Refrigeration device, environment forming device, and refrigeration method

Abstract

The invention provides a refrigeration device, an environment forming device and a refrigeration method. This refrigeration device is provided with: a refrigeration circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a flow control valve are arranged in this order, and which circulates a refrigerant; a valve control unit that controls the expansion valve and the flow control valve; and a target value changing unit for changing the target value of the evaporation temperature or the evaporation pressure in the evaporator. The valve control unit controls one of the expansion valve and the flow rate control valve on the basis of the target value changed by the target value changing unit, and controls the other of the expansion valve and the flow rate control valve in accordance with the cooling demand degree or the temperature of the object to be cooled. Therefore, frosting in the evaporator can be suppressed, and more flexible operation can be performed.

Description

Technical Field

[0001] The present invention relates to a refrigeration device, an environment forming device, and a refrigeration method. Background Art

[0002] Conventionally, as disclosed in Japanese Patent Laid-Open Publication No. Hei 2-97865, a refrigeration device is known in which a pressure regulating valve is provided on the downstream side of an evaporator in a refrigeration circuit. The pressure regulating valve is a spring-type pressure regulating valve. By using the pressure regulating valve, the refrigerant pressure in the evaporator can be maintained at a specified value or more. Accordingly, it is possible to suppress icing (frosting) on the fin portion of the evaporator.

[0003] The pressure regulating valve disclosed in Japanese Patent Laid-Open Publication No. Hei 2-97865 is spring-type and is provided to maintain the refrigerant pressure in the evaporator at a specified value or more. By providing this spring-type pressure regulating valve on the downstream side of the evaporator, frosting in the evaporator can be suppressed. On the other hand, since the refrigerant pressure in the evaporator is fixed at a specified value or more by using the pressure regulating valve, there is a problem that the refrigeration device disclosed in Japanese Patent Laid-Open Publication No. Hei 2-97865 cannot be operated flexibly. For example, when the temperature of the indoor air flowing through the evaporator is high, the frosting problem hardly occurs, and therefore, it is not necessary to maintain the refrigerant pressure in the evaporator at a specified value or more. Summary of the Invention

[0004] An object of the present invention is to provide a refrigeration device, an environment forming device, and a refrigeration method that can suppress frosting in an evaporator and can be operated more flexibly.

[0005] A refrigeration device according to one aspect of the present invention includes: a refrigeration circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a flow rate regulating valve are sequentially arranged and in which a refrigerant circulates; a valve control unit configured to control the expansion valve and the flow rate regulating valve; and a target value changing unit for changing a target value of an evaporation temperature or an evaporation pressure in the evaporator. The valve control unit controls one of the expansion valve and the flow rate regulating valve based on the target value changed by the target value changing unit, and controls the other of the expansion valve and the flow rate regulating valve according to a refrigeration requirement degree or a temperature of a cooling object.

[0006] An environment forming device according to another aspect of the present invention includes: an environment chamber; and the refrigeration device for cooling the inside of the environment chamber.

[0007] Another aspect of the present invention relates to a refrigeration method using a refrigeration device, the refrigeration device including: a refrigeration circuit configured with a compressor, a condenser, an expansion valve, an evaporator, and a flow rate regulating valve in sequence, and circulating a refrigerant, the refrigeration method performing the following steps: changing a target value of an evaporation temperature or an evaporation pressure in the evaporator; controlling one of the expansion valve and the flow rate regulating valve based on the changed target value; receiving, by a reception unit of the refrigeration device, information indicating a refrigeration requirement degree or a temperature of a cooling object; and controlling the other of the expansion valve and the flow rate regulating valve according to the refrigeration requirement degree or the temperature of the cooling object indicated by the information received by the reception unit.

[0008] According to the present invention, frosting in the evaporator can be suppressed, and more flexible operation can be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram showing the configuration of the refrigeration device according to the first embodiment.

[0010] Figure 2 It is a schematic diagram showing a control device including the controller of the refrigeration device.

[0011] Figure 3 It is a graph for explaining the relationship between the temperature in the storage and the target value of the evaporation temperature.

[0012] Figure 4 It is a graph for explaining the relationship between the refrigeration requirement degree and the opening degree of the flow rate regulating valve.

[0013] Figure 5 It is a graph for explaining the control flow of the refrigeration device.

[0014] Figure 6 It is a schematic diagram showing the configuration of the refrigeration device according to the third embodiment.

[0015] Figure 7 It is a schematic diagram showing the configuration of the refrigeration device according to a modification of the third embodiment.

[0016] Figure 8 It is a schematic diagram showing the configuration of the refrigeration device according to a modification of the third embodiment.

[0017] Figure 9 It is a schematic diagram showing the configuration of the refrigeration device according to the fifth embodiment.

[0018] Figure 10 It is a graph for explaining the relationship between the refrigeration requirement degree and the target value of the suction pressure.

[0019] Figure 11It is a schematic diagram showing the environment forming device according to the sixth embodiment.

[0020] Figure 12 It is a schematic diagram showing the configuration of the refrigeration device according to other embodiments. Detailed Embodiments

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0022] (First Embodiment)

[0023] As Figure 1 shown, the refrigeration device 10 according to the first embodiment includes a refrigeration circuit 15 filled with a refrigerant. The refrigerant can be a low-boiling refrigerant such as R-404A. Therefore, the evaporation temperature can be reduced to about -40°C, for example.

[0024] In the refrigeration circuit 15, a compressor 1, a condenser 2, an expansion valve 3, an evaporator 4, and a flow regulating valve 22 are sequentially provided. By the operation of the compressor 1, the refrigerant circulates in the refrigeration circuit 15, thereby performing a vapor compression refrigeration cycle. The refrigeration device 10 can be used to cool the indoor air of a freezer and / or a refrigerator, or can also be used to generate cooling water in a chiller. Alternatively, the refrigeration device 10 can also be used in an environment forming device such as an environmental test device that provides an environment with a specified temperature and / or humidity. Alternatively, the refrigeration device 10 can also be used in an air conditioner that adjusts the temperature and / or humidity of the interior of a house or the like. In addition, in the present embodiment, the refrigeration device 10 is used in a refrigerated freezer.

[0025] The compressor 1 is responsible for the compression step of the refrigeration cycle and is configured to suck and compress the refrigerant. The compressor 1 includes, for example, a reciprocating, scroll, or screw compression mechanism and is configured to drive the compression mechanism by a motor with a constant rotational speed. In addition, the compressor 1 can also be configured to be able to adjust the rotational speed of the motor using an inverter. Furthermore, the compressor 1 can also be a structure including a single unit compressor, and instead, it can also be a structure including two unit compressors with different capacities connected in parallel.

[0026] The condenser 2 is responsible for the condensation step of the refrigeration cycle and is configured to exchange heat between the refrigerant ejected from the compressor 1 and a cooling medium such as air, water, or refrigerant to condense the refrigerant.

