JPH10148404A - Controller for refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the compressor inlet superheat and the intermediate pressure by a method wherein a value which is output by a differential temperature detecting means, and a temperature set value are compared, and a control signal is output, and based on a result of the output, the throttle opening degree of a variable throttle device is controlled at every specified cycle. SOLUTION: A differential temperature between a value which is detected by a compressor inlet temperature detector 28 by a program of a refrigerating device, which is stored in an LSI 27, and a value which is detected by an evaporator temperature detector 29, is calculated, and the calculated value and a temperature set value are compared. Based on a result of the comparison, when the differential temperature is larger than the temperature set value, a control signal is output so that the throttle opening degree of a variable throttle device 13 may become smaller. Also, when the differential temperature is smaller than the temperature set value, the control signal is output so that the throttle opening degree of the variable throttle device 13 may become larger. By this method, a superheat of a compressor inlet refrigerant can be optimally kept.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to operation control of a refrigeration system and the like.

[0002]

2. Description of the Related Art A conventional technique of this kind is disclosed in
There is one described in JP-A-6-64256. This will be described below with reference to the drawings.

As shown in FIG. 17, the air conditioner passes through a compressor 1, a condenser 2, a first decompressor 3, a gas-liquid separator 4, a second decompressor 5, and an evaporator 6 to the compressor 1. The returning cycle is a basic cycle, and the gas separated by the gas-liquid separator 4 is passed through the gas pipe 7 and is injected into the compressor 1 from the injection pipe 8. In such an air conditioner, a flow rate control valve 9 is provided in a gas pipe 7, and the flow control valve 9 is provided on an outlet side of the evaporator 6.
Is controlled according to the refrigerant temperature. That is, when the refrigerant temperature decreases, the opening of the flow control valve 9 is reduced, and when the refrigerant temperature increases, the opening is increased. Also,
As shown in FIG. 18, in the case of a refrigeration cycle using ideal gas injection, the injection pressure Pinj that maximizes the coefficient of performance is Pd for the discharge pressure and Ps for the suction pressure.

[0004]

(Equation 1)

[0005]

[0006]

However, when the capacity is controlled by controlling the injection flow rate as described above, a refrigeration cycle as shown in FIG. 19 occurs, a pressure loss occurs in the flow rate control valve, and the compressor suction It is difficult to secure an optimal injection pressure according to the load while keeping the superheat constant. As a result, there was a problem that the compressor efficiency was reduced and the coefficient of performance was poor.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the coefficient of performance of a refrigeration system by optimizing the compressor suction superheat and the intermediate pressure without performing injection flow rate control.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a control device for a refrigeration system according to the present invention comprises a variable displacement compressor, a condenser, a variable throttle device, a gas-liquid separator, and a fixed throttle. A device that circularly connects the device and an evaporator, a circuit is provided for returning to the compressor after being vaporized by the gas-liquid separator, suction temperature detecting means for detecting a compressor suction temperature, and an evaporator for detecting an evaporator temperature Temperature detecting means, differential temperature calculating means for calculating a temperature difference between a value detected by the suction temperature detecting means and a value detected by the evaporator temperature detecting means, and a value outputted by the differential temperature detecting means First comparing means for comparing the pressure and the temperature set value and outputting a control signal; and a throttle device opening control means for controlling the throttle opening of the variable throttle device at predetermined intervals based on the result of the comparing means. It is a thing.

Further, another control device of the refrigerating apparatus of the present invention includes a variable displacement compressor, a condenser, a first variable throttle device, a gas-liquid separator, a second variable throttle device, An evaporator is connected in a ring, a circuit is provided for returning to the compressor after being vaporized by the gas-liquid separator, and the operating frequency detecting means for detecting the operating frequency of the compressor and the operating frequency detecting means for the compressor are detected. The first set intermediate pressure calculating means for calculating a target intermediate pressure from the calculated value, a suction temperature detecting means for detecting a compressor suction temperature, an evaporator temperature detecting means for detecting an evaporator temperature, A first throttle device opening control device for controlling a throttle opening of the first variable throttle device based on a calculation result obtained by the set intermediate pressure calculating device; and a suction temperature detection device. Value and the evaporator temperature detecting means. A difference temperature calculating means for calculating a temperature difference between the set value and a difference value, a comparing means for comparing a value output by the difference temperature detecting means with a temperature set value, and outputting a control signal, based on a result of the comparing means. A throttle device opening control means for controlling the throttle opening of the second variable throttle device at predetermined intervals.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has the following functions by the above means.

