Investigation on the regulating methods of air source heat pump system used for district heating: Considering the energy loss caused by frosting and on–off.

• Three adjusting methods suitable for district heating using ASHPs are proposed. • Energy loss corrections of frosting and on–off are adopted in the simulation model. • Power consumption increment caused by the correction of frosting reaches 3.85–17.41%. • Energy loss ratio of on–off declines from 3.19% to 0.68% with heating area increase. • Energy-saving potential of pump reaches 80.97–86.46% in different adjusting methods. Air source heat pump (ASHP) has been used in Northern China for district heating. However, few investigations on its regulating methods have been conducted till now. To increase the energy-saving effect of AHSPs, a simulation model, which considered the energy loss caused by frosting and on–off, was developed in this paper. Based on this model, three combination regulating modes suitable for district heating using ASHPs as heating source were proposed. Then the heating performance of ASHPs used for district heating in seven cities was investigated using this model. Results showed that both the energy loss corrections of frosting and on–off have evident impacts on the power consumption and seasonal coefficient of performance (SCOP). Owing to the energy loss correction of frosting, the power consumption of ASHP unit is increased by 3.85%–17.41%, and meanwhile SCOP is decreased by 3.72%–14.83%. The influence of the energy loss of on–off decreases gradually with the increase of heating area. In the three regulating modes, the power consumption of ASHP unit changes slightly, while the energy saving rate of water pump can reach 80.97%–86.46%. When the pitch of buried pipe was 300 mm, ASHP can meet the heating demand in all the three regulating modes. [ABSTRACT FROM AUTHOR]