Indoor temperature estimation method and indoor temperature estimation system

Abstract

An indoor temperature estimation method performed by an indoor temperature estimation system (101) involves estimating the indoor temperature when the operation of a refrigeration cycle device (1) is stopped. After an outdoor unit (2) or an indoor unit (5) is stopped, the indoor temperature is estimated on the basis of a refrigerant temperature (TH1) detected by an indoor heat exchanger inlet temperature sensor (56) and a refrigerant temperature (TH2) detected by an indoor heat exchanger outlet temperature sensor (57).

Description

Indoor temperature estimation method and indoor temperature estimation system

[0001] The present invention relates to an indoor temperature estimation method and an indoor temperature estimation system.

[0002] Conventionally, the indoor temperature is estimated using a temperature sensor installed in advance in the room (Patent Document 1 (JP-A-11-351637)).

[0003] However, conventional indoor temperature estimation methods have a problem in that they may require the installation of a new sensor.

[0004] The indoor temperature estimation method according to a first aspect is a method for estimating the indoor temperature when the operation of a refrigeration cycle device is stopped. After the outdoor unit or the indoor unit is stopped, the indoor temperature is estimated based on the refrigerant temperature detected by the temperature sensor in the indoor unit.

[0005] In this indoor temperature estimation method, when the operation of the refrigeration cycle device is stopped, the indoor temperature can be estimated because the refrigerant temperature detected by the temperature sensor of the indoor unit reflects the indoor temperature.

[0006] The indoor temperature estimation method of the second aspect is the method of the first aspect, in which the indoor temperature from a predetermined time onwards is estimated based on the refrigerant temperature detected by the indoor heat exchanger inlet temperature sensor of the indoor unit or the refrigerant temperature detected by the indoor heat exchanger outlet temperature sensor of the indoor unit.

[0007] This indoor temperature estimation method makes it possible to estimate the indoor temperature from a predetermined time onward without installing an additional sensor.

[0008] The indoor temperature estimation method according to a third aspect is the method according to the second aspect, wherein the predetermined time includes a first time. The first time is a time when the refrigerant circuit of the refrigeration cycle device is pressure equalized after the outdoor unit has stopped.

[0009] This indoor temperature estimation method makes it possible to estimate the indoor temperature from the time when the refrigerant circuit is pressure-equalized after the indoor unit has stopped.

[0010] The indoor temperature estimation method of the fourth aspect is the method of the third aspect, and determines that the refrigerant circuit is pressure-equalized when the difference in absolute values ​​between the condensing temperature and the evaporating temperature is equal to or less than a predetermined value. The condensing temperature is calculated from the discharge pressure detected by a discharge pressure sensor of the compressor of the outdoor unit. The evaporating temperature is calculated from the suction pressure detected by a suction pressure sensor of the compressor of the outdoor unit. Alternatively, the refrigerant circuit is determined to be pressure-equalized when the difference in absolute values ​​between the discharge pressure and the suction pressure is equal to or less than a predetermined value.

[0011] In this indoor temperature estimation method, the pressure equalization of the refrigerant circuit can be determined using the discharge pressure and suction pressure of the compressor.

[0012] An indoor temperature estimation method according to a fifth aspect is the method according to the second aspect, wherein the predetermined time includes a second time. The second time is a time when a certain time has elapsed after the indoor unit has stopped.

[0013] This indoor temperature estimation method can estimate the indoor temperature after a certain time has passed since the indoor unit was stopped.

[0014] The indoor temperature estimation method of the sixth aspect is the method of the third or fourth aspect, and estimates the indoor temperature between the stop time of the indoor unit and the first time by adding a correction value to the intake air temperature detected by the intake air temperature sensor of the indoor unit at the stop time of the indoor unit.

[0015] In this indoor temperature estimation method, the indoor temperature between the time the indoor unit is stopped and the time the refrigerant circuit is pressure equalized can be estimated by correcting the intake air temperature of the indoor unit.

[0016] The seventh aspect of the indoor temperature estimation method is the method of the fifth aspect, and estimates the indoor temperature between the time the indoor unit is stopped and the second time by adding a correction value to the intake air temperature detected by the intake air temperature sensor of the indoor unit at the time the indoor unit is stopped.

[0017] This indoor temperature estimation method corrects the intake air temperature of the indoor unit, making it possible to estimate the indoor temperature between the time the indoor unit is stopped and the time a certain amount of time has passed since the indoor unit was stopped.

[0018] An indoor temperature estimation method according to an eighth aspect is the method according to the third or fourth aspect, in which the stop time of the indoor unit is set as a start point, and a first time is set as a first end point. The indoor temperature at times between the start point and the first end point is estimated using a predetermined function using a first calculated value calculated based on the intake air temperature detected by the intake air temperature sensor of the indoor unit at the start point, and the refrigerant temperatures detected by the indoor heat exchanger inlet temperature sensor and the indoor heat exchanger outlet temperature sensor at the first end point.

[0019] This indoor temperature estimation method makes it possible to estimate the indoor temperature between the time the indoor unit is stopped and the time the refrigerant circuit is pressure equalized.

[0020] A ninth aspect of the indoor temperature estimation method is the method of the fifth aspect, wherein a start point is a time when the indoor unit is stopped, and a second time is a second end point. The indoor temperature at times between the start point and the second end point is estimated using a predetermined function using an intake air temperature detected by an intake air temperature sensor of the indoor unit at the start point and a second calculated value calculated based on a refrigerant temperature detected by an indoor heat exchanger inlet temperature sensor and a refrigerant temperature detected by an indoor heat exchanger outlet temperature sensor at the second end point.

[0021] This indoor temperature estimation method makes it possible to estimate the indoor temperature between the time the indoor unit is stopped and the time a certain amount of time has elapsed since the indoor unit was stopped.

[0022] The indoor temperature estimation method of the tenth aspect is any of the methods of the first aspect to the ninth aspect, in which, in an indoor space where two or more indoor units are installed, a representative indoor temperature of the indoor space is estimated using each indoor temperature estimated by each indoor unit.

[0023] This indoor temperature estimation method makes it possible to estimate a representative indoor temperature even when multiple indoor units are installed in an indoor space.

[0024] An indoor temperature estimation system according to an eleventh aspect is a system for estimating the indoor temperature when the operation of a refrigeration cycle device is stopped. The indoor temperature estimation system includes a refrigerant circuit and an estimation unit. The refrigerant circuit connects an outdoor unit and an indoor unit via a communication pipe. The estimation unit estimates the indoor temperature after the outdoor unit or the indoor unit stops. The indoor unit has a temperature sensor that detects the refrigerant temperature. The estimation unit estimates the indoor temperature based on the refrigerant temperature detected by the temperature sensor.

[0025] In this indoor temperature estimation system, when the operation of the refrigeration cycle device is stopped, the indoor temperature can be estimated because the refrigerant temperature detected by the temperature sensor provided in the indoor unit reflects the indoor temperature.

[0026] The indoor temperature estimation system of a twelfth aspect is the system of the eleventh aspect, further comprising a determination unit that determines whether a predetermined time has elapsed.

[0027] In this indoor temperature estimation system, the determination unit determines whether a predetermined time has elapsed, so that the indoor temperature can be estimated at an appropriate timing after the outdoor unit or the indoor unit has stopped.

