Air Conditioning Equipment

Abstract

This air-conditioning device comprises: an outdoor unit which has a compressor that causes a refrigerant to circulate in a refrigerant circuit, and which has an outdoor heat exchanger in which the refrigerant flows; a plurality of heat-medium heat exchanger units which have a heat-medium heat exchanger that exchanges heat between the refrigerant and a heat medium different from the refrigerant, and which have a pump that causes the heat medium to circulate in a heat medium circuit; a plurality of indoor units having an indoor heat exchanger in which the heat medium flows and arranged in an air-conditioned space; and a relay unit that is interposed between the outdoor unit and the plurality of heat-medium heat exchanger units, that distributes refrigerant flowing in from the outdoor unit to a plurality of flow channels, and that merges refrigerant flowing in from the plurality of heat-medium heat exchanger units. The plurality of heat-medium heat exchanger units are provided such that at least one unit is provided to each air-conditioned space where at least an indoor unit is disposed, and is connected to the indoor unit disposed in the corresponding air-conditioned space. The connected indoor unit operates as a condenser when performing a heating operation and operates as an evaporator when performing a cooling operation.

Description

[Technical field]

[0001] The present disclosure relates to an air-conditioning apparatus that is applied to, for example, a multi-air conditioner for a building. [Background technology]

[0002] Conventionally, there is known an air conditioner that connects a relay unit between an outdoor unit and an indoor unit, exchanges heat between a refrigerant supplied from the outdoor unit and a heat medium such as water in the relay unit, and circulates the heat medium to the indoor unit to cool or heat the air-conditioned space (for example, Patent Document 1). In Patent Document 1, a plurality of heat medium heat exchangers that are provided in the relay unit and exchange heat between the refrigerant and the heat medium are divided, some of which are used as condensers and the others as evaporators, thereby enabling simultaneous cooling and heating operation with a mixture of indoor units performing cooling operation and indoor units performing heating operation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 197044 Summary of the Invention [Problem to be solved by the invention]

[0004] In the air conditioner described in Patent Document 1, the multiple heat medium heat exchangers are divided so that the heat medium heat exchangers used as condensers and the heat medium heat exchangers used as evaporators are in a predetermined ratio during simultaneous cooling and heating operation. Therefore, when the cooling load or the heating load is significantly biased toward one side, the heat processing amount in the heat medium heat exchanger used as an evaporator or the heat medium heat exchanger used as a condenser becomes excessive, causing a drop in the evaporation temperature or an increase in the condensation temperature, resulting in a problem of a deterioration in energy saving and comfort.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an air conditioning apparatus that can suppress deterioration in energy saving and comfort when cooling and heating are operated simultaneously. [Means for solving the problem]

[0006] An air-conditioning apparatus according to the present disclosure comprises: an outdoor unit having a compressor that circulates a refrigerant in a refrigerant circuit and an outdoor heat exchanger through which the refrigerant flows; a plurality of heat medium heat exchanger units having a heat medium heat exchanger that exchanges heat between the refrigerant and a heat medium different from the refrigerant, and a pump that circulates the heat medium in the heat medium circuit; a plurality of indoor units arranged in an air-conditioned space, the indoor units including an indirect type indoor unit having a first indoor heat exchanger through which the heat medium flows, and a direct expansion type indoor unit having a second indoor heat exchanger through which the refrigerant flows; and a relay unit interposed between the outdoor unit, the plurality of heat medium heat exchanger units, and the direct expansion type indoor unit, and configured to divide the refrigerant flowing in from the outdoor unit into a plurality of flow paths and to merge the refrigerant flowing in from the plurality of heat medium heat exchanger units and the direct expansion type indoor unit, before The heat medium heat exchanger units are provided at least one for each of the air-conditioned spaces in which the indirect type indoor units are arranged, and are connected to the indirect type indoor units arranged in the corresponding air-conditioned spaces, and the connected indirect type indoor units operate as condensers during heating operation and operate as evaporators during cooling operation. The value obtained by dividing the rated capacity of the indirect type indoor unit having the largest rated capacity by its rated air volume is smaller than the value obtained by dividing the rated capacity of the direct expansion type indoor unit having the smallest rated capacity by its rated air volume. It is something. Effect of the Invention

[0007] According to the air conditioning device of the present disclosure, the heat medium heat exchanger units are provided at least one for each air-conditioned space in which an indoor unit is arranged, and are connected to the indoor unit arranged in the corresponding air-conditioned space, and the connected indoor unit operates as a condenser during heating operation and as an evaporator during cooling operation. Therefore, even if the cooling load or the heating load is significantly biased during simultaneous cooling and heating operation, the heat medium heat exchanger unit can be switched to operate as a condenser or an evaporator depending on the connected indoor unit. By doing so, the condenser and the evaporator can be operated at an appropriate ratio depending on the load, and the heat processing amount in the heat medium heat exchanger is prevented from becoming excessive, which prevents the evaporation temperature from decreasing or the condensation temperature from increasing, thereby preventing deterioration in energy saving and comfort. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of an air conditioning apparatus according to a first embodiment. [Diagram 2] 1 is a circuit diagram of an air conditioner according to a first embodiment. [Diagram 3] FIG. 4 is a schematic configuration diagram of a modified example of the air conditioning apparatus according to the first embodiment. [Figure 4] FIG. 3 is a diagram showing a flow of refrigerant during cooling operation of the air conditioner according to the first embodiment. [Diagram 5] FIG. 3 is a diagram showing a flow of refrigerant during heating operation of the air conditioner according to the first embodiment. [Figure 6] 4 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high cooling ratio in the air conditioner according to Embodiment 1. FIG. [Figure 7] FIG. 4 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in the air conditioner according to the first embodiment. [Figure 8] FIG. 11 is a circuit diagram of an air conditioner according to a second embodiment. [Figure 9] FIG. 11 is a diagram showing a flow of refrigerant during cooling operation of an air-conditioning apparatus according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing a flow of refrigerant during heating operation of an air conditioner according to embodiment 2. [Figure 11] FIG. 11 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high cooling ratio in an air-conditioning apparatus according to embodiment 2. [Figure 12] FIG. 11 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in an air conditioner according to embodiment 2. [Figure 13] FIG. 11 is a schematic configuration diagram of an air conditioning apparatus according to a third embodiment. [Figure 14] FIG. 11 is a circuit diagram of an air conditioner according to embodiment 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described with reference to the drawings. In each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the specification. In addition, the forms of the components shown in the entire specification are merely examples and are not limited to these descriptions. Furthermore, the size relationships of the components in the following drawings may differ from the actual ones.

[0010] Embodiment 1 FIG. 1 is a schematic configuration diagram of an air conditioner 100 according to the first embodiment. The air conditioner 100 according to the first embodiment is installed in a building 500, such as a building, and conditions a plurality of air-conditioned spaces 505-509 in the building 500. As shown in FIG. 1, the building 500 in which the air conditioner 100 is installed includes non-air-conditioned spaces 501-504 that are not subject to air conditioning, and air-conditioned spaces 505-509 that are subject to air conditioning. The non-air-conditioned spaces 501 and 502 are, for example, above the ceiling. The non-air-conditioned spaces 503 and 504 are, for example, machine rooms. The air-conditioned space 505 is, for example, a large living room. The air-conditioned spaces 506-509 are, for example, small living rooms.

[0011] The air conditioner 100 includes an outdoor unit 101, an indoor unit 104, a heat medium heat exchanger unit 103, and a relay unit 102 that is connected between the outdoor unit 101 and the heat medium heat exchanger unit 103 and is a flow dividing unit that divides a refrigerant into a plurality of flow paths. In the first embodiment, one outdoor unit 101 and one relay unit 102 are provided, and one indoor unit 104 is provided for each of the air-conditioned spaces 505 to 509, and a heat medium heat exchanger unit 103 is provided to be paired with the indoor unit 104. In other words, in the first embodiment, the air conditioner 100 includes one outdoor unit 101, one relay unit 102, five indoor units 104 (indoor units 104a to 104e in FIG. 2 to be described later), and five heat medium heat exchanger units 103 (heat medium heat exchanger units 103a to 103e in FIG. 2 to be described later). It should be noted that the heat medium heat exchanger unit 103 does not have to be paired with the indoor unit 104, and one unit may be provided for a plurality of indoor units 104.

