JP6008416B2 - Refrigeration apparatus and refrigerant leakage detection method for refrigeration apparatus - Google Patents

Description

  The present invention relates to a refrigeration apparatus and a refrigerant leak detection method for the refrigeration apparatus.

  In various stores such as supermarkets and convenience stores, refrigeration equipment such as showcases and refrigerators are used to display products such as refrigerated foods, frozen foods, and fresh foods. This refrigeration apparatus usually includes a compressor, a condenser, an evaporator, and the like, and cools various products by heat exchange using a refrigerant. If this refrigerant leaks from the refrigerant circuit of the refrigeration system, the cooling capacity will be reduced due to the lack of refrigerant, and it will not be possible to cool the product to the target temperature.

  Therefore, various techniques for detecting refrigerant (gas) leakage from the refrigeration apparatus have been proposed. For example, a technique for detecting a refrigerant leak by detecting a flow rate of a refrigerant flowing out from a liquid receiver of a refrigeration apparatus or a liquid level of the liquid receiver has been proposed (for example, see Patent Document 1 or Patent Document 2). In air conditioners (air conditioners), techniques have been proposed in which the temperature of each part of the device is detected to detect refrigerant leakage, or signs of refrigerant leakage are detected from temperature changes within a predetermined time (for example, , Patent Document 3, Patent Document 4 or Patent Document 5). Also, in a showcase in which a plurality of units are installed, a technique for observing the degree of superheat (evaporator inlet / outlet temperature difference) of the evaporator at the end of the pipe and observing the inside temperature of the showcase is disclosed. (For example, see Patent Document 6 or Patent Document 7).

JP-A-7-151432 JP-A-11-94408 JP-A-6-137725 JP 2005-257219 A JP 2008-267621 A JP 2008-249226 A JP 2009-92268 A

  However, the above-described technology requires an expensive sensor, a complicated system, and more complicated measurement software, which complicates the apparatus for detecting a refrigerant leak and increases the cost. In addition, as described above, in the technology for observing the degree of superheat of the evaporator and the temperature inside the showcase, if a considerable amount of refrigerant does not leak, the refrigerant leaks from the degree of superheat of the end evaporator and the temperature inside the showcase. It is difficult to detect, and a considerable amount of refrigerant will be released to the atmosphere for refrigerant leakage detection.

  As the above-mentioned refrigerant, a fluorocarbon refrigerant having a zero ozone depletion coefficient represented by an HFC (hydrofluorocarbon) refrigerant is used. The HFC refrigerant is a refrigerant having a high global warming potential, and is warming due to refrigerant leakage. There are concerns about the impact on Therefore, it is desired to detect the refrigerant leakage at an early stage. In particular, in recent surveys, when connecting multiple showcases at the site and performing refrigerant piping, for example, when using a separately installed showcase of on-site construction type, depending on the skill of the installer and maintenance after delivery. It has been found that a slow leak of refrigerant (gas) due to long-term use is conspicuous, and it is strongly desired to detect the refrigerant leak at an early stage.

  The present invention has been made in view of the above, and an object thereof is to provide a refrigeration apparatus and a refrigerant leakage detection method for a refrigeration apparatus that can detect refrigerant leakage at an early stage with a simple configuration at low cost. is there.

A first feature according to the present invention is a refrigeration apparatus comprising a compressor, a condenser, a liquid receiver, a decompression unit, and an evaporator, wherein the compressor, the condenser, the liquid receiver, the decompression unit, and A refrigerant pipe that connects the evaporators in order to circulate the refrigerant, and is provided in the middle of the refrigerant pipe between the receiver and the evaporator to open and close to adjust the refrigerant flow from the receiver to the evaporator A valve, a pressure detection unit that detects the pressure of the decompressed refrigerant flowing through the refrigerant pipe after being decompressed by the decompression unit, and a control unit that stops the compressor according to the pressure detected by the pressure detection unit Control the on-off valve to stop the refrigerant outflow from the receiver, determine the pump down time from the stop of the refrigerant outflow until the compressor stops, and from the refrigerant piping according to the determined pump down time It is to determine the presence or absence of refrigerant leakage.

