Thermal storage for solar steam power plants

Solar thermal power plants are able to continue operating through periods of cloud cover and into the night, provided that extra solar heat is stored during sunny periods and can be extracted when needed. For power plants based on the steam Rankine cycle, most of the heat is needed at a constant temperature of around 300°C, which ideally matches the storage temperature of the Phase Change Materials (PCM). Unfortunately due to their low thermal conductivity, suitable PCMs do not allow easy input and extraction of the heat, and this barrier prevents efficient charging and discharging of the storage material. We are developing an innovative method of heat transfer that will overcome this bottleneck, enabling fast transfer of heat into and out of the storage material while at the same time minimising temperature changes and keeping the process at nearly constant temperature (isothermal). This will allow the power plant to maintain constant high efficiencies when operating from storage. We are analysing the proposed process in order to validate its principles, and we’re constructing a detailed simulation for predicting its performance. Following this validation, an experimental model will be built to demonstrate and measure actual performance.

Collaboration: M. Rosenfeld (TAU)