[0027] The expansion valve 3 is responsible for the expansion step of the refrigeration cycle and is configured to expand the liquid refrigerant condensed in the condenser 2. The expansion valve 3 is formed by an electronic expansion valve, for example. Therefore, by adjusting the valve opening, it is possible to change the temperature of the refrigerant flowing through the evaporator 4 in the refrigeration circuit 15, that is, the evaporation temperature, and the pressure of the refrigerant in the evaporator 4, that is, the evaporation pressure.

[0028] The evaporator 4 is responsible for the evaporation step of the refrigeration cycle, and is configured such that the liquid refrigerant decompressed by the expansion valve 3 exchanges heat with air to evaporate the liquid refrigerant. The evaporator 4 cools the air (cooling object) supplied into the refrigerating and freezing compartment (cooled chamber). In addition, when the refrigeration device 10 is provided in a refrigerator that generates cooling water, the evaporator 4 is configured to evaporate the liquid refrigerant to cool the cooling water (cooling object).

[0029] The flow rate regulating valve 22 is provided to regulate the flow rate of the refrigerant flowing through the evaporator 4. The flow rate regulating valve 22 is formed of, for example, an electronic expansion valve. In addition, when the opening degree of the flow rate regulating valve 22 is adjusted, the low pressure in the refrigeration cycle and the pressure of the refrigerant flowing through the evaporator 4 also change.

[0030] An evaporation temperature detector 21 is provided in the refrigeration circuit 15. The evaporation temperature detector 21 is a detector for detecting the temperature of the refrigerant in the evaporator 4, that is, the evaporation temperature of the refrigerant in the evaporation step of the refrigeration cycle or a temperature equivalent thereto. Therefore, the evaporation temperature detector 21 can be disposed at a position between the expansion valve 3 and the evaporator 4 in the refrigeration circuit 15, or can be configured to detect the temperature of the refrigerant in the evaporator 4. The evaporation temperature detector 21 outputs a signal indicating the detected temperature.

[0031] The signal output by the evaporation temperature detector 21 is input to the controller 100. The controller 100 is formed of a microcomputer including a CPU that executes arithmetic processing, a ROM that stores processing programs and data, and a RAM that temporarily stores data. By executing the processing program stored in the controller 100, as Figure 2 shown, the controller 100 can function as a reception unit 101, a target value change unit 102, and a valve control unit 103.

[0032] The reception unit 101 is configured to repeatedly receive the refrigeration requirement degree at each specified time and temporarily store the received refrigeration requirement degree. The refrigeration requirement degree is generated by a generator 120, and the refrigeration requirement degree generated by the generator 120 is input to the reception unit 101. That is, the reception unit 101 receives information indicating the refrigeration requirement degree. In addition, in the illustrated example, an example in which the generator 120 and the controller 100 are independently configured is shown. However, the generator 120 for generating the refrigeration requirement degree may also be a function of the controller 100.

[0033] The generator 120 repeatedly receives signals from, for example, a sensor 121 that detects the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage or the temperature of the room to be cooled), an input device 122 that inputs a set value of the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage or the temperature of the room to be cooled), etc. at each specified time, and calculates the refrigeration requirement degree each time. The refrigeration requirement degree is a value obtained by dimensionlessizing the refrigeration load inside the refrigerated and frozen storage, that is, the object to be cooled. For example, it is calculated based on the difference between the detected value of the temperature of the object to be cooled (the detected temperature of the sensor 121) and the set value. Therefore, the greater the difference between the detected value of the temperature of the object to be cooled and the set value of the temperature of the object to be cooled, the greater the refrigeration requirement degree. Since the refrigeration requirement degree may change at any time, the generator 120 outputs the refrigeration requirement degree at each specified time. In addition, the information indicating the detected temperature output by the sensor 121 is received by the receiving unit 101.

[0034] The target value changing unit 102 is configured to store the target value of the evaporation temperature. In addition, the target value changing unit 102 is configured to change the stored target value according to the refrigeration requirement degree received by the receiving unit 101 and the detected temperature of the sensor 121, that is, the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage or the temperature of the room to be cooled). When the target value changing unit 102 sets the target value of the evaporation temperature when the received refrigeration requirement degree is the first refrigeration requirement degree to the first value, when the received refrigeration requirement degree is a refrigeration requirement degree less than the first refrigeration requirement degree, that is, the second refrigeration requirement degree, the target value of the evaporation temperature is changed to a second value lower than the first value. In addition, in the low-temperature region described later, when the target value changing unit 102 sets the target value of the evaporation temperature when the temperature of the object to be cooled is the first temperature to the first value, when the temperature of the object to be cooled is a temperature lower than the first temperature, that is, the second temperature, the target value of the evaporation temperature is changed to a second value lower than the first value. In addition, in the high-temperature region described later, regardless of the temperature of the object to be cooled, the target value of the evaporation temperature is set to the same value. The changed target value and the set target value are stored in the target value changing unit 102.

[0035] As Figure 3As shown, the target value of the evaporation temperature includes a low-temperature region that varies according to the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage or the temperature of the chamber to be cooled) and a high-temperature region that is constant regardless of the temperature of the object to be cooled. The boundary between the low-temperature region and the high-temperature region, that is, the threshold temperature TS, is set, for example, to a temperature of 0°C or higher and 60°C or lower, or 10°C or higher and 50°C or lower, or 20°C or higher and 40°C or lower. In the low-temperature region, the target value of the evaporation temperature is set to decrease as the temperature of the object to be cooled decreases. On the other hand, in the high-temperature region, the target value of the evaporation temperature is set to be the same regardless of the temperature of the object to be cooled.

[0036] In addition, the target value of the evaporation temperature may not be set in this way. For example, it may be set such that in the entire temperature range that the temperature of the object to be cooled can take, the target value of the evaporation temperature increases as the temperature of the object to be cooled increases. Specifically, in the low-temperature region (the region where the temperature inside the storage or the temperature of the chamber to be cooled is lower than the threshold temperature TS), as Figure 3 shown, the target value of the evaporation temperature may change linearly with the change in the temperature of the object to be cooled (the temperature inside the storage or the temperature of the chamber to be cooled), but instead, it may change curvilinearly, or it may also change stepwise (in a stepped manner). In addition, as Figure 3 shown, the change pattern of the target value of the evaporation temperature does not need to be set to be different in the low-temperature region and the high-temperature region. For example, in the entire region of the temperature of the object to be cooled, the target value of the evaporation temperature may change with the change in the temperature of the object to be cooled. In this case, it may change linearly, curvilinearly, or stepwise (in a stepped manner). At this time, when the target value changing unit 102 sets the target value of the evaporation temperature when the temperature of the object to be cooled is the first temperature to the first value, when the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage) is a temperature lower than the first temperature, that is, the second temperature, the target value of the evaporation temperature is changed to the second value lower than the first value. In addition, when the refrigeration device 10 is configured as a refrigerating machine, the temperature of the object to be cooled is the temperature of the cooling water introduced into the evaporator 4.

