I'm looking at heating a very small space, roughly 1 foot x 1 foot by 6 inches high. However this will be in a below 0 environment. I do not have electricity as an option. What can I use for something battery powered or anything else? Thanks
Heating a tiny space like this.. Why?? How about a little propane burner.. Set on low. Used to heat up my 6x8 shed with a Gas grill on high..
For a space that small you could use a candle as long as it is insulated properly. How about a flashlight? A 24V/70W incandecent lamp running off batteries charged with a solar/wind generator? It really won't take much for that small of a space.
I thought about a candle but that'd be too much of a hassle and a light would affect the thing as i need it to be pretty dark. Is there any way to make a heated cord or something to run on a battery?
you could just use a length or wire, but the size / length will be pretty critical, also it will nuke most batteries pretty quickly (we are talking minutes) so you'll need to ask yourself how hot, how long and how critical the temperature is. If you wanted to use a battery then you would probably want something like a car battery. You'll also need to pick and choose your wire carfuly. If you ignore the internal resistance of the battery then you can calculate the power output using ohms law V=IR P=VI or P=I^2R. So a hypothetical 1ohm length of wire on a 12v battery will cause 12A to flow and dissipate 144w of heat. Be warned that a 1ohm length of wire is going to be pretty long unless you use very thin wire, and thin wire is going to get pretty hot and probably melt its insulation (assume 70c operating limit for PVC insulation.) An easier alternative would be something like a car head lamp buried in some none flammable material too block out all the light, headlamps over here are normally rated for 55w which is a decent amount of heat, you could wire 2 in series to reduce the output and make the bulbs / battery last longer, but bulbs are a bit unpredictable in this sense so you'd have to experiment. As for thermostats you could probably just nick the gubbins out of a bi-metal strip type one from an old heater or wall thermostat, they are mechanical in operation so they arn't too fussy about what load / voltage they are switching.
I was having a bit more of a think about this and decided it would be much easier to just use some combination of power resistors. 12v through 15ohms will produce near enough 10w of heat, and 10w power resistors are pretty cheap so you could just run as many as you need in parallel. Or grab something bigger like a 50w, it all depends on how hot you want things.
The power resistor idea will work without giving off light. With either method you will need a source to charge the batteries and since you don't have electricity, you will need to use either a fossil fueled generator or solar/wind/water to recharge. Don't use a car battery as it can only stand a couple deep discharge/charge cycles before it is no good. A deep cycle RV/marine battery will work because they are made for deep discharge/charge cycles.
What are you building? Its 12" x 12" x 6, needs to be heated, and has to stay dark? It's a curious project. If you gave some more info about what you have in mind you may be able to get more help. As for the heat, and since electricity isn't possible, I'd suggest a remote heater, like a kerosense space heater, connected to the box via a heating duct. You can get ducting material at amy home improvement store. That will allow you to funnel a lot of heat into the confined area and you can control it externally using the heater's controls. you can even place it in an adjacent room if you need the outside of the box to stay cold for whatever reason. That's the advantage of a duct system, everything is remote. You need to make sure you insulate the duct work so you don't loose heat across the distance.
can you not put a wind turbine up? would it freeze solid? If so how about a solar panel or get a couple of hamsters in a cage and make them a turbine wheel theyll soon learn that warmth = running on their wheel then attach to the turbine wheel a light bulb
Have you considered biological sources? For example, if you bury this thing 5 feet or so it should remain at about 55 degrees F. If you need something hotter, burying it in an active compost pile would do the trick. Just ideas.
