JPH10160303A - Defrosting controller of refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the defrosting control system of a refrigerating machine, and to effectively perform defrosting in the off-cycle defrosting mode. SOLUTION: Cooling of a refrigeration chamber is started (S200), and it is judged whether or not the temperature in the refrigeration chamber is <=0 deg.C (S300). When the result of judgment is YES (S300), cooling of the refrigeration chamber is started, and it is judged whether or not the prescribed time is elapsed (S400). When the result of judgment is YES, the hot gas, defrosting is performed (S500). After the temperature in the refrigeration chamber is <=0 deg.C, and when the temperature of the refrigeration chamber is >=10 deg.C between the hot gas defrosting operations, the off-cycle defrosting is performed (S900).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting control for a refrigerator, and more particularly to a hot gas defrosting system in which a high-temperature refrigerant (hot gas) is sent to an evaporator of a refrigeration cycle to perform defrosting. The present invention relates to a method in which off-cycle defrosting is performed in combination with off-cycle defrosting in which the operation of a cycle is stopped and a fan is operated to perform defrosting.

[0002]

2. Description of the Related Art Conventionally, in defrosting control of a refrigerator, hot gas defrosting in which a high-temperature refrigerant (hot gas) is sent to an evaporator of a refrigeration cycle to perform defrosting is performed by using a high-temperature refrigerant. Therefore, since the temperature of the freezing room is raised by the heat at the time of the defrosting, there is a demand to reduce the number of times of the hot gas defrosting as much as possible. In order to realize this, it has been considered to use both the hot gas defrosting and the off-cycle defrosting in which the operation of the refrigeration cycle is stopped and the evaporator fan is operated to perform defrosting. ,
The following are known.

In this refrigerator, a door switch for detecting the opening and closing of a luggage carry-out door provided in a freezer compartment is provided. When it is determined that the door is opened by the door switch, off-cycle defrosting is performed in the freezer compartment. Defrosting is performed by the heat of the invading outside air, and the off-cycle defrosting is terminated when the door is closed.

[0004]

However, in the above-mentioned prior art, there is a problem that a system for connecting a door switch and a control device for controlling a freezing room becomes complicated. Further, for example, if the above-described off-cycle defrost is performed when the door opening time is short or at a low outside temperature,
When the door is closed after the frost adhering to the evaporator is slightly melted and the cooling of the freezing chamber is started again, there is a problem that frost adheres to the evaporator unnecessarily.

[0005] Therefore, the present invention provides a refrigerator defrost control device that simplifies the system of a refrigerator defrost control device and that can effectively perform defrost in off-cycle defrost. The purpose is to:

[0006]

The present inventor has studied the above-described off-cycle defrosting according to the opening and closing of the door, and has found the following. Hereinafter, this will be described.
In the off-cycle defrost, as described above, the off-cycle defrost starts when the door is opened, but in this off-cycle defrost, there is a remarkable change in the defrost capacity due to the outside temperature entering the room. I understood.

That is, when the outside air temperature is low and the door is opened and outside air enters the freezer compartment, the temperature in the freezer compartment does not change so much and frost adheres to the evaporator as described above. Found that there was no need to perform off-cycle defrost. On the other hand, when the outside air temperature was relatively high, it was found that the frost attached to the evaporator could be effectively defrosted by increasing the temperature inside the freezer compartment due to the outside air entering the freezer compartment.

Accordingly, the present inventor has noticed that when the outside air temperature is relatively high, the indoor temperature of the refrigerator rises from a low temperature when the door is opened. By performing the off-cycle defrost when the room temperature is low and the room temperature is low and then rising to a predetermined temperature, it was thought that the defrost could be effectively performed by the off-cycle defrost. .

According to the above-described concept, the invention according to the first to fifth aspects has an indoor temperature detecting means (21) for detecting the indoor temperature of the freezing room (2), and the defrost control means (6). After the indoor temperature detected by the indoor temperature detecting means (21) reaches the first predetermined temperature, the indoor temperature detected by the indoor temperature detecting means (21) is higher than a second predetermined temperature higher than the first predetermined temperature. Then, off-cycle defrosting is performed for a predetermined time.

