JP7660709B2 - Air Conditioning Equipment - Google Patents

Description

This disclosure relates to air conditioning devices that are applied, for example, to multi-air conditioners for buildings.

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, making it possible to perform simultaneous cooling and heating operations with a mixture of indoor units performing cooling operation and indoor units performing heating operation.

International Publication No. 2020/197044

In the air conditioning system described in Patent Document 1, 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 heating load is heavily biased towards 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 reduced energy saving and comfort.

This disclosure has been made to solve the above problems, and aims to provide an air conditioning system that can reduce the deterioration of energy efficiency and comfort when operating both heating and cooling simultaneously.

The air-conditioning apparatus according to the present disclosure includes 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, 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 is interposed between the outdoor unit, the plurality of heat medium heat exchanger units, and the direct expansion type indoor unit, and divides the refrigerant flowing in from the outdoor unit into a plurality of flow paths, and a relay unit that merges the refrigerant flowing in from the plurality of heat medium heat exchanger units and the direct expansion indoor units, wherein the plurality of heat medium heat exchanger units are provided corresponding to at least each of the air-conditioned spaces in which an indirect type indoor unit is arranged and are connected to the indirect type indoor unit arranged in the corresponding air-conditioned space, the connected indirect type indoor unit operates as a condenser during heating operation and as an evaporator during cooling operation , and a 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 a value obtained by dividing the rated capacity of the direct expansion indoor unit having the smallest rated capacity by its rated air volume .

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 toward one side 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 a deterioration in energy saving and comfort.

1 is a schematic configuration diagram of an air conditioning apparatus according to a first embodiment. 1 is a circuit diagram of an air conditioning apparatus according to a first embodiment. FIG. 4 is a schematic configuration diagram of a modified example of the air conditioning apparatus according to the first embodiment. 4 is a diagram showing a flow of refrigerant during cooling operation of the air conditioning apparatus according to the first embodiment. FIG. 4 is a diagram showing a flow of refrigerant during heating operation of the air conditioning apparatus according to the first embodiment. FIG. 4 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high cooling ratio in the air conditioning apparatus according to the first embodiment. FIG. 4 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in the air conditioning apparatus according to the first embodiment. FIG. FIG. 7 is a circuit diagram of an air conditioning apparatus according to a second embodiment. FIG. 11 is a diagram showing the flow of refrigerant during cooling operation of an air-conditioning apparatus according to a second embodiment. FIG. 11 is a diagram showing a flow of refrigerant during heating operation of an air-conditioning apparatus according to embodiment 2. 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. 11 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in an air conditioning apparatus according to embodiment 2. FIG. FIG. 11 is a schematic configuration diagram of an air conditioning device according to a third embodiment. FIG. 11 is a circuit diagram of an air conditioning apparatus according to a third embodiment.

The following describes the embodiments with reference to the drawings. In each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is the same throughout the entire specification. The forms of the components shown in the entire specification are merely examples and are not limited to these descriptions. Furthermore, the size relationships between the components in the drawings may differ from the actual ones.

Embodiment 1.
FIG. 1 is a schematic configuration diagram of an air conditioning device 100 according to embodiment 1. The air conditioning device 100 according to embodiment 1 is installed in a building 500, such as a building, and conditions a plurality of air-conditioned spaces 505-509 within the building 500. As shown in FIG. 1, the building 500 in which the air conditioning device 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, a machine room. The air-conditioned space 505 is, for example, a large living room. The air-conditioned spaces 506-509 are, for example, small living rooms.

The air conditioning device 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 the refrigerant into multiple 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 air-conditioned space 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 conditioning device 100 includes one outdoor unit 101, one relay unit 102, five indoor units 104 (indoor units 104a to 104e in FIG. 2 described later), and five heat medium heat exchanger units 103 (heat medium heat exchanger units 103a to 103e in FIG. 2 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 heat medium heat exchanger unit 103 may be provided for a plurality of indoor units 104 .

