Investigation of temperature development in salinity gradient solar pond using a transient model of heat transfer

•The numerical model is validated with experimental results.•The influence of thickness of zones on LCZ temperature is investigated.•The warm-up time required to achieve maximum temperature of LCZ is discussed.•A detailed assessment of surface losses is depicted and discussed.•The impact of ground condition and NCZ thickness on LCZ temperature is presented. Solar pond utilizes a salinity gradient to trap thermal energy in the storage zone. The stored heat can be employed for several potential applications. A transient analysis is carried out to investigate the effect of various parameters such as variation of the thickness of zones, ground conditions, and surface losses on the temperature development of solar pond. The numerical model is validated with experimental results from two different locations obtained from the literature. The thickness of each zone is determined based on the maximum temperature of LCZ and fast warm-up time under the meteorological conditions of Bhavnagar. The thickness of UCZ, NCZ, and LCZ are selected as 0.3 m, 1.3 m, and 1.5 m, respectively, for the subsequent study of the solar pond. It is found that a phase difference of nearly 42 days occurs between maximum values of solar radiation and temperature of LCZ for a given set of conditions. The dependence of LCZ temperature on the thickness of NCZ and ground conditions is also presented. A detailed assessment of surface losses shows the evaporation loss to be higher than convection and radiation losses. The impact of evaporation loss is highest in the temperature of UCZ and LCZ; however, the change in the LCZ temperature due to surface losses is minimal. Also, the shading area should be considered for the investigation of smaller area of pond. Solar pond with larger area requires less duration to acquire high temperature.