Patent Application
20240302066
The present disclosure relates to an air-conditioning apparatus and a refrigerant leakage detection system.
In the related art, there has been disclosed a refrigerant leakage detection system that detects leakage of refrigerant to improve the maintenance or safety of an air-conditioning apparatus. For example, Patent Literature 1 discloses a technique in which, if refrigerant leaks from a pipe of an indoor unit while operation is stopped, refrigerant leakage detection is performed in accordance with a difference between an ambient air temperature and a temperature of the pipe by using a reduction in temperature due to a reduction in the pressure in the pipe.
In an air conditioning indoor unit disclosed in Patent Literature 1, however, it is difficult to detect a so-called slow leak in which a small amount of refrigerant leaks slowly. This is because, in a slow leak, a reduction in pressure per unit time, that is, a reduction in temperature is very small and it is therefore difficult to detect a temperature difference between ambient air and a pipe. As a result, there is a possibility that a large amount of refrigerant leaks without the leakage being noticed.
The present disclosure has been made to overcome such an issue. The present disclosure aims to detect refrigerant leakage with certainty regardless of the form of refrigerant leakage by measuring the amount of refrigerant contained in an air-conditioning apparatus.
An air-conditioning apparatus according to an embodiment of the present disclosure includes: a container in which refrigerant in a liquid state can be present; a heating unit that heats the container; a temperature detection unit that detects a temperature of the container; a storage unit that stores a first time period of application of heat from when the heating unit starts applying heat until when a detection result provided by the temperature detection unit reaches a predetermined temperature, and a time when the first time period of application of heat was acquired; and a leakage determination unit that compares the first time period of application of heat stored in the storage unit with a reference time period stored in the storage unit in advance and determines whether or not there is refrigerant leakage.
In the air-conditioning apparatus according to the embodiment of the present disclosure, the container in which liquid refrigerant is present is heated by the heating unit, and a change in the temperature of the container is detected. Furthermore, a determination is made as to whether or not there is refrigerant leakage by comparing a plurality of temperature detection results acquired at different timings. Consequently, the amount of refrigerant contained in the air-conditioning apparatus can be estimated, and refrigerant leakage can be detected regardless of the form of leakage.
Embodiments for implementing the present disclosure will be described with reference to the accompanying drawings. In figures, the same or corresponding portions are denoted by the same reference signs, and a repeated description thereof is appropriately simplified or omitted. Note that the following embodiments are not intended to limit the scope of the present disclosure.
Furthermore, as an air-conditioning apparatus and a refrigerant leakage detection system according to the present disclosure, any air-conditioning apparatus and any refrigerant leakage detection system that include a configuration to be disclosed below can be used regardless of the type of a refrigerant circuit. Although, in the following description, an example will be described in which an air-conditioning apparatus according to the present disclosure is used in a relatively simple refrigerant circuit, there is no problem with the use of an air-conditioning apparatus according to the present disclosure, for example, in a more complicated refrigerant circuit including a plurality of indoor units.
In the outdoor unit 101, there are disposed a compressor 1, a flow switching device 2, an outdoor heat exchanger 3, an upstream-side expansion unit 4, a downstream-side expansion unit 5, an outdoor air-sending device 7, and a liquid storage container 20. Furthermore, a heating unit 21 and a temperature detection unit 22 are installed at the liquid storage container 20.
In the indoor unit 102, an indoor heat exchanger 6 and an indoor air-sending device 8 are disposed. The compressor 1, the flow switching device 2, the outdoor heat exchanger 3, the upstream-side expansion unit 4, the liquid storage container 20, and the downstream-side expansion unit 5 that are disposed in the outdoor unit 101, and the indoor heat exchanger 6 disposed in the indoor unit 102 are connected with a pipe, such as a copper pipe, to form a refrigerant circuit. Refrigerant, such as R32 (difluoromethane), circulates through the refrigerant circuit. Note that, in Embodiment 1, the type of refrigerant that flows through the refrigerant circuit is not limited.
The compressor 1 is a piston-type, rotary-type, or scroll-type compressor. The compressor 1 sucks and compresses low-pressure refrigerant and discharges high-temperature, high-pressure gaseous refrigerant. Note that the compressor 1 may be a compressor that is caused to operate at a fixed frequency or may be a compressor that is connected to an inverter circuit and is caused to operate at any frequency.