That is, a temperature difference calculating means for calculating a temperature difference between the value detected by the compressor suction temperature detecting means and the value detected by the evaporator temperature detecting means, and the temperature difference outputted by the temperature difference detecting means. By providing the first comparison means for comparing the value with the temperature set value and outputting a control signal, when the temperature difference is larger than the set value, control is performed such that the aperture of the variable aperture device is reduced. A signal is output, the opening degree of the expansion device is reduced, and when the temperature difference is smaller than the set value, a control signal is output so as to increase the opening amount of the variable device. As a result, the superheat of the refrigerant drawn into the compressor can be kept optimal.

Further, the temperature range in which the discharge refrigerant temperature can be taken is divided into a plurality of temperature zones, and the opening degree of the variable throttle device is determined and stored for each temperature zone with respect to the value that the operating frequency can take. By having the throttle opening degree storage means for controlling the opening degree of the variable throttle device, it is possible to keep the superheat of the refrigerant drawn into the compressor at an optimum level.

[0013] Further, by providing a set intermediate pressure calculating means for calculating a target intermediate pressure from a value detected by the compressor operating frequency detecting means, the throttle opening of the variable throttle device is controlled to control the intermediate pressure. Can be maintained at the set intermediate pressure.

The refrigerant temperature detecting means in the gas-liquid separator, the refrigerant pressure calculating means, the intermediate pressure calculating means, and the value calculated by the intermediate pressure calculating means are compared with the set intermediate pressure calculating means. With such a comparison means, the opening degree of the variable throttle device can be controlled to maintain the intermediate pressure at the set intermediate pressure.

The condenser temperature detecting means, the evaporator temperature detecting means, the refrigerant pressure calculating means, and a comparing means for comparing a value calculated by the intermediate pressure calculating means with the set intermediate pressure calculating means. In this case, the opening degree of the variable throttle device can be controlled to maintain the intermediate pressure at the set intermediate pressure.

[0016] In addition, by providing a set intermediate pressure calculating means for calculating a target intermediate pressure from a value detected by the compressor operating frequency detecting means, the throttle opening of the first variable throttle device is controlled. Means for maintaining the intermediate pressure at the set intermediate pressure, and calculating a temperature difference between a value detected by the compressor suction temperature detecting means and a value detected by the evaporator temperature detecting means. And a comparing means for comparing a value output by the temperature difference detection means with a temperature set value and outputting a control signal, so that when the temperature difference is larger than the set value, the second variable throttle device A control signal is output so that the opening degree of the throttle becomes small, and the opening degree of the second expansion device becomes small. When the temperature difference is smaller than the set value, the opening degree of the second variable device becomes large. Control signal There is output, the opening is increased in the second throttle device, it is possible to maintain the superheat of the compressor suction refrigerant optimally.

Further, the refrigerant temperature detecting means in the gas-liquid separator, the refrigerant pressure calculating means, the intermediate pressure calculating means, and the value calculated by the intermediate pressure calculating means and the set intermediate pressure calculating means are compared. With the comparison means, the intermediate pressure can be maintained at the set intermediate pressure by controlling the opening degree of the first variable throttle device.

Further, the condenser temperature detecting means, the evaporator temperature detecting means, the refrigerant pressure calculating means, and a comparing means for comparing the value calculated by the intermediate pressure calculating means with the set intermediate pressure calculating means. By controlling the opening degree of the first variable throttle device, the intermediate pressure can be maintained at the set intermediate pressure.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
Will be described with reference to FIG.

