JPH05157427A - Refrigerating device - Google Patents

Abstract

PURPOSE:To obtain a high humidity freezing device capable of lowering the temperature in a thermal insulation box promptly without lowering the humidity in the thermal insulation box. CONSTITUTION:A suction side and a discharge side of a refrigerant compressor 11 are communicated with a bypass 18 having a solenoid valve 16 and a capillary 17. When a detected temperature of a thermistor 29 is higher than a reference temperature, the solenoid valve 16 is closed while it is lower than the reference value, the solenoid valve 16 is opened. When the solenoid valve 16 is closed, all refrigerant is supplied to a vaporizer 14, which results in an increase in a freezing capacity. Therefore, this construction makes it possible to cool the thermal insulation box 2 promptly. When the solenoid valve 16 is opened, a part of the refrigerant returns to the refrigerant compressor 11 so that the vaporization temperature of the vaporizer is increased while its freezing capacity is reduced, thereby enabling high humidity operation to be carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating device which prevents a decrease in humidity in a cool box and maintains a high relative humidity.

[0002]

2. Description of the Related Art A refrigerator, such as a refrigerator, which keeps the temperature inside a cool box (hereinafter referred to as "inside box") below a target temperature, detects the temperature inside the box and responds to the detected temperature. By controlling the operation and stop of the refrigerant compressor, the refrigerating capacity of the evaporator in the refrigerating cycle is adjusted.
In this case, in general, there is a difference between the temperature of the evaporator that cools the inside of the refrigerator and the temperature of the inside of the refrigerator, and the air inside the refrigerator is once cooled to the temperature of the evaporator and then mixed with other air. Is maintained below the target temperature. Further, in the refrigeration system, when the air inside the refrigerator is cooled, the absolute humidity Φ decreases, so that the relative humidity φ inside the refrigerator easily decreases accordingly. Here, the relative humidity φ in the refrigerator does not always correspond to only the temperature in the refrigerator, and as shown in FIG.
Even if it is 1, when the temperature of the evaporator is Te1, the relative humidity Φ1 with respect to the temperature Te1 easily falls to the relative humidity Φ1 indicated by the point M which is the amount of water vapor at the internal temperature T1. When Te2 is lower than Te1, the relative humidity φ2 with respect to the temperature Te2 tends to decrease to the relative humidity φ2 (where φ1> φ2) indicated by the point N at which the amount of water vapor at the internal temperature T1 is obtained, and the temperature Te of the evaporator is generally decreased. The lower the relative humidity, the lower the relative humidity φ. In FIG. 6, a solid line A indicates a saturation line of absolute humidity Φ with respect to temperature, and broken lines B and C indicate relative humidity φ.
The values of absolute humidity Φ with respect to each temperature when 1 and φ2 are shown.

For this reason, in order to prevent the food and other cooling products in the refrigerator from being dried, a large-sized evaporator is used to reduce the ratio of the amount of refrigerant to be evaporated with respect to the size of the evaporator. Where the evaporation temperature of the refrigerant in the container is set high, or the evaporator is embedded in the inside wall of the container and the wall between the inside wall and the evaporator has a double structure, and the temperature of the cooling surface of the inside air and the inside of the container There is a high-humidity refrigeration system that makes it difficult to reduce the humidity inside the refrigerator due to the structure that makes it difficult to lower the cooling temperature when the air inside the refrigerator is cooled by the evaporator, such as the one with a smaller temperature difference from the temperature. is there.

[0004]

However, the above-mentioned high-humidity refrigerating apparatus is expensive when the evaporator is large or the structure of the cool box is very complicated, and when the evaporator is not large. Is designed to maintain high humidity by lowering the cooling capacity and raising the cooling temperature of the air inside the refrigerator, so especially in the mobile refrigeration system (cold roll box), etc. When the inside temperature is high, such as immediately after the door is opened, or when the inside temperature rises, it takes time for the inside temperature to drop to the target temperature if the evaporator is small, There is a problem that the internal temperature cannot be lowered promptly.

