A refrigerant leakage determination method includes the following steps. A refrigerant circuit formed by connecting a heat source unit and a utilization unit by a connection pipe is filled with a refrigerant of a first filling amount smaller than a target filling amount. Then, a first trial operation of circulating the refrigerant of the first filling amount in the refrigerant circuit is performed, and first trial operation data is acquired. Then, after the step of acquiring, the refrigerant circuit is filled with the refrigerant until the target filling amount is reached. Thereafter, normal operation data is acquired during a normal operation after filling the refrigerant circuit with the target filling amount. Subsequently, the presence or absence of a refrigerant leakage from the refrigerant circuit is determined on the basis of the normal operation data and the first trial operation data.
Legal claims defining the scope of protection, as filed with the USPTO.
. A refrigerant leakage determination method, comprising:
. The refrigerant leakage determination method according to, wherein the normal operation data and the first trial operation data include data of an opening degree of an expansion valve of the heat utilizer, a degree of superheating at an outlet of an evaporator of the heat source or the heat utilizer, a degree of subcooling at an outlet of a condenser of the heat source or the heat utilizer, or a liquid pipe temperature detected at a liquid pipe outlet of the heat utilizer.
. The refrigerant leakage determination method according to, wherein the leak is determined to be present when the opening degree of the expansion valve of the heat utilizer during the normal operation increases so as to approach the opening degree of the expansion valve of the heat utilizer during the first trial operation.
. The refrigerant leakage determination method according to, wherein the first filling amount is 50% or more and less than 100% of the target filling amount.
. The refrigerant leakage determination method according to, further comprising:
. The refrigerant leakage determination method according to, wherein filling the refrigerant circuit with the refrigerant to the second filling amount is performed after acquiring the first trial operation data.
. The refrigerant leakage determination method according to, wherein:
. A refrigeration cycle apparatus, comprising:
. The refrigeration cycle apparatus according to, wherein the first trial operation data include data of an opening degree of an expansion valve of the heat utilizer, a degree of superheating at an outlet of an evaporator of the heat source or the heat utilizer, a degree of subcooling at an outlet of a condenser of the heat source or the heat utilizer, or a liquid pipe temperature detected at a liquid pipe outlet of the heat utilizer.
. The refrigeration cycle apparatus according to, wherein:
. The refrigeration cycle apparatus according to, wherein the first filling amount is 50% or more and less than 100% of the target filling amount.
. The refrigeration cycle apparatus according to, wherein the controller includes circuitry that is configured to acquire second trial operation data by performing a second trial operation of circulating a second filling amount of the refrigerant in the refrigerant circuit, the second filling amount being larger than the first filling amount and smaller than the target filling amount.
. The refrigeration cycle apparatus according to, wherein circulating the second filling amount of the refrigerant in the refrigerant circuit is performed after acquiring the first trial operation data.
. The refrigeration cycle apparatus according to, wherein:
Complete technical specification and implementation details from the patent document.
The present application is a continuation of international application no. PCT/JP2023/045715, filed Dec. 20, 2023, which claims priority to Japanese patent application JP 2022-208822, filed Dec. 26, 2022, the entire contents of each are incorporated herein by reference.
Embodiments relate to a refrigerant leakage determination method and a refrigeration cycle apparatus.
Patent Literature 1 (WO 2015/004747 A) discloses a refrigeration cycle apparatus including a refrigerant circuit configured to circulate a refrigerant through a compressor, a condenser, an expansion valve, and an evaporator, the compressor and the condenser being connected by a first extension pipe, and the expansion valve and the evaporator being connected by a second extension pipe, a detector that detects an operation state amount of the refrigerant circuit, and a control unit that performs a refrigerant leakage detection operation by calculating a refrigerant amount inside the refrigerant circuit on the basis of the operation state amount detected by the detector and performing refrigerant leakage detection by comparing the calculated refrigerant amount with a reference refrigerant amount, in which the control unit controls a dryness of the refrigerant at an outlet of the second extension pipe to be 0.1 or more and 0.7 or less during the refrigerant leakage detection operation.
