Cooling storage

Abstract

This design suppresses the rise in internal temperature during defrosting while also limiting the increase in the number of parts. [Solution] The cooling storage unit 10 comprises a plurality of coolers 21 connected in parallel, a compressor 24, a condenser 25, a plurality of electronic expansion valves 27 provided between the condenser 25 and each cooler 21, which reduce the pressure of the refrigerant from the condenser 25 and turn the supply of refrigerant to the coolers 21 on and off, and a defrosting means 32 provided for each cooler 21. When the control unit 60 operates the plurality of defrosting means 32 to perform a defrosting operation, it operates the compressor 24 and, instead of operating all the defrosting means 32 at the same time, operates one or more of the defrosting means 32, turning on the electronic expansion valve 27 connected to the cooler 21 on which the stopped defrosting means 32 is provided, while turning off the other electronic expansion valves 27.

Description

Technical Field

[0001] This technology relates to a cooling refrigerator.

Background Art

[0002] Conventionally, a cooling device in which a plurality of coolers are connected in parallel to one compressor is known, and an example thereof is described in Patent Document 1. The cooling refrigerator described in Patent Document 1 is an open showcase that opens forward, and includes a cooling device in which a main evaporator (main cooler) and an auxiliary evaporator (auxiliary cooler) are connected in parallel to one compressor. The main cooler is used to generate cold air during the cooling operation. The auxiliary cooler is used to cool the air heated by passing through the main cooler during the defrosting operation for removing the frost adhering to the main cooler during the cooling operation. Thereby, it is said that cold air at an appropriate temperature can be blown out into the product display chamber even during the defrosting operation, and the freshness of the products can be maintained.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the main cooler and the sub-cooler described in Patent Document 1, a solenoid valve for supplying and blocking the refrigerant and an expansion part composed of a capillary tube are provided respectively. Therefore, while the rise in the temperature inside the refrigerator during the defrosting operation can be suppressed by providing the sub-cooler, the number of parts and the installation space are significantly increased compared to the case where only the main cooler is provided.

[0005] This technology has been made in view of the above circumstances, and an object thereof is to suppress an increase in the number of parts while suppressing an increase in the temperature inside the refrigerator during the defrosting operation.

Means for Solving the Problems

[0006] To solve the above problems, the cooling storage facility disclosed in this application has the following configuration.

[0007] (1) A storage facility with a storage room, Multiple coolers for cooling the storage chamber, comprising multiple coolers connected in parallel, A compressor for compressing the refrigerant from the aforementioned multiple coolers, A condenser that liquefies the refrigerant gas compressed by the compressor, A plurality of electronic expansion valves are provided between the condenser and each of the coolers, respectively, to reduce the pressure of the refrigerant from the condenser and to switch the supply of refrigerant to the coolers on and off, Each of the aforementioned coolers is provided with a plurality of defrosting means for melting frost that has accumulated on the cooler during cooling operation, It comprises a control unit and, When the control unit operates the plurality of defrosting means to perform a defrosting operation, While operating the aforementioned compressor, Instead of operating all of the aforementioned defrosting means simultaneously, one or more of the aforementioned defrosting means are operated. A cooling storage facility that turns on the electronic expansion valve connected to the cooler equipped with the defrosting means while the other electronic expansion valves are turned off.

[0008] Furthermore, the above configuration can be adapted to various forms as shown below.

[0009] (2) The cooling storage unit according to item (1), wherein the control unit operates the plurality of defrosting means one by one in order when performing the defrosting operation.

[0010] (3) Each cooler is provided with a plurality of cooler fans that circulate the air in the storage room by drawing air from the storage room, passing it through the inside of the cooler, and blowing out the air that has passed through the cooler. When the control unit performs the defrosting operation, it activates the cooler fan for the cooler connected to the electronic expansion valve, which is ON, while stopping the cooler fan for the cooler connected to the electronic expansion valve, which is OFF. The aforementioned multiple coolers are arranged adjacent to each other. A cooling storage unit according to item (1) or (2), wherein a shielding member is provided between adjacent coolers to separate the flow paths of each cooler.

[0011] (4) The cooler is a fin-tube type heat exchanger, Below the cooler, a drain pan is provided to receive the defrost water generated when the frost on the cooler melts. The cooling storage unit according to item (3), wherein the shielding member has a main surface that is sized to cover from the side from the upper end of the end plate of the cooler to the lower end of the drain pan.

