Refrigeration device and showcase equipped with refrigeration device

Abstract

To provide a refrigeration device and a showcase provided with the same capable of securing safety against a leakage of a coolant even when power source voltage fluctuates.SOLUTION: A refrigeration device comprises: a body where a compressor, a condenser, a reducer, and an evaporator are connected through piping and a coolant circuit distributing a coolant is arranged therein; a condenser blower which is arranged in a machine room compartmentalized so as to arrange the condenser inside the body; and a control device which controls an operational electric current value of the condenser blower so that operation of the condenser blower can maintain set air volume, minimum air volume necessary for maintaining a concentration of a coolant in the machine room equal to or less than a lean flammable limit. The control device detects that the air volume of the condenser blower becomes lower than the set air volume on the basis of an actual electric power value and an abnormality determination value corresponding to the set air volume.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a refrigeration device and a showcase equipped with a refrigeration device, and more particularly to detection of an abnormality in a decrease in airflow in a refrigeration device and a showcase equipped with a refrigeration device. [Background technology]

[0002] Stores such as supermarkets and convenience stores are equipped with showcases used for refrigeration or freezing. The showcase is equipped with a refrigeration device having a refrigerant circuit in which a compressor, a condenser, a throttling device, and an evaporator are connected by piping, and a refrigerant circulates. The showcase is designed to cool a storage compartment in the showcase by evaporating the refrigerant in the evaporator of the refrigerant circuit. One of the causes of the deterioration of cooling performance, which is a defect, is that the condenser becomes clogged with dirt and the like due to deterioration over time, which reduces the heat exchanger performance.

[0003] On the other hand, refrigerants used in showcases and the like include R404A and R410A, but they have high GWP (global warming potential) of 3920 and 2090, respectively, and there is a demand for lower GWP. In recent years, in response to the need for lower GWP, an increasing number of showcases use R290 (propane, GWP 3.3) or R600a (isobutane, GWP 4), which have similar efficiency to R404A or R410A.

[0004] R290 or R600a is a flammable refrigerant. The Japan Refrigeration and Air Conditioning Industry Association standard JRA4078:2021 describes what is required in the event of a flammable refrigerant leak. Specifically, it is described that the air volume of the blower is constantly monitored and maintained at the limit air volume calculated by a predetermined formula so that the leaked flammable refrigerant can be stirred by the condenser blower, and that an alarm is issued if the limit air volume cannot be maintained. It is also described that the air volume of the condenser blower may be estimated by means of, for example, wind speed, blower rotation speed, or current.

[0005] Therefore, in showcases, it is necessary to accurately detect a decrease in air volume in order to identify clogging of the condenser, which affects the deterioration of cooling performance, and to ensure sufficient air volume for the condenser fan in response to leaks of flammable refrigerants, the use of which is increasing in response to low GWP.

[0006] Here, the method of detecting a decrease in air volume is the method using the wind speed, the fan rotation speed, or the current described in JRA4078:2021. The wind speed of the fan can be measured using an anemometer such as a vane type, a hot wire type, or an ultrasonic type, but there are no compact and low-cost anemometers, and in a dense structure such as the condenser part of a refrigeration device, it is not possible to identify a position where the wind speed can be accurately measured.

[0007] Meanwhile, for example, Patent Document 1 describes a method of operating a DC brushless fan that does not have a brush structure and does not have a contact structure inside so that the rotation speed of the fan reaches a target rotation speed. A DC brushless fan is effective because the current value increases when the speed adjustment voltage is increased so that the rotation speed reaches the target rotation speed, and the fan current can be measured by a small servo-type current sensor. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2021 / 111624 Summary of the Invention [Problem to be solved by the invention]

[0009] In Patent Document 1, the speed control voltage is increased so that the rotation speed of the DC brushless blower reaches a target rotation speed, so that a decrease in the rotation speed of the blower due to clogging of the condenser is unlikely to occur.

[0010] In addition, for 100V models of showcases on the market, the power supply voltage fluctuates between 90V and 110V, and this difference causes the current value to deviate, which may lead to false alarms in methods that measure the current of the blower to detect a drop in air volume.As a result, if a flammable refrigerant is used in the refrigeration device of the showcase to comply with low GWP, safety against refrigerant leakage cannot be ensured depending on the power supply voltage situation or voltage value fluctuations in the store where the showcase is installed.

[0011] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a refrigeration device and a showcase equipped with a refrigeration device that can ensure safety against refrigerant leakage even if the power supply voltage fluctuates. [Means for solving the problem]

[0012] The refrigeration device according to the present disclosure includes a main body in which a refrigerant circuit is arranged, in which a compressor, a condenser, a throttling device, and an evaporator are connected by piping, and in which a refrigerant flows; a condenser blower arranged in a machine room partitioned so that the condenser is arranged within the main body; and a control device that controls an operating current value of the condenser blower so that a set air volume, which is a minimum air volume necessary to keep the concentration of the refrigerant below the lower flammability limit, is maintained within the machine room by operating the condenser blower, and the control device detects that the air volume of the condenser blower has fallen below the set air volume, based on an actual operating power value and an abnormality determination value corresponding to the set air volume. The control device further determines whether the compressor is operating or not, and changes the abnormality determination value depending on whether the compressor is operating or not. It is something. Further, a refrigeration device according to the present disclosure includes a main body in which a refrigerant circuit is arranged, in which a compressor, a condenser, a throttling device, and an evaporator are connected by piping, and in which a refrigerant flows; a condenser blower arranged in a machine room partitioned so that the condenser is arranged in the main body; and a control device that controls an operating current value of the condenser blower so that a set air volume, which is a minimum air volume necessary to keep the concentration of the refrigerant at or below the lower flammability limit, is maintained in the machine room by operating the condenser blower, and the control device controls an actual operating power value and a current value corresponding to the set air volume. an abnormality determination value and an initial operating power value of the condenser blower, the initial operating power value being obtained by integrating an initial operating current value of the condenser blower that is measured in advance and an initial drive voltage value of the condenser blower that corresponds to the initial operating current value, and the initial operating power value is obtained from the initial operating current value and drive voltage value measured at a time other than when the compressor is started or stopped. Effect of the Invention

[0013] According to the refrigeration device of the present disclosure, an abnormality caused by a decrease in the amount of air flowing to the condenser is detected and left unattended based on the power value of the condenser blower, so that safety against refrigerant leakage in the refrigeration device can be ensured even if there are fluctuations in the power supply voltage in the store in which the refrigeration device is installed. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing a showcase according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a drain water evaporator of the showcase according to the embodiment. [Diagram 3] 5 is a diagram showing a positional relationship between a condenser and a condenser blower of the showcase according to the embodiment. FIG. [Figure 4] FIG. 2 is a schematic diagram showing a current sensor of the showcase according to the embodiment. [Diagram 5] FIG. 2 is a diagram showing a control device for a showcase according to an embodiment. [Figure 6] 4 is a diagram showing a control board incorporated in a condenser blower of the showcase according to the embodiment and a main board of a control device. FIG. [Figure 7] 11 is a diagram showing the relationship between the rotation speed of a condenser blower, a speed control voltage, and an operating current value in the showcase according to the embodiment. FIG. [Figure 8] 11 is a diagram showing a relationship between a power supply voltage and an operating current value of a condenser blower of the showcase according to the embodiment. FIG. [Figure 9] 13 is a flowchart for determining an abnormality determination value used for detecting an abnormality in the air volume decrease of the condenser blower 6 during assembly of the showcase according to the embodiment. [Figure 10] 13 is a flowchart for detecting an abnormality in the decrease in air volume of a condenser blower 6 during actual operation of the showcase according to the embodiment. [Figure 11] FIG. 13 is a schematic diagram showing a first modified example of the showcase according to the embodiment. [Figure 12] FIG. 11 is a diagram showing a positional relationship between an evaporator and an in-compartment blower of a showcase according to a second modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a refrigeration device and a showcase equipped with a refrigeration device according to an embodiment will be described with reference to the drawings. In the following drawings, the relative dimensional relationship and shape of each component may differ from the actual one. In the following drawings, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification. In addition, the alphabet after the numerals in the reference numerals in the drawings may be omitted in the explanation. In addition, terms indicating directions, such as "up", "down", "right", "left", "front" or "rear", are used as appropriate to facilitate understanding. However, the terms indicating directions are described for the convenience of explanation and do not limit the arrangement and orientation of the device or parts.

