Air conditioning system

Abstract

The present disclosure provides an air conditioning system that can simultaneously control the temperature and humidity of a space to be air-conditioned using a single refrigerant system. [Solution] The air conditioning system disclosed herein comprises an outdoor unit and a plurality of indoor units connected to the outdoor unit by refrigerant piping, and the plurality of indoor units installed in the space to be air-conditioned perform latent heat and sensible heat processing operation, including a first indoor unit that processes latent heat and a second indoor unit that processes sensible heat.

Description

[Technical Field]

[0001] The present disclosure relates to air conditioning systems. [Background technology]

[0002] Patent Document 1 discloses an air conditioning system equipped with multiple air conditioners for the same room. In the air conditioning system disclosed in Patent Document 1, at least one air conditioner cools the air to a temperature below the dew point, and the other air conditioners cool the air to a temperature above the dew point. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-194291 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides an air conditioning system that can simultaneously control the temperature and humidity of a space to be air-conditioned using a single refrigerant system. [Means for solving the problem]

[0005] The air conditioning system of the present disclosure comprises an outdoor unit and a plurality of indoor units connected to the outdoor unit by refrigerant piping, and the plurality of indoor units installed in the space to be air-conditioned perform latent heat and sensible heat processing operation, including a first indoor unit that processes latent heat and a second indoor unit that processes sensible heat. [Effects of the Invention]

[0006] The air conditioning system of the present disclosure has multiple indoor units in one refrigerant system that are installed in the space to be conditioned, and operates them separately as indoor units that process latent heat and indoor units that process sensible heat, so that the temperature and humidity of the space to be conditioned can be controlled simultaneously using one refrigerant system. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows a configuration of an air conditioning system according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing the configuration of a control system of an indoor unit according to the first embodiment. [Figure 3] FIG. 1 is a diagram showing the configuration of a control system of an outdoor unit according to a first embodiment. [Figure 4] A sequence diagram showing the operation of the air conditioning system according to the first embodiment. [Figure 5] Diagram showing the state of moist air in embodiment 1 DETAILED DESCRIPTION OF THE INVENTION

[0008] (Findings that formed the basis of this disclosure) At the time the inventors arrived at the idea of ​​this disclosure, there was a technology that simultaneously controlled the temperature and humidity of a space to be air-conditioned. The technology described in Patent Document 1 has an air conditioning system equipped with multiple refrigerant systems, and each refrigerant system is divided into a refrigerant system that processes latent heat and a refrigerant system that processes sensible heat, thereby simultaneously controlling the temperature and humidity of the space to be air-conditioned. However, the inventors discovered a problem with the technology described in Patent Document 1: multiple refrigerant systems are required to process latent heat and sensible heat in the space to be air-conditioned, resulting in a complex system configuration. To solve this problem, the inventors came up with the subject matter of the present disclosure. Therefore, the present disclosure provides an air conditioning system that can simultaneously control the temperature and humidity of a space to be air-conditioned using a single refrigerant system.

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. However, in some cases, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or redundant explanation of substantially the same configuration may be omitted. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) [1-1.Configuration] [1-1-1. Air conditioning system configuration] FIG. 1 is a diagram showing the configuration of an air conditioning system 1. As shown in FIG.

[0011] An air conditioning system 1 is a system installed in facilities such as large buildings and schools. As shown in FIG. 1, the air conditioning system 1 includes an outdoor unit 2 installed outdoors and multiple indoor units 3 installed indoors. The air conditioning system 1 of this embodiment is configured such that four indoor units 3A, 3B, 3C, and 3D are each connected to one outdoor unit 2 by refrigerant piping RP. The air conditioning system 1 performs air conditioning operation using the outdoor unit 2 and the indoor units 3, and the indoor units 3 air-condition the conditioned space in which the indoor units 3 are installed. Note that this embodiment illustrates a case where each of the indoor units 3 air-conditions the same conditioned space.

[0012] The outdoor unit 2 includes a compressor 20. A gas-liquid separator 21 that supplies gas refrigerant to the compressor 20 is connected to the suction side of the compressor 20, and a four-way valve 23 is connected to the discharge side of the compressor 20 via an oil separator 22. An outdoor heat exchanger 25 that is equipped with an outdoor blower fan 24 is connected to the four-way valve 23. The outdoor heat exchanger 25 is configured to exchange heat between the refrigerant and air sent by the outdoor blower fan 24. An outdoor expansion valve 26 is connected to the outdoor heat exchanger 25.

[0013] A plurality of indoor units 3 are connected to the outdoor expansion valve 26 and the four-way valve 23 by refrigerant piping RP. Each indoor unit 3 has an indoor heat exchanger 31 equipped with an indoor blower fan 30, and an indoor expansion valve 32 is connected to one side of the indoor heat exchanger 31. Each indoor unit 3 is provided with a first refrigerant temperature sensor 33 and a third refrigerant temperature sensor 35 on both sides of the indoor heat exchanger 31. Furthermore, the indoor heat exchanger 31 is provided with a second refrigerant temperature sensor 34. These refrigerant temperature sensors will be described later.

[0014] In this embodiment, the multiple indoor units 3 perform latent heat sensible heat treatment operation during cooling. The latent heat sensible heat treatment operation is an operation in which the multiple indoor units 3 include at least a first indoor unit and a second indoor unit. The latent heat sensible heat treatment operation may also be an operation in which the multiple indoor units 3 further include a third indoor unit.

[0015] Here, the first indoor unit, the second indoor unit, and the third indoor unit will be explained. The first indoor unit is the indoor unit 3 that processes latent heat. More specifically, the first indoor unit is the indoor unit 3 that controls the opening of the indoor expansion valve 32 so that the refrigerant flowing into the indoor heat exchanger 31 is at or below the dew point temperature. The first indoor unit is also the indoor unit 3 that controls the opening of the indoor expansion valve 32 so that the refrigerant flows into the indoor heat exchanger 31 in a gas-liquid two-phase state or a liquid phase state and flows out of the indoor heat exchanger 31 in a gas-liquid two-phase state or a liquid phase state. The second indoor unit is the indoor unit 3 that processes sensible heat. The second indoor unit is the indoor unit 3 that controls the opening degree of the indoor expansion valve 32 so that the refrigerant flows into the indoor heat exchanger 31 in a gas-liquid two-phase state and flows out of the indoor heat exchanger 31 in a gas-phase state. The third indoor unit is an indoor unit 3 that processes latent heat and sensible heat. The third indoor unit is an indoor unit 3 that controls the opening of the indoor expansion valve 32 so that the refrigerant flows into the indoor heat exchanger 31 in a liquid phase and flows out of the indoor heat exchanger 31 in a gas phase.

