showcase

Abstract

To reduce energy consumption while suppressing increases in manufacturing costs, thereby achieving energy conservation. [Solution] A showcase 1 comprising a storage chamber 14 defined inside the case body 10, a blower fan 19 that circulates air between the storage chamber 14 and a ventilation passage 15, an evaporator 18 that cools the air passing through the ventilation passage 15 by the blower fan 19, a temperature control sensor S1 that detects the temperature of the air blown out from the ventilation passage 15 into the storage chamber 14 as the temperature control temperature, and a control unit 30 that drives a refrigerant supply device 20 when the temperature control temperature is equal to or higher than the cooling start temperature, and drives off the refrigerant supply device 20 when the temperature control temperature is equal to or lower than the cooling stop temperature, wherein the showcase 1 comprises an internal temperature sensor S2 that detects the temperature of the storage chamber 14 as the internal temperature, and the control unit 30 performs a shift operation to raise the value of the cooling stop temperature, provided that the value of the internal temperature detected by the internal temperature sensor S2 is equal to or lower than a reference value.

Description

Technical Field

[0001] The present invention relates to a showcase.

Background Art

[0002] Conventionally, a showcase has been proposed in Patent Document 1 for cooling products placed on a product placement shelf provided in a storage room with multiple levels along the vertical direction. In this showcase, the refrigerant flow to the evaporator is adjusted according to the detection result of a temperature control sensor that detects the temperature of the air cooled by the evaporator and blown into the storage room, and the internal air of the storage room is cooled to a predetermined temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above-mentioned showcase, in the intermediate period except summer and winter, the installation temperature and humidity may significantly decrease due to the influence of leakage of cold air, etc., and the cooling load may decrease. However, in the above showcase, the refrigerant flow is adjusted according to the detection result of the temperature control sensor regardless of the magnitude of the cooling load, so the internal air of the storage room is cooled more than necessary, and as a result, power etc. may be wasted.

[0005] Therefore, it is conceivable to install an external temperature sensor to detect the ambient temperature around the showcase and determine the magnitude of the cooling load based on the sensor's readings. However, showcases have the characteristic that the cooling load changes depending on the temperature and arrangement of the products in the storage compartment, making it undesirable to determine the magnitude of the cooling load based on the ambient temperature. Moreover, the installation of an external temperature sensor would lead to an increase in manufacturing costs due to an increase in the number of parts, which is undesirable.

[0006] In view of the above circumstances, the present invention aims to provide a showcase that can reduce power consumption and achieve energy savings while suppressing an increase in manufacturing costs. [Means for solving the problem]

[0007] To achieve the above objective, the showcase according to the present invention comprises: a storage chamber defined inside the case body and having multiple product display shelves arranged vertically; an air circulation means for circulating air between the storage chamber and a ventilation passage outside the storage chamber; a cooling means for cooling the air passing through the ventilation passage by the air circulation means; a temperature control sensor for detecting the temperature of the air blown out from the ventilation passage into the storage chamber as a temperature control temperature; and a control unit that starts cooling by the cooling means when the temperature control temperature detected by the temperature control sensor is equal to or higher than the cooling start temperature, and stops cooling by the cooling means when the temperature control temperature is lower than or equal to the cooling stop temperature, which is lower than the cooling start temperature, and the showcase maintains products placed on the product display shelves in a desired cooling state, further comprising: an internal temperature sensor installed inside the storage chamber and detecting the temperature of the storage chamber as the internal temperature, wherein the control unit performs a shift operation to raise the value of the cooling stop temperature, provided that the value of the internal temperature detected by the internal temperature sensor is equal to or lower than a predetermined reference value.

[0008] Furthermore, the present invention is characterized in that, in the above-mentioned showcase, the control unit performs the shift operation when the internal temperature value is below the reference value for a predetermined number of consecutive times.

[0009] Furthermore, the present invention is characterized in that, in the above-mentioned showcase, the control unit increases the value of the cooling start temperature when performing the shift operation.