[0012] (5) Each cooler is provided with a plurality of cooler fans that circulate the air in the storage chamber by drawing air from the storage chamber, passing it through the inside of the cooler, and blowing out the air that has passed through the cooler. The opening degree of the plurality of electronic expansion valves is variable within a predetermined range. The control unit, After stopping all of the aforementioned defrosting means and ending the defrosting operation, a pre-cooling operation is performed to cool the cooler connected to the on electronic expansion valve by turning on the compressor and one or more of the aforementioned electronic expansion valves without operating all of the aforementioned cooler fans. After the pre-cooling operation, the cooling operation is restarted by activating the multiple cooler fans and turning on the compressor and the multiple electronic expansion valves. A cooling storage unit according to item (1) or (2), wherein when operating the multiple cooler fans to transition from the pre-cooling operation to the cooling operation, the opening degree of all of the multiple electronic expansion valves is set to a constant value for a predetermined time.

[0013] (6) The control unit controls the opening degree of the electronic expansion valve according to the superheat degree of the refrigerant at the refrigerant outlet of the cooler after the elapse of the predetermined time in the refrigerating storage cabinet according to paragraph (5).

[0014] (7) An inlet-side temperature sensor disposed in the refrigerant pipe at the refrigerant inlet of the cooler, and an outlet-side temperature sensor disposed in the refrigerant pipe at the refrigerant outlet of the cooler, and the superheat degree is the difference obtained by subtracting the measured value of the inlet-side temperature sensor from the measured value of the outlet-side temperature sensor in the refrigerating storage cabinet according to paragraph (6).

Advantages of the Invention

[0015] According to the present technology, while suppressing an increase in the number of parts, an increase in the temperature inside the cabinet during the defrosting operation is suppressed.

Brief Description of the Drawings

[0016] [Figure 1] [[ID=二十一]] [Figure 2] Perspective view of the refrigerated showcase according to Embodiment 1 [Figure 3] Cross-sectional perspective view taken along line I-I of FIG. 1 (excluding the cover part) [Figure 4] Cross-sectional perspective view taken along line II-II of FIG. 1 (excluding the cover part) [Figure 5] Cross-sectional perspective view of the refrigerated showcase cut at the position of line III-III of FIG. 3 (excluding the cover part) [Figure 6] Enlarged cross-sectional perspective view of the vicinity of the flap plate in FIG. 4 [Figure 7] Plan view of the frame portion IV in FIG. 3 with the first duct removed [Figure 8] Cross-sectional perspective view showing a shielding plate between adjacent coolers <四三]] [Figure 9] Perspective view of the shielding plate Diagram showing the refrigeration circuit

Modes for Carrying Out the Invention

[0017] <図面の簡単な説明]] ​​A refrigerated display case 10 (an example of a refrigerated storage unit) according to Embodiment 1 will be described with reference to Figures 1 to 9. The symbols F, B, L, R, U, and D shown in each figure indicate the front and rear of the refrigerated display case 10 in the front-to-back direction, the left and right in the width direction (left-to-right direction) when viewed from the front, and the top and bottom in the vertical direction (up and down direction), respectively.

[0018] The refrigerated display case 10 is used, for example, to store stored goods 70 (e.g., ice cream or gelato, see Figure 2) in a frozen state, and to scoop out the frozen stored goods 70 from the storage container 11 (e.g., an ice bin). The refrigerated display case 10 is, for example, a dipping display case installed in an ice cream shop.

[0019] As shown in Figures 1 to 9, the refrigerated display case 10 broadly comprises a horizontally elongated storage body 12, a cover portion 14 that covers the top opening 12S of the storage body 12 from above, a door 15 that forms part of the cover portion 14 and opens and closes the top opening 12S, a machine room 16, a refrigeration circuit 20, and a control unit 60. In this embodiment, the side with the closed door 15 is the rear side (the side facing the staff when installed in a store), and the side opposite the door 15 is the front side (the side facing the customer).

[0020] The cover portion 14 is roughly rectangular in shape with an opening at the bottom and covers the entire top opening 12S of the storage unit body 12 from above. The cover portion 14 is made of a light-transmitting material, so that customers positioned in front of the refrigerated display case 10 and store staff positioned behind it can see the stored items 70 inside the storage container 11 from the outside.

