JP2005315495A - Refrigerating system and low-temperature showcase - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating system and a low-temperature showcase enabling the suppression of rise of a construction cost and the effective energy-saving operation of a refrigerator even if they are applied to an existing system. <P>SOLUTION: This refrigerating system R is formed by distributedly feeding a refrigerant from the refrigerator 11 to coolers 46 and 48 installed in a plurality of low-temperature showcases 1A, ... and 1B, ... with different in-chamber cooling temperatures. The refrigerating system comprises a temperature type expansion valve 16 connected to the inlet of the cooler 46 of the low-temperature-showcase 1A with higher in-chamber cooling temperature and the cooler 46 connected to the inlet, a solenoid valve 14 controlling the supply of the refrigerant to the cooler 46, and an electronic expansion valve 20 connected to the inlet of the cooler 46 of the low-temperature showcase 1B with lower in-chamber cooling temperature and capable of controlling a valve opening between full close and full open. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration system including a low temperature showcase for food storage and display, a commercial refrigerator, a freezer and the like installed in a supermarket, for example, and a low temperature showcase including a plurality of coolers. .

  Conventionally, there are several to tens of low-temperature showcases for food storage and display installed in supermarkets and the like depending on the scale of the store. Such a low-temperature showcase is intended to preserve food by lowering the air temperature in the cabinet from the ambient air temperature by circulating the air cooled by heat exchange with the refrigerant in the cabinet, which is the target. The set temperature varies depending on the target food.

  That is, when the food to be displayed is a fresh food such as meat or fish, the ice temperature is, for example, −3 ° C. to 0 ° C. (−1 ° C.), and when the food is a dairy product, for example, + 3 ° C. to + 6 ° C. (+ 5 ° C.) is the set temperature.

  In addition, there are various structures of the low-temperature showcase itself, such as a multi-stage case in which a plurality of upper and lower shelves are installed, and a flat case in which a plurality of trays are arranged in parallel at the bottom. Therefore, these various types of low temperature showcases will be installed in the supermarket stores.

  Here, a conventional refrigeration system 100 will be described with reference to FIG. In this refrigeration system 100, a plurality of low-temperature showcases 102A,... And 102B,. In FIG. 5, the low temperature showcase 102A is a showcase with a set temperature of + 5 ° C. where dairy products are displayed, and the low temperature showcase 102B is a showcase with a set temperature of −1 ° C. where fresh foods are displayed.

  That is, the refrigerator 101 includes a compressor, a condenser, and the like (not shown), and a cooler (not shown) installed in each of the low-temperature showcases 102A and 102B is connected in parallel to the compressor via the refrigerant pipe 103, It constitutes the refrigeration cycle. The refrigerant pipe 103 is provided with an electromagnetic valve 104 and a temperature type expansion valve 105 for each of the low temperature showcases 102A and 102B. Depending on the store scale, there are a plurality of systems of the refrigerator 101 and a plurality of low-temperature showcases 102A and 102B. Patent Document 1 describes an example in which a plurality of low-temperature showcases or commercial refrigerators are connected to one refrigerator.

  Thereby, the supply amount of the refrigerant supplied from the refrigerator 101 is controlled by the solenoid valve 104 and the temperature type expansion valve 105 connected to each of the low temperature showcases 102A and 102B, and the insides of the low temperature showcases 102A and 102B are respectively controlled. It is cooled to a predetermined temperature.

  FIG. 6 shows a part of the refrigerant circuit when a plurality of coolers are provided in one low-temperature showcase, and in the related example, two coolers are provided. This low-temperature showcase includes two coolers, a main cooler 110 and an auxiliary cooler 111, and a temperature sensing cylinder provided on the refrigerant outlet side of each of the coolers 110 and 111. Thermal expansion valves 112 and 113 controlled by 114 and 115 are provided. Further, an electromagnetic valve 116 is provided on the upstream side of the refrigerant of the temperature type expansion valve 113 on the auxiliary cooler 111 side, and further, on the upstream side of the refrigerant of the electromagnetic valve 116 and on the main type cooler 110 side. An electromagnetic valve 117 is provided on the refrigerant upstream side of the valve 112.

