solar thermal heating

[GaryGary]

I think i know what was confusing me.
The screen collectors will slow the air allowing it to heat up and then with the fans they will pull the air through the unit.

Units such as the can and soffit units, heat up the can/soffit and in return the air that is traveling around them.
(i have heard some people not able to get temps as hot because the air flow is down.)

So on the unit with the screens, does it need a fan? or does the fan give more air flow which in turn gives a better heat return....or am I still confused...lol

You can use the screen type absorber in collectors with or without a fan. If there is no fan than you need a lot of inlet and outlet area. Basically the only think that drives the air through these collectors is that the air heat up in the collector, becomes less dense because of the heating and just rises out the top outlet vents on the collector. The heated air leaving pull new cool air into the bottom vents. These collectors can work quite well, but you have to follow the rules on collector depth and area of the vents very carefully because anything that adds air resistance will slow the flow and make them inefficient. I don't think you will want to put that much vent area in -- basically it would have to be a slot about 4 inches high across the width of the collector wall -- one down by the floor and one at the top of the collector -- don't think the wife would like that
My barn collector is a no fan, thermosyphon screen collector:
$350 Solar Heating Thermosyphon Collector

You can use screen collectors with a fan to force the airflow. In this case, the vents can be much smaller and they don't have to be distributed all the way across the width of the collector. This is probably what you want to do.

Gary

 

[mmurphy]

That's me

Gary

:welcome: Nice thread going here. I spend a lot of time seeing what you have going on over at Build It Solar. Thanks for the research and advice you inform us on.

 

[GaryGary]

:welcome: Nice thread going here. I spend a lot of time seeing what you have going on over at Build It Solar. Thanks for the research and advice you inform us on.

Well, I figure someday I'm going to need some help with my tractor, which I know next to nothing about -- I'm building up points
Its a Ford/New Holland 2120.

Gary