JP5693328B2 - 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 refrigerator in which a supercoolable condenser and a liquid receiver are integrated, a decompression unit and an evaporator in the refrigeration apparatus, Refrigerant piping for circulating refrigerant by sequentially connecting a refrigerator, a decompression unit and an evaporator, a high pressure detecting unit for detecting the high pressure of the refrigerator, and a refrigerator outlet piping for detecting the piping temperature on the outlet side of the refrigerator The degree of supercooling, which is the temperature difference between the obtained condensing temperature and the piping temperature detected by the refrigerator outlet piping temperature detection unit, obtained from the high pressure detected by the temperature detection unit and the high pressure detection unit And a determination unit that determines the presence or absence of refrigerant leakage according to the determined degree of supercooling.

  According to a second aspect of the present invention, in the refrigeration apparatus according to the first aspect described above, a condenser outlet pipe temperature detector for detecting a pipe temperature on the outlet side of the condenser or a pipe temperature on the outlet side of the receiver. A receiver outlet pipe temperature detection unit that detects the pipe temperature detected by the condenser outlet pipe temperature detection unit or the judgment part when the high pressure detection unit cannot detect the high pressure. The pipe temperature detected by the receiver outlet pipe temperature detection unit is used as the condensation temperature.

  According to a third feature of the present invention, in the refrigeration apparatus according to the first or second feature described above, when a predetermined time has elapsed after the defrosting of the evaporator is completed, The high pressure is detected by the high pressure detector, the condensation temperature is calculated, the pipe temperature is detected by the refrigerator outlet pipe temperature detector, and the average value of the calculated condensation temperature and the detected pipe temperature are calculated and calculated. The temperature difference between the average value of the condensed condensation temperature and the calculated average value of the piping temperature is obtained as the degree of supercooling.

  According to a fourth feature of the present invention, in the refrigeration apparatus according to the first, second, or third feature described above, the determination unit stores a set value of the degree of supercooling for each season. A setting value is selected according to the current season from the setting values for each season, and the selected setting value is compared with the obtained degree of supercooling to determine the presence or absence of refrigerant leakage.

  According to a fifth feature of the present invention, in the refrigeration apparatus according to the fourth feature described above, the determination unit obtains the degree of supercooling in a state where refrigerant leakage has not occurred, and based on the obtained degree of supercooling, It is to correct the stored set value for each season.

  According to a sixth aspect of the present invention, in the refrigeration apparatus according to the fourth or fifth aspect, the air temperature detection unit that detects the intake air temperature around the condenser is provided, and the determination unit has a refrigerant leak. It is to correct the stored set value for each season based on the intake air temperature detected by the air temperature detection unit in a state where it has not occurred.

  According to a seventh feature of the present invention, in the refrigeration apparatus according to any one of the first to sixth features described above, the determination unit is configured to detect refrigerant leakage using the degree of supercooling once or a plurality of times a day. It is to determine the presence or absence.

  An eighth feature according to the present invention is a refrigerant leak detection method for a refrigeration apparatus, comprising: a refrigerator in which a compressor, a supercoolable condenser and a liquid receiver are integrated; and a decompression unit and an evaporator. In a refrigeration system equipped with refrigerant pipes that are connected sequentially, the high pressure of the refrigerator and the pipe temperature on the outlet side of the refrigerator are detected, the condensation temperature of the refrigerant is determined from the detected high pressure, and the obtained condensation temperature and the detected pipe temperature The degree of supercooling, which is a temperature difference from the above, is obtained, and the presence or absence of refrigerant leakage is determined according to the obtained degree of supercooling.

  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, when it is impossible to detect a high pressure, the pipe temperature or the receiving temperature at the outlet side of the condenser is not possible. The pipe temperature on the outlet side of the liquid device is detected, and the detected pipe temperature is used as the condensation temperature.