Figure 2 is a circuit diagram of the air conditioning device 100 according to the first embodiment. As shown in Figure 2, the outdoor unit 101 and the relay unit 102 are connected by the main refrigerant pipes 105a and 105b through which the refrigerant flows. Here, the main refrigerant pipe 105a is a high-pressure pipe through which a high-pressure refrigerant flows, and the main refrigerant 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 the refrigerant branch pipes 106a to 106e through which the refrigerant flows. The heat medium heat exchanger units 103a to 103e and the indoor units 104a to 104e are connected by the heat medium pipes 107a to 107e through which the heat medium flows. Each heat medium heat exchanger unit 103a to 103e is connected in parallel with the relay unit 102. Each indoor unit 104a to 104e is connected in series with each heat medium heat exchanger unit 103a to 103e. The heat generated in the outdoor unit 101 is transported to the heat medium heat exchanger units 103a to 103e via the relay unit 102 by the refrigerant flowing through the main refrigerant pipes 105a and 105b. The heat converted in the heat medium heat exchanger units 103a to 103e is transported to the indoor units 104a to 104e by the heat medium flowing through the heat medium pipes 107a to 107e. In other words, the indoor units 104a to 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 to 103e are installed in non-air-conditioned spaces 501 and 502, which are different locations from the air-conditioned spaces 505 to 509 in which the indoor units 104a to 104e are installed. This is because the heat medium heat exchanger units 103a to 103e through which the refrigerant flows are disposed in locations different from the air-conditioned spaces 505 to 509, thereby preventing the refrigerant from leaking into the air-conditioned spaces 505 to 509.

The refrigerant used in the air conditioner 100 is, for example, a single refrigerant such as R32, a pseudo-azeotropic refrigerant mixture 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.

Figure 3 is a schematic diagram of a modified example of the air conditioning device 100 according to the first embodiment. The number of relay units 102, indoor units 104, and heat medium heat exchanger units 103 is not limited to the above. The number of heat medium heat exchanger units 103 may be equal to or greater than the number of air-conditioned spaces 505-509, and equal to or less than the number of 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 device 100 may be configured as shown in Figure 3, for example. In the modified example of the first embodiment, one outdoor unit 101 is provided, and two relay units 102 are provided. In addition, 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 that 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.

As shown in Figure 2, the air conditioning device 100 has 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 the outdoor unit 101, heat medium heat exchanger units 103a-103e, and relay unit 102 via refrigerant main pipes 105a, 105b and refrigerant branch pipes 106a-106e. The heat medium circuit is configured by connecting the heat medium heat exchanger units 103a-103e and indoor units 104a-104e via heat medium pipes 107a-107e.

The outdoor unit 101 comprises 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, and an outdoor control device 18.

The compressor 11 draws in low-temperature, low-pressure gas refrigerant, compresses it, and discharges high-temperature, high-pressure gas refrigerant. The compressor 11 circulates the refrigerant in the refrigerant circuit. The compressor 11 is, for example, an inverter-type compressor whose capacity can be controlled.

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 Figure 2 during cooling operation, and switches to the flow path shown by the dashed line in Figure 2 during heating operation. The flow path switching valve 12 may be a combination of a three-way valve or a two-way valve.

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 also operates as an evaporator during heating operation, evaporating and gasifying the refrigerant.

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, thereby controlling the condensation capacity or evaporation capacity of the outdoor heat exchanger 13.

The flow control valve 15 reduces the pressure of the refrigerant to expand it. The flow control valve 15 is, for example, an electronic expansion valve that can adjust the aperture, 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.

The check valves 16a to 16d allow the refrigerant to flow only in a specified 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.

The accumulator 17 is provided on the suction side of the compressor 11 and has the function of separating liquid refrigerant and gas refrigerant and the function of storing excess refrigerant.

The outdoor control device 18 controls the operation 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 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. 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) that detects the refrigerant pressure and a temperature sensor (not shown) that detects the refrigerant temperature or the outdoor air temperature mounted on the outdoor unit 101. The temperature sensor is, for example, a thermistor. The outdoor control device 18 can perform data communication between the heat medium control devices 34a to 34e mounted on the heat medium heat exchanger units 103a to 103e, the indoor control devices 43a to 43e mounted on the indoor units 104a to 104e, and the control device 29 mounted on the repeater 102.

The relay unit 102 includes a refrigerant-to-refrigerant heat exchanger 21, a flow control valve 22, a refrigerant-to-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 refrigerant-to-refrigerant heat exchangers 21, 23 are, for example, double-tube, plate, or shell-and-tube heat exchangers. The refrigerant-to-refrigerant heat exchangers 21, 23 exchange heat between refrigerants. The flow rate control valves 22, 24 are solenoid valves whose opening is variably controlled. The flow rate control valve 22 is connected in series with the refrigerant-to-refrigerant heat exchanger 21 and adjusts the flow rate of the heat medium flowing through the refrigerant-to-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 downstream of the cooling solenoid valves 27a to 27e via the refrigerant-to-refrigerant heat exchanger 23 and the refrigerant-to-refrigerant heat exchanger 21.

