When I picked up my lamp yesterday, the guy running the place talked to me about heat. I got a 400W MH. He said that the average incadesant use its wattage to make about 50% light/50% heat. So, a 100 watt incadesant light produces 50Watts of heat. According to him, the MH was 80% effecient, leaving about 20% of its wattage as heat. That would be about 80 watts of heat, so about the same amount of heat that a 150 watt incadesant would put out.
While there is heat produced by the MH, it should not be hard to vent with large, slow (=quiet) fans.
Ken
While there is heat produced by the MH, it should not be hard to vent with large, slow (=quiet) fans.
Ken
I allways thought incadesant ratio was more like 5% light / 95% heat.
While MH should be more efficient, I have no idea what their ratio is but if your guy is exactly as wrong (in my eyes) as with the incadesant it should be 8% light / 92% heat.
So a 400W MH should produce about 400W of heat. 370W for the lamp and lets say 30W because the ballast isn't 100% efficient (it gets warm).
It is still possible to cool with (1) large slow fan though; If you allow your components to become hot enough, heat exchange becomes more and more efficient.
So who is wrong ?
While MH should be more efficient, I have no idea what their ratio is but if your guy is exactly as wrong (in my eyes) as with the incadesant it should be 8% light / 92% heat.
So a 400W MH should produce about 400W of heat. 370W for the lamp and lets say 30W because the ballast isn't 100% efficient (it gets warm).
It is still possible to cool with (1) large slow fan though; If you allow your components to become hot enough, heat exchange becomes more and more efficient.
So who is wrong ?
Actually, I looked under Google today and found a site that said 100W incadesant is 10% light, 75% radiated heat, 10% fixture heat loss. Halegons were similar. The MH stats only included the 40% light figure, no figure on the amount of radiated heat or UV.
So a 100 watt incadescent is 90 watts of total heat. A 400 watt MH is potentially 240 watts of heat. 4x90= 360watts of heat for 400 watts of incadescent. Based on this ratio, 400watts of I is much hotter than 400 watts of MH.
Several websites indicated the following stats. MH is 3 to 4 times more light output that a halogen bulb. Using that figure, a halogen with the proper integrated reflector would beat a bare MH of equavalent watts, but a MH with a decent reflector would smoke a halogen every time with much less heat load.
So, I think it would take 16 100w Incadescent/halogen bulbs to equal the light output of a 400 watt MH.
Ken
So a 100 watt incadescent is 90 watts of total heat. A 400 watt MH is potentially 240 watts of heat. 4x90= 360watts of heat for 400 watts of incadescent. Based on this ratio, 400watts of I is much hotter than 400 watts of MH.
Several websites indicated the following stats. MH is 3 to 4 times more light output that a halogen bulb. Using that figure, a halogen with the proper integrated reflector would beat a bare MH of equavalent watts, but a MH with a decent reflector would smoke a halogen every time with much less heat load.
So, I think it would take 16 100w Incadescent/halogen bulbs to equal the light output of a 400 watt MH.
Ken
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