Injector

Engineering

Exergy efficiency

Evaporator

Cooling capacity

Working fluid

Heat exchanger

Transcritical cycle

Mechanical engineering

Thermodynamics

Physics

Nuclear engineering

Process engineering

Environmental science

Turbine

Chemistry

Separator (oil production)

Refrigeration

Water cooling

Refrigerant

Exergy

Energy Conversion and Management

Transcritical CO2 power cycle is an available technology for low grade heat source recovery, but the low critical temperature (about 31℃) of CO2 working fluid restricts its practical application because it is hard to ensure the condensation for CO2 working fluid under the environmental temperature. In this paper, two novel combined cooling and power (CCP) systems with separators are proposed, namely the HCO2R (High concentration CO2 mixture Refrigeration) CCP system and LCO2R (Low concentration CO2 mixture Refrigeration) CCP system, which integrate a transcritical CO2 power cycle with an ejector refrigeration cycle. For ensuring the working fluid condensation under environmental temperature, CO2-based mixtures (i.e. the mixture of CO2/R32) are using as the working fluid in the proposed systems. Because of the composition separation characteristic of the CO2-based mixtures, a separator is introduced into the novel system and placed at the ejector outlet. And the two parts of CO2-based mixture working fluid from separator with different mass concentrations respectively enter the turbine and evaporator for generating power and refrigeration capacity. The system mathematical model is established, the parametric studies and comparison between novel systems and conventional ejector-CCP system are implemented. The results reveal that the novel systems have better thermal performance. The HCO2R-CCP system presents higher thermal efficiency and the LCO2R-CCP system presents higher net power output. In most cases, the LCO2R-CCP system presents higher the exergy efficiency compared to the conventional ejector-CCP system.

Thermodynamic analysis and comparison study of two novel combined cooling and power systems with separators using CO2-based mixture for low grade heat source recovery