Thus, the solenoid valve 117 is opened and the solenoid valve 116 is closed, so that the refrigerant flows only into the main cooler 110, and the solenoid valve 116 is duty-controlled, for example, in a state where the solenoid valve 117 is opened. Thus, the refrigerant can be allowed to flow into the auxiliary cooler 111 intermittently. Thereby, since the time until the main cooler 110 falls into the frost blockage state can be extended, the defrosting operation performed at intervals of 8 hours, for example, is performed at intervals of 14 hours.
JP-A-7-269983

  In stores handling foods, the refrigeration equipment as described above is indispensable in order to cool and retain foods. The power consumed by these devices is said to occupy approximately half of the energy used by the entire store, and there is an increasing need to reduce such electricity bills. Therefore, the energy saving operation is performed by lowering the compression ratio of the compressor of the refrigerator 101 of the refrigeration system 100 as described above. However, since the expansion valve provided for each of the low temperature showcases 102A and 102B in the conventional refrigeration system 100 is the temperature type expansion valve 105, there is a problem that it becomes difficult for the refrigerant to flow when the pressure difference between the front and rear of the valve becomes small. . For this reason, there is a problem in that sufficient refrigerant cannot be supplied to the coolers disposed in the low temperature showcases 102A and 102B, resulting in poor cooling.

  Therefore, it is conceivable to provide an electronic expansion valve having a wider control range and higher followability than the conventional temperature expansion valve 105. However, there is a demand from the market that the low temperature showcases 102 </ b> A and 102 </ b> B that have already been installed in the store use an electronic expansion valve instead of the temperature expansion valve 105 to perform an energy saving operation.

  In view of this, the temperature expansion valve 105 and the electromagnetic valve 104 of the existing refrigeration system 100 will be replaced with electronic expansion valves. Conventionally, the same refrigerator 101 has low temperature showcases 102A and 102B in different temperature zones. Are connected, the temperature-type expansion valves 105 and solenoid valves 104 of all the low-temperature showcases 102A and 102B are replaced with electronic expansion valves, or the low-temperature showcases 102A and 102B in different temperature zones are separately provided. A method of separating the refrigerant circuit and replacing only one of the temperature type expansion valve 105 and the electromagnetic valve 104 with an electronic expansion valve has been adopted.

  For this reason, there is a problem that the degree of freedom of organization of the refrigerant circuit is reduced, and there is a problem that the period and cost required for the construction are increased.

  Further, in the low temperature showcase provided with the two coolers 110 and 111 as described above, the temperature type expansion valves 112 and 113 and the electromagnetic valves 116 and 117 provided corresponding to the coolers 110 and 111 are electronically connected. By replacing the expansion valve, it is conceivable to realize an effective energy saving operation without causing a cooling failure. However, even in such a case, the temperature type expansion valves 112 and 113 and the electromagnetic valves 116 and 117 provided corresponding to both the main cooler 110 and the auxiliary cooler 111 are installed in a state where the low temperature showcase is installed in the store, respectively. Replacing with an electronic expansion valve has a problem of increasing the time and cost required for construction.

  The refrigeration system according to the first aspect of the present invention is configured by distributing and supplying refrigerant from a refrigerator to coolers provided in a plurality of low-temperature showcases having different internal cooling temperatures, and the internal cooling temperature is high. A temperature-type expansion valve connected to the cooler inlet of the lower temperature showcase, an on-off valve for controlling the supply of refrigerant to the cooler, and a cooler inlet of the lower temperature showcase with the lower internal cooling temperature And an electronic expansion valve whose valve opening degree can be controlled between fully closed and fully opened.

  A low-temperature showcase according to a second aspect of the present invention includes a main cooler and an auxiliary cooler that receives supply of the refrigerant by duty control while the refrigerant is supplied to the main cooler. An electronic expansion valve that is connected to the inlet of the heater and whose valve opening can be controlled between fully closed and fully open, a temperature-type expansion valve connected to the inlet of the auxiliary cooler, and a refrigerant supply to the auxiliary cooler are controlled And an on-off valve that performs.