A refrigerant leakage determination method according to a first aspect includes the following steps. A refrigerant circuit formed by connecting a heat source unit and a utilization unit by a connection pipe is filled with a refrigerant of a first filling amount smaller than a target filling amount. A first trial operation of circulating the refrigerant of the first filling amount in the refrigerant circuit is performed, and first trial operation data is acquired. After the step of acquiring, the refrigerant circuit is filled with the refrigerant until the target filling amount is reached. Normal operation data is acquired during a normal operation after filling the refrigerant circuit with the target filling amount. The presence or absence of a refrigerant leakage from the refrigerant circuit is determined on the basis of the normal operation data and the first trial operation data.
As shown in, a management systemof a refrigeration cycle apparatusis a device for managing the refrigeration cycle apparatus. The management systemof the refrigeration cycle apparatusis a system that determines presence or absence of a refrigerant leakage from the refrigeration cycle apparatusand notifies a user when it is determined that there is a refrigerant leakage. The user includes a person who uses the refrigeration cycle apparatusand a person who manages the refrigeration cycle apparatus.
The management systemincludes the refrigeration cycle apparatus, a server, and an information device. The serveris connected to the refrigeration cycle apparatus. The information deviceis connected to the server. A description will be given of each configuration included in the management system.
The refrigeration cycle apparatusis an apparatus that processes a thermal load of a target space by performing a vapor compression refrigeration cycle, and is, for example, an air conditioner that conditions air in the target space. As shown in, the refrigeration cycle apparatusincludes one heat source unit(i.e., heat source), a plurality of utilization units(i.e., heat utilizer), connection pipesandconnecting heat source unitand the plurality of utilization units, and a remote controller. In the present embodiment, the heat source unitand the utilization unitare communicably connected via a transmission lineshown in.
A vapor compression refrigerant circuitof the refrigeration cycle apparatusis configured by connecting the heat source unitand the utilization unitvia the connection pipesand. The refrigerant circuitis filled with a refrigerant for a vapor compression refrigeration cycle. The refrigerant to fill the refrigerant circuitis not limited, and for example, the refrigerant circuitis filled with R32 or the like. The refrigerant circuitis filled with refrigerating machine oil in together with the refrigerant.
As shown in, the heat source unitis connected to the utilization unitvia the connection pipesand, and constitutes a part of the refrigerant circuit. The heat source unitmainly includes a compressor, a four-way switching valve, a first heat exchanger, a first expansion valve, a first fan, a receiver, a gas-side shutoff valve, a liquid-side shutoff valve, and first to seventh refrigerant pipesto.
The compressoris a device that compresses a low-pressure refrigerant in the refrigeration cycle to a high pressure. The compressorused herein can be a closed compressor in which a rotary type, scroll type, or other positive-displacement compression element is driven to rotate by a compressor motor. The compressor motor is for changing a capacity, and an operating frequency can be controlled by an inverter. The seventh refrigerant pipeas a suction pipe is connected to a suction side of the compressor. The first refrigerant pipeas a discharge pipe is connected to a discharge side of the compressor.
The four-way switching valveis a valve whose flow path is switched by movement control of a valve body (not shown), and switches the refrigerant circuitbetween a cooling connection state and a heating connection state. Specifically, in the cooling connection state, the four-way switching valveis switched to a state of connecting the first refrigerant pipeconnected to the discharge side of the compressorand the second refrigerant pipeconnected to the first heat exchangerwhile connecting the seventh refrigerant pipe, the receiver, the sixth refrigerant pipeconnected to the suction side of the compressorand the fifth refrigerant pipeconnected to the gas-side shutoff valve. In the heating connection state, the four-way switching valveis switched to a state of connecting the first refrigerant pipeconnected to the discharge side of the compressorand the fifth refrigerant pipeconnected to the gas-side shutoff valvewhile connecting the seventh refrigerant pipe, the receiver, the sixth refrigerant pipeconnected to the suction side of the compressorand the second refrigerant pipeconnected to the first heat exchanger.