The flow switching device 2 is, for example, a four-way valve and has a function of switching between flow passages to switch between the flow passages in accordance with whether the air-conditioning apparatus 100 performs a cooling operation or a heating operation. When the air-conditioning apparatus 100 performs the cooling operation, the flow switching device 2 connects a discharge port of the compressor 1 with the outdoor heat exchanger 3 and simultaneously connects the indoor heat exchanger 6 with a suction port of the compressor 1. Furthermore, in the heating operation, the flow switching device 2 connects the discharge port of the compressor 1 with the indoor heat exchanger 6 and connects the outdoor heat exchanger 3 with the suction port of the compressor 1.
The outdoor heat exchanger 3 is a fin-and-tube heat exchanger constituted, for example, by a circular tube and a thin plate-like aluminum fin. In the outdoor heat exchanger 3, heat is exchanged between refrigerant flowing through the inside and outdoor air introduced into the outdoor unit 101 by the outdoor air-sending device 7 to be described. The outdoor heat exchanger 3 operates as a condenser when the air-conditioning apparatus 100 performs the cooling operation, and the outdoor heat exchanger 3 operates as an evaporator when the air-conditioning apparatus 100 performs the heating operation.
Furthermore, the outdoor air-sending device 7 is disposed near the outdoor heat exchanger 3. The outdoor air-sending device 7 is an air-sending device, such as a propeller fan. When the outdoor air-sending device 7 operates, outdoor air is introduced into the outdoor unit 101 from an opening provided in a casing of the outdoor unit 101. The outdoor air introduced into the outdoor unit 101 exchanges heat with refrigerant flowing through the outdoor heat exchanger 3. Air having been subjected to heat exchange flows outside the outdoor unit 101 from another opening provided in the outdoor unit 101.
The upstream-side expansion unit 4 is a device that reduces the pressure of refrigerant having flowed thereinto and is, for example, a solenoid expansion valve whose opening degree can be controlled. The upstream-side expansion unit 4 is disposed between the outdoor heat exchanger 3 and the liquid storage container 20. When the air-conditioning apparatus 100 performs the cooling operation, the upstream-side expansion unit 4 reduces the pressure of high-pressure liquid refrigerant flowing out of the outdoor heat exchanger 3 so that the refrigerant turns into medium-pressure liquid refrigerant or two-phase refrigerant. When the air-conditioning apparatus 100 performs the heating operation, the upstream-side expansion unit 4 reduces the pressure of medium-pressure liquid refrigerant or two-phase refrigerant flowing out of the liquid storage container 20 so that the refrigerant turns into low-pressure two-phase refrigerant. Furthermore, in a leakage detection operation to be described, the upstream-side expansion unit 4 is opened and does not reduce the pressure.
The liquid storage container 20 is a hollow container, and a pipe connected to the upstream-side expansion unit 4 and a pipe connected to the downstream-side expansion unit 5 are inserted into the inside of the container. This allows refrigerant to flow into and out of the inside of the liquid storage container 20. Note that, for the leakage detection operation to be described, it is desirable that the liquid storage container 20 have a capacity to store, in a liquid state, all of refrigerant contained in the air-conditioning apparatus 100.
Furthermore, the heating unit 21 and the temperature detection unit 22 are installed on an outer surface of the liquid storage container 20. The heating unit 21 is a unit, such as a heater, that heats an object. The heating unit 21 is in intimate contact with the outer surface of the liquid storage container 20 and heats the liquid storage container 20 when the leakage detection operation is performed. Note that it is desirable that the heating unit 21 be installed on a lower portion of a side or an underside of the liquid storage container 20 to heat liquid refrigerant present in the liquid storage container 20 with certainty. Furthermore, the temperature detection unit 22 measures a temperature of the liquid storage container 20 and is firmly fixed to the liquid storage container 20, for example, via soldering. As described later, the temperature detection unit 22 is used to determine whether liquid refrigerant in the liquid storage container 20 has evaporated completely, and it is therefore desirable that the temperature detection unit 22 be installed on the underside of the liquid storage container 20. Note that the temperature detection unit 22 has to be disposed so that the temperature detection unit 22 is not affected by the heating unit 21 because the temperature detection unit 22 measures a temperature of the liquid storage container 20. For example, it is desirable that the heating unit 21 and the temperature detection unit 22 be disposed at a certain distance from each other so that the temperature detection unit 22 is not affected by the heating unit 21.