The cooling check valves 25a to 25e and the heating check valves 26a to 26e allow the flow of refrigerant only in a specified direction. The cooling check valves 25a to 25d allow the refrigerant flowing into the heat medium heat exchanger units 103a to 103e 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 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, allowing or not allowing 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.

The control device 29 controls the operation of the flow 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.

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

The flow rate control valves 31a to 31e are electronic expansion valves whose opening degree is variably controlled. The flow rate control valves 31a to 31e are connected in series with 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.

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. This transfers heat stored in the refrigerant supplied from the outdoor unit 101 to the heat medium. The heat medium heat exchangers 32a to 32e operate as condensers during heating operation, condensing and liquefying the refrigerant. The heat medium heat exchangers 32a to 32e operate as evaporators during cooling operation, evaporating and gasifying the refrigerant.

Pumps 33a to 33e are, for example, inverter-type centrifugal pumps whose capacity can be controlled. Pumps 33a to 33e have motors driven by inverters, 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, pumps 33a to 33e are arranged so that the refrigerant flow and the heat medium flow are opposed to each other during heating operation, forming a heating counterflow, but they may also be arranged so that the refrigerant flow and the heat medium flow are opposed to each other during cooling operation, forming a cooling counterflow.

The heat medium control devices 34a to 34e control the operation of the flow rate control valves 31a to 31e and the pumps 33a to 33e. The heat medium control devices 34a to 34e 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 as dedicated hardware such as an ASIC or FPGA, or both.

The indoor units 104a to 104e supply the 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 are equipped with indoor heat exchangers 41a to 41e, indoor fans 42a to 42e, and indoor control devices 43a to 43e.

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 the heat medium.

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

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 as dedicated hardware such as an ASIC or FPGA, or both.

The air conditioning apparatus 100 according to the first embodiment performs cooling or heating operation based on instructions from a remote control (not shown) or the like for the indoor units 104a to 104e. Cooling and heating operations are achieved by switching the flow path switching valve 12 of the outdoor unit 101. The air conditioning apparatus 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.

Figure 4 is a diagram showing the flow of refrigerant during cooling operation of the air conditioning apparatus 100 according to embodiment 1. The solid arrows in Figure 4 and Figures 5 to 7 described below indicate the flow of refrigerant during cooling operation, and the dashed arrows indicate the flow of refrigerant during heating operation. The flow of refrigerant during each operation is explained below.

In cooling operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows through the flow switching valve 12 into the outdoor heat exchanger 13. The refrigerant that flows into the outdoor heat exchanger 13 exchanges heat with the 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 exchanger 13 flows into the relay unit 102 through the flow control valve 15, the check valve 16a, and the main refrigerant pipe 105a.

The low-temperature, high-pressure liquid refrigerant that flows into the relay unit 102 is further cooled by heat exchange with the refrigerant in the refrigerant-to-refrigerant heat exchangers 21 and 23. After that, part of the low-temperature, high-pressure liquid refrigerant is bypassed, and the majority flows through the cooling check valves 25a to 25e and the refrigerant branch pipes 106a to 106e into the heat medium heat exchanger units 103a to 103e. Meanwhile, the bypassed low-temperature, high-pressure liquid refrigerant is depressurized 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-to-refrigerant heat exchangers 23 and 21 to evaporate and become a high-temperature, low-pressure gas refrigerant.

The low-temperature, high-pressure liquid refrigerant that flows into the heat medium heat exchanger units 103a to 103e is depressurized by the flow control valves 31a to 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 to 32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a to 32e that operate as evaporators, evaporating and becoming a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that flows out of the heat medium heat exchangers 32a to 32e passes through the refrigerant branch pipes 106a to 106e and the cooling solenoid valves 27a to 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.

The high-temperature, low-pressure gas refrigerant that flows 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.