[0028] 1 is a schematic diagram of an indoor temperature estimation system. FIG. 2 is a schematic diagram of a refrigeration cycle device. FIG. 3 is a block diagram of a control unit of a refrigeration cycle device. FIG. 4 is a diagram for explaining an example of indoor temperatures after the time when the refrigerant circuit is pressure equalized. FIG. 5 is a flowchart showing an example of processing by the indoor temperature estimation system. FIG. 6 is a diagram showing an example of the degree of increase in intake air temperature when the indoor unit is stopped. FIG. 7 is a diagram showing an example of measured values ​​of the indoor heat exchanger inlet temperature sensor and the indoor heat exchanger outlet temperature sensor when the indoor unit is stopped and when the compressor is operating. FIG. 7 is a flowchart showing another example of processing by the indoor temperature estimation system. FIG. 8 is a flowchart showing another example of processing by the indoor temperature estimation system. FIG. 9 is a diagram for explaining an example of indoor temperatures from the time when the indoor unit is stopped to the time when the refrigerant pressure is equalized. FIG. 9 is a flowchart showing another example of processing by the indoor temperature estimation system.

[0029] (1) Overall Configuration An indoor temperature estimation system 101 according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the indoor temperature estimation system 101. As shown in FIG. 1, the indoor temperature estimation system 101 mainly includes an air conditioner (refrigeration cycle apparatus) 1 and an estimation device 110. The air conditioner 1 and the estimation device 110 are connected via a network 90. ​​The indoor temperature estimation system 101 estimates the indoor temperature in a space to be air-conditioned by the air conditioner 1.

[0030] (2) Detailed Configuration (2-1) Refrigeration Cycle Device As shown in FIG. 2 , a refrigeration cycle device according to one embodiment of the present disclosure is an air conditioner 1 used for indoor cooling and heating in a building or the like by performing a vapor compression refrigeration cycle operation. The air conditioner 1 is mainly composed of a refrigerant circuit 10. The refrigerant circuit 10 has a compressor 21, a condenser, an expansion mechanism, and an evaporator. The condenser is an outdoor heat exchanger 24 mounted in the outdoor unit 2 during cooling operation, and an indoor heat exchanger 52 mounted in the indoor unit 5 during heating operation. The expansion mechanism includes an expansion valve 25. The evaporator is the indoor heat exchanger 52 mounted in the indoor unit 5 during cooling operation, and the outdoor heat exchanger 24 mounted in the outdoor unit 2 during heating operation.

[0031] The refrigerant circuit 10 is filled with, for example, a fluorocarbon-based refrigerant. Note that the refrigerant filled in the refrigerant circuit 10 of the present disclosure is not particularly limited.

[0032] (2-1-1) Air Conditioner As shown in Figure 2, the air conditioner 1 has an outdoor unit 2, indoor units 5, a liquid refrigerant connection pipe 6, and a gas refrigerant connection pipe 7. In this embodiment, one indoor unit 5 is provided, but multiple indoor units may be connected in parallel. The liquid refrigerant connection pipe 6 and the gas refrigerant connection pipe 7 connect the outdoor unit 2 and the indoor units 5.

[0033] (2-1-1-1) Indoor Unit The indoor unit (indoor unit) 5 is installed indoors in a building, etc. The indoor unit 5 is connected to the outdoor unit 2 via a liquid refrigerant connection pipe 6 and a gas refrigerant connection pipe 7, and constitutes part of the refrigerant circuit 10.

[0034] Next, the configuration of the indoor unit 5 will be described.

[0035] The indoor unit 5 mainly includes an indoor heat exchanger 52 , an indoor liquid refrigerant pipe 53 , an indoor gas refrigerant pipe 54 , and an indoor fan 55 .

[0036] The indoor heat exchanger 52 exchanges heat between the refrigerant and the indoor air. The indoor heat exchanger 52 functions as a refrigerant evaporator to cool the indoor air during cooling operation, and functions as a refrigerant condenser to heat the indoor air during heating operation.

[0037] The indoor liquid refrigerant pipe 53 connects the liquid side end of the indoor heat exchanger 52 to the liquid refrigerant communication pipe 6. The indoor gas refrigerant pipe 54 connects the gas side end of the indoor heat exchanger 52 to the gas refrigerant communication pipe 7.

[0038] The indoor fan 55 draws indoor air into the indoor unit 5, exchanges heat with the refrigerant in the indoor heat exchanger 52, and then supplies the air to the room as supply air. The indoor fan 55 supplies the indoor air to the indoor heat exchanger 52 as a heating or cooling source for the refrigerant flowing through the indoor heat exchanger 52.

[0039] Various sensors are provided in the indoor unit 5. Specifically, the indoor unit 5 has an indoor heat exchanger inlet temperature sensor 56, an indoor heat exchanger outlet temperature sensor 57, and an intake air temperature sensor 58.

[0040] The indoor heat exchanger inlet temperature sensor (liquid pipe thermistor) 56 detects the temperature TH1 of the refrigerant at the liquid side end of the indoor heat exchanger 52. The indoor heat exchanger inlet temperature sensor 56 is an evaporator inlet temperature sensor that measures the inlet temperature of the evaporator when the indoor heat exchanger 52 is used as an evaporator. The indoor heat exchanger inlet temperature sensor 56 is also a condenser outlet temperature sensor that measures the outlet temperature of the condenser when the indoor heat exchanger 52 is used as a condenser.

[0041] The indoor heat exchanger outlet temperature sensor (gas pipe thermistor) 57 detects the temperature TH2 of the refrigerant at the gas side end of the indoor heat exchanger 52. The indoor heat exchanger outlet temperature sensor 57 is an evaporator outlet temperature sensor that measures the outlet temperature of the evaporator when the indoor heat exchanger 52 is used as an evaporator. The indoor heat exchanger outlet temperature sensor 57 is a condenser inlet temperature sensor that measures the inlet temperature of the condenser when the indoor heat exchanger 52 is used as a condenser.

[0042] The intake air temperature sensor (intake thermistor) 58 detects the intake air temperature TH3 of the indoor unit 5.

[0043] (2-1-1-2) Outdoor Unit The outdoor unit (outdoor unit) 2 is installed outdoors in a building, etc. The outdoor unit 2 is connected to the indoor unit 5 via a liquid refrigerant connection pipe 6 and a gas refrigerant connection pipe 7, and constitutes part of the refrigerant circuit 10.

[0044] Next, we will explain the configuration of the outdoor unit 2. The outdoor unit 2 mainly has a compressor 21, a switching mechanism 23, an outdoor heat exchanger 24, an expansion valve 25, an outdoor liquid refrigerant pipe 26, a suction pipe 27, an accumulator 28, a discharge pipe 29, a first outdoor gas refrigerant pipe 30, a second outdoor gas refrigerant pipe 31, a liquid-side shut-off valve 32, a gas-side shut-off valve 33, and an outdoor fan 34.

[0045] The compressor 21 is a device that compresses a low-pressure refrigerant to a high pressure. In this example, a hermetically sealed compressor is used as the compressor 21, in which a rotary, scroll, or other positive displacement compression element (not shown) is rotationally driven by a compressor motor 22.