  The refrigeration system of the invention of claim 3 is configured by distributing and supplying the refrigerant from the refrigerator to the coolers provided in a plurality of low-temperature showcases having different internal cooling temperatures, and the internal cooling temperature is high. A temperature-type expansion valve connected to the cooler inlet of the lower temperature showcase, an on-off valve for controlling the supply of refrigerant to the cooler, and a main cooler provided in the lower temperature showcase with the lower internal cooling temperature And while the refrigerant is being supplied to the main cooler, it is connected to the auxiliary cooler that receives supply of the refrigerant by duty control and the main cooler inlet, and the valve opening degree can be controlled between fully closed and fully opened. An electronic expansion valve, a temperature-type expansion valve connected to the auxiliary cooler inlet, and an on-off valve for controlling the supply of refrigerant to the auxiliary cooler.

  According to the refrigeration system of the first aspect of the present invention, the refrigerant is distributedly supplied from the refrigerator to the coolers provided in a plurality of low-temperature showcases having different internal cooling temperatures, and the internal cooling temperature A temperature-type expansion valve connected to the cooler inlet of the higher-temperature low-temperature showcase, an on-off valve that controls the supply of refrigerant to the cooler, and a cooler inlet of the low-temperature showcase whose inner cooling temperature is lower The electronic expansion valve is connected, and the valve opening degree can be controlled between fully closed and fully open, so the existing low temperature showcase temperature expansion valve is replaced with an electronic expansion valve to save energy. At the same time, since all are not exchanged, the construction cost and construction period can be shortened.

  Further, according to the invention, in order to replace the low temperature showcase with the lower internal cooling temperature with the electronic expansion valve, it is possible to secure the internal cooling temperature of the low temperature showcase with the lower internal cooling temperature. become able to.

  According to the low-temperature showcase of the invention of claim 2, the main cooler and an auxiliary cooler that receives supply of the refrigerant by duty control while the refrigerant is being supplied to the main cooler, An electronic expansion valve connected to the main cooler inlet, the valve opening of which can be controlled between fully closed and fully open, a temperature expansion valve connected to the auxiliary cooler inlet, and a refrigerant supply to the auxiliary cooler When switching a thermal expansion valve to an electronic expansion valve to save energy in an existing low-temperature showcase that requires no defrosting by combining a main cooler and an auxiliary cooler. Since both the temperature type expansion valves are not replaced, the construction cost and the construction period can be shortened.

  Further, according to the invention, since the main cooler is replaced with the electronic expansion valve, the internal cooling temperature can be secured.

  According to the refrigeration system of the third aspect of the present invention, the refrigerant is distributedly supplied from the refrigerator to the coolers provided in a plurality of low-temperature showcases having different internal cooling temperatures, and the internal cooling temperature A temperature-type expansion valve connected to the cooler inlet of the higher temperature low-temperature showcase, an on-off valve that controls the supply of refrigerant to the cooler, and a main unit provided in the low-temperature showcase with the lower internal cooling temperature While the refrigerant is supplied to the cooler and the main cooler, it is connected to the auxiliary cooler that receives the supply of refrigerant by duty control and the main cooler inlet, and the valve opening can be controlled between fully closed and fully open And an on-off valve for controlling the supply of refrigerant to the auxiliary cooler, and an existing low-temperature showcase for energy saving. Replaces the temperature expansion valve with an electronic expansion valve It does not replace all even when it is possible to shorten the construction cost and construction period.

  Moreover, since the electronic expansion valve is replaced with the main cooler in the low-temperature showcase with the lower internal cooling temperature, the internal cooling temperature of the low-temperature showcase with the lower internal cooling temperature can be secured. become able to.

  The present invention has been made to solve the conventional technical problems, and can suppress an increase in construction cost even when applied to an existing system, and can also save energy in a refrigerator. A refrigeration system and a low-temperature showcase that can be effectively performed are provided. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal side view of a low-temperature showcase 1 to which the present invention is applied, FIG. 2 is a diagram illustrating a piping configuration in a supermarket store where the low-temperature showcase 1 is installed, and FIG. 3 is a partial refrigerant of the low-temperature showcase 1 It is a circuit diagram.

