Water circulation system associated with refrigerant cycle

A system for circulating water and refrigerant, the system comprising:

• a first refrigerant circulation device in which a first refrigerant that exchanges heat with outdoor air flows through a first tube to perform a refrigerant cycle, the first refrigerant circulation device including a first compressor, an outdoor heat exchanger, and a first expander;
• a second refrigerant circulation device in which a second refrigerant that exchanges heat with the first refrigerant flows through a second tube to perform the refrigerant cycle, the second refrigerant circulation device including a second compressor and a second expander;
• a water circulation device in which water flows through a water tube to at least one of perform indoor air conditioning or supply hot water;
• an intermediate heat exchanger which comprises the first tube, the second tube, and the water tube, the intermediate heat exchanger including a plurality of flow passages through which the first refrigerant of the first refrigerant circulation device, the second refrigerant of the second refrigerant circulation device, and the water of the water circulation device independently flow, the plurality of flow passages having a common axis and different diameters in order to exchange heat among the first refrigerant, the second refrigerant, and the water;
• a water-refrigerant heat exchanger provided at one side of the intermediate heat exchanger, wherein the water-refrigerant heat exchanger includes a refrigerant flow passage into which the second refrigerant flows and a water flow passage into which the water that exchanges heat with the second refrigerant flows;
• a plurality of inlets and outlets provided in the first tube, the second tube, and the water tube;
• and
• a plurality of valves installed at the plurality of inlets and outlets to selectively block the plurality of inlets and outlets, wherein the first compressor operates such that the first refrigerant discharged from the first compressor sequentially flows through the outdoor heat exchanger, the first expander, and one of the plurality of flow passages of the intermediate heat exchanger, and wherein the second compressor operates such that the second refrigerant discharged from the second compressor sequentially flows through another one of the plurality of flow passages of the intermediate heat exchanger, the second expander, and the refrigerant flow passage of the water-refrigerant heat exchanger.