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

The high-temperature, high-pressure gas refrigerant that flows into the heat medium heat exchanger units 103a to 103e flows into the heat medium heat exchangers 32a to 32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a to 32e that operate as condensers, condensing and liquefying it to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat medium heat exchangers 32a to 32e is depressurized by the flow control valves 31a to 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 piping 106a to 106e, the heating check valves 26a to 26e, the refrigerant-to-refrigerant heat exchangers 23, the flow control valve 24, the refrigerant-to-refrigerant heat exchangers 23, the refrigerant-to-refrigerant heat exchangers 21, and the main refrigerant piping 105b.

The low-temperature, low-pressure two-phase refrigerant that flows into the outdoor unit 101 flows through the check valve 16d and the flow rate control valve 15 into the outdoor heat exchanger 13. The refrigerant that flows into the outdoor heat exchanger 13 exchanges heat with the 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 flows out of the outdoor heat exchanger 13 flows through the flow path switching valve 12 and the accumulator 17, and returns to the compressor 11.

Figure 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, the heat medium heat exchanger unit 103 (heat medium heat exchanger units 103b to 103e in Figure 6) connected to the indoor unit 104 in cooling operation (indoor units 104b to 104e in Figure 6) operates as an evaporator, and the heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103a in Figure 6) connected to the indoor unit 104 in heating operation (indoor unit 104a in Figure 6) operates as a condenser.

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

The medium-temperature, high-pressure two-phase refrigerant that flows into the relay 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 depressurized by the flow control valve 31a to become a low-temperature, medium-pressure liquid or two-phase refrigerant, and then passes through the refrigerant branch piping 106a and the heating check valve 26a to merge with the liquid-rich refrigerant that flows out of the flow control valve 22.

The liquid-rich refrigerant is cooled and condensed in the refrigerant-to-refrigerant heat exchanger 21 to become a low-temperature, high-pressure liquid. The low-temperature, high-pressure liquid is depressurized in the flow control valve 22 to become 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. The low-temperature, medium-pressure liquid or two-phase refrigerant is then cooled and condensed in the refrigerant-to-refrigerant heat exchanger 23 to become a low-temperature, medium-pressure liquid refrigerant.

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 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 becoming a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that flows 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.

The high-temperature, low-pressure gas refrigerant that flows 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.

Figure 7 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high heating ratio in the air conditioning apparatus 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, the heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103e in Figure 7) connected to the indoor unit 104 in cooling operation (indoor unit 104e in Figure 7) operates as an evaporator, and the heat medium heat exchanger unit 103 (heat medium heat exchanger units 103a to 103d in Figure 7) connected to the indoor unit 104 in heating operation (indoor units 104a to 104d in Figure 7) operates as a condenser.

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

The high-temperature, high-pressure gas refrigerant that flows into the heat medium heat exchanger units 103a to 103d flows into the heat medium heat exchangers 32a to 32d, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a to 32d that operate as condensers, condensing and liquefying it, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat medium heat exchangers 32a to 32d is depressurized by the flow control valves 31a to 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 to 106d and the heating check valves 26a to 26d, is cooled in the refrigerant-to-refrigerant heat exchanger 23, condenses and liquefies it, becoming 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 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.

Meanwhile, the bypassed low-temperature medium-pressure liquid refrigerant flows into the heat medium heat exchanger unit 103e through the cooling check valve 25e and the refrigerant branch pipe 106e. The low-temperature medium-pressure liquid refrigerant that flows into the heat medium heat exchanger unit 103e is depressurized by the flow 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, evaporating and vaporizing, becoming 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.

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.

The low-temperature, low-pressure, two-phase refrigerant that flows into the outdoor unit 101 flows through the check valve 16d and the flow rate control valve 15 into the outdoor heat exchanger 13. The refrigerant that flows into the outdoor heat exchanger 13 exchanges heat with the 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 flows out of the outdoor heat exchanger 13 flows through the flow path switching valve 12 and the accumulator 17 and returns to the compressor 11.

As described above, the air conditioning apparatus 100 according to the first embodiment comprises 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 to 103e having heat medium heat exchangers 32a to 32e that exchange heat between the refrigerant and a heat medium different from the refrigerant and pumps 33a to 33e that circulate the heat medium in the heat medium circuit, a plurality of indoor units 104a to 104e having indoor heat exchangers 41a to 41e through which the heat medium flows and arranged in the air-conditioned spaces 505 to 509, and a relay unit 102 that is interposed between the outdoor unit 101 and the plurality of heat medium heat exchanger units 103a to 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 to 103e. In addition, the multiple heat medium heat exchanger units 103a to 103e are provided corresponding to at least each of the air-conditioned spaces 505 to 509 in which the indoor units 104a to 104e are arranged, and are connected to the indoor units 104a to 104e arranged in the corresponding air-conditioned spaces 505 to 509, so that the connected indoor units 104a to 104e function as condensers during heating operation and as evaporators during cooling operation.