  The low-temperature showcase 1 of the embodiment is a vertical open showcase, and includes a heat insulating wall 32 having a substantially U-shaped cross section and side plates 33 attached to both sides of the heat insulating wall 32 at the installation site. An outer layer partition plate 34 and an inner layer partition plate 36 are attached to the inner side of the heat insulating wall 32 with a space therebetween, and the space between the heat insulating wall 32 and the outer layer partition plate 34 is between the outer layer duct 37 and the inner and outer layer partition plates 36, 34. Is an inner layer duct 38, and an inner side of the inner layer partition plate 36 is a storage chamber 39.

  A plurality of shelves 41 are built in the storage chamber 39, and fluorescent lamps 40 are attached to the front of the lower surface of each shelf 41, the ceiling of the storage chamber 39, and the basket 47. It has been. A deck pan 42 is attached to the bottom of the storage chamber 39, and the bottom of the deck pan 42 is a bottom duct 43 communicating with both the ducts 37 and 38. A fan case 44 containing a blower 45 is installed in the bottom duct 43. In addition, a cooler 46 (which is a main cooler in the low-temperature showcase 1B described later) 46 is provided vertically at a lower portion in the inner layer duct 38 located behind the storage chamber 39. In the low-temperature showcase 1B, which will be described later, the cooler 46 serves as a main cooler for controlling the product temperature by suppressing adhesion of frost and reducing the number of defrosting operations. It is assumed that the auxiliary cooler 48 is vertically installed in the lower duct 38 and the auxiliary cooler 48 is positioned above the main cooler 46 and vertically installed in the inner layer duct 38.

  At the upper edge of the front opening 51 of the storage chamber 39, an outer layer discharge port 52 and an inner layer discharge port 53 are juxtaposed in the front-rear direction, the outer layer discharge port 52 being the outer layer duct 37 and the inner layer discharge port 53 being the inner layer duct 38, respectively. Communicate. A suction port 54 is formed at the lower edge of the opening 51 and communicates with the bottom duct 43.

  When the blower 45 in the fan case 44 is operated, the air in the bottom duct 43 is blown out toward the rear inner and outer layer ducts 37 and 38, and is blown up as it is in the outer layer duct 37 and the inner layer duct 38. Are blown up after heat exchange with the cooler 46, or the main cooler 46 and the auxiliary cooler 48, from the inner and outer layer discharge ports 52 and 53 on the upper edge of the opening 51 toward the suction port 54 on the lower edge, respectively. Blown out.

  As a result, an inner cool air curtain and an outer air curtain protecting the inner cool air curtain are formed in the opening 51 of the storage chamber 39, and the intrusion of outside air from the opening 51 is prevented or suppressed. A part of the cool air curtain is circulated in the storage chamber 39 to cool the storage chamber 39.

  These cold air and the like return from the suction port 54 to the bottom duct 43 and are sucked into the blower 45 again. Further, a defrost heater 67 is attached to the cooler (main cooler) 46, and heat is generated to melt frost on the cooler (main cooler) 46. In the low-temperature showcase 1B described later, a defrost heater 68 is attached to the auxiliary cooler 48, and heat is generated to melt frost formation on the auxiliary cooler 48. In the figure, reference numeral 63 denotes a control temperature sensor provided in the inner layer duct 38, which is connected to the control device 64 (only FIG. 2 is shown).

  Next, the refrigeration system R of the present invention will be described with reference to FIG. In FIG. 2, reference numeral 1A... Denotes a low temperature showcase (dairy product refrigeration case) for storing and displaying dairy products (commodities). Also, 1B... Is a low temperature showcase (fresh temperature ice temperature case) for storing and displaying fresh fish (commodities). For example, three units are arranged in parallel. Each of the low temperature showcases 1A and 1B has the same configuration as the low temperature showcase 1 described above.

  Each of the low-temperature showcases 1A, 1B, 1B, is installed along the wall of a supermarket store. On the other hand, 11 is a stand-alone refrigerator installed (separately installed) in a machine room (not shown) configured outside the store. Thereby, the refrigerating system R of the present invention is constituted by the refrigerator 11 and the low-temperature showcases 1A, 1B,.

