Cost Effective Domestic Solar Thermal Energy Systems for Northern Maritime Climates
Abstract
The current cost of installed solar water heating systems in the United Kingdom using accredited installers results in payback periods which can be substantially longer than the projected lifespan (25 years). This paper investigates integration of non-imaging Compound Parabolic Concentrators (CPCs) and lower cost thermal energy storage units fabricated from thermoplastics as a method for reducing the current high cost of solar water heating in the UK. Experimental results from outdoor testing of a non-evacuated flat plate solar collector incorporating a non-imaging CPCs is presented and compared to current proprietary systems. The heat removal factor (FR) and heat loss coefficient (FRUL) of a direct flow CPC solar thermal collector under an irradiance of 800W m-2 was measured as 0.52 and 1.72 W m-2 K-1 respectively. A hot water storage tank fabricated from a thermoplastic and incorporated with a solar water heater was evaluated under extended outdoor testing and its heat loss coefficient measured as 1.3W K-1 , 7.4 times lower than an installed domestic solar hot water storage unit.