This paper proposes a new solar sewage dual-source heat pump heating system and explores its application in winter heating in nearly zero-energy buildings in Changchun

Urumqi

Xining

Beijing

and Shanghai. This operation affects the economy of producing domestic hot water throughout the year. The average heating temperature of the system in the five cities is above 40 ℃ and the average temperature of domestic hot water is above 33 ℃

excluding electric heating. The operation performance reveals that the system is good

but electric heating is still needed to ensure the reliability of the operation. In winter

the energy efficiency of the system in the five cities is more than 3.5

and the energy-saving effect is remarkable. In addition to Urumqi (owing to the low gas price compared to other cities)

this system is economically advantageous compared to the traditional electric hot water and natural gas hot water systems.