According to the air conditioning device 100 of the first embodiment, the heat medium heat exchanger units 103a to 103e are provided in correspondence with at least each of the air-conditioned spaces 505 to 509 in which the indoor units 104a to 104e are arranged, and are connected to the indoor units 104a to 104e arranged in the corresponding air-conditioned spaces 505 to 509, and the connected indoor units 104a to 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 to 103e can be switched to operate as condensers or evaporators according to the connected indoor units 104a to 104e. By doing so, the condenser and evaporator can be operated in an appropriate ratio according to the load, so that the amount of heat processed in the heat medium heat exchangers 32a to 32e is prevented from becoming excessive, which would result in a drop in the evaporation temperature or an increase in the condensation temperature, thereby preventing a deterioration in energy savings and comfort.

In addition, since the indoor unit 104 is configured so that no refrigerant flows through it, leakage of refrigerant from the indoor unit 104 can be prevented.

In addition, in the air conditioning apparatus 100 relating to embodiment 1, multiple heat medium heat exchanger units 103a to 103e are arranged in non-conditioned spaces 501 to 504.

According to the air conditioning apparatus 100 of embodiment 1, the heat medium heat exchanger units 103a to 103e are arranged in the non-air-conditioned spaces 501 to 504, thereby preventing refrigerant leakage from the heat medium heat exchanger units 103a to 103e to the air-conditioned spaces 505 to 509.

In addition, in the air conditioning apparatus 100 according to embodiment 1, the multiple heat medium heat exchanger units 103a to 103e are arranged to be paired with the indoor units 104a to 104e.

According to the air conditioning device 100 of the first embodiment, since the heat medium heat exchanger units 103a to 103e are provided in pairs with the indoor units 104a to 104e, the condenser and the evaporator can be operated in a more appropriate ratio according to the load. As a result, the amount of heat treatment in the heat medium heat exchangers 32a to 32e is excessive, and the drop in the evaporation temperature or the rise in the condensation temperature is further suppressed, so that the deterioration of energy saving and comfort can be further suppressed.

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.

In the second embodiment, the configurations of the outdoor unit 101A and the relay unit 102A are different from those in the first embodiment. In the second embodiment, the configuration of the refrigerant piping connecting the outdoor unit 101A and the relay unit 102A is also different from that in the first embodiment.

Figure 8 is a circuit diagram of the air conditioning device 100A according to embodiment 2. As shown in Figure 8, the outdoor unit 101A and the relay unit 102A are connected by the refrigerant main pipes 105c to 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 to 103e are connected by the refrigerant branch pipes 106a to 106e through which the refrigerant flows. The heat medium heat exchanger units 103a to 103e and the indoor units 104a to 104e are connected by the heat medium pipes 107a to 107e through which the heat medium flows. Each heat medium heat exchanger unit 103a to 103e is connected in parallel with the relay unit 102A. Each of the indoor units 104a to 104e is connected in series with each of the heat medium heat exchanger units 103a to 103e. The heat generated in the outdoor unit 101A is transported to the heat medium heat exchanger units 103a to 103e via the relay unit 102A by the refrigerant flowing through the refrigerant main pipes 105c to 105e. The heat converted in the heat medium heat exchanger units 103a to 103e is transported to the indoor units 104a to 104e by the heat medium flowing through the heat medium pipes 107a to 107e. In other words, the indoor units 104a to 104e cool or heat the air-conditioned spaces 505 to 509 by the heat medium to which heat is transferred from the refrigerant supplied from the outdoor unit 101A.

The outdoor unit 101A includes a compressor 11, flow 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-to-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 a description thereof will be omitted.

Figure 9 is a diagram showing the flow of refrigerant during cooling operation of the air conditioning apparatus 100A according to embodiment 2. The solid arrows in Figure 9 and Figures 10 to 12 described below indicate the flow of refrigerant during cooling operation, and the dashed arrows indicate the flow of refrigerant during heating operation. The flow of refrigerant during each operation is explained below.

