JP5623366B2 - Refrigerant leak detection method and refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigerant leak detection method in a refrigeration cycle having a compressor, a condenser, an expansion valve, and an evaporator, and a refrigeration facility having a refrigerant leak detection means for the refrigeration cycle.

  In order to detect a refrigerant leak, for example, in Patent Document 1, an oxygen concentration sensor and a refrigerant concentration sensor for detecting a leaked refrigerant are provided in each of an open showcase, a refrigerator, a freezer, and the like that are collectively managed by a monitor control panel. It is installed. The sensor is disposed close to the refrigerant pipe, for example. In Patent Document 2, an auxiliary tank is added to the side of a liquid receiving tank that stores refrigerant liquefied through a condenser, and a float type level sensor for measuring the liquid level of the refrigerant is installed in the auxiliary tank. Yes. By comparing the liquid level measured by the level sensor with the normal liquid level, a decrease in the amount of refrigerant, that is, refrigerant leakage is detected.

JP 2002-195718 (paragraph numbers 0010 to 0011) Japanese Patent Laid-Open No. 10-103820 (paragraph numbers 0013 to 0014)

  The refrigerant leak detection method of Patent Document 1 requires an oxygen concentration sensor and a refrigerant concentration sensor for detecting the leaked refrigerant, and the refrigerant leak detection method of Patent Document 2 is a level for measuring the liquid level of the refrigerant. A sensor and an auxiliary tank are required, and in either case, there is a disadvantage that the cost increases. In addition, when adding a refrigerant leak detection means to an existing refrigeration apparatus, it is necessary to install the above-described sensor or the like in each showcase or each liquid receiving tank, and much labor is required for the installation work.

  An object of the present invention is a refrigerant leakage detection method that can be implemented at low cost and can be equally applied to existing refrigeration equipment, and refrigeration and refrigeration provided with this kind of refrigerant leakage detection means. To provide facilities.

  The present invention relates to a method for detecting refrigerant leakage in a refrigeration cycle having a compressor 17, a condenser 18, an expansion valve 15 and an evaporator 14. Based on the indoor temperature C0 of the cooling device 9 cooled by the evaporation of the refrigerant in the evaporator 14, the superheat degree SH of the refrigerant at the outlet of the evaporator 14, and the valve opening OP of the expansion valve 15, the presence or absence of refrigerant leakage is determined. It is characterized by doing.

  A determination period having a predetermined time width is set, and the presence or absence of refrigerant leakage is determined for each determination period. Possible refrigerant leakage during the target determination period based on the values of the room temperature C0, the superheat degree SH, and the valve opening OP measured during the determination period, ie, the target determination period, for determining whether there is refrigerant leakage Based on the short-term determination D2 for determining the nature and the measured values of the indoor temperature C0, the superheat degree SH, and the valve opening OP in the continuous period from the determination period to the target determination period by a predetermined time before the target determination period, Long-term determination D3 for determining the possibility of refrigerant leakage in the target determination period.

  When it is determined that there is a possibility of refrigerant leakage in both the short-term determination D2 and the long-term determination D3, it is determined that refrigerant leakage has occurred during the target determination period.

  When the state in which the valve opening degree OP is equal to or greater than the threshold value continues for a certain time or longer within the target determination period, a valve opening abnormality determination D1 is determined that determines that there is a possibility of refrigerant leakage in the target determination period. When it is determined that there is a possibility of refrigerant leakage in all of the valve opening abnormality determination D1, the short-term determination D2, and the long-term determination D3, it is determined that the refrigerant leakage has occurred during the target determination period.

  When the cooling device 9 or the control panel 4 that monitors the cooling device 9 is in a state where the valve opening OP is equal to or greater than the threshold value, the valve opening abnormality alarm is generated. The valve opening abnormality determination D1 is performed with reference to the occurrence history of the valve opening abnormality alarm within the target determination period, and when it is determined that there is a possibility of refrigerant leakage in the valve opening abnormality determination D1, the short-term determination D2 And long-term determination D3 is performed.

The short-term determination D2 is [1] the number of measured values of the valve opening OP that are equal to or greater than the threshold among the measured values of the valve opening OP [2] the sum or average of the measured values of the valve opening OP [3] ] Sum or average of measured values of superheat degree SH [4] Step S2 for calculating the number of measured values of room temperature C0 that are equal to or greater than the threshold value, and setting reference values for each of [1] to [4] Step S3, step S4 for calculating the ratio of each value of [1] to [4] with respect to the reference value in the target determination period as a change rate, and each change rate of [1] to [4] as a threshold value. Step S5 to be compared is included. In the long-term determination D3, the change rates of [1] to [4] in each determination period constituting the continuous period are totaled to calculate the change rate integral, and each change of [1] to [4] And step S7 for comparing the rate integral with a threshold value. The reference value in the short-term determination D2 is set based on the measured values of the room temperature C0, the superheat degree SH, and the valve opening OP in a reference period that is a predetermined time before the target determination period. The end point of the reference period is set in the vicinity of the start point of the continuous period in the long-term determination D3.