The first heat exchangerfunctions as a condenser for the high-pressure refrigerant in the refrigeration cycle during a cooling operation, and functions as an evaporator for the low-pressure refrigerant in the refrigeration cycle during a heating operation. A gas-side end of the first heat exchangeris connected to the four-way switching valvevia the second refrigerant pipe. A liquid-side end of the first heat exchangeris connected to the first expansion valvevia the third refrigerant pipe.
The first expansion valveis provided between a liquid-side outlet of the first heat exchangerand the liquid-side shutoff valvein the refrigerant circuit. The first expansion valveis an electric expansion valve having an adjustable valve opening degree by movement control of a valve body (not shown) with respect to a valve seat (not shown). The first expansion valveand the liquid-side shutoff valveare connected via the fourth refrigerant pipe.
The first fansucks outdoor air into the heat source unit, causes the first heat exchangerto exchange heat with the refrigerant, and then generates an air flow to be discharged to the outside. The first fanis driven to rotate by a fan motor.
The receiveris provided between the suction side of the compressorand one of connecting ports of the four-way switching valve, and is a refrigerant container capable of storing surplus refrigerant in the refrigerant circuitas liquid refrigerant. An inlet side of the receiveris connected to the four-way switching valvevia the sixth refrigerant pipe. An outlet side of the receiveris connected to the suction side of the compressorvia the seventh refrigerant pipe.
The liquid-side shutoff valveis a manual valve disposed at a connecting portion of the heat source unitwith the liquid-side connection pipe. The gas-side shutoff valveis a manual valve disposed at a connecting portion of the heat source unitwith the gas-side connection pipe.
The heat source unitis provided with a discharge pressure sensor, a discharge temperature sensor, a suction pressure sensor, a suction temperature sensor, a liquid-side temperature sensor, an outside air temperature sensor, and the like. The discharge pressure sensordetects the pressure of the refrigerant flowing through the first refrigerant pipe, which is a discharge pipe connecting the discharge side of the compressorand one of the connecting ports of the four-way switching valve. The discharge temperature sensordetects the temperature of the refrigerant flowing through the first refrigerant pipeas a discharge pipe. The suction pressure sensordetects the pressure of the refrigerant flowing through the seventh refrigerant pipe, which is a suction pipe connecting the suction side of the compressorand the receiver. The suction temperature sensordetects the temperature of the refrigerant flowing through seventh refrigerant pipeas a suction pipe. The liquid-side temperature sensordetects the temperature of the refrigerant flowing through the liquid-side outlet of the first heat exchangeropposite to the side to which the four-way switching valveis connected. The outside air temperature sensordetects the temperature of outdoor air before the outdoor air passes through the first heat exchanger. Each of these sensors is electrically connected to a first control unit(i.e., first controller, described later), and transmits a detection signal to the first control unit
As shown in, the heat source unitincludes a first communication unit, a first input unit, the first control unit, and a first storage
The first communication unitis an interface for communicating with the utilization unit. The first communication unitis also an interface for communicating with the server.
The first input unitis a button for receiving a command to execute a first trial operation from an operator. Here, the first input unitincludes a button for receiving a command to execute the first trial operation and a button for receiving a command to execute a final trial operation. When the command to execute the first trial operation or the final trial operation is received by the first input unit, the first trial operation or the final trial operation is executed by the first control unit, and a plurality of trial operation data (described later) is detected.
The first control unitis a calculation processing device such as a central processing unit (CPU). The first control unitreads and executes a program stored in the first storage
The first control unitcontrols (e.g., includes circuitry configured to control) an operation of each part constituting the heat source unit. The first control unitcan exchange a control signal with a second control unitof each utilization unitvia the transmission line. Here, the first control unitconnected to the transmission lineand each of the second control unitscooperate to control the entire operation of the refrigeration cycle apparatus. In other words, the first control unitcontrols (e.g., includes circuitry configured to control) the operation of the refrigerant circuitin cooperation with the second control unit, e.g., the first control unitand the second control unittogether may be a controller.
