That said, if you don't go with the premade absorber sheets, its hard to DIY a collector that is as good as a good commercial flat plate. But, its not really efficiency that matters as much as dollars per BTU -- if the collectors are cheap enough you can just use more area to offset the slightly lower efficiency.
GaryGary gary@BuildItSolar.com www.BuildItSolar.com[ Parent ]
They give collector output for Categories A through E -- categories C and D would be typical of winter space heating applications. When comparing two different collectors, you have to be careful to divide the heat output listed by the collector area to get an output per sqft.
The section on each collector labeled "Collector Materials" makes it clear what kind of collector it is.
A bit more on using SRCC stuff: http://www.builditsolar.com/References/Ratings/SRCCRating.htm
The calculator that I mentioned in the post above allows you to enter a specific set of weather conditions, and and a particular collector -- it then gives you the heat output per sqft and the efficiency. You can run it for different types of collectors to see how well each works. The data it uses is right out of the SRCC ratings directory mentioned above.
When you do these comparisons, look at weather for your whole heating season. In our area, a significant fraction of the benefit comes in the fall and spring when we are still heating, but the conditions are milder.
Gary Gary gary@BuildItSolar.com www.BuildItSolar.com[ Parent ]
