With the price of fuel oil going the way it is I have decided to build a solar/radiant system for part of the house. I've got most of it figured out, but have a question on the panel design.
I have a bunch of 1/2" copper pipe (free) that I'm going to use to make the collector with aand I'm not sure which design would actually collect/tranfer more heat to water/glycol circulating through the pipe. Here are the two choices
(1)Get a piece of sheet steal lay flat in insulated box,paint it flat black and then fasten lenths of copper pipe to it flush to collect the heat.
(2)Instead of sheet steel for backing use a mirrored surface for backing and raise pipe 2 or 3 inches off the surface.
In both cases I have enough pipe to make a 3'X 5' collector with the pipes spaced 6" from each other. Pipe would also be painted flat black.
I would think that the second method would collect more as the pipe would be getting either direct or reflected sunlight from all sides. Also if I cradled the pipe in lets say 1" angle iron from the back side would the increased surface area help? Angle iron would also be black
Is my thinking along the right lines or would it make that much difference? The second method would be more costly and also more time consuming, so I'm wondering if the extra work will pay off.
Thank in advance Wildbill