[0012] FIG. 2 is a circuit diagram of the air conditioner 100 according to the first embodiment. As shown in FIG. 2, the outdoor unit 101 and the relay unit 102 are connected by refrigerant main pipes 105a and 105b through which a refrigerant flows. Here, the refrigerant main pipe 105a is a high-pressure pipe through which a high-pressure refrigerant flows, and the refrigerant main pipe 105b is a low-pressure pipe through which a low-pressure refrigerant flows. The relay unit 102 and the heat medium heat exchanger units 103a to 103e are connected by refrigerant branch pipes 106a to 106e through which a refrigerant flows. The heat medium heat exchanger units 103a to 103e and the indoor units 104a to 104e are connected by heat medium pipes 107a to 107e through which a heat medium flows. Each of the heat medium heat exchanger units 103a to 103e is connected in parallel to the relay unit 102. Each of the indoor units 104a to 104e is connected in series to each of the heat medium heat exchanger units 103a to 103e. The heat generated in the outdoor unit 101 is transferred to the heat medium heat exchanger units 103a-103e via the relay unit 102 by the refrigerant flowing through the refrigerant main pipes 105a and 105b. The heat converted in the heat medium heat exchanger units 103a-103e is transferred to the indoor units 104a-104e by the heat medium flowing through the heat medium pipes 107a-107e. That is, the indoor units 104a-104e cool or heat the air-conditioned space by the heat medium to which heat is transferred from the refrigerant supplied from the outdoor unit 101. The heat medium heat exchanger units 103a-103e are installed in non-air-conditioned spaces 501 and 502, which are different from the air-conditioned spaces 505-509 in which the indoor units 104a-104e are installed. This is because the heat medium heat exchanger units 103a-103e through which the refrigerant flows are disposed in locations different from the air-conditioned spaces 505-509, thereby preventing the refrigerant from leaking into the air-conditioned spaces 505-509.

[0013] The refrigerants used in the air conditioner 100 are, for example, a single refrigerant such as R32, a pseudo-azeotropic mixture refrigerant such as R410A, a refrigerant or mixture thereof that contains a double bond or CF3I in its chemical formula and is considered to have a relatively small global warming potential, or a natural refrigerant such as CF3I, CO2 or propane.The heat medium used in the air conditioner 100 is, for example, water, brine (antifreeze), a mixture of brine and water, or a mixture of water and an additive with high corrosion prevention effect.

[0014] FIG. 3 is a schematic configuration diagram of a modified example of the air conditioning apparatus 100 according to the first embodiment. The number of the relay units 102, the indoor units 104, and the heat medium heat exchanger units 103 is not limited to the above. The number of the heat medium heat exchanger units 103 may be equal to or greater than the number of the air-conditioned spaces 505-509 and equal to or less than the number of the indoor units 104. Here, even when multiple indoor units 104 are installed in the same room, one room is defined as one air-conditioned space. The air conditioning apparatus 100 may be configured as shown in FIG. 3, for example. In the modified example of the first embodiment, one outdoor unit 101 is provided, and two relay units 102 are provided. Furthermore, two indoor units 104 are provided in the air-conditioned space 505, which is a large room, and one indoor unit 104 is provided for each of the air-conditioned spaces 506-509, which are small rooms. Further, one heat medium heat exchanger unit 103 is provided for two indoor units 104 provided in the air-conditioned space 505, and further, a heat medium heat exchanger unit 103 is provided so as to be paired with the indoor units 104 provided in the air-conditioned spaces 506 to 509. That is, in the modified example of the first embodiment, the air-conditioning apparatus 100 includes one outdoor unit 101, two relay units 102, six indoor units 104, and five heat medium heat exchanger units 103. Note that one room is not limited to being defined as one air-conditioned space, and a plurality of rooms, such as two rooms, may be defined as one air-conditioned space. For example, the air-conditioned spaces 508 and 509 shown in FIG. 3 may be defined as one air-conditioned space, and in this case, one heat medium heat exchanger unit 103 is provided for two indoor units 104 provided in the one air-conditioned space. In other words, one air-conditioned space is made up of one or more rooms, and for that one air-conditioned space, one or more indoor units 104 are provided, and one or more heat medium heat exchanger units 103 are provided.

[0015] As shown in Fig. 2, the air conditioner 100 includes a refrigerant circuit through which a refrigerant circulates, and a heat medium circuit through which a heat medium circulates. The refrigerant circuit is configured by connecting an outdoor unit 101, heat medium heat exchanger units 103a-103e, and a relay unit 102 via refrigerant main pipes 105a, 105b and refrigerant branch pipes 106a-106e. The heat medium circuit is configured by connecting heat medium heat exchanger units 103a-103e and indoor units 104a-104e via heat medium pipes 107a-107e.

[0016] The outdoor unit 101 includes a compressor 11, a flow path switching valve 12, an outdoor heat exchanger 13, an outdoor fan 14, a flow rate adjustment valve 15, check valves 16a to 16d, an accumulator 17, and an outdoor control device 18.

[0017] The compressor 11 sucks in low-temperature and low-pressure gas refrigerant, compresses it, and discharges high-temperature and high-pressure gas refrigerant. The refrigerant is circulated in a refrigerant circuit by the compressor 11. The compressor 11 is, for example, an inverter-type compressor whose capacity is controllable.

[0018] The flow path switching valve 12 is, for example, a four-way valve. The flow path switching valve 12 switches the flow path of the refrigerant discharged from the compressor 11 depending on the operation of the indoor units 104a to 104e. The flow path switching valve 12 switches to the flow path shown by the solid line in Fig. 2 during cooling operation, and switches to the flow path shown by the dashed line in Fig. 2 during heating operation. The flow path switching valve 12 may be a combination of a three-way valve or a two-way valve.

[0019] The outdoor heat exchanger 13 is, for example, a fin-tube type heat exchanger. The outdoor heat exchanger 13 exchanges heat between the air supplied by the outdoor fan 14 and the refrigerant. The outdoor heat exchanger 13 operates as a condenser during cooling operation, condensing and liquefying the refrigerant. The outdoor heat exchanger 13 operates as an evaporator during heating operation, evaporating and gasifying the refrigerant.

[0020] The outdoor fan 14 is, for example, a propeller fan. The outdoor fan 14 supplies air around the outdoor unit 101 to the outdoor heat exchanger 13. The rotation speed of the outdoor fan 14 is controlled by the outdoor control device 18, whereby the condensation capacity or evaporation capacity of the outdoor heat exchanger 13 is controlled.

[0021] The flow rate control valve 15 reduces the pressure of the refrigerant to expand it. The flow rate control valve 15 is, for example, an electronic expansion valve that can adjust the aperture of the throttle, and by adjusting the aperture, the pressure of the refrigerant flowing into the heat medium heat exchanger units 103a to 103e is controlled during cooling operation, and the pressure of the refrigerant flowing into the outdoor heat exchanger 13 is controlled during heating operation.

[0022] The check valves 16a to 16d allow the refrigerant to flow only in a predetermined direction. The check valve 16a allows the refrigerant to flow only in the direction from the outdoor heat exchanger 13 to the relay unit 102. The check valve 16b allows the refrigerant to flow only in the direction from the relay unit 102 to the flow path switching valve 12. The check valve 16c allows the refrigerant to flow only in the direction from the flow path switching valve 12 to the relay unit 102. The check valve 16d allows the refrigerant to flow only in the direction from the relay unit 102 to the outdoor heat exchanger 13.

[0023] The accumulator 17 is provided on the suction side of the compressor 11, and has a function of separating the liquid refrigerant and the gas refrigerant, and a function of storing surplus refrigerant.

[0024] The outdoor control device 18 controls the operations of the compressor 11, the flow path switching valve 12, the outdoor fan 14, and the flow rate adjustment valve 15. The outdoor control device 18 is composed of a processing device including a memory for storing data and programs required for control and a CPU for executing the programs, or dedicated hardware such as an ASIC or an FPGA, or both. The outdoor control device 18 controls the drive frequency of the compressor 11, the flow path of the flow path switching valve 12, the rotation speed of the outdoor fan 14, and the opening degree of the flow rate adjustment valve 15 based on the detection results of a pressure sensor (not shown) mounted on the outdoor unit 101 for detecting the refrigerant pressure and a temperature sensor (not shown) for detecting the refrigerant temperature or the outdoor air temperature. The temperature sensor is, for example, a thermistor. The outdoor control device 18 can perform data communication with the heat medium control devices 34a-34e mounted in the heat medium heat exchanger units 103a-103e, the indoor control devices 43a-43e mounted in the indoor units 104a-104e, and the control device 29 mounted in the relay device 102.

[0025] The relay unit 102 includes an inter-refrigerant heat exchanger 21, a flow control valve 22, an inter-refrigerant heat exchanger 23, a flow control valve 24, cooling check valves 25a to 25e, heating check valves 26a to 26e, cooling solenoid valves 27a to 27e, heating solenoid valves 28a to 28e, and control devices 29a to 29e.