[0016] Embodiment <Showcase Configuration> Fig. 1 is a schematic diagram showing a showcase 1 according to an embodiment. The showcase 1 of the embodiment is a showcase 1 with a built-in refrigeration device. As shown in Fig. 1, the showcase 1 is a vertical open showcase.

[0017] The main body 1a of the showcase 1 has an insulating wall 8 with an opening at the front 1b, and side panels (not shown) attached to both sides of the insulating wall 8. An inner layer partition plate 9 is attached at an interval to the inside of the insulating wall 8, and an inner layer duct 10 is formed between the insulating wall 8 and the inner layer partition plate 9. The inside of the inner layer partition plate 9 is a storage chamber 11 which is the interior of the cabinet. The insulating wall 8 and the inner layer partition plate 9 are also referred to as a housing.

[0018] In the storage room 11, there are provided a plurality of shelves 12 for displaying products, for example, four shelves. The first shelf, which is the topmost shelf, is designated AA, the second shelf is designated BB, the third shelf is designated CC, and the fourth shelf is designated DD. Fluorescent lamps 13 for illumination are attached to the front lower surface of each shelf 12 and to the ceiling 10a of the storage room 11. A bottom duct 14 communicating with the inner layer duct 10 is provided below the bottom of the storage room 11. An internal fan 15 is installed in the bottom duct 14. An evaporator 5 is vertically installed in the lower part of the inner layer duct 10 located on the rear surface 1c side of the storage room 11.

[0019] An air outlet 17 is formed at the upper edge of the front opening 16 of the storage chamber 11. An air inlet 18 is formed at the lower edge of the front opening 16. The lower part of a bottom partition plate 19 forming the bottom surface of the bottom duct 14 serves as a machine chamber 20.

[0020] The bottom partition plate 19 is provided with a drain pan 21 for receiving drain water such as defrost water generated from the evaporator 5 disposed above the bottom partition plate 19. The drain pan 21 is formed with a drain outlet 21a for allowing the drain water to fall toward a drain water evaporator 22 in the machine room 20.

[0021] <Configuration of drain water evaporation device> Fig. 2 is a schematic diagram showing a drain water evaporator 22 of a showcase 1 according to an embodiment. As shown in Fig. 2, the drain water evaporator 22 includes an evaporation dish 23 for storing drain water, a plurality of evaporation plates 24, and a plurality of support members 27 for integrally supporting the plurality of evaporation plates 24. In Fig. 2, the arrow indicates the wind passing direction. The plurality of evaporation plates 24 are arranged so as to be parallel to the wind passing direction. The plurality of evaporation plates 24 are arranged on the evaporation dish 23. The evaporation plate 24 is made of, for example, a nonwoven fabric in which PET (polyethylene terephthalate) and glass fiber are integrated, or a porous resin molded body.

[0022] Returning to Fig. 1, the machine room 20 accommodates a compressor 2, a condenser 3, a throttling device 4, a condenser blower 6 (see Fig. 3 described later), and a control device 7. The machine room 20 also accommodates a high pressure switch 30.

[0023] The compressor 2 draws in low-temperature and low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature and high-pressure refrigerant. The compressor 2 is, for example, an inverter compressor whose capacity, which is the amount of refrigerant discharged per unit time, is controlled by changing the operating frequency. The condenser 3 exchanges heat between the air and the refrigerant, condensing and liquefying the refrigerant. The throttling device 4 reduces the pressure of the refrigerant and expands it. The throttling device 4 is, for example, an electronic expansion valve that can adjust the opening degree of the throttling.

[0024] The control device 7 controls the entire showcase 1. The operating current value of the condenser blower 6 measured by the current sensor 28 (see FIG. 3) is input to the control device 7. The control device 7 detects an abnormality in the decrease in air volume of the condenser blower 6 caused by clogging of the condenser 3 based on a power value which is the product of the operating current value measured by the current sensor 28 and the drive voltage of the condenser blower 6. When the control device 7 detects that the air volume of the condenser blower 6 has fallen below a preset air volume, it outputs an alarm notifying the abnormality in the decrease in air volume. The alarm may be issued in any form such as a sound or a display. The alarm may be output by, for example, a buzzer or a message. The detection of an abnormality in the decrease in air volume of the condenser blower 6 will be described later.

[0025] The high pressure switch 30 is connected to the discharge side of the compressor 2 and stops the compressor 2 as a protective action when the pressure discharged from the compressor 2, i.e., the high pressure, exceeds a set value.

[0026] 1, an operation panel 26 for user operation is attached to the outside of the eaves 25 provided on the upper part of the heat insulating wall 8. On the operation panel 26, operation input for setting the temperature and the like is performed.

[0027] <Positional Relationship Between the Condenser 3 and the Condenser Blower 6> Fig. 3 is a diagram showing the positional relationship between the condenser 3 and the condenser blower 6 of the showcase 1 according to the embodiment. Fig. 4 is a schematic diagram showing a current sensor 28 of the showcase 1 according to the embodiment.

[0028] As shown in Fig. 3 and Fig. 4, the condenser blower 6 blows air to cool the condenser 3, and the wiring 6a of the wirings 6a-6e (see Fig. 6 described later) of the condenser blower 6 passes through a current sensor 28 and is connected to the control device 7. The condenser blower 6 draws air into the machine room 20 from the left side surface 1e of the showcase 1 and discharges it to the outside from the right side surface 1d. In the machine room 20, partition plates 33a and 33b are arranged to separate the machine room 20 into the left side surface 1e side and the right side surface 1d side with the condenser 3 as a boundary. This ensures that the air taken into the machine room 20 passes through the condenser 3.

[0029] The condenser 3 is connected to a discharge pipe 34 of the compressor 2, and the refrigerant discharged from the compressor 2 flows into the condenser 3. An operating current value, which is a current value during operation of the condenser blower 6, is measured by a current sensor 28, and output to the control device 7. The current sensor 28 converts a magnetic field generated around the measured current into a voltage by utilizing the Hall effect, for example, and the converted voltage is output as an output voltage.

[0030] <Control device 7> Fig. 5 is a diagram showing the control device 7 of the showcase 1 according to the embodiment. As shown in Fig. 5, the control device 7 is configured with, for example, a main board 7a and a memory 7b. Note that the configuration of the control device 7 is not limited to this. For example, the control device 7 may use a microprocessor unit or the like as the main board 7a, and may be configured with updatable firmware or the like.

