Simulation and performance optimization of a novel hybrid CCHP system based on the prime movers of internal combustion engine and Stirling engine

Combined cooling, heating, and power systems (CCHP) could increase the efficiency of conventional energy supply systems and mitigate carbon emissions. In this paper, a novel arrangement of a combined cooling, heating, and power (CCHP) system is presented with prime movers of internal combustion and Stirling engines, which are numerically simulated by Range-Kutta method and optimized with the genetic algorithm technique. The influence of some key parameters such as Stirling engine speed, phase angle, length and porosity of Stirling engine's regenerator, and also speed and spark timing of the internal combustion engine, on the capacity, efficiency, primary energy saving and the investment payback period of the CCHP system has been discussed. The results illustrated that using the CCHP system with hybrid prime movers, due to the appropriate efficiency of the combustion engine, allows the Stirling engine to be started at high speeds. In this condition, the overall efficiency of the hybrid system is increased by 12 % compared to using the CCHP system with only the Stirling engine. Additionally, the payback period of the CCHP system with combined prime movers at 3500 rpm for the two engines is approximately 4.4 years, which is about 1.6 years shorter than the payback period of the CCHP system based solely on the internal combustion engine. This work provides valuable insights into the design and optimization of hybrid CCHP systems with two different combustion-based prime movers.