Ravi Teja Parella
Bio: Ravi Teja Parella is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Parabolic reflector & Mass flow meter. The author has co-authored 1 publications.
••01 Jan 2020
TL;DR: In this paper, a point focus based direct solar water heating system was designed and fabricated at IIT Jodhpur to achieve a flux concentration of 100 Suns, which will enable receiver area reduction and the use of other heat transfer fluids like oil in future.
Abstract: 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.
TL;DR: In this article , the authors investigated the opto-thermal and economic assessment of low-cost solar parabolic dish concentrators (PDC), focusing on the receiver position-induced uncertainties.
Abstract: This paper investigates the opto-thermal and economic assessment of low-cost solar parabolic dish concentrators (PDC), focusing on the receiver position-induced uncertainties. An optical model of the proposed PDC system is developed in Tonatiuh optical simulation tool. The optical analysis is conducted by the Monte Carlo Ray Tracing method for different vertical and horizontal positions of the PDC’s receiver. In addition, An experimental test rig based on a locally manufactured PDC with a low-cost reflecting surface made of aluminum reflector foil is developed to achieve the purpose of this work. A cavity receiver made of a cylindrical-cone brass tube is used and tested under different positions of the focal point of the PDC. The impact of the uncertainties on the performance of the proposed PDC is experimentally estimated. A relatively simple mathematical model is utilized to evaluate the thermal and exergy performance for the different positions of the cavity receiver. The results showed that the proposed PDC could generate hot water at temperatures 77°C, 64°C, and 55°C for the three focal point positions, respectively. The collector efficiency of the PDC-cavity receiver system in the receiver position 1, 2, and 3 were 70.2%, 53.2%, and 24 % while the average values of exergy efficiency for the PDC at the receiver positions were 4.7%, 2.3%, and 0.93% respectively. This clearly shows the effect of the receiver positions on the performance of the parabolic dish solar concentrator and justifies the requirement of appropriate positioning of the receiver for the parabolic dishes.