hot air collector with polyester absorber

[4acrefarm]

I just completed my first hot air collector. I used black polyester felt as an absorber behind a 6.5ft x 32 in glass door. the air flows through the felt. It is a convection system at this point, but a pv fan may be added later. I got the felt idea from " build it solar" It was a joy to work with compared to metal, and looks better too. Lets hope it works. I will let you know.

 

[SolarAndWood]

That's pretty cool. Do you think the concept could be adapted to use inside a window? I'm thinking of a decent looking panel I can install on the inside of my south facing glass in the winter that generates heat while reducing heat loss.

 

[BucksCoBernie]

looks great. I tried building one of those last winter. Mine was designed to fit inside on the window sill but it didnt work well. i cut a lot of corners w material and that was probably the reason why.

keep us updated!

 

[SolarAndWood]

cant get more heat than the sun provides. raising temp near glass will increase heatloss thru glass to outdoor & might make the thermal glass seal leak.
looks inane. not so if installed on wall instead of glass door. it is installed in an existing glass door,eh? or am i misreading.

I was thinking more like the solar sheet...flap at the bottom and top to move the heat generated during the day. Then, close the flaps when the sun goes down to reduce heat loss.

 

[4acrefarm]

does anyone have sizing information and source for pv panel and fan setup? I was thinking of dual 4" in the top duct.

 

[4acrefarm]

it is a collector built on side of house, glassing is sliding glass door.

 

[jebatty]

Isn't trying to do this on an existing window at best a 0 sum game and at worst actually a negative heat gain, as mentioned above? Doesn't 100% of the solar energy passing through the window result in absorption by whatever is in the house already? And once the solar energy passes through the glass and warms a surface somewhere, the resulting IR energy is pretty well blocked from passing back through the glass to the outside. Witness, a hot car parked in the sun.

 

[SolarAndWood]

The problem is the hot car in the sun on a winters day gets cold that night. As long as you can move the heat into the living space to avoid superheating the air near the window, it would seem that one would be able to "insulate" the windows to near wall values without giving up the solar gain.

 

[4acrefarm]

I agree with the comment on the window as a zero sum gain. let the sun shine in and warm the walls and floors, and shut the drapes at night.

 

[Delta-T]

I would think that the black felt would have a greater ability to convert IR to heat because it woudl fract/reflect less than lighter colored material. Adding a trasparent film between the glass and felt may provide for better insulation against heat mitigating through glass (darn those rules of thermodynamics). Net gain ?? I dunno. I like your experiment none the less. I wonder if a black area rug resting in full sun might do the same?