Efficiency

The luminous tube is capable of producing UV as well as other wavelengths of light and is rebuildable. It is the only routinely rebuildable light source I am aware of. Typically a tube can last 5 to 8 years. If you are prepared with the right skills and means you can reuse materials in the lamp indefinitely. This can not be said of other light sources with the exception of carbon arc lamps, but by comparison carbon arcs are probably more resource intensive, less efficient (about 4.6% total efficiency) require high currents to operate and produce CO2 gas from the consumption of the electrodes. Just try to keep one burning 24 hours a day and see how much time you spend making electrodes and keeping the feed mechanism working. But yes, carbon arcs produce UV light.

You could try to keep a bunch of automobile headlamps working, but there again you are depending on a consumable item for your life support. You would have to be producing high current DC to keep a garden growing to keep a handful of people alive, if you are not running your lamps will give you the most useable life if they are kept burning at a steady current. Thermal cycling is death to incandescent lamps. The more you turn them off and on the fewer burning hors you get out of them. You could keep them burning and provide day/night cycles to your plants by moving the lights to different plants. There is a basic tenet of thermodynamics that says heat causes failure (I paraphrase). A light source that produces a lot of heat because of inefficiency will also experience a short life as a result of that heat. Heat is not only produced in the lamps, but in the power systems feeding the lamps because of the high current being used.

You would be better off with a lower current, higher voltage power source. It would require less infrastructure for the power produced, and will last longer with fewer problems because it is not subjected to so much heating. If you also use more efficient light sources that last longer you are left with a power and lighting system that will give you ten times the benefit for each Watt produced than the inefficient, low voltage, high current approach.

Offered by Steve