Multiscale Concentrated Solar Power

This chapter highlights the multiscale concentrated solar power thrust, which focused on developing new low-cost manufacturable technologies for both high- and moderate-temperature thermal cycles. In the high-temperature range, the focus was on the supercritical carbon dioxide (s-CO₂) Brayton cycle. Research involved developing low-cost heliostats coupled with novel bladed receivers and a novel CO₂ test loop. A key focus was developing a functional testbed to evaluate and optimize the Brayton cycle as a cost-shared effort with the Indian Institute of Science. The project also investigated developing a novel helical receiver to heat the CO₂. Extensive computational modeling of the thermal flow and gradients was conducted to develop the novel CO₂ cycle. The program also pursued developing low-cost mirrors, absorbers, and troughs for Rankine cycle solar thermal parabolic trough technology. A new small-scale, positive-displacement organic Rankine cycle expander was developed and tested. Solution-based approaches were considered that promise low-cost manufacturing. Coupled with the heat-collection work were investigations of thermal storage approaches. Specifically, new molten salts were developed capable of much higher-temperature performance with improved thermal conductivity, and a new system was developed for low-temperature Rankine systems.