Performance Analysis and Optimization of Fresnel Lens Concentrated Solar Water Heater

Abstract

Concentrated solar power (CSP) is a mature and efficient technology to cater the large-scale demand of hot water. Conventional reflectors/mirrors in CSP share 50% of total system cost. High installation as well as O&M cost is the major concern in reflector-based CSP. Apart from the above, manufacturing defects and adverse service environment cause premature degradation of reflectors and substantial drop in efficiency and service life. Performance analysis of an innovative optically concentrated solar water heater (OCSWH) using plurality of Fresnel lenses of poly methyl methacrylate (PMMA) is presented in the work. Size and yield of any solar water heater (SWH) are mainly dependent on its aperture area, output temperature, and mass flow rate, which are termed herein as critical parameters. Series of experimentations is carried out by varying critical design and operating parameters viz. aperture area, outlet temperature, and rate of mass flow, and similar experimentation is also carried out on commercially available flat plate SWH to compare its performance. Loss of heat from riser and header pipes is restricted by application of effective insulation. Substantial improvement in collector efficiency, increase in rate of mass flow, and rise in discharge temperature with reference to flat plate collector are noted. Economics is also studied covering life cycle cost (LCC), life cycle saving (LCS), and energy payback period.