[0046] The switching mechanism 23 is a four-way switching valve capable of switching the flow direction of refrigerant in the refrigerant circuit 10. During cooling operation, the switching mechanism 23 is capable of switching the suction side of the compressor 21 to communicate with the gas refrigerant communication pipe 7 through the suction pipe 27 and the second outdoor gas refrigerant pipe 31, and the discharge side of the compressor 21 to communicate with the gas side end of the outdoor heat exchanger 24 through the discharge pipe 29 and the first outdoor gas refrigerant pipe 30. Therefore, by switching the switching mechanism 23, the refrigerant circuit 10 can be switched to a cooling cycle state (see the solid line of the switching mechanism 23 in FIG. 2 ) in which the outdoor heat exchanger 24 functions as a refrigerant condenser and the indoor heat exchanger 52 functions as a refrigerant evaporator. During heating operation, the switching mechanism 23 is capable of switching between connecting the suction side of the compressor 21 to the gas side end of the outdoor heat exchanger 24 through the suction pipe 27 and the first outdoor gas refrigerant pipe 30 and connecting the discharge side of the compressor 21 to the gas refrigerant communication pipe 7 through the discharge pipe 29 and the second outdoor gas refrigerant pipe 31. Therefore, by switching the switching mechanism 23 in this way, the refrigerant circuit 10 can be switched to a heating cycle state (see the dashed lines of the switching mechanism 23 in FIG. 2 ) in which the outdoor heat exchanger 24 functions as a refrigerant evaporator and the indoor heat exchanger 52 functions as a refrigerant condenser. The switching mechanism 23 is not limited to a four-way switching valve, and may be configured to switch the refrigerant flow direction as described above by combining a plurality of solenoid valves and refrigerant pipes.

[0047] The outdoor heat exchanger 24 exchanges heat between the refrigerant and the outdoor air. The outdoor heat exchanger 24 functions as a refrigerant condenser during cooling operation and as a refrigerant evaporator during heating operation. The liquid side end of the outdoor heat exchanger 24 is connected to an outdoor liquid refrigerant pipe 26, and the gas side end is connected to a first outdoor gas refrigerant pipe 30.

[0048] The expansion valve 25 is an electrically operated expansion valve whose opening degree can be adjusted to adjust the flow rate of the refrigerant flowing through the liquid refrigerant communication pipe 6. The expansion valve 25 is provided in the outdoor liquid refrigerant pipe 26.

[0049] The outdoor liquid refrigerant pipe 26 connects the liquid side end of the outdoor heat exchanger 24 to the liquid refrigerant communication pipe 6. The suction pipe 27 connects the switching mechanism 23 to the suction side of the compressor 21.

[0050] The suction pipe 27 is provided with an accumulator 28 that temporarily stores the refrigerant that is drawn into the compressor 21. In other words, the accumulator 28 stores excess refrigerant.

[0051] The discharge pipe 29 connects the discharge side of the compressor 21 to the switching mechanism 23. The first outdoor gas refrigerant pipe 30 connects the switching mechanism 23 to the gas side end of the outdoor heat exchanger 24. The second outdoor gas refrigerant pipe 31 connects the gas refrigerant communication pipe 7 to the switching mechanism 23. A liquid-side shut-off valve 32 is provided at the connection point of the outdoor liquid refrigerant pipe 26 with the liquid refrigerant communication pipe 6. A gas-side shut-off valve 33 is provided at the connection point of the second outdoor gas refrigerant pipe 31 with the gas refrigerant communication pipe 7. The liquid-side shut-off valve 32 and the gas-side shut-off valve 33 are valves that are opened and closed manually.

[0052] The outdoor fan 34 draws outdoor air into the outdoor unit 2, exchanges heat with the refrigerant in the outdoor heat exchanger 24, and then discharges the air to the outside of the outdoor unit 2. The outdoor fan 34 supplies the outdoor air to the outdoor heat exchanger 24 as a cooling or heating source for the refrigerant flowing through the outdoor heat exchanger 24.

[0053] Various sensors are provided in the outdoor unit 2. Specifically, the outdoor unit 2 has a suction pressure sensor 41, a suction temperature sensor 42, a discharge pressure sensor 43, and a discharge temperature sensor 44. The suction pressure sensor 41, the suction temperature sensor 42, the discharge pressure sensor 43, and the discharge temperature sensor 44 are provided around the compressor 21 of the outdoor unit 2.

[0054] The suction pressure sensor 41 detects the suction pressure Lp of the compressor 21. The suction temperature sensor 42 detects the suction temperature Ts of the compressor 21. The discharge pressure sensor 43 detects the discharge pressure Hp of the compressor 21. The discharge temperature sensor 44 detects the discharge temperature Td of the compressor 21.

[0055] (2-1-2) Connecting Pipes The connecting pipes include a liquid refrigerant connecting pipe 6 and a gas refrigerant connecting pipe 7. The liquid refrigerant connecting pipe 6 and the gas refrigerant connecting pipe 7 are refrigerant pipes that are installed on-site when an air conditioner equipped with the refrigerant circuit 10 is installed at an installation location such as a building, and pipes of various lengths and diameters are used depending on installation conditions such as the installation location and the combination of the outdoor unit 2 and the indoor unit 5.

[0056] The refrigerant flowing through the liquid refrigerant communication pipe 6 may be liquid or may be in a gas-liquid two-phase state.

[0057] (2-1-3) Control Unit The control unit 8 has an outdoor control unit 48 and an indoor control unit 59. As shown in Fig. 3, the control unit 8 is connected so as to be able to receive detection signals from the various sensors 41 to 44, 56, 57, and 58, and is also connected so as to be able to control various devices, the compressor 21, the switching mechanism 23, the outdoor fan 34, the expansion valve 25, the indoor fan 55, etc. based on these detection signals. The control unit 8 has a memory (not shown).

[0058] (2-1-4) Operational Behavior The air conditioner 1 performs heating and cooling operations using the refrigerant circuit 10.

[0059] (2-1-4-1) Cooling Operation Cooling operation will be described with reference to Fig. 2. In cooling operation, the switching mechanism 23 switches so that the refrigerant circuit 10 is in a cooling cycle state (the state indicated by the solid line of the switching mechanism 23 in Fig. 2). This starts the compressor 21, the outdoor fan 34, and the indoor fan 55, and the expansion valve 25 and other components perform their predetermined operations.

[0060] Then, the low-pressure gas refrigerant in the refrigerant circuit 10 is drawn into the compressor 21 and compressed to become high-pressure gas refrigerant. This high-pressure gas refrigerant is sent to the outdoor heat exchanger 24 through the switching mechanism 23.

[0061] The high-pressure gas refrigerant sent to the outdoor heat exchanger 24 is cooled and condensed in the outdoor heat exchanger 24, which functions as a refrigerant condenser, by heat exchange with outdoor air supplied by the outdoor fan 34. This high-pressure liquid refrigerant is reduced in pressure by the expansion valve 25 and becomes low-pressure refrigerant in a gas-liquid two-phase state. This low-pressure refrigerant in a gas-liquid two-phase state is sent to the indoor heat exchanger 52 through the liquid-side shut-off valve 32 and the liquid refrigerant communication pipe 6.

[0062] The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchanger 52 is heated and evaporated in the indoor heat exchanger 52, which functions as a refrigerant evaporator, by exchanging heat with indoor air supplied by the indoor fan 55. This low-pressure gas refrigerant is sent from the indoor unit 5 to the outdoor unit 2 through the gas refrigerant communication pipe 7.