  According to a second feature of the present invention, in the refrigeration apparatus according to the first feature described above, two on-off valves are provided, and one of the two on-off valves is provided on the outlet side of the receiver. The open / close valve on the receiver side, the other of the two open / close valves is the open / close valve on the evaporator side provided on the inlet side of the evaporator, and the control unit immediately before closing the open / close valve on the receiver side The opening / closing valve on the evaporator side is opened.

  According to a third feature of the present invention, in the refrigeration apparatus according to the first or second feature described above, the control unit stores a set value of the pump down time for each season, and stores each stored season. The set value is selected from the set values according to the current season, and the selected set value is compared with the obtained pump down time to determine the presence or absence of refrigerant leakage.

  According to a fourth feature of the present invention, in the refrigeration apparatus according to the third feature described above, the control unit controls the on-off valve to prevent the refrigerant from flowing out from the receiver in a state where no refrigerant leaks. The pump down time is obtained by stopping, and the stored set value for each season is corrected based on the obtained pump down time.

  According to a fifth feature of the present invention, in the refrigeration apparatus according to any one of the first to fourth features described above, the control unit can stabilize the ambient environment of the load-side evaporator once a day. In the predetermined time, it is determined whether or not there is a refrigerant leak using the pump-down time.

A sixth feature of the present invention is a refrigerant leakage detection method for a refrigeration apparatus, wherein the refrigerant is depressurized by a depressurization unit through a refrigerant pipe that sequentially connects a compressor, a condenser, a liquid receiver, a depressurization unit, and an evaporator. In the refrigeration system that detects the pressure of the refrigerant in the reduced pressure state and stops the compressor in accordance with the detected pressure, the pump from stopping the refrigerant outflow from the liquid receiver until the compressor stops The down time is obtained, and the presence or absence of refrigerant leakage from the refrigerant pipe is determined according to the obtained pump down time.

  According to a seventh feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to the sixth feature described above, two on-off valves are provided in the middle of the refrigerant pipe between the receiver and the evaporator. One of the two on-off valves is a receiver-side on-off valve provided on the outlet side of the receiver, and the other of the two on-off valves is on the evaporator side provided on the inlet side of the evaporator In this case, the opening / closing valve on the evaporator side is opened immediately before closing the opening / closing valve on the receiver side.

  According to an eighth aspect of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to the sixth or seventh aspect described above, a setting value of the pump down time for each season is stored, and the stored seasonal value is stored. The setting value is selected from the setting value according to the current season, and the selected setting value is compared with the obtained pump down time to determine the presence or absence of refrigerant leakage.

  According to a ninth feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to the eighth feature described above, in a state where no refrigerant leaks, the refrigerant outflow from the receiver is stopped and the pump down time is set. And the stored set value for each season is corrected based on the obtained pump down time.

  According to a tenth feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to any one of the sixth to ninth features described above, the ambient environment of the load-side evaporator is stabilized once a day. It is determined whether or not there is a refrigerant leak using the pump down time at a predetermined time.

  According to the first or sixth aspect of the present invention, the refrigerant outflow from the receiver is stopped, and the pump down time from the stop of the refrigerant outflow until the compressor stops is obtained, and the obtained The presence or absence of refrigerant leakage is determined according to the pump down time. As a result, it is possible to detect a refrigerant leak using the pump down time without requiring an expensive sensor, a complicated system, complicated measurement software, and the like, and further, it is possible to grasp a sign of the refrigerant leak. . As a result, it is possible to detect refrigerant leakage at an early stage with a simple configuration at low cost.

