Is that an image of the 80%? The 90% that I've seen has more material and less holes. I'm thinking of making a hot air collector with that as a pass-through absorber. Allows low fan wattage as it isn't pushing through something ridiculous like a bunch of cut up aluminum cans. Granted those work but it's not going to get the most heat out and will require high static to move enough air. I'm thinking low wattage 12v bilge blower or possibly even a low sone energy star rated bathroom fan with it configured to push into the panel. I might just rip out one of my cheap ceiling shaker bathroom fans for testing this prior to spending cash on such a fan. Especially if I think I'm going to want a second 4x8 DIY air heating panel.
What would the output of a 4x8 sheet collector be at a northern latitude(top US states) would you figure? I'm hoping for close to 5000BTU/hr in the 11pm-1pm window on the clear direct sun days.
Ignore the dip between noon and 1pm, every day has that since this fall, I think a tree is growing into the solar path of the device.
According to that Jan 4th 2013 Solar Radiance detail in my area on a clear day there is about 487 watts per SquaM at noon and about 450 at 11pm and just after the 1pm 'dip'.
I could add all of the numbers up but I won't at the moment, just trying to figure peak values for now. We can average about 462 watts against a 3.5556 SquaM surface in my Minneapolish area to give 1642.7 watts to the exposure. 5604.9 BTU/hr. I'm figuring I'll probably lose about 20% from windwashing the glass and get 4483BTU/hr for the peak two hours of the day? Not shabby.
OP: You meant solar air heat, right? I meant to do this in the fall using a table saw at my brothers place but he had already tucked it into the shed so a car could fit in that space for when snow was going to fall so I was a tad too late to build the frame.