JP2019090552A - Control device, refrigerator, control method and program - Google Patents

Abstract

To provide a control device for a refrigerator that can perform, even when a different refrigerant is used for the refrigerator, overheating degree control suitable to the refrigerant.SOLUTION: A control device 2 comprises: a pressure acquisition part which acquires exit pressure of an evaporator 6 from a pressure sensor 7 detecting the pressure of a refrigerant at an exit of the evaporator 6; a temperature acquisition part which acquires an exit temperature of the evaporator 6 from a temperature sensor 8 detecting the temperature of the refrigerant at the exit of the evaporator 6; a saturation temperature table acquisition part which acquires one of a plurality of saturation temperature tables recorded in a recording part 4, the plurality of saturation temperature tables corresponding to different refrigerants and a saturation temperature table specifying a gas-side saturation temperature at each pressure of the corresponding refrigerant; and an expansion valve control part which controls, based upon the acquired saturation temperature table, the acquired exit pressure, and the acquired exit temperature, an expansion valve opening of an electronic expansion valve 5 in the refrigerator so as to obtain a predetermined overheating degree.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device, a refrigerator, a control method, and a program.

  Control of the degree of superheat of refrigerant in a refrigerator is an important technology in terms of compressor protection and maximization of refrigeration efficiency. On the other hand, when making a refrigerator corresponding to a plurality of different refrigerants, different refrigerant designs are usually required because the saturation temperature at each pressure is different for each refrigerant. As a technique for performing superheat degree control corresponding to different refrigerants, Patent Document 1 below discloses setting an initial valve opening degree of an electronic valve that conforms to the characteristics of the refrigerant before the start of the refrigeration operation.

Japanese Patent Application Laid-Open No. 61-036671

  At present, R404A is widely used as a refrigerant of a vapor compression refrigerator. On the other hand, the global warming potential (GWP) value of R404A is 3922 (Intergovernmental Panel Fourth Assessment Report on Climate Change (IPCC AR4)) and has a high value. Since there is a situation where switching to a low GWP refrigerant is urgent, many low GWP mixed refrigerants (R448A, R449, and R452A, etc.) whose physical properties are close to R404A have been proposed by each refrigerant manufacturer. Under such circumstances, if a refrigerator design operates with a specific alternative refrigerant, there is no guarantee that the adopted alternative refrigerant will be stably supplied in the future, and in the worst case, the refrigerant can not be obtained and after service Is concerned that it can not provide.

  Furthermore, since the provision status of the refrigerant in each country is different due to various circumstances, it is not always possible to obtain the necessary refrigerant. Therefore, there is also a problem that a transport refrigerant moving between countries can not necessarily obtain a desired refrigerant when it is necessary to exchange the refrigerant due to various reasons such as leakage of the refrigerant.

  This invention is made in view of the said subject, Comprising: Even if it is a case where a different refrigerant | coolant is used for a refrigerator, the objective is the refrigeration which can perform superheat degree control suitable for the refrigerant | coolant It is providing a control device of a machine, a refrigerator, a control method, and a program. In the embodiment of the present invention, the recording unit has a saturation temperature table corresponding to a plurality of types of refrigerants, and the control device of the refrigerator selects one suitable from the plurality of saturation temperature tables recorded. By doing this, it is possible to handle different refrigerants.

  According to the first aspect of the present invention, the control device that controls the refrigerator according to different refrigerants is a pressure sensor that detects the pressure of the refrigerant at the outlet of the evaporator in the refrigerator, and the outlet of the evaporator A temperature acquisition unit for acquiring the outlet temperature of the evaporator from a pressure acquisition unit for acquiring pressure, a temperature sensor for detecting the temperature of the refrigerant at the outlet of the evaporator, and a refrigerant corresponding to the acquired outlet pressure And an expansion valve control unit configured to control an expansion valve opening degree of an electronic expansion valve in the refrigerator so as to obtain a predetermined degree of superheat based on the gas-side saturation temperature and the acquired outlet temperature.

  According to a second aspect of the present invention, the control device according to the first aspect is a saturation temperature table acquisition unit for acquiring one of a plurality of saturation temperature tables recorded in a recording unit in the refrigerator. And each of the plurality of saturation temperature tables corresponds to a different refrigerant, and the saturation temperature table further includes a saturation temperature table acquisition unit that specifies the gas side saturation temperature at each pressure for the corresponding refrigerant, The expansion valve control unit determines a gas-side saturation temperature of the refrigerant corresponding to the acquired outlet pressure based on the acquired saturation temperature table.

