JP6397758B2 - Refrigeration cycle equipment - Google Patents

Description

  Embodiments described herein relate generally to a refrigeration cycle apparatus having a function of detecting refrigerant leakage.

  A refrigeration cycle mounted on an air conditioner or the like includes a compressor, a condenser, a decompressor, and an evaporator. The refrigerant charged in advance is compressed by the compressor, and the refrigerant discharged from the compressor is condensed by the condenser and decompressor. Return to the compressor through the evaporator.

JP 2000-304388 A

  The compressor, condenser, decompressor, and evaporator of the refrigeration cycle are sequentially connected by piping. For this reason, a refrigerant | coolant may leak from the connection part of a piping, a joint line, etc. Since the leakage of the refrigerant causes a reduction in the capacity of the on-board equipment and damage to the component parts, it is desired that the refrigerant can be reliably detected.

  An object of an embodiment of the present invention is to provide a refrigeration cycle apparatus capable of reliably detecting refrigerant leakage.

The refrigeration cycle apparatus according to claim 1 includes a refrigeration cycle filled with a refrigerant, a temperature sensor attached to the refrigeration cycle, and a pressure sensor that detects a low-pressure side refrigerant pressure of the refrigeration cycle. detecting means for detecting a saturation evaporation temperature of the refrigerant by calculation based on the pressure, if the detected temperature of the temperature sensor is lower than the saturated evaporation temperature detected by said detecting means, the refrigerant in the refrigeration cycle is leaking and a determining means for determining a.

The block diagram which shows the structure of 1st and 2nd embodiment. The flowchart which shows the control of 1st Embodiment. The figure which shows the relationship between the saturated vapor curve of 1st Embodiment, and detected temperature. The flowchart which shows the control of 2nd Embodiment. The figure which shows the relationship between the saturated vapor curve of 2nd Embodiment, and detected temperature. The block diagram which shows the structure of 3rd Embodiment. The flowchart which shows the control of 3rd Embodiment.

[1] First embodiment
Hereinafter, application to a refrigeration cycle apparatus such as an air conditioner will be described as a first embodiment of the present invention.

  As shown in FIG. 1, an outdoor heat exchanger 3 is connected to a discharge port of a compressor 1 via a four-way valve 2, and a packed valve is connected to the outdoor heat exchanger 3 via an electric expansion valve 4 serving as a decompressor. 5 is connected by piping. An indoor heat exchanger 6 is connected to the packed valve 5 by piping, and a packed valve 7 is connected to the indoor heat exchanger 6 by piping. The intake port of the compressor 1 is connected to the packed valve 7 through the four-way valve 2 and the accumulator 8 by piping. A heat pump type refrigeration cycle is constituted by these pipe connections, and the refrigerant is filled in the refrigeration cycle.

  In the vicinity of the outdoor heat exchanger 3, an outdoor fan 9 that sucks outside air and passes it through the outdoor heat exchanger 3 is disposed. An indoor fan 10 that sucks indoor air and passes it through the indoor heat exchanger 6 is disposed in the vicinity of the indoor heat exchanger 6.

  The compressor 1 sucks refrigerant, compresses and discharges the sucked refrigerant, and is driven at a variable speed by electric power supplied from an inverter. The electric expansion valve 4 is a pulse motor valve (PMV) whose opening degree changes continuously according to the number of input drive pulses.

  During cooling, the refrigerant discharged from the compressor 1 flows to the outdoor heat exchanger 3 through the four-way valve 2 as indicated by arrows. The refrigerant flowing out of the outdoor heat exchanger 3 flows to the indoor heat exchanger 6 through the electric expansion valve 4 and the packed valve 5. The refrigerant flowing out of the indoor heat exchanger 6 is sucked into the compressor 1 through the packed valve 7, the four-way valve 2, and the accumulator 8. With this refrigerant flow, the outdoor heat exchanger 3 functions as a condenser, and the indoor heat exchanger 6 functions as an evaporator.