  According to a tenth feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to the eighth or ninth feature described above, when a predetermined time has elapsed after the defrosting of the evaporator is completed, the tenth feature is a predetermined interval. , The high pressure is detected to obtain the condensation temperature, the pipe temperature is detected, the average value of the obtained condensation temperature and the average value of the detected pipe temperature are calculated, and the calculated average value of the condensation temperature and the calculated pipe temperature are calculated. The temperature difference from the average value is obtained as the degree of supercooling.

  According to an eleventh feature of the present invention, in the refrigerant leakage detection method for a refrigeration apparatus according to the above-described eighth, ninth, or tenth feature, a set value of the degree of supercooling for each season is stored and stored. The setting value is selected according to the current season from the setting value for each season, and the selected setting value is compared with the obtained degree of supercooling to determine the presence or absence of refrigerant leakage.

  According to a twelfth feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to the eleventh feature described above, the degree of supercooling is obtained in a state where no refrigerant leaks, and based on the obtained degree of supercooling. It is to correct the stored set value for each season.

  According to a thirteenth feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to the eleventh or twelfth feature described above, an intake air temperature around the condenser is detected in a state where no refrigerant leak occurs. Based on the detected intake air temperature, the stored set value for each season is corrected.

  According to a fourteenth feature of the present invention, in the refrigerant leak detection method for a refrigeration apparatus according to any one of the eighth to thirteenth features, the refrigerant leak using the degree of supercooling once or a plurality of times a day. It is to determine whether or not.

  According to the first or eighth feature of the present invention, the refrigerant temperature and the pipe temperature are detected, and the degree of supercooling, which is a temperature difference between them, is obtained, and the refrigerant leakage is determined according to the obtained degree of supercooling. Presence or absence is determined. This makes it possible to detect refrigerant leakage using the degree of supercooling without requiring an expensive sensor, a complicated system, complicated measurement software, and the like, and it is possible to grasp 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.

  According to the second or ninth feature of the present invention, when it is impossible to detect the high pressure described above, the pipe temperature of the refrigerant pipe on the outlet side of the condenser 2b or the outlet side of the liquid receiver 2c The pipe temperature of the refrigerant pipe is detected, and the detected pipe temperature is used as the condensation temperature. As a result, even when the high pressure cannot be detected, it is possible to detect the refrigerant leakage and to grasp the sign, and to detect the refrigerant leakage at an early stage.

  According to the third or tenth feature of the present invention, the average value of the condensation temperature and the average value of the pipe temperature are calculated, and the temperature difference between the calculated average value of the condensation temperature and the average value of the pipe temperature is calculated. Calculated as the degree of supercooling. As a result, an accurate degree of supercooling can be obtained, so that the refrigerant leakage can be reliably detected using the degree of supercooling.

  According to the fourth or eleventh feature of the present invention, the set value of the degree of supercooling for each season is stored, and the set value is selected according to the current season from the stored set values for each season. Then, the selected set value is compared with the obtained degree of supercooling to determine whether or not there is a refrigerant leak. Thereby, since the set value of the degree of supercooling is selected and used according to the season, the refrigerant leakage can be reliably detected even when the degree of supercooling that changes depending on the season is used.

  According to the fifth or twelfth feature of the present invention, the degree of supercooling is obtained in a state where no refrigerant leaks, and the stored seasonal setting is based on the obtained degree of supercooling. The value is corrected. As a result, the set value of the degree of supercooling for each season is corrected according to the ambient environment (for example, ambient temperature, pipe length, etc.) in 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 sixth or thirteenth feature of the present invention, the intake air temperature is detected in a state where no refrigerant leaks, and the stored set value for each season is based on the intake air temperature. It is corrected. As a result, it is possible to detect the refrigerant leakage using the set value corresponding to the actual installation site. In particular, because the installation environment (ambient temperature) of the refrigerator varies depending on the setting site, the intake air temperature near the condenser varies depending on, for example, the influence of the western sun and on-site conditions such as poor ventilation and easy exhaust heat. It is preferable to correct the set value for each season by detecting.

