Air to air Solar heat exchanger ! “free heat”
I have watched numerous you tube videos on air exchange Solar collectors.
I have one comment not enough air exchange happening.
When solar heating a pool, the goal is for a two degree rise in water temperature per pass.
Why ? To allow for simple, cost effective panels with little or no re radiation loss.
Most all of these videos insist on high temperature insulation and show high heat levels.
IMO and in my solar experience you should not need expensive high temperature insulation..
The reason is simple, when you are transferring the heat from the collector efficiently the collector does not get hot. I see no reason for the collector to ever rise above 90 degrees F.
Glazing and insulation in colder climates will be required, for a properly constructed collector. UV protected materials are a a must!
In Summer,the same collector vented to the outside air will prevent heat collected by the panel from entering the building.
Size the fan correctly use an adequate solar panel to drive your fan and use your Solar device year round.