[0026] The inter-refrigerant heat exchangers 21, 23 are, for example, double-tube, plate, or shell-and-tube heat exchangers. The inter-refrigerant heat exchangers 21, 23 exchange heat between refrigerants. The flow rate control valves 22, 24 are solenoid valves whose opening degree is variably controlled. The flow rate control valve 22 is connected in series with the inter-refrigerant heat exchanger 21 and adjusts the flow rate of the heat medium flowing through the inter-refrigerant heat exchanger 21. The flow rate control valve 24 is connected in parallel with the cooling check valves 25a to 25e and adjusts the flow rate of the heat medium flowing through the inter-refrigerant heat exchanger 23 and the inter-refrigerant heat exchanger 21 downstream of the cooling solenoid valves 27a to 27e.

[0027] The cooling check valves 25a to 25e and the heating check valves 26a to 26e allow the refrigerant to flow only in a predetermined direction. The cooling check valves 25a to 25d allow the refrigerant flowing into the heat medium heat exchanger units 103a to 103e to flow during cooling operation. The heating check valves 26a to 26d allow the refrigerant flowing out of the heat medium heat exchanger units 103a to 103e to flow during heating operation. The cooling solenoid valves 27a to 27e and the heating solenoid valves 28a to 28e are selectively controlled to open and close, and allow or not allow the refrigerant to flow. The cooling solenoid valves 27a to 27d are controlled to allow the refrigerant to flow during cooling operation and not allow the refrigerant to flow during heating operation. The heating solenoid valves 28a to 28d are controlled to allow the refrigerant to flow during heating operation and not allow the refrigerant to flow during cooling operation.

[0028] The control device 29 controls the operations of the flow rate control valves 22, 24, the cooling solenoid valve 27, and the heating solenoid valve 28. The control device 29 is composed of a processing device having a memory for storing data and programs required for control and a CPU for executing the programs, or dedicated hardware such as an ASIC or FPGA, or both.

[0029] The heat medium heat exchanger units 103a to 103e include flow rate adjustment valves 31a to 31e, heat medium heat exchangers 32a to 32e, pumps 33a to 33e, and heat medium control devices 34a to 34e.

[0030] The flow rate control valves 31a to 31e are electronic expansion valves whose openings are variably controlled. The flow rate control valves 31a to 31e are connected in series to the heat medium heat exchangers 32a to 32e, and reduce the pressure of the refrigerant flowing out of the heat medium heat exchangers 32a to 32e or the refrigerant flowing into the heat medium heat exchangers 32a to 32e, causing it to expand.

[0031] The heat medium heat exchangers 32a to 32e are, for example, plate-type heat exchangers. The heat medium heat exchangers 32a to 32e exchange heat between the refrigerant supplied from the outdoor unit 101 and the heat medium circulated by the pumps 33a to 33e. As a result, heat stored in the refrigerant supplied from the outdoor unit 101 is transferred to the heat medium. The heat medium heat exchangers 32a to 32e operate as condensers during heating operation, condensing and liquefying the refrigerant. Also, the heat medium heat exchangers 32a to 32e operate as evaporators during cooling operation, evaporating and gasifying the refrigerant.

[0032] The pumps 33a to 33e are, for example, inverter-type centrifugal pumps whose capacity can be controlled. The pumps 33a to 33e have motors driven by an inverter, and are driven using the motors as a power source to apply pressure to the heat medium and circulate it through the heat medium circuit. In FIG. 2, the pumps 33a to 33e are arranged so that the refrigerant flow and the heat medium flow in the heating operation are opposed to each other to form a heating counterflow, but they may also be arranged so that the refrigerant flow and the heat medium flow in the cooling operation are opposed to each other to form a cooling counterflow.

[0033] The heat medium control devices 34a to 34e control the operations of the flow rate regulating valves 31a to 31e and the pumps 33a to 33e. The heat medium control devices 34a to 34e are configured with a processing device including a memory for storing data and programs required for control and a CPU for executing the programs, or with dedicated hardware such as an ASIC or FPGA, or both.

[0034] The indoor units 104a to 104e supply heat converted by the heat medium heat exchanger units 103a to 103e to the cooling load or heating load of the air-conditioned spaces 505 to 509. The indoor units 104a to 104e include indoor heat exchangers 41a to 41e, indoor fans 42a to 42e, and indoor control devices 43a to 43e.

[0035] The indoor heat exchangers 41a to 41e are, for example, fin-tube type heat exchangers. The indoor heat exchangers 41a to 41e exchange heat between the air supplied by the indoor fans 42a to 42e and a heat medium.

[0036] The indoor fans 42a-42e are, for example, cross-flow fans. The indoor fans 42a-42e supply air from the air-conditioned spaces 505-509 to the indoor heat exchangers 41a-41e. The rotation speeds of the indoor fans 42a-42e are controlled by the indoor control devices 43a-43e, thereby controlling the heating capacity or cooling capacity of the indoor heat exchangers 41a-41e.

[0037] The indoor control devices 43a to 43e control the operation of the indoor fans 42a to 42e. The indoor control devices 43a to 43e are configured as a processing device equipped with a memory for storing data and programs required for control and a CPU for executing the programs, or dedicated hardware such as an ASIC or FPGA, or both.

[0038] The air conditioner 100 according to the first embodiment performs cooling or heating operation based on instructions from a remote control (not shown) or the like to the indoor units 104a to 104e. Cooling operation and heating operation are achieved by switching the flow path switching valve 12 of the outdoor unit 101. The air conditioner 100 also achieves simultaneous cooling and heating operation by having some of the multiple indoor units 104a to 104e perform cooling operation and the others perform heating operation.

[0039] Fig. 4 is a diagram showing the flow of refrigerant during cooling operation of the air conditioning apparatus 100 according to embodiment 1. Solid arrows in Fig. 4 and Figs. 5 to 7 described later indicate the flow of refrigerant during cooling operation, and dashed arrows indicate the flow of refrigerant during heating operation. The flow of refrigerant during each operation is explained below.

[0040] In cooling operation, high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow path switching valve 12 and flows into the outdoor heat exchanger 13. The refrigerant that flows into the outdoor heat exchanger 13 exchanges heat with air supplied by the outdoor fan 14, and is condensed and liquefied, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the outdoor heat exchanger 13 flows into the relay unit 102 through the flow control valve 15, the check valve 16a, and the main refrigerant pipe 105a.

[0041] The low-temperature, high-pressure liquid refrigerant that has flowed into the relay unit 102 is further cooled by heat exchange with the refrigerant in the refrigerant-to-refrigerant heat exchangers 21, 23. Thereafter, a portion of the low-temperature, high-pressure liquid refrigerant is bypassed, and most of it flows through the cooling check valves 25a-25e and the refrigerant branch pipes 106a-106e into the heat medium heat exchanger units 103a-103e. On the other hand, the bypassed low-temperature, high-pressure liquid refrigerant is depressurized by the flow rate adjustment valve 24 to become a low-temperature, low-pressure two-phase refrigerant, and then exchanges heat with the refrigerant in the refrigerant-to-refrigerant heat exchangers 23, 21 to evaporate and become a high-temperature, low-pressure gas refrigerant.

[0042] The low-temperature, high-pressure liquid refrigerant flowing into the heat medium heat exchanger units 103a-103e is depressurized by the flow rate control valves 31a-31e to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat medium heat exchangers 32a-32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a-32e operating as evaporators, evaporating and vaporizing, becoming a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant flowing out of the heat medium heat exchangers 32a-32e passes through the refrigerant branch pipes 106a-106e and the cooling solenoid valves 27a-27e, then merges with the bypassed high-temperature, low-pressure gas refrigerant, and flows into the outdoor unit 101 through the main refrigerant pipe 105b.

[0043] The high-temperature, low-pressure gas refrigerant that has flowed into the outdoor unit 101 passes through the check valve 16b, the flow path switching valve 12, and the accumulator 17, and returns to the compressor 11 again.

[0044] 5 is a diagram showing the flow of refrigerant during heating operation of the air conditioner 100 according to embodiment 1. During heating operation, high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow path switching valve 12, the check valve 16c, and the main refrigerant pipe 105a, and flows into the relay unit 102. The gas refrigerant that has flowed into the relay unit 102 passes through heating solenoid valves 28a-28e and refrigerant branch pipes 106a-106e, and flows into the heat medium heat exchanger units 103a-103e.

[0045] The high-temperature, high-pressure gas refrigerant that has flowed into the heat medium heat exchanger units 103a-103e flows into the heat medium heat exchangers 32a-32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a-32e that operate as condensers, and is condensed and liquefied to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that has flowed out of the heat medium heat exchangers 32a-32e is decompressed by the flow control valves 31a-31e to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the outdoor unit 101 through the refrigerant branch pipes 106a-106e, the heating check valves 26a-26e, the inter-refrigerant heat exchangers 23, the flow control valves 24, the inter-refrigerant heat exchangers 23, the inter-refrigerant heat exchangers 21, and the main refrigerant pipe 105b.