[0010] Thus, after the room temperature of the freezing room is cooled to the first predetermined temperature, when the temperature rises to the second predetermined temperature higher than the first predetermined temperature, off-cycle defrosting is performed, so that the door switch is turned on. Not provided, the system for defrost control can be simplified, and defrost can be effectively performed by off-cycle defrost. The second predetermined temperature means a temperature at which frost is not excessively attached to the refrigeration evaporator even when the off-cycle defrost is performed, and the frost of the refrigeration evaporator can be effectively defrosted. is there.

According to the third aspect of the present invention, in the hot gas defrosting, the time during which the signal for cooling the freezer compartment (2) is generated by the cooling signal generating means (24) is equal to or longer than a predetermined time. Then, it is characterized in that it is configured to be performed. Thereby, the defrost of the evaporator can be effectively performed by the hot gas defrost in which the refrigerant compressed to a high temperature and a high pressure by the compressor flows into the evaporator.

Further, in the invention according to the fifth aspect, in the vicinity of the evaporator (11), an evaporator temperature detecting means (20) for detecting a physical quantity corresponding to a refrigerant temperature downstream of the evaporator.
Is provided, and when the temperature of the evaporator (11) detected by the evaporator temperature detecting means (20) becomes higher than a predetermined temperature, the hot gas defrosting is terminated.

Accordingly, when the physical quantity corresponding to the temperature on the downstream side of the evaporator detected by the evaporator temperature detecting means becomes higher than the predetermined temperature, and the frost adhering to the evaporator is sufficiently removed, the hot gas is removed. Defrosting can be terminated. In the present invention, since off-cycle defrosting is performed effectively, hot gas defrosting is performed, and the time during which the temperature of the evaporator becomes higher than the predetermined temperature is reduced. As a result, it is possible to suppress a rise in the temperature in the freezer compartment due to hot gas defrosting.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. In this embodiment, the refrigerator is applied to a refrigerator car. FIG. 1 shows an overall configuration diagram of a refrigerator car 1 of the present embodiment. As shown in FIG. 1, a freezing room (freezer) 2 is provided in a rear portion of the cabin of the freezer truck 1, and a frozen product such as frozen food is loaded in the freezing room 2. The freezer compartment 2 is provided with two carrying-out doors 4 and 5 for loading the frozen product into the freezer compartment 2 or carrying out the frozen product in the freezer compartment. As shown in the figure, the refrigerating car 1 has a well-known refrigerating cycle device 3 mounted on a front part of the vehicle.

FIG. 2 is a detailed view of the refrigeration cycle apparatus 3,
And a configuration diagram of a control device 6 for controlling the refrigeration cycle device 3. The refrigeration cycle apparatus 2 includes a compressor 7 for compressing and discharging the refrigerant to a high temperature and a high pressure, a condenser 8 for condensing the refrigerant compressed to a high temperature and a high pressure by the compressor 7, and a condenser 8 for condensing the refrigerant. A receiver 9 that separates the refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant and stores the liquid-phase refrigerant, a decompression device (a temperature-operated expansion valve in this embodiment) 10 that depressurizes the liquid-phase refrigerant, A refrigerating evaporator 11 for evaporating the separated refrigerant; an accumulator 12 installed between the refrigerating evaporator 11 and the compressor 7 for storing a liquid-phase refrigerant among the refrigerants passing through the refrigerating evaporator 11; And a refrigerant pipe 13 connecting them.

The compressor 7 is driven by a vehicle driving engine (not shown). The compressor 7 is switched so as to be selectively driven or stopped by a well-known electromagnetic clutch 14 which is a power interrupting device. The electromagnetic clutch 14 transmits the driving force of the running engine to the compressor 7 when energized, and shuts off the driving force from the running engine when energized.

The refrigeration cycle apparatus 3 according to the present embodiment is provided with a hot gas bypass passage 15 that communicates the discharge side of the compressor 7 with the downstream side of the pressure reducing device 10 and the upstream side of the refrigeration evaporator 11. Have been. The hot bypass channel 15 is provided with an electromagnetic valve 16 serving as an opening / closing unit. The condenser 8 is installed at a position that easily receives the traveling wind of the vehicle, and the traveling refrigerant and the cooling air blown by the blower fan 17 condense the internal refrigerant.

The refrigerating evaporator 11 is for cooling the refrigerating room 2 by latent heat of evaporation of the refrigerant. Further, a cooling fan 19 that blows air toward the freezing evaporator 11 is provided in the freezing room 2, and the cooling fan 19 cools the entire inside of the freezing room 2 with the freezing evaporator 11. The cooling air is blown to make the inside of the freezing room 2 have a uniform temperature distribution. The cooling fan 19 sucks air in the freezing room 2, passes the air through the freezing evaporator 11, and then sends cooling air into the freezing room 2 again.