  During heating, the flow path of the four-way valve 2 is switched so that the refrigerant discharged from the compressor 1 flows through the four-way valve 2 and the packed valve 7 to the indoor heat exchanger 6. The refrigerant flowing out of the indoor heat exchanger 6 flows to the outdoor heat exchanger 3 through the packed valve 5 and the electric expansion valve 4. The refrigerant flowing out of the outdoor heat exchanger 3 is sucked into the compressor 1 through the four-way valve 2 and the accumulator 8. With this refrigerant flow, the indoor heat exchanger 6 functions as a condenser, and the outdoor heat exchanger 3 functions as an evaporator.

  The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the electric expansion valve 4, the accumulator 8, and the outdoor fan 9 are accommodated in the outdoor unit A, and the indoor heat exchanger 6 and the indoor fan 10 are accommodated in the indoor unit B. .

  In the outdoor unit A, a temperature sensor 21 for detecting the discharge refrigerant temperature Td is attached to the discharge side pipe (high pressure side pipe) between the compressor 1 and the four-way valve 2. A temperature sensor 22 for detecting the heat exchanger temperature Tc is attached to the outdoor heat exchanger 3 on the cooling refrigerant outflow side. A temperature sensor 23 for detecting the temperature Tw of the liquid refrigerant or the two-phase refrigerant (liquid and gas) is attached to the liquid side pipe between the outdoor heat exchanger 3 and the packed valve 5. A temperature sensor 27 for detecting the low-pressure side refrigerant temperature Tu is attached to the low-pressure side pipe between the four-way valve 2 and the accumulator 8. A temperature sensor 28 for detecting the suction refrigerant temperature Ts is attached to the suction side pipe between the accumulator 8 and the compressor 1. Further, a pressure sensor 31 for detecting the low-pressure side refrigerant pressure Pu is attached to the low-pressure side pipe between the four-way valve 2 and the accumulator 8.

  In the indoor unit B, a temperature sensor 24 for detecting the temperature Tw of the liquid refrigerant or the two-phase refrigerant is attached to the liquid side pipe between the packed valve 5 and the indoor heat exchanger 6. A temperature sensor 25 that detects the heat exchanger temperature Te is attached to the indoor heat exchanger 6 at a position on the cooling refrigerant inflow side. A temperature sensor 26 for detecting the temperature Tg of the gas refrigerant is attached to the gas side pipe between the indoor heat exchanger 6 and the packed valve 7.

  The detected temperatures of the temperature sensors 21 to 28 are collectively referred to as “Tx”.

  On the other hand, the control unit 40 includes a microcomputer and its peripheral circuits, and controls the outdoor unit A and the indoor unit B. A remote control type operation indicator (referred to as a remote controller) 41 and a reset switch 42 are connected to the control unit 40. The remote controller 41 is for setting operating conditions of the air conditioner. The reset switch 42 is an automatic return type push button switch and is disposed on a control circuit board or the like.

The control unit 40 has the following functions (1) and (2) as main functions related to refrigerant leakage detection.
(1) Detection means for detecting the saturation evaporation temperature Th of the refrigerant in the refrigeration cycle.

  (2) Determination means for determining leakage of the refrigerant in the refrigeration cycle by comparing each detected temperature Tx of the temperature sensors 21 to 28 attached to the refrigeration cycle with the saturated evaporation temperature Th detected by the detection means.

  Specifically, the detection unit (1) includes a pressure sensor 31 that detects the low-pressure side refrigerant pressure Pu, and calculates a saturated evaporation temperature Th from the detected pressure Pu of the pressure sensor 31.

  Specifically, the determination means of (2) above is that the refrigerant from the refrigeration cycle when the detected temperature Tx of any of the temperature sensors 21 to 28 is lower than the saturated evaporation temperature Th detected by the detection means (Tx <Th). When the detected temperature Tx of any of the temperature sensors 21 to 28 is equal to or higher than the saturated evaporation temperature Th detected by the detecting means (Th ≦ Tx), the refrigerant leaks from the refrigeration cycle. And a means for determining that it is not.