  Further, according to the third aspect of the present invention, the control device according to the first aspect further includes a refrigerant selection signal acquisition unit for acquiring a signal indicating selection of a specific refrigerant from the control interface of the refrigerator. The saturation temperature table acquiring unit may select a saturation temperature table corresponding to the specific refrigerant from the plurality of saturation temperature tables based on a signal indicating selection of the specific refrigerant.

  Moreover, according to the 4th aspect of this invention, the said recording part records the information of the allowable pressure information of the said refrigerator, The control apparatus which concerns on a said 1st aspect is the said recording based on the said allowable pressure. Providing a control interface of the refrigerator with a compatible refrigerant determination unit for determining a refrigerant compatible with the refrigerator from the refrigerants corresponding to a plurality of saturation temperature tables recorded in the storage unit, and information of the determined refrigerant And a compatible refrigerant information provision unit.

  Moreover, according to the 5th aspect of this invention, the said recording part records the information of the lubricating oil used with the said refrigerator, The control apparatus which concerns on a said 1st aspect is the information of the said lubricating oil. Based on the refrigerant corresponding to the plurality of saturation temperature tables recorded in the recording unit, a compatible refrigerant determination unit that determines a refrigerant that conforms to the refrigerator, and information on the determined refrigerant, the control of the refrigerator And a compatible refrigerant information provider provided to the interface.

  Further, according to a sixth aspect of the present invention, the control device according to the fourth or fifth aspect acquires a refrigerant selection signal acquisition unit that acquires a signal indicating selection of a specific refrigerant from a control interface of the refrigerator. And a warning information providing unit for providing warning information to a control interface of the refrigerator, when the signal indicating the selection of the specific refrigerant indicates the selection of a refrigerant other than the refrigerant compatible with the refrigerator. .

  Further, according to a seventh aspect of the present invention, the refrigerator is a transport refrigerator.

  Further, according to the eighth aspect of the present invention, the expansion valve control unit determines the current degree of superheat by subtracting the gas side saturation temperature of the refrigerant from the acquired outlet temperature, and the current superheat is determined. The degree of expansion of the electronic expansion valve in the refrigerator is controlled so that the degree approaches the predetermined degree of superheat.

  Further, according to the ninth aspect of the present invention, at least one of the refrigerants corresponding to the plurality of saturation temperature tables is a refrigerant having temperature glide characteristics.

  Further, according to the tenth aspect of the present invention, a refrigerator operating according to different refrigerants evaporates the refrigerant expanded by the electronic expansion valve capable of freely changing the expansion valve opening degree and the electronic expansion valve. An evaporator, a pressure sensor for detecting the pressure of the refrigerant at the outlet of the evaporator, and a temperature sensor for detecting the temperature of the refrigerant at the outlet of the evaporator, wherein the control unit is detected by the pressure sensor The expansion valve opening degree of the electronic expansion valve is controlled so as to obtain a predetermined degree of superheat based on the gas side saturation temperature of the refrigerant corresponding to the pressure and the temperature detected by the temperature sensor. Configured

  Further, according to an eleventh aspect of the present invention, a method of controlling a refrigerator according to different refrigerants comprises: a pressure sensor for detecting a pressure of the refrigerant at an outlet of the evaporator in the refrigerator; Obtaining an outlet pressure, obtaining an outlet temperature of the evaporator from a temperature sensor detecting a temperature of the refrigerant at the outlet of the evaporator, and gas side saturation of refrigerant corresponding to the obtained outlet pressure Controlling an expansion valve opening degree of an electronic expansion valve in the refrigerator so as to obtain a predetermined degree of superheat based on the temperature and the acquired outlet temperature.

  Further, according to a twelfth aspect of the present invention, a program causes a computer of a refrigerator to execute the method according to the tenth aspect.

  According to the above-described refrigerator control device, refrigerator, refrigerator control method, and program, even if different refrigerants are used in the refrigerator, superheat degree control suitable for the refrigerant may be performed. It is possible. Therefore, even in a situation where the refrigerant conversion timing and directionality are different for each region, the used refrigerant can be selected while maintaining the same device design. Therefore, multiple refrigerants can be used without inhibiting the cost reduction effect of mass production of the device. It is possible to cope with Also, in the future, if alternative cooling selection and concentration progress, drop-in use of available refrigerant will be facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole structure of the refrigerator which concerns on 1st Embodiment. It is a figure which shows the function structure of the control part which concerns on 1st Embodiment. It is a figure which shows the phase change of refrigerant | coolant R404A in a ph diagram. It is a figure which shows the phase change of refrigerant | coolant R452A in a ph diagram. It is a figure which shows the example of the saturation temperature table recorded on the recording part of the refrigerator which concerns on 1st Embodiment. It is a figure which shows the processing flow of the control part which concerns on 1st Embodiment. It is a figure which shows the function structure of the control part which concerns on 2nd Embodiment. It is a figure which shows the processing flow of the control part which concerns on 2nd Embodiment.