[0010] Furthermore, the present invention is characterized in that, in the above-mentioned showcase, the control unit raises the values ​​of the cooling stop temperature and the cooling start temperature by a predetermined value when performing the shift operation.

[0011] Furthermore, the present invention is characterized in that, in the above-mentioned showcase, the control unit restricts the next shift operation until a predetermined restriction time has elapsed after the shift operation has been performed.

[0012] Furthermore, in the above-mentioned showcase, the control unit is characterized in that, when the internal temperature value detected by the internal temperature sensor becomes higher than or equal to a release value which is higher than the reference value, it performs a shift release operation to return the cooling stop temperature and the cooling start temperature to their initial values.

[0013] Furthermore, the present invention is characterized in that, in the above-mentioned showcase, the control unit restricts the shift operation from the start of the defrosting operation until a predetermined waiting time has elapsed after the completion of the defrosting operation when a defrosting operation is performed to remove frost adhering to the evaporator constituting the cooling means. [Effects of the Invention]

[0014] According to the present invention, an internal temperature sensor installed inside the storage chamber detects the temperature of the storage chamber as the internal temperature, and the control unit performs a shift operation to raise the cooling stop temperature value, provided that the value of the internal temperature detected by the internal temperature sensor falls below a predetermined reference value. This has the effect of reducing power consumption and saving energy while suppressing an increase in manufacturing costs. [Brief explanation of the drawing]

[0015] [Figure 1]FIG. 1 is a cross-sectional side view schematically showing the internal structure of a showcase according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a characteristic control system of a showcase according to an embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart showing the processing contents of the cooling control process performed by the control unit shown in FIG. 2. [Figure 4] FIG. 4 is a flowchart showing the processing contents of the temperature setting process performed by the control unit shown in FIG. 2.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a showcase according to the present invention will be described in detail.

[0017] FIGS. 1 and 2 each show a showcase according to an embodiment of the present invention. FIG. 1 is a cross-sectional side view schematically showing the internal structure, and FIG. 2 is a block diagram showing a characteristic control system.

[0018] The showcase 1 illustrated here is for accommodating products in stores such as supermarkets and convenience stores, and is configured to include a case body 10, a temperature control sensor S1, an internal temperature sensor S2, and a control unit 30.

[0019] The case body 10 includes a bottom surface portion 11, a rear surface portion 12, and a top surface portion 13, and a storage chamber 14 with an open front is formed in a portion surrounded by these bottom surface portion 11, rear surface portion 12, and top surface portion 13. Further, a ventilation passage 15 is provided in the case body 10 in a manner partitioned from the storage chamber 14.

[0020] The ventilation passage 15 is formed inside the bottom surface portion 11, rear surface portion 12, and top surface portion 13, and includes a lower duct 15a, a rear duct 15b, and an upper duct 15c.

[0021] The lower duct 15a is formed in a portion of the bottom surface portion 11 that is below the bottom plate 11a that constitutes the bottom surface of the storage chamber 14. A suction port 16 extending along the left - right direction is formed at the front end portion of the bottom plate 11a. That is, the suction port 16 is an opening formed in the lower front part of the storage chamber 14.

[0022] The rear duct 15b is formed in a portion of the rear surface portion 12 that is behind the back plate 12a that constitutes the back surface of the storage chamber 14. The lower end portion of this rear duct 15b communicates with the rear end portion of the lower duct 15a.

[0023] The upper duct 15c is formed in a portion of the top surface portion 13 that is above the top plate 13a that constitutes the top surface of the storage chamber 14. The rear end portion of this upper duct 15c communicates with the upper end portion of the rear duct 15b. A blow - out port 17 extending along the left - right direction is formed at the front end portion of the top plate 13a. That is, the blow - out port 17 is an opening formed in the upper front part of the storage chamber 14.

[0024] An evaporator 18 and a blower fan 19 are installed inside the ventilation path 15. The evaporator 18 constitutes a refrigerant circuit that circulates refrigerant with a refrigerant supply device 20. Here, the refrigerant supply device 20 is configured to include a compressor, a condenser, and an expansion mechanism. When this refrigerant supply device 20 is driven, it sucks refrigerant from the evaporator 18, compresses the refrigerant with the compressor, condenses the refrigerant in the condenser, and adiabatically expands it with the expansion mechanism and sends it to the evaporator.