  The present invention also includes a refrigeration cycle having a compressor 17, a condenser 18, an expansion valve 15, and an evaporator 14, a cooling device 9 that is cooled by evaporation of the refrigerant in the evaporator 14, and a refrigerant leak detection means for the refrigeration cycle. It relates to the refrigeration equipment provided with. The refrigerant leakage detection means is connected to the control server 4 that monitors and controls the operating state of the cooling device 9, the data server 5 that transmits and receives the operation data of the cooling device 9 integrated in the control panel 4, and the data server 5. Terminal device 6. A program for determining the presence or absence of refrigerant leakage based on the indoor temperature C0 of the cooling device 9 included in the operation data, the degree of superheat SH of the refrigerant at the outlet of the evaporator 14, and the valve opening OP of the expansion valve 15, It is mounted on the terminal device 6.

  The program of the terminal device 6 sets a determination period having a predetermined time width, and determines whether or not there is a refrigerant leak for each determination period. A short-term determination D2 for determining the possibility of refrigerant leakage in the target determination period based on each value of the room temperature C0, the superheat degree SH, and the valve opening OP measured during the period, and a predetermined time longer than the target determination period A long-term determination D3 that determines the possibility of refrigerant leakage in the target determination period based on the measured values of the room temperature C0, the superheat degree SH, and the valve opening OP in the continuous period from the previous determination period to the target determination period. including.

  The program of the terminal device 6 determines that refrigerant leakage has occurred during the target determination period when it is determined that there is a possibility of refrigerant leakage in both the short-term determination D2 and the long-term determination D3.

  The program of the terminal device 6 determines that there is a possibility of refrigerant leakage in the target determination period when the state where the valve opening OP is equal to or greater than the threshold value continues for a certain time or longer within the target determination period. When it is determined that there is a possibility of refrigerant leakage in all of the valve opening abnormality determination D1, the short-term determination D2, and the long-term determination D3, including the abnormality determination D1, it is determined that the refrigerant leakage has occurred.

  In the control panel 4, when the state where the valve opening OP is equal to or greater than the threshold value continues for a certain time or longer, a valve opening abnormality alarm is generated. The program of the terminal device 6 performs the valve opening abnormality determination D1 with reference to the occurrence history of the valve opening abnormality alarm within the target determination period, and it is determined that there is a possibility of refrigerant leakage in the valve opening abnormality determination D1. If short-term determination D2 and long-term determination D3 are performed.

The short-term determination D2 is [1] the number of measured values of the valve opening OP that are equal to or greater than the threshold among the measured values of the valve opening OP [2] the sum or average of the measured values of the valve opening OP [3] ] Sum or average of measured values of superheat degree SH [4] Step S2 for calculating the number of measured values of room temperature C0 that are equal to or greater than the threshold value, and setting reference values for each of [1] to [4] Step S3, step S4 for calculating the ratio of each value of [1] to [4] with respect to the reference value in the target determination period as a change rate, and each change rate of [1] to [4] as a threshold value. Step S5 to be compared is included. In the long-term determination D3, the change rates of [1] to [4] in each determination period constituting the continuous period are totaled to calculate the change rate integral, and each change of [1] to [4] And step S7 for comparing the rate integral with a threshold value. The reference value in the short-term determination D2 is set based on the measured values of the room temperature C0, the superheat degree SH, and the valve opening OP in a reference period that is a predetermined time before the target determination period. The end point of the reference period is set in the vicinity of the start point of the continuous period in the long-term determination D3.

  In the refrigerant leak detection method according to the present invention, based on the indoor temperature C0 of the cooling device 9 cooled by the evaporator 14, the superheat degree SH of the refrigerant at the outlet of the evaporator 14, and the valve opening OP of the expansion valve 15, Judgment was made on the presence or absence of refrigerant leakage. When refrigerant leakage occurs in the refrigeration cycle and the amount of refrigerant decreases, the cooling efficiency in the cooling device 9 decreases, so the room temperature C0 tends to be higher than normal. Further, when the amount of refrigerant decreases, the amount of heat exchange per unit amount of refrigerant in the evaporator 14 increases, so the degree of superheat SH tends to be higher than normal. Further, when the amount of refrigerant decreases, the opening degree OP of the expansion valve 15 tends to be higher than that in the normal state in order to secure the refrigerant flow rate in the evaporator 14. As described above, when the refrigerant amount in the refrigeration cycle decreases, the indoor temperature C0, the superheat degree SH, and the valve opening degree OP tend to show values different from normal values. Based on these values, the presence or absence of refrigerant leakage is determined. be able to.