[0016] [1-1-2. Configuration of indoor unit control system] Next, the configuration of the control system of the indoor unit 3 will be described. FIG. 2 is a diagram showing the configuration of the control system of the indoor unit 3. As shown in FIG.

[0017] The indoor unit 3 is equipped with an indoor control unit 300, an indoor communication unit 301, an indoor blower fan 30, an indoor expansion valve 32, a first refrigerant temperature sensor 33, a second refrigerant temperature sensor 34, a third refrigerant temperature sensor 35, an intake temperature sensor 302, an intake humidity sensor 303, and an outlet temperature sensor 304.

[0018] Before describing the indoor control unit 300, the indoor communication unit 301, first refrigerant temperature sensor 33, second refrigerant temperature sensor 34, third refrigerant temperature sensor 35, suction temperature sensor 302, suction humidity sensor 303, and blowout temperature sensor 304 will be described.

[0019] The indoor communication unit 301 includes communication hardware such as a communication circuit that complies with the above-mentioned communication method, and communicates with the outdoor unit 2 in accordance with the control of the indoor control unit 300.

[0020] The first refrigerant temperature sensor 33 is a sensor that detects the temperature of the refrigerant flowing into the indoor heat exchanger 31 when the indoor unit 3 is operating in cooling mode, and detects the temperature of the refrigerant flowing out of the indoor heat exchanger 31 when the indoor unit 3 is operating in heating mode. The second refrigerant temperature sensor 34 is disposed approximately in the center of the flow path through which the refrigerant flows in the indoor heat exchanger 31, and is a sensor that detects the temperature of the refrigerant flowing in the indoor heat exchanger 31. The third refrigerant temperature sensor 35 is a sensor that detects the temperature of the refrigerant flowing out of the indoor heat exchanger 31 when the indoor unit 3 is operating in cooling mode, and detects the temperature of the refrigerant flowing into the indoor heat exchanger 31 when the indoor unit 3 is operating in heating mode.

[0021] The suction temperature sensor 302 is a sensor that detects the temperature of the air drawn into the indoor unit 3 (hereinafter referred to as "suction temperature"). The intake humidity sensor 303 is a sensor that detects the relative humidity of the air that the indoor unit 3 draws in (hereinafter referred to as "intake humidity"). The blowout temperature sensor 304 is a sensor that detects the temperature of the air blown out by the indoor unit 3 (hereinafter referred to as "blowout temperature").

[0022] The indoor control unit 300 comprises an indoor processor 310, which is a processor such as a CPU (Central Processing Unit) or MPU (Micro Processor Unit), an indoor memory 320, and an interface circuit for connecting other devices and sensors. Connected to the indoor control unit 300 are an indoor communication unit 301, an indoor blower fan 30, an indoor expansion valve 32, a first refrigerant temperature sensor 33, a second refrigerant temperature sensor 34, a third refrigerant temperature sensor 35, an intake temperature sensor 302, an intake humidity sensor 303, and an outlet temperature sensor 304.

[0023] The indoor memory 320 is a storage device that stores programs and data. The indoor memory 320 stores a control program 321 and data to be processed by the indoor processor 310. The indoor memory 320 has a non-volatile storage area. The indoor memory 320 also has a volatile storage area, and constitutes a work area for the indoor processor 310. The indoor memory 320 is constituted by, for example, a read-only memory (ROM) or a random access memory (RAM).

[0024] The indoor processor 310 reads and executes a control program 321 stored in the indoor memory 320, thereby functioning as an indoor communication control unit 311, a dew-point temperature calculation unit 312, and an expansion valve control unit 313.

[0025] [1-1-2-1. Indoor communication control unit] The indoor communication control unit 311 communicates with the outdoor unit 2 via the indoor communication unit 301. The indoor communication control unit 311 transmits operation data to the outdoor unit 2.

[0026] The operating data transmitted to the outdoor unit 2 includes the intake temperature detected by the intake temperature sensor 302, the intake humidity detected by the intake humidity sensor 303, the discharge temperature detected by the discharge temperature sensor 304, and an indoor unit ID (Identification) for identifying the indoor unit 3. Furthermore, the operating data transmitted by the outdoor unit 2 includes the set temperature and set humidity set by the user using a remote control (not shown) connected to the indoor unit 3.

[0027] When the user changes the set temperature or set humidity using a remote control (not shown) connected to the indoor unit 3, the indoor communication control unit 311 generates operating data and transmits the generated operating data to the outdoor unit 2. Furthermore, when a predetermined period has passed since the indoor communication control unit 311 last transmitted operating data, the indoor communication control unit 311 generates operating data and transmits the generated operating data to the outdoor unit 2. When generating the operating data, the indoor communication control unit 311 collects detection values ​​from the intake temperature sensor 302, intake humidity sensor 303, and discharge temperature sensor 304, and generates operating data including the collected detection values.

[0028] [1-1-2-2. Dew point temperature calculation section] The dew-point temperature calculation unit 312 calculates the dew-point temperature based on the following formulas (1) to (3).

[0029] Td = 237.3 × log 10 (6.1078 / e)×log 10 (e / 6.1078)-7.5···(1) e = es × RH × 100 (2) es=6.1078×107.5t / (t+237.3)···(3) In equation (1), "Td" represents the dew point temperature. Also, in equations (1) and (2), "e" represents the water vapor pressure of the air [hPa]. Also, in equations (2) and (3), "es" represents the saturated water vapor pressure [hPa]. Also, in equation (2), "RH" represents the relative humidity [%]. Also, in equation (3), "t" represents the air temperature [℃].