  According to the second or seventh feature of the present invention, the on-off valve on the evaporator side is opened just before the on-off valve on the receiver side is closed. As a result, even when the evaporator-side on-off valve is closed, detection of refrigerant leakage is started after the refrigerant is supplied to the evaporator, so it is possible to accurately determine the pump down time, The refrigerant leakage can be reliably detected using the pump down time.

  According to the third or eighth feature of the present invention, the setting value of the pump down time for each season is stored, and the setting value is selected according to the current season from the stored setting values for each season. The selected set value is compared with the determined pump down time to determine whether or not there is a refrigerant leak. Thereby, since the set value of the pump down time is selected and used according to the season, it is possible to reliably detect the refrigerant leakage even when using the pump down time that changes depending on the season.

  According to the fourth or ninth feature of the present invention, the pump from the stop of the refrigerant supply to the stop of the compressor after the refrigerant is stopped from flowing out in a state where no refrigerant leak has occurred. The down time is obtained, and the stored set value for each season is corrected based on the obtained pump down time. As a result, the set value of the pump down time for each season is corrected according to the ambient environment (for example, ambient temperature, pipe length, etc.) at the actual installation site during trial operation, etc. It is possible to detect the refrigerant leak using the setting corresponding to the above, and to detect the refrigerant leak more reliably.

  According to the fifth or tenth feature of the present invention, the judgment of the presence or absence of refrigerant leakage using the pump down time is performed once a day at a predetermined time when the ambient environment of the load-side evaporator is stable. Done. This makes it possible to prevent changes in the ambient environment on the load side (for example, ambient temperature) from affecting the measurement of the pump down time, so that the pump down time can be obtained accurately, and as a result The refrigerant leakage can be detected more reliably.

It is a figure which shows schematic structure of the freezing apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the refrigerant | coolant leak detection process which the refrigeration apparatus shown in FIG. 1 performs.

  An embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a refrigeration apparatus 1 according to an embodiment of the present invention includes a compressor 2 that compresses a refrigerant, a condenser 3 that condenses the compressed refrigerant, and a receiver that stores the condensed refrigerant. 4, a plurality of decompression units 5 that decompress the refrigerant, a plurality of evaporators 6 that evaporate the decompressed refrigerant, a refrigerant pipe 7 that circulates the refrigerant by connecting these units, and a control unit that performs various controls 8 and.

  The refrigerant pipe 7 is a flow path for circulating the refrigerant by sequentially connecting the compressor 2, the condenser 3, the liquid receiver 4, each decompression unit 5, and each evaporator 6, and is constituted by a pipe such as a copper pipe, for example. Has been. With respect to the flow path of the refrigerant pipe 7, each decompression unit 5 and each evaporator 6 are a set of one decompression unit 5 and one evaporator 6 arranged in series, and each set is connected in parallel. Yes. For example, an expansion valve is used as the decompression unit 5.

  The refrigerant flowing through the refrigerant pipe 7 circulates through the refrigerant pipe 7 while repeating the four steps of compression, condensation, expansion and evaporation. More specifically, the high-temperature and high-pressure gas refrigerant compressed by the compressor 2 flows into the condenser 3, is cooled by the condenser 3, liquefies by releasing condensation heat, and is stored in the liquid receiver 4. This liquid receiver 4 absorbs the fluctuation | variation of the refrigerant | coolant amount in each evaporator 6 by load fluctuation | variation.

  Thereafter, the normal-temperature and high-pressure liquid refrigerant stored in the liquid receiver 4 flows into each decompression unit 5 and is decompressed by each decompression unit 5 to have a reduced boiling point. The low-temperature and low-pressure liquid refrigerant in this state is boiled and evaporated by each evaporator 6, and cools by taking away the surrounding heat. The evaporated low-pressure gas refrigerant flows into the compressor 2, is compressed by the compressor 2, becomes a high-temperature high-pressure gas refrigerant that can be liquefied by air at normal temperature, and flows into the condenser 3 again.