Next, the control executed by the control unit 40 will be described with reference to the flowchart of FIG.
The control unit 40 detects (calculates) the saturation evaporation temperature Th of the refrigerant in the refrigeration cycle based on the detected pressure (low pressure side refrigerant pressure) Pu of the pressure sensor 31 (step S1).

  FIG. 3 is a saturation vapor curve showing the relationship between the low-pressure side refrigerant pressure Pu and the saturation evaporation temperature Th, and the saturation evaporation temperature Th increases as the low-pressure side refrigerant pressure Pu increases. When the low-pressure side refrigerant pressure Pu is “Pu1”, the saturation evaporation temperature Th is “Th1”.

  The saturation evaporation temperature Th of the refrigerant is the boiling point of the refrigerant, and varies depending on the pressure and the type of the refrigerant. For example, under normal pressure (atmospheric pressure), the boiling point of R410A refrigerant is −50.6 ° C., the boiling point of R22 refrigerant is −41 ° C., and the boiling point of R32 refrigerant is −51.7 ° C.

  The control unit 40 compares the detected temperatures Tx of the temperature sensors 21 to 28 attached to the piping and heat exchanger of the refrigeration cycle with the detected saturated evaporation temperature Th (step S2).

  When the refrigeration cycle is operating without refrigerant leakage, the high-pressure side refrigerant pressure of the refrigeration cycle is, for example, 2 to 4 MPaa, and the low-pressure side refrigerant pressure of the refrigeration cycle is, for example, 0.7 to 1.5 MPaa. Accordingly, the detected temperatures Tx of the temperature sensors 21 to 28 become a value “Tx2” that is equal to or higher than the saturation evaporation temperature Th1, as shown in FIG.

  When the refrigeration cycle is stopped in a state where there is no refrigerant leakage, the high-pressure side refrigerant pressure and the low-pressure side refrigerant pressure of the refrigeration cycle are values corresponding to the ambient temperature. For example, when an R32 refrigerant is used, the high-pressure side refrigerant pressure and the low-pressure side refrigerant pressure are 1.9 MPaa when the ambient temperature is 30 ° C., and 0.8 MPaa when the ambient temperature is 0 ° C.

  On the other hand, when the refrigerant rapidly leaks from somewhere in the refrigeration cycle, the pressure of the liquid refrigerant in the refrigeration cycle rapidly decreases to atmospheric pressure. Along with this, the temperature of the liquid refrigerant in the refrigeration cycle decreases to a value corresponding to the atmospheric pressure.

  For example, when the leak point of the refrigerant is a liquid phase region or a two-phase region, the refrigerant existing in the liquid phase region or the two-phase region suddenly drops in pressure and decreases in temperature. When the leaking portion of the refrigerant is in the gas region, the temperature decrease width of the refrigerant existing in the gas region is small. However, even if the leakage point of the refrigerant is in the gas region, the refrigerant existing in the liquid phase region or the two-phase region suddenly decreases in pressure and decreases in temperature.

  Therefore, the detected temperature Tx of at least one of the temperature sensors 21 to 28 is a value “Tx1” lower than the saturation evaporation temperature Th1 as shown in FIG.

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is a value “Tx2” that is equal to or higher than the saturation evaporation temperature Th1 (NO in Step S2), the control unit 40 determines that there is no refrigerant leakage (Step S2). S3). Based on this determination, the control unit 40 repeats the process from the first step S1.

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is a value “Tx1” that is lower than the saturation evaporation temperature Th1 (YES in Step S2), the control unit 40 determines that the refrigerant leak is “present” (Step S2). S4). Based on this determination, the control unit 40 stops the operation of the refrigeration cycle (operation of the compressor 1, the outdoor fan 9, and the indoor fan 10) and indicates that the refrigerant is leaking, for example, a character display or an icon on the remote controller 41. Notification is made by image display (step S5).

