Keywords: combined cycle, CO2, energy analysis, exergy analysis, carbon dioxide, ejector expansion, refrigeration cycle, heat exchangers, size, thermodynamic analysis, Brayton power cycle, energy saving, second law efficiency
Energy and exergy analyses of a new combined cycle using carbon dioxide as working fluid
In this study, a new combined cycle based on the Brayton power cycle and the ejector expansion refrigeration cycle is proposed. The proposed cycle can provide simultaneous heating, cooling and power. And be driven by low temperature heat sources. The suggested cycle can save energy around 46% in comparison with a system producing cooling, power and hot water separately. Moreover, the second law efficiency of the combined system is around 30% which can be obtained under the given conditions. Finally, the surface area of the heat exchangers is determined. The suggested cycle can be a promising combined system for buildings and outland regions.