JPH07111277B2 - Refrigeration system operation controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a refrigerating machine provided in a refrigerating container or the like, and particularly to a measure for reducing the capacity of a compressor.

(Prior Art) Conventionally, as an operation control device for this type of refrigeration system,
For example, there is one disclosed in JP-A-63-46360.

That is, a hot gas bypass line that bypasses the condenser and the expansion valve while configuring a refrigerant circulation circuit by sequentially connecting a compressor with an adjustable capacity, a condenser, an expansion valve with an adjustable opening degree, and an evaporator When the heat load fluctuates and the temperature inside the storage chamber becomes higher than a predetermined temperature range set with a predetermined width with respect to a desired temperature inside the storage chamber, the capacity of the compressor is increased and the opening degree of the expansion valve is increased. Is controlled so that the internal temperature falls within a predetermined temperature range. When the temperature inside the refrigerator is within the predetermined temperature range, the amount of hot gas flowing through the hot gas bypass line is controlled so that the temperature inside the refrigerator converges to the set temperature inside the refrigerator.

(Problems to be Solved by the Invention) In the capacity control device of the refrigeration apparatus described above, conventionally, when trying to reduce the capacity of the compressor from the steady operation state, the refrigerant liquid amount flowing through the liquid line of the refrigerant circulation circuit and the hot The amount of hot gas flowing through the gas bypass line must be detected at the same time, which makes control difficult.

Therefore, there is one in which an electronic expansion valve is used to control the refrigerant circulation amount in the refrigerant circulation circuit so that the internal cold storage temperature becomes a predetermined temperature.

However, in this case, since the opening degree of the electronic expansion valve is controlled separately from the capacity of the compressor, once the number of capacity stages of the compressor increases, the internal heat load decreases due to the decrease of the outside air temperature. However, there is a problem that the power consumption of the compressor is large because the compressor continues to operate at a high capacity. Also, since the amount of liquid refrigerant is controlled by controlling the electronic expansion valve, if the heat load decreases, the electronic expansion valve will be throttled while the capacity of the compressor remains large, so the evaporation temperature of the refrigerant in the evaporator will be reduced. Will decrease and the amount of frost will increase. Further, there is a problem that the temperature distribution of the evaporator is deteriorated due to the uneven flow, and the temperature distribution of blown air is deteriorated.

The present invention has been made in view of such a point, and when the expansion valve is continuously at a low opening for a predetermined time, the capacity of the compressor is decreased or the amount of intake gas is decreased to reduce the heat load. The purpose is to reduce power consumption and prevent an increase in the amount of frost so that the amount of frost can be reduced.

(Means for Solving the Problems) In order to achieve the above object, the means taken by the invention according to claim (1) is, as shown in FIG. 1, first, a compressor (1) whose capacity is adjustable. , A condenser (3), a refrigerant circulation circuit (11) in which an expansion valve (4) with adjustable opening and an evaporator (5) are sequentially connected, and the opening of the expansion valve (4) is controlled. Expansion valve control means (14) is provided.

An opening degree detecting means (8) for detecting the opening degree of the expansion valve (4) is provided, while the opening degree of the expansion valve (4) is changed by receiving a detection signal from the opening degree detecting means (8). A capacity reducing means (15) is provided for reducing the capacity of the compressor (1) when it is continued for a predetermined time in a state of being less than a preset opening degree.

The means taken by the invention according to claim (2) is a compressor (1), a condenser (3), and an expansion valve (4) with adjustable opening.
Refrigerant circulation circuit (1
1) and expansion valve control means (14) for controlling the opening of the expansion valve (4).

The intake gas amount adjusting means (6) provided between the evaporator (5) and the compressor (1) for adjusting the intake gas amount of the compressor (1) and the expansion valve (4). An opening detection means (8) for detecting the opening is provided, and while the opening of the expansion valve (4) is below a predetermined value set in advance in response to a detection signal of the opening detection means (8). A structure is provided with a capacity reducing means (16) for controlling the suction gas amount adjusting means (6) so as to reduce the suction gas amount of the compressor (1) when continuing for a predetermined time.

