Keywords: solar ponds, energy efficiency, exergy efficiency, collection efficiency, thermal energy storage, transmissivity, absorptivity, solar exergy, exergy destruction, second law analysis, thermodynamics, energy analysis, exergy analysis, India
Energy and exergy analyses of solar ponds in the Indian climatic conditions
Energy and exergy analyses of a salinity–gradient solar pond (SGSP) (100 × 100 m²) are carried out in the Indian climatic conditions. It has been found that the highest amount of useful low–grade thermal energy, i.e., 24,260 and 28,119 MJ, can be extracted at 80 and 85°C temperature from heat storage zone (HSZ) of the solar ponds at New Delhi and Bhavnagar in the month of May, respectively. Highest and lowest overall energy and exergy efficiency of the SGSPs have been estimated as 10.60 and 1.64%, and 2.7 and 0.4%, respectively. Exergy destructions are estimated to be 6–11.4 MJ/m² in the Upper Convective Zones (UCZs), 2.5-4.8 MJ/m² in the Non–Convective Zones (NCZs) and 3.1–6.2 MJ/m² in the HSZs. The annual overall energy and exergy efficiency of the solar ponds are about 6.46 and 0.9% in New Delhi and 7.09 and 1.07% in Bhavnagar, respectively.