February 9, 2009 Irish company Surface Power has launched what it claims is the world’s most efficient solar hot water panel. A report from Silicon Republic states that certification by testing house TUV Rhineland has shown that the innovative product is up to 131% more efficient in morning and evening time and 76% more efficient at midday than other panels.
Surface Power estimates that the product, which has undergone six years of development, has the potential to reduce domestic and commercial hot water bills by up to 70% if insulation standards meet new building regulations.
Unlike the more familiar flat plate solar collectors evacuated tube solar collectors use sets of long double walled glass vacuum evacuated tubes connected to a manifold with a small copper tip inside each tube. A tiny amount of water sealed in each tube is heated by the sun, producing superheated steam which rises to the top of the tube and heats the copper tip. The water to be heated runs past all the copper tips in the tubes via the manifold and then flows down to the storage tank below. The vacuum acts like a thermos flask, retailing up to 97% of the thermal energy resulting in increased efficiency.
Australian Company Hills Solar might contest that claim as they have tested their evacuated solar collectors at up to 163.5% more efficient per m2 over a flat plate solar collector in Australian conditions.