[0031] The memory 7b is a storage unit that stores various data necessary for operation control of the showcase 1. The memory 7b is composed of a non-volatile rewritable memory such as an E2ROM (Electrucally Erasable ROM) or an E2PROM (Electrucally Erasable Programmable ROM). The memory 7b may be composed of a volatile memory in addition to a non-volatile memory.

[0032] The compressor 2, condenser 3, throttling device 4, and evaporator 5 are connected in sequence by piping to form a refrigerant circuit 40 (see FIG. 1) in which the refrigerant circulates through the piping. The refrigerant discharged from the compressor 2 is cooled by the condenser 3 by dissipating heat into the outside air blown by the condenser blower 6, and is depressurized by the throttling device 4. The refrigerant depressurized by the throttling device 4 evaporates in the evaporator 5 and returns to the compressor 2. The above completes the refrigeration cycle of the showcase 1.

[0033] <Working fluid in showcase 1> In the showcase 1, a flammable refrigerant that is an HC refrigerant with a global warming potential of 1500 or less, such as propane or isobutane, is used as the refrigerant that is the working fluid. Propane has a global warming potential of 3.3, and isobutane has a global warming potential of 4. In this technical field, the global warming potential is also abbreviated as GWP. In addition to the flammable refrigerant, a slightly flammable refrigerant such as R32 or an HFO refrigerant may be used as the refrigerant.

[0034] The showcase 1 is an integrated device including a refrigeration unit, and therefore can be made compact. By making it compact, for example, in the case of propane, which has a low liquid density, the amount of refrigerant to be filled can be reduced to about 500 g. The International Electrotechnical Commission (IEC) has relaxed regulations on the upper limit of flammable refrigerants that can be filled into household and commercial refrigeration equipment, increasing the filling amount from 150 g to 500 g. Because the showcase 1 is an integrated device including a refrigeration unit, it is possible to provide a showcase 1 that meets safety standards against refrigerant leakage, even when a flammable refrigerant with a global warming potential of 1500 or less, such as propane, is used.

[0035] <Showcase 1 Operation> When the interior blower 15 is operated, the air in the bottom duct 14 is blown out toward the rear inner duct 10. After exchanging heat with the evaporator 5, the air is blown up and is blown out from the air outlet 17 at the upper edge of the front opening 16 toward the air inlet 18 at the lower edge.

[0036] As a result, a cold air curtain is formed at the front opening 16 of the storage room 11. The cold air curtain prevents or suppresses the intrusion of outside air into the storage room 11 from the front opening 16. Also, some of the cold air forming the cold air curtain circulates inside the storage room 11, thereby cooling the inside of the storage room 11. When the store in which the showcase 1 is installed is closed, a night cover 31 is placed on the showcase 1 to close the front opening 16.

[0037] The air blown out from the air outlet 17 forms a cold air curtain or cools the storage compartment 11, and then returns to the bottom duct 14 from the air inlet 18 and is sucked again by the interior blower 15.

[0038] During operation of the showcase 1, drain water such as defrost water generated in the evaporator 5 falls into the drain pan 21, falls from the drain outlet 21a onto the evaporation plate 24 of the drain water evaporation device 22, and accumulates in the evaporation tray 23. The drain water accumulated in the evaporation tray 23 is sucked up by the evaporation tray 24 due to capillary action. The configuration for impregnating the evaporation plate 24 with drain water may further include a configuration in which the drain water accumulated in the evaporation tray 23 is sucked up by a pump or the like and sprayed from above the evaporation plate 24.

[0039] Then, the wind from the condenser blower 6 passes through the condenser 3 and is heated, and then is blown toward the drain water evaporator 22. The warm wind blown toward the drain water evaporator 22 is blown against the evaporator plate 24 of the drain water evaporator 22, thereby evaporating the drain water contained in the evaporator plate 24.

[0040] When the temperature inside the showcase 1 is about 10°C or less during operation, the water adhering to the evaporator 5 frosts on the evaporator 5. As the frost advances, the amount of heat exchange in the evaporator 5 decreases, and the evaporation performance decreases. For this reason, the showcase 1 detects the degree of frost and, when it determines that the evaporator 5 needs to be defrosted, performs defrosting of the evaporator 5. As a method for detecting the degree of frost, for example, a configuration can be adopted in which it is performed based on the operating time of the compressor 2, and when the operating time reaches a predetermined time, it is determined that the evaporator 5 needs to be defrosted. Defrosting is performed by energizing a heater (not shown) arranged on the evaporator 5 for a predetermined time. When defrosting is performed, the drain water falls into the drain pan 21 as described above, and then falls from the drain outlet 21a onto the evaporation plate 24 of the drain water evaporation device 22, and accumulates in the evaporation dish 23. The evaporation dish 23 may be provided with a float switch (not shown) for detecting the amount of drain water drained.

[0041] <Measures against refrigerant leakage> It is assumed that a refrigerant leak occurs from the discharge pipe 34 of the compressor 2 in the machine room 20 of the showcase 1. The amount of refrigerant filled in the refrigeration device in this case is 500 g, which is the allowable filling amount of flammable refrigerant revised in ISC60335-2-89:2019. In addition, the leak rate is 7.5 kg / h, which is the 4-minute total leak rate under the condition that the entire amount of the filled refrigerant leaks in 4 minutes. The lowest concentration at which the leaked flammable gas can be mixed with air and burned by ignition is called the lower flammable limit (LFL). In the case of propane, the lower flammable limit is 2.1 vol%.

[0042] In the machine room 20, an air flow is generated by the condenser blower 6. Therefore, the refrigerant leaking from the discharge pipe 34 is carried along by the air flow. If the air volume of the condenser blower 6 is maintained at a volume that keeps the propane concentration below 2.1 vol%, which is the lower flammable limit, around and inside the control device 7 in which the electrical components are stored, the possibility of propane igniting and combustion can be suppressed.

[0043] Therefore, as a countermeasure against refrigerant leakage, the condenser blower 6 is required to maintain an air volume equal to or greater than the required volume at which the concentration of the propane refrigerant in the machine room 20 becomes equal to or less than 2.1 vol.%, the lower flammability limit of propane, in the event of a refrigerant leakage.

[0044] The air volume of the condenser fan 6 can be calculated using the formula proposed by Colbourne. The following formula (1) represents the Colbourne formula.

[0045]

number

[0046] In formula (1), the outlet area A0 is a×b, which is the product of the height dimension a of the condenser 3 and the fin stack length dimension b in Fig. 1. If the air volume of the condenser blower 6 is maintained at the air volume calculated by the formula proposed by Colbourne, the refrigerant concentration can be suppressed to below the lower flammability limit even if the refrigerant leaks.