  By stopping the operation, it is possible to prevent problems such as a reduction in the capacity and damage of the refrigeration cycle equipment due to the operation being continued with the refrigerant leaking. In addition, the notification allows the user to recognize that the refrigerant is leaking. The recognized user can request maintenance / inspection.

  The control part 70 monitors operation of the reset switch 42 with a driving | operation stop and alerting | reporting (step S6). When the reset switch 42 is not turned on (NO in step S6), the control unit 40 continues the operation stop and notification (step S5).

  The worker who has received the request for maintenance / inspection turns on the reset switch 42 after repairing and eliminating the leakage of the refrigerant.

  When the reset switch 42 is turned on (YES in step S6), the control unit 40 cancels the operation stop and the notification (step S7). Based on this cancellation, the control unit 40 repeats the process from the first step S1.

  As described above, by detecting the saturated evaporation temperature Th of the refrigerant in the refrigeration cycle and determining the leakage of the refrigerant by comparing the detected saturated evaporation temperature Th with the detected temperatures Tx of the temperature sensors 21 to 28, the refrigeration cycle. It is possible to reliably detect the leakage of the refrigerant.

  In particular, since the saturation evaporation temperature Th of the refrigerant in the refrigeration cycle is detected and the saturation evaporation temperature Th is used as a reference value for comparison with respect to the temperature change of the refrigerant, the presence or absence of refrigerant leakage can be accurately determined regardless of the type of refrigerant. Can be caught.

  If a flammable refrigerant such as R32 refrigerant leaks, there is a risk of ignition, but if a refrigerant leak is detected, a notification to that effect will be made. Treatment can be taken.

[2] Second embodiment
The control unit 40 of the second embodiment has the following functions (11) and (12) instead of the functions (1) and (2) of the first embodiment.
(11) Detection means for detecting the saturation evaporation temperature Th of the refrigerant in the refrigeration cycle by calculation based on the detected pressure (low-pressure side refrigerant pressure) Pu of the pressure sensor 31.

  (12) A change amount ΔPu per unit time of the detected pressure Pu of the pressure sensor 31 is detected. If the change amount ΔPu is less than a predetermined value, the detected saturation evaporation temperature Th is set as the reference value Ths as it is, and the change amount When ΔPu is greater than or equal to a predetermined value, a temperature different from the detected saturated evaporation temperature Th by a predetermined value ΔTh is determined as a reference value Ths for a certain time ts, and any one of the temperature sensors 21 to 28 is less than the reference value Ths ( When Tx <Ths), it is determined that the refrigerant is leaking from the refrigeration cycle. When the detected temperature Tx of any of the temperature sensors 21 to 28 is equal to or higher than the reference value Ths (Ths ≦ Tx), the refrigerant is discharged from the refrigeration cycle. Determination means for determining that there is no leakage.

The predetermined value ΔTh and the predetermined time ts may be appropriately selected in consideration of the type of refrigerant, the capacity and thickness of the pipe through which the refrigerant passes, the capacity of the compressor 1, the responsiveness of detection by the temperature sensors 21 to 28, and the like. .
Other configurations are the same as those of the first embodiment. Therefore, the detailed description is abbreviate | omitted.

The control executed by the control unit 40 will be described with reference to the flowchart of FIG.
The control unit 40 detects (calculates) the saturated evaporation temperature Th of the refrigerant in the refrigeration cycle based on the detected pressure Pu of the pressure sensor 31, and the amount of change per unit time of the detected pressure Pu of the pressure sensor 31 at the time of detection. ΔPu is detected (step S11).