FIG. 1 is a refrigeration cycle diagram according to a first embodiment of the present invention. In the figure, 11 is a compressor, 1
2 is a condenser, 13 is a variable throttle device, 14 is a gas-liquid separator,
Reference numeral 15 denotes a fixed throttle device, and 16 denotes an evaporator, which are sequentially connected in a ring shape, and are provided with a circuit that is vaporized by the gas-liquid separator 14 and then returned to the compressor 11. 17 is LS
I and 18 are suction temperature detectors for detecting the compressor suction temperature, and 19 is an evaporator temperature detector for detecting the evaporator temperature.

In the above configuration, the configuration and operation of the control circuit during operation of the refrigeration system will be described with reference to FIG. Figure 2 shows the LS
5 is a flowchart showing a program of the refrigerating apparatus stored in I. As can be seen from this flowchart, in the present invention, the aperture of the variable aperture device 15 is controlled so as to keep the intake superheat optimal.

When an operation instruction is given by a remote controller or forced operation, the operation of the refrigeration apparatus starts. At the same time, step 50 of FIG. 2 is executed.
T1 <is calculated by comparing the difference h between the suction temperature Tsuc detected by the suction temperature detector and the evaporator temperature Teva detected by the evaporator temperature detector with the set values T1 and T2.
If h <T2, a "YES" determination is made and the process returns to step 50. If T1 ≧ h and T2 ≦ h, “NO”
Is determined, and the process proceeds to step 51. Step 51
Then, by the comparing means of the difference temperature h and the set value T1, T1 ≧
If h, a determination of "YES" is made, and the routine proceeds to step 52. In step 52, the throttle opening M of the variable throttle device is
A control signal for setting ₁ to M ₁ + N is output, and the process returns to step 50. If T1 <h, a "NO" determination is made and the process proceeds to step 53. In step 53, a control signal for setting the aperture M ₁ of the variable aperture device to M ₁ −N is output, and the process returns to step 50.

The intention of each step will be described. That is, step 50 is a comparison operation for judging whether or not the compressor superheat is optimal based on the difference between the suction temperature and the evaporator temperature, and step 51 is for judging whether the superheat is too small. A comparison operation,
In step 52, the aperture of the variable aperture device is increased, and the process returns to step 50. In step 53, the aperture of the variable aperture device is reduced, and the process returns to step 50.

As described above, by configuring the injection cycle while keeping the compressor superheat optimal, the refrigeration system can be operated with a high coefficient of performance.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a refrigeration cycle diagram in the second embodiment of the present invention. The difference from the first embodiment is that an operating frequency detector 20 for detecting the compressor operating frequency and a discharge temperature detector 21 for detecting the discharge temperature are provided.

The configuration and operation of the control circuit during the operation of the refrigeration system will be described with reference to FIG. FIG. 4 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the suction superheat is predicted from the discharge temperature and the operating frequency, and the variable throttle device 1 is adjusted so that the superheat is optimal.
5 is controlled.

When an operation instruction is given by a remote controller or a forced operation, the operation of the refrigeration apparatus starts. At the same time, step 54 in FIG. 4 is executed.
The operation frequency is detected by the operation frequency detector, and the discharge temperature is detected by the discharge temperature detector. In step 55, the throttle opening of the variable throttle device is calculated from the operating frequency and the discharge temperature, and the process proceeds to step 56. In step 56, the variable throttle device is controlled so that the variable throttle opening M _m1 calculated in step 55 is obtained, and the process returns to step 54.

The intention of each step will be described. That is, step 54 is a detecting means for detecting the compressor operating frequency and the discharge temperature, step 55 is a calculating means for calculating an optimum variable throttle device opening, and step 56 is controlling the throttle opening of the variable throttle device. And step 50
Return to

As described above, even if the operating frequency changes, the refrigeration system can be operated with a high coefficient of performance by continuously configuring the injection cycle while maintaining the compressor superheat at an optimum level.

Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a refrigeration cycle diagram in the third embodiment of the present invention. The difference from the first embodiment is that an operating frequency detector 20 for detecting the compressor operating frequency is provided.