  The refrigerator 11 is composed of a compressor and a condenser (not shown), and the inlet side of the cooler 46 of the low-temperature showcase 1A (refrigerated case) is an electromagnetic that controls the supply of refrigerant to the cooler 46, respectively. It is connected in parallel to the liquid refrigerant pipe 17 of the refrigerator 11 via the valve (open / close valve) 14 and the temperature type expansion valve 16, and the outlet side of the cooler 46... Is parallel to the gas refrigerant pipe 18 of the refrigerator 11. Connected. The temperature type expansion valve 16 operates based on a temperature sensing cylinder (not shown) provided on the outlet side of the coolers 46.

  On the other hand, the low temperature showcase 1B (ice temperature case)... Is equipped with two coolers, the main cooler 46 and the auxiliary cooler 48, as described above, and is shown in the partial refrigerant circuit diagram of FIG. As described above, the inlet side of the main coolers 46... Is connected in parallel to the liquid refrigerant pipe 17 of the refrigerator 11 via the electronic expansion valve 20, and the outlet side of the main coolers 46. The gas refrigerant pipe 18 is connected in parallel. The electronic expansion valve 20 has a fully closed function, and the valve opening degree is controlled between fully closed and fully open based on the control device 64 to which the control temperature sensor 63 is connected as described above. . Further, the inlet side of the auxiliary coolers 48... Is connected to the electronic expansion valve 20 and the main cooler 46 via an electromagnetic valve (open / close valve) 21 and a temperature type expansion valve 22 for controlling the refrigerant supply to the auxiliary cooler 48, respectively. On the other hand, they are connected in parallel to the liquid refrigerant pipe 17 of the refrigerator 11 so as to be connected in parallel. Further, the outlet side of the auxiliary coolers 48 is connected in parallel to the gas refrigerant pipe 18 of the refrigerator 11. The temperature type expansion valve 22 is operated based on a temperature sensing cylinder 23 provided on the outlet side of the auxiliary coolers 48.

  The control device 64 of the low-temperature showcase 1B and the control device (not shown) of the low-temperature showcase 1A are constituted by a general-purpose microcomputer, and a control temperature setting switch (not shown) and a fluorescent lamp are provided on the input side of the microcomputer. Forty lighting switches (not shown) are connected. Further, the output of a defrosting return temperature sensor (not shown) for detecting the defrosting return temperature of the cooler (main cooler) 46 and the auxiliary cooler 48 is connected, and the temperature of the air discharged from the inner layer duct 38 (discharge) The output of the control temperature sensor 63 for detecting the air temperature) is input. Further, the electromagnetic valve 14 or the electronic expansion valve 20 and defrosting heaters 67 and 68 provided in the coolers 46 and 48 are connected to the output side of the microcomputer.

  Furthermore, the control apparatus provided in each low temperature showcase 1A and 1B is connected to the centralized management apparatus (not shown) installed in the store via the communication line. This centralized management device is composed of, for example, a personal computer, and the control devices for the low temperature showcases 1A, 1B,... Installed in the store and the control device (not shown) of the refrigerator 11 are connected via communication lines. It is connected.

  Operation will be described with the above configuration. When the compressor of the refrigerator 11 is operated, the refrigerant is depressurized by the temperature expansion valve 16 or the electronic expansion valve 20 through the liquid refrigerant pipe 17, and then the low temperature showcases 1A, 1B,. It is supplied to a cooler (main cooler) 46 where it evaporates. At this time, the air (cold air) heat-exchanged with the cooler (main cooler) 46 rises in the inner layer duct 38 and is discharged from the inner layer discharge port 53 as described above.

  Here, if the set value of the temperature of the air discharged from the inner layer outlet 53 of the low temperature showcase 1A (refrigerated case) (discharged air temperature) is set to + 5 ° C. by the control temperature setting switch, the microcomputer Based on the set temperature + 5 ° C. and the discharge air temperature detected by the control temperature sensor 63, the opening / closing control of the solenoid valve 14 is performed. Moreover, the temperature type expansion valve 16 has its valve opening adjusted based on a temperature sensing cylinder provided on the refrigerant outlet side of the cooler 46. By such a cooling operation, the temperature of a commodity such as a dairy product displayed on the shelf 41 in the storage chamber 39 of the low temperature showcase 1A is maintained at about + 5 ° C.