As with the upstream-side expansion unit 5, the downstream-side expansion unit 5 is, for example, a solenoid expansion valve whose opening degree can be controlled. The downstream-side expansion unit 5 is disposed between the liquid storage container 20 and a first pipe 9. When the air-conditioning apparatus 100 performs the cooling operation, the downstream-side expansion unit 5 reduces the pressure of medium-pressure liquid refrigerant or two-phase refrigerant flowing out of the liquid storage container 20 so that the refrigerant turns into low-pressure two-phase refrigerant. When the air-conditioning apparatus 100 performs the heating operation, the downstream-side expansion unit 5 reduces the pressure of high-pressure liquid refrigerant flowing out of the indoor heat exchanger 6 so that the refrigerant turns into medium-pressure liquid refrigerant or two-phase refrigerant. Furthermore, in the leakage detection operation to be described, the downstream-side expansion unit 5 is in a closed state and shuts off the flow of refrigerant. Hence, it is desirable that the lower limit of the opening degree of the downstream-side expansion unit 5 be an extent to which the above-described function can be implemented.
Note that the sizes of the upstream-side expansion unit 4 and the downstream-side expansion unit 5, that is, the respective ranges of opening degrees that can be controlled are not limited to a particular range, and any ranges may be determined. Furthermore, the upstream-side expansion unit 4 and the downstream-side expansion unit 5 may have the same opening degree range or may have different opening degree ranges. Furthermore, “upstream-side” and “downstream-side” are terms for convenience in distinguishing between these expansion units in accordance with the flow of refrigerant when the air-conditioning apparatus 100 performs the cooling operation and are not intended to limit the configuration of the air-conditioning apparatus 100.
As with the outdoor heat exchanger 3, the indoor heat exchanger 6 is a fin-and-tube heat exchanger constituted, for example, by a circular tube and a thin plate-like aluminum fin. In the indoor heat exchanger 6, heat is exchanged between refrigerant flowing through the inside and indoor air introduced into the indoor unit 102 by the indoor air-sending device 8 to be described. The indoor heat exchanger 6 operates as an evaporator when the air-conditioning apparatus 100 performs the cooling operation, and the indoor heat exchanger 6 operates as a condenser when the air-conditioning apparatus 100 performs the heating operation.
Furthermore, the indoor air-sending device 8 is disposed near the indoor heat exchanger 6. The indoor air-sending device 8 is an air-sending device, such as a cross flow fan. When the indoor air-sending device 8 operates, indoor air is introduced into the indoor unit 102 from an opening provided in a casing of the indoor unit 102. The indoor air introduced into the indoor unit 102 exchanges heat with refrigerant flowing through the indoor heat exchanger 6. Air having been subjected to heat exchange flows into a room from another opening provided in the indoor unit 102.
In the air-conditioning apparatus 100 described above, during the cooling operation, refrigerant flows as indicated by a solid arrow in
On the other hand, during the heating operation, refrigerant flows as indicated by a dashed arrow in
Note that the liquid storage container 20 adjusts a difference between the amounts of refrigerant necessary for the above-described respective cooling and heating operations. In the air-conditioning apparatus 100, there are, mainly according to capacities of the outdoor heat exchanger 3, the indoor heat exchanger 6, the pipe 9, and the pipe 9a, a case where a larger amount of refrigerant is necessary for the cooling operation and a case where a larger amount of refrigerant is necessary for the heating operation. The liquid storage container 20 is a device for storing such a difference between the amounts of refrigerant.
The storage unit 51 stores, for example, an operation program necessary for an operation performed by the air-conditioning apparatus 100, an input signal from a user, and a detection result provided by the temperature detection unit 22. Specifically, results acquired by the acquisition unit 52, the input unit 54, and the leakage determination unit 55 are stored.