An object of the present invention is to provide a refrigerating apparatus which can cool quickly when the temperature inside the refrigerator is high, and can maintain high humidity at that time without lowering the humidity inside the refrigerator. To do.

[0006]

The present invention provides a refrigerant compressor,
A condenser, a fixed throttle member, and an evaporator are connected in sequence to form a refrigeration cycle, the evaporator is placed in a cool box, and the temperature is detected on the basis of the temperature detected by a temperature detecting means for detecting the temperature in the cool box. In a refrigeration system that controls a refrigerant compressor to maintain the temperature in the cold storage below a target temperature, a side passage that has an on-off valve and a throttle member and connects the suction side and the discharge side of the refrigerant compressor is provided. When the temperature detected by the temperature detecting means is higher than a reference temperature that is set high in a predetermined relationship with the target temperature, the on-off valve is closed, and when the temperature is lower than the reference temperature, the on-off valve is opened. That is the technical means.

[0007]

In the present invention, when the on-off valve is closed in the refrigeration cycle, all the refrigerant discharged from the refrigerant compressor circulates through the condenser, the fixed throttle member and the evaporator, and a large amount of refrigerant is stored in the evaporator. Since the refrigerant is supplied and the amount of the refrigerant evaporated in the evaporator increases, a large refrigerating capacity is obtained and the temperature of the evaporator becomes low. On the contrary, when the on-off valve is open, a part of the refrigerant discharged from the refrigerant compressor is directly returned to the refrigerant compressor without being circulated in the evaporator and the amount of the refrigerant supplied to the evaporator is small. Since the amount decreases, the refrigerating capacity decreases and the temperature of the evaporator rises.

Therefore, when the detected temperature in the cool box is higher than the reference temperature which is set higher than the target temperature in a predetermined relationship, the on-off valve is closed and the refrigerating capacity of the evaporator is increased. The temperature in the cool box can be quickly lowered. At this time, the temperature of the evaporator becomes low, and the temperature decrease range of the internal air becomes large, but the temperature of the internal air is higher than the reference temperature that is set higher than the target temperature. Even if the temperature decrease range by the evaporator is large, it is not too low with respect to the target temperature. When the detected temperature in the cool box is lower than the reference temperature, the on-off valve opens and the refrigerating capacity becomes smaller.Therefore, the temperature of the evaporator becomes higher and the temperature in the cool box becomes lower than the target temperature without lowering the humidity. Can be maintained. Therefore, regardless of the temperature in the cool box, the air in the cool box is not excessively cooled to the target temperature, and the water vapor contained in the air in the cool box is less likely to condense. It can be maintained at high humidity.

[0009]

According to the present invention, the refrigerating capacity is increased when the temperature inside the cool box is high. Therefore, the cool box temperature should be lowered promptly at the beginning of operation or after the door of the cool box is opened. You can Further, when the temperature in the cool box is low, the refrigerating capacity is lowered, so that the temperature in the cool box can be maintained below the target temperature while performing high humidity operation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on an embodiment of a refrigerating apparatus 1 used as an on-vehicle cold roll box. In the refrigeration system 1 shown in FIG. 1, as a refrigeration cycle 10, a refrigerant compressor 11, a condenser (condenser) 12, a capillary 13, an evaporator (evaporator) 14, and an accumulator 15 form a circulation path by a conduit member. A cool box 2 that is connected and has the evaporator 14 formed of a heat insulating material or the like.
It is arranged inside to cool the inside of the cool box 2.
Further, in order to maintain the humidity in the cool box 2 at a high level without lowering the humidity, a bypass 18 in which an upstream side of the condenser 12 and a downstream side of the evaporator 14 are connected in series with a solenoid valve 16 and a capillary 17 is provided. The amount of refrigerant passing through the evaporator 14 can be adjusted by connecting the above. here,
When the solenoid valve 16 is opened, as indicated by a dashed arrow,
Part of the refrigerant circulating in the refrigeration cycle 10 is the bypass 1
8 and returns to the refrigerant compressor 11, the amount of refrigerant passing through the evaporator 14 decreases. As a result, when the solenoid valve 16 is in the open state, the cooling capacity of the evaporator 14 decreases,
Since the temperature of the air inside the refrigerator to be cooled by the evaporator 14 is reduced and the target temperature is not excessively cooled, it is possible to maintain high humidity without lowering the humidity inside the refrigerator. Further, when the solenoid valve 16 is closed, all the refrigerant circulated by the refrigerant compressor 11 passes through the evaporator 14 as indicated by the solid arrow, so that the cooling capacity of the evaporator 14 becomes large. Therefore, it is possible to quickly reduce the temperature inside the refrigerator. The evaporator 14 in the cool box 2 is provided with a cooling fan 3 for performing forced convection in the cool box 2, and the condenser 12 is provided with a heat radiating fan 4.