[0021] Door 15 forms the rear wall of the cover portion 14 when closed and is transparent. In this embodiment, two doors 15 are provided side by side. In Figure 1, the left door 15 is shown in the closed state, and the right door 15 is shown in the open state. The upper wall portion 14A of the cover portion 14 has a length in the front-to-back direction that is smaller than the top opening 12S, and the door 15 extends inclined from the rear end portion 14A1 of the upper wall portion 14A to the front edge of the opening of the top opening 12S (counter 45, which will be described later). Door 15 is mounted so as to be able to swing upward around a pivot axis 14B provided on the frame that constitutes the cover portion 14. When opened, door 15 is stored below the upper wall portion 14A.

[0022] As shown in Figures 2 to 4, the storage unit body 12 is an insulated box, and has a structure in which an insulating material 12C made of foamed resin (such as foamed urethane) is filled between an outer box 12A and an inner box 12B, which are assembled from metal plates such as stainless steel into a box shape. The interior of the storage unit body 12 is mostly a storage chamber 13 that houses the storage containers 11. The storage containers 11 are stored throughout the storage chamber 13 (see the dashed line in Figure 2), but in the illustration, some or all of the storage containers 11 are omitted in order to clearly show the inside of the storage chamber 13.

[0023] The storage unit body 12 has a recessed shape at the lower right and lower rear. This recessed area is covered by a panel from the outside of the storage unit body 12, and a machine room 16 is formed between the storage unit body 12 and the panel. The machine room 16 houses the machinery that constitutes the refrigeration circuit 20 (compressor 24, condenser 25, electronic expansion valve 27, etc.) and the control unit 60. The refrigeration circuit 20 will be described in detail later.

[0024] As shown in Figure 3, three first ducts 17 are arranged side by side in the left-right direction at the rear of the storage unit body 12. The area in front of the first ducts 17 within the storage unit body 12 is the storage chamber 13. Behind each first duct 17 (between the first duct 17 and the rear wall 12D of the storage unit body 12), as shown in Figures 4 to 7, a cooler 21 for cooling the storage chamber 13, an internal fan 31 (an example of a cooler fan), a heater 32 (an example of a defrosting means), a drain pan 33, a guide member 34, a flap plate 35 (an example of a flow straightening member), and a shielding member 38 are provided.

[0025] The refrigerated display case 10 is provided with multiple combinations (specifically, three combinations) of these components, and the configuration and arrangement of the components in each combination are basically the same. That is, each combination (each cooler 21) is provided with multiple (specifically two) internal fans 31, heaters 32, drain pans 33, guide members 34, multiple (specifically three) flap plates 35, multiple (specifically two) shielding members 38, and a first duct 17. By providing multiple combinations of coolers 21 and various components to be combined with them, the frozen state of the stored goods 70 can be suitably maintained even when the storage compartment 13 has a large capacity and the door 15 is opened and closed frequently.

[0026] As shown in Figures 3 and 4, the first duct 17 extends vertically, and a predetermined gap is formed between its lower end and the bottom wall 12E of the storage unit body 12. This gap serves as the first intake port 17A for drawing air from the storage chamber 13 into the cooler 21. An outlet port 17B is provided at the upper end of the first duct 17 for blowing the air that has passed through the cooler 21 into the storage chamber 13. The outlet port 17B is a horizontally elongated rectangle and is located near (directly below) the top opening 12S.

[0027] Furthermore, a long, narrow counter 45 is provided between the upper end of the first duct 17 and the top opening 12S of the storage unit body 12. As shown in Figure 5, the counter 45 comprises two metal plates 45A that form the upper and lower surfaces, a resin joint member 45B that connects the metal plates 45A, and an insulating body 45C embedded in the space formed by these. The counter 45 is formed separately from the storage unit body 12 and is attached to the storage unit body 12 in a way that allows it to be attached later (or retrofitted upon request).

[0028] By providing the counter 45, space for a workbench can be secured, and it becomes easier to prevent condensation water from entering the storage unit body 12 or for the removed stored items 70 from falling into the storage unit body 12. In particular, in this embodiment, the rear end of the metal plate 45A on the top surface protrudes upward, which makes it possible to more reliably prevent the intrusion of condensation water and the like.