The acquisition unit 52 receives a signal from a sensor, such as the temperature detection unit 22, installed in the air-conditioning apparatus 100, or a signal from another detection unit, which is not illustrated, installed in the air-conditioning apparatus 100.
The operation unit 53 operates various elements of the air-conditioning apparatus 100, for example, by using an operation program stored in the storage unit 51, an input signal input by the user, and a value acquired by the acquisition unit 52. For example, the operation unit 53 controls an operating frequency of the compressor 1 to adjust the capacity of the air-conditioning apparatus 100 or operates the flow switching device 2 to switch between the cooling operation and the heating operation.
The input unit 54 is, for example, a wireless remote control separate from the air-conditioning apparatus 100 and is an unit via which the user of the air-conditioning apparatus 100 inputs desired operating conditions. Operating conditions input to the input unit 54 are stored in the storage unit 51.
The leakage determination unit 55 has a function of determining leakage of refrigerant from the air-conditioning apparatus 100. More specifically, a determination of refrigerant leakage is made in accordance with a detection result provided by the temperature detection unit 22 after the heating unit 21 at the liquid storage container 20 starts applying heat. A more detailed method of determining refrigerant leakage will be described later.
The notification unit 56 notifies the user of a determination result provided by the leakage determination unit 55. A specific form of the notification unit 56 is not limited to a particular form, and there are various possible forms. For example, the notification unit 56 may be a lamp provided in the indoor unit 102 and may light up when the leakage determination unit 55 determines that refrigerant leakage has occurred. Alternatively, the notification unit 56 may be an accompanying remote control with a monitor in the air-conditioning apparatus 100 and may notify the monitor of the occurrence of refrigerant leakage when refrigerant leakage has occurred. Furthermore, the notification unit 56 may send information via communication and may send information to a maintenance center for the air-conditioning apparatus 100 or a smartphone of the user when refrigerant leakage has occurred.
The controller 50 having the above-described functions can have any configuration. The controller 50 may be constituted, for example, by a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), and a communication circuit that are installed in the air-conditioning apparatus 100. Alternatively, the controller 50 may be constituted by a CPU, a ROM, a RAM, and a communication circuit that are installed in a centralized system other than the air-conditioning apparatus 100. Alternatively, the controller 50 may be of a compound type in which some functions are implemented, for example, by a CPU installed in the air-conditioning apparatus 100 and the other functions are implemented by a centralized system.
Next, a method by which the air-conditioning apparatus 100 performs an operation will be described. Note that an operation having a technical feature in the air-conditioning apparatus 100 is a refrigerant leakage determination operation. Thus, a description of the cooling operation and the heating operation is omitted, and only the refrigerant leakage determination operation will be described below.
In S101, the air-conditioning apparatus 100 performs a refrigerant collection operation. The refrigerant collection operation herein refers to an operation in which refrigerant is collected into the liquid storage container 20 in a liquid state. In the refrigerant collection operation, the flow switching device 2 is connected to a cooling operation state, the upstream-side expansion unit 4 is put into an open state (the opening degree is large), and the downstream-side expansion unit 5 is put into a closed state (the opening degree is small). Subsequently, the compressor 1 is caused to operate, and the outdoor air-sending device 7 is also caused to operate.
In such a situation, refrigerant present in the pipe 9, the indoor heat exchanger 6, and the pipe 9a is sucked into the compressor 1. Furthermore, refrigerant does not flow into the pipe 9, the indoor heat exchanger 6, and the pipe 9a anew since the downstream-side expansion unit 5 is in the closed state. The refrigerant sucked into the compressor 1 flows into the outdoor heat exchanger 3 via the flow switching device 2. In the outdoor heat exchanger 3, the refrigerant exchanges heat with air introduced into the outdoor unit 101 by the outdoor air-sending device 7 to turn into liquid refrigerant. The liquid refrigerant having flowed out of the outdoor heat exchanger 3 is not reduced in pressure since the upstream-side expansion unit 4 is in the open state and flows into the liquid storage container 20. The refrigerant having flowed into the liquid storage container 20 does not flow out of the liquid storage container 20 since the downstream-side expansion unit 5 is in the closed state and stays in a liquid state in the liquid storage container 20. When the air-conditioning apparatus 100 is caused to operate in this way, most of the refrigerant contained in the air-conditioning apparatus 100 is stored in the liquid storage container 20. After the refrigerant is stored in the liquid storage container 20, the compressor 1 is stopped.
