Comments on: Solar Air Heater #3 – The Sponge http://greenterrafirma.com/wordpress/solar-air-heater-3-the-sponge/ Common sense, sustainable suggestions & DIY projects to reduce your impact on mother earth. Thu, 17 May 2012 14:26:05 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Jared http://greenterrafirma.com/wordpress/solar-air-heater-3-the-sponge/comment-page-1/#comment-1032 Jared Fri, 29 Jan 2010 21:13:23 +0000 http://greenterrafirma.com/wordpress/?p=151#comment-1032 I think the solar sponge design uses some good materials. Aluminum is definitely at the top of the list for materials for the absorber plate. I guess polycarbonate sheeting can compete with glass for transmissivity but will it become cloudy over time I wonder? It is a good idea to add obstructions in the panel to channel the flow of air all over the collector surface but this means the air will have a lot of time to warm up. Therefore, you must also increase the CFM of your fan so that you can extract the maximum amount of heat from your panel. If you panel is producing very hot air, you can be sure it is not running at its highest efficiency and based on the graphs shown on the solar sponge this is the case here. So I think this heater could be improved by increasing the fan power or altering the obstructions to lower the air resistance of the collector. I would be curious to see what effect these changes would have on the outlet temperature, air volume and overall efficiency. I incorporated some of these techniques in my own collector shown here... http://practicallyoffthegrid.com/2010/01/solarairheater1/ This collector has been working really well and produces a high volume of outlet air below 30C so I know it is operating as efficiently as possible. I think the solar sponge design uses some good materials. Aluminum is definitely at the top of the list for materials for the absorber plate. I guess polycarbonate sheeting can compete with glass for transmissivity but will it become cloudy over time I wonder?

It is a good idea to add obstructions in the panel to channel the flow of air all over the collector surface but this means the air will have a lot of time to warm up. Therefore, you must also increase the CFM of your fan so that you can extract the maximum amount of heat from your panel. If you panel is producing very hot air, you can be sure it is not running at its highest efficiency and based on the graphs shown on the solar sponge this is the case here.

So I think this heater could be improved by increasing the fan power or altering the obstructions to lower the air resistance of the collector. I would be curious to see what effect these changes would have on the outlet temperature, air volume and overall efficiency. I incorporated some of these techniques in my own collector shown here…

http://practicallyoffthegrid.com/2010/01/solarairheater1/

This collector has been working really well and produces a high volume of outlet air below 30C so I know it is operating as efficiently as possible.

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