[0063] The low-pressure gas refrigerant sent to the outdoor unit 2 passes through the gas-side shut-off valve 33 and the switching mechanism 23 and is sucked into the compressor 21 again.

[0064] (2-1-4-2) Heating Operation Heating operation will be described with reference to Fig. 2. In heating operation, the switching mechanism 23 switches so that the refrigerant circuit 10 is in a heating cycle state (the state indicated by the dashed line of the switching mechanism 23 in Fig. 2), the compressor 21, the outdoor fan 34, and the indoor fan 55 start up, and the expansion valve 25 and the like perform predetermined operations.

[0065] Then, the low-pressure gas refrigerant in the refrigerant circuit 10 is sucked into the compressor 21 and compressed to become high-pressure gas refrigerant. This high-pressure gas refrigerant is sent from the outdoor unit 2 to the indoor unit 5 through the switching mechanism 23, the gas-side shut-off valve 33, and the gas refrigerant communication pipe 7. The high-pressure gas refrigerant sent to the indoor unit 5 is sent to the indoor heat exchanger 52.

[0066] The high-pressure gas refrigerant sent to the indoor heat exchanger 52, which functions as a refrigerant condenser, is cooled and condensed by heat exchange with indoor air supplied by the indoor fan 55 in the indoor heat exchanger 52, which functions as a refrigerant condenser, to become high-pressure liquid refrigerant. This high-pressure liquid refrigerant is sent from the indoor unit 5 to the outdoor unit 2 through the liquid refrigerant communication pipe 6.

[0067] The refrigerant sent to the outdoor unit 2 is sent to the expansion valve 25 through the liquid-side shut-off valve 32, and is reduced in pressure by the expansion valve 25 to become low-pressure refrigerant in a gas-liquid two-phase state. This low-pressure refrigerant in a gas-liquid two-phase state is sent to the outdoor heat exchanger 24.

[0068] The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 24 is heated and evaporated in the outdoor heat exchanger 24, which functions as a refrigerant evaporator, by exchanging heat with outdoor air supplied by the outdoor fan 34. This low-pressure gas refrigerant is then sucked back into the compressor 21 via the switching mechanism 23.

[0069] (2-2) Estimation Device The estimation device 110 is a computer located on the cloud. The estimation device 110 may be installed, for example, in a refrigeration cycle device. The estimation device 110 includes an acquisition unit 111, a storage unit 112, and a control unit 113.

[0070] (2-2-1) Acquisition Unit The acquisition unit 111 acquires the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57. The acquisition unit 111 also acquires the intake air temperature TH3 detected by the intake air temperature sensor 58.

[0071] The acquisition unit 111 also acquires the suction pressure Lp of the compressor 21 from the suction pressure sensor 41 and the discharge pressure Hp of the compressor 21 from the discharge pressure sensor 43 .

[0072] (2-2-2) Storage Unit The storage unit 112 stores programs executed by the control unit 113, data necessary for executing the programs, etc. In this embodiment, the storage unit 112 particularly stores the refrigerant temperatures TH1, TH2 and the intake air temperature TH3 acquired by the acquisition unit 111. The storage unit 112 can be used as a database.

[0073] (2-2-3) Control Unit The control unit 113 is realized by a computer. The control unit 113 includes a control and arithmetic unit (not shown). A processor such as a CPU or a GPU can be used as the control and arithmetic unit. The control and arithmetic unit reads out a program stored in the storage unit 112 and performs predetermined image processing and arithmetic processing in accordance with the program. Furthermore, the control and arithmetic unit can write the results of calculations to the storage unit 112 and read out information stored in the storage unit 112 in accordance with the program.

[0074] As shown in FIG. 1 , the control unit 113 includes a determination unit 114 and an estimation unit 115 .

[0075] (2-2-3-1) Determination Unit The determination unit 114 determines whether a predetermined time has elapsed after the indoor unit 5 was stopped. In the indoor temperature estimation system 101 of this embodiment, the predetermined time is the time (first time) when the refrigerant circuit 10 of the refrigeration cycle apparatus 1 is pressure-equalized after the outdoor unit 2 is stopped.

[0076] The determination unit 114 calculates the condensing temperature from the discharge pressure Hp detected by the discharge pressure sensor 43 of the compressor 21 of the outdoor unit 2. The determination unit 114 also calculates the evaporating temperature from the suction pressure Lp detected by the suction pressure sensor 41 of the compressor 21 of the outdoor unit 2.

[0077] The determination unit 114 determines that the refrigerant circuit 10 is pressure-equalized when the difference in absolute values ​​(absolute difference) between the condensation temperature and the evaporation temperature is equal to or less than a predetermined value. In this embodiment, the determination unit 114 determines that the refrigerant circuit 10 is pressure-equalized when the absolute difference between the condensation temperature and the evaporation temperature is 1°C or less, but the absolute difference between the condensation temperature and the evaporation temperature is not limited to this. The determination unit 114 may also determine that the refrigerant circuit 10 is pressure-equalized when the difference in absolute values ​​between the discharge pressure Hp and the suction pressure Lp is equal to or less than a predetermined value.

[0078] (2-2-3-2) Estimation Unit The estimation unit 115 estimates the indoor temperature from a predetermined time onward based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57. Specifically, the estimation unit 115 estimates the indoor temperature from the predetermined time onward based on the average value of the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57. The indoor temperature from the predetermined time onward is not limited to the indoor temperature at the predetermined time, but also includes times after the predetermined time.

[0079] The estimation unit 115 may estimate the indoor temperature from a specified time onwards based on either the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 or the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57.

[0080] An example of the indoor temperature after the pressure in the refrigerant circuit 10 is equalized is shown in Fig. 4. Fig. 4 shows the sensor value when the refrigerant operation is stopped.

[0081] When the operation of the indoor unit 5 is stopped, the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 increase and become constant over time. Therefore, as shown in Figure 4, the average value TH2 of the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature detected by the indoor heat exchanger outlet temperature sensor 57 become constant over time after the operation of the indoor unit 5 is stopped.

[0082] Thereafter, when the operation of the outdoor unit 2 is stopped, the condensing temperature calculated from the discharge pressure Hp of the compressor 21 of the outdoor unit 2 decreases, and the temperature change becomes smaller as time passes. Also, when the operation of the outdoor unit 2 is stopped, the evaporating temperature calculated from the suction pressure Lp of the compressor 21 of the outdoor unit 2 increases, and the temperature change becomes smaller as time passes.

[0083] The time when the absolute difference between the condensing temperature and the evaporating temperature becomes 1°C or less is defined as the refrigerant pressure equalization time. The refrigerant pressure equalization time is, for example, two hours after the indoor unit 5 is stopped. The refrigerant temperature at the refrigerant pressure equalization time is room temperature. Therefore, the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 at the refrigerant pressure equalization time reflect the indoor temperature. As a result, the estimation unit 115 estimates the average value of the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 at the refrigerant pressure equalization time as the indoor temperature.

[0084] (3) Indoor Temperature Estimation Method An example of the processing of the indoor temperature estimation system 101 will be described using the flowchart in Fig. 5. Fig. 5 shows an example of estimating the indoor temperature when cooling operation is stopped, but the indoor temperature when heating operation is stopped may also be estimated.

[0085] In step S1, the indoor unit 5 of the air conditioner 1 that was performing cooling operation stops operation.

