COOLING AND HEATING SWITCHING DEVICE FOR VARIABLE REFRIGERANT FLOW SYSTEM CAPABLE OF HEAT RECOVERY, VARIABLE REFRIGERANT FLOW SYSTEM, AND CONTROL METHOD

摘要

A cooling and heating switching device for a variable refrigerant flow system capable of heat recovery, a variable refrigerant flow system, and a control method. Ends of multiple high-pressure branch pipes of the cooling and heating switching device are respectively connected to ends of multiple low-pressure branch pipes, so as to form multiple connection nodes. The multiple connection nodes are respectively connected to gas pipes of multiple indoor units. Further ends of the multiple high-pressure branch pipes are connected to a high-pressure gas pipe (3). Further ends of the multiple low-pressure branch pipes are connected to a low-pressure gas pipe (2). Ends of multiple branch liquid pipes are respectively connected to ends of multiple liquid sub-pipes, so as to form multiple connection nodes. The multiple connection nodes are respectively connected to liquid pipes of the multiple indoor units. Further ends of the multiple branch liquid pipes are connected to a main liquid pipe (1). Further ends of the multiple liquid sub-pipes are connected to a main pipe inlet of a subcooler (4). A throttling structure is provided on a connection pipe between a cooling branch pipe inlet (C) and a main pipe outlet (B). The cooling branch pipe outlet (B) is connected to the low-pressure gas pipe (2), thereby solving the issue of loud noise caused by a flowing refrigerant in an indoor unit of a variable refrigerant flow capable of heat recovery, and achieving a compact structure and low costs.