Special water source heat pump unit at tail end of capillary tube network

The utility model discloses a special water source heat pump unit at the tail end of a capillary tube network. The water source heat pump unit comprises a compressor, a shell and tube condenser, a shell and tube evaporator, a drying and filtering cylinder, an electronic expansion valve, an unpowered oil return device and a liquid spray device, wherein the outlet of the compressor is communicated with the inlet of the shell and tube condenser; the outlet of the shell and tube condenser is communicated with the inlet of the shell and tube evaporator through the drying and filtering cylinder and the electronic expansion valve; the outlet of the shell and tube evaporator is communicated with the inlet of the compressor; the inlet of the liquid spray device is communicated with a pipeline between the outlet of the drying and filtering cylinder and the inlet of the electronic expansion valve, and is communicated with a liquid spray nozzle on the compressor through a spherical valve and an electromagnetic valve. The