A defrosting release sensor 20 for detecting a temperature near the refrigeration evaporator 11 is attached to the refrigerant pipe 13 near the refrigeration evaporator 11. Further, in the present embodiment, the defrost release sensor 20 is attached to the outer surface of the refrigerant pipe 13 immediately downstream of the refrigerating evaporator 11. The hot gas defrost described later is performed by the defrost release sensor 20.
Is terminated when the temperature detected by is higher than 3 ° C.

In the freezer compartment 2, a freezer compartment temperature sensor 21 for detecting the freezer compartment temperature is provided. The control device 6 has a timer function and the like and includes computer means such as a microcomputer. The control device 6 performs arithmetic processing based on an input signal from an input terminal and controls the refrigeration cycle device 3. Things.

The control device 6 includes, as input terminals, the defrost release sensor 20 described above, a freezer compartment temperature sensor 21, a temperature setter 22 for setting a set temperature in the freezer compartment, and a freezer compartment 2
And a cooling start switch 24 for starting the cooling of the cooling device. The temperature setter 22 is formed of, for example, a variable resistor or the like, and the set temperature can be arbitrarily changed in a range of, for example, ─10 ° C. to ─20 ° C.

On the other hand, the control device 6 is connected to an energizing circuit (not shown) of the electromagnetic clutch 14, an electromagnetic valve 16, a blower fan 17, and a cooling fan 19 as output terminals. The control device 6 is configured to be supplied with electric power by turning on an ignition switch (not shown) of the vehicle. Then, when the ignition switch is turned on, the cooling start switch 24 is turned on (generates a signal for cooling the freezing chamber 2).
Then, the temperature in the freezer compartment 2 is controlled by the control device 6 to the set temperature set by the temperature setter 22 (for example, # 2
0 ° C.).

More specifically, when the cooling start switch 24 is turned on, the control device 6 energizes the electromagnetic clutch 14 to connect the vehicle running engine and the compressor 7 to each other. Is driven (ON). Further, at this time, the control device 6 starts the cooling of the freezing compartment 2 by operating (ON) the blowing fan 17 and the cooling fan 19.

Thereafter, when the temperature of the freezer compartment detected by the freezer compartment temperature sensor 21 reaches the set temperature (─20 ° C.),
The power supply to the electromagnetic clutch 14 is cut off, the connection between the vehicle running engine and the compressor 7 is cut off (OFF), and the blower fan 17 and the cooling fan 19 are stopped (OFF). Then, for example, when the temperature in the freezing room 2 is slightly higher than the set temperature and reaches ─18 ° C., the compressor 7 is driven as described above, and the blowing fan 17 and the cooling fan 19 are operated. Note that the solenoid valve 16 is in a closed state (OFF) except when hot gas defrosting described below is performed.

As described above, in the refrigerating vehicle 1, since the freezing room temperature is extremely low, such as ─20 ° C., the frost adheres to the refrigerating evaporator 11, thereby cooling the refrigerating evaporator 11. Ability will be reduced. Therefore, in the refrigerating vehicle 1, defrost control for removing frost attached to the refrigerating evaporator 11 is performed. And in this embodiment,
As the defrost control, the control device 6 can operate a hot gas defrost control described later and an off-cycle defrost control described later.

FIG. 3 is a flowchart showing the contents of control of the freezing compartment 2, and will be described below with reference to this flowchart. FIG. 4 shows a time chart in this flowchart. When the refrigeration start switch 24 is turned on in a state where the ignition switch is turned on, this flowchart is executed, and at the start, data and a timer are initialized.

Then, in step S100, as the information reading, the set temperature set by the temperature setting unit 22 (here, ─20 ° C.) is read, and the detection value of the freezing room temperature sensor 21 and the defrosting release are performed. The detection value of the sensor 20 is read. Next, in step S200, a timer for hot gas defrosting described later is reset. At the same time, the compressor 7 is driven by energizing the electromagnetic clutch 14, and the blowing fan 17 and the cooling fan 1.
9 is started to start cooling the inside of the freezer compartment 2. When the temperature in the freezing compartment 2 is substantially equal to the set temperature when this flowchart is executed, the compressor 7, the blower fan 17, and the cooling fan 19 are stopped.
Then, when the temperature in the cooling chamber 2 becomes ─18 ° C., which is slightly higher than the set temperature, the compressor 7, the blower fan 17, and the cooling fan 19 are driven.

