JP3889534B2 - Control device for refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a control device for a refrigerator connected to a cooling load such as a showcase installed indoors.
[0002]
[Prior art]
Generally, it is a refrigerator connected to a showcase having a night cover and an interior illuminator installed indoors, and is equipped with a compressor capable of capacity control. The low pressure pressure and the set pressure on the suction side of this compressor And a control device for a refrigerator having means for controlling the capacity of the compressor according to the comparison result.
[0003]
In this type of conventional control device, the set pressure is set by the contractor and is controlled throughout the year with the set pressure value, or when this set value is changed, the temperature of the showcase or the showcase is set. Control for changing the set pressure is performed based on load information such as the opening / closing frequency of the connected liquid solenoid valve.
[0004]
[Problems to be solved by the invention]
However, there is a problem that optimal operation control cannot be performed when the control is performed throughout the year with the set pressure value once set.
[0005]
Even in the case of performing control to change the set pressure, the conventional configuration requires a controller that constantly monitors the load information of each showcase. This type of controller is generally provided integrally with a showcase, and when controlling a showcase that does not have this controller, it is not possible to perform control to change the set pressure. There is a problem of lacking. Moreover, the conventional controller is expensive.
[0006]
Therefore, an object of the present invention is to provide a refrigerator control device that is excellent in so-called versatility, which can solve the above-described problems of the prior art and can perform control to change the set pressure by a refrigerator alone. There is.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a refrigerator connected to a cooling load such as a showcase installed indoors, and includes a compressor capable of capacity control, and the pressure and setting on the suction side of the compressor In the control device of the refrigerator having a means for comparing the pressure and controlling the capacity of the compressor according to the comparison result, a temperature sensor for detecting the outdoor temperature and a reference temperature according to the installation environment of the refrigerator a reference temperature changing means for changing the, in which a set pressure changing means for changing the set pressure in accordance with said reference temperature and the detected outdoor temperature by the temperature sensor.
[0008]
According to a second aspect of the present invention, in the refrigerator control device according to the first aspect, a humidity sensor that detects outdoor humidity, an outdoor temperature detected by the temperature sensor, the reference temperature, and the humidity sensor are detected. Set pressure changing means for changing the set pressure in accordance with the outdoor humidity.
[0009]
According to a third aspect of the present invention, in the refrigerator control device according to the first or second aspect, a plurality of the temperature sensors are provided outside the room, and the set pressure changing means is a temperature detected by the plurality of temperature sensors. The set pressure is changed according to the average value.
[0010]
According to a fourth aspect of the present invention, in the control device for a refrigerator according to the second aspect, a plurality of the humidity sensors are provided outside the room, and the set pressure changing means sets an average value of the detected humidity by the plurality of humidity sensors. Accordingly, the set pressure is changed.
[0011]
The invention according to claim 5 is the refrigerator control device according to claim 1 or 2, wherein the cooling load of the showcase or the like includes an interior illuminator, wherein the interior illuminator There is provided a set pressure changing means for changing the set pressure to a high pressure when is turned off.
[0012]
The invention according to claim 6 is the refrigerator control device according to claim 1 or 2, wherein the cooling load of the showcase or the like includes a night cover and an interior lighting device, wherein the night A set pressure changing means is provided for changing the set pressure to a high pressure when the cover is put on and the inside illuminator is turned off.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0014]
In FIG. 1, reference numeral 1 denotes a refrigerator, and a plurality of open showcases 5 are connected in parallel to the refrigerator 1 via a refrigerant pipe 3. The refrigerator 1 includes a compressor 11 and a condenser 13, and each open showcase 5 includes a decompression device 14 and a cooler 15. A liquid electromagnetic valve 17 is provided at the inlet of each decompression device 14. It is connected. The compressor 11 is an electric compressor, and an inverter 21 for drive control is connected to the electric compressor, and a controller 23 is connected to the inverter 21.
[0015]
The controller 23 includes a microcomputer 25 as shown in FIG.
[0016]
The microcomputer 25 is provided with a low pressure sensor 27 for detecting a low pressure on the suction side of the compressor 11, a pressure setter 29 for setting a set pressure to be compared with the low pressure, and a plurality of open showcases 5. Temperature sensor 31 for detecting outdoor temperature in the vicinity of a supermarket, etc., humidity sensor 33 for detecting humidity outside the room, and presence / absence of a cover for detecting the presence or absence of a night cover (not shown) of each open showcase 5 The detector 35 is connected to a turn-off detector 37 that detects the turn-off of the interior illuminator (not shown) of the showcase 5. In some cases, the extinction detector 37 may be used instead of the cover presence detector 35 . The room is generally a store, but may be a room such as a warehouse.
[0017]
The night cover attached to the showcase 5 is normally put on the opening of the showcase 5 for keeping the inside cold when the store is closed.
[0018]
Next, the operation will be described.