  As indicated by an arrow on the saturated vapor curve in FIG. 5, when the low-pressure pressure Pu of the refrigeration cycle changes in the increasing direction from “Pu1” to “Pu2”, the saturation evaporation temperature Th also increases from “Th1” to “Th2”. It changes in the upward direction.

  However, the temperature sensors 21 to 28 attached to the piping and heat exchanger of the refrigeration cycle are slower in detection response than the pressure sensor 31. That is, when the low-pressure side pressure Pu changes abruptly, the detection of the pressure sensor 31 follows the pressure change with good response, but the detection of the temperature sensors 21 to 28 causes a response delay with respect to the temperature change accompanying the pressure change. . For this reason, the detected temperature Tx of the temperature sensors 21 to 28 becomes a value Tx ′ lower than the actual value as shown in FIG. In this case, the refrigerant is erroneously determined to be “present” even though the refrigerant has not leaked.

  Therefore, the control unit 40 determines whether or not the change amount ΔPu detected in step S11 is a predetermined value or more (step S12).

  When the change amount ΔPu is less than the predetermined value (NO in step S12), the control unit 40 determines the saturation evaporation temperature Th2 detected in step S11 as the reference value Ths as it is (step S13), and detects each of the temperature sensors 21 to 28. The temperature Tx is compared with the reference value Ths (= Th2) (step S14).

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is equal to or higher than the reference value Ths (= Th2) (NO in step S14), the control unit 40 determines that there is no refrigerant leakage (step S15). Based on this determination, the control unit 40 repeats the process from the first step S11.

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is lower than the reference value Ths (= Th2) (YES in step S14), the control unit 40 determines that “there is refrigerant leakage” (step S16). The subsequent processes in steps S17, S18, and S19 are the same as the processes in steps S5, S6, and S7 in the first embodiment, and thus description thereof is omitted.

  On the other hand, when the change amount ΔPu is larger than the predetermined value in the determination in step S12 (YES in step S12), the control unit 40 starts the time count t from “0” (step S20). The predetermined time ts is compared (step S21).

  When the time count t is less than the predetermined time ts (NO in step S21), the control unit 40 sets a value Th2 ′ that is different from the saturation evaporation temperature Th2 detected in step S11 by a predetermined value ΔTh as a reference value Ths (step S22). The detected temperature Tx of each of the temperature sensors 21 to 28 is compared with the reference value Ths (step S23).

  When setting the reference value Ths, if the change amount ΔPu is a change in the increasing direction, the control unit 40 sets a value “Th2−ΔTh” lower than the saturation evaporation temperature Th2 detected in step S11 by a predetermined value ΔTh as the reference value Ths. If the change amount ΔPu is a change in the decreasing direction, a value “Th2 + ΔTh” that is higher than the saturation evaporation temperature Th2 detected in step S11 by a predetermined value ΔTh is determined as the reference value Ths.

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is equal to or higher than the reference value Ths (NO in step S23), the control unit 40 determines that there is no refrigerant leakage (step S24). Based on this determination, the control unit 40 returns to the time determination in step S21.

  If the detected temperature Tx of any of the temperature sensors 21 to 28 is less than the reference value Ths (= Th2 ′) (YES in step S23), the control unit 40 determines that “there is refrigerant leakage” (step S16). ). The description of subsequent steps S17 to S19 is omitted.

  When the time count t reaches a certain time ts (YES in step S21), the control unit 40 uses the saturation evaporation temperature Th2 detected in step S11 as it is as the reference value Ths as in the case where the change amount ΔPu is less than the predetermined value. Determine (step S13). The description of subsequent steps S14 to S19 is omitted.

As described above, the saturation evaporation temperature Th of the refrigerant is detected, and the change amount ΔPu per unit time of the detected pressure Pu of the pressure sensor 31 is detected. If the change amount ΔPu is equal to or greater than a predetermined value, the detected saturation is detected. A temperature different from the evaporation temperature Th by a predetermined value ΔTh is set as a reference value Ths, and the presence or absence of refrigerant leakage is determined by comparing the detected temperature Tx of the temperature sensors 21 to 28 with the reference value Ths, respectively. The refrigerant leakage can be accurately detected without error without being affected by the response delay of the detection.
Other operations and effects are the same as those of the first embodiment. Therefore, the description is omitted.

