Multi-Objective Energy-Saving Optimization and Analysis of a Combined Cooling, Heating, and Power (CCHP) System Driven by Geothermal Energy and LNG Cold Energy

Abstract

In this paper, a new type of cogeneration system using LNG cold energy as a cooling source and geothermal energy as a heat source is designed and studied from the perspective of LNG cold energy gradient utilization. The system integrates power generation, cold storage, and district cooling. In order to provide more detailed information, the proposed system was analyzed in terms of energy, exergy, and economy. The effects of separator pressure, LNG pump outlet pressure, the mass flow rate of n-Pentane in ORC-I, liquefaction temperature of R23 in the cold storage module, and pump 5 outlet pressure in the refrigeration module on the performance of the system were also investigated. Additionally, the particle swarm algorithm (PSO) was used to optimize the CCHP system with multiple objectives to determine the system’s optimal operation. The optimization results show that the system’s thermal efficiency, exergy efficiency, and depreciation payback period are 66.06%, 42.52%, and 4.509 years, respectively.