Experimental investigation on CO2-based combined cooling and power cycle

Abstract

CO2-based combined cooling and power cycle has received increasing attentions especially in scenarios with diversified energy desires for its outstanding thermophysical properties in the recent years. Nevertheless, the current researches on the CO2-based combined cycle devote most to theoretical explorations rather than experimental studies yet. In this work, an experimental prototype of CO2-based combined cooling and power cycle, which is driven by engine waste heat, is developed with the purpose of filling the gaps in the related experiments. The combined cycle integrates a CO2 power sub-cycle and refrigeration sub-cycle via the conjunct condenser and reservoir, with an 10 kW-scale designed output of both power and refrigeration capacity. The flexibility of the prototype is validated, and impacts of external perturbations in the major components on system operation and performance are comprehensively explored. The results indicate that the perturbations in the refrigeration side impose insignificant impacts on the operating of the power side, while any perturbation in the power side may exert dramatic influences on the performance of the former. Simultaneous 5.11 kW power and 5.40 kW refrigeration outputs are achieved in the combined cycle with 93.1 kW heat input, where it operates at a turbine inlet pressure of 10.45 MPa, condensing temperature of 24.5 °C, and evaporating temperature of −0.6 °C. Detailed comparisons between the designed and tested results are conducted to ascertain the deficiencies in the present work and potential measures are concluded to further improve the performance of the combined cycle.