[0037] The target value of the evaporation temperature can have a range relative to the temperature of the object to be cooled (the temperature inside the storage or the temperature of the chamber to be cooled). For example, the target value of the evaporation temperature is not only changed according to the temperature of the object to be cooled, but can also be changed according to the degree of refrigeration requirement. That is, even when the temperature of the object to be cooled is at a certain temperature, the target value of the evaporation temperature can still be changed according to the degree of refrigeration requirement. In this case, it is set that the greater the degree of refrigeration requirement, the higher the target value of the evaporation temperature, and the smaller the degree of refrigeration requirement, the lower the target value of the evaporation temperature. The upper limit value and the lower limit value of the target value of the evaporation temperature in this case can include a low-temperature region that changes according to the temperature of the object to be cooled and a region with a temperature higher than the low-temperature region, that is, a region that is constant regardless of the temperature of the object to be cooled, but is not limited thereto. It can also be set that in the entire temperature range that the temperature of the object to be cooled can take, the upper limit value and the lower limit value of the target value of the evaporation temperature increase as the temperature of the object to be cooled increases.

[0038] The valve control unit 103 is configured to control the expansion valve 3 based on the target value of the evaporation temperature changed by the target value changing unit 102, and to control the flow rate regulating valve 22 according to the degree of refrigeration requirement.

[0039] The control of the expansion valve 3 is performed whenever the target value of the evaporation temperature is adjusted. The target value of the evaporation temperature is set by the target value changing unit 102 to a value corresponding to the detected temperature of the sensor 121, that is, the temperature of the object to be cooled (for example, the temperature inside the storage or the temperature of the chamber to be cooled). Then, the valve control unit 103 controls the expansion valve 3 so that the detected temperature of the evaporation temperature detector 21 approaches the target value of the evaporation temperature set by the target value changing unit 102. If the target value of the evaporation temperature is low, the opening degree of the expansion valve 3 is reduced, and if the target value of the evaporation temperature is high, the opening degree of the expansion valve 3 is increased.

[0040] In addition, whenever the reception unit 101 receives the degree of refrigeration requirement, the valve control unit 103 adjusts the opening degree of the flow rate regulating valve 22 according to the received degree of refrigeration requirement. That is, information indicating the relationship between the degree of refrigeration requirement and the opening degree of the flow rate regulating valve 22 is stored in the controller 100, and the valve control unit 103 uses this information to control the flow rate regulating valve 22.

[0041] In addition, in the controller 100, information representing the relationship between the degree of refrigeration requirement and the opening degree of the flow control valve 22 may not be stored, but information representing the relationship between the degree of refrigeration requirement and the suction pressure may be stored. In this case, the valve control unit 103 controls the flow control valve 22 using this information. However, in this case, the point of controlling the flow control valve 22 based on the degree of refrigeration requirement does not change. For example, when the degree of refrigeration requirement is large, the suction pressure is set to a high value. In this case, the flow control valve 22 is controlled to increase the opening degree. In addition, when the degree of refrigeration requirement is small, the suction pressure is set to a low value. In this case, the flow control valve 22 is controlled to decrease the opening degree.

[0042] As Figure 4 shown, the flow control valve 22 is controlled to increase the opening degree if the degree of refrigeration requirement is large, and to decrease the opening degree if the degree of refrigeration requirement is small. In addition, the flow control valve 22 may maintain the opening degree at a constant value in the range where the degree of refrigeration requirement is above a specified value or below a specified value, or in both of these ranges.

[0043] When the temperature of the object to be cooled (e.g., the temperature in the storage or the temperature of the room to be cooled) is lower than the threshold temperature TS, the lower the temperature of the object to be cooled, the lower the target value of the evaporation temperature is set. Therefore, the valve control unit 103 controls the expansion valve 3 so that the lower the temperature of the object to be cooled, the further the opening degree of the expansion valve 3 decreases. In addition, at this time, the valve control unit 103 controls the flow control valve 22 to the opening degree based on the degree of refrigeration requirement. That is, the flow control valve 22 is not controlled based on the evaporation temperature (evaporation pressure). In addition, when the temperature of the object to be cooled is lower than the threshold temperature TS, the higher the temperature of the object to be cooled, the higher the target value of the evaporation temperature is set (refer to Figure 3 ). Therefore, the valve control unit 103 controls the expansion valve 3 so that the higher the temperature of the object to be cooled, the further the opening degree of the expansion valve 3 increases. In this case, the valve control unit 103 also controls the flow control valve 22 to the opening degree based on the degree of refrigeration requirement.

[0044] On the other hand, when the temperature of the object to be cooled (e.g., the temperature in the storage or the temperature of the room to be cooled) is higher than the threshold temperature TS, the target value of the evaporation temperature is set to a constant value regardless of the temperature of the object to be cooled. Therefore, the valve control unit 103 controls the expansion valve 3 to reach the target value of the set evaporation temperature. In addition, in this case, the valve control unit 103 also adjusts the opening degree of the flow control valve 22 based on the degree of refrigeration requirement. That is, the flow control valve 22 is controlled so that the smaller the degree of refrigeration requirement, the further the opening degree decreases, and the larger the degree of refrigeration requirement, the further the opening degree increases. Therefore, the evaporation temperature can be maintained at a high value and the refrigeration capacity can be made variable.

[0045] Here, a refrigeration method using the refrigeration device 10 having the above-described configuration will be described.

[0046] After the target temperature of the temperature inside the storage or the temperature of the chamber to be cooled is set and the operation of the refrigeration device 10 is started, as Figure 5 shown, the controller 100 receives the refrigeration requirement degree generated by the generator 120 and the detected temperature of the sensor 121 (the temperature of the object to be cooled) (ST11, ST12). The refrigeration requirement degree and the detected temperature of the sensor 121 are repeatedly received by the controller 100 at each specified time.

[0047] Next, the target value changing unit 102 of the controller 100 changes the target value of the evaporation temperature based on the refrigeration requirement degree received by the receiving unit 101 and the detected temperature of the sensor 121 (step ST13).

[0048] At this time, when the detected temperature of the sensor 121 is in the low-temperature region below the preset threshold temperature ST, the target value changing unit 102 sets a low target value as the target value of the evaporation temperature as the received detected temperature becomes lower. On the other hand, as the received detected temperature of the sensor 121 becomes higher, a high target value is set as the target value of the evaporation temperature. That is, in the low-temperature region, even with the same refrigeration requirement degree, the lower the detected temperature, the lower the target value of the evaporation temperature is set.

[0049] In addition, when the detected temperature of the sensor 121 is in the high-temperature region higher than the preset threshold temperature ST, the target value changing unit 102 sets the target value of the evaporation temperature to a constant value regardless of the detected temperature of the sensor 121.

[0050] Next, the valve control unit 103 controls the expansion valve 3 based on the target value of the evaporation temperature changed by the target value changing unit 102, and controls the flow rate regulating valve 22 according to the refrigeration requirement degree (step ST14).