  On the other hand, if the set value of the temperature (discharged air temperature) of the air discharged from the inner layer outlet 53 of the low temperature showcase 1B (ice temperature case) is set to -1 ° C. by the control temperature setting switch, the microcomputer Controls the opening degree of the electronic expansion valve 20 based on the set temperature −1 ° C. and the discharge air temperature detected by the control temperature sensor 63.

  Further, the control device 64 of the low temperature showcase 1B operates the electromagnetic valve 21 for a certain period of time as shown in FIG. 4 while the refrigerant is supplied to the main cooler 46, that is, while the electronic expansion valve 20 is opened. The refrigerant is supplied to the auxiliary cooler 48 by performing so-called duty control that opens for a predetermined period of time and closes for the remaining period. Thus, while the refrigerant is being supplied to the main cooler 46, the refrigerant is intermittently supplied to the auxiliary cooler 48, and the refrigerant flowing into the auxiliary cooler 48 is the refrigerant inlet side of the auxiliary cooler 48. The pressure is reduced by a temperature type expansion valve 22 provided in By such a cooling operation, the temperature of the commodity such as fresh fish displayed on the shelf 41 in the storage chamber 39 of the low temperature showcase 1B is maintained at about -1 ° C.

  Further, the microcomputer constituting the control device 64 of the low temperature showcase 1B has a clock function. For example, every 14 hours, the electronic expansion valve 20 is fully closed and the defrosting heaters 67 and 68 are energized. The defrosting heaters 67 and 68 are energized to generate heat, and the frosting of the coolers 46 and 48 is melted and removed. When the defrosting of each of the coolers 46 and 48 progresses and reaches a defrosting return temperature such as + 8 ° C., the microcomputer moves to the defrosting heaters 67 and 68 based on the output of the defrosting return temperature sensor. Stop energizing. Thereafter, after a predetermined draining time (defrost heaters 67 and 68 are OFF and electronic expansion valve 20 is fully closed), the above cooling operation is resumed.

  With the above configuration, in this embodiment, in the refrigeration system R in which the low temperature showcases 1A, 1B,... In different temperature zones are connected to the same refrigerator 11, the one with the higher cooling temperature in the refrigerator, A temperature-type expansion valve 16 is provided in the low-temperature showcase 1A, and an electronic expansion valve 20 is provided in the lower cooling temperature in the cabinet, that is, the low-temperature showcase 1B. Therefore, when the capacity control of the refrigerator 11 is performed by, for example, a low pressure switch, the evaporating temperature of each cooler 46 is increased by increasing the cut-out value of the compressor, and the cooling temperature inside the refrigerator is first of all. Although the lower temperature showcase 1B has an effect on the cooling performance, in this embodiment, as described above, the electronic expansion valve has a wider control range and higher followability on the low temperature showcase 1B side than the temperature type expansion valve. By providing 20, it becomes possible to realize energy-saving operation of the refrigerator 11 without causing poor cooling in each of the low-temperature showcases 1A and 1B.

  Further, even in the existing refrigeration system, the temperature type expansion valve and the electromagnetic valve (open / close valve) provided in the low temperature showcase 1B with the lower internal cooling temperature as in the refrigeration system R as described above are provided. By replacing the electronic expansion valve 20, energy saving can be achieved while ensuring the cooling temperatures in the cabinets of the low temperature showcases 1A, 1B, and 1B. At this time, since the temperature type expansion valves and solenoid valves of all the low temperature showcases 1A, 1B,... Are not replaced with the electronic expansion valve 20, the time required for the construction is shortened and the construction cost is reduced. Will be able to.

