JP2745836B2 - Operation control device for refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a refrigeration system, and more particularly to control measures for a defrost operation.

[0002]

2. Description of the Related Art Generally, a refrigerating apparatus of this type includes a refrigerant pipe, a compressor, a condenser, an expansion valve, and an evaporator in that order, as disclosed in Japanese Patent Application Laid-Open No. Sho. Are connected to each other. In this refrigeration apparatus, when the operation time continues for a predetermined time, the defrost operation is performed by flowing hot gas to the evaporator by a defrost timer, and when the intake gas temperature of the compressor reaches the predetermined temperature, the defrost operation is terminated. ,
This defrosting operation removes frost from the evaporator and prevents a decrease in refrigeration capacity.

[0003]

In the above-mentioned refrigerating apparatus, the defrost operation is terminated by the temperature of the intake gas of the compressor. Therefore, when the outside air temperature is high, the defrost operation is completed in a relatively short time. However, when the outside air temperature is low, there is a problem that it takes a long time. In other words, in the case of a low outside air temperature, the amount of heat released to the outside air from the refrigerant circulation circuit increases, and the amount of heat supplied to the defrost decreases. As a result, the rising speed of the intake gas temperature is reduced, and the defrost operation time is lengthened.

[0004] In addition, in the case of a low outside air temperature, for example, the amount of generated water in a refrigerator, which is a refrigeration container, is small and ventilation is not performed, so that the amount of frost is generally small. However, when the defrost operation is performed for a long time as described above, the amount of heat released at the time of the defrost operation is consumed in addition to melting the frost of the evaporator and the drain pan, for example, is spent on the temperature rise of the frame of the refrigeration container. Further energy is required to cool the frame or the like whose temperature has risen again.

[0005] These problems become remarkable especially in the refrigerating mode. That is, in the refrigeration mode, the temperature of the frost or ice and the temperature of the frame are usually low, so that the temperature difference between the set temperature of the thermosensor that detects the end of the defrost operation and the temperature of the frost or the like increases. .

Accordingly, when the outside air temperature is low, there is a problem that the defrost operation becomes unnecessarily long, resulting in an increase in power consumption and an excessive rise in the internal temperature, which leads to a rise in the temperature of cargo items and the like. .

Conventionally, in the above defrost operation, the compressor is operated at full load regardless of the outside air temperature. When the outside air temperature is high, the discharge gas temperature of the compressor is high. In many cases, there has been a problem that defrosting is completed early due to the shape of the frost and the structure of the evaporator. That is,
Since the discharge gas temperature is high, the frost is rapidly melted only in the portion of the evaporator that is in contact with the fins, creating a ventilation space through which the air flows, and the discharge gas temperature of the evaporator rises, and the upper part of the evaporator rises. There is a problem that the defrosting is ended while leaving the frost, and a residual frost is generated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent an increase in power consumption during defrost operation, to prevent an excessive rise in temperature, and to prevent residual frost. It is intended for.

[0009]

In order to achieve the above-mentioned object, a means taken by the present invention is to detect an operation time of a compressor between a defrost operation and a next defrost operation,
When the operating time is equal to or shorter than a predetermined value, the defrost operation time is shortened, while the compressor capacity during the defrost operation is changed according to the operating time of the compressor.

More specifically, as shown in FIG. 1, means taken by the invention according to claim 1 includes a compressor (11), a condenser (12), an expansion mechanism (EV), and an evaporator. Tableware (14)
And a refrigeration apparatus provided with a refrigerant circulation circuit (1) in which are connected in order.

An operation detecting means (21) for detecting the operation of the compressor (11) is provided. Further, upon receiving the operation signal of the compressor (11) output from the operation detecting means (21), the operation time of the compressor (11) from the previous defrost operation to before the current defrost operation is integrated, and Operating time calculating means for calculating an operating time of the compressor (11) by calculating a ratio of an operating time at the time of pull-down after the defrost operation to the integrated time larger than a ratio of an operating time at the time of in-range after the pull-down operation; (22) is provided. In addition, upon receiving the calculation signals the operating time calculating means (22) outputs, calculates
If the operating time exceeds the specified value,
Until the maximum time of the defrost operation elapses.
When the lost operation is continued, the defrost operation is terminated.
On the other hand, if the calculated operation time is equal to or shorter than a predetermined value, a time ending means (23) for terminating the current defrost operation after a predetermined time shorter than the maximum time elapses is provided.
Is provided .