[0047] If the condenser 3 is used continuously, the condenser 3 becomes clogged, and the air volume blown from the condenser blower 6 and passing through the condenser 3 decreases. In the formula proposed by Colbourne, it is proposed to set the air volume obtained by multiplying the blown air volume Q by 0.464 as the critical air volume, taking into consideration the clogging of the condenser 3. The critical air volume is the minimum air volume required to keep the refrigerant concentration below the lower combustion limit. Here, the set air volume in the present embodiment 1 is synonymous with the critical air volume, and is the minimum air volume required to keep the refrigerant concentration below the lower combustion limit in the machine room 20. Here, the inside of the machine room 20 includes the machine room 20 and a predetermined surrounding spatial area of ​​the showcase 1. The predetermined surrounding spatial area of ​​the showcase 1 includes, for example, a predetermined spatial area in front of the showcase. In addition, the control device 7 is configured to output an alarm of air volume decrease abnormality that notifies that the air volume of the condenser blower 6 falls below the critical air volume when the critical air volume cannot be maintained due to clogging of the condenser 3. By outputting an alarm for abnormal decrease in air volume, it is possible to prevent the showcase 1 from continuing to operate in a state in which the critical air volume cannot be maintained. In the case of a vertical open showcase, since an air curtain is always formed over the entire front surface, it is considered that a flammable area will not be generated within the main body 1a due to leakage from inside the showcase, that is, leakage of refrigerant from the evaporator 5.

[0048] <Air volume control of condenser fan 6> FIG. 6 is a diagram showing a control board 6f incorporated in the condenser blower 6 of the showcase 1 according to the embodiment and a main board 7a of the control device 7. As shown in FIG.

[0049] The condenser blower 6 is a DC (Direct current) brushless blower. The interior blower 15 also uses a DC brushless blower. The DC brushless blower does not have a brush structure and does not have a contact structure inside. In a brush motor having a brush structure, electrical opening and closing occurs at the brush part during the coil rotation process, which may cause sparks, so care must be taken when applying it to equipment using a flammable refrigerant. In contrast, a DC brushless motor does not rotate the coil and does not have a brush part, so no electrical opening and closing occurs. Therefore, a DC brushless blower using a DC brushless motor is safe even if a flammable refrigerant is used.

[0050] As shown in FIG. 6, the control board 6f of the condenser blower 6 is connected to the main board 7a of the control device 7 by five control lines 6a to 6e. The wire 6a supplies the drive voltage Vs for driving the condenser blower 6 to the control board 6f. The drive voltage Vs is, for example, DC 280V. The wire 6b is a ground line GND or earth line GND that is a reference potential for the control voltage Vcc and the speed control voltage Vsp. The wire 6c supplies the control voltage Vcc to the control board 6f. The control voltage Vcc is, for example, DC 15V. The wire 6d supplies the speed control voltage Vsp to the control board 6f. The speed control voltage Vsp is, for example, in the range of DC 0 to 6V. The wire 6e feeds back a rotation speed signal FG indicating the rotation speed of the condenser blower 6 to the main board 7a. A current sensor 28 is disposed in the line supplying the drive voltage Vs.

[0051] By controlling the rotation speed of the condenser blower 6, the air volume by the condenser blower 6 is maintained at or above the critical air volume. Therefore, even if a refrigerant leak occurs in the machine room 20, the operation of the condenser blower 6 is controlled. Then, the condenser blower 6 diffuses the leaked refrigerant, so that the refrigerant concentration in the machine room 20 is maintained at or below the lower flammability limit.

[0052] <Relationship between rotation speed, speed control voltage Vsp, and operating current value due to aging> FIG. 7 is a diagram showing the relationship between the rotation speed of the condenser blower 6, the speed control voltage Vsp, and the operating current value in the showcase 1 according to the embodiment.

[0053] As shown in Fig. 7, the air volume passing through the condenser blower 6 decreases from the initial value due to clogging of the condenser 3 caused by aging. When the air volume passing through the condenser blower 6 decreases, the rotation speed of the DC brushless motor of the condenser blower 6 decreases, and the load acting on the DC brushless motor decreases. When the rotation speed of the condenser blower 6 decreases, the speed control voltage Vsp increases and the operating current value of the condenser blower 6 increases, whereby the condenser blower 6 is controlled to maintain an air volume equal to or greater than the critical air volume.

[0054] For example, in the case of a vertical open showcase with a width of 2 feet, the initial operating current value of the condenser fan 6 is about 57 mA. When the condenser 3 becomes clogged, the current value is increased to, for example, about 67 mA in order to obtain the limit air volume.

[0055] If the amount of air sent by the condenser blower 6 decreases due to a malfunction such as clogging in the condenser 3 and falls below the critical air amount, an alarm is output.

[0056] In this way, the condenser blower 6 is operated to maintain the preset critical airflow and rotation speed. When the condenser 3 becomes clogged, the condenser blower 6 is operated with the speed control voltage Vsp increased and the operating current value of the condenser blower 6 increased so that the rotation speed does not drop below the critical airflow due to the reduction in airflow. When an abnormality of reduced airflow, in which the airflow of the blower falls below the critical airflow, is detected, an alarm is output.

[0057] As the condenser blower 6 deteriorates over time, eventually the airflow rate of the condenser blower 6 is no longer maintained at the critical airflow rate, and if a refrigerant leak occurs, the concentration may reach a flammable concentration. By outputting the alarm, the user can recognize that a malfunction such as clogging has occurred in the condenser 3. In addition, by outputting the alarm, the user can recognize that if a refrigerant leak occurs, the concentration of the flammable refrigerant may reach a flammable concentration.

[0058] <Relationship between power supply voltage Vdc and operating current value> FIG. 8 is a diagram showing the relationship between the power supply voltage Vdc of the showcase 1 according to the embodiment and the operating current value of the condenser blower 6. As shown in FIG.

[0059] A possible method for detecting an airflow reduction abnormality in which the airflow of the condenser blower 6 falls below the critical airflow is, for example, to detect the abnormality based on the operating current value of the condenser blower 6. When the airflow passing through the condenser blower 6 decreases, the rotation speed of the DC brushless motor decreases, and the operating current value of the condenser blower 6 is configured to increase with the decrease in the rotation speed of the DC brushless motor. The increase in the operating current value can be detected by an increase in the output voltage of the current sensor 28.

[0060] Furthermore, in detecting an increase in the operating current value, the control device 7 stores the operating current value of the condenser blower 6 measured in a trial run performed before the actual operation as an initial operating current value in the memory 7b inside the control device 7. In the actual operation, the control device 7 detects an abnormality in the air volume decrease of the condenser blower 6 based on the initial operating current value stored in the memory 7b and the operating current value measured by the current sensor 28, and outputs an alarm. Specifically, when the operating current value of the condenser blower 6 exceeds an abnormality determination value A3 obtained by adding a preset increase value to the initial operating current value, it is possible to detect the occurrence of an abnormality in the air volume decrease. Since an abnormality in the air volume decrease is detected based on the initial operating current value and the operating current value during the actual operation, it is possible to perform detection taking into account product variations.

[0061] As shown in FIG. 8, the power supply voltage Vdc at the store installation site is allowed to vary by ±10% from the rated voltage of 100V, and therefore varies from 90V to 110V depending on the power demand situation. In a 2-foot vertical open-type showcase 1, the operating current value of the condenser fan 6 at the rated voltage of 100V is assumed to be 57mA. In this case, if the power supply voltage Vdc is 90V, the operating current value of the condenser fan 6 is approximately 63mA. Also, if the power supply voltage Vdc is 110V, the operating current value of the condenser fan 6 is approximately 52mA, and the operating current value of the condenser fan 6 varies depending on the power supply voltage Vdc.