First Embodiment
Hereinafter, the refrigerator according to the first embodiment will be described with reference to FIGS. 1 to 6.

(Configuration of refrigerator)
FIG. 1 is a view showing the configuration of a refrigerator according to the first embodiment.
The refrigerator 1 according to the first embodiment is assumed to be used as a transport refrigerator mounted on a truck, a train, an aircraft, and the like. On the other hand, in the other embodiment, the refrigerator 1 is not limited to the usage mode as described above, and may be used as a general refrigerator.

  The refrigerator 1 according to the first embodiment includes a control unit 2, a control interface 3, a recording unit 4, an electronic expansion valve 5, an evaporator 6, a pressure sensor 7, a temperature sensor 8, and a compressor 9. And a condenser 10. As FIG. 1 shows, the electronic expansion valve 5, the evaporator 6, the compressor 9, and the condenser 10 are sequentially annularly connected by piping through which a refrigerant | coolant passes, and comprise a refrigerating cycle.

  The control unit 2 acquires one of a plurality of saturation temperature tables corresponding to different refrigerants from the recording unit 4, and the electronic expansion in the refrigerator is performed so as to obtain a predetermined degree of superheat based on the acquired saturation temperature table. Control the expansion valve opening degree of the valve. The functional configuration of the control unit 2 will be described in more detail with reference to FIG. 2 below.

  The control interface 3 is a means for the operator to set the refrigerator, and provides the operator with a means for selecting the refrigerant. The control interface 3 may be implemented by any user interface for conveying the intention of the operator to the control unit 2. For example, it is conceivable that the control interface 3 is implemented as a physical switch such as a dip switch on a substrate or as a touch sensor provided on a touch display. The operator can select any of the available refrigerants at the control interface 3. The control unit 2 acquires a saturation temperature table corresponding to the selected refrigerant from the plurality of saturation temperature tables recorded in the recording unit 4 in response to the refrigerant selection by the operator.

  The recording unit 4 records a plurality of saturation temperature tables corresponding to different refrigerants. The saturation temperature table represents the gas side saturation temperature of the refrigerant with respect to each pressure. The control unit 2 acquires one from the plurality of saturation temperature tables recorded in the recording unit 4 and performs superheat degree control based on the acquired saturation temperature tables. The details of the saturation temperature table will be described in more detail below with reference to FIGS.

  The electronic expansion valve 5 is connected between the condenser 10 and the evaporator 6, and a high pressure liquid refrigerant flows from the condenser 10. The electronic expansion valve 5 regulates the pressure of the refrigerant after passing by adjusting the flow rate of the refrigerant to be passed according to the opening degree of the valve, and the gas-liquid mixed refrigerant which has a low pressure flows out to the evaporator 6 Do. The opening degree of the electronic expansion valve 5 can be dynamically adjusted and controlled by the control unit 2.

  The evaporator 6 is connected between the electronic expansion valve 5 and the compressor 9, and a low pressure refrigerant flows from the electronic expansion valve 5. The evaporator 6 has a function of evaporating the refrigerant expanded by the electronic expansion valve. Therefore, in the evaporator 6, all the refrigerant in the mixed state of the liquid phase and the gas phase is vaporized, heat exchange with the air is performed by heat absorption of the refrigerant, and as a result, the inside of the refrigerator in which the refrigerator is installed The air is cooled. From the viewpoint of refrigeration efficiency and compressor protection, at the outlet of the evaporator 6, it is desirable that the liquid phase and the gas phase become a completely vaporized refrigerant from the mixed refrigerant. Therefore, in order to ensure that the refrigerant is discharged in a completely vaporized state, the evaporator 6 converts the refrigerant into a superheated vapor at a temperature higher than the gas side saturation temperature and then discharges it to the compressor 9 side. The elevated temperature of the superheated steam relative to the gas side saturation temperature is generally referred to as the "superheat degree".

The pressure sensor 7 may be provided in a pipe or the like extending from the evaporator 6 to the compressor 9 and detects the pressure of the refrigerant at the outlet of the evaporator 6 (hereinafter referred to as “outlet pressure”). The pressure sensor 7 outputs the detected pressure to the control unit 2, and the control unit 2 uses the pressure detected by the pressure sensor 7 to calculate the degree of superheat.
Further, the temperature sensor 8 may be similarly provided in a pipe or the like extending from the evaporator 6 to the compressor 9, and detects the temperature of the refrigerant at the outlet of the evaporator 6 (hereinafter referred to as "outlet temperature"). The temperature sensor 8 outputs the detected pressure to the control unit 2, and the control unit 2 adds the temperature detected by the temperature sensor 8 to the pressure and uses it for calculation of the degree of superheat.