[0030] Dew-point temperature calculation unit 312 substitutes the suction temperature detected by suction temperature sensor 302 into "t" in equation (3) to calculate "es." Dew-point temperature calculation unit 312 also substitutes the suction humidity detected by suction humidity sensor 303 into "RH" in equation (2), and also substitutes the saturated water vapor pressure calculated by equation (3) into "es" in equation (2) to calculate "e." Then, dew-point temperature calculation unit 312 calculates the left-hand side of equation (1) by substituting the water vapor pressure of the air calculated by equation (2) into "e" in equation (1), thereby calculating the dew-point temperature.

[0031] [1-1-2-3. Expansion valve control section] The expansion valve control section 313 controls the opening degree of the indoor expansion valve 32 based on the temperature detected by a refrigerant temperature sensor provided in the indoor unit 3. Details of the expansion valve control section 313 will be described later.

[0032] [1-1-3. Configuration of outdoor unit control system] Next, the configuration of the control system of the outdoor unit 2 will be described. FIG. 3 is a diagram showing the configuration of a control system of the outdoor unit 2. As shown in FIG.

[0033] The outdoor unit 2 includes an outdoor control unit 200, an outdoor communication unit 201, a compressor 20, a four-way valve 23, an outdoor blower fan 24, and an outdoor expansion valve 26.

[0034] Before describing the outdoor control unit 200, the outdoor communication unit 201 will be described. The outdoor communication unit 201 includes communication hardware such as a communication circuit that complies with the above-mentioned communication method, and communicates with the indoor unit 3 according to the control of the outdoor control unit 200.

[0035] The outdoor control unit 200 includes an outdoor processor 210, which is a processor such as a CPU or MPU, an outdoor memory 220, and an interface circuit for connecting other devices and sensors. The outdoor control unit 200 is connected to an outdoor communication unit 201, a compressor 20, a four-way valve 23, an outdoor blower fan 24, and an outdoor expansion valve 26.

[0036] The outdoor memory 220 is a storage device that stores programs and data. The outdoor memory 220 stores a control program 221 and data to be processed by the outdoor processor 210. The outdoor memory 220 has a non-volatile storage area. The outdoor memory 220 also has a volatile storage area, and constitutes a work area for the outdoor processor 210. The outdoor memory 220 is constituted by, for example, a ROM or a RAM.

[0037] The outdoor processor 210 reads and executes the control program 221 stored in the outdoor memory 220, thereby functioning as an outdoor communication control unit 211, an intake absolute humidity calculation unit 212, a dew point absolute humidity calculation unit 213, a target absolute humidity calculation unit 214, a sum calculation unit 215, a target dehumidification amount calculation unit 216, a ratio calculation unit 217, a selection unit 218, and an operation control unit 219.

[0038] [1-1-3-1. Outdoor communication control unit] The outdoor communication control unit 211 communicates with the indoor units 3 via the outdoor communication unit 201. The outdoor communication control unit 211 receives operation data from each indoor unit 3.

[0039] [1-1-3-2. Intake absolute humidity calculation section] The suction absolute humidity calculation unit 212 calculates the suction absolute humidity based on the following equations (4) to (6) for each piece of operating data received by the outdoor communication control unit 211. The suction absolute humidity is the absolute humidity of the air sucked into the indoor unit 3.

[0040] X = 0.621298 × f(Pf) (4) f = es × RH ÷ 100 (5) es=6.1078×107.5t / (t+237.3)···(6) In equation (4), "X" represents the intake absolute humidity. In equation (4), "P" represents atmospheric pressure [hPa]. In equations (4) and (5), "f" represents the water vapor partial pressure [hPa]. In equation (5), "RH" represents the relative humidity [%]. In equations (5) and (6), "es" represents the saturated water vapor pressure [hPa]. In equation (6), "t" represents the air temperature [℃].

[0041] The suction absolute humidity calculation unit 212 substitutes the suction temperature detected by the suction temperature sensor 302, which is included in the operating data to be processed, into "t" in equation (6) to calculate "es." The suction absolute humidity calculation unit 212 also substitutes the suction humidity detected by the suction humidity sensor 303, which is included in the operating data to be processed, into "RH" in equation (5), and also substitutes the saturated water vapor pressure calculated using equation (6) into "es" in equation (5) to calculate "f." The suction absolute humidity calculation unit 212 then substitutes the water vapor partial pressure calculated using equation (5) into "f" in equation (4), and substitutes 1013.25 into "P" in equation (4), to calculate the left side of equation (4), thereby calculating the suction absolute humidity.

[0042] [1-1-3-3. Dew point absolute humidity calculation section] The dew-point absolute humidity calculation unit 213 calculates the dew-point absolute humidity based on the above formulas (1) to (6) for each piece of operation data received by the outdoor communication control unit 211. The dew-point absolute humidity is the absolute humidity calculated from the dew-point temperature.

[0043] The dew-point absolute humidity calculation unit 213 calculates the dew-point temperature in the same manner as the dew-point temperature calculation unit 312, based on the suction temperature and suction humidity included in the operating data to be processed. Next, the dew-point absolute humidity calculation unit 213 substitutes the calculated dew-point temperature for "t" in equation (6) to calculate "es." The dew-point absolute humidity calculation unit 213 also substitutes the suction humidity included in the operating data to be processed for "RH" in equation (5), and also substitutes the saturated water vapor pressure calculated using equation (6) for "es" in equation (5) to calculate "f." The dew-point absolute humidity calculation unit 213 then substitutes the water vapor partial pressure calculated using equation (5) for "f" in equation (4), and substitutes 1013.25 for "P" in equation (4), to calculate the left-hand side of equation (4), thereby calculating the dew-point absolute humidity.

[0044] [1-1-3-4. Target absolute humidity calculation section] The target absolute humidity calculation unit 214 calculates the target absolute humidity based on the above formulas (4) to (6) for each piece of operation data received by the outdoor communication control unit 211. The target absolute humidity is a target absolute humidity, and is calculated from the set temperature and set humidity set by the user.