Further, the means taken by the inventions according to claims (3) and (4) is the operation control device for a refrigerating apparatus according to claim (1) or (2), in which the capacity reducing means (15) and (16) are When the internal temperature is within a predetermined temperature range having a predetermined value with respect to the set temperature, the expansion valve (4) is configured to operate when the opening degree of the expansion valve (4) is equal to or less than the set opening degree for a predetermined time. ,
The means taken by the invention according to claim (5) is the operation control device for a refrigerating apparatus according to claim (3) or (4),
Evaporator (5) controls the internal temperature of the capacity reducing means (15), (16)
It is set to the blown air temperature.

Further, the means taken by the invention according to claim (6) is the operation control device for a refrigerating apparatus according to claim (2), wherein the intake gas amount adjusting means (6) is an intake solenoid valve (6a), It is composed of a capillary (6b) connected in parallel to the intake solenoid valve (6a).

(Operation) With the above configuration, in the invention according to claim (1), for example, during the refrigerating operation, the expansion valve control means (14) controls the opening degree of the expansion valve (4) to control the refrigerant circulation amount. , The temperature inside the refrigerator is converged to the set temperature.

On the other hand, when the heat load decreases and the opening degree of the expansion valve (4) becomes a predetermined value, for example, 50% or less, and this low opening degree continues for a predetermined time, the compressor (1) is reduced by the capacity reducing means (15). Reduce the capacity and adjust the compressor (1) capacity to match the heat load.

In the invention according to claim (2), the heat load is reduced,
When the opening of the expansion valve (4) equal to or less than a predetermined value continues for a predetermined time, the capacity reducing means (16) controls the intake gas amount adjusting means (6), and specifically, in the invention according to claim (6), The suction solenoid valve (6a) is closed and the suction gas is stored in the capillary (6b).
The amount of gas sucked into the compressor (1) is reduced so as to flow through the compressor (1) to reduce the capacity of the compressor (1).

Further, in the inventions according to claims (3) and (4), the capacity reducing means (15) and (16) are the temperature inside the refrigerator, specifically, in the invention according to claim (5), the blowout of the evaporator (5). The air temperature is within a predetermined temperature range, and it operates in a stable state.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

An embodiment of the invention according to claim (1) is shown in FIG.

In the figure, (A) is a refrigerating device installed in a refrigerating container, (1) is a compressor with unloading capacity that can be changed to 33%, 67%, and 100%, and (3) is an air-cooling fan (F1). And a condenser equipped with a motor (MF1), (18) a receiver, (4) a PID-controlled electronic expansion valve, (5) a fan (F2) inside the compartment and a motor (MF2) attached Evaporator, (9) is an accumulator, each device (1),
(3), (18), (4), (5), (19) are connected in series by the refrigerant pipe (20) in the above-mentioned order to form the refrigerant circulation circuit (11) and compress the refrigerant. By circulating the refrigerant circulation circuit (11) with the machine (1), the heat of the refrigerant gas is released to the outside of the refrigerator in the condenser (3) to liquefy the refrigerant gas and to the evaporator (5). The refrigerant gas is vaporized to absorb the heat in the refrigerator, thereby cooling the inside of the refrigerator.

Further, (2) is a three-way proportional valve interposed between the compressor (1) and the condenser (3), and (10) has one end connected to the three-way proportional valve (2) and the other. A hot gas bypass line whose end bypasses the condenser (3), the receiver (18) and the electronic expansion valve (4) and is connected to the suction side refrigerant pipe (12) of the evaporator (5). The gas bypass line (10) includes a drain pan heater section (13). Further, (Th1) and (Th2) are refrigerant temperature sensors for detecting the inlet refrigerant temperature and the outlet refrigerant temperature of the evaporator (5),
(Th3) and (Th4) are air temperature sensors for detecting the intake air temperature and the blown air temperature (internal temperature) of the evaporator (5).