[0019]
When the refrigerator 1 is connected to each showcase 5, first, as shown in FIG. 3, the contractor sets a reference pressure related to the low-pressure pressure on the suction side of the compressor 11, which serves as a reference for changing the operating frequency of the compressor 11. For example, a high value PH = 2.5 Kg / cm 2 and a low value PL = 2.0 Kg / cm 2 are set in the microcomputer 25.
[0020]
Thereafter, the microcomputer 25 controls the operating frequency of the compressor 11 according to the flow shown in FIG. That is, the low pressure detection sensor 27 detects the low pressure PS on the suction side of the compressor 11 (S1), and compares the low pressure PS with the high value PH or the low value PL as the set pressure described above ( S2).
[0021]
When the low pressure PS is higher than the high value PH (A region in FIG. 2), it is checked whether or not the current operation frequency of the compressor 11 is 80 Hz (S3). In order to increase, the operating frequency of the compressor 11 is increased (S4), and if it is 80 Hz, the operating frequency is maintained as it is (S5).
[0022]
On the other hand, when the low pressure PS is lower than the low value PL in S2 (C region in FIG. 2), it is checked whether the current operating frequency of the compressor 11 is 20 Hz (S6). If so, the operation frequency of the compressor 11 is lowered to lower the cooling capacity (S7), and if it is 20 Hz, the operation of the compressor 11 is stopped (S8). If the low pressure PS is between the high value PH and the low value PL (B region in FIG. 2) in S2, the operation frequency of the compressor 11 is maintained as it is (S5).
[0023]
In this embodiment, the temperature sensor 31 detects the outdoor temperature in the vicinity of a supermarket or the like where the open showcase 5 is installed, and this outdoor temperature Ta is taken into the microcomputer 25 as shown in FIG. ).
[0024]
The outdoor temperature Ta in a supermarket or the like directly affects the load on each showcase 5. That is, when the outdoor temperature Ta is high, the load on each showcase 5 is large, and when the outdoor temperature Ta is low, the load on each showcase 5 is small. Therefore, according to the outdoor temperature Ta, The magnitudes of the high value PH and the low value PL (set pressure) are changed.
[0025]
FIG. 6 shows a change characteristic P between the high value PH and the low value PL. For example, when the outdoor temperature Ta is close to the reference temperature Tk = 20 ° C., the high value PH and the low value PL are not changed because the load on each showcase 5 is not affected.
[0026]
On the other hand, as shown in FIG. 5, the outdoor temperature Ta and the reference temperature Tk are compared (S11). When the outdoor temperature Ta is lower than the reference temperature Tk, the high value PH and the low temperature are changed according to the change characteristics shown in FIG. The value PL is changed (S12).
[0027]
That is, when the outdoor temperature Ta is lower than the reference temperature Tk, the load on each showcase 5 is reduced. Therefore, as shown in FIG. 6, the high value PH and the low value PL are gradually increased to increase the outdoor temperature. When Ta is less than about 15 ° C., the high value PH and the low value PL are moved by +0.3 kg / cm 2, respectively, and as shown in FIG. 7, the high value PH is 2.8 kg / cm 2 and the low value PL is 2.3 kg. Change to / cm2.
[0028]
In S11 of FIG. 5, when the outdoor temperature Ta is higher than the reference temperature Tk, the load on the showcase 5 increases, so the high value PH and the low value PL are changed to be lower according to the changing characteristics shown in FIG. 6 (S13). ).
[0029]
Referring to FIG. 6, when outdoor temperature Ta exceeds about 25 ° C., high value PH and low value PL are moved by −0.3 Kg / cm 2, respectively, and high value PH = 2.2 Kg / cm 2 and low value PL = Change to 1.7 Kg / cm2.
[0030]
The microcomputer 25 described above controls the high value PH and the low value PL. This microcomputer 25 constitutes a set pressure changing means.
[0031]
As described above, when the high value PH and the low value PL are changed, the operating frequency of the compressor 11 is changed according to the flow shown in FIG. 4 using the changed high value PH and low value PL. Is controlled.
[0032]
In this embodiment, a plurality of temperature sensors 31 can be provided outside the room. In this case, the microcomputer 25 calculates the average value of the temperature detected by the plurality of temperature sensors 31, and changes the set pressure according to the average value.
[0033]
In this embodiment, the reference temperature Tk shown in FIG. 6 can be changed according to the specifications of the showcase 5 or the outdoor conditions of the supermarket. This change is controlled by the microcomputer 25. In this case, when changing the reference temperature Tk = 20 ° C. to, for example, 22 ° C., the microcomputer 25 calculates the pressure transfer value based on the graph obtained by translating the change characteristic P graph to the right by 2 ° C. When Tk = 20 ° C. is changed to 18 ° C., for example, the pressure transfer value is calculated based on the graph obtained by translating the graph of the change characteristic P to the left by 2 ° C.
[0034]
As another embodiment, not only the outdoor temperature described above but also the humidity of the humidity sensor 33 is taken in, the thermal load due to the outdoor temperature and the outdoor humidity is calculated, and the set pressure described above is changed according to this value. Good.