[3] Third embodiment
In the third embodiment, as shown in FIG. 6, a thermography camera (measuring means) 51 is disposed in the outdoor unit A as a measuring means for measuring the temperature distribution in the refrigeration cycle and its surroundings, and a thermographic camera ( Measuring means) 52 is arranged.

  The thermography camera 51 is arranged so that the compressor 1 and the accumulator 8 in which a large amount of liquid refrigerant exists and the periphery thereof become the measurement object, and captures the infrared energy emitted from the measurement object, thereby detecting the temperature of the measurement object. The distribution is measured as an image. The thermographic camera 52 is disposed so that the indoor heat exchanger 6 in which liquid refrigerant easily collects and its periphery become a measurement object, and captures infrared energy emitted from the measurement object, thereby detecting the temperature of the measurement object. The distribution is measured as an image.

The control unit 40 has the following function (3) in addition to the functions (1) and (2) of the first embodiment.
(3) A determination unit that determines the leakage of the refrigerant in the refrigeration cycle according to the measurement results of the thermographic cameras 51 and 52.

  As described in the first embodiment, when the leakage point of the refrigerant is the liquid phase region or the two-phase region, the refrigerant existing in the liquid phase region or the two-phase region suddenly decreases in pressure and temperature. When the leak point of the refrigerant is in the gas region, the temperature decrease width of the refrigerant existing in the gas region is small, but the refrigerant existing in the liquid phase region or the two-phase region rapidly decreases in pressure and decreases in temperature.

  As described in the first embodiment, when the refrigerant rapidly leaks from somewhere in the refrigeration cycle, the pressure of the liquid refrigerant in the refrigeration cycle rapidly decreases to atmospheric pressure. Along with this, the temperature of the liquid refrigerant in the refrigeration cycle decreases to a value corresponding to the atmospheric pressure.

  For example, when the leak point of the refrigerant is a liquid phase region or a two-phase region, the refrigerant existing in the liquid phase region or the two-phase region suddenly drops in pressure and decreases in temperature. When the leaking portion of the refrigerant is in the gas region, the temperature decrease width of the refrigerant existing in the gas region is small. However, even if the leakage point of the refrigerant is in the gas region, the refrigerant existing in the liquid phase region or the two-phase region suddenly decreases in pressure and decreases in temperature.

  Such a temperature drop causes a temperature drop in the compressor 1, the accumulator 8, the indoor heat exchanger 6, piping, and the like, and the temperature drop appears in a temperature distribution image that is a measurement result of the thermography cameras 51 and 52.

The control executed by the control unit 40 will be described with reference to the flowchart of FIG.
The control unit 40 detects the saturation evaporation temperature Th of the refrigerant in the refrigeration cycle based on the detected pressure (low pressure side refrigerant pressure) Pu of the pressure sensor 31 (step S1). Further, the control unit 40 analyzes whether or not the temperature distribution image obtained by the measurement of the thermographic cameras 51 and 52 includes a sudden temperature drop portion (step S1a).

  Then, the control unit 40 compares the detected temperatures Tx of the temperature sensors 21 to 28 with the detected saturated evaporation temperature Th (step S2).

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is a value “Tx2” that is equal to or higher than the saturation evaporation temperature Th1 (NO in step S2), the control unit 40 confirms the analysis result of step S1a (step S2a). .

  When the analysis result in step S1a is “not included” (NO in step S2a), the control unit 40 determines that there is no refrigerant leakage (step S3). Based on this determination, the control unit 40 repeats the process from the first step S1.

