Performance improvement of dry cooled advanced concentrating solar power plants using daytime radiative cooling

Abstract

In this study, utilization of daytime radiative cooling to enhance the performance of air-cooled concentrating solar thermal power plants is investigated. Water scarcity and environmental concerns are the driving forces for solar thermal power plants to use dry cooling systems. In order to overcome the energy conversion efficiency penalties associated with using air cooled technologies various supplemental cooling techniques have been proposed. Recent advancements in manufacturing structures with selective radiative properties have made the daytime radiative cooling to the cold outer space practical. In this work, the efficiency improvement of the air-cooled advanced supercritical carbon dioxide power cycles coupled with a radiative cooler is explored.It is shown that for the simple supercritical carbon dioxide cycle operating at hot source temperature equal 550°C by employing 14.02m2/kWe radiative cooler, it is possible to overcome the efficiency losses due to air cooling and the net output of the cycle improves by 5.0%. At hot source temperature equal 800°C, the required radiative cooler area is 4.38m2/kWe and respective performance improvement is equal 3.1%. For the recompression supercritical carbon dioxide cycle operating at hot source temperature equal 550°C by employing 18.26m2/kWe radiative cooler, it is possible to overcome the efficiency losses due to air cooling and the net output of the cycle improves by 7.5%. At hot source temperature equal 800°C, the required radiative cooler area is 10.46m2/kWe and respective performance improvement is equal 4.9%.