The configuration and operation of the control circuit during operation of the refrigeration system will be described with reference to FIG. FIG. 6 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the optimum intermediate pressure is calculated from the operating frequency, and the throttle opening of the variable throttle device 15 is controlled so that the intermediate pressure is optimum.

When an operation instruction is given by a remote controller or a forced operation, the operation of the refrigeration apparatus starts. At the same time, step 57 in FIG. 6 is executed.
The operation frequency is detected by the operation frequency detector, and the process proceeds to step 58. In step 58, to calculate the set intermediate pressure P ₁ from the operating frequency, the process proceeds to step 59. In step 59, the set intermediate pressure P _1, to calculate the variable throttle device opening M _{m @ 2,} the process proceeds to step 60. Step 6
If it is 0, the variable throttle device is controlled so that the variable throttle opening _Mm2 calculated in step 59 is obtained, and the process returns to step 57.

The purpose of each step will be described. That is, step 57 is a detecting means for detecting a compressor operating frequency, step 58 is a calculating means for calculating a set intermediate pressure, step 59 is a calculating means for calculating an optimum variable throttle device opening, 60 controls the aperture of the variable aperture device and returns to step 57.

As described above, even if the operating frequency changes, the injection cycle is configured while continuously maintaining the intermediate pressure at the optimum value, so that the refrigeration system can be operated at a high coefficient of performance without controlling the injection flow rate. Becomes possible.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a refrigeration cycle diagram in the fourth embodiment of the present invention. The difference from the first embodiment is that a condenser temperature detector 22 for detecting the condenser temperature and a gas-liquid separator temperature detector 23 for detecting the temperature of the gas-liquid separator are provided. is there.

The configuration and operation of the control circuit during the operation of the refrigeration system will be described with reference to FIG. FIG. 8 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the set intermediate pressure is calculated from the condenser temperature and the evaporator temperature,
The actual intermediate pressure is calculated from the gas-liquid separator temperature, the set intermediate pressure is compared with the intermediate pressure, and the throttle opening of the variable throttle device 15 is controlled so that the intermediate pressure is optimal.

Operation by remote control or forced operation
Is issued, the operation of the refrigeration apparatus starts. At the same time
Step 61 in FIG. 8 is executed at step 61.
Condenser temperature by condenser temperature detector and evaporator temperature detector
The temperature and the evaporator temperature are detected, and the process proceeds to step 62. S
At step 62, the temperature is being set based on the condenser temperature and the evaporator temperature.
Pressure P_TwoThen, the process proceeds to step 63. Step
In step 63, the gas-liquid separator temperature is detected by the gas-liquid separator temperature detector.
The degree is detected, and the process proceeds to step 64. In step 64
From the gas-liquid separator temperature to the intermediate pressure P_m1To estimate
Proceed to step 65. In step 65, the setting range of the intermediate pressure is set.
By the comparison operation in the box, P_Two-N₁<P _m1<P_Two+ N₁
If (N₁: For example, 100 kpa) "YES" judgment
Then, the process returns to step 61. P_Two-N₁≧ P_m1And
P_Two+ N₁≤P_m1If so, a "NO" determination is made and the
Proceed to Step 66. In step 66, P₁-N₁And P
_m1By means of comparison with₁-N₁> P_m1Then "YE
Is determined, and the process proceeds to step 67. Steps
At 67, the throttle opening M of the variable throttle device is_FourTo M_Four+ N
The control signal is output, and the process returns to step 65. P₁-N₁≤
P_m1If so, a "NO" determination is made and
Proceed. In step 68, the throttle opening M of the variable throttle device
_FourTo M_FourA control signal of −N is output.
Return.

The intention of each step will be described. That is, step 61 is a detecting means for detecting the condenser temperature and the evaporator temperature, step 62 is a calculating means for calculating the set intermediate pressure, and step 63 is a detecting means for detecting the temperature of the gas-liquid separator. Step 64 is a calculating means for calculating the intermediate pressure P _m1 , and step 65 is a comparison operation for determining whether or not the actual intermediate pressure value falls within the pressure range of the set intermediate pressure.
Is a comparison operation for determining whether or not the intermediate pressure is lower than the lowest value of the set intermediate pressure. Step 67 increases the aperture of the variable throttle device and returns to step 65. And the process returns to step 65.

