PFO LED lighting

[midgetwaiter]

Originally Posted by StirCrazy

because of the efficiency the will be less heat, but how much we don't know.. I do know the luxton stars get so hot they need a heat shield to prevent the LED from burning out and I can only imagine that a 5 watt version would need that also sense a 1 watt version does. so there will be heat thrown out. now sense they use 40% less energy then you are looking at a heat difference of 40% (at least) but how much of this was through the ballast? I would say 1/2 sense I know how hot my ballast get. light is radiation of energy which when comes in contact with a surface will change to heat, the question is how much. weather you have 250 watts of radiant light from a MH or 250 watts of radiant light from and LED it is still the same amount of energy (assuming 100% efficiency) and will have the exact warming effect. now I am only taking about the radiant component, not the convection or conduction types. Convection is the big one that we have a problem with in closed hoods but can be solved with power venting, but you can vent all you want and Radiant heating will not be affected.


so like I said before.. will it run cooler, probably... how much... don't know.

Steve

You don't need heat sinks on luxeon stars because of the amount of heat they produce alone, you need it because of the amount heat it produces compared to the surface area of the device.

The radiant heat transferred by the photons striking a surface is not a significant concern and will almost completely be nullified by evaporation at the water's surface.

The amount of problem heat generated by lighting in aquariums will always be proportional of the efficiency of the light source and the water will be heated by convection. I don't care how many fans you put it a hood with two 150 watt HID lamps, the temperature in the hood will be significantly higher than ambient. Air is a shitty heat conductor and pushing it around with fans doesn't work very well. For example, this is why big transformers are submerged in oil.

Ideally you should be able to touch the surface of one of those LEDs at full power and not hurt yourself. I suspect that either PFO will manage to maintain that kind of surface temp or that the lamp life will suffer significantly. A hot LED is not a happy LED.