[0051] Specifically, the valve control unit 103 controls the expansion valve 3 in such a manner that the opening degree of the flow rate regulating valve 22 is set to a specified opening degree corresponding to the refrigeration requirement degree (for example, if the refrigeration requirement degree is 100, it is the maximum opening degree). In this state, the detected temperature of the evaporation temperature detector 21 is made to approach the target value of the evaporation temperature set by the target value changing unit 102. At this time, the lower the target value of the evaporation temperature, the smaller the opening degree of the expansion valve 3, and the higher the target value of the evaporation temperature, the larger the opening degree of the expansion valve 3.

[0052] Next, if the required refrigeration degree received by the acceptance unit 101 changes from the previously received required refrigeration degree, the valve control unit 103 adjusts the opening degree of the flow control valve 22 according to the change amount of the required refrigeration degree. Since the evaporation temperature changes accordingly, the valve control unit 103 further adjusts the opening degree of the expansion valve 3 so that the evaporation temperature approaches the target value.

[0053] For example, when the required refrigeration degree is less than the previous value, the valve control unit 103 further reduces the opening degree of the flow control valve 22. Since the evaporation temperature rises accordingly, the valve control unit 103 reduces the opening degree of the expansion valve 3 as the evaporation temperature changes. Accordingly, the evaporation temperature approaches the target value. At this time, by reducing the opening degrees of the expansion valve 3 and the flow control valve 22, the flow rate of the evaporator 4 decreases and the refrigeration capacity decreases.

[0054] At this time, if it is a low-temperature region below the threshold temperature TS, the lower the detected temperature, the lower the target value of the evaporation temperature is adjusted. Therefore, even when the temperature of the object to be cooled is low and the temperature of the air returning to the evaporator 4 is low, the refrigerant can be easily evaporated. In addition, since the opening degrees of both the expansion valve 3 and the flow control valve 22 are reduced, the flow rate of the refrigerant flowing through the evaporator 4 decreases, which helps to reduce the power of the compressor 1.

[0055] On the other hand, if the state of the required refrigeration degree is still high, the opening degree of the flow control valve 22 is maintained in a large state. In addition, since the target value of the evaporation temperature is also maintained at a high value, the opening degree of the expansion valve 3 is maintained in a large state. Therefore, the flow rate of the refrigerant flowing through the evaporator 4 is ensured in a state where the evaporation temperature is high, and the state of exerting a large refrigeration capacity is maintained. Therefore, the refrigeration capacity corresponding to the high required refrigeration degree can be exerted.

[0056] In addition, when the required refrigeration degree is greater than the previous value, the valve control unit 103 further increases the opening degree of the flow control valve 22. Since the evaporation temperature drops accordingly, the valve control unit 103 increases the opening degree of the expansion valve 3 as the evaporation temperature changes. Accordingly, the evaporation temperature approaches the target value. At this time, by increasing the opening degrees of the expansion valve 3 and the flow control valve 22, the flow rate of the evaporator 4 increases and the refrigeration capacity rises.

[0057] As described above, in the present embodiment, the valve control unit 103 controls the expansion valve 3 based on the target value of the evaporation temperature in the evaporator 4. At this time, the following trend is shown: as the opening degree is reduced in such a way that the opening degree of the flow rate regulating valve 22 is reduced, the evaporation temperature (or evaporation pressure) in the evaporator 4 becomes higher. Therefore, compared with the refrigeration circuit without the flow rate regulating valve 22, the evaporation temperature (or evaporation pressure) can be increased. Accordingly, even when the temperature of the object to be cooled is lower, for example, a state where no frost forms or a state where it is difficult for frost to form in the evaporator 4 can be achieved. In other words, the refrigeration device 10 can be controlled in such a way that the temperature of the object to be cooled is further reduced. In addition, in the refrigeration circuit 15, the pressure reduction degree corresponding to the pressure difference between the high pressure and the low pressure of the refrigeration circuit 15 obtained by the compressor 1 is obtained through the expansion valve 3 and the flow rate regulating valve 22.

[0058] In addition, since the target value of the evaporation temperature can be changed by the target value changing unit 102, more flexible operation can be performed compared with the case where the target value of the evaporation temperature is fixed. For example, if the target value of the evaporation temperature is changed to a higher value, the opening degree of the expansion valve 3 is controlled to be further increased. At this time, the opening degree of the flow rate regulating valve 22 is controlled according to the refrigeration requirement degree, and therefore, the evaporation temperature changes according to the change amount of the opening degree of the flow rate regulating valve 22. Therefore, according to the changed evaporation temperature, the opening degree of the expansion valve 3 is further adjusted, and thus, the change of the evaporation temperature can be suppressed. Therefore, the evaporation temperature can be adjusted to the target value by using the expansion valve 3 and the flow rate regulating valve 22, and the required refrigeration capacity corresponding to the refrigeration requirement degree can be exerted. Accordingly, the variable range of the refrigeration capacity can be expanded while suppressing frosting, and it is also possible to contribute to the continuous operation and energy saving of the device. In addition, the refrigeration device 10 may be configured as an air conditioner capable of adjusting humidity. In this case, control can be performed at an evaporation temperature (refrigerant temperature in the evaporator 4) suitable for the dew point temperature. Therefore, wide-range temperature and humidity operation can be performed. In addition, since the sensible heat ratio can be changed based on the evaporation temperature, the required dehumidifying capacity can be exerted, and it is also possible to contribute to energy saving.

[0059] In addition, the valve control unit 103 is configured to control the flow control valve 22 according to the refrigeration demand degree. Instead, it may also be configured to control the flow control valve 22 according to the temperature of the object to be cooled. For example, when the temperature of the object to be cooled (the temperature in the storage or the temperature of the chamber to be cooled) is lower than the freezing point, the valve control unit 103 may also increase the opening degree of the flow control valve 22 so that the evaporation temperature decreases below the freezing point. In addition, when the temperature of the object to be cooled is higher than the freezing point, in order to make the evaporation temperature higher than the freezing point, the valve control unit 103 may control the flow control valve 22 in such a way that the opening degree is reduced. In this case, since the evaporation pressure in the evaporator 4 increases and the evaporation temperature rises, frosting can be prevented. In addition, according to the temperature of the object to be cooled, the opening degree adjustment of the flow control valve 22 may be opposite to the above situation.

[0060] (Second Embodiment)

[0061] In the first embodiment, the valve control unit 103 controls the expansion valve 3 based on the target value of the evaporation temperature and controls the flow control valve 22 according to the refrigeration demand degree. In contrast, in the second embodiment, the valve control unit 103 is configured to control the flow control valve 22 based on the target value of the evaporation temperature changed by the target value changing unit 102 and control the expansion valve 3 according to the refrigeration demand degree.

[0062] The valve control unit 103 sets the opening degree of the expansion valve 3 to a specified opening degree corresponding to the refrigeration demand degree (for example, if the refrigeration demand degree is 100, it is the maximum opening degree) in step ST14. In addition, the valve control unit 103 controls the flow control valve 22 in this state so that the detected temperature of the evaporation temperature detector 21 approaches the target value of the evaporation temperature set by the target value changing unit 102. At this time, if the target value of the evaporation temperature is lower than the current evaporation temperature, the opening degree of the flow control valve 22 increases, and if the target value of the evaporation temperature is higher than the current evaporation temperature, the opening degree of the flow control valve 22 decreases.