  When the detected temperature Tx of any of the temperature sensors 21 to 28 is a value “Tx1” lower than the saturation evaporation temperature Th1 (YES in step S2), or the analysis result of step S1a is “included” (step) The control unit 40 determines that “there is a refrigerant leak” (YES in S2a) (step S4). Subsequent steps S5, S6, and S7 are the same as those in the first embodiment, and a description thereof will be omitted.

  As described above, in addition to the process of determining the leakage of the refrigerant by comparing the detected temperature Tx and the saturated vapor temperature Th of each of the temperature sensors 21 to 28, the refrigerant is also obtained from the temperature distribution images obtained by the measurements of the thermographic cameras 51 and 52. By determining the leakage of the refrigerant, the leakage of the refrigerant in the refrigeration cycle can be detected with higher reliability.

If an attempt is made to measure the temperature distribution of the entire refrigeration cycle, a large number of thermographic cameras must be prepared, resulting in an increase in cost. On the other hand, in this embodiment, since the temperature distribution in the liquid refrigerant region where the temperature drop appears most prominently when the refrigerant leaks is mainly measured, only two thermographic cameras 51 and 52 need be prepared. Therefore, an increase in cost can be suppressed as much as possible.
Since other operations and effects are the same as those in the first embodiment, the description thereof is omitted.

[4] Modification
In each of the embodiments described above, an air conditioner has been described as an example of a refrigeration cycle apparatus. However, any apparatus equipped with a refrigeration cycle can be similarly applied to other apparatuses as well.

  In each of the above embodiments, the character display or icon image display of the remote control 41 is used as the notification means. However, in the case of a multi-type air conditioner that centrally manages a plurality of indoor units B, the concentration is arranged in the central control room. The character display or icon image display of the management controller may be used as the notification means. Not only character display and icon image display but also notification by voice synthesis, light emission, and light emission color change can be performed. In addition, an alarm device that issues an alarm in cooperation with other electric devices, a portable terminal such as a mobile phone device or a smartphone possessed by the user, or the like can be used as the notification means.

  In addition, each said embodiment and modification are shown as an example, and are not intending limiting the range of invention. The novel embodiments and modifications can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the spirit of the invention. In these embodiments and modifications, the scope of the invention is included in the gist, and is included in the invention described in the claims and the equivalents thereof.

  A ... outdoor unit, B ... indoor unit, 1 ... compressor, 2 ... four-way valve, 3 ... outdoor heat exchanger, 4 ... electric expansion valve (decompressor), 6 ... indoor heat exchanger, 8 ... accumulator, 21- 28 ... Temperature sensor, 31 ... Pressure sensor, 40 ... Control unit, 41 ... Remote control, 42 ... Reset switch

Claims (3)

A refrigeration cycle filled with refrigerant;
A temperature sensor attached to the refrigeration cycle;
A detection unit that includes a pressure sensor that detects a low-pressure side refrigerant pressure of the refrigeration cycle, and that detects a saturation evaporation temperature of the refrigerant by calculation based on a detection pressure of the pressure sensor ;
If the sensed temperature of the temperature sensor is lower than the detected saturated evaporation temperature, a determination unit and the refrigerant is leaking,
A refrigeration cycle apparatus comprising: When the change amount per unit time of the pressure detected by the pressure sensor is less than a predetermined value, the determination means determines the detected saturated evaporation temperature as a reference value, and the amount of change per unit time of the pressure detected by the pressure sensor Is equal to or higher than a predetermined value, a temperature different from the detected saturated evaporation temperature by a predetermined value is defined as a reference value for a certain period of time, and it is determined that the refrigerant is leaking when the temperature detected by the temperature sensor is less than the reference value To
The refrigeration cycle apparatus according to claim 1 . Measuring means for measuring the temperature distribution of the refrigeration cycle and its surroundings;
Determination means for determining leakage of the refrigerant according to a measurement result of the measurement means;
The refrigeration cycle apparatus according to claim 1 or 2, further comprising:

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