Thermodynamic analysis and optimization of a combined cooling and power system using ocean thermal energy and solar energy

Abstract

Ocean thermal energy and solar energy have great potential for development in energy conversion systems. In this study, a new type of combined cooling and power (CCP) system using solar energy and ocean thermal energy is proposed. The effects of evaporating temperature and condensing temperature of the organic Rankine cycle, evaporating temperature of refrigeration cycle, split ratio, mass flow, the proportion of solar energy to total heat absorption on the performance of CCP system are investigated. The results indicate that the increase of evaporating temperature resulting in a rise in Primary Energy Efficiency Ratio (PER) and exergy efficiency, while the increase of condensing temperature leads to the decrease of PER and exergy efficiency. R1234ze(E), R1234yf, R134a, R245fa, and R32 are screened under the optimal operating conditions, and R32 is the most suitable working fluid with the highest PER of 9.99% and the exergy efficiency of 11.94%. The exergy loss is concentrated in the heat transfer process, among which the exergy loss of the condenser is the highest of 168.29 kW, accounting for 46.68% of the total exergy loss. The increase in the proportion of solar energy absorption to the total heat absorption will reduce the PER and exergy efficiency.