Air conditioning apparatus

An air-conditioning apparatus comprising:

• a compressor;
• a heat source side heat exchanger;
• a plurality of expansion devices;
• a plurality of heat exchangers related to heat medium;
• a plurality of pumps;
• and a plurality of use side heat exchangers,
• the compressor, the heat source side heat exchanger, the expansion devices, and the heat exchangers related to heat medium being connected to form a refrigerant circuit in which a heat-source-side refrigerant is circulated,
• the pumps, the use side heat exchangers, and the heat exchangers related to heat medium being connected to form a plurality of heat medium circuits in which a heat medium is circulated,
• the air-conditioning apparatus being configured to carry out:
• a heating only operation mode in which a high-temperature high-pressure heat-source-side refrigerant discharged from the compressor flows into each of the heat exchangers related to heat medium to heat the heat medium;
• a cooling only operation mode in which a low-temperature low-pressure heat-source-side refrigerant flows into each of the heat exchangers related to heat medium to cool the heat medium;
• and
• a cooling and heating mixed operation mode in which a high-temperature high-pressure heat-source-side refrigerant discharged from the compressor flows into one of the heat exchangers related to heat medium to heat the heat medium and a low-temperature low-pressure heat-source-side refrigerant flows into another one of the heat exchangers related to heat medium to cool the heat medium,
• the apparatus comprising:
• a first heat medium flow switching device provided on an outlet side of each of the use side heat exchangers, the first heat medium flow switching device switching flow paths between the outlet side of the use side heat exchanger and the heat exchangers related to heat medium;
• and
• a second heat medium flow switching device provided on an inlet side of each of the use side heat exchangers, the second heat medium flow switching device switching flow paths between the inlet side of the use side heat exchanger and the heat exchangers related to heat medium, wherein
• in the cooling and heating mixed operation mode, the first heat medium flow switching devices and the second heat medium flow switching devices are controlled such that a flow path through which the heat medium circulates is formed between the heat exchanger related to heat medium heating the heat medium and at least one of the use side heat exchangers and a flow path through which the heat medium circulates is formed between the heat exchanger related to heat medium cooling the heat medium and at least one of the use side heat exchangers, and
• in the heating only operation mode and the cooling only operation mode,
• the flow path of the refrigerant in the refrigerant circuit is formed such that the refrigerant discharged from the compressor branches to flow in parallel into the plurality of use side heat exchangers and then the refrigerant flowed out of the plurality of use side heat exchanges merges together,
• the first heat medium flow switching devices are controlled to be open to each of the plurality of the heat exchangers related to heat medium such that the heat medium having flowed out from each of the use side heat exchanges flows into each of the heat exchangers related to heat medium, the second heat medium flow switching devices are controlled to be open to each of the plurality of the heat exchangers related to heat medium such that the heat medium having flowed out from each of the heat exchangers related to heat medium flows into the use side heat exchangers and a flow path through which the heat medium circulates is formed between all of the heat exchangers related to heat medium and each operating use side heat exchanger.