  As described above, in the refrigerant leak detection method according to the present invention, the refrigerant leak is detected based on the room temperature C0, the superheat degree SH, and the valve opening OP. There is no need to provide a sensor, and the cost can be reduced accordingly. Furthermore, the refrigerant leak detection method according to the present invention can be introduced into existing refrigeration and refrigeration equipment with less effort without requiring a sensor installation operation as in the prior art.

  Based on the short-term determination D2 that determines the possibility of refrigerant leakage based on the measurement value within the target determination period, and the measurement value in the continuous period from the determination period that is a predetermined time before the target determination period to the target determination period , And a long-term determination D3 for determining the possibility of refrigerant leakage. According to the short-term determination D2, for example, when a large amount of refrigerant leaks within the target determination period, a sudden change appearing in the measured value can be detected to detect the refrigerant leakage. According to the long-term determination D3, for example, when the refrigerant leaks little by little before the target determination period, it is detected that the state where the measured value slightly deviates from the normal range continues for a long time, and refrigerant leakage is detected. it can. That is, when the short-term determination D2 and the long-term determination D3 are included, two types of refrigerant leaks with different types can be detected.

  In the short-term determination D2, it is erroneously determined that there is a possibility of refrigerant leakage, for example, when the product displayed on the cooling device 9 blocks the cold air inlet and the room temperature C0 temporarily rises. Can be considered. Therefore, when the long-term determination D3 is performed in addition to the short-term determination D2, there is a possibility that the short-term determination D2 is erroneously determined due to a temporary rise in the room temperature C0, etc. Can be excluded. Thus, if it is determined that there is a possibility of refrigerant leakage in both the short-term determination D2 and the long-term determination D3, it is possible to prevent erroneous detection of refrigerant leakage if it is determined that refrigerant leakage has occurred.

  It is possible to include a valve opening degree abnormality determination D1 for determining that there is a possibility of refrigerant leakage when a state where the valve opening degree OP is equal to or greater than a threshold value continues for a certain time or longer within the target determination period. . When the refrigerant amount decreases, the valve opening OP tends to be higher than that in the normal state in order to secure the refrigerant flow rate in the evaporator 14, and this tendency continues unless the refrigerant amount recovers. That is, when the state where the valve opening degree OP is high continues for a long time, it can be said that there is a high possibility that the refrigerant amount has decreased, that is, refrigerant leakage has occurred. Therefore, according to the valve opening degree abnormality determination D1, the presence or absence of refrigerant leakage can be determined with high accuracy. When the valve opening abnormality determination D1 is performed in addition to the short-term determination D2 and the long-term determination D3 and it is determined that there is a possibility of refrigerant leakage in all the determinations D1 to D3, It is possible to more reliably prevent erroneous detection of refrigerant leakage.

  When the valve opening degree abnormality determination D1 is performed with reference to the history of occurrence of a valve opening degree abnormality alarm that occurs when the valve opening degree OP is equal to or greater than a threshold value for a predetermined time or longer, a numerical value obtained by measuring the valve opening degree OP The determination is simpler than the case of referring to data, and the time required for the determination can be shortened. Further, when it is determined in the valve opening degree abnormality determination D1 that there is a possibility of refrigerant leakage, the short-term determination D2 and the long-term determination D3 are performed. If the possibility is denied, if the short-term determination D2 and the long-term determination D3 are not performed, the number of cases where the short-term determination D2 and the long-term determination D3 are performed can be reduced, and the time required for executing the refrigerant leak detection method can be shortened.

  The reference value used in the short-term determination D2 can be set based on the measured value in the reference period that is a predetermined time before the target determination period. At this time, if the reference period is close to the target determination period, the reference value may be set based on the measured value at the time of refrigerant leakage when refrigerant leakage has started in the reference period. Therefore, when the end point of the reference period is set in the vicinity of the start point of the continuous period in the long-term determination D3, a certain time interval is provided between the reference period and the target determination period, and there is a possibility that the refrigerant leakage starts in the reference period. Can be reduced. Thus, the short-term determination D2 and the long-term determination D3 can be accurately performed by setting the reference value to an appropriate value.