[0045] The target absolute humidity calculation unit 214 substitutes the set temperature included in the operating data to be processed into "t" in equation (6) to calculate "es." The target absolute humidity calculation unit 214 also substitutes the set humidity included in the operating data to be processed into "RH" in equation (5), and also substitutes the saturated water vapor pressure calculated using equation (6) into "es" in equation (5) to calculate "f." The target absolute humidity calculation unit 214 then substitutes the water vapor partial pressure calculated using equation (5) into "f" in equation (4), and substitutes 1013.25 into "P" in equation (4), to calculate the left side of equation (4), thereby calculating the target absolute humidity.

[0046] [1-1-3-5. Sum calculation section] The sum calculation unit 215 calculates the sum of the capacities of the indoor heat exchangers 31 provided in each of the multiple indoor units 3 installed in the space to be air-conditioned. In this embodiment, the sum of the capacities of the indoor heat exchangers 31 provided in each of the indoor units 3A to 3D is calculated. Note that the capacity of the indoor heat exchanger 31 is the volume of refrigerant that the indoor heat exchanger 31 can finish.

[0047] For example, if the outdoor memory 220 stores the capacity of the indoor heat exchanger 31 as information for each of the indoor units 3A to 3D, the sum calculation unit 215 reads out all the capacities of the indoor heat exchangers 31 from the outdoor memory 220 and calculates the sum of the read capacities. Also, for example, the sum calculation unit 215 inquires of each indoor unit 3 about the capacity of the indoor heat exchanger 31 via the outdoor communication control unit 211, and calculates the sum of the capacities of the indoor heat exchangers 31 by adding up the multiple capacities obtained by the inquiry.

[0048] [1-1-3-6.Target dehumidification amount calculation section] The target dehumidification amount calculation unit 216 calculates, for each indoor unit 3, a target dehumidification amount, which is a target dehumidification amount, based on the operation data received by the outdoor communication control unit 211. The target dehumidification amount calculation unit 216 causes the suction absolute humidity calculation unit 212 to calculate the suction absolute humidity based on the operating data to be processed, and also causes the target absolute humidity calculation unit 214 to calculate the target absolute humidity based on the operating data to be processed. The target dehumidification amount calculation unit 216 then calculates the difference between the calculated target absolute humidity and the suction absolute humidity as the target dehumidification amount. In this way, the target dehumidification amount calculation unit 216 calculates the target dehumidification amount for each indoor unit 3.

[0049] [1-1-3-7. Ratio calculation section] The ratio calculation unit 217 calculates the ratio of the capacity of the indoor heat exchanger 31 that keeps the refrigerant temperature below the dew point temperature to the sum of the capacities calculated by the sum calculation unit 215 (hereinafter referred to as "ratio of capacity to the sum").

[0050] The ratio calculation unit 217 calculates the ratio of the capacity to the total based on the target dehumidification amount with the largest value among the target dehumidification amounts calculated for each of the indoor units 3. For example, when a capacity of the indoor heat exchanger 31 per unit that keeps the refrigerant temperature equal to or lower than the dew point temperature is determined for a dehumidification amount per unit, the ratio calculation unit 217 divides the target dehumidification amount calculated by the target dehumidification amount calculation unit 216 by the dehumidification amount per unit, and multiplies the value obtained by this division by the capacity of the indoor heat exchanger 31 per unit. Then, the ratio calculation unit 217 divides the value obtained by this multiplication by the sum of the capacities calculated by the sum calculation unit 215, thereby calculating the ratio of the capacity to the sum.

[0051] [1-1-3-8. Selection Department] The selection unit 218 selects an indoor unit 3 to operate as the first indoor unit and an indoor unit 3 to operate as the second indoor unit from the multiple indoor units 3. Alternatively, the selection unit 218 selects an indoor unit 3 to operate as the first indoor unit, an indoor unit 3 to operate as the second indoor unit, and an indoor unit 3 to operate as the third indoor unit from the multiple indoor units 3.

[0052] The selection unit 218 makes the above selection based on the ratio of the capacity to the total calculated by the ratio calculation unit 217. The selection unit 218 also has the suction absolute humidity calculation unit 212 calculate the suction absolute humidity for each indoor unit 3, and makes the above selection so that the indoor unit 3 with the higher calculated suction absolute humidity becomes the first indoor unit.

[0053] Below, the selection by the selection unit 218 will be specifically explained, taking as an example a case where the relationship of the suction absolute humidities calculated by the suction absolute humidity calculation unit 212 is indoor unit 3A>indoor unit 3B>indoor unit 3C>indoor unit 3D.

[0054] [1-1-3-8-1. Example 1] In Example 1, the total capacity of the indoor heat exchangers 31 of the indoor units 3A to 3D is assumed to be "A". In Example 1, the capacity of the indoor heat exchanger 31 of the indoor unit 3A is assumed to be "α." In Example 1, it is assumed that the ratio of capacity to the total calculated by the ratio calculation unit 217 is "Z". In addition, in Example 1, the relationship is "Z≦α÷A".

[0055] In Example 1, the selection unit 218 first selects the indoor unit 3A with the highest suction absolute humidity. In Example 1, because the relationship is "Z≦α÷A", the selection unit 218 selects the indoor unit 3A as the indoor unit 3 to operate as the first indoor unit, and selects the indoor units 3B to 3D as the indoor units 3 to operate as the second indoor units.

[0056] [1-1-3-8-2. Example 2] In Example 2, the total capacity of the indoor heat exchangers 31 of the indoor units 3A to 3D is assumed to be "A." In Example 2, the capacity of the indoor heat exchanger 31 of the indoor unit 3A is assumed to be "α." In Example 2, the capacity of the indoor heat exchanger 31 of the indoor unit 3B is assumed to be "β." In Example 2, it is assumed that the ratio of capacity to the total calculated by the ratio calculation unit 217 is "Z". In addition, in Example 2, the relationship is assumed to be "Z≦(α+β)÷A".

[0057] In Example 2, the selection unit 218 selects the indoor unit 3A with the highest suction absolute humidity and the indoor unit 3B with the second highest suction absolute humidity after the indoor unit 3A. In Example 2, because the relationship "Z≦(α+β)÷A" holds, the selection unit 218 selects the indoor units 3A and 3B as the indoor units 3 to operate as first indoor units, and selects the indoor units 3C and 3D as the indoor units 3 to operate as second indoor units.