[0025] Thereby, the evaporator 18 is a cooling means that performs heat exchange between the refrigerant passing through itself and the air passing through the ventilation path 15, and cools the air by the evaporation of the refrigerant.

[0026] When the blower fan 19 is driven, it sends the air sucked into the ventilation path 15 through the suction port 16 to the blow - out port 17, and blows it out from the blow - out port 17 into the storage chamber 14, thereby circulating air between the storage chamber 14 and the ventilation path 15.

[0027] In the storage chamber 14, a plurality of shelves 21 for placing products are provided along the vertical direction. The product placement shelves 21 are of a conventionally well-known type and are for placing products.

[0028] In such a showcase 1, when the refrigerant supply device 20 and the blower fan 19 are driven, the air that has passed through the evaporator 18 is circulated and supplied to the storage chamber 14 through the ventilation passage 15. By cooling the internal air of the storage chamber 14, the products placed on the product placement shelves 21 are maintained at a desired cooling temperature.

[0029] The temperature control sensor S1 is disposed at a location where the air cooled by the evaporator 18 in the ventilation passage 15 passes through. This temperature control sensor S1 periodically detects the temperature of the air blown from the ventilation passage 15 into the storage chamber 14 as the temperature control temperature, and sends the detection result to the control unit 30 as the temperature control temperature.

[0030] The internal temperature sensor S2 is disposed inside the storage chamber 14, more specifically, at a location near the top plate 13a in the storage chamber 14. This internal temperature sensor S2 periodically detects the temperature of the storage chamber 14 as the internal temperature, and sends the detection result to the control unit 30 as the internal temperature.

[0031] The control unit 30 is connected to the blower fan 19, the refrigerant supply device 20, the temperature control sensor S1, and the internal temperature sensor S2, and comprehensively controls the operation of the showcase 1 according to the programs and data stored in the similarly connected storage unit 31. Such a control unit 30 includes a cooling control unit 30a and a temperature setting processing unit 30b.

[0032] The cooling control unit 30a performs the cooling control process described later. This cooling control unit 30a controls the driving of the refrigerant supply device 20 and the like by comparing the current value of the temperature control temperature detected by the temperature control sensor S1 with the cooling stop temperature T1 or the cooling start temperature T2 (T1 < T2) included in the temperature information 31a stored in the storage unit 31.

[0033] The temperature setting processing unit 30b performs the temperature setting process described later. This temperature setting processing unit 30b compares the current internal temperature detected by the internal temperature sensor S2 with a reference value (for example, about 4°C) included in the temperature information 31a, and if the current internal temperature is less than or equal to the reference value, it performs a shift operation to raise the cooling stop temperature T1 and the cooling start temperature T2 by a predetermined value (for example, 1 to 2°C), provided that certain conditions are met. Here, the reference value is a threshold value for determining that the cooling load of the storage chamber 14 is small.

[0034] Furthermore, the temperature setting processing unit 30b compares the current internal temperature detected by the internal temperature sensor S2 with the release value (for example, about 7°C) included in the temperature information 31a, and if the current internal temperature is greater than or equal to the release value, it performs a shift release operation to return the cooling stop temperature T1 and the cooling start temperature T2 to their initial values. Here, the release value is a value greater than the reference value and is a threshold for determining that the cooling load of the storage chamber 14 is high.

[0035] Furthermore, the control unit 30 may be implemented, for example, by causing a processing unit such as a CPU (Central Processing Unit) to execute a program, i.e., by software; by hardware such as an IC (Integrated Circuit); or by using a combination of software and hardware.

[0036] Figure 3 is a flowchart showing the processing details of the cooling control process performed by the control unit 30 shown in Figure 2.

[0037] In this cooling control process, the cooling control unit 30a of the control unit 30 determines whether or not the refrigerant supply device 20 is running (step S101).