  In the freezer / refrigeration facility according to the present invention, the presence or absence of refrigerant leakage is determined based on the indoor temperature C0 of the cooling device 9, the superheat degree SH of the refrigerant at the outlet of the evaporator 14, and the valve opening OP of the expansion valve 15. The program for loading was installed in the terminal device 6 connected to the data server 5. That is, refrigerant leakage is detected based on the room temperature C0, the degree of superheat SH, and the valve opening degree OP. According to this, there is no need to provide a dedicated sensor for detecting refrigerant leakage as in the prior art, and the cost of the refrigeration equipment can be reduced accordingly. Furthermore, the freezing and refrigeration equipment according to the present invention can be applied to the existing freezing and refrigeration equipment with less effort without requiring a sensor installation work as in the prior art.

It is a conceptual diagram which shows the structure of a freezing apparatus. It is a whole block diagram of freezing and refrigeration equipment. It is a flowchart which shows the flow of a refrigerant | coolant leak detection method.

(Example) The Example of a refrigerant | coolant leak detection method and a refrigerant | coolant refrigeration installation provided with a refrigerant | coolant leak detection means based on this invention is described using FIGS. 1-3. FIG. 2 shows the overall configuration of the freezer / refrigeration facility, and a plurality of stores 1 and a remote monitoring center 2 are connected via the Internet 100. Each store 1 is provided with a plurality of refrigeration apparatuses 3 and a control panel 4 for monitoring and controlling the operation state of each refrigeration apparatus 3, and the operation data of each refrigeration apparatus 3 integrated in the control panel 4 is The data is periodically transmitted to the data server 5 installed in the remote monitoring center 2 via the Internet 100. The terminal device 6 connected to the data server 5 is equipped with a program for analyzing the operation data stored in the data server 5 and determining the presence or absence of refrigerant leakage.

  Each refrigeration apparatus 3 includes one refrigerator 8 and a plurality of cooling devices 9 connected to the refrigerator 8. Specific examples of the cooling device 9 include a refrigerator and a freezer in addition to the showcase 9A. FIG. 1 shows one refrigerator 8 and one showcase 9 </ b> A among a plurality of units connected to the refrigerator 8. The showcase 9A includes a display chamber 11 that is open on one side, a cool air circulation path 12 formed between a peripheral wall of the display chamber 11 and an outer peripheral wall of the showcase 9A, and a blower fan 13 disposed in the circulation path 12. And an evaporator 14, an electronic expansion valve 15, and the like. As the refrigerant evaporates in the evaporator 14, the cool air in the circulation path 12 is cooled, and the cooled cool air is blown out toward the display chamber 11. The refrigerator 8 includes a compressor 17, a condenser 18, a liquid receiver 19, and the like. The compressor 17, the condenser 18 and the liquid receiver 19, and the evaporator 14 and the expansion valve 15 of the showcase 9A are connected by a refrigerant pipe to constitute a refrigeration cycle.

  The showcase 9A includes an indoor temperature sensor 25 that measures the indoor temperature C0 of the display chamber 11, an inlet temperature sensor 26 that measures the refrigerant temperature on the inlet side of the evaporator 14, and the refrigerant temperature on the outlet side of the evaporator 14. An outlet temperature sensor 27 to be measured is provided, and the temperature measured by these temperature sensors 25 to 27 is transmitted to the control panel 4. The control panel 4 allows the indoor temperature C0 and the superheat degree SH of the refrigerant at the outlet of the evaporator 14 (a value obtained by subtracting the measured temperature of the inlet temperature sensor 26 from the measured temperature of the outlet temperature sensor 27) to be within the set range. In addition, the valve opening OP of the expansion valve 15 is controlled.

  The valve opening OP is controlled by the ratio of the opening time of the expansion valve 15 in the unit cycle time, and is set in increments of 1% between 0 and 100%. For example, when the unit cycle time is 10 seconds and the valve opening OP is set to 60%, the expansion valve 15 opens for 6 seconds and closes for 4 seconds in the unit cycle time. Further, the control panel 4 issues a valve opening failure alarm when the state where the valve opening OP is equal to or greater than the threshold value continues for a certain time or longer. In this embodiment, the threshold value of the valve opening OP is 90%, and the predetermined time is 10 minutes. That is, when the state of the valve opening OP ≧ 90% continues for 10 minutes or more, the control panel 4 issues a valve opening failure alarm. The control panel 4 also issues a valve opening failure alarm even when the state of the valve opening OP ≦ 10% continues for 1 minute or longer.

  The data server 5 stores operation data of the refrigeration apparatus 3 transmitted from the control panel 4 of each store 1, that is, operation data of the refrigerator 8 and the cooling device 9. Among these, the operation data of the cooling device 9 includes measured values of the room temperature C0, the superheat degree SH and the valve opening OP, and the occurrence history of the valve opening failure alarm, which are stored in the terminal device 6. By analyzing with a program, the presence or absence of refrigerant leakage in the refrigeration cycle of the cooling device 9 can be determined.

