DIY solar colector?

Hi everybody!

Along thoses lines, http://www.builditsolar.com/Experimental/AirColTesting/BackpassCol/TestingFirstGo.htm, i have two questions.

First, is it possible to do the same type of colector without glass? the steel would be the first surface to be hit by sun rays, and it would have a thermostat shuting the flow. I'm thinking about doing this as a whole roof in the future. Would be vented inside with a fan in the winter. I have a lot of sun where i live. But it's way cold too. 1500m high, ski resort in the southern french alps. And in the sumer, it would be vented outside, doing the air extraction of the house. The intake into the house would be through a canadian well.

Secondly, i 'm looking to make a "normal" one, to heat up my flat. South facing flat, 36 square meters, about 93 cubic meters. I can use the front wall no prob. I have a 4 inch tube coming into the house, for air intake. What kind of surface should i need? It goes down to minus 25C° at night one month to two month of teh year. Obviously, this will be backed up by an accumulation electric heater, and à rocket. Would a 5 ish square meter colector be any good?

Fourth question, for the black part of the colector, do i absolutely need aluminium? Or steel would do? I have access to lots of roofing steel.

Update.

According to this



I'm in a place with around 1500+ kwh per square meter per year. Horizontaly from Grenoble, right on the Italian border. How much can i extract from this?

Thanks a lot and best regards.

Max.

A glass covering has 2 advantages.
1-It encloses the collector. This creates a confined space with static air-a fine insulator, and removes light breezes that can draw off energy.
2-It promotes the greenhouse effect-the conversion of shorter wavelengths into long wavelengths: heat.

You can build without the glass, but performance will be reduced.

Aluminum has a higher thermal transfer coefficient than steel or galvanized steel. Steel roofing will still work, just not as efficiently.

Hi Ken, thanks a lot for the reply.


I have bumped onto this.

http://www.solarsponge.com/

Just makes me wonder if it's worth my time.

Tho, i'm prety much in this case

"Talking with some US developers I gather that the vertical wall mounted passive heaters are really really good. If you have area below your window then I would recommend trying a passive wall heater where the hot air rises naturally out the top and into the window under convection . Actually you don't need a window, just a large wall with a hole in it.
No fans losses, little ducting losses, little radiative losses out front of the panel (due to it being vertical), and pretty much most of the heat gets into the house. Small fans can be used to supplement this though.
Very cheap to make too I've heard."

I have a 4 inch air intake just below the window. And a south facing wall below that, with some 2m50 above the ground. and two shuter hooks to hang it from

These box heaters are impressively effective. Easy to construct, cheap materials, heats a room all day.