In cooling operation, part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows through the flow switching valve 12a into the outdoor heat exchanger 13a, and the rest flows through the flow switching valve 12b into the outdoor heat exchanger 13b. The refrigerant that flows into the outdoor heat exchangers 13a and 13b exchanges heat with the 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 passes through the flow control valves 15a and 15b, respectively, and then merges, and flows through the main refrigerant pipe 105e into the relay unit 102A.

The low-temperature, high-pressure liquid refrigerant that flows into the relay unit 102A exchanges heat with the refrigerant in the refrigerant-to-refrigerant heat exchanger 23, condenses, and is further cooled. After that, part 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 into the heat medium heat exchanger units 103a-103e. Meanwhile, the bypassed low-temperature, high-pressure liquid refrigerant is depressurized 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-to-refrigerant heat exchanger 23, evaporating and becoming a high-temperature, low-pressure gas refrigerant.

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

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

Figure 10 is a diagram showing the flow of refrigerant during heating operation of the air conditioning apparatus 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 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 to 27e, merges with the remaining gas refrigerant that has passed through the heating solenoid valves 28a to 28e in the refrigerant branch pipes 106a to 106e, and then flows into the heat medium heat exchanger units 103a to 103e.

The high-temperature, high-pressure gas refrigerant that flows into the heat medium heat exchanger units 103a to 103e flows into the heat medium heat exchangers 32a to 32e, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a to 32e that operate as condensers, condensing and liquefying it to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat medium heat exchangers 32a to 32e is depressurized by the flow control valves 31a to 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 to 106e, the heating check valves 26a to 26e, and the main refrigerant pipe 105e.

A portion of the low-temperature, low-pressure two-phase refrigerant that flows 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 flows 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 flows out of the outdoor heat exchangers 13a and 13b pass through the flow switching valves 12a and 12b, respectively, and then merge, and pass through the accumulator 17 and return to the compressor 11 again.

Figure 11 is a diagram showing the flow of refrigerant during simultaneous cooling and heating operation with a high cooling ratio in the air conditioning apparatus 100A according to embodiment 2. In simultaneous cooling and heating operation with a high cooling ratio, the heat medium heat exchanger unit 103 (heat medium heat exchanger units 103b to 103e in Figure 10) connected to the indoor unit 104 (indoor units 104b to 104e in Figure 10) operating in cooling mode operates as an evaporator, and the heat medium heat exchanger unit 103 (heat medium heat exchanger unit 103a in Figure 10) connected to the indoor unit 104 (indoor unit 104a in Figure 10) operating in heating mode operates as a condenser.

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 main refrigerant 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 control valve 31a.

On the other hand, the refrigerant that flows into the outdoor heat exchanger 13a exchanges heat with the air supplied by the outdoor fan 14, and a portion of it condenses and liquefies, becoming 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 merges 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, condenses and liquefies, becoming a low-temperature, medium-pressure liquid refrigerant. A portion 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.

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

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

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

In simultaneous cooling and heating operation with a high heating ratio, the 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 flows into the relay unit 102A flows into the heat medium heat exchanger units 103a to 103d through the heating solenoid valves 28a to 28d and the refrigerant branch pipes 106a to 106d.

The high-temperature, high-pressure gas refrigerant that flows into the heat medium heat exchanger units 103a to 103d flows into the heat medium heat exchangers 32a to 32d, where it exchanges heat with the heat medium in the heat medium heat exchangers 32a to 32d that operate as condensers, condensing and liquefying it to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat medium heat exchangers 32a to 32d is reduced in pressure by the flow control valves 31a to 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 to 106d and the heating check valves 26a to 26d. The low-temperature, medium-pressure liquid or two-phase refrigerant that passes through the heating check valves 26a to 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 has flowed 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.

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 depressurized by the flow 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, evaporating and vaporizing, becoming 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.

Then, after passing through the flow path switching valve 12b, the high-temperature, low-pressure gas or two-phase refrigerant 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.

As described above, in the air conditioning apparatus 100A according to the second embodiment, the outdoor unit 101A and the relay unit 102A are connected by 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.

According to the air conditioning apparatus 100A of 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.