In S102, the heating unit 21 is caused to operate. Note that a time period during which the heating unit 21 applies heat may be determined in advance or may be a time period that elapses before a temperature detected by the temperature detection unit 22 changes as described later. Furthermore, the downstream-side expansion unit 5 is maintained in the closed state while the heating unit 21 is applying heat.
In a situation between the point i and a point ii in
Here, a time period that elapses before the temperature detected by the temperature detection unit 22 reaches Teii depends on the amount of liquid refrigerant in the liquid storage container 20. This is because, in a case where the amount of liquid refrigerant in the liquid storage container 20 is small, the liquid refrigerant evaporates early (for example, evaporation is completed at a time Ta) and the temperature of the liquid storage container 20 rises but because, in a case where the amount of liquid refrigerant in the liquid storage container 20 is large, the liquid refrigerant takes time to evaporate (for example, evaporation is completed at a time Tb) and then the temperature of the liquid storage container 20 rises.
In S103, a time period (hereinafter referred to as a time period of application of heat) that elapses before the temperature detected by the temperature detection unit 22 in S102 reaches the predetermined temperature Tell is recorded. In an example of
In S104, a first time period of application of heat acquired in S103 is compared with a reference time period stored in the storage unit 51, for example, a time period of application of heat stored in the past (for example, a last time period of application of heat acquired in S103). In this case, the first time period of application of heat may be regarded as a first time period of application of heat, and a time period of application of heat stored in the past may be regarded as a second time period of application of heat. The leakage determination unit 55 determines whether the first time period of application of heat is shorter than the second time period of application of heat. When the first time period of application of heat is shorter than the second time period of application of heat, operation control proceeds to S106. On the other hand, when the first time period of application of heat is equivalent to the second time period of application of heat, the operation control proceeds to S105.
Note that, in S104, the fact that the second time period of application of heat is equivalent to the first time period of application of heat does not refer to the fact that two time periods described above are in exact agreement with each other. For example, if a difference between the second time period of application of heat and the first time period of application of heat is within a predetermined range (for example, within a range of 10%), the above-described two time periods of application of heat may be regarded as equivalent to each other. This is because it can be considered that, even when the refrigerant collection operation is performed in S101, the amount of refrigerant that stays in the liquid storage container 20 slightly varies each time.
In S105, the leakage determination unit 55 determines that no refrigerant leakage has occurred, and the operation control proceeds to S107. This is because it can be determined from the result in S104 that the amounts of refrigerant stored in the liquid storage container 20 this time and in the past are equivalent to each other and it is presumed that no refrigerant leakage has occurred. Note that, at this time, it is desirable that the storage unit 51 be caused to store a date and time when the determination was made. This is to make sure that, when refrigerant leakage occurs in the future, the date and time thereof can be estimated.
In S106, the leakage determination unit 55 determines that refrigerant leakage has occurred, and the operation control proceeds to S107. This is because it can be determined that the amount of refrigerant stored in the liquid storage container 20 this time is smaller than that in the past, that is, it is presumed that refrigerant leakage has occurred. Note that, at this time as well, it is desirable that the storage unit 51 be caused to store a date and time when the determination was made. This is to make sure that the fact that refrigerant leakage had occurred at a time when at least a latest determination in S104 was made can be confirmed.
In S107, the notification unit 56 is notified of whether refrigerant leakage has occurred. For example, if the notification unit 56 is a lamp provided in the indoor unit 102, the lamp is caused to light up when refrigerant leakage has occurred. Alternatively, if the notification unit 56 is a remote control with a monitor, the notification unit 56 notifies the monitor of the occurrence of refrigerant leakage when refrigerant leakage has occurred. Furthermore, if the notification unit 56 is a unit that sends information, the notification unit 56 sends information to a maintenance center or a smartphone of the user when refrigerant leakage has occurred.