Then, the temperature sensors (Th1), (Th2), (Th
The detection signals of 3) and (Th4) are configured to be input to the controller (21) as shown in FIG. 3, and the controller (21) includes an A / D converter (23). , I / 0 port (24), RAM (25), ROM (26) and CPU (27). The controller (21) has an opening detection means (8) for detecting the opening of the electronic expansion valve (4).
Is provided, and the motor (MEV) of the electronic expansion valve (4) is controlled so as to have a predetermined superheat degree based on the detection signals of the refrigerant temperature sensors (Th1) and (Th2) during the refrigerating operation.
While performing ID control, during the refrigerating operation, the blown air temperature falls within a predetermined temperature range (± 5 ° C relative to the set temperature) based on the detection signal of the blown air temperature sensor (Th4) of the evaporator (5). PID the motor (MEV) of the electronic expansion valve (4)
Expansion valve control means (14) for controlling is included. Also,
The controller (21) includes hot gas control means (17) for controlling the amount of hot gas bypass by PID controlling the motor (MV) of the three-way proportional valve (2) during defrost operation.

Further, the controller (21) is provided with a compressor capacity control means (7) for increasing and controlling the compressor capacity in response to an increase in heat load. In addition, the controller (21) receives a signal from the opening detection means (8),
When the temperature of the air blown from the evaporator (5) is within the predetermined temperature range, the opening of the electronic expansion valve (4) is kept at a predetermined value, for example 50% or less, for a predetermined time, for example 20 minutes A capacity reducing means (15) for reducing the capacity of (1) is included.

Furthermore, in FIG. 3, (Tr) is a transformer, (S) is a start / stop switch, (31) is a high pressure switch, (32)
Is a low pressure switch, (33) is a hydraulic protective pressure switch, (3
4) is a lamp switch, (35) is a hydraulic reset switch, (36) is a compressor protection thermoswitch, (37) is for switching the transformer (Tr) wiring, (38) is for voltage switching, (39),
Reference numeral (40) is a manual switching switch for the compressor motor, and the switches (37) to (40) are all interlocked.

(MC) is a compressor motor, and (10c) is a normally open contact (10C-1) that allows the blower fan motor (MF1) of the condenser (3) to be energized while operating the compressor motor (MC). )
Compressor relay (10F) is a normally open contact (10F-1) that operates the fan motor (MF2) of the evaporator (5)
Evaporator fan relay, with (20S) refrigerant pipe (1
It is a solenoid valve relay that allows or blocks the flow of refrigerant in 2).

Next, regarding the operation control operation of the refrigeration system (A),
A description will be given based on the control flow in the figure.

First, in step ST1, when the refrigeration system (A) is in a steady operation state and, for example, the compressor (1) is operating at 100% capacity, the process proceeds to step ST2 and the evaporator (5)
It is determined whether or not the blown air temperature of is within a predetermined temperature range within ± 0.5 ° C with respect to the set temperature in the refrigerator, and if it is out of the range, the process proceeds to step ST3, and the expansion valve control means (14) The electronic expansion valve (4) is PID-controlled to return to step ST2 so that the blown air temperature falls within a predetermined temperature range. On the other hand, in step ST2, when the blown air temperature is within the predetermined range, the process proceeds to step ST4, and it is determined whether the opening degree of the electronic expansion valve (4) is 50% or less according to the detection signal of the opening degree detection means (8). Is determined. And the opening degree of the electronic expansion valve (4) is 50
If it is larger than%, the process returns to step ST2 and the above operation is repeated.

On the other hand, in step ST4, when the opening degree of the electronic expansion valve (4) is 50% or less, the process proceeds to step ST5, the timer is started and the process proceeds to step ST6, and it is determined whether or not the timer counts up. To be done. This timer is set to, for example, 20 minutes, and until this 20 minutes has elapsed, the process proceeds to step ST7 and the opening degree of the electronic expansion valve (4) is set to 50.
% Or less. If it is 50% or less, the process proceeds to step ST6, and it is determined whether the low opening of 50% or less continues for 20 minutes or more. And before 20 minutes have passed, the valve opening is
When it becomes more than%, after moving to step ST8 and clearing the timer, it returns to step ST2 and returns to the normal refrigerant control operation described above.