  The refrigerant leak detection method according to the present embodiment sets a determination period having a predetermined time width, and determines whether or not there is a refrigerant leak for each determination period. In the example, it was 1 day (24 hours). That is, in this embodiment, for each refrigeration cycle of the cooling device 9, a determination result such as ◯ month Δ day: no refrigerant leakage, ◯ month □ day: refrigerant leakage,. In the following, a determination period that is a target for determining whether there is a refrigerant leak, that is, a target determination period is referred to as a target day.

  In this embodiment, as shown in the flowchart of FIG. 3, the valve opening abnormality determination D1, the short-term determination D2, and the long-term determination D3 are sequentially performed. Details of the determinations D1 to D3 will be described later. If three determinations D1 to D3 are performed and it is determined that there is a possibility of refrigerant leakage in all of them, it is determined that refrigerant leakage has occurred on the target day. Conversely, if it is determined in any of the three determinations D1 to D3 that there is no possibility of refrigerant leakage, it is determined that no refrigerant leakage has occurred on the target day.

  Below, each said determination D1-D3 is demonstrated in order. In the valve opening abnormality determination D1 that is performed first, the occurrence history of the valve opening failure alarm on the target day is referred to (step S1). Here, if an alarm is generated on the target day (YES in step S1), it is determined that there is a possibility of refrigerant leakage, and the process proceeds to the next short-term determination D2. On the other hand, if the alarm has not occurred (NO in step S1), it is determined that there is no possibility of refrigerant leakage, and it is determined that no refrigerant leakage has occurred on the target day. The analysis is terminated without performing D3.

In the short-term determination D2, first, the following values [1] to [4] are calculated from the measured values of the room temperature C0, the superheat degree SH, and the valve opening degree OP on the target day (step S2). The threshold value of [1] was 90%, and the threshold value of [4] was (set value of room temperature C0 + 2) ° C.
[1] Number of measured values of the valve opening OP that are equal to or greater than the threshold value [2] Sum of measured values of the valve opening OP [3] Sum of measured values of the superheat degree SH [4] Measured value of the indoor temperature C0 The number of those above the threshold

  In each day (each judgment period), the room temperature C0 and the like are measured at arbitrary time intervals. This time interval is set to about several minutes to several tens of minutes. If this time is, for example, 6 minutes, the number of times of measurement per day is 240 times. In step S2, the values [1] to [4] are calculated based on the measured values such as the room temperature C0 measured multiple times on the target day. Note that the time interval for measuring the room temperature C0 and the like, that is, the number of times of measurement, need not be the same for all of the room temperature C0, the degree of superheat SH, and the valve opening degree OP.

  Next, a reference value is set for each of [1] to [4] (step S3). The reference value may be a fixed value set in advance, but in this embodiment, the reference value is set based on a measured value such as the room temperature C0 in a reference period that is a predetermined time before the target date. Specifically, 10 days 24 to 15 days before the target date are used as the reference period, and the values [1] to [4] are calculated for each day (each judgment period) of the reference period, and the average value is used as the reference value. Value. In addition, when the frequency | count of measurement of the indoor temperature C0 etc. in each day of a reference | standard period differs from the frequency | count of measurement on a target day, adjustment according to the frequency | count of measurement on a target day is performed. For example, when the number of times of measurement on the target day is twice that of each day of the reference period, the average value of values obtained by doubling [1] to [4] of each day of the reference period is used as the reference value. Use.

  Next, the value of the ratio of each value of [1] to [4] on the target date to the reference value is calculated as a change rate (step S4). For example, the rate of change of [1] is obtained by dividing the value of [1] on the target date by the reference value of [1]. Finally, the rate of change [1] to [4] is compared with a threshold value (step S5). If three or more of the change rates [1] to [4] exceed the threshold (YES in step S5), it is determined that there is a possibility of refrigerant leakage, and the process proceeds to the next long-term determination D3. On the other hand, when the number exceeding the threshold is two or less (NO in step S5), it is determined that there is no possibility of refrigerant leakage, it is determined that no refrigerant leakage has occurred on the target day, and the long-term determination D3 is set. End the analysis without doing it. In this example, the threshold value was set to 1.2 (120%) for each of the change rates of [1] to [4].

  In the long-term determination D3, a continuous period from a date (determination period) before the target date (target determination period) to the target day by a predetermined time is set. In this example, the continuous period was 16 days from 15 days before the target day to the target day. In this embodiment, the day that is the start point of the continuous period coincides with the day that is the end point of the reference period in the previous step S3 (both 15 days before the target day).