The compressor 9 is connected between the evaporator 6 and the condenser 10, and a low pressure gas refrigerant flows from the evaporator 6. The compressor 9 compresses the inflowing refrigerant into a high-pressure gas refrigerant and flows out to the condenser 10.
The condenser 10 is connected between the compressor 9 and the electronic expansion valve 5, and a high pressure gas refrigerant flows from the compressor 9. The condenser 10 releases heat from the high pressure gas refrigerant and flows out to the electronic expansion valve 5 as a high pressure liquid refrigerant.

  The refrigerator 1 cools the inside of a freezer mounted on, for example, a truck, a train, and an aircraft through the above-described refrigeration cycle. In the refrigerator 1 according to the first embodiment, the recording unit 4 records a plurality of saturated temperature tables corresponding to different refrigerants, and the control unit 2 acquires an appropriate one from among the plurality of saturated temperature tables. It is possible to perform appropriate superheat control. Hereinafter, a more detailed functional configuration of the control unit 2 will be described.

(Functional configuration of control unit)
FIG. 2 is a diagram showing a functional configuration of the control unit 2 according to the first embodiment.
As shown in FIG. 2, the control unit 2 includes a pressure acquisition unit 21, a temperature acquisition unit 22, a saturation temperature table acquisition unit 23, an expansion valve control unit 24, and a refrigerant selection signal acquisition unit 25. The control unit 2 is a processor (microcomputer) which controls the entire refrigerator 1 and operates in accordance with a program prepared in advance. Further, the control unit 2 is electrically coupled to the recording unit 4, the electronic expansion valve 5, the pressure sensor 7, and the temperature sensor 8.

  Further, as shown in FIG. 2, the recording unit 4 records a saturation temperature table corresponding to a plurality of refrigerants. As described above, the saturation temperature table represents the gas side saturation temperature with respect to each pressure of the refrigerant. In general, different refrigerants have different gas side saturation temperatures for each pressure. For example, the boundaries of phase change in the ph diagrams (Moriel diagrams) of refrigerants R404A and R452A are shown in FIGS. The saturation temperature table is a table representing the relationship between the pressure in the graph and the gas side saturation temperature.

  Furthermore, in FIG. 3, the refrigeration cycle of the refrigerator on the ph diagram is shown as a dotted line. The bottom portion of the inverted trapezoid in this refrigeration cycle indicates the change in state of the refrigerant in the evaporator. When the refrigerant passes through the electronic expansion valve 5, the refrigerant flows into the evaporator at low pressure and low temperature. In the evaporator, the refrigerant changes from the mixed state of the liquid phase and the gas phase to the gas phase under substantially equal pressure conditions. On the other hand, as described above, in order to ensure complete vaporization of the refrigerant, the refrigerant is heated by the degree of superheat than the gas side saturation temperature, and is discharged to the compressor 9 side. In FIG. 3, the arrow of (1) shows the state of the evaporator outlet, and the arrow of (2) shows the state at the gas side saturation temperature. In the present invention, the degree of superheat is calculated as a value obtained by subtracting the gas side saturation temperature from the evaporator outlet temperature.

The saturation temperature table is recorded in the recording unit 4 as a table as shown in FIG. 5, for example. Although FIG. 5 shows a saturation temperature table for three refrigerants as an example, the saturation temperature table for any number of refrigerants may be recorded in the recording unit 4. For example, the saturation temperature table for the refrigerant A, for each pressure _{(P 1, P 2, P} 3), the gas side saturation temperature of the refrigerant _{(T A1, T A2, T} A3) is associated. Further, in the saturation temperature table for the refrigerant B, the gas side saturation temperature (T _B1 , T _B2 , T _B3 ) of the refrigerant is associated with each pressure (P ₁ , P ₂ , P ₃ ). Similarly, with respect to the refrigerant C, the gas side saturation temperatures (T _C1 , T _C2 , T _C3 ) of the refrigerant are associated with the respective pressures (P ₁ , P ₂ , P ₃ ). In FIG. 5, the gas side saturation temperature is explicitly associated with only three pressures, but this is merely an example, and the saturation temperature table is for any number of pressures at any intervals. The gas side saturation temperature may be associated.
In addition, although it is assumed that the saturation temperature table is recorded in advance in the recording unit 4 at the time of manufacture, it is acquired from the network via wireless or wired as required, or acquired from other external recording media May be recorded and updated as needed.

