Integrated indoor unit heat pump air conditioning system and control method thereof

The invention discloses a multifunctional integrated indoor unit heat pump air conditioning system and a control method thereof. The integrated indoor unit heat pump air conditioning system comprisesan indoor unit and an outdoor unit, wherein the indoor unit adopts an integrated unit and comprises a shell, a water storage tank located in the shell and an indoor heat exchanger; a water inlet pipeline and a water outlet pipeline of the indoor heat exchanger are connected with a heat exchange coil in the water storage tank and an indoor tail end device respectively; a three-way valve communicating with a water supply pipeline of the indoor tail end device is arranged on the water outlet pipeline of the indoor heat exchanger; and a domestic hot water outlet and a water supplementing opening are formed in the water storage tank. The same machine is used for meeting various requirements of users for refrigeration, heating and hot water supply, the purchase cost and the mounting space are saved, and the water temper