T5 cooler than Compact?

[Bigmike]

Is my thinking that T5s are better for a nano tank correct? Im looking to put about 4-5 8W T5s over a 3 gal as opposed to two 18W compacts. I want sufficient light without heating my water too much. Will the T5 setup keep my water cooler and produce as good of strength lighting? I always thought that T5s were slightly more intense than compacts and ran a little cooler, is this correct?

Any input would be great! thanks

Mike

[mr pink floyd]

basically watts = heat. whether its 8 watts of T5, or 8 watts of PC, its the same heat. The difference is in intensity, so the idea is you can use less watts of T5, to get more light than PC, less wattage = less heat.

in an easier way to understand, you can probably get away with 2,8W T5 tubes, and keep most things, as long as water is stable. To get the saem PAR(light) youd need say 2x18 watts of PC

16 watts of heat opposed to 26 watts of heat.

[Bigmike]

ah... so I was on the right path in thinking... I can lower the wattage of T5 and still achieve what I want. Thanks

[exigency]

uh, i would say t5s produce much less heat than PCs no matter what wattage.. i've got a 13w pc light for my fuge and it runs way hotter than my 48w T5 HO retro for my display, i even have a fan running in the back for the PCs too.

[cschwaj]

My EE degree tells me that the watts = heat theory doesn't hold up. Watts (volts x amps) are a measure of the energy used by the bulb. The bulb can use that energy however it wants, light or heat.

The fact that T5s produce more light per watt is a testament to their efficiency and explains why thay are better than CFs. So, they use more of their energy to produce light and less goes to waste heat. This is why you can use less wattage to achieve similar output without having additional heat issues.

A simple analogy is the common household lightbulb. The watts are a measure of the energy used. 2 different 60 watt bulbs can have different lumen outpt. These get hot because they are inefficient. A compact floresent that uses significantly less power (13W, I believe) has a similar output and is cool to the touch.

I hope this helps.

[Bigmike]

Thanks for clearifying... I was kinda thinking that, but wanted to make sure... by any means, T5=better

[ykwan]

Originally posted by Bigmike
Is my thinking that T5s are better for a nano tank correct? Im looking to put about 4-5 8W T5s over a 3 gal as opposed to two 18W compacts. I want sufficient light without heating my water too much. Will the T5 setup keep my water cooler and produce as good of strength lighting? I always thought that T5s were slightly more intense than compacts and ran a little cooler, is this correct?

Any input would be great! thanks

Mike

where are u getting these lights, i want to place t5 on my 10g and i dont find any appropriate sizes (20"). and how are the pars for these small T5?

thanks

[shred5]

Originally posted by cschwaj
My EE degree tells me that the watts = heat theory doesn't hold up. Watts (volts x amps) are a measure of the energy used by the bulb. The bulb can use that energy however it wants, light or heat.

The fact that T5s produce more light per watt is a testament to their efficiency and explains why thay are better than CFs. So, they use more of their energy to produce light and less goes to waste heat. This is why you can use less wattage to achieve similar output without having additional heat issues.

A simple analogy is the common household lightbulb. The watts are a measure of the energy used. 2 different 60 watt bulbs can have different lumen outpt. These get hot because they are inefficient. A compact floresent that uses significantly less power (13W, I believe) has a similar output and is cool to the touch.

I hope this helps.

Actually I think Mr pink floyd may be right. Light is bassically heat. The difference is in the shape of the lamp and its ability to disperse heat.

Dave

[hypertech]

Sorry, I don't think light is heat. Certain parts of the spectrum will heat things (infrared I think), but my gut says the majority of heat produced by bulbs of this spectrum has to be because of the inefficiencies of the method used to convert the electrical energy to light energy.

My MSEE tells me cschwaj has this one right.

[DiViNeLeFT]

as shred5 stated, its the shape of the bulb that makes the difference... most PC's are T5... 5/8 inch diameter. the ones i use are T6 or 6/8th (3/4 inch diameter)... they are just a U shape which makes them more difficult to cool and reflect light than a straight bulb, making the straight bulb we reffer to as T5 much more efficient at the same or less watts used.

[shred5]

Originally posted by hypertech
Sorry, I don't think light is heat. Certain parts of the spectrum will heat things (infrared I think), but my gut says the majority of heat produced by bulbs of this spectrum has to be because of the inefficiencies of the method used to convert the electrical energy to light energy.

My MSEE tells me cschwaj has this one right.

Light is energy. In the form of energy we use for lighting our tanks is electricity. Lights we use in our tanks are the heating of metal (filament) and gasses.