[0046] The low-temperature, low-pressure two-phase refrigerant that has flowed into the outdoor unit 101 passes through the check valve 16d and the flow rate control valve 15, and flows into the outdoor heat exchanger 13. The refrigerant that has flowed into the outdoor heat exchanger 13 exchanges heat with air supplied by the outdoor fan 14, and evaporates to become a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that has flowed out of the outdoor heat exchanger 13 passes through the flow path switching valve 12 and the accumulator 17, and returns to the compressor 11 again.

[0047] Fig. 6 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high cooling ratio in the air-conditioning apparatus 100 according to embodiment 1. In simultaneous cooling and heating operation with a high cooling ratio, in which the ratio of indoor units 104 in cooling operation is greater than that of indoor units 104 in heating operation, that is, in which the ratio of cooling is high, the heat medium heat exchanger unit 103 (heat medium heat exchanger units 103b to 103e in Fig. 6) connected to the indoor unit 104 in cooling operation (indoor units 104b to 104e in Fig. 6) operates as an evaporator, and the heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103a in Fig. 6) connected to the indoor unit 104 in heating operation (indoor unit 104a in Fig. 6) operates as a condenser.

[0048] In simultaneous cooling and heating operation with a high cooling ratio, high-temperature, high-pressure gas refrigerant discharged from compressor 11 flows into outdoor heat exchanger 13 through flow path switching valve 12. The refrigerant that flows into outdoor heat exchanger 13 exchanges heat with air supplied by outdoor fan 14, condenses and liquefies, and becomes medium-temperature, high-pressure two-phase refrigerant. The medium-temperature, high-pressure two-phase refrigerant that flows out of outdoor heat exchanger 13 flows into relay unit 102 through flow control valve 15, check valve 16a, and main refrigerant pipe 105a.

[0049] The medium-temperature, high-pressure two-phase refrigerant that flows into the relay unit 102 is separated into a gas-rich refrigerant and a liquid-rich refrigerant. The gas-rich refrigerant flows into the heat medium heat exchanger unit 103a through the heating solenoid valve 28a, and is condensed and liquefied by heat exchange with the heat medium in the heat medium heat exchanger 32a that operates as a condenser, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat medium heat exchanger 32a is decompressed by the flow rate control valve 31a to become a low-temperature, medium-pressure liquid or two-phase refrigerant, and then passes through the refrigerant branch pipe 106a and the heating check valve 26a to merge with the liquid-rich refrigerant that flows out of the flow rate control valve 22.

[0050] The liquid-rich refrigerant is cooled and condensed and liquefied in the refrigerant-to-refrigerant heat exchanger 21, becoming a low-temperature, high-pressure liquid. The low-temperature, high-pressure liquid is depressurized in the flow control valve 22, becoming a low-temperature, medium-pressure liquid or two-phase refrigerant, and then merges with the condensed and liquefied refrigerant in the heat medium heat exchanger 32a. Then, the low-temperature, medium-pressure liquid or two-phase refrigerant is cooled and condensed and liquefied in the refrigerant-to-refrigerant heat exchanger 23, becoming a low-temperature, medium-pressure liquid refrigerant.

[0051] The low-temperature medium-pressure liquid refrigerant flows through the cooling check valves 25b-25e and the refrigerant branch pipes 106b-106e into the heat medium heat exchanger units 103b-103e, where it is depressurized by the flow rate control valves 31b-31e to become a low-temperature low-pressure two-phase refrigerant. The low-temperature low-pressure two-phase refrigerant then flows into the heat medium heat exchangers 32b-32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32b-32e operating as evaporators, evaporating and vaporizing, becoming a high-temperature low-pressure gas refrigerant. The high-temperature low-pressure gas refrigerant flowing out of the heat medium heat exchangers 32b-32e flows into the outdoor unit 101 through the refrigerant branch pipes 106b-106e, the cooling solenoid valves 27b-27e, and the refrigerant main pipe 105b.

[0052] The high-temperature, low-pressure gas refrigerant that has flowed into the outdoor unit 101 passes through the check valve 16b, the flow path switching valve 12, and the accumulator 17, and returns to the compressor 11 again.

[0053] Fig. 7 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in the air conditioner 100 according to embodiment 1. In simultaneous cooling and heating operation with a high heating ratio, in which the ratio of indoor units 104 in heating operation is greater than that of indoor units 104 in cooling operation, that is, in which the ratio of heating is high, the heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103e in Fig. 7) connected to the indoor unit 104 in cooling operation (indoor unit 104e in Fig. 7) operates as an evaporator, and the heat medium heat exchanger unit 103 (heat medium heat exchanger units 103a to 103d in Fig. 7) connected to the indoor unit 104 in heating operation (indoor units 104a to 104d in Fig. 7) operates as a condenser.

[0054] In simultaneous cooling and heating operation with a high heating ratio, high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow path switching valve 12, the check valve 16c, and the main refrigerant pipe 105a, and flows into the relay unit 102. The gas refrigerant that has flowed into the relay unit 102 passes through heating solenoid valves 28a-28d and refrigerant branch pipes 106a-106d, and flows into the heat medium heat exchanger units 103a-103d.

[0055] The high-temperature, high-pressure gas refrigerant that has flowed into the heat medium heat exchanger units 103a-103d flows into the heat medium heat exchangers 32a-32d, and exchanges heat with the heat medium in the heat medium heat exchangers 32a-32d that operate as condensers, and is condensed and liquefied to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that has flowed out of the heat medium heat exchangers 32a-32d is depressurized by the flow rate control valves 31a-31d to become a low-temperature, medium-pressure liquid or two-phase refrigerant. The low-temperature, medium-pressure liquid or two-phase refrigerant then passes through the refrigerant branch pipes 106a-106d and the heating check valves 26a-26d, and is cooled in the refrigerant-to-refrigerant heat exchanger 23, where it is condensed and liquefied to become a low-temperature, medium-pressure liquid refrigerant. A portion of the low-temperature, medium-pressure liquid refrigerant is bypassed, and the majority is depressurized by the flow rate control valve 24 to become a low-temperature, low-pressure two-phase refrigerant, and is then heated in the refrigerant-to-refrigerant heat exchangers 23 and 21.

[0056] Meanwhile, the bypassed low-temperature medium-pressure liquid refrigerant passes through the cooling check valve 25e and the refrigerant branch pipe 106e and flows into the heat medium heat exchanger unit 103e. The low-temperature medium-pressure liquid refrigerant that flows into the heat medium heat exchanger unit 103e is depressurized by the flow rate control valve 31e to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat medium heat exchanger 32e, where it exchanges heat with the heat medium in the heat medium heat exchanger 32e operating as an evaporator and evaporates to become a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant then flows into the relay unit 102 through the refrigerant branch pipe 106e.

[0057] The low-temperature, low-pressure two-phase refrigerant heated in the refrigerant heat exchangers 23, 21 merges with the high-temperature, low-pressure gas refrigerant that has passed through the cooling solenoid valve 27a, and then flows into the outdoor unit 101 through the main refrigerant pipe 105b.

[0058] The low-temperature, low-pressure two-phase refrigerant that has flowed into the outdoor unit 101 passes through the check valve 16d and the flow rate control valve 15, and flows into the outdoor heat exchanger 13. The refrigerant that has flowed into the outdoor heat exchanger 13 exchanges heat with air supplied by the outdoor fan 14, and evaporates to become a high-temperature, low-pressure gas or two-phase refrigerant. The high-temperature, low-pressure gas or two-phase refrigerant that has flowed out of the outdoor heat exchanger 13 passes through the flow path switching valve 12 and the accumulator 17, and returns to the compressor 11 again.

[0059] As described above, the air conditioning apparatus 100 according to the first embodiment includes an outdoor unit 101 having a compressor 11 that circulates a refrigerant in a refrigerant circuit and an outdoor heat exchanger 13 through which the refrigerant flows, a plurality of heat medium heat exchanger units 103a-103e having heat medium heat exchangers 32a-32e that exchange heat between the refrigerant and a heat medium different from the refrigerant and pumps 33a-33e that circulate the heat medium in the heat medium circuit, a plurality of indoor units 104a-104e having indoor heat exchangers 41a-41e through which the heat medium flows and arranged in air-conditioned spaces 505-509, and a relay unit 102 that is interposed between the outdoor unit 101 and the plurality of heat medium heat exchanger units 103a-103e and divides the refrigerant flowing in from the outdoor unit 1 into a plurality of flow paths and joins the refrigerant flowing in from the plurality of heat medium heat exchanger units 103a-103e. Further, the plurality of heat medium heat exchanger units 103a-103e are provided corresponding to at least each of the air-conditioned spaces 505-509 in which the indoor units 104a-104e are arranged, and are connected to the indoor units 104a-104e arranged in the corresponding air-conditioned spaces 505-509, so that the connected indoor units 104a-104e function as condensers during heating operation and as evaporators during cooling operation.

