Matching Characteristics of Two Heat Exchangers for the Direct Sewage Source Heat Pump System

According to the switching mode of the cooling and heating function, the urban sewage source heat pump unit can be divided into water-side (external) switching unit and machine-side (internal) switching unit. For the design of sewage source heat pump unit, this paper first discusses the standard working conditions of sewage source heat pump unit, analyses the relationship between the performance of external and internal switching units and the matching of two heat exchangers and compares the characteristics and selection methods of internal and external switching units.