The refrigerating cycle 10 having the above structure is
The controller 20 controls the temperature inside the cool box 2 and the refrigerating capacity of the evaporator 14. The control device 20 is shown in FIG.
As shown in, it is operated by electric power supplied from an AC power source L such as a commercial power source or an in-vehicle generator, and is converted into direct current by a power transformer 21, a rectifier 22 with four diodes connected in a bridge, and a capacitor 23. A control unit 24 operated by a barrel control power supply;
The driving unit 30 is directly driven by the AC power supply L. The control unit 24 includes a control circuit 25, a compressor relay 26 controlled by the control circuit 25, an electromagnetic valve relay 27, a cooling fan relay 28, and a contact 28 of the cooling fan relay 28.
A fan motor 3a of the cooling fan 3 connected to a is provided. Further, the control circuit 25 includes a thermistor 29 for detecting the temperature inside the cool box 2 in order to control each relay.

The drive unit 30 includes an AC electric motor 31 for driving the refrigerant compressor 11 in the refrigeration cycle 10,
An induction circuit 32 for operating the AC electric motor 31, which includes a starting capacitor, a starting relay, and a driving capacitor;
An electromagnetic contactor 33 for opening and closing a contact 33a provided in the induction circuit 32 for controlling the induction circuit 32; a drive motor 4a for the heat dissipation fan 4 connected in parallel to the electromagnetic contactor 33;
The coil 16a of the solenoid valve 16 is provided. The electromagnetic contactor 33 and the drive motor 4a are connected to the AC power source L via the contact 26a of the compressor relay 26, and the coil 16a of the solenoid valve 16 is connected to the contact 27 of the solenoid valve relay 27.
It is connected to the AC power supply L via a. A circuit breaker is provided in the control device 20 between it and the AC power supply L.

Next, the refrigeration cycle 1 by the control circuit 25
The control of 0 will be described. The control circuit 25 is used for the cool box 3
Based on the temperature T detected by the thermistor 29 therein, temperature control in which the operation of the refrigerant compressor 11 is controlled and the temperature inside the cool box 2 is maintained below the target temperature Ta, and the temperature inside the cool box 2 is controlled. When the temperature rises, the temperature is quickly lowered and the refrigerating capacity is controlled to maintain the inside of the cool box 2 at high humidity. In the temperature control, the detected temperature T is the target temperature Ta.
When the detected temperature T is lower than the target temperature Ta, the refrigerant compressor 11 is stopped, and the refrigerant compressor 11 is stopped. Further, in conjunction with the operation stop of the refrigerant compressor 11, the operation stop of the cooling fan 3 and the heat radiation fan 4 is controlled. In the refrigerating capacity control, the evaporator 14 is cooled according to the detected temperature T in order to keep the temperature in the cool box 2 at the target temperature Ta or less as quickly as possible while preventing the humidity in the cool box 2 from decreasing. Control the ability. Here, the detected temperature T in the cool box 2 when the refrigerant compressor 11 is driven is a predetermined temperature ΔT with respect to the target temperature Ta of the cool box 2.
Reference temperature Ts (= Ta + ΔTα that is higher by α; however, ΔTα
> 0), when the detected temperature T exceeds the reference temperature Ts, the electromagnetic valve 16 is closed and all the refrigerant circulated by the refrigerant compressor 11 is condensed by the condenser 12 and the evaporator 14.
To increase the refrigerating capacity of the evaporator 14 and the detected temperature T is equal to or lower than the reference temperature Ts,
The electromagnetic valve 16 is opened to directly return a part of the refrigerant circulated by the refrigerant compressor 11 to the refrigerant compressor 11 via the accumulator 15 without passing through the evaporator 14 or the like, and the freezing by the evaporator 14 is performed. Reduce capacity.

