Outdoor unit of gas heat pump system

An outdoor unit of a gas heat pump system, comprising:

• a base;
• a compressor installed on the base;
• a storage tank provided at a suction-side of the compressor to store a refrigerant to be supplied to the compressor;
• a refrigerant pipe configured to connect the compressor to the storage tank, the refrigerant pipe being configured to guide a flow of the refrigerant;
• an engine which is installed on the base to provide power that drives the compressor and in which a mixed fuel of a fuel and air is burned;
• a cooling water pipe configured to guide a flow of cooling water that cools the engine;
• and
• a heat exchanger in which the refrigerant flowing through the refrigerant pipe is heat-exchanged, or the cooling water flowing through the cooling water pipe is heat-exchanged, wherein the storage tank comprises:
• a case in which a refrigerant storage space is defined;
• a partition wall disposed inside the case to partition the refrigerant storage space into an upper space and a lower space;
• and
• a receiver configured to store liquid refrigerant of the refrigerant defined in the lower space, wherein the heat exchanger comprises first and second heat exchangers, wherein the first and second heat exchangers are coupled to an outer circumferential surface of the storage tank at first and second lateral sides and are provided above the partition wall, wherein an upper end of the second heat exchanger is positioned above a lower end of the first heat exchanger, and wherein a lower end of the second heat exchanger is positioned below the lower end of the first heat exchanger.