[0062] For example, assume that the operating current value of the condenser blower 6 at the critical airflow is 67 mA. In this case, if the initial operating current value of the condenser blower 6 at the rated voltage of 100 V is 57 mA, there is a difference of about 10 mA between the initial operating current value and the operating current value at the critical airflow. On the other hand, if the initial operating current value of the condenser blower 6 at the rated voltage of 90 V is 63 mA, the difference between the initial operating current value and the operating current value at the critical airflow decreases to 4 mA. Depending on the power supply voltage Vdc when the initial operating current value is measured, an alarm notifying an abnormality in reduced airflow may be erroneously issued if the operating current value of the condenser blower 6 drops by only 4 mA from the initial operating current value.

[0063] In this way, the current value of the fan motor of the condenser blower 6 used in the showcase 1 varies depending on factors such as the power supply to the showcase 1 or the power consumption of the showcase 1 itself.

[0064] The following (a) to (c) are examples of specific factors that cause the power supply voltage Vdc of the fan motor to fluctuate. (a) Fluctuations in the power supply voltage Vdc during manufacturing or shipping inspection Voltage fluctuation during shipping inspection: Fluctuation range: approx. 10V (b) Fluctuations in power supply voltage Vdc at the installation site or store - Distance from the store to the power source (the greater the power path impedance, the greater the voltage fluctuations) Seasonal fluctuations (when supply margins decrease due to fluctuations in electricity demand, voltage drops) (c) Voltage fluctuations within the store - Power wiring at the store installation location (the voltage will drop if multiple power strips are used) - Operation of other equipment in the store (e.g. defrosting of other showcases and the subsequent increase in power consumption due to rapid cooling) However, the period of voltage fluctuations caused by other devices in the store can be estimated to be shorter than 30 minutes based on measurements at a representative store and the results of a provisional measure that extended the abnormality determination time to 30 minutes.

[0065] When factors that cause the power supply voltage Vdc of the fan motor of the condenser blower 6 to fluctuate are compounded, the decrease in the operating current value is not properly detected. As described above, in detecting the airflow decrease abnormality, the threshold value is set to a value obtained by adding the initial current value to the increase value. The increase value is preset as a current value that is a set airflow that is a minimum airflow required to maintain a state below the lower combustion limit at a specified voltage. For example, the increase value in the showcase 1 with a rated voltage of 280V is 7mA. In this case, the threshold value does not compensate for the fluctuation of the current value measured initially or the fluctuation of the current value in the usage environment. Therefore, there are cases where an alarm is erroneously issued even though the operating current value of the condenser blower 6 at the critical airflow is not yet at an abnormal level, or where an alarm notifying the airflow decrease abnormality is not output even though the operating current value has decreased to an abnormal level.

[0066] More specifically, the relationship between the input and output of the fan motor of the condenser blower 6 is as follows. η·Win=Wout η: motor efficiency, Win: motor input, Wout: motor output Win=V·I V: Motor power supply voltage Vdc, I: Motor current (average value) Wout=2π R / 60 T R: Motor speed (rpm), T: Torque N m

[0067] In this case, it is assumed that the conditions (d) to (f) are met. (iv) The standard showcase 1 is a showcase 1 with a current value of 50 mAdcave when the frequency of the compressor 2 is 40 Hz and the power supply voltage Vdc is 100 Vac. The total converter power consumption including the compressor 2 is 1 kW. (e) The power source for the fan motor is the power source for the showcase 1 converted to DC by a converter, so that under normal power usage conditions, the voltage converted to DC is proportional to the power source voltage Vdc. The power converted by the converter and half of the power cycle time is only discharging. Therefore, the voltage drop during that time is simplified using the current consumption, the time of the half cycle, and the capacitor capacity (2200 μF) to determine the voltage drop, and the point at which the converter power supply voltage and current are balanced is defined as the power supply voltage Vdc of the condenser blower 6. CV=Q=It (F) The efficiency η of a fan motor is shown to vary with torque in the motor specifications. Therefore, even if the output is different, the efficiency will be the same if the torque is the same.

[0068] Also, when the rotation speed R of the fan motor is constant, for example, 1600 rpm, and the pressure loss and torque are constant, the output Wout is constant. Therefore, assuming the above conditions, the fan motor current will fluctuate by about 0.7 mA / V when the power supply voltage Vdc of the showcase 1 fluctuates by 1 V. In this way, when the airflow reduction abnormality of the condenser blower 6 is detected based only on the operating current value of the condenser blower 6, it is difficult to respond to differences in the power supply voltage conditions at the store installation location. For this reason, the airflow reduction abnormality in the airflow of the condenser blower 6 is detected based on the power value, not the current value of the condenser blower 6.

[0069] <Conversion of current value to power value> The power value of the condenser fan 6 can be calculated by measuring the drive voltage value Vs of the condenser fan 6, which corresponds to the power supply voltage Vdc at the store installation location, and multiplying it by the operating current value of the condenser fan 6.

[0070] As explained in the above item (f), if the load on the fan motor of the condenser blower 6 is constant, the power input to the condenser blower 6 is constant. In the power value which is the product of the fluctuating power supply voltage Vdc and the current I, the influence of the fluctuation in the power supply voltage Vdc is cancelled. Therefore, the limit airflow is grasped based on the abnormality determination value A3 calculated based on the power value of the condenser blower 6, and an abnormality of a decrease in the airflow of the condenser blower 6 is detected.

[0071] <How to detect abnormal decrease in airflow> Since there is variation in the power supply voltage Vdc, the abnormality determination value A3 is calculated taking into account the effect of variation by performing a trial run before actual operation as described above so that the airflow reduction abnormality can be accurately detected. During the trial run, the operating current value of the condenser blower 6 varies by about several mA depending on the fan combination or the condenser 3 settings, etc., so an initial value is set for each product during the trial run and registered as initial data. The trial run is performed, for example, when the product is assembled or when it is shipped from the factory.

[0072] In the trial operation, the current sensor 28 measures the initial operating current value of the condenser blower 6. The initial operating current value is integrated with the initial driving voltage value stored in the main board 7a of the control device 7. As a result, an initial operating power value A1 is calculated and recorded and stored in the memory 7b inside the control device 7. The initial operating current value and the initial driving voltage value, which are the initial data, are measured after the compressor 2 and the condenser blower 6 are started and the operation of the compressor 2 and the condenser blower 6 is in a determined state. Since the power is used to detect the air volume reduction abnormality, it is sufficient that the initial operating power value A1, which is the product of the initial driving voltage value and the initial operating current value, is recorded in the memory 7b. However, it is preferable that the power supply voltage Vdc and the initial operating current value are recorded as original data in anticipation of future analysis at the time of a failure.

[0073] Next, during actual operation, the air volume of the condenser blower 6 in use is measured and a judgment is made. During actual operation, an actual operating power value of the condenser blower 6 is calculated from the product of the operating current value measured by the current sensor 28 and the drive voltage. An air volume drop abnormality of the condenser blower 6 is detected based on the actual operating power value and the initial operating power value A1 stored in the memory 7b of the control device 7. When the actual operating power value of the condenser blower 6 becomes equal to or greater than a preset abnormality judgment value, it is judged that the air volume is below the limit air volume, and an alarm is output to notify of the air volume drop abnormality.

[0074] <Flow of determining the abnormality judgment value used to detect the decrease in airflow (during assembly)> FIG. 9 is a flowchart for determining an abnormality judgment value used for detecting an abnormality in the air volume decrease of the condenser blower 6 when assembling the showcase 1 according to the embodiment.