[0038] If the refrigerant supply device 20 is running (step S101: Yes), the cooling control unit 30a determines whether the current temperature of the temperature control sensor S1 is less than or equal to the cooling stop temperature T1 in the temperature information 31a read from the storage unit 31 (step S102).

[0039] If the temperature control temperature exceeds the cooling stop temperature T1 (step S102: No), the cooling control unit 30a maintains the operation of the refrigerant supply device 20 (step S103), and then returns to the previous step to terminate the current process. As a result, the temperature of the air inside the storage chamber 14 gradually decreases.

[0040] On the other hand, if the temperature control temperature is below the cooling stop temperature T1 (step S102: Yes), the cooling control unit 30a stops the refrigerant supply device 20 (step S104), and then returns to the previous step to end the current process. As a result, the temperature of the air inside the storage chamber 14 gradually increases.

[0041] By the way, if the refrigerant supply device 20 is stopped (step S101: No), the cooling control unit 30a determines whether the current temperature of the temperature control sensor S1 is equal to or greater than the cooling start temperature T2 in the temperature information 31a read from the storage unit 31 (step S105).

[0042] If the temperature control temperature falls below the cooling start temperature T2 (step S105: No), the cooling control unit 30a maintains the deactivation of the refrigerant supply device 20 (step S106), and then returns to the previous step to terminate the current process. As a result, the temperature of the air inside the storage chamber 14 gradually increases.

[0043] On the other hand, if the temperature control temperature is above the cooling start temperature T2 (step S105: Yes), the cooling control unit 30a drives the refrigerant supply device 20 (step S107), and then returns to the previous step to end the current process. As a result, the temperature of the air inside the storage chamber 14 gradually decreases.

[0044] By implementing this cooling control process, the internal air of the storage chamber 14 can be cooled to a predetermined temperature range, thereby cooling the products placed on each product shelf 21.

[0045] During the cooling operation period in which such cooling control processing is performed, that is, the period excluding the time of defrosting operation to remove frost attached to the evaporator 18 and the time from the end of this defrosting operation until a predetermined waiting period (for example, about 30 minutes) has elapsed, the control unit 30 performs the following temperature setting processing.

[0046] Figure 4 is a flowchart showing the processing details of the temperature setting process performed by the control unit 30 shown in Figure 2.

[0047] In this temperature setting process, the temperature setting processing unit 30b of the control unit 30 determines whether the cooling stop temperature T1 and the cooling start temperature T2 included in the temperature information 31a stored in the storage unit 31 are initial values ​​(step S201).

[0048] If the cooling stop temperature T1 and the cooling start temperature T2 are at their initial values ​​(step S201: Yes), the temperature setting processing unit 30b determines whether the current internal temperature value from the internal temperature sensor S2 is less than or equal to the reference value in the temperature information 31a read from the storage unit 31 (step S202).

[0049] If the current internal temperature exceeds the reference value (step S202: No), the temperature setting processing unit 30b determines that the cooling load is within the acceptable range and terminates the process by returning to the previous step without performing the processing described later.

[0050] If the current internal temperature is below the reference value (step S202: Yes), the temperature setting processing unit 30b determines whether the number of consecutive times it has determined that the current internal temperature is below the reference value is m times (for example, 2 times) (step S203).

[0051] If the above number of consecutive times has not reached m (step S203: No), the temperature setting processing unit 30b repeats the processes of step S202 and step S203.

[0052] On the other hand, if the above-mentioned number of consecutive occurrences reaches m times (step S203: Yes), that is, if the state in which the current value of the internal temperature is below the reference value is met for a predetermined number of consecutive times, the temperature setting processing unit 30b assumes that the cooling load is small and performs a shift operation to raise the cooling stop temperature T1 and the cooling start temperature T2 by a predetermined value (for example, about 1°C) (step S204), and then returns the procedure to terminate the current process. The cooling stop temperature T1 and the cooling start temperature T2, which were raised by a predetermined value in step S204, are stored in the temperature information 31a of the storage unit 31 and used in the cooling control process described above.