[0058] In the case of Example 2, if the capacity of the indoor heat exchanger 31 of the indoor unit 3B is a predetermined percentage (for example, 50%) and the relationship "Z<(α+β)÷A" is satisfied, the selection unit 218 may select the indoor unit 3A as the indoor unit 3 to operate as the first indoor unit, the indoor unit 3B as the indoor unit 3 to operate as the third indoor unit, and the indoor units 3C and 3D as the indoor units 3 to operate as the second indoor units.

[0059] [1-1-3-8-3. Example 3] In Example 3, the total capacity of the indoor heat exchangers 31 of the indoor units 3A to 3D is assumed to be "A." In Example 3, the capacity of the indoor heat exchanger 31 of the indoor unit 3A is assumed to be "α." In Example 3, the capacity of the indoor heat exchanger 31 of the indoor unit 3B is assumed to be "β." In Example 3, the capacity of the indoor heat exchanger 31 of the indoor unit 3C is assumed to be "γ". In Example 3, it is assumed that the ratio of the capacity to the total calculated by the ratio calculation unit 217 is "Z". In Example 3, the relationship is assumed to be "Z≦(α+β+γ)÷A".

[0060] In Example 3, the selection unit 218 selects the indoor unit 3A with the highest suction absolute humidity, the indoor unit 3B with the second highest suction absolute humidity after indoor unit 3A, and the indoor unit 3C with the second highest suction absolute humidity after indoor unit 3B. In Example 3, because the relationship "Z≦(α+β+γ)÷A" holds, the selection unit 218 selects indoor units 3A, 3B, and 3C as the indoor units 3 to operate as first indoor units, and selects indoor unit 3D as the indoor unit 3 to operate as the second indoor unit.

[0061] In the case of Example 3, if the capacity of the indoor heat exchanger 31 of the indoor unit 3C is a predetermined percentage (for example, 50%) and the relationship "Z<(α+β+γ)÷A" is satisfied, the selection unit 218 may select the indoor units 3A and 3B as the indoor units 3 to operate as the first indoor units, select the indoor unit 3C as the indoor unit 3 to operate as the third indoor unit, and select the indoor unit 3D as the indoor unit 3 to operate as the second indoor unit.

[0062] [1-1-3-9. Operation control unit] The operation control unit 219 controls the compressor 20, the four-way valve 23, the outdoor blower fan 24, and the outdoor expansion valve 26, thereby controlling the operation of the outdoor unit 2.

[0063] [1-2. Operation] Next, the operation of each part of the air conditioning system 1 involved in the latent heat and sensible heat treatment operation will be described.

[0064] [1-2-1. Operations related to the start of latent heat and sensible heat treatment operation] First, with reference to FIG. 4, the operation of each part of the air conditioning system 1 related to the start of the latent heat and sensible heat treatment operation will be described.

[0065] Fig. 4 is a sequence diagram showing the operation of the air conditioning system 1. The operation of the outdoor unit 2 shown in Fig. 4 is started when a predetermined trigger occurs. An example of the predetermined trigger is when the user changes the set temperature or set humidity.

[0066] The sum calculation unit 215 calculates the sum of the capacities of the indoor heat exchangers 31 provided in each of the multiple indoor units 3 installed in the space to be air-conditioned (step SA1).

[0067] Next, the target dehumidification amount calculation unit 216 calculates the target dehumidification amount (step SA2).

[0068] Next, the ratio calculation unit 217 calculates the ratio of the capacity to the total sum based on the total sum of the capacities calculated in step SA1 and the target dehumidification amount calculated in step SA2 (step SA3).

[0069] Next, the selection unit 218 selects the indoor unit 3 to operate as the first indoor unit and the indoor unit 3 to operate as the second indoor unit, or the indoor unit 3 to operate as the first indoor unit, the indoor unit 3 to operate as the second indoor unit, and the indoor unit 3 to operate as the third indoor unit, based on the ratio of capacity to the total calculated in step SA3 (step SA4).

[0070] Next, the outdoor communication control section 211 transmits one of the first operation instruction information, the second operation instruction information, or the third operation instruction information to each indoor unit 3 based on the selection result of step SA4 (step SA5).

[0071] Step SA5 will now be described in detail. The outdoor communication control unit 211 transmits first operation instruction information to the indoor unit 3 selected as the first indoor unit in step SA4, instructing it to operate as the first indoor unit. The outdoor communication control unit 211 also transmits second operation instruction information to the indoor unit 3 selected as the second indoor unit in step SA4, instructing it to operate as the second indoor unit. The outdoor communication control unit 211 transmits third operation instruction information to the indoor unit 3 selected as the third indoor unit, instructing it to operate as the third indoor unit.

[0072] The third operation instruction information includes information on the capacity of the indoor heat exchanger 31 that processes latent heat. A specific explanation will be given using Example 2 given as an example in the explanation of the selection unit 218. Example 2 shows a case where the indoor unit 3B may be selected as the third indoor unit. In Example 2, since the indoor unit 3A operates as the first indoor unit, it is desirable for the indoor unit 3B to process latent heat with a capacity of the indoor heat exchanger 31 of "Z÷A-α". Therefore, in Example 2, the third operation instruction information sent to the indoor unit 3B includes "Z÷A-α" as information on the capacity for processing latent heat.

[0073] Fig. 4 illustrates a case where indoor unit 3A is selected as the first indoor unit, indoor unit 3B is selected as the third indoor unit, and indoor units 3C and 3D are selected as the second indoor units. Therefore, in Fig. 4, the outdoor communication control section 211 transmits first instruction information to indoor unit 3A (step SA51), transmits third instruction information to indoor unit 3B (step SA52), and transmits second instruction information to indoor units 3C and 3D (steps SA53 and SA54).

[0074] When the indoor communication control unit 311 of the indoor unit 3A receives the first operation instruction information from the outdoor unit 2, the indoor unit 3A operates as the first indoor unit, and the expansion valve control unit 313 of the indoor unit 3A controls the indoor expansion valve 32 to start processing the latent heat (step SA6).