Next, the operation of the refrigerating apparatus 1 of the present embodiment having the above construction will be described with reference to FIG. Control circuit 2
When a power switch (not shown) is turned on, 5 turns on the compressor relay 26 to drive the refrigerant compressor 11 and closes the contact 26a. As a result, the drive motor 4a operates to operate the heat dissipation fan 4, the contact 33a of the electromagnetic contactor 33 closes, the induction circuit 32 starts the AC electric motor 31, and the refrigerant compressor 11 operates (step S1). .. At this time, the cooling fan relay 28 is also energized and the contact 28a is closed.
When a is energized, the cooling fan 3 also operates. AC motor 3
When 1 starts rotating, in the refrigeration cycle 10, the refrigerant compressor 11 compresses and discharges the refrigerant, so that the refrigerant in the refrigeration cycle 10 sequentially passes through the condenser 12, the capillary 13, the evaporator 14, and the accumulator 15. pass. Also,
Based on the temperature T detected by the thermistor 29, the solenoid valve relay 2
7 is controlled, and when the detected temperature T is higher than the reference temperature Ts (NO in step S2), the contact 27a is opened and the coil 16a is not energized, so the solenoid valve 16 is controlled to be in the closed state (step S3), Since all the refrigerant supplied from the refrigerant compressor 11 passes through the evaporator 14,
Freezing capacity increases. Conversely, the detected temperature T is the reference temperature T
When it is lower than s (YES in step S2),
Since the contact 27a is closed and the coil 16a is energized, the solenoid valve 16 is controlled to be in the open state (step S4), and a part of the refrigerant supplied from the refrigerant compressor 11 does not pass through the evaporator 14 and is compressed by the refrigerant. Since it returns to the machine 11, the refrigerating capacity is reduced. In the meantime, in the condenser 12, the high-temperature and high-pressure gas-phase refrigerant is cooled by the airflow of the heat radiating fan 4 and changed into the liquid refrigerant, and the liquid refrigerant that has passed through the capillary 13 into the evaporator 14 little by little is evaporated. The heat in the cool box 2 is taken by the container 14 to evaporate and cool the evaporator 14, and again becomes a gas-phase refrigerant and is sucked into the refrigerant compressor 11.

Therefore, as shown in FIG. 4, when the electromagnetic valve 16 is closed and the refrigerating capacity is high, the temperature of the evaporator 14 corresponds to a large amount of refrigerant circulation passing through the evaporator 14. As indicated by X, the temperature is significantly lower than the temperature inside the cool box 2, and conversely, when the electromagnetic valve 16 is open and the refrigerating capacity is small, a small amount of refrigerant circulating through the evaporator 14 is generated. Correspondingly, as indicated by the point Y, the value does not become so low with respect to the temperature inside the cool box 2. After that,
The detected temperature T is compared with the target temperature Ta, and when the detected temperature T is higher than the target temperature Ta (NO in step S5), the process proceeds to step S1 and the above steps are repeated to further decrease the detected temperature T. When the detected temperature T becomes equal to or lower than the target temperature Ta (YES in step S5), the energization of the compressor relay 26 is stopped and the contact 2
6a is opened, the contact 33a of the electromagnetic contactor 33 is opened, the driving of the AC motor 31 is stopped, the refrigerant compressor 11 is stopped (step S6), and at the same time, the driving of the heat radiation fan 4 is stopped. At this time, the solenoid valve relay 27 is de-energized, the solenoid valve 16 is closed, and the driving of the cooling fan 3 is stopped. Then, the process proceeds to step S5, and the refrigerant compressor 1 is operated until the detected temperature T becomes higher than the target temperature Ta.
1 to stop the operation of the refrigeration cycle 10.

