Exergetic performance analysis of a salinity gradient solar pond

Solar pond technology is an effective and most economical way for converting and storing the solar heat energy. In this paper, numerical and experimental studies have been conducted for investigating the energy/exergy distributions and also efficiencies in the inner zones of a circular solar pond. For this purpose, a small scale solar pond with a circular cross-section was built and tested in Urmia University in Urmia-Iran. The height and area of the solar pond were equal to 1.1 m and 4 m2, respectively. In the small solar ponds, the shading walls affects the accumulation of solar energy and thermal energy storage. Therefore, for achieving a complete understanding of the energy performance in the small solar ponds, a shading model is also developed for circular solar ponds. Therefore, by using the proper relations and considering the shading effect, energy and exergy efficiencies were analyzed in the inner zones of the pond. For lower convective zone, the highest energy and exergy efficiencies were obtained in the month of June and were equal to 9.37% and 0.76%, respectively. The results confirmed that most of the thermal energy is stored in the lower convective zone and it can be used in various applications.