Full-range performance analysis of CO2 water-source heat pump and determination of optimal degree of superheat

Based on the experimental study on transcritical CO2 water-source heat pump and neural network fitting model, systematically analyses the performance characteristics of the heat pump under full-range operating conditions as well as different control strategies, and summarizes the sensitivity of the system COP, heating capacity and degree of superheat to the heat source temperature, the water supply/return temperature and the open degree of electronic expansion valve. The results show that the heat source temperature has the largest influence on the system performance, and the maximum change of COP, heating capacity and degree of superheat with respect to unit heat source temperature exceeds 0.2, 4 kW and 1℃ respectively. The optimal degree of superheat is fitted as a linear function of the heat source temperature and water supply/return temperature. Gives the fitting formula, providing the reference for setting of the optimal degree of superheat for PID control of the heat pump system.