Air conditioner

1. An air conditioning system comprising:

a refrigerant circulating path network connecting, with refrigerant lines, a compressor; a heat-source side heat exchanger for evaporating and gasifying or condensing and liquefying a heat-source side refrigerant; expansion valves for controlling a flow rate of the refrigerant; refrigerant pipes in intermediate heat exchangers for exchanging heat between the heat-source side refrigerant and a use-side heat medium; and a four-way valve, a plurality of two-way valves or a plurality of three-way valves for switching a circulation path of the refrigerant, for circulating the heat-source side refrigerant; and

a heat medium circulating path network connecting, with heat-medium lines, pumps for pressurizing and sending the heat medium; use-side heat exchangers for exchanging heat between the heat medium with air in interior spaces to be air conditioned; and heat-medium pipes in the intermediate heat exchangers, for circulating the heat medium,

wherein

temperatures in the interior spaces to be air conditioned are controlled by exchanging heat, through the use-side heat exchangers, between the air in the interior spaces to be air-conditioned and the heat medium heated or cooled by the heat-source side refrigerant in the intermediate heat exchangers,

the air conditioning system further comprising:

integrated heat-medium flow-path switching devices connectedly interposed between the intermediate heat exchangers and the use-side heat exchangers, each integrated heat-medium flow-path switching device including thereinside:

a heat-medium flow-path switching valve having holes formed in its sidewall and having a longitudinal inner partition, a first end and a second end opposite the first end, the longitudinal inner partition extending from the first end to the second end,

wherein the heat-medium flow-path switching valve is revolved to select either of the heated heat medium or the cooled heat medium for it to flow between the intermediate heat exchangers and the use-side heat exchangers, whereby air conditioning is performed.

2. The air conditioning system of claim 1 , wherein in a case of providing the plurality of use-side heat exchangers, the same or less number of integrated heat-medium flow-path switching devices as or than the number of use-side heat exchangers are provided to perform a heating only operation mode in which all intermediate heat exchangers act as condensers, a cooling only operation mode in which all intermediate heat exchangers act as evaporators, and a cooling and heating mixed operation mode in which part of the intermediate heat exchangers act as a condenser and the other part of the intermediate heat exchangers act as an evaporator.

3. The air conditioning system of claim 2 , wherein flow rates of the heat medium flowing between the intermediate heat exchangers and the use-side heat exchangers are controlled during each operation mode.

4. The air conditioning system of claim 3 , wherein switching between the heated heat medium and cooled the heat medium as well as adjusting the flow rates of the heat medium are performed by single drive units provided in the integrated heat-medium flow-path switching devices so as to keep at target values the differences between temperatures measured with temperature sensors provided to the intermediate heat exchangers and temperatures of the heat medium at the use-side heat exchangers.

5. The air conditioning system of claim 3 , wherein in each operation mode, heat-medium flow paths between the intermediate heat exchangers and the use-side heat exchangers are closed by controlling part of or all of the drive units in the plurality of integrated heat-medium flow-path switching devices to close the flow paths.

6. The air conditioning system of claim 1 , wherein the refrigerant with which the refrigerant circulating path network is charged is a single refrigerant, a near-azeotropic refrigerant mixture, a non-azeotropic refrigerant mixture, or a natural refrigerant that is changeable to a two-phase state or a supercritical state.

7. The air conditioning system of claim 1 , wherein the heat medium with which the heat-medium circulating path network is filled is an antifreeze liquid or a mixture of water and an additive having a high anti-corrosion effect.

8. The air conditioning system of claim 1 , wherein the flow paths of the heat medium are formed by configuring integrated heat-medium flow-path switching devices such that part of flow paths of at least one of the heated heat medium and the cooled heat medium are connectedly formed in the integrated heat-medium flow-path switching devices.

9. The air conditioning system of claim 1 , wherein the flow paths of the heat medium are formed by joining pipes that are connected to the integrated heat-medium flow-path switching device(s) and through which at least one of the heated heat medium and the cooled heat medium is passed, to allow the number of integrated heat-medium flow-path switching devices to be changeable.