Performance analysis of air source heat pump space heating system with an adaptive control for supply water temperature

Abstract

• An adaptive control method for supply water temperature is proposed. • Model parameters are identified by the new control method quickly and accurately. • Coefficient of performance of experimental unit increases by 21.16%. • A decrease of 34.24% in building energy consumption is achieved. Air source heat pumps (ASHPs) have been widely used for heating in buildings. While in practice, the setting value of its supply water temperature is always far higher than the theoretical value owing to the delayed regulation, and this results in the low coefficient of performance. To solve this problem, an adaptive control method for the supply water temperature was proposed in present work. This control method could predict the best setting value of supply water temperature based on the heat-balance of the heat exchange amount in indoor fan-coils and building heating load, and the least squares method was used to achieve the adaptive identification of parameters. By adopting this control method in a field ASHP system, four sets of experiments were conducted. Results showed that this control method could quickly and accurately adapt to the actual project, and adjust the water temperature according to heating demand. When employing the new control method, the average supply water temperature was reduced by 8.4 °C, and lower supply water temperature made the coefficient of performance of ASHP unit increased by 21.16%; the building energy consumption was reduced by 34.24%, and the power consumption of the ASHP unit was reduced by 38.20%.