[0063] Next, if the refrigeration demand degree received by the reception unit 101 changes from the previously received refrigeration demand degree, the valve control unit 1 03 adjusts the opening degree of the expansion valve 3 according to the change amount of the refrigeration demand degree. Since the evaporation temperature changes accordingly, the valve control unit 103 further adjusts the opening degree of the flow control valve 22 so that the evaporation temperature approaches the target value.

[0064] For example, when the required refrigeration degree is less than the previous value, the valve control unit 103 reduces the opening degree of the expansion valve 3. Along with this, the evaporation temperature drops. If the target value of the evaporation temperature remains unchanged, the valve control unit 103 reduces the opening degree of the flow control valve 22 along with the change in the evaporation temperature. Accordingly, the evaporation temperature approaches the target value. At this time, due to the reduction in the opening degrees of the expansion valve 3 and the flow control valve 22, the flow rate of the evaporator 4 decreases and the refrigeration capacity reduces.

[0065] On the other hand, if the state of high required refrigeration degree still remains, the opening degree of the expansion valve 3 is maintained in a large state. In addition, since the target value of the evaporation temperature also remains high, the opening degree of the flow control valve 22 is maintained in a large state. Therefore, the flow rate of the refrigerant flowing through the evaporator 4 is ensured in the state of high evaporation temperature, and the state of exerting a large refrigeration capacity is maintained. Therefore, the refrigeration capacity corresponding to the high required refrigeration degree can be exerted.

[0066] In addition, when the required refrigeration degree is greater than the previous value, the valve control unit 103 further increases the opening degree of the expansion valve 3. Since the evaporation temperature rises along with this, the valve control unit 103 increases the opening degree of the flow control valve 22 along with the change in the evaporation temperature. Accordingly, the evaporation temperature approaches the target value. Therefore, since the flow rate of the refrigerant flowing through the evaporator 4 increases, a higher refrigeration capacity can be exerted.

[0067] In the present embodiment, for example, if the target value of the evaporation temperature is changed to a higher value, the opening degree of the flow control valve 22 is controlled to be further reduced. At this time, since the expansion valve 3 is controlled according to the required refrigeration degree, the evaporation temperature changes according to the change amount of the opening degree of the expansion valve 3. Therefore, according to the changed evaporation temperature, the opening degree of the flow control valve 22 is further adjusted, so that the change in the evaporation temperature can be suppressed. Therefore, the evaporation temperature can be adjusted to the target value by using the expansion valve 3 and the flow control valve 22, and the required refrigeration capacity corresponding to the required refrigeration degree can be exerted. Accordingly, the variable range of the refrigeration capacity can be expanded while suppressing frosting, which can also contribute to the continuous operation and energy saving of the device. In addition, the refrigeration device 10 can be configured as an air conditioner capable of adjusting humidity. In this case, control can be performed at an evaporation temperature (refrigerant temperature in the evaporator 4) suitable for the dew point temperature, so that wide-range temperature and humidity operation can be performed. In addition, since the sensible heat ratio can be changed based on the evaporation temperature, the required dehumidification capacity can be exerted, which can also contribute to energy saving.

[0068] In addition, the valve control unit 103 may also be configured to control the expansion valve 3 not according to the refrigeration requirement degree but according to the temperature of the object to be cooled. When the valve control unit 103 controls the expansion valve 3 according to the temperature of the object to be cooled, the expansion valve 3 is controlled such that the opening degree increases if the temperature of the object to be cooled is high, and the opening degree decreases if the temperature of the object to be cooled is low. That is, by controlling the expansion valve 3 in such a way that the opening degree of the expansion valve 3 increases when the temperature of the object to be cooled is high, the evaporation temperature in the evaporator 4 rises. On the other hand, by controlling the expansion valve 3 in such a way that the opening degree of the expansion valve 3 decreases when the temperature of the object to be cooled is low, the evaporation temperature in the evaporator 4 decreases. Therefore, the object to be cooled can be cooled efficiently.

[0069] In addition, the description of other structures, operations, and effects is omitted, and the description of the first embodiment can be cited for the second embodiment.

[0070] (Third Embodiment)

[0071] In the first embodiment and the second embodiment, the target value changing unit 102 is configured to change the target value of the evaporation temperature. In contrast, in the third embodiment, the target value changing unit 102 is configured to change the target value of the evaporation pressure.

[0072] As Figure 6 shown, in the third embodiment, an evaporation pressure detector 33 is provided instead of the evaporation temperature detector 21. The evaporation pressure detector 33 is disposed at a position between the expansion valve 3 and the evaporator 4 in the refrigeration circuit 15, and detects the evaporation pressure of the refrigerant in the evaporator 4.

[0073] In addition, as Figure 7 shown, an evaporation pressure detector 32 disposed at a position between the evaporator 4 and the flow rate regulating valve 22 in the refrigeration circuit 15 may be provided instead of the evaporation pressure detector 33. In addition, both the evaporation pressure detector 33 (see Figure 6 ) and the evaporation pressure detector 32 may be provided, or the evaporation temperature detector 21 (see Figure 1 ) and the evaporation pressure detector 32 may be provided. In the refrigeration circuit 15, there is a pressure difference corresponding to the pressure loss in the evaporator 4 at the position between the expansion valve 3 and the flow rate regulating valve 22, but by considering this pressure difference, the evaporation pressure detector 32 can be used to detect the refrigerant pressure (evaporation pressure) in the evaporator 4.

[0074] When the evaporation pressure detector 33 or the evaporation pressure detector 32 is provided, Figure 3The target value of the evaporation temperature shown can be replaced with the target value of the evaporation pressure. The target value changing unit 102 sets the target value of the evaporation pressure when the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage or the temperature of the chamber to be cooled) is the first temperature as the first value. On the other hand, when the temperature of the object to be cooled (the temperature inside the refrigerated and frozen storage or the temperature of the chamber to be cooled) is a temperature lower than the first temperature, that is, the second temperature, the target value of the evaporation pressure is set as the second value lower than the first value. In addition, the target value changing unit 102 may be configured to set a range for the target value of the evaporation pressure and change the target value of the evaporation pressure according to the received refrigeration requirement degree.

[0075] In this case, the valve control unit 103 is configured to control the expansion valve 3 based on the target value of the evaporation pressure changed by the target value changing unit 102, and control the flow regulating valve 22 according to the refrigeration requirement degree. Or, the valve control unit 103 is configured to control the flow regulating valve 22 based on the target value of the evaporation pressure changed by the target value changing unit 102, and control the expansion valve 3 according to the refrigeration requirement degree. In addition, the controller 100 may also derive the temperature equivalent to the pressure of the evaporation pressure detector 32 to be used as the evaporation temperature.