Specifically, the first control unitoperates each unit constituting the heat source unitin accordance with a control command to start, stop, set a temperature, set a humidity, set an air volume, set an air direction, or set an operating mode of the utilization unit. More specifically, the first control unitgenerates a control command for adjusting a frequency of the compressor, a number of rotations of the first fan, the opening degree of the first expansion valve, and the like.
Furthermore, the first control unitacquires first trial operation data by performing the first trial operation of circulating the refrigerant of a first filling amount smaller than a target filling amount (100%) in the refrigerant circuit. The target filling amount is a required refrigerant filling amount described in an installation instruction. The target filling amount is an amount of the refrigerant circulating in the refrigerant circuitwhen a normal operation such as the cooling operation or the heating operation is performed. The first filling amount is, for example, 50% or more and less than 100% of the target filling amount, and is set to 70% of the target filling amount in the present embodiment.
Specifically, when the first input unitreceives the command to execute the first trial operation, the first control unitoperates each unit constituting the heat source unitto execute the first trial operation, and sends a command to the second control unitof the utilization unitto operate each part constituting the utilization unit. Then, the first control unitacquires the first trial operation data during the first trial operation. The first trial operation data is, for example, an opening degree of the second expansion valveof each utilization unit. Then, the first control unitstores the acquired first trial operation data in the first storage
The first control unitacquires final trial operation data by performing the final trial operation of circulating the refrigerant of the target filling amount in the refrigerant circuit. Specifically, when the first input unitreceives the command to execute the final trial operation, the first control unitoperates each unit constituting the heat source unitto execute the final trial operation, and sends a command to the second control unitof the utilization unitto operate each part constituting the utilization unit. Then, the first control unitacquires the final trial operation data during the final trial operation. The final trial operation data is, for example, the opening degree of the second expansion valveof each utilization unit. Then, the acquired final trial operation data is stored in the first storage
In this manner, the first control unithas a plurality of trial operation modes. In the present embodiment, the first control unithas two modes, namely, the first trial operation of circulating the refrigerant of the first filling amount smaller than the target filling amount, and the final trial operation of circulating the refrigerant of the target filling amount.
Furthermore, the first control unitacquires normal operation data during the normal operation after filling the refrigerant circuitwith the target filling amount, and determines the presence or absence of a refrigerant leakage from the refrigerant circuiton the basis of the normal operation data and the first trial operation data. In the present embodiment, the first control unitdetermines the presence or absence of a refrigerant leakage from the refrigerant circuiton the basis of the normal operation data, the first trial operation data, and the final trial operation data. Here, in the normal operation, the first control unitcompares the normal operation data at the time when a condition similar to a condition of the first trial operation is satisfied with the first trial operation data, and when the normal operation data is similar to the first trial operation data, the first control unitdetermines that the refrigerant has leaked from the refrigerant circuit.
The first trial operation data and the final trial operation data acquired by the first control unitare, for example, data on the opening degree of each second expansion valveat the time when all of the plurality of utilization unitsperforms the cooling operation. The first control unitacquires the opening degree of each of the second expansion valvesas the normal operation data when all the utilization unitsperforms the cooling operation during the normal operation. The first control unitcompares the opening degree of each second expansion valveas the first trial operation data, the opening degree of each second expansion valveas the final trial operation data, and the opening degree of each second expansion valveas the normal operation data. Specifically, the presence or absence of a refrigerant leakage is determined by calculating how close the opening degree of each second expansion valveduring the normal operation is to the opening degree of each second expansion valveduring the first trial operation from the opening degree of each second expansion valveduring the final trial operation. Note that target evaporation temperatures in the first trial operation, the final trial operation, and the normal operation are the same.
