Sewage source heat pump system using sewage (domestic wastewater, industrial warm water, industrial equipment, cooling water, waste water production process emissions), with the refrigeration cycle system, through the consumption of a small amount of electricity in the winter water resources in the low-quality energy "to learn " Out, through the network to provide indoor air conditioning, heating systems, domestic hot water system; summer, the indoor heat away and released into the water, in order to achieve the effect of summer air conditioning. Four Wheel Electric Vehicle,Mini Four Wheel Car,4 Wheel Electric Car,4 Wheel Electric Vehicle Xuzhou Hengshang Mechanical and Electrical Co., Ltd. , https://www.hengshangtricycle.com