[0075] 9, during a test run, the control device 7 calculates an initial operating power value A1 of the condenser blower 6 from the product of the initial operating current value and the initial drive voltage of the condenser blower 6. When the control device 7 starts calculating the initial operating power value A1, it starts the operation of a timer built into the control device 7 (step ST102 in FIG. 9) to measure the time from the start of operation.

[0076] The timing for starting the operation of the timer is, for example, when the operation of the showcase 1 is started (step ST101 in FIG. 9), the compressor 2 and the condenser blower 6 are started, and then the operation of the compressor 2 or the condenser blower 6 is in a predetermined state. The predetermined state is, for example, when 30 seconds have passed after the operation of the compressor 2 is started, or when 30 seconds have passed after the compressor 2 reaches the maximum rotation speed.

[0077] When the timer measurement time has elapsed for a first predetermined time B1 (YES in step ST103 in FIG. 9), the control device 7 calculates a sampled power value (step ST104 in FIG. 9). The sampled power value is calculated by sampling the operating current value of the current sensor 28 and the driving voltage value Vs of the condenser blower 6, and integrating the operating current value and the driving voltage value Vs. The operating current value of the current sensor 28 is an A / D conversion determined value. Sampling is performed every second predetermined time B2. The second predetermined time B2 is, for example, 9 seconds, which is the communication cycle of the inverter microcomputer. The driving voltage value Vs may be the bus voltage of the IPM board. Sampling is performed a first predetermined number of times, N1 times, for example, 4 times.

[0078] The control device 7 calculates the average value of the sampled power values ​​obtained by sampling N1 times, and sets the average value as the initial operating power value A1 (step ST105 in FIG. 9). The sampled power values ​​are, for example, four sampled power values ​​obtained over 36 seconds from the start of sampling.

[0079] For example, when the initial operating current value is 57 mA and the drive voltage value Vs is 280 V, the control device 7 calculates 15,960 mAV as the initial operating power value A1 from 57 mA×280 V. The calculation result is recorded and stored as the initial operating power value A1 on the main board 7a of the control device 7 (step ST106 in FIG. 9). The calculated initial operating power value A1 is stored in, for example, an E2PROM in the memory 7b.

[0080] Next, the control device 7 adds the abnormality determination increment value A2 to the initial operating power value A1 to determine the abnormality determination value A3 (step ST107 in FIG. 9). The abnormality determination value A3 is a power value corresponding to the set air volume. The abnormality determination increment value A2 is a value obtained by multiplying the current value of the condenser fan 6 measured in advance by the power supply voltage at the site where the condenser fan 6 is installed. This current value of the condenser fan 6 measured in advance is a current value obtained by subtracting the initial operating current value from the set current value, which is the current value at which the condenser fan 6 reaches the set air volume, and is obtained by performing a test for each model or model number of the showcase 1. The current value of the condenser fan 6 measured in advance is a characteristic value such as 7 mA. The power supply voltage varies within a range of, for example, 280V×90% to 180V×110%. Therefore, the abnormality determination increment value A2 varies with the power supply voltage even for the same showcase 1. The abnormality determination value A3 further varies with the current value or voltage value variation due to the parts of the showcase 1 or product error occurring during assembly. For example, if the current value is 67mA when the air volume of the condenser fan 6 is the limit air volume, the abnormality determination increment value A2 is 2800mAV, which is the product of 10mA, which is the increment from the initial operating current value of 57mA, and 280V, which is the drive current. Therefore, the abnormality determination value A3 is 67mA×280V+10mA×280V, which is the sum of the abnormality determination increment value A2 and the initial operating power value A1, and is 18760mAV. For example, the initial operating current value is 67mA to obtain the limit air volume at 57mA, so that the value is (67 / 57)×100=117.5(%). From this, the abnormality determination increment value A2 may be set to, for example, 16% or 17% of the initial operating power value A1.

[0081] The initial operating power value A1 of the showcase 1 is calculated when the product is assembled, and the product is shipped with the initial operating power value A1 and the abnormality determination value A3 stored in the memory 7b. Since the memory 7b is a non-volatile memory, the initial operating power value A1 is held in the memory 7b even if the power of the showcase 1 is turned off.

[0082] <Flow of detecting abnormal decrease in airflow (during actual operation of the showcase)> 10 is a flow chart for detecting an abnormality in the decrease in air volume of the condenser fan 6 during actual operation of the showcase 1 according to the embodiment. During actual operation means during normal use.

[0083] As shown in Fig. 10, when actual operation starts in the showcase 1 installed in the market (step ST201 in Fig. 10), the control device 7 periodically detects an actual operation power value of the condenser fan 6 (step ST202 in Fig. 10). The actual operation power value is calculated from the product of the operation current value of the condenser fan 6 input to the main board 7a, which is measured by the current sensor 28 of the condenser fan 6, and the drive voltage of the condenser fan 6.

[0084] The control device 7 detects an abnormality of a decrease in the air volume of the condenser blower 6 by comparing the calculated actual operation power value with the abnormality determination value A3 stored in the memory 7b of the control device 7. Specifically, the control device 7 judges whether the actual operation power value of the condenser blower 6 is equal to or greater than the abnormality determination value A3 (step ST203 in FIG. 10). The control device 7 detects an abnormality of a decrease in the air volume of the condenser blower 6 when the actual operation power value is equal to or greater than the abnormality determination value A3 (YES in step ST203 in FIG. 10) and is continuously judged to be equal to or greater than the abnormality determination value A3 for a second predetermined number of times, N2 times (YES in step ST204 in FIG. 10).

[0085] When an abnormality in the decrease in air volume is detected in the condenser blower 6, the control device 7 outputs an alarm for the abnormality in the decrease in air volume (step ST205 in FIG. 10).

[0086] In this way, since the airflow reduction abnormality is detected based on the initial operating power value A1 and the abnormality determination value A3, even if there is a fluctuation in the power supply voltage Vdc, the airflow reduction abnormality can be accurately detected and an alarm can be output to notify the airflow reduction abnormality with high accuracy. Therefore, it is possible to prevent a situation in which operation is continued without noticing that the airflow of the condenser blower 6 is in a state where it cannot maintain the critical airflow, causing the refrigerant concentration in the machine room 20 to exceed the lower flammability limit, and as a result, safety against refrigerant leakage can be ensured. In addition, since the initial operating power value A1 is obtained by performing a trial run, the airflow reduction abnormality can be accurately detected even if there is a product variation of the condenser blower 6 or a voltage variation at the installation location.

[0087] In addition, the control device 7 may be configured to determine whether or not an abnormality has occurred due to a decrease in air volume when the actual operating power value detects the abnormality determination value A3 a predetermined number of times in a continuous manner, but may also be configured to determine whether or not an abnormality has occurred due to a decrease in air volume in the following manner, taking into account fluctuations in the power supply voltage Vdc at the site.

[0088] The control device 7 periodically, for example, every 9 seconds, or constantly, calculates an actual operating power value by integrating the operating current value of the condenser blower 6 and the drive voltage value Vs of the condenser blower 6. The control device 7 adds +1 to the number counter if the actual operating power value exceeds the abnormality determination value A3, and adds -1 if the actual operating power value is less than the abnormality determination value A3, and outputs an alarm of an abnormality in decreased air volume if the number counter reaches a predetermined value or more.