As described above, by controlling the throttle opening of the variable throttle device so as to more accurately maintain the set intermediate pressure, the refrigeration system can be operated with a high coefficient of performance.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a refrigeration cycle diagram in the fifth embodiment of the present invention. The difference from the first embodiment is that a condenser temperature detector 22 for detecting the condenser temperature and a gas-liquid separator pressure detector 24 for detecting the pressure in the gas-liquid separator are provided. It is.

The configuration and operation of the control circuit during the operation of the refrigeration system will be described with reference to FIG. FIG. 9 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the set intermediate pressure is calculated from the condenser temperature and the evaporator temperature,
The set intermediate pressure is compared with the gas-liquid separator pressure, that is, the intermediate pressure, and the throttle opening of the variable throttle device 15 is controlled so that the intermediate pressure is optimized.

Operate by remote control or forced operation
Is issued, the operation of the refrigeration apparatus starts. At the same time
In step 70 of FIG.
Is condensed by the condenser temperature detector and the evaporator temperature detector
Detector temperature and evaporator temperature, and proceed to step 71
No. In step 71, from the condenser temperature and the evaporator temperature,
Set intermediate pressure P_ThreeThen, the process proceeds to step 72.
In step 72, the gas-liquid separator is detected by the gas-liquid separator pressure detector.
Release pressure P_m2Is detected, and the process proceeds to step 73. Step
In step 73, the comparison operation is performed in the set range of the intermediate pressure.
, P_Three-N₁<P_m2<P_Three+ N₁If yes then
Then, the process returns to step 70. P_Three-N₁≧ P_m2And
P_Three+ N₁≤P_m2If so, a "NO" determination is made and the
Proceed to step 74. In step 74, P_Two-N₁And P
_m2By means of comparison with_Two-N₁> P _m2Then "YE
Is determined, and the process proceeds to step 73. Steps
At 73, the throttle opening M of the variable throttle device_FiveTo M_Five+ N
The control signal is output, and the process returns to step 73. P_Two-N₁When
≤P_m2If so, a "NO" determination is made and step 76
Proceed to In step 76, the throttle opening of the variable throttle device is
M_FiveTo M_FiveA control signal of −N is output, and
Return to

The intention of each step will be described. That is, step 70 is a detecting means for detecting the condenser temperature and the evaporator temperature, step 71 is a calculating means for calculating the set intermediate pressure, and step 72 is a detecting means for detecting the pressure of the gas-liquid separator. Step 73 is a comparison operation for determining whether or not the actual intermediate pressure value falls within the pressure range of the set intermediate pressure. Step 74 is to determine whether the intermediate pressure is lower than the lowest value of the set intermediate pressure. In step 75, the aperture of the variable aperture device is increased and the process returns to step 73. In step 76, the aperture of the variable aperture device is reduced and the process returns to step 73.

As described above, by detecting the refrigerant pressure in the gas-liquid separator, the throttle opening of the variable throttle device is controlled accurately and promptly so as to maintain the set intermediate pressure.
The refrigeration system can be operated with a high coefficient of performance.

Next, a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a refrigeration cycle diagram in the sixth embodiment of the present invention. First
The difference from the third embodiment is that a first throttle device 25 is provided on the upstream side of the gas-liquid separator, a second throttle device 26 and the operating frequency detector 20 are provided on the downstream side.

The configuration and operation of the control circuit during the operation of the refrigeration system will be described with reference to FIG. FIG. 12 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the optimum intermediate pressure is calculated from the operation frequency, and while controlling the throttle opening of the first throttle device 25 so that the intermediate pressure is optimum, the suction superheat is reduced. The second aperture device 26 is controlled so as to maintain the optimum value.