[0060] According to the air conditioner 100 of the first embodiment, the heat medium heat exchanger units 103a-103e are provided corresponding to at least each of the air-conditioned spaces 505-509 in which the indoor units 104a-104e are arranged, and are connected to the indoor units 104a-104e arranged in the corresponding air-conditioned spaces 505-509, and the connected indoor units 104a-104e operate as condensers during heating operation and operate as evaporators during cooling operation. Therefore, even if the cooling load or the heating load is significantly biased during simultaneous cooling and heating operation, the heat medium heat exchanger units 103a-103e can be switched to operate as condensers or evaporators according to the connected indoor units 104a-104e. This allows the condenser and evaporator to operate in an appropriate ratio according to the load, thereby preventing an excessive amount of heat treatment in the heat medium heat exchangers 32a to 32e, which would result in a drop in evaporation temperature or an increase in condensation temperature, and thereby preventing a decrease in energy saving and comfort.

[0061] In addition, since the indoor unit 104 is configured so that the refrigerant does not flow therethrough, leakage of the refrigerant from the indoor unit 104 can be prevented.

[0062] Moreover, in the air conditioning apparatus 100 according to the first embodiment, the multiple heat medium heat exchanger units 103a-103e are arranged in the non-conditioned spaces 501-504.

[0063] According to the air conditioning apparatus 100 of embodiment 1, the heat medium heat exchanger units 103a-103e are arranged in the non-air-conditioned spaces 501-504, so that leakage of refrigerant from the heat medium heat exchanger units 103a-103e to the air-conditioned spaces 505-509 can be prevented.

[0064] Furthermore, in the air conditioning apparatus 100 according to the first embodiment, the multiple heat medium heat exchanger units 103a to 103e are provided so as to form pairs with the indoor units 104a to 104e.

[0065] According to the air conditioner 100 of the first embodiment, since the heat medium heat exchanger units 103a-103e are provided in pairs with the indoor units 104a-104e, the condenser and the evaporator can be operated at a more appropriate ratio according to the load. As a result, the amount of heat treatment in the heat medium heat exchangers 32a-32e is prevented from becoming excessive, which leads to a drop in the evaporation temperature or an increase in the condensation temperature, and thus a deterioration in energy saving and comfort can be prevented.

[0066] Embodiment 2 Hereinafter, the second embodiment will be described, but explanations of parts that overlap with the first embodiment will be omitted, and parts that are the same as or equivalent to the first embodiment will be given the same reference numerals.

[0067] In the second embodiment, the configurations of the outdoor unit 101A and the relay unit 102A are different from those in the first embodiment. Also, in the second embodiment, the configuration of the refrigerant piping that connects the outdoor unit 101A and the relay unit 102A is different from that in the first embodiment.

[0068] FIG. 8 is a circuit diagram of an air conditioner 100A according to the second embodiment. As shown in FIG. 8, the outdoor unit 101A and the relay unit 102A are connected by refrigerant main pipes 105c-105e through which the refrigerant flows. Here, the refrigerant main pipe 105c is a high-pressure gas pipe through which a high-pressure gas refrigerant flows, the refrigerant main pipe 105d is a low-pressure gas pipe through which a low-pressure gas refrigerant flows, and the refrigerant main pipe 105e is a liquid pipe through which a liquid refrigerant flows. The relay unit 102A and the heat medium heat exchanger units 103a-103e are connected by refrigerant branch pipes 106a-106e through which the refrigerant flows. The heat medium heat exchanger units 103a-103e and the indoor units 104a-104e are connected by heat medium pipes 107a-107e through which the heat medium flows. Each of the heat medium heat exchanger units 103a-103e is connected in parallel to the relay unit 102A. Each of the indoor units 104a-104e is connected in series with each of the heat medium heat exchanger units 103a-103e. The heat generated in the outdoor unit 101A is transferred to the heat medium heat exchanger units 103a-103e via the relay unit 102A by the refrigerant flowing through the refrigerant main pipes 105c-105e. The heat converted in the heat medium heat exchanger units 103a-103e is transferred to the indoor units 104a-104e by the heat medium flowing through the heat medium pipes 107a-107e. In other words, the indoor units 104a-104e cool or heat the air-conditioned spaces 505-509 by the heat medium to which heat is transferred from the refrigerant supplied from the outdoor unit 101A.

[0069] The outdoor unit 101A includes a compressor 11, flow path switching valves 12a and 12b, outdoor heat exchangers 13a and 13b, an outdoor fan 14, flow control valves 15a and 15b, an accumulator 17, and an outdoor control device 18. The relay unit 102A includes a refrigerant heat exchanger 23, a flow control valve 24, cooling check valves 25a to 25e, heating check valves 26a to 26e, cooling solenoid valves 27a to 27e, heating solenoid valves 28a to 28e, and control devices 29a to 29e. The other configurations are the same as those in the first embodiment, so the description will be omitted.

[0070] Fig. 9 is a diagram showing the flow of refrigerant during cooling operation of the air conditioning apparatus 100A according to embodiment 2. In Fig. 9 and Figs. 10 to 12 described later, solid arrows indicate the flow of refrigerant during cooling operation, and dashed arrows indicate the flow of refrigerant during heating operation. The flow of refrigerant during each operation is explained below.

[0071] In cooling operation, part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows through the flow path switching valve 12a into the outdoor heat exchanger 13a, and the rest flows through the flow path switching valve 12b into the outdoor heat exchanger 13b. The refrigerant that flows into the outdoor heat exchangers 13a and 13b exchanges heat with air supplied by the outdoor fan 14, condenses and liquefies, and becomes a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the outdoor heat exchangers 13a and 13b pass through the flow rate control valves 15a and 15b, respectively, and then merge, and flow through the main refrigerant pipe 105e into the relay unit 102A.

[0072] The low-temperature, high-pressure liquid refrigerant that has flowed into the relay unit 102A exchanges heat with the refrigerant in the refrigerant-to-refrigerant heat exchanger 23, condenses, and is further cooled. Then, a portion of the low-temperature, high-pressure liquid refrigerant is bypassed, and most of it flows through the cooling check valves 25a-25e and the refrigerant branch pipes 106a-106e and flows into the heat medium heat exchanger units 103a-103e. On the other hand, the bypassed low-temperature, high-pressure liquid refrigerant is depressurized by the flow rate adjustment valve 24 to become a low-temperature, low-pressure two-phase refrigerant, and then exchanges heat with the refrigerant in the refrigerant-to-refrigerant heat exchanger 23 to evaporate and become a high-temperature, low-pressure gas refrigerant.

[0073] The low-temperature, high-pressure liquid refrigerant flowing into the heat medium heat exchanger units 103a-103e is depressurized by the flow rate control valves 31a-31e to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat medium heat exchangers 32a-32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a-32e operating as evaporators, evaporating and becoming a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant flowing out of the heat medium heat exchangers 32a-32e passes through the refrigerant branch pipes 106a-106e and the cooling solenoid valves 27a-27e, merges with the bypassed high-temperature, low-pressure gas refrigerant, and then flows into the outdoor unit 101A through the refrigerant main pipe 105d.

[0074] The high-temperature, low-pressure gas refrigerant that has flowed into the outdoor unit 101A passes through the flow path switching valve 12a and the accumulator 17, and returns to the compressor 11 again.

[0075] 10 is a diagram showing the flow of refrigerant during heating operation of the air conditioner 100A according to embodiment 2. In heating operation, part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the relay unit 102A through the flow path switching valve 12a and the main refrigerant pipe 105d, and the rest flows into the relay unit 102A through the main refrigerant pipe 105c. The part of the gas refrigerant that flows into the relay unit 102A flows through the cooling solenoid valves 27a-27e, merges with the rest of the gas refrigerant that has passed through the heating solenoid valves 28a-28e in the refrigerant branch pipes 106a-106e, and then flows into the heat medium heat exchanger units 103a-103e.

[0076] The high-temperature, high-pressure gas refrigerant that has flowed into the heat medium heat exchanger units 103a-103e flows into the heat medium heat exchangers 32a-32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a-32e that operate as condensers, and is condensed and liquefied to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that has flowed out of the heat medium heat exchangers 32a-32e is depressurized by the flow rate control valves 31a-31e to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the outdoor unit 101A through the refrigerant branch pipes 106a-106e, the heating check valves 26a-26e, and the main refrigerant pipe 105e.

[0077] A portion of the low-temperature, low-pressure two-phase refrigerant that has flowed into the outdoor unit 101A flows through the flow control valve 15a into the outdoor heat exchanger 13a, and the remainder flows through the flow control valve 15b into the outdoor heat exchanger 13b. The refrigerant that has flowed into the outdoor heat exchangers 13a and 13b exchanges heat with the air supplied by the outdoor fan 14, evaporates, and becomes a high-temperature, low-pressure gas refrigerant or a two-phase refrigerant. The high-temperature, low-pressure gas refrigerant or two-phase refrigerant that has flowed out of the outdoor heat exchangers 13a and 13b pass through the flow path switching valves 12a and 12b, respectively, and then merge, and pass through the accumulator 17 and return to the compressor 11 again.

