heat.

Although it's a common misconception in the hobby, a tank will NOT necessarily run hotter with halides vs. PCs - way too many variables involved for such a general statement to have any validity. In fact, many have had just the opposite experience. For example, I've seen several people swap out 4 X 96 watt PCs or 4 X 110 watt VHOs for a 2 X 175 watt halide setup and end-up with slightly lower power consumption, LESS heat, and a brighter tank.

 

[Anonymous]

>...But.. it also could be because heat is also a type of light - electromagnetic radiation in the infrared spectrum. Maybe that is what is confusing me.

Everything emits IR radiation, unless it is near absolute zero, like some of the interstellar space. The part of IR that heats up the water is near-IR, and both CP and MH emits a lot of it.

As Chris mentioned, the heat in MH is more concentrated due to the size of the inner bulb. If you compare the amount of heat due to same amount of lighting wattage, you will see the CF will heat up the tank more than MH. At one time, I have more than 800W of MH on a 60 gal tank, and to do that with CF won't be possible due to the surface area limitation. The reason MH *seem* to have more heat issue is because generally reefer pack a lot of wattage with MH than what is possible with CF setup.

It maybe a bit of contradictory to what I said above, but I feel that MH emit a lot more near-IR than CF (I have to compare spectra to confirm this). In the case of CF, lot of heat is lost by convection. Hopefully, I don't confuse you, but just want to say that it is not an easy relationship due to the issue of distribution of spectral power by each lamp type.

 

[Dewman]

Top 5 Reasons MH Lighting Produces More Light than Other types Of Bulbs.

1. Aliens came down from space... and gave us MH lighting.

2. It's MAGICAL. 8O

3. It's always just the way it's been around here. Don't go trying to stir things up!!

4. Agitator!!!!

5. Because

Sorry, I stole #5 from RANGER (but it was just that good)


I am truly sorry I didn't have anything constructive to add to this thread, but my post numbers are low, and I have been a member for like...well 5 years, and, I am taking copius amounts of Vicodin for the pain in my hand and it's after midnight here and I feel GREAT!! :twisted:

 

[Anonymous]

Top 5 Reasons MH Lighting Produces More Light than Other types Of Bulbs.

1. Aliens came down from space... and gave us MH lighting.

2. It's MAGICAL. 8O

3. It's always just the way it's been around here. Don't go trying to stir things up!!

4. Agitator!!!!

5. Because

Sorry, I stole #5 from RANGER (but it was just that good)


I am truly sorry I didn't have anything constructive to add to this thread, but my post numbers are low, and I have been a member for like...well 5 years, and, I am taking copius amounts of Vicodin for the pain in my hand and it's after midnight here and I feel GREAT!! :twisted:

I'm sure that Vicodin had something to do with your GREAT feeling. :wink:

 

[Anonymous]

[
Good point. But that does not explain the higher increase in temperature of tanks over metal halide lighting as opposed to PCs if PCs actually produced more overall heat.

Tank heating comes primarly from the light energy entering it and NOT the ambient temperature of the bulb.

 

[Anonymous]

Really?
So if I have a 150 w bulb right above the water on one tank, and a 400 w bulb moved significantly further away from the tank to obtain the same light intensity as the tank with the 150...both tanks will heat up just as much?

I'm not refuting you, this is not my territory...but these bulbs DO function as rather efficient heat elements, light aside. Your contention seems to contradict my real life experience.

Please elaborate.

Jim

 

[Anonymous]

Posted: Thu Aug 24, 2006 10:42 am Post subject:

--------------------------------------------------------------------------------

Really?
So if I have a 150 w bulb right above the water on one tank, and a 400 w bulb moved significantly further away from the tank to obtain the same light intensity as the tank with the 150...both tanks will heat up just as much?

I'm not refuting you, this is not my territory...but these bulbs DO function as rather efficient heat elements, light aside. Your contention seems to contradict my real life experience.

Please elaborate.

Jim

i hate to be contradictory, but i would say 'no' to that.

if you move if further away, convective heating would be reduced. i'm not sure that it would have any effect, but it might.

also, light is transmitted better that heat, so the heat would not be able to 'reach'.

sorry for the oh so technical terms used there, but i have a hangover, i'm stuck in the office, and i am finding it difficult to consentrate on difficult things

 

[Anonymous]

Really?
So if I have a 150 w bulb right above the water on one tank, and a 400 w bulb moved significantly further away from the tank to obtain the same light intensity as the tank with the 150...both tanks will heat up just as much?

That's a bit of a tricky question as worded, because a 400w bulb would need to be significantly further away than a 150w bulb to have the same intensity, and I would say that the tank heat would not be significantly different.

But to change things up again, if you go with a lower par for 400w ie 20000k (read-inefficient) bulb that was 400w, and a higher par for 250w ie 6500k (more efficient) 250w bulb, but because of the wattage difference they end up being the same PAR rating and same distance from the tank, then absolutely the 400w will heat the water more. I'm not saying that the heat due to the bulbs does not affect the temperature of the tank at all, I'm just saying that it affects it less than the light energy.

Now of course there are ALWAYS some exceptions to the rule, if you have a bunch of bulbs inside of a canopy that isn't ventellated well, then absolutely that temperature of the air in the canopy will be more of an issue than in a case where you have say pendants hanging above the tank in an open room. There are a multitude of setups that can give different results, but its the light energy itself that more effectively heats the water than any thermal "heater" heating.

I've seen this first hand, I had a 38g tank in a room with a southern facing window, directly sunlight right into the tank, the tank itself got up to 90F even though the room temp was 80, and the heat from the "bulb" was too far away to make any difference. Easiest way to test this theory though is to run an experiment... paint a bulb black or something so that it doesn't make any light, but it will heat up (I wouldn't advise this with MH bulbs, PC bulbs maybe though), test the tank water, then put a glass or acrylic pane over the tank and blow a fan across it (so the glass doesn't heat up from the bulb) this way only light "heat" enters the tank. You should see that the second case will increase the tank temp a bit more than the first.

 

[Anonymous]

Ok then...thanks.

 

[fishinsouthga]

my R2 unit has a bad motivator, anyone know how to fix that?

 

[Anonymous]

I'm still not convinced that flourscents emit more heat than MH's. :?