[0053] By the way, if the cooling stop temperature T1 and the cooling start temperature T2 are not at their initial values ​​(step S201: No), that is, if a shift operation has already been performed and the cooling stop temperature T1 and the cooling start temperature T2 have risen above their initial values, the temperature setting processing unit 30b determines whether a preset regulated time (e.g., 20 minutes) has elapsed since the previous shift operation (step S205).

[0054] If the regulated time has not elapsed (step S205: No), the temperature setting processing unit 30b returns to the previous step and terminates the current process without performing the process described later.

[0055] If the regulated time has elapsed (Step S205: Yes), the temperature setting processing unit 30b determines whether the current internal temperature value from the internal temperature sensor S2 is less than or equal to the reference value in the temperature information 31a read from the storage unit 31 (Step S206).

[0056] If the current internal temperature is below the reference value (step S206: Yes), the temperature setting processing unit 30b determines whether the number of consecutive times it has determined that the current internal temperature is below the reference value is m times (for example, 2 times) (step S207).

[0057] If the above number of consecutive times has not reached m (step S207: No), the temperature setting processing unit 30b repeats the processes of step S206 and step S207.

[0058] On the other hand, if the above-mentioned number of consecutive times reaches m (step S207: Yes), that is, if the state in which the current value of the internal temperature is below the reference value is achieved for a predetermined number of consecutive times, the temperature setting processing unit 30b determines whether the number of times the shift operation has been performed is n (for example, about 2 times) or less (step S208). Note that the number of times the shift operation has been performed is not the cumulative number of times, but the number of times the cooling stop temperature T1 and the cooling start temperature T2 have been raised from their initial values.

[0059] If the number of shift operations exceeds n (step S208: No), the temperature setting processing unit 30b returns to the previous step and terminates the current process without performing the process described later.

[0060] If the number of shift operations performed is n or less (step S208: Yes), the temperature setting processing unit 30b performs a shift operation to raise the cooling stop temperature T1 and the cooling start temperature T2 by a predetermined value (step S209), and then returns to the previous step to terminate the current process. The cooling stop temperature T1 and the cooling start temperature T2, which were raised by a predetermined value in step S209, are stored in the temperature information 31a of the storage unit 31 and used in the cooling control process described above.

[0061] In step S206 above, if the current internal temperature exceeds the reference value (step S206: No), the temperature setting processing unit 30b determines whether the current internal temperature is equal to or greater than the release value (step S210).

[0062] If the current internal temperature is less than the release value (step S210: No), that is, if the current internal temperature is above the reference value but below the release value, the temperature setting processing unit 30b considers the cooling load to be within the acceptable range and returns to the previous step without performing the processing described later, thereby terminating the current process.

[0063] If the current internal temperature is greater than or equal to the release value (step S210: Yes), the temperature setting processing unit 30b assumes that the cooling load is high and performs a shift release operation to return the cooling stop temperature T1 and cooling start temperature T2 to their initial values ​​(step S211), and then returns to the previous step to terminate the current process.

[0064] As described above, according to the showcase 1, which is an embodiment of the present invention, the control unit 30 raises the values ​​of the cooling stop temperature T1 and the cooling start temperature T2 by predetermined values, provided that the current value of the internal temperature detected by the internal temperature sensor S2 falls below a reference value. Therefore, when the cooling load is relatively small, it is possible to suppress excessive cooling of the internal air of the storage chamber 14. Moreover, it is possible to determine the magnitude of the cooling load without requiring an external temperature sensor as in the conventional method. Consequently, it is possible to reduce power consumption and save energy while suppressing an increase in manufacturing costs.

[0065] In particular, since the cooling load is determined using the internal temperature detected by the internal temperature sensor S2 rather than the temperature control sensor S1, there are the following advantages.

[0066] The internal temperature detected by the internal temperature sensor S2 exhibits a smaller temperature change per unit time compared to the temperature control temperature detected by the temperature control sensor S1, due to the installation environment. Therefore, using the internal temperature can improve the accuracy of determining whether or not there is a cooling load.

