Solar Energy, Vol.207, 144-156, 2020
Supercritical carbon dioxide cycles with multi-heating in Concentrating Solar Power plants
This work analyses the features and performance of supercritical CO2 cycles with multi-heating (heat supplies at different temperature) in Concentrating Solar Power plants, including its internal coherent integration. The specific features of multi-heating cycles fit perfectly with the characteristics of concentrating solar energy. The integration requires the design of a new type of solar field to accommodate the solar radiation hitting the receiver to the multi-heating requirements. This new solar field has a similar configuration to the solar tower, but receiver and heliostats are divided into two sections, and each section meets different requirements in concentration ratio, fluid temperature, and absorbed heat flux. This new solar field, called multi-heating solar tower, achieves higher efficiencies than standard solar towers with softer thermal requirements. The flexibility of the multi-heating structure is very useful to solve efficiently the restrictions of supercritical CO2 cycles caused by the variations of specific heat close to the critical point. The resulting CSP plant with multi-heating achieves higher efficiency than plants with standard solar towers and supercritical CO2 cycle.