[0029] The cooler 21 is positioned above the center of the first duct 17 in the vertical direction and has a roughly rectangular parallelepiped shape that is horizontally elongated in the left-right direction. The cooler 21 is a fin-tube type heat exchanger and comprises numerous fins, end plates 21A, and evaporator tubes 21B. The fins are rectangular plate-shaped metal plates arranged at predetermined intervals in the left-right direction, but are omitted in the illustration. The end plates 21A are metal plates provided on both sides of the numerous fins in the arrangement direction (left-right direction). The evaporator tubes 21B extend in the left-right direction and have a U-shaped form, passing through the fins and end plates 21A. The evaporator tubes 21B are connected to the refrigerant tubes 29 of the refrigeration circuit 20. When the liquid refrigerant flowing into the evaporator tubes 21B evaporates and vaporizes into refrigerant gas, the air passing through the cooler 21 is cooled by the heat of vaporization.

[0030] As shown in Figure 7, the three coolers 21 are arranged adjacent to each other in front of the three first ducts 17. In the following, when distinguishing and describing the three coolers 21 by their arrangement, the cooler 21 on the left will be called cooler 21L, the cooler 21 on the right will be called cooler 21R, and the cooler 21 in the middle between them will be called cooler 21M.

[0031] Between adjacent coolers 21, multiple shielding members 38 are provided to separate the flow paths of each cooler 21. The shielding members 38 are attached to both the left and right outer sides (opposite the end plate 21A) of the folded portion (U-shaped portion) of the evaporator tube 21B of the cooler 21, and two are provided for each cooler 21. As shown in Figure 8, the shielding members 38 are plate-shaped members with an L-shaped cross-section, and their main surface 38A is sized and shaped to cover from the side from the upper end 21A1 of the end plate 21A of the cooler 21 to the lower end of the drain pan 33 (more specifically, the drain port 33A on the bottom surface, which will be described later). This ensures that the flow paths of each cooler 21 are reliably separated.

[0032] As shown in Figures 4 and 5, the internal fan 31 is installed above the cooler 21 (on the air outlet side) near the outlet 17B (diagonally downwards). As shown in Figures 6 and 7, two internal fans 31 are installed for each cooler 21, arranged side by side. The internal fan 31 circulates the air in the storage chamber 13 by drawing air in from the storage chamber 13, passing it through the inside of the cooler 21, and blowing out the air that has passed through the cooler 21. The axial direction of the internal fan 31 is along the vertical direction and intersects with the opening direction (horizontal direction) of the outlet 17B. When the internal fan 31 is operating, the air is cooled as it passes through the cooler 21 from bottom to top along the vertical direction (axial direction). Note that if the cooler 21 is small, one internal fan 31 may be installed for each cooler 21, and the number of fans installed is not limited.

[0033] During cooling operation, the internal fan 31 operates, drawing air from the storage chamber 13 through the first intake port 17A. As the air passes through the cooler 21, heat exchange occurs, and the resulting cold air is blown back into the storage chamber 13 through the outlet 17B via the internal fan 31. This circulates air between the storage chamber 13 and the cooler 21, cooling the inside of the storage chamber 13.

[0034] The guide member 34 is provided between the internal fan 31 and the air outlet 17B. The guide member 34 is an inclined plate-shaped member and is provided above and behind the internal fan 31. The guide member 34 changes the direction of the upward-blowing cold air blown by the internal fan 31 so that it is directed towards the air outlet 17B. More specifically, the direction of the cold air blown upward from the internal fan 31 is changed forward towards the air outlet 17B by hitting the inclined guide member 34. The inclination angle of the guide member 34 is set to change the direction of the upward-blowing cold air forward.

[0035] Multiple flap plates 35 are provided near the outlet 17B, between the guide member 34 and the outlet 17B. The flap plates 35 straighten the airflow of the cold air blown by the internal fan 31, directing it toward the outlet 17B. The flap plates 35 straighten the airflow so that the cold air blown by the internal fan 31 and whose airflow direction has been changed by the guide member 34 is blown out horizontally from the outlet 17B.

[0036] In this embodiment, three flap plates 35 are provided and arranged at predetermined intervals. As a result, a total of four gaps (flow straightening spaces) G1 are formed between the opening edge of the air outlet 17B and each flap plate 35. Each flap plate 35 has two flat plate portions 35A and 35B that are connected in the front-rear direction. The front flat plate portion 35A (on the air outlet 17B side) is aligned horizontally, while the rear flat plate portion 35B (on the guide member 34 side) extends diagonally downward so as it approaches the guide member 34.

[0037] The heater 32 is positioned directly below the cooler 21 (on the air inlet side). The heater 32 melts the frost that has accumulated on the cooler 21 by heating. In addition, the frost that has accumulated on the internal fan 31 is also melted as the air heated by the heater 32 rises.

