Design and Development of a Concentrated Solar Water Heating System

Solar energy is a promising renewable source to support the growing energy demand. This energy is widely harnessed for solar water heating systems to provide hot water for both domestic and industrial sectors thus reducing use of conventional energy sources. In this work, a concentrated solar water heater (CSWH) system is designed and fabricated at IIT Jodhpur. The main objectives are development of a point focus based direct solar water heating system and preliminary experiment based evaluation of the designed system. The system envisages a flux concentration of 100 Suns, which will enable receiver area reduction and the use of other heat transfer fluids like oil in future. The CSWH system consists of (a) receiver and (b) parabolic dish with two-axis sun tracking provision. In the conventional solar water heater system the irradiance from sun is directly collected by the collector whereas in concentrated solar water heater the reflected irradiance is received by the receiver. The reflector consists of a reflecting surface mounted on a parabolic structure and the cavity receiver consists of consists of a serpentine copper tube exposed to concentrated irradiance. The receiver will be insulated from top in order to prevent heat loss from one of its surface. An optical model of parabolic dish and receiver has been developed using TracePro software. This model is used as reference to generate the flux density distribution. The experimental setup consists of a parabolic dish, a receiver with thermocouples, a Coriolis flow meter, pump, water tank and NI DAQ. Coriolis flow meter is used to measure the mass flow rate in the system. K-type thermocouples are attached on to the receiver and the temperature is recorded using NI DAQ system. The theoretical geometric concentration ratio predicted is 115 but from the experiment a flux concentration ratio 94 is measured.