  According to the seventh or fourteenth feature of the present invention, the presence / absence of refrigerant leakage using the degree of supercooling is determined once or a plurality of times a day. As a result, it is possible to more reliably detect refrigerant leakage, and it is possible to more reliably grasp a sign of refrigerant leakage, thereby improving device reliability.

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 refrigerator 2 that compresses and condenses refrigerant, a plurality of decompression units 3 that decompress the refrigerant, and a plurality that evaporates the decompressed refrigerant. The evaporator 4, the refrigerant pipe 5 that circulates the refrigerant by connecting these parts, and the control unit 6 that performs various controls are provided.

  The refrigerator 2 is a refrigerator in which a compressor 2a that compresses a refrigerant, a condenser 2b that condenses the compressed refrigerant, and a liquid receiver 2c that stores the condensed refrigerant are integrally formed. The condenser 2b of the refrigerator 2 includes a plurality of condensing portions 2b1 and 2b2 that are refrigerant circuits for condensing the refrigerant (two in FIG. 1), and is configured to be able to supercool the refrigerant.

  The condensing units 2b1 and 2b2 are connected by a refrigerant pipe 5 so that the refrigerant passes through the condensing unit 2b1 and then passes through the liquid receiver 2c and the condensing unit 2b2. Specifically, the outlet of the condenser 2b1 is connected to the inlet of the receiver 2c via the refrigerant pipe 5, and the inlet of the condenser 2b2 is connected to the outlet of the receiver 2c via the refrigerant pipe 5. Yes. Thereby, since the refrigerant | coolant which passed the condensation part 2b1 passes the condensation part 2b2 again, the condensation part 2b2 functions as a supercooling heat exchanger. In this way, the refrigerant (liquid refrigerant) passes through the condensing parts 2b1 and 2b2 of the condenser 2b and is cooled twice, so that the condensate temperature can be lowered and the supercooling can be greatly increased.

  The refrigerant pipe 5 is a flow path through which the refrigerant is circulated by sequentially connecting the compressor 2a, the condenser 2b, the liquid receiver 2c of the refrigerator 2, and the decompression units 3 and the evaporators 4 in order. It consists of piping such as pipes. With respect to the flow path of the refrigerant pipe 5, each decompression unit 3 and each evaporator 4 are a set of one decompression unit 3 and one evaporator 4 arranged in series, and each set is connected in parallel. Yes. For example, an expansion valve is used as the decompression unit 3.

  The refrigerant flowing through the refrigerant pipe 5 circulates through the refrigerant pipe 5 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 2a flows into the condenser 2b, is cooled by the condensing part 2b1 of the condenser 2b, releases the heat of condensation, and is liquefied to the liquid receiver 2c. Stored. This liquid receiver 2c absorbs the fluctuation | variation of the refrigerant | coolant amount in each evaporator 4 by load fluctuation | variation.

  Thereafter, the normal-temperature and high-pressure liquid refrigerant stored in the liquid receiver 2c is cooled again by the condensing part 2b2 of the condenser 2b and flows into each decompression part 3, and is decompressed by each decompression part 3 to lower the boiling point. It becomes a state. The low-temperature and low-pressure liquid refrigerant in this state is boiled and evaporated by each evaporator 4, and cools by removing the surrounding heat. The evaporated low-pressure gas refrigerant flows into the compressor 2a, is compressed by the compressor 2a, becomes a high-temperature high-pressure gas refrigerant that can be liquefied by air at normal temperature, and flows into the condenser 2b again.

  The refrigerant pipe 5 through which the refrigerant circulates is provided with a plurality of on-off valves 7a and 7b. Each on-off valve 7 a, 7 b is provided in the middle of the refrigerant pipe 5 and between the refrigerator 2 and each decompression unit 3. In particular, each of the on-off valves 7 a and 7 b is provided on the inlet side of the decompression unit 3 and in the vicinity of the inlet, and adjusts the refrigerant inflow to each decompression unit 3. As these on-off valves 7a and 7b, for example, electromagnetic valves are used. Each on-off valve 7 a, 7 b is electrically connected to the control unit 6, and its driving is controlled by the control unit 6.