  The change rates of [1] to [4] on each day (each judgment period) of the continuous period are summed to calculate the change rate integral of [1] to [4] (step S6), and then [1 ] To [4] are compared with a threshold value (step S7). If there are two or more change rate integrals of [1] to [4] that exceed the threshold (YES in step S7), it is determined that there is a possibility of refrigerant leakage. Thus, when it is determined that there is a possibility of refrigerant leakage in all three determinations D1 to D3, it is determined that refrigerant leakage has occurred on the target day. On the other hand, when the number exceeding the threshold is 1 or less (NO in step S7), it is determined that there is no possibility of refrigerant leakage, it is determined that no refrigerant leakage has occurred on the target day, and the analysis is terminated. . In this embodiment, the threshold value is set to 17 for each of the change rate integrals [1] to [4]. When this threshold is divided by the number of days in the continuous period, 17 ÷ 16 = 1.0625 (106.25%). This value is smaller than the threshold value 1.2 (120%) regarding the change rate in the previous step S5.

  In order to confirm that the refrigerant leak detection method according to the present example is effective, verification was performed using past operation data. The operation data of a total of 10019 cooling devices 9 installed in 133 stores were subjected to verification, and the verification period was 280 days. That is, the number of cases where the presence or absence of refrigerant leakage is determined is 1,0019 units × 280 days = 2805320 cases. Of the 1,0019 cooling devices 9, three were actually repaired for refrigerant leakage during the verification period, two of which were repaired once, and the other one was repaired three times. It had been.

  Of the 2805320 cases, it was determined that there was a possibility of refrigerant leakage in all three of the valve opening abnormality determination D1, the short-term determination D2, and the long-term determination D3, and 37 cases were finally determined to have refrigerant leakage. Met. Of these 37 cases, 36 were from the past repair date of the three cooling devices 9 that were actually repaired. From the above verification results, it was confirmed that the refrigerant leak detection method according to the present example can reliably detect the refrigerant leak. Further, out of 37 cases judged to have a refrigerant leak, the number of erroneous detections was only one, and it was confirmed that the refrigerant leak detection method according to the present example was highly accurate.

  As another embodiment of the present invention, the change rate of [1] to [4] exceeding the threshold in step S5 of the above embodiment is changed to “2 or more” where “3 or more” is exceeded. did. That is, the conditions for determining that there is a possibility of refrigerant leakage were relaxed, and the same verification was performed. In this verification, all three of the valve opening degree abnormality determination D1, the short-term determination D2, and the long-term determination D3 are determined to have the possibility of refrigerant leakage, and finally, 2805320 cases were determined to have refrigerant leakage. Of these, there were 133 cases, a significant increase from the previous example (37 cases). Of these 133 cases, 83 were those in the near future of the repair date in the three cooling devices 9 that were actually repaired.

  If the conditions are relaxed as compared with the previous example, the number of cases in which refrigerant leakage can be correctly detected increases (36 cases → 83 cases), and refrigerant leakage can be detected earlier, Correspondingly, the number of false positives increases (1 case → 50 cases). That is, if priority is given to early detection of refrigerant leakage, the conditions of the determinations D1 to D3 may be relaxed, and if priority is given to increasing accuracy by reducing false detections, the determinations of the determinations D1 to D3. You can tighten the conditions.

In addition, the following have been confirmed as factors of erroneous detection of refrigerant leakage.
・ Problem of display method The cold air intake port of the cooling device 9 was blocked by the display product, and the cold air in the display room 11 leaked outside, causing an abnormality such as the room temperature C0 rising.
Change in setting of the room temperature C0 As a result of setting the set value of the room temperature C0 to a low temperature, in order to maintain the room temperature C0 of the display room 11 at a low temperature, a state where the refrigerant flowing through the evaporator 14 increases, that is, The state where the valve opening OP was high continued.
-Failure of expansion valve 15 The expansion valve 15 did not operate as instructed by the control panel 4, and an abnormality such as an increase in superheat degree SH due to insufficient refrigerant flowing through the evaporator 14 occurred.
・ Insufficient amount of refrigerant enclosed If the amount of refrigerant enclosed is insufficient from the beginning, the valve is opened to secure the refrigerant flow rate in the evaporator 14, especially in winter when the outside air temperature is low and the refrigerant volume is small. A state with a high degree of OP continues.

  In the above embodiment, when it is determined that there is a possibility of refrigerant leakage in all three of the valve opening abnormality determination D1, the short-term determination D2, and the long-term determination D3, it is determined that the refrigerant leakage has occurred. However, the present invention is not limited to this. For example, when it is determined in the valve opening degree abnormality determination D1 that there is a possibility of refrigerant leakage, and it is determined that there is a possibility of refrigerant leakage in at least one of the short-term determination D2 and the long-term determination D3, refrigerant leakage occurs. Can be determined. According to this, since it is possible to detect that a large amount of refrigerant leaks on the target day by the short-term determination D2, and it is possible to detect that the refrigerant leaks little by little from before the target day, it is possible to detect the type of Two different types of refrigerant leakage can be detected at an early stage.