[0086] In step S2, the outdoor unit 2 of the air conditioner 1 that was performing cooling operation stops operation.

[0087] In step S3 , the acquisition unit 111 acquires the discharge pressure Hp of the compressor 21 detected by the discharge pressure sensor 43 of the outdoor unit 2 .

[0088] In step S4 , the acquisition unit 111 acquires the suction pressure Lp of the compressor 21 detected by the suction pressure sensor 41 of the indoor unit 2 .

[0089] In step S5, the determination unit 114 calculates the condensing temperature from the discharge pressure Hp acquired in step S3, and calculates the evaporating temperature from the suction pressure Lp acquired in step S4. The determination unit 114 determines whether the absolute difference between the calculated condensing temperature and the evaporating temperature is 1°C or less. If the absolute difference between the condensing temperature and the evaporating temperature is 1°C or less, the determination unit 114 determines that the refrigerant circuit 10 has been pressure-equalized and that it is time for refrigerant pressure equalization. If it is time for refrigerant pressure equalization (Yes in step S5), the process proceeds to step S6.

[0090] In step S6 , the acquisition unit 111 acquires the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 .

[0091] In step S7, the acquisition unit 111 acquires the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 of the indoor unit 5.

[0092] In step S8, the estimation unit 115 estimates the indoor temperature based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 obtained in step S6 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 obtained in step S7. In this embodiment, the estimator 115 estimates the indoor temperature after the refrigerant pressure equalization time to be the average value of the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57. The estimator 115 may estimate the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 or the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 to be the indoor temperature after the refrigerant pressure equalization time.

[0093] (4) Features (4-1) The indoor temperature estimation method by the indoor temperature estimation system 101 of this embodiment is a method for estimating the indoor temperature when the operation of the refrigeration cycle apparatus 1 is stopped. After the indoor unit 5 is stopped, the indoor temperature is estimated based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57.

[0094] Conventionally, when performing air conditioning load predictions or comfort assessments based on indoor environments, indoor temperatures are generally calculated using the air conditioner's intake air temperature sensor (intake thermistor). However, when the air conditioning stops blowing air, the temperature near the intake air temperature sensor rises due to factors such as heat generated by the electrical components inside the indoor unit, resulting in a discrepancy between the intake temperature and the indoor temperature. Conventional technologies estimate indoor temperatures by eliminating this discrepancy through control of the expansion valve or the blower fan. Alternatively, conventional technologies estimate indoor temperatures using temperature sensors installed in the room in advance. However, these conventional technologies require new controls and the installation of new sensors, making them difficult to implement, especially in existing buildings, given the development and sensor installation costs.

[0095] Furthermore, indoor temperature is often monitored for air conditioning control and comfort assessment, but it is typically monitored while the air conditioner is operating. Meanwhile, advanced energy management services such as comfort demand require highly accurate thermal load predictions, especially thermal storage load predictions, which are significantly affected by the indoor temperature when the air conditioner is off. Therefore, accurately measuring the indoor temperature when the air conditioner is off is a challenge that cannot be faced without specifically developing comfort demand, and is therefore not easily conceived. In other words, conventional energy-saving services often measure the indoor temperature only when the air conditioner is operating (when the indoor unit's blower fan is running). Therefore, the measurement value of the intake air temperature sensor is nearly equal to the indoor temperature, and there is no thought of using a refrigerant temperature sensor, which deviates significantly from the indoor temperature when the air conditioner is operating, to estimate the indoor temperature.

[0096] In the indoor temperature estimation system 101, after the time when the difference between the evaporating temperature and condensing temperature of the outdoor unit 2 falls below the threshold, it is determined that the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57 on the indoor unit 5 side reflect the indoor temperature, and the indoor temperature is estimated by calculating a representative indoor temperature using the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57. In this way, by using the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57, which are generally installed away from the electrical components inside the indoor unit, it is possible to estimate the indoor temperature with high accuracy using only the equipment sensors when the air conditioning is stopped, without incurring costs for additional control or sensor installation.

[0097] An example of the degree of increase in intake air temperature when the indoor unit 5 is stopped is shown in FIG.

[0098] 6, compared to an external temperature sensor (not shown) installed near the air inlet of the indoor unit 5, the measurement value of the intake air temperature sensor 58 of the indoor unit 2 increases to a greater extent when the compressor 21 is stopped. In contrast, the measurement values ​​of the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57 are equivalent to those of the external temperature sensor when the compressor 21 is stopped, and are considered to better reflect the indoor temperature.

[0099] FIG. 7 shows an example of the measured values ​​of the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57 when the indoor unit 5 is stopped and when the compressor 21 is operating.

[0100] 7, even when the indoor unit 5 is stopped, the measured values ​​of the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57 approach the indoor temperature over time, even during the time period when the compressor 21 is operating. During cooling operation, the valve closes when the indoor unit 5 is stopped, and the refrigerant stagnating on the indoor unit 5 side exchanges heat with the indoor air, so over time the measured values ​​reach the indoor temperature.

[0101] In this indoor temperature estimation method, when the refrigeration cycle device 1 is stopped, the indoor temperature can be estimated by reflecting the indoor temperature in the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57.

[0102] (4-2) In the indoor temperature estimation method using the indoor temperature estimation system 101 of this embodiment, the indoor temperature from a predetermined time onward is estimated based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 or the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 of the indoor unit 5.

[0103] This indoor temperature estimation method makes it possible to estimate the indoor temperature from a predetermined time onward without installing an additional sensor.

[0104] (4-3) In the indoor temperature estimation method by the indoor temperature estimation system 101 of this embodiment, the predetermined time includes a first time. The first time is the time when the refrigerant circuit 10 of the refrigeration cycle apparatus 1 is pressure-equalized after the outdoor unit 2 is stopped.

[0105] This indoor temperature estimation method makes it possible to estimate the indoor temperature after the indoor unit 5 has stopped and the refrigerant circuit 10 has been pressure equalized.

[0106] (4-4) In the indoor temperature estimation method by the indoor temperature estimation system 101 of this embodiment, when the difference in absolute value between the condensing temperature and the evaporating temperature is equal to or less than a predetermined value, it is determined that the refrigerant circuit 10 is pressure-equalized. The condensing temperature is calculated from the discharge pressure Hp detected by the discharge pressure sensor 43 of the compressor 21 of the outdoor unit 2. The evaporating temperature is calculated from the suction pressure Lp detected by the suction pressure sensor 41 of the compressor 21 of the outdoor unit 2.

[0107] In this indoor temperature estimation method, the discharge pressure Hp and suction pressure Lp of the compressor 21 can be used to determine whether the pressure in the refrigerant circuit is equal.

[0108] (4-5) The indoor temperature estimation system 101 of this embodiment is a system that estimates the indoor temperature when the operation of the refrigeration cycle apparatus 1 is stopped. The indoor temperature estimation system 101 includes a refrigerant circuit 10 and an estimation unit 115. The refrigerant circuit 10 connects the outdoor unit 2 and the indoor unit 5 via a liquid refrigerant communication pipe 6 and a gas refrigerant communication pipe 7. The estimation unit 115 estimates the indoor temperature after the indoor unit 5 is stopped. The indoor unit 5 includes an indoor heat exchanger inlet temperature sensor 56 and an indoor heat exchanger outlet temperature sensor 57. The estimation unit 115 estimates the indoor temperature based on a refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and a refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57.

