How can I power a small heater

Re: How can I power a small heater

Your best bet would not to use Solar PV Panels to generate electricity for heating but to use thermal solar panels instead.

Solar Photo Voltaic Panels cost about $5 per watt... Thermal Solar Panels cost about $0.50 per watt--so you can get 10x the amount of heat for the same price using thermal panels. Also, you would need about 1/5 the roof space for thermal collectors as equivalent Solar PV panels. People also can build their own solar thermal collectors too pretty successfully.

There are water, antifreeze, and air based units for thermal collectors. The liquid based can use electric water heaters to store the heat (for domestic hot water, or stored heat release). The hot air types can be vented directly to the room to heat--some folks use an insulated room of water barrels or rocks to store heat for later use (used a bit in the southwest, have not heard of people using in New England).

Using batteries to store electricity for heating is also not very cost efficient (your average "car sized" storage battery would reliably only run your 1,500 watt electric heater for 20 minutes--and at that high discharge rate for one battery, it probably only last a few months before needing replacement)...

Of course, throwing money can "solve" any problem... But take a look at thermal collectors first--and remember, you ideally need good solid sun from about 9-3pm on a sort-of south facing collector. Other orientations will work, but you would need larger collectors to collect the same energy. And, if you are in a coastal region with lots of clouds/fog/winter shading from trees/buildings/mountains, you will collect much less energy.

Comments? Questions?

-Bill

Re: How can I power a small heater

I should also add, for room heating, home built can also be a very good way to go...

I can't find the link now, but one guy did a very neat solution for his barn/shop for warming his shop during the day... Basically (from memory, use the solar rules below to confirm the numbers):

1. 8' Insulated wall, south facing
2. Build a, roughly 3"-4" false wall with a piece of black metal--corrugated tin?-- at 1.5-2"
3. Cover outside with clear corrugated fiberglass and seal.
4. Cut 5"x15" "duct holes" with screens in top/bottom of wall/solar heater to allow circulating air from room to panel to room.
5. On inside upper openings, staple top of light plastic on inside wall over screen to make a "check valve".

Here is a link to somebody who built a simple solar collector for a mobile home wall (interestingly, I could not find any comments on how well it worked:

http://www.mobilehomerepair.com/article17solar.htm
http://www.mobilehomerepair.com/solarrules.htm (nice set of design rules for solar heater)

Here looks like a good reference link for solar:

http://www.nrel.gov/learning/fr_passive_solar_heating.html

And here is a nice article on solar heat and heat storage (rock, water, phase change) from Purdue University:

http://www.ces.purdue.edu/extmedia/AE/AE-89.html

-Bill