Reclaimed water source heat pump system: Reclaimed water (including various domestic and industrial sewage, medium water, etc.) is a more ideal source of low-grade energy, among which the city's primary industrial sewage and domestic sewage are the most easily available. The beneficial properties of reclaimed water include its wide distribution, richness, and ease of getting. The utilizaiton of reclaimed water will not induce any adverse effects to hydrogeology. Moreover, the temperature of reclaimed water is relatively stable among four seasons, which provides relatively higher temperature in winter and relatively lower temperature in summer. The unique features of reclaimed water  make the reclaimed water source heat pump system much more efficient than the traditional air conditioning system, especially in terms of energy and financial costs saving.