JP6210665B2 - Refrigeration apparatus and constant temperature and humidity apparatus equipped with the same - Google Patents

Description

The present invention relates to a refrigeration apparatus and a constant temperature constant humidity device having the same.

  As background art of this technical field, there is Japanese Patent No. 3974358 (Patent Document 1). In this patent document, “an electronic expansion valve has been conventionally used for such refrigeration capacity control. However, the electronic expansion valve has a limit in the processing accuracy of the needle for adjusting the refrigerant flow rate. Therefore, the refrigerating capacity could not be controlled usually at about 30% or less. "(See summary).

Japanese Patent No. 3974358

In the refrigeration apparatus that controls the electronic expansion valve using the evaporation temperature, when the electronic expansion valve is fully closed, the evaporation temperature corresponding to the pressure cannot be obtained. Conventionally, in order to avoid the possibility that the electronic expansion valve is fully closed, the usable lower limit opening degree of the electronic expansion valve needs to be set to be more open than the opening degree at which the electronic expansion valve is fully closed. . Since it cannot be used at a low opening near the fully closed position, there was a limit to keeping the refrigeration capacity low. Therefore, a heater output is required to cancel the surplus refrigeration capacity, which has been an obstacle to reducing the power consumption of the constant temperature and humidity chamber.
Therefore, the present invention uses an expansion mechanism at a low opening so that excessive refrigeration capacity is not generated in an area where refrigeration capacity is not required, and unnecessary heater output is reduced, thereby reducing power consumption of the entire apparatus. The purpose is to reduce.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-mentioned problems. For example, a compressor that compresses a refrigerant, a condenser that dissipates heat of the refrigerant compressed by the compressor, and the condenser In the refrigeration apparatus, comprising: an expansion valve that depressurizes the refrigerant radiated in the above; an evaporator that evaporates the refrigerant depressurized by the expansion valve; and a control unit that controls the opening degree of the expansion valve. When the outlet side refrigerant temperature of the expansion valve is higher than the target temperature, the opening degree of the expansion valve is reduced, and when the outlet side refrigerant temperature is lower than the target temperature, the opening degree of the expansion valve is increased. When the outlet side refrigerant temperature is higher than the target temperature and the opening degree of the expansion valve is reduced, the opening degree of the expansion valve is increased when the outlet side refrigerant temperature becomes high To reduce the outlet side refrigerant temperature. And, in the opening operation, opening of the expansion valve, when the refrigerant through the expansion valve reaches a predetermined opening is known to flow, the outlet refrigerant temperature even though increased The valve opening operation is stopped ”.

  According to the present invention, by using the expansion mechanism at a low opening degree, it is possible to prevent excessive refrigeration capacity from being generated in an area where the refrigeration capacity is not required, and to reduce unnecessary heater output. Can be reduced.

It is an example of the structure of the constant temperature and humidity apparatus for environmental tests. It is an example of the block diagram of a freezing apparatus. It is a flowchart which adjusts an electronic expansion valve. It is a flowchart which detects full closure.

  Hereinafter, embodiments will be described with reference to the drawings.

In this embodiment, an example of a constant temperature and humidity device for environmental testing will be described.
FIG. 1 is an example of a device configuration of a constant temperature and humidity device for an environmental test. A blower 11 is provided in the test chamber to circulate air. A humidifier 12, a refrigeration / dehumidifier 13, and a heater 14 are arranged in the suction portion of the blower 11, and each output is adjusted by the controller 15 so that the temperature sensor 16 and the humidity sensor 17 have the target temperature and humidity. . FIG. 1 shows an example of a constant temperature and humidity chamber in which humidity control is possible. However, in the case of a constant temperature bath that does not perform humidity control, the humidifier 12 and the humidity sensor 17 are omitted, and the freezing and dehumidifying device 13 is a freezing device. .

  In this embodiment, a platinum resistance thermometer is used for the temperature sensor 16 and the humidity sensor 17, and the temperature is directly measured and the humidity is calculated by the dry and wet bulb method. However, the humidity is directly measured using a polymer humidity sensor or the like. You may measure. Further, a thermocouple or a thermistor may be used instead of the platinum resistance thermometer.