In this way, the relay unit 102A can be configured to include a refrigerant heat exchanger 23, a flow rate control valve 24, a cooling check valve 25, a heating check valve 26, a cooling solenoid valve 27, a heating solenoid valve 28, and a 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, and the installation space can be secured and the degree of freedom of installation can be improved.

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 parts that are the same as or equivalent to the first and second embodiments will be given the same reference numerals.

Embodiment 3 differs from embodiments 1 and 2 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 indirect type indoor units), 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 direct expansion type indoor units).

Figure 13 is a schematic diagram of an air conditioning device 100B according to embodiment 3. Figure 14 is a circuit diagram of an air conditioning device 100B according to embodiment 3. As shown in Figures 13 and 14, the air conditioning device 100B includes an outdoor unit 101B, an indoor unit, heat medium heat exchanger units 103Ba to 103Bd, and a relay unit 102. In embodiment 3, 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 to 509. In addition, the heat medium heat exchanger units 103Ba to 103Bd are provided to be paired with the indoor units (indirect indoor units 104Ba to 104Bd) provided in the air-conditioned spaces 505 and 507 to 509, but the heat medium heat exchanger unit 103 is not provided for the indoor unit (direct expansion indoor unit 108) provided in the air-conditioned space 506. In other words, 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.

The outdoor unit 101 includes a compressor 11, a flow 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 inlet of the refrigerant side 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 outlet of the refrigerant side of the heat medium heat exchangers 32a to 32d during heating operation.

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 embodiment 1, so the description will be omitted.

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

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

Indirect indoor unit ratio ≦ (A _{total area} - _{A direct expansion} ) / A _{total area} ... (1)
A _{total area} : the total floor area of the air-conditioned space in which all indoor units are installed [m ² ], A _{direct expansion} : the maximum floor area in the air-conditioned space in which a direct expansion type indoor unit is installed that does not exceed the lower flammability limit (LFL) even if the refrigerant leaks [m ² ]

A _{total area} = Q _cooling / q (2)
Q _cooling : cooling capacity of the air conditioner [kW], q: unit heat load (0.128 kW/ ^m2 *Assumed value for an office)

A _{direct expansion} = M/(h×LFL)...(3)
M: amount of refrigerant (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 ]

In addition, the indirect indoor unit ratio was calculated using formulas (1) to (3) based on the conditions listed in Tables 1 to 4 below.

Table 1 shows an example of a trial calculation of the indirect type indoor unit ratio assuming a cooling capacity of 56 kW.

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

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

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

As described above, if the indirect indoor unit ratio is 73% or less, the required cooling capacity can be achieved under any of the above conditions, and the LFL will not be exceeded even if the refrigerant leaks in the air-conditioned spaces 505-509 in which the direct expansion indoor units 108 are installed. Therefore, the direct expansion 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.

In addition, the value obtained by dividing the rated capacity of the indirect 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 indoor unit 108, which has the smallest rated capacity, by its rated air volume. In other words, the performance of the indirect indoor units 104Ba-104Bd is made higher than the performance of the direct expansion indoor unit 108. This reduces the performance difference between the indirect indoor units 104Ba-104Bd and the direct expansion indoor unit 108, and eliminates the gap in temperature difference ΔT between the air temperature and refrigerant temperature in the air-conditioned spaces 505-509 that occurs between them.

In addition, different control target values are set for the degree of superheat and the degree of subcooling between the heat medium heat exchanger units 103Ba to 103Bd and the direct expansion indoor unit 108. When one or more of the heat medium heat exchangers 32a to 32d of the heat medium heat exchanger units 103Ba to 103Bd connected to the indirect indoor units 104Ba to 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 greater than the degree of superheat of the heat medium heat exchangers 32a to 32d. Here, the degree of superheat of the heat medium heat exchangers 32a to 32d is calculated by (detection value of the gas side temperature sensors 91a to 91d) - (detection value of the liquid side temperature sensors 92a to 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).

In addition, when one or more of the heat medium heat exchangers 32a to 32d of the heat medium heat exchanger units 103Ba to 103Bd connected to the indirect indoor units 104Ba to 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 to 32d. Here, the degree of subcooling of the heat medium heat exchangers 32a to 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 to 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).