[0038] The drain pan 33 is a horizontally elongated, shallow tray-like structure located below the cooler 21. The drain pan 33 collects the defrost water generated when frost on the cooler 21 and the internal fan 31 melts. A drain port 33A is formed in the center of the drain pan 33 in the left-right direction, and the bottom surface of the drain pan 33 is sloped so that water flows down toward the drain port 33A. The defrost water collected in the drain pan 33 is discharged to the outside through a drain hose.

[0039] Furthermore, a second duct 18 is provided on the front side of the storage unit body 12, as shown in Figures 1, 2, and 4. The second duct 18 has a second intake port 18A formed in the second duct 18 at a position opposite the first outlet port 17B of the first duct 17 in the front-to-back direction. The second intake port 18A is elongated vertically and is provided in large numbers in a row in the left-to-right direction. As previously described, cold air is blown forward horizontally from the first outlet port 17B, but most of this blown-out cold air is drawn into the second intake port 18A. Directly below the top opening 12S, an air curtain of cold air is formed along the opening surface of the top opening 12S, from the first outlet port 17B to the second intake port 18A, thereby improving cooling efficiency.

[0040] The lower end 18B of the second duct 18 is located slightly below the upper end of the containment container 11. The cold air drawn into the second intake port 18A descends from this lower end 18B and diffuses into the storage chamber 13.

[0041] As shown in Figure 9, the refrigeration circuit 20 is a refrigeration cycle in which three coolers 21, an accumulator 23, a compressor 24, a condenser 25, a dryer 26, and an electronic expansion valve 27 are connected by refrigerant pipes 29. The three coolers 21 (left cooler 21L, center cooler 21M, and right cooler 21R) are connected in parallel. The refrigerant gas from the coolers 21 is returned to the compressor 24, which is located downstream in the refrigerant flow direction.

[0042] The compressor 24 uses an electric motor as a power source to draw in and compress refrigerant gas, and discharges high-temperature, high-pressure refrigerant gas to circulate the refrigerant in the refrigeration circuit 20. The condenser 25 cools and liquefies the refrigerant gas compressed by the compressor 24 using airflow from the condenser fan 28. The electronic expansion valve 27 is installed between the condenser 25 and each cooler 21, on the upstream side of each cooler 21 in the refrigerant flow direction. The electronic expansion valve 27 reduces the pressure of the refrigerant from the condenser 25 and switches the supply of refrigerant to the coolers 21 on and off.

[0043] The opening degree of the electronic expansion valve 27 is controlled according to the detection result of the superheat sensor 30. The superheat sensor 30 according to this embodiment consists of an inlet-side temperature sensor 30A located at the refrigerant inlet of the cooler 21 and an outlet-side temperature sensor 30B located at the refrigerant outlet of the cooler 21. The difference ΔT between the two temperature sensors 30A and 30B (the value obtained by subtracting the measured value of the inlet-side temperature sensor 30A from the measured value of the outlet-side temperature sensor 30B) is defined as the superheat degree ΔT of the refrigerant at the refrigerant outlet of the cooler 21. The opening degree of the electronic expansion valve 27 is controlled by feedback control (more specifically, PID (Proportional-Integral-Differential) control) so that the superheat degree ΔT is within a preset constant value or range. The opening degree of the electronic expansion valve 27 is variable in the range from 0 (off) to a maximum value (e.g., 500) according to the superheat degree ΔT.

[0044] In this embodiment, an accumulator 23 is provided to prevent liquid refrigerant that was not vaporized in the cooler 21 from returning to the compressor 24, and a dryer 26 is provided to remove moisture mixed in with the refrigerant liquid.

[0045] As shown in Figure 9, the control unit 60 is electrically connected to various devices and controls them. The control unit 60 is, for example, a control board including a microcontroller, and may also be equipped with a memory unit and a timing unit. The control unit 60 performs cooling operation by controlling the compressor 24, condenser fan 28, internal fan 31, and electronic expansion valve 27 based on a control program. The electronic expansion valve 27 and internal fan 31 are controlled individually for each corresponding cooler 21. For example, if the temperature of the storage chamber 13 is sufficiently higher than the set temperature, all electronic expansion valves 27 may be turned on simultaneously and all internal fans 31 may be operated simultaneously in order to perform cooling operation using all coolers 21. On the other hand, if the temperature of the storage chamber 13 is slightly lower than the set temperature, for example, only the corresponding electronic expansion valve 27 and internal fan 31 may be operated in order to perform cooling operation using one cooler 21.