[0078] Fig. 11 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high cooling ratio in air conditioner 100A according to embodiment 2. During simultaneous cooling and heating operation with a high cooling ratio, heat medium heat exchanger unit 103 (heat medium heat exchanger units 103b to 103e in Fig. 10) connected to indoor unit 104 (indoor units 104b to 104e in Fig. 10) performing cooling operation operates as an evaporator, and heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103a in Fig. 10) connected to indoor unit 104 (indoor unit 104a in Fig. 10) performing heating operation operates as a condenser.

[0079] In simultaneous cooling and heating operation with a high cooling ratio, part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the relay unit 102A through the refrigerant main pipe 105c, and the rest flows into the outdoor heat exchanger 13a through the flow path switching valve 12a. The refrigerant that flows into the relay unit 102A flows into the heat medium heat exchanger unit 103a through the heating solenoid valve 28a, and is condensed and liquefied by heat exchange with the heat medium in the heat medium heat exchanger 32a operating as a condenser, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant then flows into the relay unit 102A through the flow rate adjustment valve 31a.

[0080] Meanwhile, the refrigerant that flows into the outdoor heat exchanger 13a exchanges heat with the air supplied by the outdoor fan 14, and a part of the refrigerant is condensed and liquefied to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the outdoor heat exchanger 13a flows into the relay unit 102A through the flow control valve 15a and the main refrigerant pipe 105e. The low-temperature, high-pressure liquid refrigerant that flows into the relay unit 102A is merged with the low-temperature, high-pressure liquid refrigerant that has passed through the heating check valve 26a, and is then cooled in the refrigerant-to-refrigerant heat exchanger 23, condensed and liquefied to become a low-temperature, medium-pressure liquid refrigerant. A part of the low-temperature, medium-pressure liquid refrigerant is bypassed, and the majority flows into the heat medium heat exchanger units 103b to 103e through the cooling check valves 25b to 25e and the refrigerant branch pipes 106b to 106e. On the other hand, the bypassed low-temperature medium-pressure liquid refrigerant is reduced in pressure by the flow control valve 24 to become a low-temperature low-pressure two-phase refrigerant, and then exchanges heat with the refrigerant in the refrigerant heat exchanger 23 to evaporate and become a high-temperature low-pressure gas refrigerant.

[0081] The low-temperature medium-pressure liquid refrigerant flowing into the heat medium heat exchanger units 103b-103e is depressurized by the flow rate control valves 31b-31e to become a low-temperature low-pressure two-phase refrigerant. The low-temperature low-pressure two-phase refrigerant then flows into the heat medium heat exchangers 32b-32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32b-32e operating as evaporators, evaporating and vaporizing, becoming a high-temperature low-pressure gas refrigerant. The high-temperature low-pressure gas refrigerant flowing out of the heat medium heat exchangers 32b-32e passes through the refrigerant branch pipes 106b-106e and the cooling solenoid valves 27b-27e, merges with the bypassed high-temperature low-pressure gas refrigerant, and then flows into the outdoor unit 101A through the refrigerant main pipe 105d.

[0082] The high-temperature, low-pressure gas refrigerant that has flowed into the outdoor unit 101A passes through the flow path switching valve 12a and the accumulator 17, and returns to the compressor 11 again.

[0083] Fig. 12 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in air conditioning apparatus 100A according to embodiment 2. In simultaneous cooling and heating operation with a high heating ratio, heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103e in Fig. 12) connected to indoor unit 104 (indoor unit 104e in Fig. 12) performing cooling operation operates as an evaporator, and heat medium heat exchanger unit 103 (heat medium heat exchanger units 103a to 103d in Fig. 12) connected to indoor unit 104 (indoor units 104a to 104d in Fig. 12) performing heating operation operates as a condenser.

[0084] In simultaneous cooling and heating operation with a high heating ratio, high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the relay unit 102A through the main refrigerant pipe 105c. The high-temperature, high-pressure gas refrigerant that has flowed into the relay unit 102A flows into the heat medium heat exchanger units 103a-103d through the heating solenoid valves 28a-28d and the refrigerant branch pipes 106a-106d.

[0085] The high-temperature, high-pressure gas refrigerant that has flowed into the heat medium heat exchanger units 103a-103d flows into the heat medium heat exchangers 32a-32d, and exchanges heat with the heat medium in the heat medium heat exchangers 32a-32d that operate as condensers, condensing and liquefying the refrigerant to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that has flowed out of the heat medium heat exchangers 32a-32d is depressurized by the flow rate control valves 31a-31d to become a low-temperature, medium-pressure liquid or two-phase refrigerant. The low-temperature, medium-pressure liquid or two-phase refrigerant then passes through the refrigerant branch pipes 106a-106d and the heating check valves 26a-26d. The low-temperature, medium-pressure liquid or two-phase refrigerant that has passed through the heating check valves 26a-26d is partially bypassed, and most of it flows through the main refrigerant pipe 105e and into the outdoor unit 101A. The low-temperature medium-pressure liquid or two-phase refrigerant that flows into the outdoor unit 101A is decompressed by the flow control valve 15b to become a low-temperature low-pressure two-phase refrigerant. The low-temperature low-pressure two-phase refrigerant then flows into the outdoor heat exchanger 13a, where it exchanges heat with the air supplied by the outdoor fan 14 and evaporates, becoming a high-temperature low-pressure gas or two-phase refrigerant.

[0086] On the other hand, the bypassed low-temperature medium-pressure liquid or two-phase refrigerant flows into the heat medium heat exchanger unit 103e through the refrigerant-to-refrigerant heat exchanger 23, the cooling check valve 25e, and the refrigerant branch pipe 106e. The low-temperature medium-pressure liquid or two-phase refrigerant that flows into the heat medium heat exchanger unit 103e is decompressed by the flow rate control valve 31e to become a low-temperature low-pressure two-phase refrigerant. The low-temperature low-pressure two-phase refrigerant then flows into the heat medium heat exchanger 32e, where it exchanges heat with the heat medium in the heat medium heat exchanger 32e operating as an evaporator and evaporates to become a high-temperature low-pressure gas refrigerant. The high-temperature low-pressure gas refrigerant that flows out of the heat medium heat exchanger 32e flows into the outdoor unit 101A through the refrigerant branch pipe 106e, the cooling solenoid valve 27e, and the refrigerant main pipe 105d.

[0087] Then, the high-temperature, low-pressure gas or two-phase refrigerant passes through the flow path switching valve 12b, and then merges with the high-temperature, low-pressure gas refrigerant that has passed through the flow path switching valve 12a, passes through the accumulator 17, and returns to the compressor 11 again.

[0088] As described above, in the air conditioning apparatus 100A according to embodiment 2, the outdoor unit 101A and the relay unit 102A are connected by the three main refrigerant pipes 105c to 105e through which the refrigerant flows. The three main refrigerant pipes 105c to 105e are a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe.

[0089] In the air conditioning apparatus 100A according to the second embodiment, the outdoor unit 101A and the relay unit 102A are connected by the main refrigerant pipe 105c which is a high pressure gas pipe, the main refrigerant pipe 105d which is a low pressure gas pipe, and the main refrigerant pipe 105e which is a liquid pipe. In this way, the main refrigerant pipe 105e which is a liquid pipe that has a large effect on the refrigerant charge amount can be made thinner, and the refrigerant charge amount can be reduced.

[0090] This allows the relay unit 102A to be configured to include the refrigerant heat exchanger 23, the flow rate adjustment valve 24, the cooling check valve 25, the heating check valve 26, the cooling solenoid valve 27, the heating solenoid valve 28, and the control device 29. This relay unit 102A has fewer components than the relay unit 102 according to the first embodiment, so that the relay unit 102A can be made smaller in size, and the installation space can be secured and the degree of freedom in installation can be improved.

[0091] Embodiment 3 Hereinafter, the third embodiment will be described, but explanations of parts that overlap with the first and second embodiments will be omitted, and the same parts as or corresponding parts to the first and second embodiments will be given the same reference numerals.

[0092] The third embodiment differs from the first and second embodiments in that it includes a mixture of indoor units that are provided with a heat medium heat exchanger unit 103 and in which heat is indirectly transported by a refrigerant (hereinafter also referred to as an indirect type indoor unit), and indoor units that are not provided with a heat medium heat exchanger unit 103 and in which heat is directly transported by a refrigerant (hereinafter also referred to as a direct expansion type indoor unit).