  That is, the constant temperature and humidity apparatus of the present embodiment includes a refrigeration apparatus (refrigeration and dehumidification apparatus 13) that cools the test chamber that creates an environment of test conditions, a heating apparatus 14 that heats the test chamber, and a dehumidification of the test chamber. Dehumidifying device (refrigeration and dehumidification device 13), humidifying device 12 for humidifying the test chamber, freezing device (refrigeration and dehumidification device 13), heating device 14, dehumidifying device (refrigeration and dehumidification device 13), or humidification A control unit (controller 15) that controls the device 12, and the control unit (controller 15) is a refrigeration device (refrigeration and dehumidification device 13), a heating device 14, a dehumidification device (refrigeration and dehumidification device 13), or a humidification device. 12 is controlled to set the test chamber to the target temperature or the target humidity.

  FIG. 2 is an example of a configuration diagram of a refrigeration apparatus (refrigeration and dehumidification apparatus 13) in the constant temperature and humidity apparatus of the present embodiment. The refrigerant is compressed by the compressor 1 and radiated by the condenser 2 to be liquefied. By passing through the electronic expansion valve 3, the pressure decreases, and the evaporator 4 receives heat and vaporizes. The vaporized refrigerant is compressed again by the compressor 1. The expansion mechanism 3 includes a resistance variable mechanism for changing the refrigerant flow rate, and the controller 6 adjusts the opening degree of the electronic expansion valve 3 so that the temperature of the temperature sensor 5 approaches the target temperature. The temperature measured by the temperature sensor 5 is an evaporation temperature corresponding to the pressure of the evaporator 4.

  FIG. 3 is a flowchart when the controller 6 adjusts the opening degree of the electronic expansion valve 3. If the temperature of the temperature sensor 5 is higher than the target temperature and the current opening is equal to or higher than the lower limit opening, the opening of the electronic expansion valve 3 is reduced, and if the temperature of the temperature sensor 5 is lower than the target temperature, The opening degree of the electronic expansion valve 3 is increased.

  When the target temperature of the controller 6 is low and the opening degree of the electronic expansion valve 3 must be used near the lower limit, the resistance becomes excessive and the refrigerant may not flow. When the refrigerant stops flowing, the temperature of the temperature sensor 5 is no longer the evaporation temperature corresponding to the pressure of the evaporator 4, making it difficult to control the refrigerant flow rate. Although the minimum value of the opening degree of the electronic expansion valve 3 is provided in order to prevent the refrigerant from flowing, the individual value of the electronic expansion valve 3 needs to be taken into consideration, and therefore the minimum value of the opening degree has a margin. Therefore, it was difficult to use in a low opening range.

  FIG. 4 is a control flowchart of the electronic expansion valve to which a full-close detection means is added. If the temperature of the temperature sensor 5 is higher than the target temperature, the opening degree of the electronic expansion valve 3 is reduced. However, if the measured temperature of the temperature sensor 5 rises after the opening degree is reduced, it is determined that the refrigerant has stopped flowing. The opening degree of the electronic expansion valve 3 is increased. After increasing the opening degree of the electronic expansion valve 3, the temperature of the temperature sensor 5 before and after the opening degree change is compared again, and if the increase continues, the opening degree is further increased. This is repeated until the temperature begins to drop. However, if the opening reaches a position where it is known that the refrigerant flow can be reliably obtained even when the individual difference of the electronic expansion valve 3 is taken into consideration, no further valve opening operation is performed.

  As described above, the basic control of the control unit (controller 6) is to reduce the opening of the electronic expansion valve 3 when the outlet side refrigerant temperature of the electronic expansion valve 3 is higher than the target temperature, and to set the outlet side refrigerant temperature. When the temperature is lower than the target temperature, the opening degree of the electronic expansion valve 3 is increased. When the outlet side refrigerant temperature is higher than the target temperature and the opening degree of the electronic expansion valve 3 is reduced, when the outlet side refrigerant temperature becomes high, the refrigerant flows because the electronic expansion valve 3 is closed. The outlet refrigerant temperature is lowered by determining that it has disappeared and increasing the opening of the electronic expansion valve 3.

