Water source heat pump unit dedicated for tail end of capillary tube net with heat recovery

The utility model discloses a water source heat pump unit dedicated for a tail end of a capillary tube net with heat recovery. The water source heat pump unit comprises a compressor, a heat recoverer, a shell-and-tube condenser, a shell-and-tube evaporator, a dry cartridge filter, an electronic expansion valve, an unpowered oil-return device and a liquid spraying device; an outlet of the compressor is connected with an inlet of the heat recoverer; an inlet of the shell-and-tube condenser is communicated with an outlet of the heat recoverer; an inlet of the dry cartridge filter is communicated with an outlet of the shell-and-tube condenser; an outlet of the dry cartridge filter is connected with an inlet of the electronic expansion valve; an inlet of the shell-and-tube evaporator is communicated with an outlet of the electronic expansion valve; an outlet of the shell-and-tube evaporator is connected with an inlet of the compressor; the liquid spraying device comprises a ball valve and an electromagnetic valve,