[0093] FIG. 13 is a schematic configuration diagram of an air conditioner 100B according to the third embodiment. FIG. 14 is a circuit diagram of the air conditioner 100B according to the third embodiment. As shown in FIG. 13 and FIG. 14, the air conditioner 100B includes an outdoor unit 101B, an indoor unit, heat medium heat exchanger units 103Ba-103Bd, and a relay unit 102. In the third embodiment, one outdoor unit 101B and one relay unit 102 are provided, and one indoor unit is provided for each of the air-conditioned spaces 505-509. The heat medium heat exchanger units 103Ba-103Bd are provided to be paired with the indoor units (indirect type indoor units 104Ba-104Bd) provided in the air-conditioned spaces 505 and 507-509, but the heat medium heat exchanger unit 103 is not provided for the indoor unit (direct expansion type indoor unit 108) provided in the air-conditioned space 506. That is, in embodiment 3, the indoor units include a mixture of indirect type indoor units 104Ba-104Bd and direct expansion type indoor units 108, and the air conditioning apparatus 100B includes one outdoor unit 101, one relay unit 102, four indirect type indoor units 104Ba-104Bd, one direct expansion type indoor unit 108, and four heat medium heat exchanger units 103Ba-103Bd.

[0094] The outdoor unit 101 includes a compressor 11, a flow path switching valve 12, an outdoor heat exchanger 13, an outdoor fan 14, a flow control valve 15, check valves 16a to 16d, an accumulator 17, an outdoor control device 18, and a discharge pressure sensor 19 that detects the refrigerant pressure on the discharge side of the compressor 11. The heat medium heat exchanger units 103a to 103d include flow control valves 31a to 31d, heat medium heat exchangers 32a to 32d, pumps 33a to 33d, heat medium control devices 34a to 34d, gas side temperature sensors 91a to 91d that detect the refrigerant temperature at the inlets of the refrigerant sides of the heat medium heat exchangers 32a to 32d during heating operation, and liquid side temperature sensors 92a to 92d that detect the refrigerant temperature at the outlets of the refrigerant sides of the heat medium heat exchangers 32a to 32d during heating operation.

[0095] The indirect type indoor units 104Ba to 104Bd are equipped with indoor heat exchangers (hereinafter also referred to as first indoor heat exchangers) 41a to 41d, indoor fans 42a to 42d, and indoor control devices 43a to 43d. The direct expansion type indoor unit 108 is equipped with a flow control valve 81, an indoor heat exchanger (hereinafter also referred to as second indoor heat exchanger) 82, an indoor fan 83, an indoor control device 84, a gas side temperature sensor 85 that detects the refrigerant temperature at the inlet of the indoor heat exchanger 82 during heating operation, and a liquid side temperature sensor 86 that detects the refrigerant temperature at the outlet of the indoor heat exchanger 82 during heating operation. The other configurations are the same as those in the first embodiment, so the description will be omitted.

[0096] Furthermore, in the air conditioning apparatus 100B according to embodiment 3, the ratio of the maximum floor area of ​​the air-conditioned space in which the indirect indoor units 104Ba-104Bd can be installed to the total floor area of ​​the air-conditioned space in which all indoor units (= indirect indoor units 104Ba-104Bd + direct expansion indoor unit 108) are installed (hereinafter referred to as the indirect indoor unit ratio) is 73% or less.

[0097] Here, the indirect type indoor unit ratio was calculated based on the following formulas (1) to (3).

[0098] Indirect indoor unit ratio≦(A 全面積 -A 直膨 ) / A 全面積 (1) A 全面積 : Total floor area of ​​the air-conditioned space in which all indoor units are installed [m 2 ], A 直膨 : The maximum floor area [m2] in the air-conditioned space where the direct expansion type indoor unit is installed, where the refrigerant leaks without exceeding the lower flammability limit (LFL) 2 ]

[0099] A 全面積 =Q 冷房 / q···(2) Q 冷房 : Cooling capacity of air conditioner [kW], q: Unit heat load (0.128 kW / m 2 *Assumed office value)

[0100] A 直膨 = M / (h × LFL) (3) M: refrigerant amount (R32: 0.357 [kg / kW], R1234yf: 0.428 [kg / kW], R1234ze(E): 0.464 [kg / kW]), h: ceiling height (2.2 [m]), LFL R32 =0.307[kg / m 3 ], LFL 1234yf =0.289[kg / m 3 ], LFL R1234ze =0.303 [kg / m 3 ]

[0101] Moreover, based on the conditions shown in Tables 1 to 4 below, the indirect type indoor unit ratio was calculated using formulas (1) to (3).

[0102] Table 1 shows an example of a calculation of the indirect indoor unit ratio assuming a cooling capacity of 56 kW. [Table 1]

[0103] Table 2 shows an example of a trial calculation of the ratio of indirect type indoor units assuming a cooling capacity of 56 kW and taking into account the increase in the amount of refrigerant due to piping length. [Table 2]

[0104] Table 3 shows an example of a trial calculation of the indirect indoor unit ratio assuming a cooling capacity of 28 kW. [Table 3]

[0105] Table 4 shows an example of a trial calculation of the ratio of indirect type indoor units assuming a cooling capacity of 28 kW and taking into account the increase in the amount of refrigerant due to piping length. [Table 4]

[0106] As described above, if the indirect type indoor unit ratio is 73% or less, the required cooling capacity can be exhibited under any of the above conditions, and the LFL can be prevented from being exceeded even if the refrigerant leaks in the air-conditioned spaces 505-509 in which the direct expansion type indoor units 108 are installed. Therefore, the direct expansion type indoor units 108 can be installed in the air-conditioned spaces 505-509, such as large spaces where safety can be ensured even if the refrigerant leaks, or spaces in which a ventilation device (not shown) is installed.

[0107] Also, the value obtained by dividing the rated capacity of the indirect type indoor units 104Ba-104Bd, which has the largest rated capacity, by its rated air volume is smaller than the value obtained by dividing the rated capacity of the direct expansion type indoor unit 108, which has the smallest rated capacity, by its rated air volume. In other words, the performance of the indirect type indoor units 104Ba-104Bd is made higher than the performance of the direct expansion type indoor unit 108. By doing so, the performance difference between the indirect type indoor units 104Ba-104Bd and the direct expansion type indoor unit 108 is reduced, and the gap in temperature difference ΔT between the air temperature and refrigerant temperature in the air-conditioned spaces 505-509 that occurs between them can be eliminated.

[0108] Also, different control target values ​​for the degree of superheat and the degree of subcooling are set for the heat medium heat exchanger units 103Ba-103Bd and the direct expansion indoor unit 108. When any one or more of the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd connected to the indirect indoor units 104Ba-104Bd and the indoor heat exchanger 82 of the direct expansion indoor unit 108 operate as evaporators, the degree of superheat of the indoor heat exchanger 82 is controlled to be larger than the degree of superheat of the heat medium heat exchangers 32a-32d. Here, the degree of superheat of the heat medium heat exchangers 32a-32d is calculated by (detection values ​​of the gas side temperature sensors 91a-91d)-(detection values ​​of the liquid side temperature sensors 92a-92d). Moreover, the degree of superheat of the indoor heat exchanger 82 is calculated by (the detection value of the gas side temperature sensor 85)-(the detection value of the liquid side temperature sensor 86).

[0109] In addition, when one or more of the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd connected to the indirect indoor units 104Ba-104Bd and the indoor heat exchanger 82 of the direct expansion indoor unit 108 operate as condensers, the degree of subcooling of the indoor heat exchanger 82 is controlled to be larger than the degree of subcooling of the heat medium heat exchangers 32a-32d. Here, the degree of subcooling of the heat medium heat exchangers 32a-32d is calculated by (condensation temperature calculated based on the detection value of the discharge pressure sensor 19)-(detection value of the liquid side temperature sensors 92a-92d). In addition, the degree of subcooling of the indoor heat exchanger 82 is calculated by (condensation temperature calculated based on the detection value of the discharge pressure sensor 19)-(detection value of the liquid side temperature sensor 86).

[0110] Here, in the indirect indoor units 104Ba-104Bd, the heat generated in the outdoor unit 101B is transported by the refrigerant to the heat medium heat exchanger units 103Ba-103Bd, where it is transferred from the refrigerant to a heat medium, and then transported by the heat medium to the indirect indoor units 104Ba-104Bd. On the other hand, in the direct expansion indoor unit 108, the heat generated in the outdoor unit 101B is transported directly to the direct expansion indoor unit 108 by the refrigerant. Therefore, the indirect indoor units 104Ba-104Bd have a larger heat loss than the direct expansion indoor unit 108, and an imbalance occurs between the amount of heat exchanged in the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd connected to the indirect indoor units 104Ba-104Bd and the amount of heat exchanged in the indoor heat exchanger 82 of the direct expansion indoor unit 108. Therefore, by controlling the degree of superheat and the degree of subcooling as described above, it is possible to improve the imbalance between the amount of heat exchanged in the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd connected to the indirect indoor units 104Ba-104Bd and the amount of heat exchanged in the indoor heat exchanger 82 of the direct expansion indoor unit 108.