Dave

[cschwaj]

Light is light. It is not energy or heat. Energy is necessary to produce light or heat. Light and/or heat can be captured and stored (again) as energy.

A bulb and all of its supporting and sub-components are designed to convert energy into light by manipulating the activity of electrons. The manipulation is designed to producer the intensity and spectrum of light we need for our aquariums. All devices are inhearantly inefficient. That inefficiency is what causes heat. The heat is an undesireable byproduct.

Some examples:

The sun is a nuclear reactor that produces lots of energy. Light and heat are its byproducts and are really unrelated to each other.

LEDs are efficient. They produce lots of light and little heat. They use little energy becaude there is not much waste heat produced.

[b0wenj]

I saw this thread a while back and was tempted to say something but never did....now that is has come back around I feel compelled to say in my Electronics class we have always been told Resistance = heat.

For example ........baseboard heaters get red hot and use alot of electricity because of the massive amount of resistance. They are just big resistors.

[SFMMcoasters]

I agree with what some guy said up there- Where are you finding these 8 watt T-5 bulbs?

[cschwaj]

The 8W T5s (they might even be T4s) are the bulbs that are meant to fit a strip light for a 2.5G tank (12" fixture) . I have seen them at Petsmart and a couple of the LFS. I believe they are 50/50 spectrum.

I have never seen another fixture or retro kit that uses them, though. You might have to gut the strip light for the components.

[safemode]

OK, here we go.
your bulbs convert electrical energy into heat. It's a complete process. That's why all the energy used by the bulb is heat energy eventually. I'll explain how.

The problem is the definition of heat and light. Heat is radiated from the bulb in the form of infrared light. (infrared light is radiated by the energy given off by the movement of atoms in the originating material, which is what everyone thinks of when they think of heat) Visible light is of course radiated in the same manner, different wavelength. So everything coming out of the bulb is the same, it's all "light". We're only concerned with a certain range of wavelengths though, so we call the percentage of light energy that is within that wavelength range the "efficiency" of the bulb. This is what we care about when we talk about various bulbs. How much of the light is usable light, and how much is waste light (infrared).

Now back to the how come wattage in always equals same wattage as heat. Well, we start out with a given amount of infrared light already, so that's already dealt with. The remaining wattage is light in the visible useful spectrum we care about.

This light goes off and hits atoms and molecules (air, water, corals, sand etc) and as it does so, imparts energy to those things, which produces heat in those things it hits. It bounces off those things and hits other things until it reaches 0.

The sum of the heat now given off by everything it hit is the remaining wattage from the input wattage and the initial infrared output wattage of the bulb.

incadescents are 5% efficient, that means for a 100watt bulb, 5 watts are in the visible spectrum, 95 watts are infrared, right off the bat. A 100watt CF would be putting out 15 watts of visible spectrum, and 85 watts of infrared. This is the ratings we see being advertised. The whole physics and thermodynamics shpeel about watts == heat refers to what i said that happens with the visible spectrum's energy...eventually it all turns into heat. otherwise you'd never be able to turn off a light.

[safemode]

Another way to think of it is like this. Heat as you know is the movement of atoms, aka kinetic energy. We want light energy, all kinetic energy eventually radiates in the form of infrared light though. Which is why i ignored mentioning kinetic energy before...but it helps explain the discrepancies in ideas.

So, all light output will eventually lead to kinetic energy in atoms, aka heat. All heat radiates infrared light. A filament bulb (which is a resistor), will convert most of its energy to kinetic, which means most of it's light output will be infrared. The 5% that isn't will impart it's energy in everything it hits in the form of kinetic energy a little bit at a time until it's all used up. Hence, all energy in == heat out. The engineers are talking about "systems". Aquarium builders aren't concerned with the whole thermodynamic system their bulb is in, they only care about a few pieces of that "system", hence the idea that energy in == heat doesn't mean much. The visible useful light wont turn into heat inside their tank, not completely, so it can be safely ignored as a heat source. Plus, that light energy is utilized in biochemical reactions needed in the system, heat energy can't be used in many of those reactions, as they depend on the wavelength of light, and infrared just doesn't work.


ok, so rant over. T5's are more efficient, though i would think that space restrictions may make them less viable than PC lights that can put more wattage in less length (sure more heat too, but you may not have an alternative for a given intensity of light for a given amount of space)

[Slakker]

T5's put out higher PAR value at lower wattage than CF.

[cherubfish pair]

Light is the flow of photons in the visible spectrum. Heat is the flow of photons in the infrared wavelength.

Household bulbs are 2% light and 98% heat, very inefficient compared to our aquarium lights.

Just my 2 cents.