Experimentation of a high temperature thermal energy storage prototype using phase change materials for the thermal protection of a pressurized air solar receiver

The work addresses the issue of fast variations of temperature of a central solar receiver under cloud covering. A specific attention is paid to the situation of Hybrid Solar Gas Turbine (HSGT) systems using pressurized air as Heat Transfer Fluid (HTF), as it is considered in the Pegase project (France). A Thermal Energy Storage (TES) unit integrated in the receiver is proposed for smoothing the variation of temperature. The technology is based on the utilization of both Phase Change Material (PCM) and metallic fins in order to enhance charge and discharge capability of the storage unit. A test-bench is designed with copper fins and is experienced with paraffin wax and with Li2CO3 successively as PCMs. In the same time, the test unit is modeled and the charging and discharging modes are simulated. The results show that the full charging is achieved in about 4 hours starting from 700 degrees C when the receiver is maintained at 900 degrees C, whereas the discharge from 900 degrees C to 700 degrees C is achieved in 2.5 hours. (C) 2013 The Authors. Published by Elsevier Ltd.