  Instead of calculating the sum of the valve opening degree OP and the superheat degree SH in step S2 of the short-term determination D2, it can be changed to calculate an average. In step S5 of the short-term determination D2 and step S7 of the long-term determination D3, the number of the change rate or change rate integration is determined as to whether or not it is determined that there is a possibility of refrigerant leakage (YES). The order in which the determinations D1 to D3 are performed and the threshold values in the determinations D1 to D3 are not limited to those in the above-described example, and the length of the determination period for determining the presence or absence of refrigerant leakage is also one day ( 24 hours). In addition to the indoor temperature C0, the superheat degree SH, and the valve opening degree OP, the presence or absence of refrigerant leakage may be determined based on another measured value.

  In the above embodiment, the valve opening abnormality alarm is generated in the control panel 4, but it may be generated in the cooling device 9, or may be generated in both. Instead of connecting a plurality of cooling devices 9 to a single refrigerator 8, the refrigerator 8 and the cooling devices 9 may be connected on a one-to-one basis. The compressor 17, the condenser 18 and the liquid receiver 19 may be installed in the cooling device 9. By installing the data server 5 and the terminal device 6 in the store 1, the refrigerant leak detection method of the present invention can be carried out in the store 1.

3 Refrigeration apparatus 4 Control panel 8 Refrigerator 9 Cooling device 11 Display chamber 14 Evaporator 15 Expansion valve 17 Compressor 18 Condenser 25 Indoor temperature sensor 26 Inlet temperature sensor 27 Outlet temperature sensor C0 Indoor temperature SH Superheat degree OP Valve opening

Claims (10)

