Concentrated solar thermalProject Solar-Driven Supercritical CO2 Brayton Cycle
The CSIRO managed a project that focused on key components of the Supercritical Carbon dioxide power cycle, and addressed components required to implement the cycle with solar energy.
Supercritical Carbon dioxide power cycles enable a significant increase in thermal efficiency over traditional steam Rankine cycles seen in the majority of current thermal power stations both fossil fuelled and solar thermal. The increase in efficiency is achieved by operating the turbine at higher temperatures (close to 700°C), while low compression ratios reduce the amount of worked required to pump the working fluid to the pressures required for the cycle to operate.
Applying the supercritical CO2 power cycle to a concentrating solar thermal system and taking into account the increased conversion efficiency, the solar collector system can be reduced in size for comparable electrical outputs. This translates to lower capital costs for the systems and overall a lower cost of production for the electricity.
This project looked at key components of the Supercritical Carbon dioxide power cycle, and addressed components required to implement the cycle with solar energy. The project demonstrated for the first time a directly illuminated solar receiver with high pressure supercritical carbon dioxide (sCO2), developed and tested the required balance of plant, demonstrated a new sCO2 pump, high pressure recuperators and with scope for future work testing sCO2 turbines.
The project also demonstrated the use of a thermal storage system that allowed the sCO2 flow loop to be commissioned in a controlled environment. This storage can be charged with either solar or combustion heat sources.