The first storageincludes a ROM, a RAM, a hard disk, and the like. The first storagestores a program that can be read and executed by the first control unit. The first storagestores the first trial operation data, the final trial operation data, the normal operation data, and the like.
The utilization unitis installed on, for example, an indoor wall surface, a ceiling, or the like as the target space. The utilization unitis connected to the heat source unitvia the connection pipesand, and constitutes a part of the refrigerant circuit. In the refrigeration cycle apparatusaccording to the present embodiment, the plurality of utilization unitsis connected in parallel to one heat source unit. Since the utilization unitshave similar configurations, one utilization unitwill be described below.
The utilization unitincludes a second heat exchanger, an eighth refrigerant pipe, a ninth refrigerant pipe, a second fan, and the second expansion valve.
The second heat exchangerhas a liquid side connected to liquid-side connection pipevia the eighth refrigerant pipe, and a gas side end connected to the gas-side connection pipevia the ninth refrigerant pipe. The second heat exchangerfunctions as an evaporator for the low-pressure refrigerant in the refrigeration cycle during the cooling operation, and functions as a condenser for the high-pressure refrigerant in the refrigeration cycle during the heating operation.
The second fansucks indoor air into the utilization unit, causes the second heat exchangerto exchange heat with the refrigerant, and then generates an air flow to be discharged to the outside. The second fanis driven to rotate by a fan motor. The second fancan be driven with the set air volume received from the remote controller.
The second expansion valveis provided between a liquid-side inlet of the second heat exchangerand the liquid-side connection pipein the refrigerant circuit. The second expansion valveis an electric expansion valve having an adjustable valve opening degree by movement control of a valve body (not shown) with respect to a valve seat (not shown). The second expansion valveis provided corresponding to the liquid side of the second heat exchanger. The second expansion valveis an expansion mechanism that adjusts a flow rate of the refrigerant flowing through the second heat exchangerwhile decompressing the refrigerant.
The utilization unitis provided with a liquid-side heat exchange temperature sensor, an air temperature sensor, and the like. The liquid-side heat exchange temperature sensordetects the temperature of the refrigerant flowing through a liquid-refrigerant side inlet of the second heat exchanger. The air temperature sensordetects the temperature of indoor air before the indoor air passes through the second heat exchanger. Each of these sensors is electrically connected to the second control unit(described later), and transmits a detection signal to the second control unit.
The utilization unitincludes a second communication unitand the second control unit. The second communication unitis an interface for communicating with the heat source unit.
The second control unitincludes a microcomputer including a processor such as a central processing unit (CPU), a memory, and the like.
The utilization unitincludes the second control unitand the second communication unitthat control the operation of each part constituting the utilization unit. The second control unitreceives a control signal from the heat source unitvia the second communication unit, and operates each part constituting the utilization uniton the basis of the control signal. Specifically, the second control unitgenerates a control command for adjusting a number of rotations of the second fan, the opening degree of the second expansion valve, and the like.
The second control unittransmits data on an operation state such as an ON or OFF state and a suction temperature to the heat source unitvia the second communication unit.
The remote controllerthat receives an operation input to each utilization unitis separately attached to each utilization unit. The remote controllerincludes an input unit that receives a control command to each of the utilization units, and a display that displays an operation status of each of the utilization units. The operation status displayed on the display of the remote controllerincludes information indicating an operation state such as the cooling operation, the heating operation, and an inspection, and information such as a set temperature, an air volume, and an air flow direction.
The servershown inis connected to the refrigeration cycle apparatusvia a communication line either in a wired or wireless manner. The serverhas a function of monitoring and controlling the refrigeration cycle apparatus. The serveraccording to the present embodiment is constructed on a cloud.
When the first control unitdetermines that there is a refrigerant leakage, the server receives a notification of the leakage from the first control unitand notifies the user of the leakage. Here, when it is determined that there is a refrigerant leakage, the servernotifies the information deviceof the user of the leakage. The notification is performed by issuing a warning to the user by sound, light, display, or the like.