  The refrigerant pipe 5 is a refrigeration that detects the refrigerant temperature of the refrigerant supercooled by the condenser 2b, that is, the pipe temperature on the outlet side of the refrigerator 2 (the pipe temperature of the refrigerant pipe 5 through which the liquid refrigerant passes). A machine outlet pipe temperature detector 8 is provided, and the pipe temperature of the refrigerant pipe 5 existing between the condenser 2b1 and the liquid receiver 2c, that is, the pipe temperature (gas and liquid on the outlet side of the condenser 2b1). A condenser outlet pipe temperature detection unit 9 is provided for detecting the refrigerant temperature of the refrigerant pipe 5 through which the refrigerant in a mixed state passes.

  In addition, the pipe temperature of the refrigerant pipe 5 existing between the liquid receiver 2c and the condensing part 2b2, that is, the pipe temperature on the outlet side of the liquid receiver 2c (the refrigerant pipe through which the refrigerant in a state where gas and liquid are mixed passes. 5 is provided with a receiver outlet pipe temperature detection unit 10 for detecting a high pressure pressure detection unit 11 for detecting a high pressure (condensation temperature) on the outlet side of the compressor 2a. Yes.

  The refrigerator outlet pipe temperature detector 8 is provided on the outlet side of the refrigerator 2 and in the vicinity of the outlet, and is electrically connected to the controller 6. The refrigerator outlet piping temperature detection unit 8 measures the piping temperature on the outlet side of the refrigerator 2 and outputs the measured piping temperature to the control unit 6. Various types of temperature sensors can be used as the refrigerator outlet pipe temperature detection unit 8.

  The condenser outlet pipe temperature detector 9 is provided on the outlet side of the condenser 2 b 1 of the condenser 2 b and in the vicinity of the outlet, and is electrically connected to the controller 6. The condenser outlet pipe temperature detector 9 measures the pipe temperature of the refrigerant pipe 5 on the outlet side of the condenser 2 b 1 and outputs the measured pipe temperature to the controller 6. Note that various types of temperature sensors can be used as the condenser outlet pipe temperature detection unit 9.

  The liquid receiver outlet pipe temperature detection unit 10 is provided on the outlet side of the liquid receiver 2 c and in the vicinity of the outlet, and is electrically connected to the control unit 6. The liquid receiver outlet pipe temperature detection unit 10 measures the pipe temperature of the refrigerant pipe 5 on the outlet side of the liquid receiver 2 c and outputs the measured pipe temperature to the control unit 6. Various types of temperature sensors can be used as the receiver outlet piping temperature detection unit 10.

  The high-pressure detector 11 is provided on the outlet side of the compressor 2 a and in the vicinity of the outlet, and is electrically connected to the controller 6. The high pressure detector 11 measures the high pressure of the refrigerator 2 and outputs the measured high pressure to the controller 6. Note that various types of pressure sensors can be used as the high pressure detector 11.

  Further, the condenser 2b is provided with a fan 12 for blowing air and an air temperature detecting unit 13 for measuring the intake air temperature. The air temperature detection unit 13 is provided at a position where the temperature of the air sucked by the fan 12 can be measured, and is electrically connected to the control unit 6. The air temperature detection unit 13 measures the temperature of the intake air by the fan 12 and outputs the measured air temperature to the control unit 6. As the air temperature detection unit 13, various types of temperature sensors can be used.

  The control unit 6 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 controller 6 controls the on-off valves 7a and 7b in addition to the compressor 2a and the fan 12 based on various information and various programs. Furthermore, the control unit 6 functions as a determination unit that determines the presence or absence of refrigerant leakage.

  Next, the refrigerant leak detection process performed by the refrigeration apparatus 1 will be described. In addition, the control part 6 of the freezing apparatus 1 performs a refrigerant | coolant leak detection process based on various programs and various information.