[0046] Furthermore, the control unit 60 performs a defrosting operation at predetermined cooling operation intervals (for example, every 6 hours) to melt the frost that has accumulated on the cooler 21 during the cooling operation. The control unit 60 performs the defrosting operation by controlling the compressor 24, condenser fan 28, internal fan 31, electronic expansion valve 27, and heater 32 based on a control program.

[0047] In defrosting operation, the control unit 60 does not operate all three heaters 32 simultaneously, but operates only one or two heaters 32 at a time. In this embodiment, the three coolers 21 are defrosted one by one by operating the three heaters 32 sequentially. More specifically, the heater 32 for the left cooler 21L is operated, then two hours later the heater 32 for the central cooler 21M is operated, then two hours later the heater 32 for the right cooler 21R is operated, and then two hours later the heater 32 for the right cooler 21R is operated, thus defrosting the left cooler 21L, the central cooler 21M, and the right cooler 21R in that order. In this embodiment, the right portion of the storage chamber 13 where the right cooler 21R is located is recessed only by the machine room 16, as shown in Figure 3, and has a small capacity. Therefore, since the amount of frost on the right-hand cooler 21R is expected to be less than that on the other coolers 21M and 21L, the defrosting order for the right-hand cooler 21R is set to last.

[0048] During defrosting, the control unit 60 turns on the electronic expansion valve 27 connected to the cooler 21 that has a heater 32 that is currently stopped (i.e., the cooler 21 that is not being defrosted), while turning off the other electronic expansion valves 27. The control unit 60 also operates the compressor 24 and the condenser fan 28 to circulate refrigerant through the refrigeration circuit 20 and supplies refrigerant to the cooler 21 connected to the turned-on electronic expansion valve 27. Furthermore, the control unit 60 operates the internal fan 31 for the cooler 21 that is being supplied with refrigerant, while not operating the other internal fans 31.

[0049] In this way, by not operating all three heaters 32 simultaneously and cooling the storage chamber 13 with the cooler 21 that houses the heaters 32 that are not in operation, excessive temperature rise in the storage chamber 13 during defrosting can be suppressed. Furthermore, by using an electronic expansion valve 27 to supply refrigerant to the cooler 21 that houses the heaters 32 that are not in operation, the electronic expansion valve 27 alone can perform the roles of a capillary or thermostatic expansion valve (reducing the pressure of the refrigerant from the condenser 25) and a solenoid valve (turning the supply of refrigerant to the cooler 21 on and off). This suppresses the increase in the number of parts and installation space that would be required if multiple coolers 21 were provided.

[0050] Furthermore, even when three coolers 21 are arranged adjacent to each other and each cooler 21 is provided with an internal fan 31, the shielding member 38 ensures that the flow paths of each cooler 21 are reliably separated. As a result, when performing defrosting, even if the internal fan 31 for the cooler 21 connected to the electronic expansion valve 27 that is ON (i.e., generating cold air) is activated, while the internal fan 31 for the cooler 21 connected to the electronic expansion valve 27 that is OFF (i.e., defrosting) is stopped, the mixing of the flow paths of each cooler 21 can be suppressed.

[0051] If the shielding member 38 is not provided, the airflow paths of adjacent coolers 21 may mix, and cold air drawn in by an operating internal fan 31 adjacent to a cooler 21 undergoing defrosting may flow into it. As a result, there is a concern that the defrosting of the cooler 21 will not progress, leading to a defrosting failure. Also, there is a concern that warm air from a cooler 21 undergoing defrosting may be drawn in by an operating internal fan 31 adjacent to it and blown into the storage chamber 13. As a result, there is a concern that the temperature of the storage chamber 13 may rise. In this embodiment, however, the shielding member 38 can be provided to suppress such situations.

[0052] Furthermore, when the control unit 60 restarts the cooling operation after the defrosting operation described above, it performs a pre-cooling operation before the cooling operation. In the pre-cooling operation, the control unit 60 operates the compressor 24 and the condenser fan 28 to circulate refrigerant in the refrigeration circuit 20 and turns on the electronic expansion valve 27 to supply refrigerant to the cooler 21, while unlike the cooling operation, it does not operate the internal fan 31. As a result, in the pre-cooling operation, the cooler 21 that was heated by the defrosting operation is cooled. After the cooler 21 has cooled down after a predetermined pre-cooling time, the control unit 60 operates the internal fan 31 to restart the cooling operation. In the defrosting operation according to this embodiment, as described above, the three heaters 32 are operated one by one in sequence, so that the three coolers 21 are defrosted one by one in sequence. For this reason, the pre-cooling of the coolers 21 is also performed one by one in the order in which defrosting was performed.