[0012] Further, the means taken by the invention according to claim 2 is the compressor according to claim 1, wherein
Gas temperature detection means (Th
5) and a temperature ending means (24) for terminating the defrost operation when the temperature of the intake gas during the defrost operation reaches a predetermined temperature in response to the temperature signal output from the suction gas temperature detection means (Th5). Are provided.

The means adopted by the invention according to claim 3 is a means for terminating the passage of time according to the invention described in claim 1 (2).
Instead of 3), upon receiving the calculation signal output from the operating time calculating means (22), if the calculated operating time is larger than a predetermined value, the compressor capacity during defrost operation is reduced to a low capacity, and In this case, a capacity setting means (25) for setting the compressor capacity during defrost operation to a high capacity is provided.

[0014]

According to the first aspect of the present invention,
The refrigerant circulates through the refrigerant circuit (1), cools the air sucked in the evaporator (14) and blows out the cooling air, and discharges the hot gas during the defrost operation to the evaporator (14).
To remove frost.

When the compressor (11) operates, the operation detecting means (21) detects the operation of the compressor (11) and outputs an operation signal. This operation detecting means (2
In response to the operation signal of 1), the operation time calculating means (22) accumulates the operation time of the compressor (11) from after the previous defrost operation to before this defrost operation. Further, the operating time calculating means (22) calculates the operating time of the compressor (11) by making the ratio of the operating time at the time of pull-down to the integrated time larger than the ratio of the operating time at the time of in-range.

Subsequently, upon receiving the calculation signal output from the operating time calculating means (22), the calculated operating time exceeds a predetermined value.
The maximum time for defrost operation has elapsed
When the defrost operation continues, the aging end means (23)
Terminate the above defrost operation, for example, defrost operation
Rolling is completed in a maximum of 90 minutes. On the other hand, if the calculated operation time is equal to or shorter than the predetermined value, the aging end means (23) ends the defrost operation after the elapse of the predetermined time shorter than the maximum time , for example, ends the defrost operation in 45 minutes.

Further, in the invention according to claim 2, the suction gas temperature of the compressor (11) is detected by a suction gas temperature detecting means (Th).
5) and the suction gas temperature detecting means (Th
When the temperature of the intake gas reaches a predetermined temperature in response to the temperature signal of 5), the temperature termination means (24) terminates the defrost operation. That is, if the calculated operating time is longer than the predetermined value, the temperature ending means (24) ends the defrost operation.

According to the third aspect of the present invention, there is provided the first aspect.
Utilizing the calculation signal of the operating time calculating means (22) in the invention, the capacity setting means (25) determines that the outside air temperature is high when the calculated operating time is longer than a predetermined value, and reduces the compressor capacity to a low capacity. On the other hand, if the calculated operation time is equal to or less than the predetermined value, it is determined that the outside air temperature is low, and the compressor capacity is set to a high capacity. In other words, when the outside air temperature is high, defrosting is performed slowly to completely remove frost.

[0019]

Therefore, according to the first aspect of the present invention,
The operation time of the compressor (11) between the defrost operation and the next defrost operation is calculated, and when the calculated operation time is equal to or less than a predetermined value, the defrost operation is switched to the maximum defrost operation.
When the defrost load is low at a low outside air temperature, the defrost operation time can be shortened, so that the power consumption can be reduced and the air temperature can be reduced. An excessive rise can be prevented, and an excessive rise in the temperature of a cargo item or the like can be reliably prevented.

According to the second aspect of the present invention, when the temperature of the intake gas of the compressor (11) reaches a predetermined temperature, the defrost operation is terminated. Therefore, when the defrost load is large, the defrost operation is performed for a required time. And defrosting can be performed reliably.

In the invention according to claim 3, the compressor capacity during the defrost operation is set to a low capacity when the calculated operation time between the defrost operations is larger than a predetermined value, and the compressor capacity is set to a high capacity when the calculated operation time is small. In addition, the defrost time can be reduced at a low outside air temperature. On the other hand, since the defrosting is performed slowly at a high outside air temperature, the frost formation of the evaporator (14) is gradually melted, and the frost formation can be completely removed. Can be prevented.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 2, (1) is a refrigerant circulation circuit of a refrigerating device provided in a refrigerating container, which cools the inside of a container body (not shown).