The information deviceis notified when the refrigeration cycle apparatusdetermines that there is a refrigerant leakage. The type of the information deviceis not limited, and is, for example, a smartphone, a wearable device, a personal computer, a tablet, or the like. Examples of the wearable device include a wristband-type device, a wristwatch-type device, or the like that is worn on an arm, a headband-type device, a glasses-type device, or the like that is worn on a head, and a cloth-type device, or the like that is worn on a body.
The refrigeration cycle apparatuscan execute at least a cooling operating mode and a heating operating mode as the normal operation. In the refrigeration cycle apparatusaccording to the present embodiment, the plurality of utilization unitscan perform the cooling operation or the heating operation individually.
In the refrigeration cycle apparatus, the first control unitand the second control unitdetermine whether the operation mode is the cooling operation mode or the heating operating mode on the basis of an instruction received from the remote controlleror the like, and execute the determined operating mode.
The cooling operation is performed by the first control unitand the second control unitreceiving a command of the cooling operation via the remote controller. The first control unitand the second control unitcontrol the operations of the compressor, the four-way switching valve, the first expansion valve, the first fan, the second fan, the second expansion valve, and the like as constituent devices of the heat source unitand the utilization unit.
In the cooling operation, the four-way switching valveis switched to a state such that the first heat exchangerfunctions as a refrigerant condenser and the second heat exchangerfunctions as a refrigerant evaporator (as shown by the solid lines of the four-way switching valvein).
In the refrigerant circuitin such a state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor, compressed to a high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressoris sent to the first heat exchangerthrough the four-way switching valve. The high-pressure refrigerant sent to the first heat exchangerexchanges heat with the outdoor air supplied by the first fanand condenses in the first heat exchanger. The high-pressure refrigerant having condensed in the first heat exchangeris sent to the first expansion valveand decompressed to a low pressure in the refrigeration cycle. The low-pressure refrigerant decompressed in the first expansion valveflows out of the heat source unitand is branched and sent to each utilization unitthrough the liquid-side connection pipe. The refrigerant sent to the utilization unitis decompressed to a low pressure in the refrigeration cycle by the second expansion valveand sent to the second heat exchanger. The low-pressure refrigerant sent to the second heat exchangerexchanges heat with the indoor air supplied by the second fanin the second heat exchangerand evaporates. As a result, the indoor air is cooled and blown to indoor. The low-pressure refrigerant having evaporated in the second heat exchangeris again sucked into the compressorthrough the gas-side connection pipe, the four-way switching valve, and the receiver. In this manner, in the cooling operation, the first control unitand the second control unitperform an operation of circulating the refrigerant sealed in the refrigerant circuitthrough the compressor, the first heat exchanger, the first expansion valve, the second expansion valve, and the second heat exchangerin that order.
During the cooling operation, the first control unitand the second control unitperform capacity control to control the capacity of the compressorsuch that an evaporation temperature of the refrigerant in the refrigerant circuitapproaches a predetermined target evaporation temperature. The capacity control of the compressoris performed by controlling the number of rotations (frequency) of the compressor motor. The evaporation temperature of the refrigerant is obtained by converting the suction pressure detected by the suction pressure sensorinto a saturation temperature of the refrigerant. The refrigerant evaporation temperature is a temperature obtained by converting the pressure (evaporation pressure of the refrigerant in the refrigerant circuit) representing the low-pressure refrigerant in the refrigeration cycle flowing from an exit of the second expansion valveto the suction side of the compressorvia the second heat exchangerinto a saturation temperature of the refrigerant during the cooling operation, or a saturation temperature of the refrigerant in the second heat exchangerfunctioning as an evaporator of the refrigerant. Thus, when the second heat exchangeris provided with a temperature sensor, the temperature of the refrigerant detected by the temperature sensor may be the evaporation temperature of the refrigerant.
Unknown
October 2, 2025
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