Experimental investigation on solar photovoltaic thermal water collectors and its performance prediction using cognitive models

Abstract

Energy obtained from the principal energy source the sun is known as solar energy. A device which converts such solar energy into useful mean is known as solar energy conversion device (SECD). Solar photovoltaic (PV) module is an SECD which converts the solar energy into the electrical energy. But the performance of the solar PV module is more sensitive to its operating temperature. Direct contact cooling and indirect contact cooling are the two methods proposed by the researchers to maintain the operating temperature of the PV module. Among which the indirect contact cooling is mainly investigated by the majority of PV module cooling based researchers. Such researchers proposed a device (solar PV/T water collector) in which the solar PV module is integrated with a cooling system (indirect type). The geometry of the cooling system is in the form of tubes through which a heat transfer fluid with significant thermal conductivity is allowed to flow. Such fluid conducts the heat from the rear side of the PV module through the convection mode of heat transfer via the absorber sheet. In this project, the performance improvement of such solar PV/T water collector is attempted by increasing the rate of heat transfer between the rear side of PV module and the heat transfer fluid through the riser tube. For this, the conventional contact surface length between the riser tube and the PV module is increased. A newly configured solar PV/T water collector with increased contact surface length is designed and fabricated. Performance of such newly designed solar PV/T water collector is compared with the conventionally available collector of the same occupied area. Such comparison is conducted in the form of six different cases (three conventional and three newly configured) such as conventional stand-alone solar PV/T water collector (C-SA-SPV/T-WC), newly configured stand-alone solar PV/T water collector (NC-SA-SPV/T-WC), conventional series-connected solar PV/T water collector(C-SC-SPV/T-WC), newly configured series-connected solar PV/T water collector (NC-SC-SPV/T-WC), conventional parallelconnected solar PV/T water collector (C-PC-SPV/T-WC), and newly configured parallel-connected solar PV/T water collector (NC-PC-SPV/T-WC). Initially, experiments are conducted between C-SA-SPV/T-WC and NC-SA-SPV/T-WC system for four continuous days at Saranathan College of Engineering, Tiruchirappalli, India. For the same occupied area, NC-SA-SPV/T-WC with increased contact surface length produced a higher power output than the C-SA-SPV/T-WC system. Stand-alone experiments are followed by investigating the effects of increasing contact surface length further with the conventional seriesconnected rig. In this phase, experiments are conducted between C-SC-SPV/T-WC and NC-SC-SPV/T-WC system for four continuous days individually for C-SC-SPV/T-WC and NC-SC-SPV/T-WC system. For the same occupied area, NC-SA-SPV/T-WC with increased contact surface length produced a higher power output than the C-SC-SPV/T-WC system. newline