Ken Peavey wrote:
I've looked at alternative energy sources and found biogas to be the one with the best potential for indoor lighting. Considering the amount of gas that would need to be consumed, there would be considerable ancillary heat produced. I've considered putting together some sort of lamp to take advantage of light and heat: A glass mantle containing the lamp topped with a metal flu. If suspended from the ceiling, a reflector can direct the lighting downward. The metal flu would aid in dissipating heat, as well as directing exhaust to a central vent. Does this make any sense?
Gas lamps of good design (inverted mantle, high pressure), can achieve 2.3 lumens per Calorie (of energy input as biogas) per hour (0.58 lumens per Btu per hour).
Compared to electric illumination, this is definitely not big potatoes. A 100-watt bulb will give 14.2 lumens per Calorie (of energy input as electricity) per hour. But even this is outclassed by fluorescent lamps, which can give up to 73 lumens per Calorie per hour. At 100% efficiency of conversion, heat into light, we would expect 721.5 lumens per Calorie per hour, so nobody can really brag.
At any rate, the light equivalent of a 100-watt bulb (using the above figures) will cost us 355 Cal (1,410 Btu) of heat energy per hour. At 5.8 Calories per liter of biogas (650 Btu per cubic foot), 100 watts of light would be obtained from 60 liters of biogas (2.2 cubic feet) burned each hour in a very good incandescent mantle lamp. This can, however, vary a great deal. One propane light was rated at 50-watts light output at a cost of 452 Cal per hour (1,800 Btu).
This is approximately a “best case” and “worst case,” and most inverted mantle manufactured natural gas or biogas lamps give light and burn gas in this range.
Joel Hollingsworth wrote:
I've thought along the same lines as Ken, but thought gas light s might do well in a greenhouse. The CO[sub]2[/sub] would also be appreciated, as well as the light and heat. But the spectrum was tweaked so that it looks balanced to the human eye. Presumably plants don't need so much green light. Do you think that would be worth exploring different sorts of mantle for use in a greenhouse?
Also, it would be nice to do without the thorium. A broken mantle shouldn't be a big deal, but if it's made of a radionuclide, I'd want to be careful.
I ask partly because I'll have my degree fairly soon, and while I don't know much about candoluminescence (the phenomenon that makes lantern mantles work), I have a fair amount of experience in several relevant fields.