# US 2014/0150483 A1 · Air-conditioning apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0150483 A1 - Document ID: US20140150483A1 - Status: Published application - Kind: A1 - Application number: 14/235,898 - Filed: 2011-08-19 - Published: 2014-06-05 - Earliest claimed: 2011-08-19 - Assignees: Mitsubishi Electric Corporation - Inventors: Keisuke Takayama; Koji Azuma; Yuji Motomura - Web page: https://patentgrep.com/patent/US20140150483A1 ## CPC - F25B 30/02: of the compression type - F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) - F25B 25/005: {using primary and secondary systems} - F25B 49/00: Arrangement or mounting of control or safety devices - F25B 49/02: for compression type machines, plants or systems - F25B 2313/0231: with simultaneous cooling and heating - F25B 2313/0232: with bypasses - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract An air-conditioning apparatus includes a plurality of intermediate heat exchangers performing the same function (as a condenser or an evaporator) and allows each intermediate heat exchanger to exchange heat between a refrigerant heated or cooled in a refrigeration cycle on a heat source side and a heat medium flowing through a heat medium circuit on a use side such that heat energy produced on the heat source side is transmitted to use side heat exchangers. A controller calculates the difference between a heat medium inlet temperature and a heat medium outlet temperature Two of the use side heat exchanger which is operating to obtain a heat medium temperature difference for the use side heat exchanger, and controls a heat medium flow control device such that the heat medium temperature difference reaches a target heat medium temperature difference. ## Claims ### Claim 1 An air-conditioning apparatus comprising: a refrigeration cycle in which a compressor, a refrigerant passage of at least one intermediate heat exchanger operating as a condenser or an evaporator, an expansion device, and a heat source side heat exchanger are connected by pipes and through which a refrigerant circulates; a heat medium circuit in which a heat medium passage of the intermediate heat exchanger, a heat medium circulating device, a use side heat exchanger, and a heat medium flow control device disposed corresponding to the use side heat exchanger are connected by pipes and through which a heat medium circulates; a controller configured to control the heat medium flow control device in order to adjust the flow rate of the heat medium flowing through the use side heat exchanger; a first heat medium temperature detecting device configured to detect the temperature of the heat medium flowing into the use side heat exchanger; and a second heat medium temperature detecting device disposed corresponding to the use side heat exchanger, the second heat medium temperature detecting device being configured to detect the temperature of the heat medium flowing out of the use side heat exchanger, wherein the controller calculates a heat medium temperature difference between a detected value of the first heat medium temperature detecting device and a detected value of the second heat medium temperature detecting device for the use side heat exchanger which is operating, and controls the heat medium flow control device such that the heat medium temperature difference reaches a target heat medium temperature difference, and wherein when the detected value of the first heat medium temperature detecting device deviates from a predetermined range, the controller changes the target heat medium temperature difference and controls the heat medium flow control device corresponding to at least one of the use side heat exchanger, which is operating, such that the heat medium temperature difference reaches the changed target heat medium temperature difference. ### Claim 2 (depends on 10) The air-conditioning apparatus of claim 10, wherein at least one of the plurality of intermediate heat exchangers operates as a condenser in the refrigeration cycle to allow the use side heat exchanger to perform a heating operation, and wherein at least one of the other of the plurality of intermediate heat exchangers operates as an evaporator in the refrigeration cycle to allow the use side heat exchanger to perform a cooling operation. ### Claim 3 (depends on 1) The air-conditioning apparatus of claim 1, wherein while the intermediate heat exchanger operates as a condenser in the refrigeration cycle, the controller increases the target heat medium temperature difference when the detected value of the first heat medium temperature detecting device is greater than an upper limit of the predetermined range, and reduces the target heat medium temperature difference when the detected value of the first heat medium temperature detecting device is less than a lower limit of the predetermined range. ### Claim 4 (depends on 1) The air-conditioning apparatus of claim 1, wherein while the intermediate heat exchangers each operate as an evaporator in the refrigeration cycle, the controller increases the target heat medium temperature difference when the detected value of the first heat medium temperature detecting device is less than a lower limit of the predetermined range, and reduces the target heat medium temperature difference when the detected value of the first heat medium temperature detecting device is greater than an upper limit of the predetermined range. ### Claim 5 (depends on 1) The air-conditioning apparatus of claim 1, wherein the heat medium flow control device is a flow control valve, wherein when the heat medium temperature difference is greater than the target heat medium temperature difference, the controller increases an opening degree of the flow control valve, and wherein when the heat medium temperature difference is less than the target heat medium temperature difference, the controller reduces the opening degree of the flow control valve. ### Claim 6 (depends on 1) The air-conditioning apparatus of claim 1, wherein when a heating load is greater than a cooling load, the controller controls a rotation speed of the compressor such that a condensing temperature of the refrigerant flowing through the intermediate heat exchanger operating as a condenser reaches a target condensing temperature. ### Claim 7 (depends on 1) The air-conditioning apparatus of claim 1, wherein when a cooling load is greater than a heating load, the controller controls a rotation speed of the compressor such that an evaporating temperature of the refrigerant flowing through the intermediate heat exchanger operating as an evaporator reaches a target evaporating temperature. ### Claim 8 (depends on 2) The air-conditioning apparatus of claim 2, wherein the heat source side heat exchanger includes a heat exchange amount adjustment device configured to adjust the amount of heat exchange, wherein when a heating load is greater than a cooling load, the controller allows the heat source side heat exchanger to operate as an evaporator, controls a rotation speed of the compressor such that a condensing temperature of the refrigerant flowing through the intermediate heat exchanger operating as a condenser reaches a target condensing temperature, and controls the heat exchange amount control device such that an evaporating temperature of the refrigerant flowing through the intermediate heat exchanger operating as an evaporator reaches a target evaporating temperature, and wherein when the cooling load is greater than the heating load, the controller allows the heat source side heat exchanger to operate as a condenser, controls the heat exchange amount control device such that the condensing temperature of the refrigerant flowing through the intermediate heat exchanger operating as a condenser reaches the target condensing temperature, and controls the rotation speed of the compressor such that the evaporating temperature of the refrigerant flowing through the intermediate heat exchanger operating as an evaporator reaches the target evaporating temperature. ### Claim 9 (depends on 1) The air-conditioning apparatus of claim 1, wherein the compressor is accommodated in a heat source unit, wherein the intermediate heat exchangers are separately accommodated in a plurality of relay units, wherein the controller is separated into a heat source unit control device provided for the heat source unit and relay unit control devices provided for the respective relay units, wherein the heat source unit control device controls a rotation speed of the compressor, and wherein each of the relay unit control devices controls the flow rate of the heat medium flowing through the intermediate heat exchanger accommodated in the corresponding relay unit for which the relay unit control device is provided. ### Claim 10 (depends on 1) The air-conditioning apparatus of claim 1, wherein the at least one intermediate heat exchanger includes a plurality of intermediate heat exchangers, and the heat medium circuit is connected to each of the plurality of intermediate heat exchangers. ### Claim 11 (depends on 10) The air-conditioning apparatus of claim 10, wherein at least two of the plurality of intermediate heat exchangers simultaneously serve a single function as a condenser or an evaporator.