When the low opening of 50% or less continues for 20 minutes, the step
The process moves from ST6 to step ST9, and the capacity reducing means (15) reduces the capacity of the compressor (1) to 67% and returns to step ST2.

That is, when the capacity of the compressor (1) is operating at 100% and the capacity is large, the capacity is reduced.

After that, although not shown, even when operating at 67%, control is performed in the same manner as steps ST1 to ST9 above, and if the opening of the electronic expansion valve (4) continues for 20 minutes at a low opening of 50% or less, step ST
At 9, reduce the capacity of the compressor (1) to 33%.

Therefore, the heat load is reduced and the opening degree of the electronic expansion valve (4) is 50
%, The capacity of the compressor (1) is reduced if it is continued for 20 minutes, so that the compressor (1) at low heat load
Since high capacity operation can be prevented, power consumption can be reduced and frost formation on the evaporator (5) can be suppressed, and deterioration and loss of foodstuffs in the storage due to water evaporation can be prevented. .

FIG. 5 shows an embodiment of the invention according to claim (2). In this embodiment, the capacity reducing means (15) of the previous embodiment directly reduces the capacity of the compressor (1). Instead, the suction gas adjusting means (6) is provided downstream of the evaporator (5) and between the accumulator (19) and the compressor (1).

The suction gas adjusting means (6) has a suction electromagnetic valve (6a) interposed in the refrigerant circulation circuit (11), bypasses the electromagnetic valve (6a), and is parallel to the electromagnetic valve (6a). (6
b) is connected to the intake solenoid valve (6a).
Is opened and closed by the capacity reducing means (16).

That is, the capacity reducing means (16) closes the suction solenoid valve (6a) when the opening degree of the electronic expansion valve (4) is kept at a predetermined value or less and continues for a predetermined time, and the refrigerant has a large flow resistance in the capillary ( 6b), the intake gas amount of the compressor (1) is reduced, and the compressor capacity is reduced.

FIG. 6 shows a control flow of this embodiment. First, in step ST1 as in the previous embodiment, for example, when the compressor (1) is continuously operated, it operates in the same manner as step ST2 to step ST8, and electronic expansion is performed. Valve (4) can be set to a low opening of 50% or less
After continuing for 20 minutes, the process proceeds from step ST8 to step ST12, the suction solenoid valve (6a) is closed, and the refrigerant is cooled by the capillary (6
The amount of gas sucked into the compressor (1) is reduced by flowing b) to reduce the refrigeration capacity.

Other configurations and operations are similar to those of the previous embodiment.

In this embodiment, the capacity of the compressor (1) is switched to three stages, but it may be switched to two stages, four stages, etc. Similarly, the intake gas amount adjusting means (6) has three stages or more. You may switch to.

Furthermore, the invention according to claim (1) and the invention according to claim (2) may be used together to control both the compressor capacity and the intake gas amount.

(Effects of the Invention) As described above, according to the inventions according to claims (1) and (2), when the low opening degree of the expansion valve continues for a predetermined time, the capacity of the compressor is reduced. When the internal heat load capacity is reduced, the compressor capacity can be easily reduced without adversely affecting the refrigerant circulation circuit and the internal temperature, so that the power consumption is lower than that in the conventional technology. Since it is possible to prevent a decrease in the evaporation temperature of the refrigerant in the evaporator, it is possible to prevent the formation of frost, and to prevent the foodstuffs in the refrigerator from being depleted and deterioration caused by dehydration. You can In addition, since it is possible to prevent uneven temperature distribution in the evaporator due to uneven flow, there is no adverse effect on the temperature distribution inside the refrigerator, and economical and favorable freezing, refrigerating, and cold keeping can be performed.