  Returning to FIG. 2, the pressure acquisition unit 21 acquires the outlet pressure from the pressure sensor 7 that detects the pressure of the refrigerant at the outlet of the evaporator 6. Further, the temperature acquisition unit 22 acquires the outlet temperature from the temperature sensor 8 that detects the temperature of the refrigerant at the outlet of the evaporator 6. The pressure acquiring unit 21 and the temperature acquiring unit 22 can acquire measured values of each sensor continuously or at predetermined time intervals. The acquired outlet pressure and outlet temperature of the evaporator 6 are used by the expansion valve control unit 24 to determine and control the degree of superheat.

  The refrigerant selection signal acquisition unit 25 acquires a signal corresponding to the refrigerant selected by the operator in the control interface 3 from the control interface 3. As described above, the control interface 3 may be implemented by any form such as a physical switch on a base or a touch sensor on a touch display. The operator can select the intended refrigerant at the control interface 3, and the refrigerant selection signal acquisition unit 25 acquires a signal reflecting the refrigerant selection of the operator.

  The saturation temperature table acquisition unit 23 acquires one of the plurality of saturation temperature tables recorded in the recording unit 4. The saturation temperature table acquisition unit 23 can select one of the plurality of saturation temperature tables based on the initial setting or the signal acquired by the refrigerant selection signal acquisition unit.

  The expansion valve control unit 24 determines a predetermined degree of superheat based on the saturation temperature table acquired by the saturation temperature table acquisition unit 23, the outlet pressure acquired by the pressure acquisition unit 21, and the outlet temperature acquired by the temperature acquisition unit 22. To control the expansion valve opening degree of the electronic expansion valve 5 in the refrigerator. This degree of superheat control will be described in more detail below.

  In the first embodiment, the refrigerant selection signal acquisition unit 25 acquires the refrigerant selection signal from the control interface 3 and the appropriate saturation temperature table is selected based on the refrigerant selection signal, but in the other embodiments, The control unit 2 may automatically determine the refrigerant to be used, and select an appropriate saturation temperature table based on the determination. In such an embodiment, the control unit 2 may include a refrigerant determination unit 26 (not shown) that determines the refrigerant used for the refrigerator 1 instead of the refrigerant selection signal acquisition unit 25. The saturation temperature table acquisition unit 23 can select one of the plurality of saturation temperature tables based on the determined refrigerant.

FIG. 6 is a diagram showing a process flow of the control unit 2 according to the first embodiment.
Before the process flow of FIG. 6 starts, the operator can select the refrigerant to be used through the control interface 3. For example, when the refrigerant needs to be replaced due to a failure or the like, a situation in which the currently used refrigerant can not be used is assumed. In such a case, the operator selects the setting on the control interface 3 corresponding to the new refrigerant that has been replaced. As mentioned above, the control interface 3 may be implemented as a user interface that allows the operator to select refrigerant in any form. After such setting is made, the following processing flow may be started. Note that the order of each processing step described below is merely exemplified for ease of explanation, and the order of some processing steps may be changed or may be performed in parallel.

  In step S101, the control unit 2 obtains the outlet pressure of the evaporator 6 from a pressure sensor that detects the outlet pressure of the evaporator 6 in the refrigerator 1. Furthermore, in step S102, the control unit 2 obtains the outlet temperature of the evaporator 6 from the temperature sensor that detects the outlet temperature of the evaporator 6. The acquisition of the outlet pressure and the outlet temperature may be performed continuously as long as the operation of the refrigerator 1 continues in order to control the degree of superheat of the refrigerator 1.

  In step S103, the control unit 2 acquires a corresponding one from the plurality of saturation temperature tables recorded in the recording unit 4 in the refrigerator 1. The plurality of saturation temperature tables include saturation temperature tables corresponding to different refrigerants, each saturation temperature table specifying a gas-side saturation temperature for each pressure for a particular refrigerant. In step S103, specifically, the control unit 2 obtains a signal indicating the refrigerant selected by the operator from the control interface 3 of the refrigerator 1, and the corresponding saturation based on the signal indicating the selected refrigerant. The saturated temperature table may be acquired by executing the step of selecting the temperature table from the plurality of saturated temperature tables recorded in the recording unit 4. The acquisition of the saturation temperature table is different from the step S101 and the step S102, and the processing is sufficient if it is performed once in the operation of the refrigerator 1, and the acquired saturation temperature table is a memory in the processor constituting the control unit 2. Or the like, and may be referred to at any time by the control unit 2.