[0076] In addition, as Figure 8 shown, a temperature detector 34 may be used instead of the evaporation pressure detector 32. The temperature detector 34 is disposed in a bypass flow path 16 connected to the refrigeration circuit 15. In this case, one end of the bypass flow path 16 is connected between the condenser 2 and the expansion valve 3 in the refrigeration circuit 15, and the other end is connected between the evaporator 4 and the flow regulating valve 22 in the refrigeration circuit 15. An electronic expansion valve 11 is provided in the bypass flow path 16, and the temperature detector 34 is disposed at a position downstream of the electronic expansion valve 11 where the temperature of the evaporation process can be detected. In the bypass flow path 16, the temperature on the downstream side of the electronic expansion valve 11 becomes the evaporation temperature equivalent to the outlet pressure of the evaporator 4, so that the evaporation temperature that can predict the pressure loss of the evaporator 4 can be measured.

[0077] The description of other structures, operations, and effects is omitted, and the descriptions of the first and second embodiments can be cited for the third embodiment.

[0078] (Fourth Embodiment)

[0079] In the first embodiment, the valve control unit 103 always controls the flow control valve 22 according to the refrigeration requirement degree. In contrast, in the fourth embodiment, the valve control unit 103 has a first control mode of controlling the flow control valve 22 according to the refrigeration requirement degree and a second control mode of maintaining the flow control valve 22 fully open. The first control mode is executed when the temperature of the object to be cooled (the temperature in the storage or the temperature of the chamber to be cooled) is above the specified temperature. If the temperature of the object to be cooled decreases and becomes lower than the specified temperature, the control mode is switched to the second control mode. That is, in the second control mode, since the flow control valve 22 is maintained fully open, the evaporation temperature decreases compared with the first control mode. Therefore, the second control mode is executed when the temperature of the object to be cooled becomes a low temperature below the freezing point or when it is desired to increase the refrigeration capacity. On the other hand, the first control mode is executed to suppress frosting as in the first embodiment. The specified temperature for switching between the first control mode and the second control mode is set to a value lower than 10°C, for example, 0°C or 5°C. In addition, the second control mode is not limited to being executed when the temperature of the object to be cooled is lower than the specified temperature, and it may also be executed when the temperature of the object to be cooled is above the specified temperature and the evaporator 4 is in a condition where frosting is difficult. For example, the second control mode is executed when it is desired to rapidly change the temperature of the object to be cooled from a high temperature to a low temperature, or when it is desired to set a low humidity to exhibit the dehumidification ability during the temperature and humidity operation.

[0080] In the first control mode, the control described in step ST14 of the first embodiment is executed. On the other hand, in the second control mode, the flow control valve 22 is maintained fully open. Therefore, in the second control mode, the control of the flow control valve 22 based on the refrigeration requirement degree is not performed. However, in the second control mode, the expansion valve 3 is controlled so that the detected temperature of the evaporation temperature detector 21 reaches the target value of the evaporation temperature.

[0081] In addition, in the first control mode, instead of controlling the flow control valve 22, the expansion valve 3 may be controlled in the same manner as in the second embodiment (step ST14). Further, as in the third embodiment, the target value changing unit 102 may be configured to change the target value of the evaporation pressure, the valve control unit 103 may be configured to control the expansion valve 3 or the flow control valve 22 based on the target value of the evaporation pressure changed by the target value changing unit 102, and control the flow control valve 22 or the expansion valve 3 according to the refrigeration requirement degree. In this case, the Figure 6 shown evaporation pressure detector 33, Figure 7 shown evaporation pressure detector 32, or Figure 8 shown temperature detector 34 may be used.

[0082] The description of other structures, operations, and effects is omitted, and the descriptions of the first to third embodiments may be cited for the fourth embodiment.

[0083] (Fifth Embodiment)

[0084] In the first embodiment, the opening degree of the flow control valve 22 is set according to the refrigeration demand degree. In contrast, in the fifth embodiment, the target value of the suction pressure is set according to the refrigeration demand degree, and the flow control valve 22 is controlled so as to reach the target value of the suction pressure. Hereinafter, the same reference numerals are given to the same components as those in the first to fourth embodiments, and the detailed description thereof is omitted.

[0085] As Figure 9 shown, in the fifth embodiment, a pressure detector 31 for detecting the suction pressure of the compressor 1 is provided.

[0086] In the valve control unit 103, information showing the relationship in which the target value of the suction pressure is set according to the refrigeration demand degree as Figure 10 shown is used. That is, the higher the refrigeration demand degree, the higher the target value of the suction pressure, and the lower the refrigeration demand degree, the lower the target value of the suction pressure. The maximum value and the minimum value of the target value of the suction pressure are set based on the specifications of the compressor 1.

[0087] That is, the lower the target value of the evaporation temperature, the further the opening degree of the expansion valve 3 is reduced. In addition, if the refrigeration demand degree is low, the opening degree of the flow control valve 22 is also further reduced. Therefore, the suction pressure of the compressor 1 is reduced. However, the target value of the suction pressure set for the lowest value of the refrigeration demand degree, that is, the lowest value of the target values, is set based on the specifications of the compressor 1. Therefore, even when the refrigeration demand degree is the lowest, the compressor 1 can be stably operated.

[0088] The valve control unit 103 controls the flow control valve 22 so that the detection pressure of the pressure detector 31 reaches the target value of the suction pressure set according to the refrigeration demand degree. That is, in the present embodiment, the valve control unit 103 also controls the flow control valve 22 according to the refrigeration demand degree.

[0089] Therefore, according to the present embodiment, the expansion valve 3 is controlled so that the evaporation temperature in the evaporator 4 reaches the target value. On the other hand, the flow control valve 22 is controlled so that the detection value of the pressure detector 31 reaches the target value of the suction pressure set according to the refrigeration demand degree. Therefore, not only the evaporation temperature is adjusted to the target value, but also the suction pressure is adjusted to the target value. Therefore, it is possible to prevent the suction pressure from rising or falling excessively when the evaporation temperature is adjusted to the target value. Therefore, it contributes to the stable operation of the compressor 1.

[0090] In addition, in the present embodiment, the flow control valve 22 is controlled such that the evaporation temperature in the evaporator 4 reaches the target value. On the other hand, the expansion valve 3 is controlled such that the detected value of the pressure detector 31 reaches the suction pressure target value set according to the refrigeration requirement degree. The description of other structures, operations, and effects is omitted, and the descriptions of the first to fourth embodiments can be cited for the fifth embodiment.

[0091] (Sixth Embodiment)

[0092] Figure 11 This represents the sixth embodiment. Here, the same reference numerals are attached to the constituent elements that are the same as those in the first to fifth embodiments, and their detailed descriptions are omitted.

[0093] The sixth embodiment is an example in which the refrigeration device 10 is applied to an environmental forming device 50 such as an environmental test device. As Figure 11 shown, the environmental forming device 50 has an environmental chamber 51 and is configured to adjust the inside of the environmental chamber 51 to a specified temperature environment. The environmental forming device 50 further includes an air-conditioning chamber 52 for generating air with a regulated temperature, and the evaporator 4 of the refrigeration device 10 is disposed in the air-conditioning chamber 52.