  The refrigerant pipe 7 through which the refrigerant circulates is provided with a plurality of on-off valves 9a, 9b, 9c, and the low-pressure side pressure (low-pressure side refrigerant pressure) of the refrigerant flowing through the refrigerant pipe 7 is measured. A pressure detection unit 10 is provided.

  Each on-off valve 9 a, 9 b, 9 c is provided in the middle of the refrigerant pipe 7 and between the liquid receiver 4 and each decompression unit 5. In particular, the on-off valve 9 a is provided on the outflow side of the liquid receiver 4 and in the vicinity of the outflow port, and the flow of refrigerant from the liquid receiver 4 to each evaporator 6, that is, from the liquid receiver 4. Adjust the refrigerant outflow. Each on-off valve 9b, 9c is provided on the inlet side of the decompression section 5 and in the vicinity of the inlet, and adjusts the refrigerant inflow to each decompression section 5. As these on-off valves 9a, 9b, 9c, for example, electromagnetic valves are used. Each on-off valve 9 a, 9 b, 9 c is electrically connected to the control unit 8, and its driving is controlled by the control unit 8.

  The pressure detection unit 10 is provided in the middle of the refrigerant pipe 7 and between each evaporator 6 and the compressor 2. In particular, the pressure detection unit 10 is provided on the inlet side of the compressor 2 and in the vicinity of the inlet, and is electrically connected to the control unit 8. The pressure detection unit 10 measures the pressure of the decompressed refrigerant (gas) reduced by each decompression unit 5, that is, the low-pressure side refrigerant pressure, and outputs the measured refrigerant pressure to the control unit 8. As the pressure detection unit 10, various types of pressure sensors can be used.

  Further, the condenser 3 is provided with a fan 11 for blowing air and a temperature detection unit 12 for measuring the intake air temperature. The temperature detection unit 12 is provided at a position where the temperature of the air sucked by the fan 11 can be measured, and is electrically connected to the control unit 8. The temperature detection unit 12 measures the temperature of the intake air by the fan 11 and outputs the measured air temperature to the control unit 8. Note that various types of temperature sensors can be used as the temperature detection unit 12.

  The control unit 8 includes a microcomputer that centrally controls each unit, a storage unit that stores various types of information and various programs, and an operation unit that receives operations from an operator. Note that a memory, a hard disk drive (HDD), or the like is used as the storage unit. The control unit 8 controls the on-off valves 9a, 9b, and 9c in addition to the compressor 2 and the fan 11 based on various information and various programs.

  Next, the refrigerant leak detection process performed by the refrigeration apparatus 1 will be described. In addition, the control part 8 of the refrigeration apparatus 1 performs a coolant leak detection process based on various programs and various information.

  As shown in FIG. 2, first, the control unit 8 determines whether or not the operating condition is compatible with the pump-down operation start condition (step S1). For example, the control unit 8 determines whether or not the operation condition is adapted to the pump-down operation start condition by determining whether or not the current time has reached a predetermined time.

  That is, the pump-down operation for refrigerant leakage determination is set to be executed once a day in a time when the environment around the load-side evaporator 6 such as a showcase is stable. For example, the pump-down operation is performed once a day at a predetermined time of 7:00 or midnight. This execution time is preset in the storage unit.

  If it is determined in step S1 that the operating conditions are compatible with the pump down operation start conditions (YES in step S1), the refrigerant down determination pump down operation is started (step S2). The pump down time until the compressor 2 is stopped is measured (step S3). The control unit 8 has a timer function and can measure the pump down time.

  In step S2, the control unit 8 forcibly opens the on-off valves 9b and 9c before each evaporator 6 (that is, before each decompression unit 5), and then forcibly closes the on-off valve 9a after the receiver 4. . Thereby, a refrigerant | coolant is once supplied to each evaporator 6 from the liquid receiver 4, and after that, the refrigerant | coolant outflow from the liquid receiver 4 is stopped, and the refrigerant | coolant supply to each evaporator 6 is stopped.

