Unsteady Numerical Simulation For Studying The Thermocline Phenomenon Inside AStorage Tank For Molten Salt

摘要

Thermal energy storage is considered an important component for the solar power plants. Unsteady–one dimension numerical model of single storage tank for molten salt is developed for studying the thermocline phenomenon inside the tank and the effects of the operating variables on this phenomenon. The model simulates the thermal performance of the storage tank including the heat transfer, temperature profile and the thermal losses. The thickness of the thermocline region was studied with time during charging and discharging processes of the storage tank. From the computation results, the effects of operating parameters, such as flow rate and inlet molten salt temperature, on the thermocline region thickness were investigated. The thickness of thermocline zone and its positions inside the tank were studied versus time. The study found that thickness of the thermocline zone affected by the charging flow rate and progressing time, where the ratio of the thermocline thickness to the total tank height increase from 21.5 to 34.5 % with increasing the flow rate from 0.5 to 2 kg/s, respectively. While during discharging process, the thermocline thickness was increased from 0.34 to 1.1 m with progressing time from 1 to 9 hr, respectively. The modeling based on unsteady and one dimension energy balance equations that were solved using EES software.