Performance study of a closed loop gas engine heat pump drying system for tobacco drying

The gas engine heat pump is a heat pump system that uses natural gas as energy input and drives the compressor for the heat pump cycle. It has the characteristics of high primary energy utilization and environmental friendliness. In order to solve the problem of high energy consumption in traditional tobacco drying, this paper introduces a closed loop gas engine heat pump drying system (CGEHPDS). This study uses a simulation model based on MATLAB to evaluate the system performance, focusing on the energy efficiency, dehumidification, and operation characteristics of the tobacco drying process. The simulation results show that reducing the supply air temperature and increasing the air volume can improve COP and PER, but will increase energy consumption and power. The results of the tobacco drying cycle indicated that CGEHPDS showed high energy efficiency in the overall process of tobacco leaves, COP value maintained between 2.69 and 4.42 under most working conditions, PER value remained between 1.44 and 1.99 for most of the time, and SMER value was up to 1.85 kg/kWh. The operation law of the heat pump system changed with the change of the tobacco drying process. Through the energy-saving economic analysis of coal, gas unit price, and electric energy consumption, the system has potential advantages in energy saving and cost control. The research provides theoretical reference and data support for the design optimization and engineering application of CGEHPDS.