In S104, the control unit 2 of the electronic expansion valve 5 in the refrigerator 1 so as to obtain a predetermined degree of superheat based on the acquired saturation temperature table, the acquired outlet pressure, and the acquired outlet temperature. Control the degree of expansion valve opening.
In detail, the control unit 2 may first calculate the current degree of superheat. That is, the control unit 2 can determine how many times the gas side saturation temperature is with respect to the acquired current outlet pressure of the evaporator 6 with reference to the acquired saturation temperature table. Furthermore, the control unit 2 can determine the current degree of superheat by subtracting the determined gas side saturation temperature of the refrigerant from the acquired outlet temperature. Furthermore, the control unit 2 can control the expansion valve opening degree of the electronic expansion valve 5 so that the current degree of superheat approaches the predetermined degree of superheat. For example, the pressure in the evaporator 6 can be reduced by opening the opening degree of the electronic expansion valve 5 from the current state. As apparent from FIGS. 3 to 6, the gas side saturation temperature also changes correspondingly, so the degree of superheat also changes. Using such a process, the expansion valve control unit 24 controls the electronic expansion valve 5 so as to obtain an appropriate degree of superheat. Step S104 may be performed continuously as long as the operation of the refrigerator 1 continues.

  As described above, in the present invention, the degree of superheat is determined by determining the gas-side saturation temperature from the saturation temperature table and measuring the outlet temperature of the evaporator 6. On the other hand, such a configuration enables more accurate control of the degree of superheat as compared with the method of measuring the inlet temperature of the evaporator 6 as the gas side saturation temperature and calculating the degree of superheat from the difference with the outlet temperature. For example, as the refrigerant R 452A in FIG. 4 shows, temperature change may occur even in the mixed region of the gas phase and the liquid phase even under the equal pressure state, and such a characteristic is called “temperature glide characteristic”. A refrigerant having temperature glide characteristics has a problem that the inlet temperature of the evaporator 6 is different from the gas side saturation temperature of the refrigerant. Therefore, as in the present invention, by calculating the gas side saturation temperature directly from the saturation temperature table, it is possible to know more accurate degree of superheat and to perform superheat degree control more accurately.

(Operation and effect of the first embodiment)
As described above, according to the refrigerator 1 according to the first embodiment, even when different refrigerants are used for the refrigerator 1, the recording temperature of the recording unit 4 of the refrigerator 1 corresponds to a plurality of refrigerants. Having a table, it is possible to perform optimal superheat control by selecting a saturation temperature table corresponding to the refrigerant used.

Second Embodiment
In the second embodiment of the present application, in addition to the configuration of the control unit 2 of the first embodiment, a function is provided which enables the operator to select only the compatible refrigerant. Thus, the second embodiment of the present application discloses additional configurations that are optionally applicable to the first embodiment.

Generally, the refrigerator has an allowable pressure, which is derived from the allowable pressure of the refrigerant container and the like. Therefore, it is practically impossible for the refrigerator to be compatible with all the refrigerants, and the refrigerator is compatible with the refrigerant having a predetermined pressure characteristic. Moreover, although lubricating oils, such as polyol ester (POE) oil, are used for a refrigerator, the refrigerant | coolant suitable also for each lubricating oil exists.
In the second embodiment of the present application, in view of the above, the refrigerator is configured such that the operator can select a suitable refrigerant under predetermined conditions of the refrigerator.

  FIG. 7 is a diagram showing further functional configurations included in the control unit 2 and the recording unit 4 in addition to the functional configurations of the control unit 2 and the recording unit 4 shown in FIG. In order to facilitate the description, in FIG. 7, the description of each component of the control unit 2 described in FIG. 2 is omitted.

  The recording unit 4 includes information on the allowable pressure of the refrigerator 1 (hereinafter referred to as “allowable pressure information”) in addition to the saturation temperature table, and information on the lubricating oil used for the refrigerator 1 (hereinafter referred to as “lubricating oil” And record information). The allowable pressure of the refrigerator 1 is determined in advance based on the design of the refrigerant container of the refrigerator 1 and the design of the other refrigerator 1.

  The control unit 2 further includes a compatible refrigerant determination unit 26, a compatible refrigerant information provision unit 27, and a warning information provision unit 28, in addition to the respective components (not shown) shown in FIG.

  From the refrigerant corresponding to the saturation temperature table recorded in the recording unit 4, the compatible refrigerant determination unit 26 determines the allowable pressure of the refrigerator 1 and the allowable pressure information and the lubricating oil information, which are recorded in the recording unit 4. A refrigerant compatible with the lubricating oil used in the refrigerator 1 (hereinafter referred to as “compatible refrigerant”) is determined. In the present embodiment, the compatible refrigerant is determined based on both of the allowable pressure information and the lubricating oil information, but in the other embodiments, the compatible refrigerant may be determined based on either one of the information.