  As shown in FIG. 2, first, the control unit 6 determines whether or not the operating condition matches the supercooling degree determination start condition (step S1). For example, the control unit 6 determines whether or not the operation condition is adapted to the supercooling degree determination start condition by determining whether or not a predetermined time has elapsed after the defrosting of the evaporator 4 is completed. to decide. In addition, the control part 6 has a timer function, and can measure the elapsed time after defrosting is complete | finished.

  Here, the fixed time is a time when the inside temperature of the showcase on the load side corresponding to the evaporator 4 becomes steady after defrosting, and is set in advance in the storage unit. The defrosting operation (defrosting operation) is an operation for performing defrosting (defrosting) in which frost adhering to the evaporator 4 of the showcase is melted by a defrosting heater. At this time, the on-off valves 7a and 7b corresponding to the showcase performing the defrosting operation are closed, and the refrigerant supply to the evaporator 4 corresponding to the showcase is stopped. The defrost time concerning this defrost is set to the memory | storage part within the range from tens of minutes to several hours, for example. The defrosting operation is set to be executed at the same time, for example, every day several times a day.

  After such a defrosting operation, a pull-down that is a return operation is always executed. This pull-down is to return the internal temperature raised by defrosting to a predetermined set temperature, and the pull-down time is a time until the internal temperature reaches the predetermined set temperature. In the pull-down, in order to shorten the pull-down time, and in order to prevent the quality of the product to be cooled, the refrigerator 2 normally performs a cooling operation at full operation, and the internal temperature is stabilized at a predetermined set temperature. Return to steady operation. The timing of returning to the steady operation is the timing of starting the supercooling degree determination.

  If it is determined in step S1 that the operating condition is suitable for the supercooling degree determination start condition (YES in step S1), the refrigerant condensing temperature is calculated from the high pressure detected by the high pressure detector 11. Then, the degree of supercooling, which is the temperature difference between the determined condensation temperature and the piping temperature detected by the refrigerator outlet piping temperature detection unit 8, is determined (step S2).

  Here, when obtaining the degree of supercooling, the control unit 6 detects the high pressure by the high pressure detection unit 11 at a predetermined interval preset in the storage unit to obtain the condensation temperature, and further, the refrigerator outlet The pipe temperature is detected by the pipe temperature detector 8, and then the condensation temperature obtained from the high pressure detected at a predetermined interval is summed and divided by the number of detections, and the average value is calculated. Similarly, it is detected at the predetermined interval. The pipe temperatures are summed and divided by the number of detections to calculate the average value. Finally, the temperature difference between the calculated average condensation temperature and the calculated pipe temperature average is obtained as the degree of supercooling.

  However, when it is impossible to detect the high pressure by the high pressure detector 11, the pipe temperature detected by the condenser outlet pipe temperature detector 9 or the receiver outlet pipe temperature detector 10 The detected pipe temperature is used as the condensation temperature by the same average value calculation processing as described above.

  After calculating the degree of supercooling in step S2, the control unit 6 determines whether or not the current season is spring or autumn (step S3), and determines that the current season is not spring or autumn (NO in step S3). Next, it is determined whether or not the current season is summer (step S4). If it is determined that the current season is not summer (NO in step S4), it is determined that the current season is winter (step S4). Step S5). The control unit 6 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 S3), it is determined whether the degree of supercooling is smaller than a predetermined set value T1 (step S6), and the current season is summer. If it is determined (YES in step S4), it is determined whether the degree of supercooling is smaller than a predetermined set value T2 (step S7), and after determining that the current season is winter in step S5. Determines whether or not the degree of supercooling is smaller than a predetermined set value T3 (step S8).