Next, in step S300, the temperature detected by the freezing room temperature sensor 21 (the temperature in the freezing room 2) is set to a predetermined value of 0 ° C.
It is determined whether it is lower than (first predetermined value). And
If the determination result in step S300 is NO, cooling of the freezing room 2 is continued as a standby state. On the other hand, if the decision result in the step S300 is YES, the process proceeds to a step S400, and it is determined whether or not the time counted by the timer set as the star in the step S200 has elapsed (timed) for a predetermined time (3 hours in the present embodiment). Is determined. That is, in this step S, the cooling of the freezing compartment 2 is started and 3
After a lapse of time, it is considered that frost has adhered to the freezing evaporator 11, and the process proceeds to step S500 to perform hot gas defrost control.

In step S500, the solenoid valve 16 is opened (ON) as hot gas defrosting control, and a high-temperature and high-pressure gas-phase refrigerant (hot gas) is passed through the hot gas bypass passage 15 by the compressor 7. It flows directly to the freezing evaporator 11. Thereby, the evaporator 1 for freezing is heated by the heat of the hot gas.
The frost adhering to 1 is melted, and defrosting is performed effectively. Subsequently, in step S600, it is determined whether or not to end the hot gas defrosting. Specifically, the hot gas defrosting is terminated when the temperature detected by the defrost release sensor 20 becomes higher than a predetermined temperature (3 ° C. in the present embodiment), and the solenoid valve 1
6 is closed (OFF). Then, step S70
Proceeding to 0, the timer started in step S200 is reset. When hot gas defrosting is performed, the frost naturally melts from the refrigerant upstream side of the refrigerating evaporator 11 in order. Therefore, in the present embodiment, the defrost release sensor 2
0 is located immediately downstream of the refrigerating evaporator 11,
When the frost adhering to the entire refrigeration evaporator 11 is completely melted, the hot gas defrosting can be completed.

That is, when the detected temperature of the defrost release sensor 20 (the pipe temperature immediately downstream of the freezing evaporator 11) becomes higher than 3 ° C., it is determined that the frost adhering to the freezing evaporator 11 has been sufficiently removed. You do it. By the way, in the present embodiment,
If the determination result in step S400 is NO, that is, after the freezing compartment 2 is cooled to 0 ° C. or less, the following steps S800 to 100 are performed during the above-described hot gas defrosting.
The off-cycle defrost described in FIG.

First, in step S800, it is determined whether or not the freezing room temperature detected by the freezing room temperature sensor 21 is 10 ° C. or higher. That is, this step S800
Then, at least one of the carry-out doors 4 and 5 is opened,
It is determined whether or not the temperature inside the freezing room 2 has risen to 10 ° C. (second predetermined temperature) or more due to the outside air entering the freezing room 2.

If the result of the determination in step S800 is NO, that is, if the off-cycle defrosting is performed when the temperature in the freezing compartment 2 is low as described in the means for solving the above-mentioned problems, additional processing is required. In this case, the frost adheres to the refrigerating evaporator 11, and in this case, the process returns to the step S400 without performing the off-cycle defrost. On the other hand, when the unloading doors 4 and 5 are opened and the temperature in the freezing room 2 becomes higher than 10 ° C., the process proceeds to step S900, where off-cycle defrost control is performed, and the frost adhering to the freezing evaporator 11 is removed. Frost. Note that the off-cycle defrost control in the present embodiment removes frost adhering to the refrigerating evaporator 11 by operating only the cooling fan 19 with the compressor 7 stopped. The off-cycle defrost control is performed in step S1000.
It is determined whether or not to end. In the present embodiment, after the off-cycle defrost is started in step S1000, it is continued until a predetermined time (about 120 seconds) is measured.

By doing so, the above-described off-cycle defrosting is performed when the inside of the freezer compartment 2 is cooled and the freezer compartment temperature rises from a low temperature (0 ° C.) to a predetermined temperature (10 ° C.). This makes it possible to simplify the defrosting control system for the refrigerating vehicle without providing a door switch, and to effectively perform defrosting by off-cycle defrosting. In addition,
The value of 10 ° C. is a temperature at which frost is not excessively attached to the refrigeration evaporator 11 even when the off-cycle defrost is performed, and the frost of the refrigeration evaporator can be effectively defrosted.

