Registered: 1352981942 Posts: 2,311
Reply with quote #61
I think a 3rd(middle) screen would work to a point, but how much sun will the back-most screen layer get? 20%? And if the primary heated screens are closer to the cool glazing in a shallow collector box, it might offset any gains. My screen gap testing did make me think about 3 layers when I found out how large a gap our ZP test seemed to prefer. Seatec built a 6 layer screen build that he called a ZP, but if I recall, the air had to pass through screen layers to exit the collector. Not much light was going to bounce off the back of his collector and make it out again...
Greg in MN
Registered: 1388591029 Posts: 2,877
Reply with quote #62
It was just a thought. The longer and narrower the passages are, the more power it will take to push the air through them. A wider gap with an extra screen or two should make for easier "breathing". Sure the back screen will get a bit less sun, but I think that should be more than compensated for by the middle screen. Yes it would require a thicker collector to accommodate the wider gap.
__________________ Solar is like the wind. It may be free, but putting it to work isn't! Willie, Tampa Bay
Registered: 1379269883 Posts: 261
Reply with quote #63
Thanks for the clarification, Greg. I think I got the time sequence mixed up - thought Krautman made the comment after the gap tests instead of before.