[0109] In this indoor temperature estimation system 101, when the refrigeration cycle device 1 is stopped, the indoor temperature can be estimated by reflecting the indoor temperature in the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57.

[0110] (4-6) The indoor temperature estimation system 101 of this embodiment further includes a determination unit 114 that determines whether a predetermined time has elapsed.

[0111] In this indoor temperature estimation system 101, the determination unit 114 determines whether a predetermined time has elapsed, so that the indoor temperature can be estimated at an appropriate timing after the indoor unit 5 has stopped.

[0112] (5) Modifications (5-1) Modification 1A In the present embodiment, the predetermined time after the indoor unit 5 has stopped is the time when the refrigerant circuit 10 has been pressure equalized. However, the predetermined time may be the time when a certain time has elapsed (second time) after the indoor unit 5 has stopped. In Modification 1A, the predetermined time is the time when five hours have elapsed after the indoor unit 5 has stopped, but the certain time after the indoor unit 5 has stopped is not limited to five hours.

[0113] An example of processing by the indoor temperature estimation system 101 in Modification 1A will be described using the flowchart of FIG. 8 . FIG. 8 illustrates an example of estimating the indoor temperature when cooling operation is stopped. When cooling operation is stopped, even if the outdoor unit 2 is operating, if the indoor unit 5 is stopped, refrigerant does not flow into the piping on the indoor unit 5 side. Due to the influence of stagnant refrigerant, the refrigerant temperature TH1 (liquid pipe temperature) detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 (gas pipe temperature) detected by the indoor heat exchanger outlet temperature sensor 57 approach the indoor temperature over time. Furthermore, when the heating operation of the one-system, one-indoor-unit air conditioner 1 (see FIG. 2 ) is stopped, the outdoor unit 2 also stops when the indoor unit 5 is stopped, and the refrigerant temperatures TH1 and TH2 of the indoor unit 5 approach the indoor temperature over time, just as when cooling operation is stopped. Therefore, even when heating operation of the one-system, one-indoor-unit air conditioner 1 is stopped, the indoor temperature can be estimated in the same way as when cooling operation is stopped.

[0114] Step S1 of stopping the operation of the indoor unit 5, step S6 of acquiring the liquid side temperature of the indoor unit 5, and step S7 of acquiring the gas side temperature of the indoor unit 5 are the same as the processing of this embodiment shown in Figure 5, so detailed explanations will be omitted.

[0115] In step S11, the determination unit 114 determines whether five hours have passed since the indoor unit 5 was stopped. If it is determined that five hours have passed since the indoor unit 5 was stopped (Yes in step S11), the process proceeds to step S6.

[0116] In step S8, the estimation unit 115 estimates the indoor temperature based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 obtained in step S6 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 obtained in step S7. In Modification 1A, the estimator 115 estimates the indoor temperature after five hours have elapsed since the indoor unit 5 was stopped to be the average of the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57. The estimator 115 may estimate the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 or the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 to be the indoor temperature after five hours have elapsed since the indoor unit 5 was stopped.

[0117] In variant example 1A, if the difference between the evaporating temperature and the condensing temperature does not fall below the threshold value due to the influence of the indoor unit 5 operating in another room, but the time after the indoor unit 5 has stopped and a certain amount of time has elapsed is shorter than the time after the indoor unit has stopped and the difference between the evaporating temperature and the condensing temperature of the outdoor unit 2 falls below the threshold value (refrigerant pressure equalization time), it is determined that the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57 on the indoor unit 5 side reflect the room temperature after the certain amount of time has elapsed since the indoor unit 5 stopped, and the indoor temperature can be estimated by calculating a representative indoor temperature using the indoor heat exchanger inlet temperature sensor 56 and the indoor heat exchanger outlet temperature sensor 57.

[0118] In Modification 1A, it is possible to estimate the indoor temperature after a certain time has elapsed since the indoor unit 5 was stopped.

[0119] In addition, when multiple indoor units are connected to one outdoor unit (for example, when indoor units of the same system are installed in multiple spaces), if even one indoor unit is in heating operation, high-temperature refrigerant flows through the stopped indoor unit. Therefore, after the outdoor unit is stopped, the refrigerant temperature TH1 (liquid pipe temperature) detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 (gas pipe temperature) detected by the indoor heat exchanger outlet temperature sensor 57 gradually approach the indoor temperature due to the influence of stagnant refrigerant in the indoor unit. Therefore, the indoor temperature is estimated five hours after the outdoor unit is stopped. Figure 9 shows an example of estimating the indoor temperature when heating operation is stopped in an air conditioner (not shown) with multiple indoor units 5 connected to one outdoor unit 2.

[0120] Step S2 of stopping the operation of the outdoor unit 2, step S6 of acquiring the liquid side temperature of the indoor unit 5, and step S7 of acquiring the gas side temperature of the indoor unit 5 are the same as the processing of this embodiment shown in Figure 5, so detailed explanations will be omitted.

[0121] In step S12, the determination unit 114 determines whether five hours have passed since the outdoor unit 2 was stopped. If it is determined that five hours have passed since the outdoor unit 2 was stopped (Yes in step S12), the process proceeds to step S6.

[0122] In step S8, the estimation unit 115 estimates the indoor temperature based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 obtained in step S6 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 obtained in step S7.

[0123] (5-2) Variation 1B The estimation unit 115 may estimate the indoor temperature between the time the indoor unit 5 is stopped and the time (first time) when the refrigerant circuit 10 is pressure-equalized after the outdoor unit 2 is stopped by adding a correction value to the intake air temperature TH3 detected by the intake air temperature sensor 58 of the indoor unit 5 at the time the indoor unit 5 is stopped.

[0124] An example of the indoor temperature from the indoor unit stop time to the refrigerant pressure equalization time is shown in Fig. 10. Fig. 10 shows an example of estimating the indoor temperature when the air conditioning operation of the air conditioner 1 is stopped.

[0125] When the operation of the indoor unit 5 is stopped, the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 of the indoor unit 5 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 increase and become constant over time. Therefore, as shown in Figure 4, the average value of the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 becomes constant over time after the operation of the indoor unit 5 is stopped.

[0126] Thereafter, when the operation of the outdoor unit 2 is stopped, the condensing temperature calculated from the discharge pressure Hp of the compressor 21 of the outdoor unit 2 decreases, and the temperature change becomes smaller as time passes. Also, when the operation of the outdoor unit 2 is stopped, the evaporating temperature calculated from the suction pressure Lp of the compressor 21 of the outdoor unit 2 increases, and the temperature change becomes smaller as time passes.

[0127] The time when the absolute difference between the condensing temperature and the evaporating temperature becomes 1° C. or less is defined as the refrigerant pressure equalization time (see FIG. 4).

[0128] In variant example 1B, between the time when the indoor unit 5 is stopped and the time when the refrigerant pressure is equalized, the estimation unit 115 estimates the indoor temperature by adding a correction value to the intake air temperature TH3 at the time when the indoor unit 5 is stopped.

[0129] An example of processing by the indoor temperature estimation system 101 of Modification 1B will be described with reference to the flowchart of Fig. 11. Fig. 11 shows an example of estimating the indoor temperature when cooling operation is stopped, but the indoor temperature during heating operation may also be estimated.

