Parametric analysis of a new combined cooling, heating and power system with transcritical CO2 driven by solar energy

In order to utilize renewable energy to meet diverse energy requirements, a new combined cooling, heating and power (CCHP) system is proposed to produce cooling output, heating output and power output simultaneously. This proposed system combines a Brayton cycle and a transcritical CO2 refrigeration cycle with ejector-expansion device, which uses solar energy as the heat source to reduce fossil fuel consumption and alleviate environmental problems. A mathematical model is developed to simulate the new CCHP system with transcritical CO2 driven by solar energy under steady-state conditions, and the thermal efficiency and exergy efficiency are used to evaluate the system performance. The effects of several key thermodynamic parameters on the system performance are examined. The results indicate that increasing turbine inlet pressure and ejector inlet temperature could lower the efficiency of the system, and increasing turbine back pressure and turbine inlet temperature could elevate the efficiency of system. In addition, as ejector back pressure increases, the thermal efficiency of system decreases, but the exergy efficiency increases.

► The new CCHP system combines a Brayton cycle and a transcritical CO2 refrigeration cycle.
► CO2 is used as the working fluid, which is a natural substance and beneficial to environment.
► The effects of key thermodynamic parameters on the system performance are examined.