  The compatible refrigerant information provision unit 27 provides the control interface 3 with information on the compatible refrigerant determined by the compatible refrigerant determination unit 26. In the case where the control interface 3 includes a display, only the adapted refrigerant can be made selectable by the operator by displaying the adapted refrigerant on the display. In addition, even when the control interface 3 is implemented by a physical switch, it is possible to notify the operator of the compatible refrigerant by specifying the switch corresponding to the compatible refrigerant by lighting the lamp or the like. On the other hand, not limited to such an embodiment, the control interface 3 may be configured to notify the operator of the compatible refrigerant in any form using information on the compatible refrigerant.

  The warning information providing unit 28 provides warning information to the control interface 3 when a nonconforming refrigerant is selected in the control interface 3. Specifically, the refrigerant selection signal acquisition unit 25 shown in FIG. 2 acquires a signal indicating the refrigerant selected by the operator from the control interface 3. The alert information providing unit 28 provides alert information to the control interface 3 when the selected refrigerant is other than the compatible refrigerant determined by the compatible refrigerant determination unit 26. The configuration is particularly useful when the control interface 3 includes a physical switch such as a dip switch provided on a substrate.

  Further, in addition to the above configuration, the control unit 2 can also perform control so as not to control the refrigerator 1 when a nonconforming refrigerant is selected. Moreover, in still another embodiment, the recording unit 4 can record information on which refrigerant is of ASHRAE safety grade A1 (non-toxic, non-combustible), and the control unit 2 can record safety class A1 of ASHRAE. The control interface 3 may be controlled so that only the refrigerant (non-toxic, non-combustible) can be selected by the operator.

FIG. 8 is a diagram showing a process flow of the control unit according to the second embodiment.
The process flow of FIG. 8 may be performed before the process flow shown in FIG. 6 starts.

In step S201, based on the allowable pressure information recorded in the recording unit 4 and the lubricating oil information, the control unit 2 matches the refrigerator 1 among the refrigerants corresponding to the saturation temperature table recorded in the recording unit 4. Determine the refrigerant.
In step S202, the control unit 2 provides the control interface 3 with information on the determined compatible refrigerant. The control interface 3 can notify the operator of the compatible refrigerant in any manner using the received information on the compatible refrigerant. Also, when the control interface 3 includes a display, only the compatible refrigerant may be displayed in a selectable manner. In this case, since the operator can select only the compatible refrigerant, step S203 described below may be omitted and the process described in FIG. 6 may be continued.
In step S203, the control unit 2 receives a signal indicating the selection of the refrigerant from the control interface 3, and determines whether the selected refrigerant is included in the determined compatible refrigerant.
If YES in step S203, that is, if the compatible refrigerant is selected in the control interface 3, the process of 2 of the control unit continues to the process flow of step S101 shown in FIG.
In the case of NO at step S203, that is, when an incompatible refrigerant is selected at the control interface 3, warning information is provided to the control interface 3 at step S204, and the provider is prompted to select an adapted refrigerant. In this case, the process may return to step S203 to determine whether the selected refrigerant is included in the determined compatible refrigerant.

(Action / effect)
As described above, according to the refrigerator 1 according to the second embodiment, the operator reliably selects the refrigerant compatible with the refrigerator without knowing the allowable pressure of the refrigerator and the conditions for the lubricating oil or the other refrigerant. It can be possible. Therefore, it is possible to prevent failure of the refrigerator due to the use of the incompatible refrigerant.

  In each of the above-described embodiments, the process of the control unit 2 described above is stored in the form of a program in a computer-readable recording medium, and the above-described various processes are performed by the computer reading and executing this program. To be done. The computer readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, and the like. Alternatively, the computer program may be distributed to a computer through a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, it may be a so-called difference file (difference program) that can realize the above-described functions in combination with a program already recorded in the computer system. Furthermore, in another embodiment, the control unit 2 of the refrigerator 1 may be configured by a single computer, or may be configured by a plurality of computers communicably connected.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

REFERENCE SIGNS LIST 1 refrigerator 2 control unit 3 control interface 4 recording unit 5 electronic expansion valve 6 evaporator 7 pressure sensor 8 temperature sensor 9 compressor 10 condenser 21 pressure acquisition unit 22 temperature acquisition unit 23 saturation temperature table acquisition unit 24 expansion valve control unit 25 Refrigerant Selection Signal Acquisition Unit 26 Applicable Refrigerant Determination Unit 27 Applicable Refrigerant Information Providing Unit 28 Warning Information Providing Unit