In the present embodiment, the defrost release sensor 2
When the temperature detected by 0 becomes higher than 3 ° C. and the frost adhering to the freezing evaporator 11 is sufficiently defrosted, the hot gas defrosting can be terminated. Therefore, in the present invention, since off-cycle defrosting is effectively performed, hot gas defrosting is performed, and the time during which the temperature of the refrigeration evaporator 11 becomes higher than 3 ° C. is reduced. As a result, it is possible to suppress a rise in the temperature in the freezing compartment 2 due to hot gas defrosting.

(Other Embodiments) In the above embodiment, the defrost release sensor 20 is attached to the refrigerant pipe 13 immediately downstream of the refrigerating evaporator 11, It may be attached to a site, for example, a fin or a tube. In the above embodiment, the off-cycle defrost is performed for a predetermined time of 2 minutes, but may be performed until the detected temperature of the defrost release sensor 20 becomes higher than 3 ° C. Also, at this time, when performing off-cycle defrost,
When the detected temperature of the defrost release sensor 20 is higher than 3 ° C., off-cycle defrost may not be performed.

Although the present embodiment has been described with reference to an example in which the present invention is applied to a refrigerator car, the present invention is not limited to a refrigerator car and can be applied to any refrigerator.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle refrigeration apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle device 3 in the embodiment.

FIG. 3 is a flowchart showing control contents of a freezing room 2 in the embodiment.

FIG. 4 is a time chart showing an operation content of the freezing room 2 in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Refrigeration car, 2 ... Freezer room, 3 ... Refrigeration cycle device, 7 ...
Compressor 8 Condenser 10 Pressure reducing device 11 Evaporator for freezing 19 Cooling fan 21 Freezer temperature sensor

Claims (5)

[Claims] 1. A compressor (7) for compressing and discharging a refrigerant at a high temperature and a high pressure, discharging the refrigerant, a condenser (8) for condensing the refrigerant compressed by the compressor (7), and a condenser (8). A decompression device (10) for decompressing the condensed refrigerant, and an evaporator (1) for evaporating the refrigerant decompressed by the decompression device (10).
1), a blower (19) for blowing air toward the evaporator (11), and a freezer of the refrigerator (1) in the evaporator (11). (2) is cooled, and the refrigerant compressed to a high temperature and a high pressure by the compressor (7) is caused to flow to the evaporator (11), so that the frost adhered to the evaporator (11). Hot gas defrosting for defrosting the refrigeration cycle (3) and the blower (19)
A defrosting control device for a refrigerator having defrosting control means (6) for controlling in conjunction with off-cycle defrosting for defrosting frost adhering to the evaporator (11) by operating the evaporator (11). An indoor temperature detecting means (21) for detecting an indoor temperature of the freezing room (2) is provided, and the defrost control means (6) is configured such that the indoor temperature detected by the indoor temperature detecting means (21) is a first predetermined temperature When the room temperature detected by the room temperature detecting means (21) becomes higher than a second predetermined temperature higher than the first predetermined temperature after the temperature has reached, the off-cycle defrosting is performed for a predetermined time. Defrosting control device for refrigerator. 2. A cooling signal generating means (24) for generating a signal for cooling a freezer compartment in the evaporator, wherein the defrosting control means (6) controls the cooling signal generating means (24). The defrost control device for a refrigerator according to claim 1, wherein the off-cycle defrost is performed for a predetermined time when a signal for cooling the freezer (2) is generated. 3. A configuration in which the hot gas defrosting is performed when a predetermined time period elapses while a signal for cooling the freezer compartment (2) is generated by the cooling signal generating means (24). The defrosting control device for a refrigerator according to claim 1 or 2, wherein: 4. An off-cycle defrost is started, and there is provided a timer (1000) for measuring a time during which the off-cycle defrost is being performed, and the timer (1000) measures a predetermined time. When,
The defrost control device for a refrigerator according to any one of claims 1 to 3, wherein the off-cycle defrost is terminated. 5. An evaporator temperature detecting means (20) for detecting a physical quantity corresponding to a refrigerant temperature downstream of the evaporator (11) is provided near the evaporator (11). The refrigerator according to any one of claims 1 to 4, wherein the hot gas defrosting is terminated when a temperature of the evaporator (11) detected by the means (20) becomes higher than a predetermined temperature. Defrost control device.