[0111] Furthermore, by making some of the multiple indoor units the direct expansion indoor units 108, costs can be reduced, and heat loss due to heat exchange between the refrigerant and the heat medium can be reduced, thereby improving energy conservation.

[0112] As described above, the air conditioning apparatus 100B according to the third embodiment includes an outdoor unit 101 having a compressor 11 that circulates a refrigerant in a refrigerant circuit and an outdoor heat exchanger 13 through which the refrigerant flows, a plurality of heat medium heat exchanger units 103Ba to 103Bd that have heat medium heat exchangers 32a to 32d that exchange heat between the refrigerant and a heat medium different from the refrigerant and pumps 33a to 33d that circulate the heat medium in the heat medium circuit, and indirect type indoor units 104Ba to 104Bd that have a first indoor heat exchanger through which the heat medium flows. The air conditioner is provided with a plurality of indoor units arranged in air-conditioned spaces 505-509, and a relay unit 102 interposed between the outdoor unit 101 and the plurality of heat medium heat exchanger units 103Ba-103Bd and the direct expansion type indoor unit 108, for dividing the refrigerant flowing in from the outdoor unit 101 into a plurality of flow paths and for merging the refrigerant flowing in from the plurality of heat medium heat exchanger units 103Ba-103Bd and the direct expansion type indoor unit 108. Further, the multiple heat medium heat exchanger units 103Ba-103Bd are provided corresponding to at least each of the air-conditioned spaces 505-509 in which the indirect type indoor units 104Ba-104Bd are arranged, and are connected to the indirect type indoor units 104Ba-104Bd arranged in the corresponding air-conditioned spaces 505-509, and the connected indirect type indoor units 104Ba-104Bd operate as condensers during heating operation and operate as evaporators during cooling operation.

[0113] According to the air conditioner 100B of the first embodiment, the heat medium heat exchanger units 103Ba-103Bd are provided corresponding to each of the air-conditioned spaces 505-509 in which at least the indirect type indoor units 104Ba-104Bd are arranged, and are connected to the indoor units 104a-104d arranged in the corresponding air-conditioned spaces 505-509, and the connected indoor units 104a-104d operate as condensers during heating operation and operate as evaporators during cooling operation. Therefore, even if the cooling load or the heating load is significantly biased during simultaneous cooling and heating operation, the heat medium heat exchanger units 103Ba-103Bd can be switched to operate as condensers or evaporators according to the connected indoor units 104a-104d. This allows the condenser and evaporator to operate in an appropriate ratio according to the load, thereby preventing an excessive amount of heat treatment in the heat medium heat exchangers 32a to 32d, which would result in a drop in evaporation temperature or an increase in condensation temperature, and thereby preventing a decrease in energy savings and comfort.

[0114] Furthermore, in the air conditioning apparatus 100B according to embodiment 3, when the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd and the second indoor heat exchanger of the direct expansion indoor unit 108 operate as evaporators, the degree of superheat of the second indoor heat exchanger is controlled to be greater than the degree of superheat of the heat medium heat exchangers 32a-32d, and when the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd and the second indoor heat exchanger of the direct expansion indoor unit 108 operate as condensers, the degree of subcooling of the second indoor heat exchanger is controlled to be greater than the degree of subcooling of the heat medium heat exchanger.

[0115] According to the air conditioning apparatus 100B of embodiment 3, by controlling the degree of superheat and the degree of subcooling in this manner, it is possible to improve the imbalance between the heat exchange amount in the heat medium heat exchangers 32a-32d of the heat medium heat exchanger units 103Ba-103Bd connected to the indirect indoor units 104Ba-104Bd and the heat exchange amount in the second indoor heat exchanger of the direct expansion indoor unit 108.

[0116] In addition, in the air conditioning apparatus 100B according to embodiment 3, the value obtained by dividing the rated capacity of the indirect type indoor units 104Ba-104Bd, which have the highest rated capacity, by its rated air volume is smaller than the value obtained by dividing the rated capacity of the direct expansion type indoor unit 108, which has the smallest rated capacity, by its rated air volume.

[0117] According to the air conditioner 100B pertaining to the third embodiment, by doing so, the performance of the indirect type indoor units 104Ba-104Bd becomes higher than the performance of the direct expansion type indoor unit 108. Therefore, it is possible to reduce the performance difference between the indirect type indoor units 104Ba-104Bd and the direct expansion type indoor unit 108, and eliminate the gap in temperature difference ΔT between the air temperature and refrigerant temperature in the air-conditioned spaces 505-509 that occurs between them. [Explanation of symbols]

[0118] REFERENCE SIGNS LIST 1 outdoor unit, 11 compressor, 12, 12a, 12b flow path switching valve, 13, 13a, 13b outdoor heat exchanger, 14 outdoor fan, 15, 15a, 15b flow control valve, 16a to 16d check valve, 17 accumulator, 18 outdoor control device, 19 discharge pressure sensor, 21 refrigerant heat exchanger, 22 flow control valve, 23 refrigerant heat exchanger, 24 flow control valve, 25, 25a to 25e cooling check valve, 26, 26a to 26e heating check valve, 27, 27a to 27e cooling solenoid valve, 28, 28a to 28e heating solenoid valve, 29, 29a to 29e control device, 31a to 31e flow control valve, 32a to 32e heat medium heat exchanger, 33a to 33e Pump, 34a to 34e Heat medium control device, 41a to 41e Indoor heat exchanger, 42a to 42e Indoor fan, 43a to 43e Indoor control device, 81 Flow control valve, 82 Indoor heat exchanger, 83 Indoor fan, 84 Indoor control device, 85 Gas side temperature sensor, 86 Liquid side temperature sensor, 91a to 91d Gas side temperature sensor, 92a to 92d Liquid side temperature sensor, 100, 100A, 100B Air conditioner, 101, 101A, 101B Outdoor unit, 102, 102A Relay unit, 103, 103Ba to 103Bd, 103a to 103e Heat medium heat exchanger unit, 104 Indoor unit, 104Ba to 104Bd Indirect type indoor unit, 104a to 104e Indoor unit, 105a to 105e Main refrigerant piping, 106a-106e refrigerant branch piping, 107a-107e heat medium piping, 108 direct expansion type indoor unit, 500 building, 501-504 non-air-conditioned spaces, 505-509 air-conditioned spaces.

Claims

1. an outdoor unit having a compressor that circulates a refrigerant in a refrigerant circuit and an outdoor heat exchanger through which the refrigerant flows; a plurality of heat medium heat exchanger units each including a heat medium heat exchanger for exchanging heat between the refrigerant and a heat medium different from the refrigerant, and a pump for circulating the heat medium in a heat medium circuit; a plurality of indoor units arranged in an air-conditioned space, the indoor units including an indirect type indoor unit having a first indoor heat exchanger through which the heat medium flows and a direct expansion type indoor unit having a second indoor heat exchanger through which the refrigerant flows; a relay unit that is interposed between the outdoor unit and the plurality of heat medium heat exchanger units and the direct expansion type indoor unit, and that divides the refrigerant that flows in from the outdoor unit into a plurality of flow paths and merges the refrigerant that flows in from the plurality of heat medium heat exchanger units and the direct expansion type indoor unit, The plurality of heat medium heat exchanger units include At least one indirect type indoor unit is provided for each of the air-conditioned spaces in which the indirect type indoor units are arranged, connected to the indirect type indoor unit arranged in the corresponding air-conditioned space, The indirect type indoor unit connected to the indirect type indoor unit operates as a condenser during heating operation and as an evaporator during cooling operation, The value obtained by dividing the rated capacity of the indirect type indoor unit having the largest rated capacity by its rated air volume is smaller than the value obtained by dividing the rated capacity of the direct expansion type indoor unit having the smallest rated capacity by its rated air volume. Air conditioning units.

2. When the heat medium heat exchanger of the heat medium heat exchanger unit and the second indoor heat exchanger of the direct expansion indoor unit are operated as evaporators, the degree of superheat of the second indoor heat exchanger is controlled to be greater than the degree of superheat of the heat medium heat exchanger, When the heat medium heat exchanger of the heat medium heat exchanger unit and the second indoor heat exchanger of the direct expansion indoor unit are operated as condensers, the degree of subcooling of the second indoor heat exchanger is controlled to be larger than the degree of subcooling of the heat medium heat exchanger. The air conditioning apparatus according to claim 1.

3. The plurality of heat medium heat exchanger units are disposed in a non-air-conditioned space.

3. An air conditioning apparatus according to claim 1 or 2.

4. The outdoor unit and the relay unit are connected by three main refrigerant pipes through which the refrigerant flows. The air conditioning apparatus according to any one of claims 1 to 3.

5. The three main refrigerant pipes are a high pressure gas pipe, a low pressure gas pipe, and a liquid pipe. The air conditioning apparatus according to claim 4.

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