[0035]
Furthermore, the humidity of the humidity sensor 33 may be taken in and the set pressure may be changed according to the outdoor humidity. A plurality of humidity sensors 33 can be provided outside the room. In this case, the microcomputer 25 calculates the average value of the detected humidity at the plurality of humidity sensors 33 and changes the set pressure according to the average value.
[0036]
As another embodiment, as shown in FIG. 8, it is possible to control to change the set pressure depending on the presence or absence of a night cover (not shown) provided in the showcase 5. The presence or absence of the night cover is determined (S21). If there is no night cover, the high value PH and the low value PL are not changed as set (S22).
[0037]
In the case where there is a night cover, the night cover is put on when the supermarket is closed, and the interior lighting device (not shown) is turned off. As a result, the load on the showcase 5 is greatly reduced.
[0038]
Therefore, in this embodiment, when there is a night cover, when the turn-off detector 37 detects the turn-off of the interior illuminator (S23), the set pressure (high value PH and low value PL) is changed to a high pressure ( S24). For example, the high value PH and the low value PL are moved by +0.3 kg / cm 2, respectively. When the turn-off detector 37 does not detect the turn-off of the interior illuminator (S23), the high value PH and the low value PL are not changed as set (S22).
[0039]
Note that the control may be performed only by the output from the extinction detector 37 without providing the cover presence / absence detector 35.
[0040]
In any of the embodiments, when executing this control, there is no need for a controller that constantly monitors load information of each showcase as in the past, and if there is an outdoor temperature sensor, an outdoor humidity sensor, etc. Control of changing the set pressure is possible even in a showcase that does not have the controller, and a control device for a refrigerator that is excellent in so-called versatility is provided.
[0041]
As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this. In the above embodiment, the inverter refrigerator has been described. However, the present invention is not limited to this, and the present invention can also be applied to a multi refrigerator, an inverter multi refrigerator, or the like.
[0042]
【The invention's effect】
In the present invention, unlike the prior art, there is no need for a controller that constantly monitors the load information of each showcase, and if there is an outdoor temperature sensor, an outdoor humidity sensor, etc., there is no controller that constantly monitors the load information. Even in a showcase, control for changing the set pressure is possible, and the versatility is excellent.
[0043]
In addition, the control of the showcase has a load increase or decrease delayed from the change in outdoor conditions.In the present invention, the outdoor air temperature, which is an outdoor condition, is directly detected and controlled. Control can be performed quickly and smoothly in response to the increase or decrease.
[Brief description of the drawings]
FIG. 1 is a system diagram in which a refrigerator is connected to a showcase.
FIG. 2 is a control block diagram showing an embodiment of a refrigerator control device according to the present invention.
FIG. 3 is a diagram showing the relationship between low pressure and operating frequency.
FIG. 4 is a flowchart of normal operation.
FIG. 5 is a flowchart of setting pressure change.
FIG. 6 is a diagram illustrating a change characteristic of a set pressure according to the outdoor temperature.
FIG. 7 is a diagram showing a set pressure at an outdoor temperature of 15 ° C.
FIG. 8 is a flow chart of setting pressure change showing another embodiment.
[Explanation of symbols]
1 Refrigerator 5 Open showcase 11 Compressor 21 Inverter 25 Microcomputer (set pressure changing means)
27 Low pressure sensor 29 Pressure setter 31 Temperature sensor 33 Humidity sensor 35 Cover presence detector 37 Light off detector

Claims (6)

A refrigerator connected to a cooling load such as a showcase installed indoors,
In a control device for a refrigerator having a compressor capable of capacity control, and having a means for comparing the pressure on the suction side of the compressor with a set pressure and controlling the capacity of the compressor according to the comparison result ,
A temperature sensor for detecting the outdoor temperature;
Reference temperature changing means for changing the reference temperature according to the installation environment of the refrigerator ;
A control apparatus for a refrigerator , comprising: an outdoor temperature detected by the temperature sensor ; and a set pressure changing unit that changes the set pressure according to the reference temperature . A humidity sensor for detecting outdoor humidity;
2. A set pressure changing unit that changes the set pressure according to an outdoor temperature detected by the temperature sensor, the reference temperature, and an outdoor humidity detected by the humidity sensor. Refrigerator control device. The said temperature sensor is provided with two or more by the outdoors, and the said setting pressure change means changes the said setting pressure according to the average value of the detected temperature in several temperature sensor. Refrigerator control device. 3. The refrigerator according to claim 2, wherein a plurality of the humidity sensors are provided outside the room, and the set pressure changing unit changes the set pressure in accordance with an average value of the humidity detected by the plurality of humidity sensors. Control device. The cooling load such as the showcase is a refrigerator having an interior lighting device,
The control device for a refrigerator according to claim 1 or 2, further comprising set pressure changing means for changing the set pressure to a high pressure when the interior illuminator is turned off. The cooling load such as the showcase is a refrigerator having a night cover and an interior illuminator,
3. The set pressure changing means for changing the set pressure to a high pressure when the night cover is put on and the interior illuminator is turned off. Control device for refrigerator.

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