Comparative research of heat discharging characteristic of single tank molten salt thermal energy storage system

Abstract

The single tank molten salt thermal energy storage (TES) system has been extensively studied due to its low cost and high efficiency performance. The binary nitrates (KNO3+Ca(NO3)2) is selected as heat storage medium in this study, which the melting point is 116.9 °C. This research aims to achieve stable and constant heat discharging performance of the single tank molten salt TES system. Three different inlet velocity conditions such as constant value, manual and automatic adjustment are comparatively studied. The results show that the heat discharging power drops with the heat discharging time increases under constant inlet velocity. The heat discharging time decreases with the increasing of inlet velocity while the heat discharging power increases with the increasing of the inlet velocity. The correlations between the inlet velocity and heat discharging time, the average temperature of molten salt in the single tank are proposed. The heat discharging power of manual and automatic adjustment of inlet velocity is in ±10% and ±3% fluctuation of the set value. The results could provide practical and effective guide to design the single tank molten salt TES system.