[0075] Furthermore, when the indoor communication control unit 311 of the indoor unit 3B receives the third operation instruction information from the outdoor unit 2, the indoor unit 3B operates as the third indoor unit, and the expansion valve control unit 313 of the indoor unit 3B controls the indoor expansion valve 32 to start processing the latent heat and sensible heat (step SA7).

[0076] Furthermore, when the indoor communication control units 311 of the indoor units 3C and 3D receive the second operation instruction information from the outdoor unit 2, the indoor units 3C and 3D operate as second indoor units, and the expansion valve control units 313 of the indoor units 3C and 3D control the indoor expansion valves 32 to start processing the sensible heat (steps SA8 and SA9).

[0077] [1-2-2. Operation of the first indoor unit] Next, the operation of the first indoor unit will be described. As described above, the first indoor unit is the indoor unit 3 that reduces the temperature of the refrigerant passing through its own indoor heat exchanger 31 to below the dew point. The first indoor unit controls the indoor expansion valve 32 to reduce the temperature of the refrigerant passing through its own indoor heat exchanger 31 to below the dew point. In addition, the outdoor unit 2 controls the rotation frequency of the compressor 20 so that the temperature of the refrigerant passing through the indoor heat exchanger 31 of the first indoor unit is reduced to below the dew point. Therefore, while explaining the operation of the first indoor unit, we will also explain the operation of the outdoor unit 2 so that the refrigerant temperature is below the dew point temperature.

[0078] First, when the first indoor unit starts to operate as the first indoor unit, the expansion valve control section 313 of the first indoor unit reduces the opening degree of the indoor expansion valve 32 by one step.

[0079] Next, the operation control unit 219 of the outdoor unit 2 causes the suction absolute humidity calculation unit 212 to calculate the suction absolute humidity and the dew point absolute humidity calculation unit 213 to calculate the dew point absolute humidity based on the operation data received from the first indoor unit, and calculates the difference between the calculated suction absolute humidity and the dew point absolute humidity. Then, if the calculated difference is not 0, the operation control unit 219 increases or decreases the rotation frequency of the compressor 20 by an amount corresponding to the calculated difference.

[0080] Next, the expansion valve control unit 313 of the first indoor unit checks whether the temperatures detected by the first refrigerant temperature sensor 33, the second refrigerant temperature sensor 34, and the third refrigerant temperature sensor 35 are lower than the dew point temperature calculated by the dew point temperature calculation unit 312.

[0081] Next, the operation control section 219 of the outdoor unit 2 calculates the suction absolute humidity based on the operation data received from the first indoor unit, and determines whether the calculated suction absolute humidity has a decreasing gradient.

[0082] If the operation control unit 219 determines that the calculated suction absolute humidity is not decreasing, the outdoor communication control unit 211 sends an instruction to the first indoor unit to decrease the opening of the indoor expansion valve 32. Then, the air conditioning system 1 again decreases the opening of the indoor expansion valve 32 of the first indoor unit by one step, adjusts the rotation frequency of the compressor 20 based on the difference between the suction absolute humidity and the dew point absolute humidity, and checks whether the refrigerant is at or below the dew point temperature.

[0083] On the other hand, when the operation control unit 219 determines that the calculated suction absolute humidity is decreasing, it continues to determine whether or not the suction absolute humidity is decreasing.

[0084] [1-2-3. Operation of the second indoor unit] Next, the operation of the second indoor unit will be described. The expansion valve control section 313 of the second indoor unit controls the opening of the indoor expansion valve 32 to decrease so that the temperature detected by the first refrigerant temperature sensor 33 corresponds to a gas-liquid two-layer state and the temperature detected by the third refrigerant temperature sensor 35 corresponds to a gas-phase state. The second indoor unit knows in advance the temperatures corresponding to the gas-liquid two-layer state and the gas-phase state, and controls the opening of the indoor expansion valve 32 by comparing the temperatures detected by the first refrigerant temperature sensor 33 and the third refrigerant temperature sensor 35 with these known temperatures.

[0085] [1-2-4. Operation of the third indoor unit] Next, the operation of the third indoor unit will be described. The expansion valve control unit 313 of the third indoor unit controls the aperture of the indoor expansion valve 32 so that the temperature detected by the first refrigerant temperature sensor 33 corresponds to the liquid phase and the temperature detected by the second refrigerant temperature sensor 34 corresponds to the gas phase. The third indoor unit knows in advance the temperatures corresponding to the liquid phase and the gas phase, and controls the aperture of the indoor expansion valve 32 by comparing the temperatures detected by the first refrigerant temperature sensor 33 and the third refrigerant temperature sensor 35 with these known temperatures. The expansion valve control unit 313 of the third indoor unit also controls the aperture of the indoor expansion valve 32 so that the latent heat can be processed with the capacity of the indoor heat exchanger 31 that processes the latent heat included in the third operation instruction information. The third indoor unit knows in advance the capacity at which the latent heat can be processed depending on the aperture of the indoor expansion valve 32, and controls the aperture of the indoor expansion valve 32 based on this knowledge.

[0086] FIG. 5 is a diagram showing the state of moist air, that is, a psychrometric chart. In the psychrometric chart shown in FIG. 5, the vertical axis is set to absolute humidity and the horizontal axis is set to dry-bulb temperature.

[0087] When the relative temperature of the air-conditioned space and the temperature of the air-conditioned space are at point P1 (relative temperature: 50%, temperature: 30°C), suppose that the user sets the set temperature to 25°C and the set humidity to 50%. If all of the indoor units 3 in the air-conditioned space process sensible heat, the temperature of the air-conditioned space will decrease toward 25°C, but the relative humidity will increase toward the dotted arrow in the diagram. Therefore, in this embodiment, a latent heat and sensible heat processing operation is performed in the air-conditioned space, including indoor units 3 that process latent heat and indoor units 3 that process sensible heat. This causes the relative temperature of the air-conditioned space and the temperature of the air-conditioned space to change toward point P2 (relative temperature: 50%, temperature: 25°C), preventing a loss of user comfort.