[0067] Furthermore, according to the above showcase 1, the cooling load is determined by the current internal temperature detected by the internal temperature sensor S2. This is different from calculating the average internal temperature for each cycle to determine the cooling load, as it allows for instantaneous determination of the cooling load and enables responsive shift operation.

[0068] According to the above showcase 1, the control unit 30 performs a shift operation when the current internal temperature is below a reference value for a predetermined number of consecutive times, thereby preventing the cooling stop temperature T1, etc. from rising due to false detection of the internal temperature.

[0069] According to the above showcase 1, when the control unit 30 performs a shift operation, it restricts the next shift operation until a preset restriction time has elapsed. This allows the system to determine whether or not to perform the next shift operation while the effects of the previous shift operation are still being realized, thus avoiding situations where shift operations are performed excessively.

[0070] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made.

[0071] In the above-described embodiment, during the temperature setting process, if the current internal temperature was below a reference value, both the cooling stop temperature T1 and the cooling start temperature T2 were raised by a predetermined value. However, in the present invention, only the cooling stop temperature may be raised. Furthermore, the increase in the cooling stop temperature and the increase in the cooling start temperature may be of different magnitudes.

[0072] In the embodiment described above, the showcase 1 was equipped with a refrigerant supply device 20, but in the present invention, the compressor and condenser constituting the refrigerant supply device may be installed outside the showcase.

[0073] In the embodiment described above, the shift operation in the temperature setting process was conditional on the current internal temperature being below a reference value for a predetermined number of consecutive times (m times). However, in the present invention, such a condition is not required. [Explanation of Symbols]

[0074] 1...Showcase, 10...Case body, 14...Storage compartment, 15...Ventilation passage, 16...Intake port, 17...Outlet port, 18...Evaporator, 19...Blower fan, 20...Refrigerant supply device, 21...Product display shelf, 30...Control unit, 30a...Cooling control unit, 30b...Temperature setting processing unit, 31...Storage unit, 31a...Temperature information, S1...Temperature control sensor, S2...Second temperature sensor.

Claims

1. A storage compartment is defined inside the case body, with multiple shelves for placing products arranged vertically. An air circulation means for circulating air between the storage chamber and the ventilation passage outside the storage chamber, A cooling means for cooling the air passing through the ventilation passage by the air circulation means, A temperature control sensor that detects the temperature of the air blown out from the ventilation passage into the storage compartment as the temperature control temperature, A control unit which starts cooling by the cooling means when the temperature detected by the temperature control sensor is equal to or equal to the cooling start temperature, and stops cooling by the cooling means when the temperature detected is equal to or equal to the cooling stop temperature which is lower than the cooling start temperature. Equipped with, A showcase that maintains products placed on the aforementioned product display shelf in a desired cooling state, The storage chamber is equipped with an internal temperature sensor that is installed inside the storage chamber and detects the temperature of the storage chamber as the internal temperature, The showcase is characterized in that the control unit performs a shift operation to raise the value of the cooling stop temperature, provided that the value of the internal temperature detected by the internal temperature sensor falls below a predetermined reference value.

2. The showcase according to claim 1, characterized in that the control unit performs the shift operation when the internal temperature value is below the reference value for a predetermined number of consecutive times.

3. The showcase according to claim 2, characterized in that the control unit increases the value of the cooling start temperature when performing the shift operation.

4. The showcase according to claim 3, characterized in that the control unit raises the values ​​of the cooling stop temperature and the cooling start temperature by a predetermined value when performing the shift operation.

5. The showcase according to claim 4, characterized in that when the control unit performs the shift operation, it restricts the next shift operation until a preset restriction time has elapsed.

6. The showcase according to claim 5, characterized in that the control unit performs a shift release operation to return the cooling stop temperature and the cooling start temperature to their initial values ​​when the internal temperature value detected by the internal temperature sensor becomes higher than or equal to a release value which is higher than the reference value.

7. The showcase according to claim 6, characterized in that when a defrosting operation is performed to remove frost adhering to the evaporator constituting the cooling means, the control unit restricts the shift operation from the start of the defrosting operation until a predetermined waiting time has elapsed after the completion of the defrosting operation.

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