  When the measured temperature of the temperature sensor 5 rises, the opening degree may not be changed step by step, but may be increased to an opening degree that the refrigerant is known to flow reliably. Further, the opening degree of the expansion valve at which the temperature measured by the temperature sensor 5 is increased may be recorded, and an opening degree slightly larger than this may be handled as the lower limit opening degree. By handling an opening that is slightly larger than the opening of the expansion valve at which the temperature measured by the temperature sensor 5 has been raised as the lower limit opening, it is possible to prevent the repeated opening of the refrigerant from being instructed.

  That is, the control unit (controller 6) opens the electronic expansion valve 3 when the outlet side refrigerant temperature becomes high when the opening degree of the electronic expansion valve 3 is reduced when the outlet side refrigerant temperature is higher than the target temperature. The degree of opening is stored, and an opening larger than the stored opening is set as the lower limit opening of the electronic expansion valve 3.

  According to this embodiment, it is not necessary to uniformly provide the minimum opening, and the electronic expansion valve can be used up to the opening just before being fully closed. The same effect can be obtained even in a thermostatic chamber without a humidity control function.

  According to the present inventor's confirmation, according to the present embodiment, the expansion mechanism can be used at a low opening degree as described above, but this makes it possible to compare the minimum refrigerant flow rate of the electronic expansion valve with the conventional one. About 30%. Since it is possible to prevent excessive refrigeration capacity from being generated in a region where the refrigeration capacity is not required, unnecessary heater output is reduced, and the entire apparatus has an effect of reducing power consumption by up to 30%.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Electronic expansion valve 4 Evaporator 5 Temperature sensor 6 Controller 11 Blower 12 Humidifier 13 Refrigeration / dehumidifier 14 Heating device

Claims (3)

A compressor for compressing the refrigerant;
A condenser for radiating heat of the refrigerant compressed by the compressor;
An expansion valve that depressurizes the refrigerant radiated by the condenser;
An evaporator for evaporating the refrigerant decompressed by the expansion valve;
In a refrigeration apparatus comprising a control unit that controls the opening of the expansion valve,
The controller is
When the outlet side refrigerant temperature of the expansion valve is higher than the target temperature, the opening degree of the expansion valve is reduced, and when the outlet side refrigerant temperature is lower than the target temperature, the opening degree of the expansion valve is increased.
When the outlet side refrigerant temperature is higher than the target temperature and the opening degree of the expansion valve is reduced, the opening operation of increasing the opening degree of the expansion valve when the outlet side refrigerant temperature becomes high To lower the outlet side refrigerant temperature,
In the valve opening operation, when the opening degree of the expansion valve reaches a predetermined opening degree at which the refrigerant is known to flow through the expansion valve, even if the outlet-side refrigerant temperature has risen, A refrigeration apparatus characterized by stopping the valve opening operation. The refrigeration apparatus according to claim 1,
The controller is
When the outlet side refrigerant temperature is higher than the target temperature and the opening degree of the expansion valve is reduced, the opening degree of the expansion valve when the outlet side refrigerant temperature becomes high is stored,
A refrigerating apparatus characterized in that an opening larger than the stored opening is set as a lower limit opening of the expansion valve. A refrigeration system that cools the test chamber to create an environment of test conditions;
A heating device for heating the test chamber;
A dehumidifying device for dehumidifying the test chamber;
A humidifier for humidifying the test chamber;
A controller that controls the refrigeration apparatus, the heating apparatus, the dehumidifying apparatus, or the humidifying apparatus,
In the constant temperature and humidity device, the control unit controls the refrigeration device, the heating device, the dehumidifying device, or the humidifying device to set the test chamber to a target temperature or a target humidity.
A constant temperature and humidity apparatus, wherein the refrigeration apparatus is the refrigeration apparatus according to claim 1 or 2.