Further, according to the inventions according to claims (3) to (5), the capacity of the compressor or the amount of suction gas is reduced in a state where the inside of the refrigerator is stable, so that the refrigerant circulation circuit and the temperature inside the refrigerator are adversely affected. Can be reliably prevented.

Further, according to the invention of claim (6), since the intake gas amount adjusting means is composed of the intake solenoid valve and the capillary,
The simple structure enables reliable operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention, FIG. 2 is a refrigerant circuit diagram of a refrigerating apparatus, FIG. 3 is an electric circuit diagram thereof, and FIG. 4 is a control flow chart thereof. FIG. 5 is a refrigerant circuit diagram showing another embodiment, and FIG. 6 is a control flow chart thereof. (1) ... compressor, (2) ... adjusting means, (3) ... condenser, (4) ... electronic expansion valve, (5) ... evaporator,
(6) ... intake gas amount adjusting means, (6a) ... intake solenoid valve, (6b) ... capillary, (7) ... compressor capacity control means, (8) ... opening degree detection means, (11 ) ... Refrigerant circulation circuit, (14) ... Expansion valve control means, (15) ... Capacity reduction means, (16) ... Capacity reduction means.

Claims (6)

[Claims] 1. A refrigerant circulation circuit (11) in which a compressor (1) with adjustable capacity, a condenser (3), an expansion valve (4) with adjustable opening and an evaporator (5) are sequentially connected. ) And expansion valve control means (14) for controlling the opening of the expansion valve (4)
And an opening degree detecting means (8) for detecting the opening degree of the expansion valve (4), and the opening degree of the expansion valve (4) is preset in response to a detection signal from the opening degree detecting means (8). An operation control device for a refrigerating apparatus, comprising: a capacity reducing means (15) for reducing the capacity of the compressor (1) when the operation is continued for a predetermined time in a state of not more than the opening degree. 2. A refrigerant circulation circuit (11) in which a compressor (1), a condenser (3), an expansion valve (4) with adjustable opening and an evaporator (5) are sequentially connected, and the expansion. It is provided between the expansion valve control means (14) for controlling the opening degree of the valve (4) and the evaporator (5) and the compressor (1) to adjust the intake gas amount of the compressor (1). Intake gas amount adjusting means (6), opening detecting means (8) for detecting the opening of the expansion valve (4), and an expansion valve (4) receiving a detection signal of the opening detecting means (8). The capacity reducing means (16) for controlling the intake gas amount adjusting means (6) so as to reduce the intake gas amount of the compressor (1) when the opening degree of the compressor continues for a predetermined time in a state of being equal to or less than a preset predetermined value. An operation control device for a refrigeration system, comprising: 3. The operation control device for a refrigerating apparatus according to claim 1, wherein the capacity reducing means (15) is in a state in which the internal temperature is within a predetermined temperature range having a predetermined width with respect to the set temperature. An operation control device for a refrigerating apparatus, which is configured to reduce the capacity of the compressor (1) when the expansion valve (4) is opened for a predetermined time or longer in a state where the opening is less than a set opening. 4. The operation control device for a refrigerating machine according to claim 2, wherein the capacity reducing means (16) is in a state in which the internal temperature is within a predetermined temperature range having a predetermined width with respect to the set temperature. When the opening degree of the expansion valve (4) is equal to or smaller than the set opening degree and continues for a predetermined time, the suction gas amount adjusting means (6) is controlled so as to reduce the capacity of the compressor (1). An operation control device for a refrigeration system, which is characterized in that: 5. The operation control device for a refrigerating apparatus according to claim 3 or 4, wherein the internal cold storage temperature, which is set as a reference by the capacity reducing means (15), (16), is the air blown out from the evaporator (5). An operation control device for a refrigeration system, which is a temperature. 6. The operation control device for a refrigerating apparatus according to claim 2, wherein the intake gas amount adjusting means (6) is connected in parallel to the intake solenoid valve (6a) and the intake solenoid valve (6a). An operation control device for a refrigeration system, which is configured with a capillary (6b).