  When it is determined that the degree of supercooling is smaller than the predetermined set value T1 (YES in step S6), when it is determined that the degree of supercooling is smaller than the predetermined set value T2 (YES in step S7), or supercooling If it is determined that the degree is smaller than the predetermined set value T3 (YES in step S8), it is detected that there is a refrigerant leak (existing refrigerant leak) (step S9), and the process returns to step S1. On the other hand, when it is determined that the degree of supercooling is not smaller than the predetermined set values T1, T2, and T3, the refrigerant leakage is not performed and the process returns to step S1. If it is detected in step S9 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 high-pressure pressure of the refrigerator 2 is detected by the high-pressure detection unit 11, the condensation temperature of the refrigerant is obtained from the high-pressure pressure, and the refrigerant pipe 5 through which the supercooled refrigerant passes. Is detected by the refrigerator outlet pipe temperature detection unit 8. Thereafter, the degree of supercooling, which is the temperature difference between the condensation temperature and the pipe temperature, is obtained, and the presence or absence of refrigerant leakage is determined according to the obtained degree of supercooling. This makes it possible to detect refrigerant leakage using the degree of supercooling without requiring an expensive sensor, a complicated system, complicated measurement software, and the like, and it is possible to grasp 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. Note that, in the cycle in which supercooling is performed as described above, a noticeable tendency that supercooling cannot be obtained at all when the amount of refrigerant is insufficient appears, so pay attention to this, and a method for detecting refrigerant leakage using the degree of supercooling Is used.

  Here, the setting values T1, T2, and T3 described above are different from each other, and are set as setting information in the storage unit of the control unit 6 in advance. The setting value T1 is a setting value of the degree of supercooling when the season is spring or autumn, the setting value T2 is a setting value of the degree of supercooling when the season is summer, and the setting value T3 is a setting value when the season is winter This is the set value of the degree of supercooling in some cases.

  Thus, the set values T1, T2, and T3 are set in the storage unit for each season. However, since the degree of supercooling (supercooling temperature) is likely to change depending on the environment, the set values T1, T2, and T3 are actually measured supercooling values measured by the above-described processing in a state where no refrigerant leakage such as trial operation occurs. It is corrected by the control unit 6 using the degree (referred to as initial information). 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 temperature difference between the set values T1, T2, and T3 set in the storage unit and an actually measured degree of supercooling in a state where refrigerant leakage does not occur, such as a trial run, is obtained, and the temperature difference is calculated. It is also possible to correct the set values T1, T2 and T3 set in the storage unit. Alternatively, the temperature difference is stored in the storage unit, and when the refrigerant leakage detection process is performed, the temperature difference is used to correct the set values T1, T2, and T3 set in the storage unit before use. Anyway. Further, the intake air temperature in the vicinity of the condenser 2b may be detected by the air temperature detection unit 13, 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, T3 of the degree of supercooling 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, since the installation environment (ambient temperature) of the refrigerator 2 varies depending on the setting site, for example, the influence of the western sun and on-site conditions such as poor ventilation and easy exhaustion, so the suction near the condenser 2b It is preferable to detect the air temperature and correct the set values T1, T2, and T3 for each season.

  As described above, according to the embodiment of the present invention, the condensation temperature of the refrigerant is obtained from the high pressure detected by the high pressure detector 11 and is detected by the obtained condensation temperature and the refrigerator outlet pipe temperature detector 8. By determining the degree of supercooling, which is the temperature difference from the piping temperature, and determining whether there is a refrigerant leak according to the calculated degree of supercooling, there is no need for expensive sensors, complicated systems, complicated measurement software, etc. Thus, it is possible to detect refrigerant leakage, and it is possible to grasp 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 above-mentioned degree of supercooling 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, when it is impossible to detect the high pressure described above, the piping temperature on the outlet side of the condenser 2b or the piping temperature on the outlet side of the liquid receiver 2c is detected, and the detected piping temperature is used as the condensation temperature. By using it, even when a high pressure cannot be detected, it is possible to detect a refrigerant leak and grasp a sign, and to detect a refrigerant leak at an early stage.