By performing the above control operation, in the refrigerating apparatus 1 of this embodiment, the electromagnetic valve 16 is closed with a large refrigerating capacity from the start of operation until the detected temperature T drops to the reference temperature Ts. When it is operated and becomes lower than the reference temperature Ts, the solenoid valve 16 is opened, the refrigerating capacity is reduced, and high humidity operation is performed. As a result, as shown in FIG. 5, the temperature in the cool box 2 can be lowered in a relatively short time, and the humidity in the cool box 2 is lowered because the high-humidity operation is performed at the reference temperature Ts or lower. There is nothing to do.

In the above embodiment, the target temperature Ta
Both the reference temperature Ts and the reference temperature Ts are set by giving a predetermined temperature range, and the operation start temperature and the stop temperature of the refrigerant compressor 11 and the opening temperature and the closing temperature of the solenoid valve 16 are different temperatures. Is set.

As described above, according to this embodiment, the temperature in the cool box can be cooled to the target temperature in a relatively short time after the power is supplied, and the humidity in the cool box can be kept high. Can be maintained at. Therefore, in applications where it is not necessary to operate the refrigeration cycle at all times, for example, in cases where food or the like is transported from the production site to the market, where cooling is required for only one way, etc. Efficiency is good because the operating time can be shortened. Although the solenoid valve is used as the on-off valve in the above embodiment, a two-way valve may be used. In the above embodiment, the refrigerant compressor is driven by the AC electric motor using the AC power source, but it may be driven by the engine.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a refrigerating apparatus according to an embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing a control device of the refrigerating apparatus according to the embodiment of the present invention.

FIG. 3 is a flowchart showing a control operation of the refrigerating apparatus according to the embodiment of the present invention.

FIG. 4 is a characteristic diagram for explaining the temperature decrease with respect to the amount of refrigerant in the evaporator of the refrigeration system of the embodiment of the present invention.

FIG. 5 is a time chart showing changes in the internal cold storage temperature for explaining the effect of the refrigerating apparatus of the present invention.

FIG. 6 is a characteristic diagram showing the absolute humidity with respect to the temperature for explaining the relationship between the internal temperature and the evaporator temperature and the absolute humidity and the relative humidity in the refrigerating apparatus.

[Explanation of symbols]

 1 Refrigerator 2 Refrigerator 10 Refrigeration Cycle 11 Refrigerant Compressor 12 Condenser 13 Capillary (fixed throttle member) 14 Evaporator 16 Electromagnetic valve (open / close valve) 17 Capillary (throttle member) 18 Bypass (bypass) 29 Thermistor (temperature detection) means)

Claims (1)

[Claims] 1. A temperature at which a refrigerant compressor, a condenser, a fixed throttle member, and an evaporator are sequentially connected to form a refrigeration cycle, the evaporator is arranged in a cold storage, and the temperature in the cold storage is detected. In a refrigeration system for controlling the refrigerant compressor based on the temperature detected by a detection means to maintain the temperature inside the cold storage below a target temperature, an on-off valve and a throttle member are provided and a suction side and a discharge side of the refrigerant compressor. A side passage communicating with the side is provided, and when the temperature detected by the temperature detecting means is higher than a reference temperature set high in a predetermined relationship with respect to the target temperature, the on-off valve is closed and the temperature is higher than the reference temperature. A refrigerating apparatus which opens the on-off valve when the temperature is low.