[0094] In the air-conditioning chamber 52, a heater 54 for heating air and a blower 55 for blowing the air with a regulated temperature into the environmental chamber 51 are disposed on the downstream side of the evaporator 4. A sensor 121 for detecting the temperature of the object to be cooled (the indoor temperature of the environmental chamber 51) is provided in the environmental chamber 51. An inputter 122 is used to input the set temperature of the temperature in the environmental chamber 51. The environmental forming device 50 may also be a device that can set a wide range of temperatures such as a sub-zero temperature region, a normal temperature region, or a high temperature region, and has a program operation function that enables multiple temperatures to change stepwise or continuously.

[0095] In addition, the environmental forming device 50 may also be configured to obtain not only a specified temperature environment but also a specified humidity environment. In this case, a humidifier (not shown) is provided. In this case, the evaporator 4 can also function as a dehumidifier.

[0096] The generator 120 calculates the refrigeration requirement degree using the detected temperature of the sensor 121 and the set temperature from the inputter 122.

[0097] The output of the heater 54 is controlled based on the detected temperature of the sensor 121 and the set temperature from the input unit 122. That is, although the specified refrigerating capacity can be achieved by controlling the expansion valve 3 and the flow rate regulating valve 22 of the refrigerating device 10, the detected temperature of the sensor 121 is sometimes lower than the set temperature. Therefore, the indoor temperature of the environmental chamber 51 is finely adjusted by the heater 54. Thus, if the overcooling of the refrigerating device 10 can be suppressed, not only the power of the refrigerating device 10 but also the power of the heater 54 can be suppressed. In this regard, when the refrigeration requirement is small, the target value of the evaporation temperature is adjusted to a low value, so that the refrigerant circulation amount can be reduced by the expansion valve 3 and the flow rate regulating valve 22. Accordingly, the refrigerating capacity can be reduced. Therefore, the power of the heater 54 can also be suppressed, and further energy saving can be achieved. In addition, since the configuration is such that the target value changing unit 102 changes the target value of the evaporation temperature, the evaporation temperature can be set higher than the freezing point. In addition, since the flow rate regulating valve 22 is used to adjust the refrigerant flow rate flowing through the evaporator 4, energy saving is achieved while frost formation is suppressed. Especially in the case of continuous operation for adjusting humidity, it can greatly contribute to this effect. As described above, since the target value changing unit 102 changes the target value of the evaporation temperature and controls the flow rate regulating valve 22, both the followability to the set temperature and the energy saving after the temperature reaches the set temperature can be achieved, which is particularly suitable for the case of executing program operation.

[0098] In addition, the descriptions of other structures, operations, and effects are omitted, and the descriptions of the first to fifth embodiments can be cited for the sixth embodiment.

[0099] (Other Embodiments)

[0100] In addition, the embodiments disclosed this time are illustrative in all respects and should not be considered as restrictive. The present invention is not limited to the above-described embodiments, and various changes, improvements, etc. can be made without departing from the gist thereof. For example, as Figure 12 shown, a bypass flow path 18 bypassing the flow rate regulating valve 22 may be provided in the refrigeration circuit 15, and a solenoid valve 36 may be provided in the bypass flow path 18.

[0101] Furthermore, in the above-described embodiments, one expansion valve 3 and one flow rate regulating valve 22 are provided, but a plurality of expansion valves 3 and a plurality of flow rate regulating valves 22 may also be provided.

[0102] Here, the above-described embodiments are summarized.

[0103] (1) The refrigeration device according to the described embodiment includes: a refrigeration circuit configured with a compressor, a condenser, an expansion valve, an evaporator, and a flow rate regulating valve in sequence, and circulating a refrigerant; a valve control unit configured to control the expansion valve and the flow rate regulating valve; and a target value changing unit for changing the target value of the evaporation temperature or evaporation pressure in the evaporator. The valve control unit controls one of the expansion valve and the flow rate regulating valve based on the target value changed by the target value changing unit, and controls the other of the expansion valve and the flow rate regulating valve according to the refrigeration requirement degree or the temperature of the cooling object.

[0104] In the refrigeration device, the valve control unit controls one of the expansion valve and the flow rate regulating valve based on the target value of the evaporation temperature or evaporation pressure in the evaporator. At this time, as the flow rate regulating valve is reduced in such a manner that the opening degree of the flow rate regulating valve is decreased, the evaporation temperature or evaporation pressure in the evaporator has a tendency to increase. Therefore, compared with a refrigeration circuit without a flow rate regulating valve, the evaporation temperature (or evaporation pressure) can be increased. Accordingly, even in a case where, for example, control is performed in such a manner that the temperature of the cooling object is made lower, a state where frosting does not occur or a state where frosting is difficult to occur in the evaporator can be achieved. In other words, control can be performed in such a manner that the temperature of the cooling object is further decreased in a state where frosting is difficult to occur. In addition, in the refrigeration circuit, the degree of decompression corresponding to the pressure difference between the high pressure and the low pressure of the refrigeration circuit obtained by the compressor is obtained by the expansion valve and the flow rate regulating valve.

[0105] Furthermore, since the target value of the evaporation temperature or evaporation pressure can be changed by the target value changing unit, more flexible operation can be performed compared with a case where the target value of the evaporation temperature or evaporation pressure is fixed. For example, in a configuration where the expansion valve is controlled based on the evaporation temperature or evaporation pressure, for example, if the target value of the evaporation temperature or evaporation pressure is changed to a higher value, the opening degree of the expansion valve is controlled to be further increased. On the other hand, since the flow rate regulating valve is controlled according to the refrigeration requirement degree or the temperature of the cooling object, the evaporation temperature or evaporation pressure changes according to the change amount of the opening degree of the flow rate regulating valve. Therefore, according to the changed evaporation temperature or evaporation pressure, the opening degree of the expansion valve is further adjusted, and thus, the change of the evaporation temperature or evaporation pressure can be suppressed. Therefore, the evaporation temperature or evaporation pressure can be adjusted to the target value by the expansion valve and the flow rate regulating valve, and the required refrigeration capacity corresponding to the refrigeration requirement degree or the temperature of the cooling object can be exerted.

[0106] On the other hand, for example, in the case of a configuration that controls the flow control valve based on the evaporation temperature or evaporation pressure, if the target value of the evaporation temperature or evaporation pressure is changed to a higher value, the opening degree of the flow control valve is controlled to further decrease. At this time, the expansion valve is controlled according to the refrigeration requirement degree or the temperature of the cooling object. Therefore, the evaporation temperature or evaporation pressure changes according to the change amount of the opening degree of the expansion valve. Therefore, according to the changed evaporation temperature or evaporation pressure, the opening degree of the flow control valve is further adjusted, so that the change of the evaporation temperature or evaporation pressure can be suppressed. Therefore, the evaporation temperature or evaporation pressure can be adjusted to the target value by using the expansion valve and the flow control valve, and the required refrigeration capacity corresponding to the refrigeration requirement degree or the temperature of the cooling object can be exerted. In addition, since the sensible heat ratio can be changed based on the evaporation temperature (the temperature of the evaporator), for example, when adjusting the humidity of the air of the cooling object, the required dehumidification capacity can be exerted.