[0053] Incidentally, when transitioning from pre-cooling to cooling operation in this manner, the temperature readings from the inlet-side temperature sensors 30A located at the refrigerant inlets of each cooler 21 rise sharply when the internal fan 31 is activated, and the superheating degree ΔT drops sharply, which can cause the opening of the electronic expansion valve 27 to decrease excessively. This is thought to be because warm air is present around the cooler 21 during defrosting, and even after the cooler 21 itself has cooled down through pre-cooling operation, the air around the cooler 21 has not cooled sufficiently.

[0054] When the internal fan 31 is activated and the cooling operation begins in this state, the amount of heat exchange between the cooler 21 and the air surrounding the cooler 21 increases, and the temperature of the refrigerant passing through the cooler 21 rises. This refrigerant then merges with the refrigerant from the other coolers 21 and circulates through the refrigeration circuit 20, so the effect of the rise in refrigerant temperature extends not only to the cooler 21 that was defrosting, but also to the refrigerant circulating through all the coolers 21. As a result, the measured values ​​of the temperature sensors 30A and 30B, which are located on the refrigerant inlet and outlet sides of all the coolers 21, increase.

[0055] The inventors of this application have experimentally found that the increase in the measured values ​​of such temperature sensors 30A and 30B tends to be larger and more pronounced in the inlet-side temperature sensor 30A than in the outlet-side temperature sensor 30B. Therefore, even if the internal fan 31 is activated and the cooling operation is initiated, there is a concern that the degree of superheating ΔT may drop sharply, causing the opening of the electronic expansion valve 27 to become excessively small, resulting in insufficient supply of refrigerant to the cooler 21.

[0056] Therefore, in this embodiment, when the internal fan 31 is activated to transition from pre-cooling to cooling, the control unit 60 sets (resets) the opening degree of all electronic expansion valves 27 to a constant value (for example, 200). The control unit 60 then maintains the opening degree of all electronic expansion valves 27 at this constant value for a predetermined time (a fixed period), and after the predetermined time has elapsed, it controls the opening degree of the electronic expansion valves 27 according to the superheating degree ΔT, similar to the normal cooling operation described above.

[0057] In this way, when the internal fan 31 is activated during the transition from pre-cooling to cooling, the opening of all electronic expansion valves 27 becomes excessively small, which can prevent a situation in which sufficient refrigerant is supplied.

[0058] If, for example, corrections such as moving averages are applied to the measured values ​​of temperature sensors 30A and 30B to suppress the effect of a sudden rise in the measured values, there is a concern that the opening control of the electronic expansion valve 27 will also be slowed down during normal cooling operation. As a result, there is a concern that excessive cooling may occur, leading to increased power consumption. In this respect, according to this embodiment, by resetting the opening of the electronic expansion valve 27 to a predetermined value, it is possible to transition smoothly from pre-cooling operation to cooling operation without adversely affecting normal cooling operation.

[0059] As previously described, the pre-cooling of the coolers 21 is performed one by one in the order in which defrosting is completed. While one cooler 21 is being pre-cooled, refrigerant is supplied to the other two coolers 21 that are not being pre-cooled, and the internal fan 31 for that cooler 21 is operating. Therefore, the timing at which the internal fan 31 operates when transitioning from the pre-cooling operation to the cooling operation is, in other words, the timing at which the internal fans 31 for all three coolers 21 are operating.

[0060] <Other Embodiments> This technology is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of this technology.

[0061] (1) The superheat sensor 30 is not limited to a configuration consisting of an inlet temperature sensor 30A located at the refrigerant inlet of the cooler 21 and an outlet temperature sensor 30B located at the refrigerant outlet of the cooler 21. For example, it may consist of an outlet temperature sensor 30B and a pressure sensor.

[0062] (2) The opening degree of the electronic expansion valve 27 is controlled by the control unit 60 according to the superheating degree ΔT, but it may also be controlled by an expansion valve control unit for the electronic expansion valve 27, which is provided separately from the control unit 60. In that case, the control unit 60 may cooperate with the expansion valve control unit to control the opening degree of the electronic expansion valve 27.