Here, in the indirect indoor units 104Ba to 104Bd, the heat generated in the outdoor unit 101B is transported by the refrigerant to the heat medium heat exchanger units 103Ba to 103Bd, where it is transferred from the refrigerant to the heat medium, and then transported by the heat medium to the indirect indoor units 104Ba to 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 to 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 to 32d of the heat medium heat exchanger units 103Ba to 103Bd connected to the indirect indoor units 104Ba to 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 to 32d of the heat medium heat exchanger units 103Ba to 103Bd connected to the indirect indoor units 104Ba to 104Bd and the amount of heat exchanged in the indoor heat exchanger 82 of the direct expansion indoor unit 108.

In addition, by making some of the multiple indoor units direct expansion type 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 savings.

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 having 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 indoor units 104Ba to 104Bd having a first indoor heat exchanger through which the heat medium flows. The air conditioner includes a plurality of indoor units arranged in the air-conditioned spaces 505-509, and a direct expansion type indoor unit 108 having a second indoor heat exchanger through which a refrigerant flows. The air conditioner is also provided with a relay unit 102 that is 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 and that divides the refrigerant flowing in from the outdoor unit 101 into a plurality of flow paths and merges the refrigerant flowing in from the plurality of heat medium heat exchanger units 103Ba-103Bd and the direct expansion type indoor unit 108. In addition, the multiple heat medium heat exchanger units 103Ba to 103Bd are provided corresponding to at least each of the air-conditioned spaces 505 to 509 in which the indirect type indoor units 104Ba to 104Bd are arranged, and are connected to the indirect type indoor units 104Ba to 104Bd arranged in the corresponding air-conditioned spaces 505 to 509, and the connected indirect type indoor units 104Ba to 104Bd operate as condensers during heating operation and operate as evaporators during cooling operation.

According to the air conditioning device 100B of the first embodiment, the heat medium heat exchanger units 103Ba to 103Bd are provided in correspondence with at least each of the air-conditioned spaces 505 to 509 in which the indirect indoor units 104Ba to 104Bd are arranged, and are connected to the indoor units 104a to 104d arranged in the corresponding air-conditioned spaces 505 to 509, and the connected indoor units 104a to 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 to 103Bd can be switched to operate as condensers or evaporators according to the connected indoor units 104a to 104d. This allows the condenser and evaporator to operate in an appropriate ratio according to the load, thereby preventing an excessive amount of heat processing 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 deterioration in energy savings and comfort.

In addition, in the air conditioning apparatus 100B according to embodiment 3, when the heat medium heat exchangers 32a to 32d of the heat medium heat exchanger units 103Ba to 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 to 32d, and when the heat medium heat exchangers 32a to 32d of the heat medium heat exchanger units 103Ba to 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.

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

In addition, in the air conditioning apparatus 100B of embodiment 3, the value obtained by dividing the rated capacity of the indirect type indoor units 104Ba to 104Bd, which have the highest rated capacity, by their 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 lowest rated capacity, by its rated air volume.

According to the air conditioning apparatus 100B of embodiment 3, by doing so, the performance of the indirect type indoor units 104Ba to 104Bd becomes higher than the performance of the direct expansion type indoor unit 108. Therefore, the performance difference between the indirect type indoor units 104Ba to 104Bd and the direct expansion type indoor unit 108 is reduced, and the gap in temperature difference ΔT between the air temperature and the refrigerant temperature in the air-conditioned spaces 505 to 509 that occurs between them can be eliminated.

REFERENCE SIGNS LIST 1 Outdoor unit, 11 Compressor, 12, 12a, 12b Flow 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 rate adjustment 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 Refrigerant main piping, 106a to 106e refrigerant branch piping, 107a to 107e heat medium piping, 108 direct expansion type indoor unit, 500 building, 501 to 504 non-air-conditioned spaces, 505 to 509 air-conditioned spaces.

Claims (5)

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,
An air conditioning apparatus, wherein a 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 a value obtained by dividing the rated capacity of the direct expansion type indoor unit having the smallest rated capacity by its rated air volume. 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,
2. The air-conditioning apparatus according to claim 1, wherein, 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 operate as condensers, a degree of subcooling of the second indoor heat exchanger is controlled to be greater than a degree of subcooling of the heat medium heat exchanger. The air-conditioning apparatus according to claim 1 or 2 , wherein the plurality of heat medium heat exchanger units are arranged in a non-air-conditioned space. The air-conditioning apparatus according to any one of claims 1 to 3 , wherein 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 claim 4 , wherein the three main refrigerant pipes are a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe.

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