  In particular, in this embodiment, the cooler showcase 1B having the lower internal temperature is provided with two coolers, that is, a main cooler 46 and an auxiliary cooler 48, and frost is attached to each cooler 46, By dispersing in 48, the defrosting interval is prevented by suppressing or suppressing frost blockage, for example, one cooler that is performed at 8 hour intervals is performed at 14 hour intervals, and as a result, the defrosting frequency is reduced. And effective temperature management. In such a case, an electronic expansion valve having a wider control range and higher followability than the temperature type expansion valve only in the cooler having the smaller difference between the evaporation temperature of the low temperature showcase 1B and the internal temperature, that is, the main cooler 46. By providing 20, the energy saving operation of the refrigerator 11 can be realized without causing poor cooling of the low temperature showcase 1B.

  Therefore, even in such a case, even in the existing low temperature showcase 1B having two coolers, the temperature type expansion valve and the electromagnetic provided on the main cooler 46 side as in the low temperature showcase 1B as described above are used. By replacing the valve (open / close valve) with the electronic expansion valve 20, energy saving can be achieved while ensuring the cooling temperature in the cabinet of the low temperature showcase 1B. At this time, not all the temperature-type expansion valves and solenoid valves provided in the low-temperature showcase 1B are replaced with the electronic expansion valve 20, so that the time required for construction can be shortened and the construction cost can be reduced. Become.

  In the refrigeration system R in the above embodiment, two coolers are provided in the low-temperature showcase having the lower internal cooling temperature, that is, the low-temperature showcase 1B (ice temperature case), and the main cooling is performed as described above. Although the electronic expansion valve 20 is provided only on the side of the cooler 46, the low temperature showcase 1B may include only one cooler and the electronic expansion valve 20 may be provided on the cooler. To do.

It is a vertical side view of the low-temperature showcase to which this invention is applied. It is a figure explaining the piping structure in the store of the supermarket where the low temperature showcase was installed. It is a partial refrigerant circuit diagram of a low-temperature showcase. It is a figure explaining control of an electronic expansion valve and a solenoid valve. It is a figure explaining the piping structure of the conventional refrigeration system. It is a partial refrigerant circuit diagram of the conventional low-temperature showcase.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low temperature showcase 1A Refrigeration case for dairy products 1B Ice temperature case for fresh fish 11 Refrigerator 14 Electromagnetic valve 16 Thermal expansion valve 39 Storage room 46 Cooler (main cooler)
48 Auxiliary cooler 63 Control temperature sensor 64 Control device 67, 68 Defrost heater

Claims (3)

In a refrigeration system that distributes and supplies refrigerant from a refrigerator to coolers provided in a plurality of low-temperature showcases with different internal cooling temperatures,
A temperature-type expansion valve connected to the cooler inlet of the low-temperature showcase having the higher internal cooling temperature, and an on-off valve for controlling the supply of refrigerant to the cooler;
A refrigeration system comprising an electronic expansion valve connected to a cooler inlet of the low-temperature showcase having a lower internal cooling temperature and capable of controlling a valve opening degree between fully closed and fully opened . In a low-temperature showcase comprising a main cooler and an auxiliary cooler that receives supply of the refrigerant by duty control while the refrigerant is being supplied to the main cooler,
An electronic expansion valve connected to the main cooler inlet, the valve opening degree being controllable between fully closed and fully open;
A low-temperature showcase comprising a temperature type expansion valve connected to the auxiliary cooler inlet and an on-off valve for controlling the supply of refrigerant to the auxiliary cooler. In a refrigeration system that distributes and supplies refrigerant from a refrigerator to coolers provided in a plurality of low-temperature showcases with different internal cooling temperatures,
A temperature-type expansion valve connected to the cooler inlet of the low-temperature showcase having the higher internal cooling temperature, and an on-off valve for controlling the supply of refrigerant to the cooler;
A main cooler provided in the low-temperature showcase having a lower internal cooling temperature, and an auxiliary cooler that receives supply of refrigerant by duty control while the refrigerant is being supplied to the main cooler;
An electronic expansion valve connected to the main cooler inlet, the valve opening degree being controllable between fully closed and fully open;
A refrigeration system comprising: a temperature type expansion valve connected to the auxiliary cooler inlet; and an on-off valve that controls supply of refrigerant to the auxiliary cooler.

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