The refrigerant circuit (1) includes a compressor (11) having a variable capacity, a condenser (12), and a receiver (13).
, An electric expansion valve (EV) as an expansion mechanism, and an evaporator (1).
4), an accumulator (15), and a suction solenoid valve (SV) having a bleed port in order of a refrigerant pipe (16).
To form a closed circuit. And
The condenser (12) is provided with an external fan (12a), and the evaporator (14) is provided with an internal fan (14a), while the compressor (11) and the condenser (12) are connected to each other. A three-way solenoid valve (TV) is interposed between them. One end of a hot gas bypass passage (17) is connected to the three-way solenoid valve (TV), and the other end of the hot gas bypass passage (17) is connected between the electric expansion valve (EV) and the evaporator (14). And a drain pan heater (17a) is formed. The hot gas bypass path (17) supplies hot gas from the compressor (11) to the evaporator (14) during the defrost operation, and melts frost on the evaporator (14) and the drain pan (not shown). It is configured as follows.

The refrigeration system is provided with various sensors, (HPS) a high pressure sensor for detecting the high pressure refrigerant pressure on the discharge side of the compressor (11), and (Th1) an evaporator (14). (Th2) is a gas pipe temperature sensor that detects the gas pipe temperature at the outlet side of the evaporator (14), and (Th3) is the evaporator (1).
4) a suction temperature sensor for detecting the temperature of the suction air on the air suction side, (Th4) a blow temperature sensor for detecting the temperature of the blown air on the air blow side of the evaporator (14), and (Th5) a compressor (11). Is a suction pipe temperature sensor as suction gas temperature detecting means for detecting a suction gas temperature on a suction side of the suction pipe.

The above sensors (HPS), (Th
The detection signals of (1) to (Th5) are input to the controller (2), and the controller (2)
1), electric expansion valve (EV), intake solenoid valve (SV) and 3
It is configured to control a one-way solenoid valve (TV) and the like.
That is, the controller (2) controls the electric expansion valve (E
V) in the refrigerating mode, PID control is performed based on the degree of superheat based on the detection signals of the liquid pipe temperature sensor (Th1) and the gas pipe temperature sensor (Th2), and in the refrigerating mode, the blowout is performed based on the detection signal of the blowout temperature sensor (Th4). While the PID control is performed based on the air temperature, when the evaporation temperature of the intake solenoid valve (SV) decreases, for example, the control is performed such that the motor-operated expansion valve (EV) is closed when a predetermined opening degree continues for a certain period of time. Further, in the freezing mode, the controller (2) controls the internal temperature, that is, the suction temperature sensor (Th3).
The ON / OFF control of the compressor (11) is performed so that the suction air temperature detected by the compressor becomes a set value.

The controller (2) has a defrost timer (T1) and a defrost end timer (T
2) is provided, and an operation detecting means (21) of the compressor (11), an operating time calculating means (22), a time ending means (23), and a temperature ending means (24) are configured. I have. The defrost timer (T1) detects an interval of the defrost operation. For example, the controller (2) controls the three-way solenoid valve (TV) so that the defrost operation is performed every 12 o'clock by the defrost timer (T1). ing. The end timer (T2) detects the defrost operation time, and the operation detection means (21)
Is configured to detect the operation of the compressor (11), that is, the ON state.

The operating time calculating means (22) is a feature of the present invention, and is configured to calculate the operating time between the defrost operation in the refrigeration mode and the next defrost operation. . That is, as shown in FIG. 3, in the refrigerating mode, the compressor (11) is turned on and operated when the differential throttling operation is completed (see FIG. 3A), and when the internal temperature reaches the set value, the compressor (11) is turned on. Stop). Thereafter, when the internal temperature reaches the upper limit of the in-range, the compressor (11) is operated again (see FIG. 3B1), and when the internal temperature reaches the set value, the compressor (11) is stopped again. The operating time calculating means (22) integrates the operating time (A
+ B1 + B2 +... + Bn) and the operating time ratio β is calculated based on the following equation.

[0029] In the above equation, the reason why the constant α is provided is that the amount of frost is large at the time of pull-down, and the ratio of the operation time A during the pull-down is calculated to be larger than the ratio of the operation time B during the subsequent in-range.

