Liquid metals have received growing attention as a potential replacement for more conventional heat transfer fluids in concentrated solar power (CSP) systems. Owing to liquid metals high thermal conductivity, an increase in solar receiver efficiency as well as higher serviceable temperatures could enable more advanced power cycles to be integrated to the CSP system. Recently, CSIRO carried out research on a solar air turbine system which includes a demonstration of a high-temperature pressurized air receiver combined with high-temperature thermal storage. Since the operation temperature of a solar air turbine system is much higher than that of conventional CSP systems, Lead-Bismuth Eutectic (LBE) alloy was chosen for its favorable high temperature heat transport properties and relative ease of storage. The heat test apparatus consisted of a LBE-air heat exchanger, storage tanks with internal heating elements and a pumping system developed by CSIRO. During the test, approximately 1,000 kg of LBE was successfully pumped while capturing and storing approximately 35MJ of solar energy. The test successfully transferred heat from the solar air receiver to the LBE, with the temperature of stored LBE reaching over 770 °C.
This paper will present the concept of the test system, design of its components, procedures and results of the test, and also lessons learnt.