  In addition, the average value of the above-mentioned condensation temperature and the average value of the pipe temperature are calculated, and the temperature difference between the calculated average value of the condensation temperature and the average value of the pipe temperature is obtained as the degree of supercooling. Since it becomes possible to obtain the degree of cooling, it is possible to reliably detect refrigerant leakage using the degree of supercooling.

  Further, the setting values T1, T2, and T3 of the degree of supercooling for each season (or each installation site) are stored, and the current setting values T1, T2, and T3 for each season (or each installation site) are stored. A set value is selected according to the season (or the current installation site), and the selected set value is compared with the obtained supercooling degree to determine whether there is a refrigerant leak. Accordingly, since the set value of the degree of supercooling is selected and used, the refrigerant leakage can be reliably detected even when the degree of supercooling that changes according to the season (or the installation site) is used.

  Further, the degree of supercooling is obtained in a state where no refrigerant leaks, and the stored set values T1, T2, and T3 for each season (or each installation site) are corrected based on the obtained degree of supercooling. As a result, the set value of the degree of supercooling for each season (or for each installation site) is corrected according to the ambient environment (for example, ambient temperature, pipe length, etc.) of the actual installation location. 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.

  Further, the intake air temperature is detected by the air temperature detector 13 in a state where no refrigerant leaks, and the stored set value T1 for each season (or for each installation site) is stored based on the detected intake air temperature. , T2 and T3 can be corrected to detect refrigerant leakage using a set value corresponding to the actual installation site. In particular, since the installation environment (ambient temperature) of the refrigerator 2 varies depending on the setting site, it is preferable to detect the intake air temperature in the vicinity of the condenser 2b and correct the set values T1, T2, and T3 for each season.

  In addition, it is possible to detect refrigerant leakage more reliably by determining the presence or absence of refrigerant leakage using the degree of supercooling once or multiple times a day, and more reliably predict refrigerant leakage. Since it becomes possible to grasp, apparatus reliability can be improved.

  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.

  Further, in the above-described embodiment, the number of condensing parts 2b1 and 2b2 provided in the condenser 2b is not limited to two as shown in FIG. 1, and the number is not limited, and the condenser 2b can be supercooled. It only has to be configured.

DESCRIPTION OF SYMBOLS 1 Refrigerating device 2 Refrigerator 2a Compressor 2b Condenser 2b1 Condensing part 2b2 Condensing part 2c Receiving device 3 Decompression part 4 Evaporator 5 Refrigerant piping 6 Control part (determination part)
7a On-off valve 7b On-off valve 8 Refrigerator outlet piping temperature detection unit 9 Condenser outlet piping temperature detection unit 10 Receiver receiver piping temperature detection unit 11 High pressure detection unit 12 Fan 13 Air temperature detection unit

Claims (12)