[0089] In addition, it is preferable to perform sampling of the value of the current sensor 28 and the drive voltage value Vs by synchronizing the measurement timing of the value of the current sensor 28 and the drive voltage value Vs. By simultaneously measuring the current sensor value and the drive voltage value Vs, it is possible to prevent a time lag that occurs when the drive voltage value Vs of the fan is measured successively after measuring the current sensor value.

[0090] Also, sampling should not be performed during the transitional period of starting or stopping the compressor 2. This is because during the transitional period of starting or stopping the compressor 2, the initial operating current value or the initial driving voltage value may be higher or lower than the value during normal operation.

[0091] Furthermore, the control device 7 may be configured to reset the initial driving power value by performing an operation similar to a trial run when starting up the showcase 1. By updating the initial driving power value, it is possible to detect an abnormality in the reduction in air volume corresponding to the voltage variation at the installation location.

[0092] In addition, due to the configuration of the main board 7a, when the compressor 2 operates, the drive voltage value Vs of the condenser blower 6 may decrease. This is because, in an AC power source, current cannot be supplied to the busbar near the zero crossing where the voltage value approaches zero, so during that period the compressor 2 is driven only by the smoothing capacitor, and the drive voltage of the condenser blower 6 fluctuates depending on whether the compressor 2 is operating or not. When the compressor 2 operates, the drive voltage value Vs of the condenser blower 6 decreases, so the operating current value of the condenser blower 6 increases compared to when the compressor 2 is stopped. For this reason, the abnormality determination value A3 may be changed depending on whether the compressor 2 is operating or not, by determining whether the compressor 2 is operating or not.

[0093] In the showcase 1 in Fig. 1, the condenser 3 is arranged so that the drain water evaporator 22 can be maintained from the front 1b side of the showcase 1. Specifically, in Fig. 1, the condenser 3 and the drain water evaporator 22 are arranged side by side on the left and right sides when viewed from the front 1b. Therefore, when an operator removes the drain water evaporator 22 from the main body 1a, the operator can remove the drain water evaporator 22 without being hindered by the condenser 3. The showcase 1 is not limited to such an arrangement, and for example, the condenser 3 may be arranged so that the suction surface of the condenser 3 faces the front 1b.

[0094] The airflow decrease abnormality in the interior blower 15 is detected when the airflow of the interior blower 15 falls below a preset second set airflow, for example. Since clogging of the evaporator 5 occurs, for example, when frost forms on the evaporator 5, if the airflow decrease abnormality in the interior blower 15 can be detected, it is possible to detect the timing of defrosting based on the airflow decrease abnormality, rather than based on the accumulated operating time of the compressor 2, etc. Based on the detection of the airflow decrease abnormality in the interior blower 15, a defrosting operation is started and the frost on the evaporator 5 is removed.

[0095] <Variation 1> Fig. 11 is a schematic diagram showing a first modified example of the showcase 1 according to the embodiment. As shown in Fig. 11, the showcase 1 according to the first modified example includes a current detection circuit 77 instead of the current sensor 28. The current detection circuit 77 is provided in the main board 7a, and is connected to a shunt resistor 78 that detects the current of the condenser blower 6 acting as a load. Since the current detection circuit 77 is provided on the main board 7a, it is easy to install it even in a crowded structure around the condenser 3.

[0096] <Variation 2> FIG. 12 is a diagram showing the positional relationship between the evaporator 5 and the interior blower 15 of the showcase 1 according to the second modification of the embodiment. The showcase 1 according to the second modification is configured to start a defrosting operation by detecting an abnormality in the decrease in the air volume of the interior blower 15 instead of the operating time of the compressor 2. As shown in FIG. 12, the showcase 1 according to the second modification is provided with a second current sensor 28a that detects the current of the interior blower 15. The second current sensor 28a is configured, for example, to be penetrated by a wiring 15a connecting the interior blower 15 and the control device 7. The detection of the abnormality in the decrease in the air volume of the interior blower 15 can be performed in the same manner as the detection of an abnormality due to the decrease in the air volume of the condenser blower 6.

[0097] Specifically, during a test run, the control device 7 calculates a second initial operating power value from a second initial operating current value detected by a second current sensor 28a disposed on the interior blower 15 and a drive voltage value Vs of the interior blower 15. During actual operation, the control device 7 calculates a second actual operating power value by multiplying the drive power value of the interior blower 15 by the second operating current value measured by the second current sensor 28a. When the control device 7 detects that the second actual operating power value exceeds a second abnormality determination value calculated based on the second initial operating power value, the control device 7 detects that an abnormality in the air volume decrease of the interior blower 15 has occurred. Then, the control device 7 outputs a defrost start signal to start the defrost operation.

[0098] In this manner, the second operating current value detected by the second current sensor 28a disposed in the interior blower 15 and the drive voltage value Vs of the interior blower 15 are measured, and the second actual operating power value is calculated as the product of these values. This makes it possible to detect an abnormality in the reduction in air volume due to clogging of the evaporator 5 based on the second actual operating power value.

[0099] According to the showcase 1 according to the embodiment described above, it is detected that the air volume from the condenser fan 6 falls below the limit air volume, based on the actual operation power value of the condenser fan 6 and the abnormality determination value A3 calculated from the initial operation power value A1, and an alarm is output. This prevents an alarm informing of an abnormality from being output, even though the air volume of the condenser fan 6 has not decreased to a level at which it is determined to be abnormal due to clogging of the condenser 3, due to the influence of fluctuations in the power supply voltage Vdc or the operating current value. In addition, it is possible to prevent a situation in which an abnormal decrease in the air volume of the condenser fan 6 due to clogging of the condenser 3 goes unnoticed due to the influence of fluctuations in the power supply voltage Vdc or the operating current value. This ensures safety against refrigerant leakage in the refrigeration device.

[0100] Furthermore, since the initial operating power value A1 is calculated based on the initial operating current value measured in a test run performed before actual operation, the influence of fluctuations in the operating current value of the condenser blower 6 can be suppressed.

[0101] In addition, the operating current value is increased so that the condenser fan 6 does not fall below the set air volume. Therefore, even if the condenser 3 becomes clogged, the current value of the condenser fan 6 is increased so that the air volume of the condenser fan 6 is equal to or greater than the set air volume.

[0102] Furthermore, the control device 7 detects an abnormality of decreased air volume when the actual operating power value exceeds the abnormality determination value A3 for a first predetermined time B1. This reduces the possibility that an abnormal decrease in the air volume of the condenser blower 6 will be detected when the actual operating power value exceeds the abnormality determination value A3 transiently.

[0103] Furthermore, since the initial operating power value A1 is the average value of the products of multiple initial operating current values ​​and multiple initial drive voltage values, the effects of fluctuations in the initial operating current values ​​and initial drive voltage values ​​are leveled out.

[0104] In addition, since the initial operating power value A1 is obtained by sampling the initial operating current value and the initial driving voltage, which are synchronized, the initial operating current value and the initial driving voltage value are measured under the same conditions, which reduces the effect of fluctuations in the initial operating current value or the initial driving voltage value on the initial operating power value A1.

[0105] Moreover, the initial operating power value A1 is obtained from the initial operating current value and the initial drive voltage measured at a time other than when the compressor 2 is started or stopped. This eliminates transient fluctuations in the initial operating current value and the initial drive voltage value, making it possible to accurately detect an abnormal decrease in the airflow rate of the condenser blower 6.