When the operating time ratio β calculated by the operating time calculating means (22) is equal to or less than a predetermined value, for example, 0.2 or less, the ending timer (T2) sets the ending timer (T2) to a predetermined time. For example, the configuration is such that the defrost operation is terminated at 45 minutes. The termination timer (T
2) detects the maximum during the normal defrost operation. For example, at 90 minutes, the controller (2) forcibly ends the defrost operation, and when the operation time rate β is equal to or less than the predetermined value, Since the compressor (11) is not operating so much, the defrost load is small at a low outside air temperature, and the defrost operation is terminated in a reduced time (45 minutes).

The temperature termination means (24) is configured to terminate the defrost operation when the suction pipe temperature sensor (Th5) reaches a predetermined temperature, for example, 40 ° C. When the temperature is equal to or more than the predetermined value, the defrost operation is terminated by the temperature termination means (24).

Next, the operation of the refrigeration system will be described.

First, the refrigerant discharged from the compressor (11) is condensed by the condenser (12), expanded by the electric expansion valve (EV), and then evaporated by the evaporator (14) to the compressor (11). Returning, while cooling the inside of the container body, at the time of defrost operation, the three-way solenoid valve (TV) is switched so that hot gas flows from the compressor (11) to the hot gas bypass path (17) and is supplied to the evaporator (14). To defrost.

On the other hand, in the refrigerating mode, the compressor (11) is turned ON / OFF to control the suction temperature sensor (Th).
The suction air temperature detected in 3), that is, the inside temperature is set to a set value.

Next, the control of the defrost operation will be described based on the control flow of FIG.

First, in step ST1, the operation detecting means (21) detects the operation of the compressor (11).
Subsequently, the process proceeds to step ST2, where the operation detecting means (2
In response to the operation signal of 1), the operation time calculating means (22) calculates the operation time rate β based on the equation. That is, FIG.
As shown in the above, the operating time from the previous defrost operation to before the current defrost operation is integrated, and the operating ratio at the time of pull-down is calculated to be larger than the operating time ratio at the subsequent in-range, and the above is calculated. The operation time ratio β is calculated.

Thereafter, the operation proceeds to step ST3, in which the time ending means (23) determines whether or not the operation time ratio β is equal to or less than a predetermined value. Moving to ST4, when the end timer (T2) reaches a predetermined time, for example, 45 minutes, the defrost operation is ended.

If the operation time ratio β is equal to or more than the predetermined value in step ST3, the determination is NO, and the process proceeds to step ST5, where the suction gas temperature detected by the suction pipe temperature sensor (Th5) reaches the predetermined temperature. Temperature ending means (24) ends the defrost operation.

Accordingly, the operation time rate β of the compressor (11) between the defrost operation and the next defrost operation is calculated, and when the calculated operation time rate β is equal to or less than a predetermined value, the defrost operation is switched to the maximum defrost operation. When the defrost load is small at a low outside air temperature, the defrost operation time can be shortened, so that the power consumption can be reduced and the temperature inside the refrigerator can be reduced. As a result, it is possible to prevent the cargo item temperature from excessively rising.

When the suction gas temperature of the compressor (11) reaches a predetermined temperature, the defrost operation is terminated. Therefore, if the defrost load is large, the defrost operation is performed for a necessary time, so that the defrost operation is performed reliably. Can be.

As shown by the dashed line in FIG. 2, the controller (2) is provided with a capacity setting means (25), and the capacity setting means (25) is provided with the operating time calculating means (22). ), The capacity of the compressor (11) during the defrost operation is set based on the operating time ratio β of the compressor (11). That is, if the operating time ratio β is larger than the predetermined value, it is determined that the outside air temperature is high, and the capacity of the compressor (11) is set to a high capacity full load. On the other hand, when the operating time ratio β is equal to or less than the predetermined value, it is determined that the outside air temperature is low and the compressor (11)
Set the capacity of the to low capacity unload.

The control operation of the capacity setting means (25) will be described with reference to FIG.

In FIG. 5, steps ST11 to ST13 are performed in the same manner as steps ST1 to ST3 of the previous embodiment, and after the operation detecting means (21) detects the operation of the compressor (11), the operation time is calculated. Means (2
2) calculates the operating time rate β, and determines whether the operating time rate β is greater than a predetermined value. If the operation time ratio β is larger than the predetermined value, the process proceeds from step ST13 to step ST14, and the capacity of the compressor (11) during the defrost operation is set to unload (low capacity). That is, since the operation time of the compressor (11) is long, it is determined that the outside air temperature is high, and the frost formation on the evaporator (14) is slowly defrosted.