[0063] (3) This technology can also be applied to general refrigerated storage containers other than the refrigerated display case 10. A swinging door may be provided instead of a sliding door 15. [Explanation of symbols]

[0064] 10: Refrigerated display case (cooled storage), 12: Storage unit body, 13: Storage chamber, 21, 21L, 21M, 21R: Cooler, 21A: End plate, 21A1: Upper end, 24: Compressor, 25: Condenser, 27: Electronic expansion valve, 29: Refrigerant pipe, 31: Internal fan (cooler fan), 30A: Inlet temperature sensor, 30B: Outlet temperature sensor, 32: Heater (defrosting means), 33: Drain pan, 33A: Drain port (lower end), 38: Shielding member, 38A: Main surface, 60: Control unit, ΔT: Superheating degree

Claims

1. A storage facility with a storage room, Multiple coolers for cooling the storage chamber, comprising multiple coolers connected in parallel, A compressor for compressing the refrigerant from the aforementioned multiple coolers, A condenser that liquefies the refrigerant gas compressed by the compressor, A plurality of electronic expansion valves are provided between the condenser and each of the coolers, respectively, to reduce the pressure of the refrigerant from the condenser and to switch the supply of refrigerant to the coolers on and off, Each of the aforementioned coolers is provided with a plurality of defrosting means for melting frost that has accumulated on the cooler during cooling operation, It comprises a control unit and, When the control unit operates the plurality of defrosting means to perform a defrosting operation, While operating the aforementioned compressor, Instead of operating all of the aforementioned defrosting means simultaneously, one or more of the aforementioned defrosting means are operated. A cooling storage facility that turns on the electronic expansion valve connected to the cooler equipped with the defrosting means while the other electronic expansion valves are turned off.

2. The cooling storage unit according to claim 1, wherein the control unit operates the plurality of defrosting means one by one in sequence when performing the defrosting operation.

3. Each of the coolers is provided with a plurality of cooler fans that circulate the air in the storage chamber by drawing air from the storage chamber, passing it through the inside of the cooler, and blowing out the air that has passed through the cooler. When the control unit performs the defrosting operation, it activates the cooler fan for the cooler connected to the electronic expansion valve, which is ON, while stopping the cooler fan for the cooler connected to the electronic expansion valve, which is OFF. The aforementioned multiple coolers are arranged adjacent to each other. A cooling storage unit according to claim 1 or 2, wherein a shielding member for separating the flow paths of each cooling unit is provided between adjacent cooling units.

4. The aforementioned cooler is a fin-tube type heat exchanger, Below the cooler, a drain pan is provided to receive the defrost water generated when the frost on the cooler melts. The cooling storage cabinet according to claim 3, wherein the shielding member has a main surface that is sized to cover from the side from the upper end of the end plate of the cooler to the lower end of the drain pan.

5. Each of the coolers is provided with a plurality of cooler fans that circulate the air in the storage chamber by drawing air from the storage chamber, passing it through the inside of the cooler, and blowing out the air that has passed through the cooler. The opening degree of the plurality of electronic expansion valves is variable within a predetermined range. The control unit, After stopping all of the aforementioned defrosting means and ending the defrosting operation, a pre-cooling operation is performed to cool the cooler connected to the on-enabled electronic expansion valve by turning on the compressor and one or more of the aforementioned electronic expansion valves, without operating all of the aforementioned cooler fans. After the pre-cooling operation, the cooling operation is restarted by activating the multiple cooler fans and turning on the compressor and the multiple electronic expansion valves. The cooling storage unit according to claim 1 or 2, wherein when operating the multiple cooler fans in transition from the pre-cooling operation to the cooling operation, the opening degree of all of the multiple electronic expansion valves is set to a constant value for a predetermined time.

6. The cooling storage unit according to claim 5, wherein the control unit controls the opening degree of the electronic expansion valve after the predetermined time has elapsed according to the degree of superheating of the refrigerant at the refrigerant outlet of the cooler.

7. An inlet-side temperature sensor is placed in the refrigerant pipe at the refrigerant inlet of the aforementioned cooler, The cooler comprises an outlet-side temperature sensor located in the refrigerant pipe at the refrigerant outlet, The cooling storage unit according to claim 6, wherein the degree of overheating is the difference obtained by subtracting the measurement value of the inlet-side temperature sensor from the measurement value of the outlet-side temperature sensor.

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