[0106] Furthermore, the control device 7 is configured to determine whether the compressor 2 is operable, and to update the abnormality determination value A3 depending on whether the compressor 2 is operable. When the compressor 2 is operating, the operating current value of the condenser blower 6 increases compared to when the compressor 2 is stopped. By updating the abnormality determination value A3 depending on whether the compressor 2 is operable, an abnormal decrease in the air volume of the condenser blower 6 can be detected more accurately.

[0107] The showcase 1 also includes an interior blower 15 that blows air toward the evaporator 5, and a second current sensor 28a that measures a second operating current value, which is a current value during operation of the interior blower 15. The control device 7 starts a defrosting operation when it detects that the air volume of the interior blower 15 falls below a second set air volume, which is set in advance, based on a second actual operating power value acquired by integrating the drive voltage value of the interior blower 15 with the second operating current value measured by the second current sensor 28a during actual operation. In other words, the control device 7 is configured to start a defrosting operation when the air volume of the interior blower 15 that blows air toward the evaporator 5 falls below the second set air volume. As a result, the control device 7 detects clogging due to frost on the evaporator 5 from the second actual operating power value of the interior blower 15, and can use it as a defrosting start signal.

[0108] Furthermore, a flammable or slightly flammable refrigerant is used as the refrigerant, and even if the flammable or slightly flammable refrigerant leaks, it is possible to prevent a flammable region from being formed within the main body 1a. [Explanation of symbols]

[0109] 1 showcase, 1a main body, 1b front, 1c rear, 1d right side, 1e left side, 2 compressor, 3 condenser, 4 throttling device, 5 evaporator, 6 condenser blower, 6a, 6b, 6c, 6d, 6e wiring, 6f control board, 7 control device, 7a main board, 7b memory, 8 insulating wall, 9 inner layer partition plate, 10 inner layer duct, 10a ceiling, 11 storage room, 12 shelf, 13 fluorescent lamp, 14 bottom duct, 15 interior blower, 15a wiring, 16 front opening, 17 outlet, 18 suction port, 19 bottom partition plate, 20 machine room, 21 drain pan, 21a drain outlet, 22 drain water evaporation device, 23 evaporation dish, 24 evaporation plate, 25 , 26 operation panel, 27 support member, 28 current sensor, 28a second current sensor, 30 high pressure pressure switch, 31 night cover, 33a, 33b partition plate, 34 discharge pipe, 40 refrigerant circuit, 77 current detection circuit, 78 shunt resistor.

Claims

1. a main body in which a compressor, a condenser, a throttling device, and an evaporator are connected by piping and in which a refrigerant flows; a condenser blower disposed in a machine chamber partitioned so that the condenser is disposed in the main body; a control device that controls an operating current value of the condenser blower so that a set air volume is maintained, which is a minimum air volume required to keep the concentration of the refrigerant in the machine room at or below the lower flammability limit, by operating the condenser blower; Equipped with The control device includes: and detecting that the air volume of the condenser blower has fallen below the set air volume based on an actual operating power value and an abnormality determination value corresponding to the set air volume, The control device further comprises: Determining whether the compressor is operating or not; The abnormality determination value is changed depending on whether the compressor is operating or not. Refrigeration equipment.

2. The abnormality determination value is calculated based on an initial operating power value of the condenser blower and a preset abnormality determination increment value.

2. The refrigeration system of claim 1.

3. The initial operating power value is obtained by integrating a previously measured initial operating current value of the condenser blower and an initial driving voltage value of the condenser blower corresponding to the initial operating current value.

3. The refrigeration system of claim 2.

4. The initial operating power value is The initial operating current value and the driving voltage value are obtained from the initial operating current value and the driving voltage value measured at a time other than when the compressor is started or stopped.

4. The refrigeration system of claim 3.

5. A compressor, a condenser, a throttling device, and an evaporator are connected by piping to a main body in which a refrigerant circuit is arranged and through which a refrigerant flows; a condenser blower disposed in a machine chamber partitioned so that the condenser is disposed in the main body; a control device that controls an operating current value of the condenser blower so that a set air volume is maintained, which is a minimum air volume required to keep the concentration of the refrigerant in the machine room at or below the lower flammability limit, by operating the condenser blower; Equipped with The control device includes: and detecting that the air volume of the condenser blower has fallen below the set air volume based on an actual operating power value and an abnormality determination value corresponding to the set air volume, the abnormality determination value is calculated based on an initial operating power value of the condenser blower and a preset abnormality determination increment value; The initial operating power value is an initial operating current value of the condenser blower, which is measured in advance, and an initial driving voltage value of the condenser blower, which corresponds to the initial operating current value, are integrated to obtain the initial operating current value; and, The initial operating current value and the driving voltage value are obtained from the initial operating current value and the driving voltage value measured at a time other than when the compressor is started or stopped. Refrigeration equipment.

6. The abnormality determination increment value is a value obtained by multiplying a previously measured current value of the condenser blower by a power supply voltage at the site where the device is installed. The refrigeration apparatus according to any one of claims 3 to 5.

7. The previously measured current value of the condenser blower is a value obtained by subtracting the initial operating current value from a current value at which the air volume of the condenser blower becomes the set air volume. The refrigeration apparatus according to any one of claims 3 to 6.

8. The initial operating current value is measured during a trial run before the actual operation. The refrigeration apparatus according to any one of claims 3 to 6.

9. The initial operating power value is The average value of the products of the initial operating current values ​​and the driving voltage values ​​measured during a second predetermined time period is The refrigeration apparatus according to any one of claims 3 to 6.

10. The initial operating power value is a plurality of synchronized samplings of the initial operating current values ​​and a plurality of synchronized samplings of the driving voltage values; The refrigeration apparatus according to any one of claims 3 to 6.

11. The control device increases an operating current value of the condenser blower so that the air volume of the condenser blower does not fall below the set air volume. A refrigeration apparatus according to any one of claims 1 to 10.

12. The control device detects that the air volume of the condenser blower has fallen below the set air volume when the actual operating power value continues to exceed the abnormality determination value for a predetermined number of times. A refrigeration apparatus according to any one of claims 1 to 11.

13. The control device includes: When the air volume of the condenser blower falls below the set air volume, an alarm is output. A refrigeration apparatus according to any one of claims 1 to 12.

14. a current sensor for measuring the operating current value, which is a current value during operation of the condenser blower. The actual operation power value is obtained by multiplying the operating current value measured by the current sensor during actual operation by the driving voltage value of the condenser blower. A refrigeration apparatus according to any one of claims 1 to 13.

15. Further comprising an indoor fan that blows air toward the evaporator, and a second current sensor that measures a second operating current value that is a current value during operation of the indoor fan, The control device includes: When it is detected that the air volume of the indoor fan falls below a preset second set air volume based on a second actual operation power value obtained by integrating the second operating current value measured by the second current sensor during actual operation with the drive voltage value of the indoor fan, a defrosting operation is started. A refrigeration apparatus according to any one of claims 1 to 14.

16. The refrigerant is a flammable refrigerant or a slightly flammable refrigerant. A refrigeration apparatus according to any one of claims 1 to 15.

17. A showcase comprising the refrigeration device according to any one of claims 1 to 16.

Images