On the other hand, if the operation time ratio β is equal to or less than the predetermined value in step ST13, the determination is NO, and the process proceeds to step ST15, where the capacity of the compressor (11) in the defrost operation is set to full load (high capacity). I do. That is, since the operation time of the compressor (11) is short, it is determined that the outside air temperature is low, and the evaporator (14)
Frost is quickly removed.

Therefore, the compressor capacity during the defrost operation is set to unload when the calculated operation time during the defrost operation is larger than the predetermined value, and the compressor capacity is set to full load when the calculated operation time is smaller than the predetermined value. Can be shortened. On the other hand, since the defrosting is performed slowly at a high outside air temperature, the frost formation of the evaporator (14) is gradually melted, and the frost formation can be completely removed. Can be prevented.

In this embodiment, the operating time calculating means (22) calculates the operating time ratio β, but the operating time (α ·
A + B), and the constant α is not limited to the embodiment, and may be a predetermined value of 1 or more (α> 1).

The predetermined value of the capacity setting means (25) and the predetermined value of the time ending means (23) may be the same value or different values.

Further, both the capacity setting means (25) and the time ending means (23) may be provided.

Further, the present invention is not limited to the refrigerant circulation circuit (1) of the embodiment, and is not limited to the refrigerant circuit (1) provided in the refrigeration container.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a refrigerant circuit diagram.

FIG. 3 is a characteristic diagram of the internal temperature with respect to time.

FIG. 4 is a control flowchart of a defrost operation.

FIG. 5 is a control flowchart of a defrost operation in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigerant circulation circuit 2 Controller 11 Compressor 12 Condenser 14 Evaporator 21 Operation detecting means 22 Operating time calculating means 23 Time ending means 24 Temperature ending means 25 Capacity setting means EV Electric expansion valve Th1 Suction pipe temperature sensor

Claims (3)

(57) [Claims] 1. A compressor (11), a condenser (12),
In a refrigerating apparatus provided with a refrigerant circuit (1) in which an expansion mechanism (EV) and an evaporator (14) are sequentially connected, an operation detecting means (2) for detecting the operation of the compressor (11).
1) and receiving the operation signal of the compressor (11) output from the operation detection means (21), accumulating the operation time of the compressor (11) from after the previous defrost operation to before the current defrost operation. At the same time, the operation time of the compressor (11) is calculated by calculating the ratio of the operation time at the time of pull-down after the defrost operation to the integrated time to be greater than the ratio of the operation time at the time of in-range after the pull-down operation. Receiving the calculation signal output by the calculating means (22) and the operating time calculating means (22) , and setting the calculated operating time in advance when the calculated operating time exceeds a predetermined value.
Until the maximum defrost operation time
If the defrosting operation is continued for two times, the defrosting operation is performed.
On the other hand, when the calculated operation time is equal to or less than a predetermined value, a time ending means (23) for ending the current defrost operation after a predetermined time shorter than the maximum time elapses in advance is provided. An operation control device for a refrigeration system. 2. The operation control device for a refrigeration system according to claim 1, wherein said suction gas temperature detection means (Th5) for detecting a suction gas temperature of said compressor (11), and said suction gas temperature detection means (Th5). Operating the refrigerating apparatus, comprising: temperature ending means (24) for terminating the defrost operation when the temperature of the intake gas during the defrost operation reaches a predetermined temperature in response to the output temperature signal. Control device. 3. A refrigerant circulation circuit (1) comprising a compressor (11) having a variable capacity, a condenser (12), an expansion mechanism (EV), and an evaporator (14) connected in order. In the refrigeration apparatus, an operation detecting means (2) for detecting the operation of the compressor (11).
1) and receiving the operation signal of the compressor (11) output from the operation detection means (21), accumulating the operation time of the compressor (11) from after the previous defrost operation to before the current defrost operation. At the same time, the operation time of the compressor (11) is calculated by calculating the ratio of the operation time at the time of pull-down after the defrost operation to the integrated time to be greater than the ratio of the operation time at the time of in-range after the pull-down operation. Receiving the calculation signal output from the operating time calculating means (22), and when the calculated operating time is greater than a predetermined value, the compressor capacity during defrost operation is reduced to a low capacity, and the compressor capacity is equal to or less than the predetermined value. And a capacity setting means (25) for setting the compressor capacity during defrost operation to a high capacity in the case of (1).