[0088] [1-3. Effects, etc.] As described above, the air conditioning system 1 includes the outdoor unit 2 and multiple indoor units 3 that are connected to the outdoor unit 2 by refrigerant piping RP and installed in the space to be air-conditioned. The multiple indoor units 3 perform latent heat and sensible heat processing operation, including a first indoor unit that processes latent heat and a second indoor unit that processes sensible heat.

[0089] According to this, in the multiple indoor units 3 in one refrigerant system that are installed in the space to be air-conditioned, the indoor units 3 that process latent heat and the indoor units 3 that process sensible heat are operated separately, so that the temperature and humidity of the space to be air-conditioned can be controlled simultaneously using one refrigerant system.

[0090] Furthermore, compared to a configuration that has multiple refrigerant systems and separates one system for processing latent heat and another for processing sensible heat, this system can simultaneously control the temperature and humidity of the space to be air-conditioned with a simpler system configuration.Furthermore, because the temperature and humidity of the space to be air-conditioned can be controlled with a simple system configuration, the power consumption required for controlling the temperature and humidity of the space to be air-conditioned can be reduced. Furthermore, since the indoor units 3 that process latent heat and the indoor units 3 that process sensible heat are operated separately, it is possible to avoid inefficient operation in which one indoor heat exchanger 31 processes both latent heat and sensible heat.

[0091] The air conditioning system 1 includes a sum calculation unit 215 that calculates the sum of the capacities of the indoor heat exchangers 31 included in the multiple indoor units 3. The air conditioning system 1 also includes a target dehumidification amount calculation unit 216 that calculates a target dehumidification amount for the conditioned space. The air conditioning system 1 also includes a ratio calculation unit 217 that calculates the ratio of the capacity of the indoor heat exchangers 31 that keep the refrigerant temperature at or below the dew point temperature to the sum calculated by the sum calculation unit 215, based on the target dehumidification amount calculated by the target dehumidification amount calculation unit 216. The air conditioning system 1 also includes a selection unit 218 that selects, from the multiple indoor units 3, an indoor unit 3 to operate as a first indoor unit and an indoor unit 3 to operate as a second indoor unit, based on the ratio calculated by the ratio calculation unit 217. The multiple indoor units 3 perform latent heat and sensible heat treatment operation based on the selection result of the selection unit 218.

[0092] This allows the first indoor unit to be selected from the multiple indoor units 3 so that it can dehumidify the target dehumidification amount, thereby preventing situations in which the dehumidification amount is insufficient and the comfort of the air-conditioned space is compromised. Therefore, it is possible to simultaneously control the temperature and humidity of the air-conditioned space using one refrigerant system, and to control the humidity while preventing the comfort of the air-conditioned space from being compromised.

[0093] The selection unit 218 selects, from the plurality of indoor units 3, an indoor unit 3 to operate as a first indoor unit, an indoor unit 3 to operate as a second indoor unit, and an indoor unit 3 to operate as a third indoor unit that processes latent heat and sensible heat, based on the ratio calculated by the ratio calculation unit 217. The plurality of indoor units 3, including the first indoor unit, the second indoor unit, and the third indoor unit, perform latent heat and sensible heat processing operation.

[0094] According to this, by further including indoor unit 3 that processes latent heat and sensible heat and performing latent and sensible heat processing operation, it is possible to prevent the first indoor unit from dehumidifying more than necessary. Therefore, it is possible to simultaneously control the temperature and humidity of the air-conditioned space using one refrigerant system, and to control the humidity while further preventing a loss of comfort in the air-conditioned space.

[0095] The first indoor unit controls the opening of the indoor expansion valve 32 provided therein so that the refrigerant flowing out from the indoor heat exchanger 31 provided therein is at or below the dew point temperature and in a gas-liquid two-phase state or a liquid phase state.

[0096] According to this, the indoor expansion valve 32 can properly process latent heat, and therefore the first indoor unit can properly control humidity.

[0097] (Other embodiments) As described above, the above-mentioned first embodiment has been described as an example disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the above-mentioned first embodiment to create new embodiments. Therefore, other embodiments will be exemplified below.

[0098] In the above-described embodiment, the number of indoor units 3 belonging to one refrigerant system and installed in the same air-conditioned space is four, but the number of indoor units 3 belonging to one refrigerant system and installed in the same air-conditioned space may be two or more.

[0099] In the above-described embodiment, the number of outdoor units 2 belonging to one refrigerant system is one, but the number of outdoor units 2 belonging to one refrigerant system may be two or more.

[0100] In the above-described embodiment, the outdoor unit 2 is configured to calculate the sum of the capacities of the indoor heat exchangers 31, calculate the target dehumidification amount, calculate the ratio of the capacity to the sum, and select the first and second indoor units, or the first to third indoor units. In other embodiments, a certain indoor unit 3 may calculate the sum of the capacities of the indoor heat exchangers 31, calculate the target dehumidification amount, calculate the ratio of the capacity to the sum, and select the first and second indoor units, or the first to third indoor units. That is, in other embodiments, the indoor processor 310 may function as a "sum calculation unit," a "target dehumidification amount calculation unit," a "ratio calculation unit," and a "selection unit."

[0101] The outdoor processor 210 and the indoor processor 310 may be configured with a single processor or multiple processors. These processors may be hardware programmed to realize the corresponding functional units. That is, these processors may be configured with, for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0102] The configurations of the indoor unit 3 and the outdoor unit 2 shown in Figures 2 and 3 are merely examples, and the specific implementation form is not particularly limited. In other words, it is not necessarily necessary to implement hardware corresponding to each unit individually, and it is also possible to implement a configuration in which a single processor executes a program to realize the functions of each unit. Furthermore, some of the functions realized by software in the above-mentioned embodiment may be implemented by hardware, or some of the functions realized by hardware may be implemented by software.

[0103] The step units of the operation shown in Figure 4 are divided according to the main processing content to make the operation easier to understand, and the operation is not limited by the way the processing units are divided or the names of the processing units. The operation may be divided into more step units depending on the processing content. Furthermore, one step unit may be divided so that it includes more processing. Furthermore, the order of the steps may be changed as appropriate within the scope that does not interfere with the purpose of this disclosure.

