Exergoeconomic and Exergoenvironmental Analysis of a Novel Power and Cooling Cogeneration System Based on Organic Rankine Cycle and Ejector Refrigeration Cycle

Abstract

A novel combined power and refrigeration system is proposed based on organic Rankine and jet refrigeration cycles. The system has a wider application range and can be adjusted to different cooling and evaporation temperatures. To meet the needs of diverse populations, the cooling and evaporation temperature can be as low as −60 degrees Celsius. The genetic algorithm is used to optimize the system, and the proposed system’s energy, exergy, economy, and environment are analyzed under optimal conditions. The results desmonstrate that the exergy damage, environmental impact rate, and exergy economic coefficient of steam turbine are the largest. The system’s exergy damage and the turbine’s investment cost are reduced, and the system’s performance is improved. The condenser has the greatest potential for improvement and should be considered a priority component for system improvement. In addition, the system parameters are analyzed. Higher low-pressure steam generation temperature, dryness of low-pressure steam generator outlet, turbine steam extraction ratio, refrigeration evaporation temperature, and compressor compression ratio are advantageous to system cooling capacity output but not the system net power.High-pressure evaporation temperature is unfavorable to the system’s output of net power and cooling capacity. Still, it is beneficial to improve the thermal and energy efficiency of the system. Under the same operating conditions, compared with the system proposed by predecessors, the system’s net power is increased by 12.52 kW, the thermal efficiency is increased by 4.27%, and the energy efficiency is increased by 2.57%. The system was optimized by taking low-pressure evaporation temperature, high-pressure evaporation temperature, outlet dryness of low-pressure steam generator, suction ratio of steam turbine and compression ratio of compressor as decision variables, and thermal efficiency, exergy efficiency, SUCP and SUEP as objective functions. The low-pressure evaporation temperature, high-pressure evaporation temperature, outlet dryness of low-pressure steam generator, suction ratio of steam turbine, and compression ratio of compressor are 357.99 K, 385.72 K, 0.1, and 0, respectively. The system thermal efficiency is 15.01%, exergy efficiency is 43.18%, SUCP is 45.525USD/MWh, and SUEP is 5122.6 MPTS/MWh.