A refrigeration apparatus comprising a compressor, a refrigerator in which a supercoolable condenser and a liquid receiver are integrated, a decompression unit and an evaporator,
A refrigerant pipe for sequentially circulating the refrigerant by connecting the refrigerator, the decompression unit and the evaporator sequentially;
A high-pressure detector that detects the high-pressure of the refrigerator;
A refrigerator outlet pipe temperature detection unit for detecting a pipe temperature on the outlet side of the refrigerator;
The supercooling is a temperature difference between the determined condensation temperature and the piping temperature detected by the refrigerator outlet piping temperature detection unit from the high pressure detected by the high pressure detection unit. A determination unit that determines the degree of refrigerant leakage according to the obtained degree of supercooling,
Equipped with a,
The determination unit stores a set value of the degree of supercooling for each season, and selects the set value of the degree of supercooling according to the current season from the set value of the degree of supercooling for each stored season and refrigeration apparatus which is characterized that you determine the presence or absence of the refrigerant leak by comparing the degree of supercooling obtained a set value of the supercooling degree selected. A condenser outlet pipe temperature detector for detecting the pipe temperature on the outlet side of the condenser or a receiver outlet pipe temperature detector for detecting a pipe temperature on the outlet side of the receiver;
The determination unit is configured to detect the pipe temperature detected by the condenser outlet pipe temperature detection unit or the receiver outlet pipe temperature detection unit when the high pressure cannot be detected by the high pressure detection unit. The refrigeration apparatus according to claim 1, wherein the pipe temperature detected by the method is used as the condensation temperature.   The determination unit detects the high pressure by the high pressure detection unit at a predetermined interval when a predetermined time has elapsed after the defrosting of the evaporator is completed, obtains the condensation temperature, and outputs the refrigerator outlet The pipe temperature detection unit detects the pipe temperature, calculates the average value of the calculated condensation temperature and the average value of the detected pipe temperature, and calculates the calculated average value of the condensation temperature and the calculated average value of the pipe temperature. The refrigeration apparatus according to claim 1, wherein the temperature difference is calculated as the degree of supercooling. The determination unit obtains the degree of supercooling in a state where refrigerant leakage has not occurred, and corrects the stored setting value of the degree of supercooling for each season based on the obtained degree of supercooling. 4. The refrigeration apparatus according to claim 1, 2, or 3. An air temperature detector for detecting the intake air temperature around the condenser;
The determination unit, in a state where refrigerant leakage has not occurred, said detected by the air temperature detecting unit based on the intake air temperature, corrects the degree of supercooling of the set value of each seasonal that remembers The refrigeration apparatus according to claim 1, 2, 3 or 4. Before SL determination unit may include one or more times a day, the claim 1, 2, 3, characterized in that performing the supercooling degree judged of whether the refrigerant leakage using, 4 or 5 refrigeration system according . In a refrigeration apparatus comprising a compressor, a refrigerator in which a supercoolable condenser and a liquid receiver are integrated, and a refrigerant pipe that sequentially connects a decompression unit and an evaporator,
The high pressure of the refrigerator and the piping temperature on the outlet side of the refrigerator are detected, the condensation temperature of the refrigerant is obtained from the detected high pressure, and the temperature difference between the obtained condensation temperature and the detected piping temperature Obtaining a certain degree of supercooling, and determining the presence or absence of refrigerant leakage according to the obtained degree of supercooling,
In the step of determining the presence or absence of the refrigerant leakage, a set value of the degree of supercooling for each season is stored, and the setting value of the degree of supercooling is set according to the current season from the stored value of the degree of supercooling for each season. A refrigerant leak detection method for a refrigeration apparatus, comprising: selecting a set value and comparing the selected set value of the degree of supercooling with the calculated degree of supercooling to determine whether or not the refrigerant leaks . When it is impossible to detect the high pressure, the piping temperature on the outlet side of the condenser or the piping temperature on the outlet side of the receiver is detected, and the detected piping temperature is used as the condensation temperature. The refrigerant leak detection method for a refrigeration apparatus according to claim 7 . When a definite period of time has elapsed after the defrosting of the evaporator is completed, the condensation pressure is detected by detecting the high pressure at predetermined intervals, the pipe temperature is detected, and the average value of the determined condensation temperatures. and it calculates an average value of the detected the pipe temperature, the temperature difference between the average value of the calculated the calculated average value of the condensing temperature the pipe temperature and obtaining as the degree of supercooling claim 7 or The refrigerant leak detection method for a refrigeration apparatus according to claim 8. The supercooling degree is obtained in a state where no refrigerant leaks, and the stored setting value of the supercooling degree for each season is corrected based on the obtained supercooling degree. The refrigerant leak detection method for a refrigeration apparatus according to 7, 8 or 9. Detecting the intake air temperature around the condenser in the absence of refrigerant leakage, and correcting the stored setting value of the degree of supercooling for each season based on the detected intake air temperature The refrigerant leakage detection method for a refrigerating apparatus according to claim 7, 8 , 9, or 10. The refrigerant leak detection method for a refrigeration apparatus according to claim 7, 8, 9, 10, or 11 , wherein the presence or absence of the refrigerant leak is determined using the degree of supercooling once or a plurality of times a day .

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