[0104] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[0105] (Addendum) The above description of the embodiments discloses the following techniques.

[0106] (Technology 1) An air conditioning system that performs latent heat and sensible heat processing operation, comprising an outdoor unit and a plurality of indoor units that are connected to the outdoor unit by refrigerant piping and installed in a space to be air-conditioned, the plurality of indoor units including a first indoor unit that processes latent heat and a second indoor unit that processes sensible heat. According to this, in the multiple indoor units in one refrigerant system that are installed in the space to be air-conditioned, the indoor units that process latent heat and the indoor units that process sensible heat are operated separately, so that the temperature and humidity of the space to be air-conditioned can be controlled simultaneously using one refrigerant system.

[0107] (Technology 2) a ratio calculation unit that calculates a ratio of the capacity of the indoor heat exchanger that keeps the refrigerant temperature below a dew point temperature to the total calculated by the sum calculation unit based on the target dehumidification amount calculated by the target dehumidification amount calculation unit; and a selection unit that selects, from the plurality of indoor units, an indoor unit to be operated as the first indoor unit and an indoor unit to be operated as the second indoor unit based on the ratio calculated by the ratio calculation unit, wherein the plurality of indoor units perform the latent heat sensible heat treatment operation based on the selection result of the selection unit. This allows the first indoor unit to be selected from the multiple indoor units so that it can dehumidify the target dehumidification amount, thereby preventing situations in which the dehumidification amount is insufficient and the comfort of the air-conditioned space is compromised. Therefore, it is possible to simultaneously control the temperature and humidity of the air-conditioned space using a single refrigerant system, and to control the humidity while preventing the comfort of the air-conditioned space from being compromised.

[0108] (Technology 3) The selection unit selects, based on the ratio calculated by the ratio calculation unit, from the plurality of indoor units, an indoor unit to operate as the first indoor unit, an indoor unit to operate as the second indoor unit, and an indoor unit to operate as a third indoor unit that processes latent heat and sensible heat, and the plurality of indoor units perform the latent heat and sensible heat processing operation, including the first indoor unit, the second indoor unit, and the third indoor unit. According to this, by further including an indoor unit that processes latent heat and sensible heat and performing latent and sensible heat processing operation, it is possible to prevent the first indoor unit from dehumidifying more than necessary. Therefore, it is possible to simultaneously control the temperature and humidity of the air-conditioned space using a single refrigerant system, and to control the humidity while further preventing a loss of comfort in the air-conditioned space.

[0109] (Technology 4) The air conditioning system according to any one of Techniques 1 to 3, wherein the first indoor unit controls an opening degree of an indoor expansion valve provided therein so that the refrigerant flowing out from the indoor heat exchanger provided therein is at a dew point temperature or lower and in a gas-liquid two-phase state or a liquid phase state. According to this, latent heat can be properly processed by the indoor expansion valve, and humidity control can be properly performed by the first indoor unit. [Industrial Applicability]

[0110] As described above, the air conditioning system according to the present invention can be used to simultaneously control the temperature and humidity of a space to be air-conditioned. [Explanation of symbols]

[0111] 1. Air conditioning system 2 Outdoor unit 3, 3A~3D indoor unit 20 Compressor 21 Gas-liquid separator 22 Oil separator 23 Four-way valve 24 Outdoor ventilation fan 25 Outdoor heat exchanger 26 Outdoor expansion valve 30 Indoor ventilation fan 31 Indoor heat exchanger 32 Indoor expansion valve 33 First refrigerant temperature sensor 34 Second refrigerant temperature sensor 35 Third refrigerant temperature sensor 200 Outdoor control unit 201 Outdoor Communications Department 210 Outdoor Processor 211 Outdoor communication control unit 212 Intake absolute humidity calculation section 213 Dew point absolute humidity calculation section 214 Target absolute humidity calculation unit 215 Summation calculation unit 216 Target dehumidification amount calculation section 217 Percentage Calculation Section 218 Selection Department 219 Operation control unit 220 Outdoor Memory 221 Control Program 300 Indoor control unit 300 Indoor Processor 301 Indoor Communications Department 302 Intake temperature sensor 303 Intake humidity sensor 304 Air outlet temperature sensor 310 Indoor Processor 311 Indoor communication control unit 312 Dew point temperature calculation section 313 Expansion valve control section 320 Indoor Memory 321 Control Program RP refrigerant piping

Claims

1. The outdoor unit and a plurality of indoor units connected to the outdoor unit by refrigerant piping and installed in the space to be air-conditioned; the plurality of indoor units perform a latent heat and sensible heat treatment operation, including a first indoor unit that treats latent heat and a second indoor unit that treats sensible heat; Air conditioning system.

2. a sum calculation unit that calculates the sum of the capacities of the heat exchangers provided in the plurality of indoor units; a target dehumidification amount calculation unit that calculates a target dehumidification amount for the conditioned space; a ratio calculation unit that calculates a ratio of a capacity of the heat exchanger that keeps a refrigerant temperature equal to or lower than a dew point temperature to the sum calculated by the sum calculation unit based on the target dehumidification amount calculated by the target dehumidification amount calculation unit; a selection unit that selects, from the plurality of indoor units, an indoor unit to be operated as the first indoor unit and an indoor unit to be operated as the second indoor unit based on the ratio calculated by the ratio calculation unit, The indoor units perform the latent heat and sensible heat treatment operation based on the selection result of the selection unit. The air conditioning system of claim 1 .

3. the selection unit selects, from the plurality of indoor units, an indoor unit to be operated as the first indoor unit, an indoor unit to be operated as the second indoor unit, and an indoor unit to be operated as a third indoor unit that processes latent heat and sensible heat, based on the ratio calculated by the ratio calculation unit; the plurality of indoor units perform the latent heat and sensible heat treatment operation, including the first indoor unit, the second indoor unit, and the third indoor unit; 3. The air conditioning system of claim 2.

4. The first indoor unit controls the opening degree of the indoor expansion valve so that the refrigerant flowing out from the heat exchanger is at a dew point temperature or lower and in a gas-liquid two-phase state or a liquid phase state.

3. The air conditioning system according to claim 1 or 2.

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