The refrigerant leakage determination operation described above is performed at any timing. For example, the operation may be performed after each time the air-conditioning apparatus 100 is stopped by the user. Alternatively, the operation may be performed when the air-conditioning apparatus 100 has not been used for a predetermined period (for example, 10 days). Alternatively, the operation may be performed periodically, such as once per predetermined period (for example, 24 hours). Note that it is desirable that, if the refrigerant leakage determination operation is performed periodically, the operation be performed during night-time hours. This is because the air-conditioning apparatus 100 is likely to have been stopped during night-time hours and the influence of an outdoor air temperature to be described can be reduced.
Furthermore, in comparing time periods of application of heat in S104, there is no second time period of application of heat as an object for comparison in the first refrigerant leakage determination operation after construction of the air-conditioning apparatus 100. In this case, for example, experimental data stored in the storage unit 51 in advance may be regarded as a second time period of application of heat, and a comparison may be made.
The above-described air-conditioning apparatus 100 achieves the following effects. In the refrigerant leakage determination operation performed by the air-conditioning apparatus 100, after refrigerant is collected into the liquid storage container 20, the refrigerant in the liquid storage container 20 is caused to evaporate, and a determination of refrigerant leakage is made in accordance with an evaporation time period thereof. It can be considered that about the same amount of refrigerant stays in the liquid storage container 20 each time via collection of refrigerant as long as no refrigerant leakage has occurred, and thus refrigerant leakage can be detected even when the amount of refrigerant that has leaked is small.
Furthermore, while the air-conditioning apparatus 100 is stopped (when the air-conditioning apparatus 100 is not conditioning air), the air-conditioning apparatus 100 can make a refrigerant leakage determination. Thus, even when the air-conditioning apparatus 100 is not being used, such as in an intermediate season, a refrigerant leakage determination can be made. Consequently, the user can notice refrigerant leakage early, and safety can be secured quickly. Furthermore, if refrigerant leakage occurs in the intermediate season, a repair service can be requested avoiding the busiest season for a manufacture.
Note that the configuration of the air-conditioning apparatus 100 described above is an example of a configuration of an air-conditioning apparatus according to the present disclosure, and various modifications can be made thereto within the scope of the gist of the present disclosure. For example, a plurality of indoor units 102 may be included in the air-conditioning apparatus 100.
Furthermore, in comparing the first time period of application of heat with the second time period of application of heat in S104, a correction may be made using an outdoor air temperature.
For that reason, an outdoor air temperature is detected by the temperature detection unit 22 or another temperature detection unit disposed in the outdoor unit 101 before application of heat is started in S102, and the outdoor air temperature is stored in the storage unit 51. Subsequently, in comparing the first time period of application of heat with the second time period of application of heat in S104, a correction is made in consideration of a last outdoor air temperature and a latest outdoor air temperature. A specific correction value is determined as follows. When the latest outdoor air temperature is Teout1 and a past outdoor air temperature is Teout2, enthalpy differences ΔHnow and ΔHlast between saturated gas and saturated liquid at the respective outdoor air temperatures can be obtained from a physical property value of refrigerant. Here, when the first time period of application of heat is Tenow and the second time period of application of heat is Telast, the leakage determination unit 55 determines in S104 whether or not the following expression (1) is satisfied.
In the expression (1), ΔHnow/ΔHlast functions as a correction term. When the above-described expression holds true, that is, when Tenow is smaller than Telast that has been corrected, the leakage determination unit 55 determines that refrigerant leakage has occurred. On the other hand, when Tenow is equivalent to or more than Telast that has been corrected, the leakage determination unit 55 determines that no refrigerant leakage has occurred. Hence, the storage unit 51 is caused to store a physical property value of the refrigerant contained in the air-conditioning apparatus 100, and the above-described correction is made, thereby making it possible to reduce the influence of an outdoor air temperature in the refrigerant leakage determination operation. Note that, to reduce the influence of an outdoor air temperature in this way, it is desirable to perform a periodic refrigerant leakage determination operation during night-time hours. This is because it can be considered that a change in outdoor air temperature due to the influence of solar radiation is reduced during night-time hours.