Compressor (17), the indoor condenser (18), in a refrigeration cycle having an expansion valve (15) and an evaporator (14), the cooling device is cooled by evaporation of the refrigerant in the vapor Hatsuki (14) (9) A refrigerant leak detection method for determining the presence or absence of a refrigerant leak based on the temperature (C0), the degree of superheat (SH) of the refrigerant at the outlet of the evaporator (14), and the valve opening (OP) of the expansion valve (15). There,
A determination period having a predetermined time width is set, and the presence or absence of refrigerant leakage is determined for each determination period.
Target determination based on each value of the indoor temperature (C0), the degree of superheat (SH), and the valve opening (OP) measured during the determination period for determining whether or not there is refrigerant leakage, that is, the target determination period Short-term determination (D2) for determining the possibility of refrigerant leakage in the period;
Based on the measured values of the indoor temperature (C0), the degree of superheat (SH), and the valve opening (OP) in the continuous period from the determination period that is a predetermined time before the target determination period to the target determination period, the target determination period And a long-term determination (D3) for determining the possibility of refrigerant leakage in the refrigerant . The refrigerant leak detection according to claim 1, wherein when it is determined that there is a possibility of refrigerant leakage in both the short-term determination (D2) and the long-term determination (D3), it is determined that the refrigerant leak has occurred in the target determination period. Method. Valve opening abnormality determination (D1) for determining that there is a possibility of refrigerant leakage in the target determination period when a state where the valve opening (OP) is equal to or greater than the threshold value continues for a certain time or longer within the target determination period Including
When it is determined that there is a possibility of refrigerant leakage in all of the valve opening abnormality determination (D1), the short-term determination (D2), and the long-term determination (D3), it is determined that a refrigerant leak has occurred during the target determination period. The refrigerant leak detection method according to claim 2. In the cooling device (9) or the control panel (4) for monitoring the cooling device (9), a valve opening abnormality alarm is generated when a state where the valve opening (OP) is equal to or greater than a threshold value continues for a predetermined time or longer. And
When the valve opening abnormality determination (D1) is performed with reference to the occurrence history of the valve opening abnormality alarm within the target determination period, and it is determined that there is a possibility of refrigerant leakage in the valve opening abnormality determination (D1). The refrigerant leak detection method according to claim 3 , wherein short-term determination (D2) and long-term determination (D3) are performed . Short-term judgment (D2) was measured at an arbitrary interval within the target judgment period
[1] The number of measured values of valve opening (OP) that are above the threshold
[2] Sum or average of measured values of valve opening (OP)
[3] Sum or average of measured values of superheat (SH)
[4] Number of measured values of room temperature (C0) that are equal to or greater than a threshold value
(S2) for calculating each, step (S3) for setting a reference value for each of [1] to [4], and the ratio of each value of [1] to [4] to the reference value in the target determination period The step (S4) of calculating the value of the above as a rate of change, and the step (S5) of comparing each rate of change of [1] to [4] with a threshold value,
The long-term determination (D3) includes a step (S6) of calculating the change rate integral by summing up the change rates of [1] to [4] in each determination period constituting the continuous period, and [1] to [4]. Step (S7) of comparing each change rate integral of
The reference value in the short-term determination (D2) is set based on the measured values of the room temperature (C0), the degree of superheat (SH), and the valve opening (OP) in the reference period that is a predetermined time before the target determination period. And
The refrigerant leak detection method according to any one of claims 1 to 4, wherein an end point of the reference period is set in the vicinity of a start point of a continuous period in the long-term determination (D3) . A refrigeration cycle having a compressor (17), a condenser (18), an expansion valve (15) and an evaporator (14); a cooling device (9) cooled by evaporation of refrigerant in the evaporator (14); A refrigerant refrigeration facility comprising a cycle refrigerant leakage detection means,
The refrigerant leakage detection means includes a control panel (4) that monitors and controls the operating state of the cooling device (9), and a data server (5) that exchanges operating data of the cooling device (9) integrated in the control panel (4). ) And a terminal device (6) connected to the data server (5),
Based on the indoor temperature (C0) of the cooling device (9), the superheat degree (SH) of the refrigerant at the outlet of the evaporator (14), and the valve opening (OP) of the expansion valve (15) included in the operation data. , A program for judging the presence or absence of refrigerant leakage is installed in the terminal device (6),
The program of the terminal device (6) is
A determination period having a predetermined time width is set, and the presence or absence of refrigerant leakage is determined for each determination period.
Target determination based on each value of the indoor temperature (C0), the degree of superheat (SH), and the valve opening (OP) measured during the determination period for determining whether or not there is refrigerant leakage, that is, the target determination period Short-term determination (D2) for determining the possibility of refrigerant leakage in the period;
Based on the measured values of the indoor temperature (C0), the degree of superheat (SH), and the valve opening (OP) in the continuous period from the determination period that is a predetermined time before the target determination period to the target determination period, the target determination period A long-term determination (D3) for determining the possibility of refrigerant leakage in the refrigerator. The program of the terminal device (6) is
The refrigerating / refrigeration equipment according to claim 6, wherein when it is determined that there is a possibility of refrigerant leakage in both the short-term determination (D2) and the long-term determination (D3), it is determined that a refrigerant leak has occurred in the target determination period. . The program of the terminal device (6) is
Valve opening abnormality determination (D1) for determining that there is a possibility of refrigerant leakage in the target determination period when a state where the valve opening (OP) is equal to or greater than the threshold value continues for a certain time or longer within the target determination period Including
When it is determined that there is a possibility of refrigerant leakage in all of the valve opening abnormality determination (D1), the short-term determination (D2), and the long-term determination (D3), it is determined that a refrigerant leak has occurred during the target determination period. The refrigeration equipment of Claim 7. In the control panel (4), when the valve opening (OP) is equal to or greater than the threshold value for a certain time or longer, a valve opening abnormality alarm is generated.
The program of the terminal device (6) is
When the valve opening abnormality determination (D1) is performed with reference to the occurrence history of the valve opening abnormality alarm within the target determination period, and it is determined that there is a possibility of refrigerant leakage in the valve opening abnormality determination (D1). The freezer / refrigeration equipment according to claim 8 , wherein short-term determination (D2) and long-term determination (D3) are performed . Short-term judgment (D2) was measured at an arbitrary interval within the target judgment period
[1] The number of measured values of valve opening (OP) that are above the threshold
[2] Sum or average of measured values of valve opening (OP)
[3] Sum or average of measured values of superheat (SH)
[4] Number of measured values of room temperature (C0) that are equal to or greater than a threshold value
(S2) for calculating each, step (S3) for setting a reference value for each of [1] to [4], and the ratio of each value of [1] to [4] to the reference value in the target determination period The step (S4) of calculating the value of the above as a rate of change, and the step (S5) of comparing each rate of change of [1] to [4] with a threshold value,
The long-term determination (D3) includes a step (S6) of calculating the change rate integral by summing up the change rates of [1] to [4] in each determination period constituting the continuous period, and [1] to [4]. Step (S7) of comparing each change rate integral of
The reference value in the short-term determination (D2) is set based on the measured values of the room temperature (C0), the degree of superheat (SH), and the valve opening (OP) in the reference period that is a predetermined time before the target determination period. And
The refrigeration equipment according to any one of claims 6 to 9, wherein an end point of the reference period is set in the vicinity of a start point of a continuous period in the long-term determination (D3) .

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