A heat pump system having a dual heat exchanger structure, the heat pump system comprising:
- a heat source side heat exchange member exchanging heat with a heat source while heat exchange water flows;
- a heat pump exchanging heat with the heat exchange water, which exchanged heat with the heat source through the heat source side heat exchange member, and operating in a cooling operation mode or a heating operation mode;
- an external expansion valve disposed outside of the heat pump to allow a refrigerant passed through the heat pump to expand while passing therethrough;
- a refrigerant-water heat exchanger through which the refrigerant passed through the external expansion valve exchanges heat;
- a heat storage tank storing water to exchange heat with the refrigerant while the water passes through the refrigerant-water heat exchanger;
- and
- a target side end unit capable of providing cooling and heating to a target site depending on the operation mode of the heat pump,
- wherein the refrigerant is able to flow between the heat pump, the refrigerant-water heat exchanger, and the target side end unit,
- wherein, in a non-air-conditioning state for the target site, while the refrigerant is circulating between the heat pump and the refrigerant-water heat exchanger, the water is cooled or heated, and the cooled or heated water is stored in the heat storage tank,
- wherein the heat pump and the heat storage tank are able to supply cooling and heating to the target site in an air-conditioning state for the target site,
- wherein, when the heat pump is in the cooling operation mode and in a non-air-conditioning state for the target site, a cold storage operation is performed such that the refrigerant, which has lost heat through heat exchange with the heat exchange water in the heat pump, flows through the refrigerant-water heat exchanger in an expanded state while passing through the external expansion valve, the refrigerant flowing through the refrigerant-water heat exchanger flows again into the heat pump in a state of absorbing heat of the water flowing through the refrigerant-water heat exchanger, the heat exchange water absorbing the heat of the refrigerant in the heat pump flows again into the heat pump in a state of losing heat through heat exchange with the heat source in the heat source side heat exchange member, and the water is cooled through losing of heat to the refrigerant in the refrigerant-water heat exchanger and the cooled water is stored in the heat storage tank, and
- wherein, when the heat pump is in the cooling operation mode and in an air-conditioning state for the target site, a cold air supply operation is performed such that the refrigerant losing heat and primarily-condensed through heat exchange with the heat exchange water in the heat pump exchanges is secondarily condensed through heat exchange with the cooled water supplied from the heat storage tank while passing through the refrigerant-water heat exchanger, and the secondarily condensed refrigerant supplies cooling to the target site through the target side end unit.