Effects of parameters on performance of high temperature molten salt latent heat storage unit

Abstract

In order to investigate the performance of high temperature molten salt latent heat storage (LHS) unit under variable conditions, the effects of heat transfer fluid (HTF) inlet temperature, velocity and tube geometric parameters on melting time, melting fraction, heat storage rate and solid–liquid interface were numerically investigated. The results show that within the studied parameters, the HTF inlet temperature has the largest effect on LHS rate. With the HTF inlet temperature increasing from 1070 K to 1110 K, the melting time reduces 53.0%. However, the larger inlet temperature will result in more non-uniform melting rate and solid–liquid interface distribution. The second important influential factor is the HTF inlet velocity. When inlet velocity increases from 10 m/s to 20 m/s, the melting time reduces 45.4%. And the effect of velocity on the solid–liquid interface distribution is uniform. LHS tube diameter has the lowest effect on performance. With outer tube radius increasing from 24.0 mm to 28.0 mm, the melting time only augments 16.3% and the solid–liquid interface distribution becomes more uniform. In a general conclusion, when the heat load of the heat source is larger, a larger HTF mass flow rate is suitable to maintain a moderate HTF temperature. And then for the LHS unit, a larger tube diameter is recommendable.