[0130] Step S1 of stopping operation of the indoor unit 5, step S2 of stopping operation of the indoor unit 2, step S3 of acquiring the discharge pressure Hp on the outdoor unit 2 side, step S4 of acquiring the suction pressure Lp on the outdoor unit 2 side, and step S5 of determining whether it is time to equalize the refrigerant pressure are the same as the processing of this embodiment shown in Figure 5, so detailed explanations will be omitted.

[0131] In step S1, the indoor unit 5 of the air conditioner 1 that was performing cooling operation stops operation.

[0132] In step S21, the acquisition unit 111 acquires the intake air temperature TH3 detected by the intake air temperature sensor 58 of the indoor unit 5.

[0133] In step S22, the estimation unit 115 adds a correction value to the intake air temperature TH3 acquired in step S21. In step S22, the correction value used when the cooling operation is stopped (cooling correction value) is 2 [°C] / 5 [hours] x elapsed time since the indoor unit was stopped [hours], and the upper limit of the cooling correction value is set to, but is not limited to, 2°C. In step S22, the estimation unit 115 estimates the indoor temperature by adding the correction value to the intake air temperature TH3 until the refrigerant pressure equalization time arrives (Yes in step S5).

[0134] When the air conditioner 1 that was performing heating operation is stopped, in step S22, a heating correction value is added to the intake air temperature TH3 acquired in step S21. The heating correction value is -2 [°C] / 5 [hours] x elapsed time since the indoor unit was stopped [hours], and the lower limit of the heating correction value is -2°C, but is not limited to this.

[0135] The process of Modification 1B is performed when the indoor unit 5 starts operating again before the refrigerant pressure equalization time.

[0136] The estimation unit 115 may estimate the indoor temperature between the time the indoor unit 5 is stopped and the time a certain time has elapsed after the indoor unit 5 is stopped (second time) by adding a correction value to the intake air temperature TH3 detected by the intake air temperature sensor 58 of the indoor unit 5 at the time the indoor unit 5 is stopped. The certain time is, for example, five hours after the indoor unit 5 is stopped. When estimating the indoor temperature between the time the indoor unit 5 is stopped and the time a certain time has elapsed after the indoor unit 5 is stopped, it is preferable to estimate the indoor temperature from the time a certain time has elapsed after the indoor unit 5 is stopped when operations other than heating operation are stopped.

[0137] The processing of Modification 1B is performed when the indoor unit 5 starts operating again before the second time, for example.

[0138] In variant example 1B, by correcting the intake air temperature TH3 of the indoor unit 5, it is possible to estimate the indoor temperature between the time the indoor unit 5 is stopped and the time the refrigerant pressure is equalized, or the time a certain amount of time has passed since the indoor unit 5 was stopped.

[0139] (5-3) Modification 1C The estimation unit 115 may perform linear interpolation to estimate the indoor temperature between the stop time of the indoor unit 5 and the time when the refrigerant circuit 10 is pressure equalized, or the time when a certain time has elapsed after the stop time of the indoor unit 5. Furthermore, the estimation method is not limited to linear interpolation.

[0140] If the starting point is the time when the indoor unit 5 is stopped and the first end point is the time when the refrigerant circuit 10 is pressure equalized (first time), the estimation unit 115 estimates the indoor temperature at the time between the starting point and the first end point using a predetermined function, using the intake air temperature TH3 detected by the intake air temperature sensor 58 of the indoor unit 5 at the starting point and a first calculated value calculated based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 at the first end point.

[0141] The processing by the indoor temperature estimation system 101 of Modification 1C will be described using the flowchart in Fig. 12. Fig. 12 shows an example in which the indoor temperature is estimated when the air conditioner 1 is not in cooling operation, but the indoor temperature may be estimated during heating operation.

[0142] Step S1 of stopping operation of the indoor unit 5, step S2 of stopping operation of the indoor unit 2, step S3 of acquiring the discharge pressure Hp on the outdoor unit 2 side, step S4 of acquiring the suction pressure Lp on the outdoor unit 2 side, step S5 of determining whether it is time to equalize the refrigerant pressure, step S6 of acquiring the liquid side temperature of the indoor unit 5, and step S7 of acquiring the gas side temperature of the indoor unit 5 are the same as the processing of this embodiment shown in Figure 5, so detailed explanations will be omitted.

[0143] In step S31, the acquisition unit 111 acquires the intake air temperature TH3 detected by the intake air temperature sensor 58. In step S31, the acquisition unit 111 acquires the intake air temperature TH3 at the time when the indoor unit 5 of the air conditioner 1 that was performing cooling operation in step S1 was stopped.

[0144] In step S32, estimation unit 115 estimates the indoor temperature at the refrigerant pressure equalization time. In variation 1C, estimation unit 115 estimates the indoor temperature at the refrigerant pressure equalization time as the average value of refrigerant temperature TH1 detected by indoor heat exchanger inlet temperature sensor 56 and refrigerant temperature TH2 detected by indoor heat exchanger outlet temperature sensor 57.

[0145] In step S33, the estimation unit 115 estimates the indoor temperature at a time between the time the indoor unit 5 stopped and the refrigerant pressure equalization time. In step S33, the estimation unit 115 estimates the indoor temperature at a time between the time the indoor unit 5 stopped and the refrigerant pressure equalization time by linearly interpolating the intake air temperature TH3 at the indoor unit stopped time acquired in step S31 and the indoor temperature at the refrigerant pressure equalization time acquired in step S32. This makes it possible to estimate the indoor temperature between the time the indoor unit 2 stopped and the time the refrigerant circuit 10 was pressure equalized.

[0146] Furthermore, when the time when the indoor unit 5 is stopped is taken as the start point and the time (second time) a certain time has elapsed since the indoor unit 5 was stopped is taken as the second end point, the estimation unit 115 may estimate the indoor temperature at a time between the start point and the second end point using a predetermined function, using the intake air temperature TH3 detected by the intake air temperature sensor 58 of the indoor unit 5 at the start point and a second calculated value calculated based on the refrigerant temperature TH1 detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 detected by the indoor heat exchanger outlet temperature sensor 57 at the second end point. When estimating the indoor temperature between the time when the indoor unit 5 is stopped and the time a certain time has elapsed since the indoor unit 5 was stopped, it is preferable to estimate the indoor temperature after operations other than heating operation are stopped. This makes it possible to estimate the indoor temperature between the time when the indoor unit 5 is stopped and the time a certain time has elapsed since the indoor unit 5 was stopped.

[0147] In addition, the estimation unit 115 may predict the indoor temperature at the first end point or the second end point before the time when the refrigerant circuit 10 is pressure-equalized (first end point) or before a certain time has elapsed after the indoor unit 5 has stopped (second end point), and predict the indoor temperature before the first end point or the second end point by linear interpolation or a predetermined function.

[0148] An example of predicting the first end point will be described. The refrigerant pressure-equalizing time is the time when the difference between the evaporation temperature and the condensation temperature becomes 1°C or less. After the outdoor unit 2 is shut down, the time when the difference between the evaporation temperature and the condensation temperature Δt becomes 1°C or less and the average value of the refrigerant temperature TH1 (indoor liquid pipe temperature) detected by the indoor heat exchanger inlet temperature sensor 56 and the refrigerant temperature TH2 (indoor gas pipe temperature) detected by the indoor heat exchanger outlet temperature sensor 57 are estimated based on the transition of the difference between the evaporation temperature and the condensation temperature Δt over a fixed time period and the transition of the average value of the refrigerant temperature TH1 and the refrigerant temperature TH2 at that time. These are then used to estimate the indoor temperature between the indoor temperature when the outdoor unit 2 was shut down and the first end point. The indoor temperature is predicted using linear interpolation or a predetermined function.