Claims (12)

A control device that controls a refrigerator according to different refrigerants, wherein
A pressure acquisition unit that acquires the outlet pressure of the evaporator from a pressure sensor that detects the pressure of the refrigerant at the outlet of the evaporator in the refrigerator;
A temperature acquisition unit that acquires the outlet temperature of the evaporator from a temperature sensor that detects the temperature of the refrigerant at the outlet of the evaporator;
The expansion valve opening degree of the electronic expansion valve in the refrigerator is controlled to obtain a predetermined degree of superheat based on the refrigerant gas side saturation temperature corresponding to the acquired outlet pressure and the acquired outlet temperature. And an expansion valve control unit. A saturation temperature table acquisition unit for acquiring one of a plurality of saturation temperature tables recorded in a recording unit in the refrigerator, wherein each of the plurality of saturation temperature tables corresponds to a different refrigerant, and the saturation temperature The table further comprises a saturation temperature table acquisition unit, which specifies the gas side saturation temperature at each pressure for the corresponding refrigerant,
The control device according to claim 1, wherein the expansion valve control unit determines a gas side saturation temperature of the refrigerant corresponding to the acquired outlet pressure based on the acquired saturation temperature table. The system further includes a refrigerant selection signal acquisition unit that acquires a signal indicating selection of a specific refrigerant from the control interface of the refrigerator,
The control device according to claim 2, wherein the saturation temperature table acquisition unit selects a saturation temperature table corresponding to the specific refrigerant from the plurality of saturation temperature tables based on a signal indicating selection of the specific refrigerant. The recording unit records information of an allowable pressure of the refrigerator,
A compatible refrigerant determination unit that determines a refrigerant compatible with the refrigerator from the refrigerants corresponding to the plurality of saturation temperature tables recorded in the recording unit based on the information of the allowable pressure;
The control device according to claim 2, further comprising: a compatible refrigerant information provision unit that provides the determined refrigerant information to a control interface of the refrigerator. The recording unit records information of lubricating oil used in the refrigerator,
A compatible refrigerant determination unit configured to determine a refrigerant compatible with the refrigerator from refrigerants corresponding to a plurality of saturation temperature tables recorded in the recording unit based on information of the lubricating oil;
The control device according to claim 2, further comprising: a compatible refrigerant information provision unit that provides the determined refrigerant information to a control interface of the refrigerator. A refrigerant selection signal acquisition unit for acquiring a signal indicating selection of a specific refrigerant from the control interface of the refrigerator;
And a warning information providing unit that provides warning information to a control interface of the refrigerator, when the signal indicating the selection of the specific refrigerant indicates the selection of a refrigerant other than the refrigerant compatible with the refrigerator. Item 5. The control device according to item 4 or 5.   The control device according to claim 2, wherein the refrigerator is a transport refrigerator. The expansion valve control unit
The current degree of superheat is determined by subtracting the gas side saturation temperature of the refrigerant from the acquired outlet temperature,
The control device according to claim 2, wherein an expansion valve opening degree of an electronic expansion valve in the refrigerator is controlled so that the current superheat degree approaches the predetermined superheat degree.   The control device according to claim 2, wherein at least one of the refrigerants corresponding to the plurality of saturation temperature tables is a refrigerant having a temperature glide characteristic. A refrigerator operating according to different refrigerants,
Electronic expansion valve which can freely change the degree of expansion valve opening,
An evaporator for evaporating the refrigerant expanded by the electronic expansion valve;
A pressure sensor for detecting the pressure of the refrigerant at the outlet of the evaporator;
A temperature sensor for detecting the temperature of the refrigerant at the outlet of the evaporator;
And a control unit that controls the degree of opening of the expansion valve.
The electronic expansion such that the control unit can obtain a predetermined degree of superheat based on the gas-side saturation temperature of the refrigerant corresponding to the pressure detected by the pressure sensor and the temperature detected by the temperature sensor A refrigerator configured to control an expansion valve opening degree of a valve. A method of controlling a refrigerator according to different refrigerants, wherein
Obtaining the outlet pressure of the evaporator from a pressure sensor that detects the pressure of the refrigerant at the outlet of the evaporator in the refrigerator;
Obtaining the outlet temperature of the evaporator from a temperature sensor that detects the temperature of the refrigerant at the outlet of the evaporator;
The expansion valve opening degree of the electronic expansion valve in the refrigerator is controlled to obtain a predetermined degree of superheat based on the refrigerant gas side saturation temperature corresponding to the acquired outlet pressure and the acquired outlet temperature. And a controlling method.   A program for causing a computer of a refrigerator to execute the method according to claim 11.

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