  Moreover, in step S3, the control part 8 calculates | requires the pump down time until the compressor 2 stops from the pump down driving | operation start with a timer. At this time, the compressor 2 stops when the refrigerant pressure on the low pressure side becomes a predetermined value or less. That is, in the pump-down operation, when the control unit 8 determines that the detected refrigerant pressure has become lower than a predetermined value according to the low-pressure side refrigerant pressure detected by the pressure detection unit 10, for example, Stop. At this time, the control unit 8 functions as a low pressure switch together with the pressure detection unit 10 (low pressure cut function).

  After measuring the pump down time in step S3, the control unit 8 determines whether or not the current season is spring or autumn (step S4), and determines that the current season is not spring or autumn (NO in step S4). Next, it is determined whether or not the current season is summer (step S5). If it is determined that the current season is not summer (NO in step S5), it is determined that the current season is winter (step S5). Step S6). The control unit 8 has a calendar function, and can grasp the current date, date and time.

  If it is determined that the current season is spring or autumn (YES in step S4), it is determined whether the pump down time is smaller than a predetermined set value T1 (step S7), and the current season is summer. If it is determined (YES in step S5), it is determined whether or not the pump down time is smaller than a predetermined set value T2 (step S8), and after determining in step S6 that the current season is winter. Determines whether the pump-down time is smaller than a predetermined set value T3 (step S9).

  When it is determined that the pump down time is smaller than the predetermined set value T1 (YES in step S7), when it is determined that the pump down time is smaller than the predetermined set value T2 (YES in step S8), or when the pump is down If it is determined that the time is smaller than the predetermined set value T3 (YES in step S9), it is detected that there is a refrigerant leak (existing refrigerant leak) (step S10), and the process returns to step S1. On the other hand, if it is determined that the pump-down time is not smaller than the predetermined set values T1, T2, T3, the refrigerant leakage is regarded as no and the process returns to step S1. If it is detected in step S10 that the refrigerant has leaked, the fact that the refrigerant has leaked (presence of the refrigerant leak) is notified by a notification device such as a lamp, sound, or indicator.

  In such a refrigerant leak detection process, the refrigerant outflow from the receiver 4 is stopped, the pump down time from the stop of the refrigerant outflow until the compressor 2 is stopped is obtained, and the calculated pump down time is reached. Accordingly, the presence or absence of refrigerant leakage is determined. As a result, it is possible to detect a refrigerant leak using the pump down time without requiring an expensive sensor, a complicated system, complicated measurement software, and the like, and further, it is possible to grasp a sign of the refrigerant leak. . As a result, it is possible to detect refrigerant leakage at an early stage with a simple configuration at low cost.

  Here, the aforementioned setting values T1, T2, and T3 are different numerical values, and are set in advance in the storage unit of the control unit 8 as setting information. The set value T1 is a set value of pump down time when the season is spring or autumn, the set value T2 is a set value of pump down time when the season is summer, and the set value T3 is set when the season is winter. This is the set value for the pump down time in some cases.

  Thus, the set values T1, T2, and T3 are set in the storage unit for each season. However, since the pump down time is likely to change depending on the environment, the set values T1, T2, and T3 are the actual pump down times (initial information and Is corrected by the control unit 8. Note that the set values T1, T2, and T3 may be set for each installation site (pipe length) of the refrigeration apparatus 1 other than for each season.

  For example, in the above-described correction, a time difference between the set values T1, T2, and T3 set in the storage unit and an actually measured pump down time in a state where no refrigerant leakage occurs such as a test run is obtained, and the time difference is used. The set values T1, T2, and T3 set in the storage unit may be corrected. Alternatively, the time difference is stored in the storage unit, and when performing the coolant leakage detection process, the time difference is used to correct the set values T1, T2, and T3 set in the storage unit before use. Also good. Further, the intake air temperature in the vicinity of the condenser 3 may be detected by the temperature detection unit 12, and the set values T1, T2, and T3 set in the storage unit may be corrected based on the detected intake air temperature.