[0107] (2) The target value changing unit may also be configured to: when the temperature of the cooling object is the first temperature, set the target value to the first target value; when the temperature of the cooling object is the second temperature lower than the first temperature, set the target value to the second target value lower than the first target value.

[0108] In this technical solution, when the temperature of the cooling object is the second temperature lower than the first temperature, the target value of the evaporation temperature or evaporation pressure is set to the second target value lower than the first target value. Accordingly, when the temperature of the cooling object is the second temperature (lower temperature), in one of the expansion valve and the flow control valve, it is controlled that: if it is the expansion valve, the opening degree is further decreased, and if it is the flow control valve, the opening degree is further increased. And the other of the expansion valve and the flow control valve is controlled according to the refrigeration requirement degree or the temperature of the cooling object. Therefore, the evaporation temperature or evaporation pressure in the evaporator is adjusted according to the temperature of the cooling object, and the refrigeration capacity corresponding to the refrigeration requirement degree or the temperature of the cooling object is exerted. For example, when the temperature of the cooling object is higher, the target value of the evaporation temperature or evaporation pressure is set to a higher value. Therefore, compared with the control of setting the target value of the evaporation temperature or evaporation pressure to be constant, the operation with reduced refrigeration capacity can be performed. On the other hand, when the temperature of the cooling object is lower, the target value of the evaporation temperature or evaporation pressure is set to a lower value, so that the refrigeration capacity can be appropriately exerted.

[0109] (3) The valve control unit may also have a control mode for controlling the expansion valve in such a way that the evaporation temperature or evaporation pressure reaches the target value changed by the target value changing unit in a state where the flow control valve is fully open.

[0110] In this technical solution, the valve control unit has a control mode for controlling the expansion valve in a state where the flow control valve is fully open. Therefore, it is possible to perform control other than the control of the flow control valve corresponding to the refrigeration requirement degree or the temperature of the object to be cooled. Therefore, as a refrigeration device, more flexible operation can be performed.

[0111] (4) The refrigeration device may further include: a pressure detector configured to detect the suction pressure of the compressor. In this case, the valve control unit may be configured to control the other one of the expansion valve and the flow control valve so that the detection value of the pressure detector reaches a suction pressure target value set according to the refrigeration requirement degree.

[0112] In this technical solution, one of the expansion valve and the flow control valve is controlled so that the evaporation temperature or evaporation pressure in the evaporator reaches a target value, and on the other hand, the other one of the expansion valve and the flow control valve is controlled so that the detection value of the pressure detector reaches a suction pressure target value set according to the refrigeration requirement degree. Therefore, not only is the evaporation temperature adjusted to the target value, but also the suction pressure is adjusted to the target value. That is, the refrigeration capacity is adjusted by adjusting the suction pressure, so that the refrigeration capacity can be changed with respect to the adjusted evaporation temperature. In addition, it is possible to prevent the suction pressure from being excessively reduced when the evaporation temperature is adjusted to the target value. Therefore, it contributes to the stable operation of the compressor.

[0113] (5) The refrigeration device may further include: a reception unit configured to receive information indicating the refrigeration requirement degree or the temperature of the object to be cooled.

[0114] (6) The environment forming device according to the embodiment includes: an environmental chamber; and the refrigeration device for cooling the inside of the environmental chamber.

[0115] (7) The refrigeration method according to the embodiment uses a refrigeration device including a refrigeration circuit in which a compressor, a condenser, an expansion valve, an evaporator, and a flow control valve are sequentially arranged and refrigerant is circulated. The refrigeration method performs the following steps: changing the target value of the evaporation temperature or evaporation pressure in the evaporator; controlling one of the expansion valve and the flow control valve based on the changed target value; receiving, by the reception unit of the refrigeration device, information indicating the refrigeration requirement degree or the temperature of the object to be cooled; and controlling the other one of the expansion valve and the flow control valve according to the refrigeration requirement degree or the temperature of the object to be cooled indicated by the information received by the reception unit.

[0116] As described above, according to the embodiment, frosting in the evaporator can be suppressed, and more flexible operation can be performed.

[0117] This application is based on Japanese Patent Application No. 2023-196739 filed on November 20, 2023, the content of which is incorporated herein by reference. That is, this application claims the priority of a Japanese patent application filed on November 20, 2023 (Application No. 2023-196739), and the entire content of this patent application is hereby incorporated by reference into this text.

Claims

1. A refrigeration device, characterized in that include: The refrigeration circuit is sequentially equipped with a compressor, a condenser, an expansion valve, an evaporator and a flow regulating valve, and circulates the refrigerant; a valve control unit configured to control the expansion valve and the flow regulating valve; and A target value changing unit is used to change the target value of the evaporation temperature or the evaporation pressure in the evaporator, wherein: The valve control unit controls one of the expansion valve and the flow rate regulating valve based on the target value changed by the target value changing unit, and controls the other of the expansion valve and the flow rate regulating valve according to a cooling requirement or a temperature of a cooling target.

2. The refrigeration device according to claim 1, characterized in that: The target value changing unit is configured to set the target value to a first target value when the temperature of the cooling object is a first temperature; and to set the target value to a second target value lower than the first target value when the temperature of the cooling object is a second temperature lower than the first temperature.

3. The refrigeration device according to claim 1, characterized in that: The valve control unit has a control mode for controlling the expansion valve so that the evaporation temperature or the evaporation pressure reaches the target value changed by the target value changing unit when the flow rate regulating valve is fully opened.

4. The refrigeration device according to claim 1, characterized in that Also includes: A pressure detector is configured to detect the suction pressure of the compressor, wherein: The valve control unit is configured to control the other of the expansion valve and the flow rate regulating valve so that the detection value of the pressure detector reaches a suction pressure target value set according to the cooling request degree.

5. The refrigeration device according to claim 1, characterized in that Also includes: The receiving unit is configured to receive information indicating the cooling request degree or the temperature of the cooling target.

6. An environment forming device, characterized in that include: Environmental chamber; as well as The refrigeration device according to any one of claims 1 to 5, used for cooling the environmental room.

7. A refrigeration method, characterized in that Using a refrigeration device, the refrigeration device comprising: The refrigeration circuit is equipped with a compressor, a condenser, an expansion valve, an evaporator and a flow control valve in sequence, and circulates the refrigerant. The refrigeration method is performed as follows: changing a target value of an evaporation temperature or an evaporation pressure in the evaporator; controlling one of the expansion valve and the flow control valve based on the changed target value; receiving, by a receiving unit of the refrigeration device, information indicating a degree of refrigeration demand or a temperature of a cooling object; The other of the expansion valve and the flow rate regulating valve is controlled based on the information received by the receiving unit, the indicated cooling requirement, or the temperature of the cooling target.

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