Solar Thermal Design and efficiency?
I have finished building and testing my diy solar thermal collector. i decided to paint the outside framework black, will this make a difference? also i was wondering how to work out the efficiency and power it can produce? the temperature difference was 17 deg going in and 29 going out at a flow rate of .36 litres a minute and the solar radiation was 800 watts per m^2. the temp difference might seem low and there a 2 reasons for this. 1)im in ireland and 2)i never bled the radiator so i have a feeling the water only flew across the bottom rather than circulate.