[0149] Next, an example of predicting the second end point will be described. When cooling operation is stopped, immediately after the indoor unit 5 is shut down, the refrigerant temperatures TH1 and TH2 on the indoor unit 5 side approach the room temperature over time. Immediately after the indoor unit 5 is shut down, the rate of change per unit time in the refrigerant temperatures TH1 and TH2 is large. However, as time passes and the refrigerant temperatures approach the room temperature, the rate of change becomes smaller. Therefore, based on the change Δt in the refrigerant temperatures TH1 and TH2 over a fixed time period and the change in the average values ​​of the refrigerant temperatures TH1 and TH2, the time when the average value of the refrigerant temperatures TH1 and TH2 becomes equal to the room temperature (the time when the change Δt in the refrigerant temperatures TH1 and TH2 becomes equal to or less than a predetermined value) and the average value of the refrigerant temperatures TH1 and TH2 at that time are estimated and set as the second end point. Starting from the room temperature when the indoor unit 5 is shut down, the indoor temperature in the section between the starting point and the second end point is predicted using linear interpolation or a predetermined function.

[0150] (5-4) Modification 1D When two or more indoor units are installed in an indoor space, the representative indoor temperature of the indoor space may be estimated using the indoor temperatures estimated by each indoor unit.

[0151] An example in which four indoor units 5a to 5d are installed in an indoor space is shown in Figure 13. When indoor units 5a to 5d are installed in the indoor space as shown in Figure 13, the representative indoor temperature of the indoor space is estimated using the indoor temperatures estimated by the indoor units 5a to 5d. This makes it possible to estimate the representative indoor temperature even when multiple indoor units are installed in the indoor space.

[0152] (5-5) Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure as defined in the claims.

[0153] REFRIGERATION CYCLE DEVICE 1: Air conditioner (refrigeration cycle device) 2: Outdoor unit 5, 5a to 5d: Indoor units 6: Liquid refrigerant connection pipe (connection piping) 7: Gas refrigerant connection pipe (connection piping) 8: Control unit 10: Refrigerant circuit 21: Compressor 22: Compressor motor 23: Switching mechanism 24: Outdoor heat exchanger 25: Expansion valve 26: Outdoor liquid refrigerant pipe 27: Suction pipe 28: Accumulator 29: Discharge pipe 30: First outdoor gas refrigerant pipe 31: Second outdoor gas refrigerant pipe 32: Liquid side shut-off valve 33: Gas side shut-off valve 34: Outdoor fan 41: Suction pressure sensor 42: Suction temperature sensor 43: Discharge pressure sensor 44: Discharge temperature sensor 52: Indoor heat exchanger 53: Indoor liquid refrigerant pipe 54 : Indoor gas refrigerant pipe 55 : Indoor fan 56 : Indoor heat exchanger inlet temperature sensor 57 : Indoor heat exchanger outlet temperature sensor 58 : Intake air temperature sensor 101 : Indoor temperature estimation system 110 : Estimation device 111 : Acquisition unit 112 : Storage unit 113 : Control unit 114 : Determination unit 115 : Estimation unit

[0154] Japanese Patent Application Publication No. 11-351637

Claims

1. A method for estimating an indoor temperature when a refrigeration cycle device (1) is stopped, comprising: estimating the indoor temperature based on a refrigerant temperature detected by a temperature sensor (56, 57) of an indoor unit after an outdoor unit (2) or an indoor unit (5, 5a-5d) has stopped.

2. The indoor temperature estimation method according to claim 1, wherein the indoor temperature from a predetermined time onward is estimated based on the refrigerant temperature (TH1) detected by the indoor heat exchanger inlet temperature sensor (56) of the indoor unit or the refrigerant temperature (TH2) detected by the indoor heat exchanger outlet temperature sensor (57) of the indoor unit.

3. The indoor temperature estimation method according to claim 2, wherein the predetermined time includes a first time, and the first time is the time when the refrigerant circuit (10) of the refrigeration cycle device is pressure-equalized after the outdoor unit is stopped.

4. The indoor temperature estimation method according to claim 3, wherein the refrigerant circuit is determined to be pressure-equalized when the difference in absolute value between the condensation temperature calculated from the discharge pressure (Hp) detected by the discharge pressure sensor (43) of the compressor of the outdoor unit and the evaporation temperature calculated from the suction pressure (Lp) detected by the suction pressure sensor (41) of the compressor of the outdoor unit is less than a predetermined value, or when the difference in absolute value between the discharge pressure and the suction pressure is less than a predetermined value.

5. The indoor temperature estimation method according to claim 2, wherein the predetermined time includes a second time, and the second time is a time when a certain time has elapsed after the indoor unit has stopped.

6. An indoor temperature estimation method as described in claim 3 or 4, wherein the indoor temperature between the stop time of the indoor unit and the first time is estimated by adding a correction value to the intake air temperature (TH3) detected by the intake air temperature sensor (58) of the indoor unit at the stop time of the indoor unit.

7. The indoor temperature estimation method according to claim 5, wherein the indoor temperature between the stop time of the indoor unit and the second time is estimated by adding a correction value to the intake air temperature detected by the intake air temperature sensor of the indoor unit at the stop time of the indoor unit.

8. An indoor temperature estimation method as described in claim 3 or 4, wherein the indoor temperature at a time between the start point and the first end point is estimated using a predetermined function, with the stop time of the indoor unit as a start point and the first time as a first end point, using a first calculated value calculated based on the intake air temperature detected by the intake air temperature sensor of the indoor unit at the start point, and the refrigerant temperature detected by the indoor heat exchanger inlet temperature sensor and the refrigerant temperature detected by the indoor heat exchanger outlet temperature sensor at the first end point.

9. The indoor temperature estimation method described in claim 5, wherein the indoor temperature at a time between the start point and the second end point is estimated using a predetermined function, using the intake air temperature detected by the intake air temperature sensor of the indoor unit at the start point and the second time as a second end point, and a second calculated value calculated based on the refrigerant temperature detected by the indoor heat exchanger inlet temperature sensor and the refrigerant temperature detected by the indoor heat exchanger outlet temperature sensor at the two end points.

10. An indoor temperature estimation method according to any one of claims 1 to 9, wherein in an indoor space in which two or more indoor units are installed, a representative indoor temperature of the indoor space is estimated using the indoor temperatures estimated by each indoor unit.

11. A system for estimating an indoor temperature when a refrigeration cycle device (1) stops operating, comprising: a refrigerant circuit (10) in which an outdoor unit (2) and indoor units (5, 5a-5d) are connected by connecting pipes (6, 7); and an estimation unit (115) that estimates the indoor temperature after the outdoor unit or the indoor unit stops operating, wherein the indoor units have temperature sensors (56, 57) that detect refrigerant temperatures, and the estimation unit estimates the indoor temperature based on the refrigerant temperatures detected by the temperature sensors.

12. The indoor temperature estimation system according to claim 11, further comprising a determination unit (114) that determines whether a predetermined time has elapsed.

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