Alternatively, in the refrigerant leakage determination operation illustrated in
In this case, in S103, the amount of rise in temperature per unit time is stored in the storage unit 51. Subsequently, in S104, the latest amount of rise in temperature per unit time (first amount of rise in temperature) is compared with the past amount of rise in temperature per unit time (second amount of rise in temperature). Here, the leakage determination unit 55 determines whether the first amount of rise in temperature is larger than the second amount of rise in temperature. When the first amount of rise in temperature is larger than the second amount of rise in temperature, the operation control proceeds to S106. On the other hand, when the first amount of rise in temperature is equivalent to the second amount of rise in temperature, the operation control proceeds to S105.
In S105, it is presumed, from the fact that the two amounts of rise in temperature are equivalent to each other, that an equivalent amount of refrigerant is present in the liquid storage container 20, and thus it is determined that no refrigerant leakage has occurred. On the other hand, in S106, it is presumed, from the fact that the first amount of rise in temperature is larger than the second amount of rise in temperature, that the amount of refrigerant in the liquid storage container 20 is smaller than the last amount of refrigerant, and thus it is determined that refrigerant leakage has occurred.
If such a refrigerant leakage determination operation is performed, all of the refrigerant in the liquid storage container 20 does not have to be caused to evaporate, thus reducing a time period taken to perform the refrigerant leakage determination operation.
Next, Embodiment 2 of the present disclosure will be described with reference to
Hence, in the air-conditioning apparatus 100a, the amount of refrigerant that stays in the liquid storage container 20 takes its own course according to operating conditions before the air-conditioning apparatus 100 is stopped, and an outdoor air temperature. Consequently, when the liquid storage container 20 is heated by the heating unit 21, a time period that elapses before a temperature detected by the temperature detection unit 22 rises varies each time.
However, it can be considered that, under similar latest operating conditions and similar conditions, such as an outdoor air temperature, almost an equivalent amount of refrigerant stays in the liquid storage container 20 when the air-conditioning apparatus 100a is stopped. Hence, in a period, such as the summer season or the winter season, during which it is almost certain that the air-conditioning apparatus 100a is caused to operate for cooling or heating and it can be considered that conditions, such as an outdoor air temperature, do not change significantly, it can be considered that an equivalent amount of refrigerant stays in the liquid storage container 20 after each operation of the air-conditioning apparatus 100a. Consequently, even if the refrigerant collection operation is not performed, a refrigerant leakage determination can be made by using the application of heat by the heating unit 21 and a detection result provided by the temperature detection unit 22.
Note that details of the refrigerant leakage determination operation may be changed to enhance the accuracy of a leakage determination.
In
Note that operating conditions of the preliminary operation in S201 do not have to be limited to one condition. For example, the summer season, the intermediate season, or the winter season may be determined in accordance with an outdoor air temperature, and the preliminary operation may be performed under operating conditions defined for each season. In that case, note that, in comparing time periods of application of heat in S104, the first time period of application of heat is compared with the second time period of application of heat obtained when the preliminary operation was performed under the same operating conditions.
The above-described air-conditioning apparatus 100a achieves the following effects. In the air-conditioning apparatus 100a, the liquid storage container 20 is disposed on a suction port side of the compressor 1. This can cause the liquid storage container 20 to function as an accumulator, and refrigerant just before being sucked into the compressor 1 can be separated into gas and liquid. Thus, only gaseous refrigerant is sucked into the compressor 1, enabling an increase in the reliability of the compressor 1.
An air-conditioning apparatus and a refrigerant leakage detection system according to the present disclosure can be widely used in a space that has to be air-conditioned regardless of their uses and structures.
1: compressor, 2: four-way valve, 3: outdoor heat exchanger, 4: first expansion valve, 5: second expansion valve, 6: indoor heat exchanger, 7: indoor air-sending device, 8: outdoor air-sending device, 9, 9a: pipe, 20: liquid storage device, 21: heating unit, 22: temperature detection unit, 50: controller, 51: storage unit, 52: acquisition unit, 53: operation unit, 54: input unit, 55: leakage determination unit, 56: notification unit, 60: communication unit, 100, 100a: air-conditioning apparatus, 101: outdoor unit, 102: indoor unit
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/004440 | 2/4/2022 | WO |