  By such correction, the set values T1, T2, and T3 of the pump down time for each season are corrected according to the ambient environment (for example, ambient temperature, pipe length, etc.) of the actual installation location. Refrigerant leakage can be detected using settings corresponding to the actual installation site, and refrigerant leakage can be detected more reliably. In particular, the installation environment (ambient temperature) of the condenser 3 differs depending on the setting site, for example, the influence of the western sun and the on-site conditions such as poor ventilation and easy exhaustion. It is preferable to correct the set values T1, T2, and T3 for each season by detecting the temperature.

  As described above, according to the embodiment of the present invention, the on-off valve 9a is controlled to stop the refrigerant outflow from the liquid receiver 4, and the pump down time from the stop of the refrigerant outflow until the compressor 2 stops. It is possible to detect refrigerant leakage without requiring expensive sensors, complicated systems, complicated measurement software, etc., by determining whether there is refrigerant leakage according to the calculated pump down time. It is possible to get a sign of refrigerant leakage. As a result, it is possible to detect refrigerant leakage at an early stage with a simple configuration at low cost. In particular, the pump down time described above was used for the same chain store where the number of showcases on the load side was determined as in stores such as convenience stores, and the piping distance for refrigerant was almost standardized in each store. Refrigerant leak detection is preferred.

  Further, immediately before closing the on-off valve 9a on the liquid receiver 4 side, the on-off valves 9b, 9c on the evaporator 6 side were closed by opening the on-off valves 9b, 9c on the evaporator 6 side. Even in this case, since the detection of the refrigerant leak is started after the refrigerant is supplied to the evaporator 6, the pump down time can be accurately obtained, and the refrigerant leak is reliably detected using the pump down time. Can do.

  In addition, setting values T1, T2, and T3 of the pump down time for each season (or each installation site) are stored, and from the stored setting values T1, T2, and T3 for each season (or each installation site) The set value is selected according to the season (or the current installation site), and the selected set value is compared with the determined pump down time to determine whether there is a refrigerant leak. Since the set value of the pump down time is selected and used according to the above, it is possible to reliably detect the refrigerant leakage even when using the pump down time that changes according to the season (or the installation site).

  Further, in a state where no refrigerant leaks, the refrigerant outflow from the liquid receiver 4 is stopped to determine the pump down time, and based on the obtained pump down time, every stored season (or every installation site) By correcting the set values T1, T2, and T3, the set value of the pump down time for each season (or for each installation site) according to the ambient environment (for example, ambient temperature, pipe length, etc.) of the actual installation location Will be corrected. Thereby, since it becomes possible to detect a refrigerant | coolant leak using the setting corresponding to an actual installation field, a refrigerant | coolant leak can be detected more reliably.

  In addition, once a day, at the predetermined time when the ambient environment of the load-side evaporator 6 is stable, the presence or absence of refrigerant leakage using the pump-down time is determined, so that the ambient environment on the load side (for example, ambient It is possible to prevent changes in temperature) from affecting the measurement of the pump down time. As a result, the pump down time can be accurately obtained, so that refrigerant leakage can be detected more reliably.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, some components may be deleted from all the components shown in the above-described embodiment. Furthermore, you may combine the component covering different embodiment suitably.

  For example, the refrigerant leak detection using the degree of superheat of the evaporator located at the end of the pipe or the temperature inside the showcase may be added to the refrigerant leak detection in the above-described embodiment. In this case, the reliability with respect to detection of refrigerant leakage can be improved.

DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 2 Compressor 3 Condenser 4 Liquid receiver 5 Depressurization part 6 Evaporator 7 Refrigerant piping 8 Control part 9a On-off valve 9b On-off valve 9c On-off valve 10 Pressure detection part 11 Fan 12 Temperature detection part

Claims (10)

A refrigeration apparatus comprising a compressor, a condenser, a liquid receiver, a decompression unit and an evaporator,
A refrigerant pipe for circulating the refrigerant by sequentially connecting the compressor, the condenser, the liquid receiver, the pressure reducing unit, and the evaporator;
An on-off valve provided in the middle of the refrigerant pipe and between the receiver and the evaporator to adjust the flow of the refrigerant from the receiver to the evaporator;
A pressure detection unit that detects the pressure of the decompressed refrigerant flowing through the refrigerant pipe after being decompressed by the decompression unit;
A controller that stops the compressor according to the pressure detected by the pressure detector;
With
The control unit controls the on-off valve to stop the refrigerant outflow from the receiver, obtain a pump down time from the stop of the refrigerant outflow until the compressor stops, and according to the obtained pump down time And determining whether or not there is a refrigerant leak from the refrigerant pipe . Two on-off valves are provided, one of the two on-off valves is a receiver-side on-off valve provided on the outlet side of the receiver, and the other of the two on-off valves is the evaporator Is an on-off valve on the evaporator side provided on the inlet side of
2. The refrigeration apparatus according to claim 1, wherein the control unit opens the on-off valve on the evaporator side immediately before closing the on-off valve on the receiver side.   The control unit stores a set value of the pump down time for each season, selects a set value according to the current season from the stored set value for each season, and obtains the selected set value. The refrigeration apparatus according to claim 1, wherein the presence or absence of the refrigerant leakage is determined by comparing with a pump down time.   The controller is configured to control the on-off valve to stop the refrigerant outflow from the liquid receiver to obtain the pump down time in a state where no refrigerant leak occurs, and based on the obtained pump down time, The refrigeration apparatus according to claim 3, wherein the stored set value for each season is corrected.   The said control part judges the presence or absence of the said refrigerant | coolant leakage using the said pump down time for the predetermined time when the surrounding environment of the said evaporator on the load side is stable once a day. Item 5. The refrigeration apparatus according to any one of Items 1 to 4. A refrigerant, a condenser, a liquid receiver, a decompression unit, and a evaporator are sequentially connected to the refrigerant pipe to detect the pressure of the decompressed refrigerant decompressed by the decompression unit, and the compression is performed according to the detected pressure. In the refrigeration system that stops the machine,
Stop the refrigerant outflow from the receiver, determine the pump down time from the stop of the refrigerant outflow until the compressor stops, and determine whether there is refrigerant leakage from the refrigerant pipe according to the determined pump down time A refrigerant leak detection method for a refrigeration apparatus.   Two on-off valves are provided between the receiver and the evaporator in the middle of the refrigerant pipe, and one of the two on-off valves is provided on the outlet side of the receiver If the other of the two on-off valves is an evaporator-side on-off valve provided on the inlet side of the evaporator, the evaporation is performed immediately before closing the receiver-side on-off valve. The refrigerant leakage detection method for a refrigeration apparatus according to claim 6, wherein the open / close valve on the side of the container is opened.   Store the set value of the pump down time for each season, select the set value according to the current season from the stored set values for each season, and compare the selected set value with the calculated pump down time. The refrigerant leak detection method for a refrigeration apparatus according to claim 6 or 7, wherein the presence or absence of the refrigerant leak is determined.   In a state where no refrigerant leaks, the refrigerant outflow from the receiver is stopped and the pump down time is obtained. Based on the obtained pump down time, the stored set value for each season is corrected. The refrigerant leakage detection method for a refrigeration apparatus according to claim 8, wherein:   10. The presence or absence of the refrigerant leakage using the pump-down time is determined once a day at a predetermined time when the ambient environment of the evaporator on the load side is stable. The refrigerant leak detection method of the refrigeration apparatus as described in any one.

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