When an operation instruction is given by a remote controller or forced operation, the operation of the refrigeration apparatus starts. At the same time, step 77 in FIG. 12 is executed. In step 77, the operating frequency is detected by the operating frequency detector, and the process proceeds to step 78. In step 78, to calculate the set intermediate pressure P ₄ from the operating frequency, the process proceeds to step 79.
In step 79, the set intermediate pressure P _4, and calculates a first throttle device opening M _m3, the process proceeds to step 80. In step 80, the throttle opening M _m3 calculated in step 79
The first diaphragm device is controlled so that In step 81, the difference temperature h between the suction temperature Tsuc detected by the suction temperature detector and the evaporator temperature Teva detected by the evaporator temperature detector, and the set values T1 and T
If T1 <h <T2 as a result of comparison with
S "is determined, and the process returns to step 77. If T1 ≧ h and T2 ≦ h, a “NO” determination is made and the process proceeds to step. In step 82, the difference temperature h and the set value T
If T1 ≧ h, a determination of “YES” is made by the comparing means with 1, and the process proceeds to step 83. In step 83, control signals the opening M ₇ aperture of the second throttle device and M ₇ + N is output, the flow returns to step 77. If T1 <h, a "NO" determination is made and the process proceeds to step 84. In step 84, the opening M ₇ aperture of the second throttle device M ₇ -
A control signal for N is output, and the process returns to step 77.

The purpose of each step will be described. That is, step 77 is a detecting means for detecting the compressor operating frequency, step 78 is a calculating means for calculating the set intermediate pressure, step 79 is a calculating means for calculating the optimal variable throttle device opening, 80 is the first
The throttle opening of the throttle device is controlled, and the process proceeds to step 81. Step 81 is a comparison operation for judging whether or not the compressor superheat is optimal based on the difference between the suction temperature and the evaporator temperature. Step 82 is a comparison operation for judging whether the superheat is too small. And step 8
Step 3 is to increase the throttle opening of the second throttle device and to execute Step 7
Returning to step 7, in step 84, the aperture of the second aperture device is reduced, and the process returns to step 77.

As described above, while controlling the opening degree of the first expansion device so as to keep the intermediate pressure at an optimum value, the opening degree of the second expansion device is controlled so as to keep the superheat of the refrigerant drawn into the compressor at an optimum level. By doing so, it becomes possible to operate the refrigeration apparatus with a higher coefficient of performance.

Next, a seventh embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a refrigeration cycle diagram in the seventh embodiment of the present invention. Sixth
The difference from this embodiment is that a condenser temperature detector 22 for detecting the condenser temperature and a gas-liquid separator temperature detector 23 for detecting the temperature of the gas-liquid separator are provided.

The configuration and operation of the control circuit during the operation of the refrigeration system will be described with reference to FIG. FIG. 14 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the set intermediate pressure is calculated from the condenser temperature and the evaporator temperature, the actual intermediate pressure is calculated from the gas-liquid separator temperature, and the set intermediate pressure and the intermediate pressure are compared. While controlling the degree of opening of the first expansion device 25 so that the intermediate pressure is optimal, the second expansion device 2 is designed to optimize the suction superheat.
6 is controlled.

Operation by remote control or forced operation
Is issued, the operation of the refrigeration apparatus starts. At the same time
Step 85 of FIG. 14 is executed.
Is condensed by the condenser temperature detector and the evaporator temperature detector
Detector temperature and evaporator temperature, proceed to step 86
No. In step 86, the temperature of the condenser and the temperature of the evaporator are calculated.
Set intermediate pressure P_FiveThen, the process proceeds to step 87.
In step 87, the gas-liquid separator is detected by the gas-liquid separator temperature detector.
The separator temperature is detected, and the process proceeds to step 88. Step 8
8, the intermediate pressure P is calculated from the gas-liquid separator temperature._m3To estimate
Proceed to Step 89. In step 89, the intermediate pressure is set.
By the comparison operation in the fixed range, P_Five-N₁<P_m3<P_Five
+ N₁If so, a determination of "YES" is made and step 9
Proceed to 3. P _Five-N₁≧ P_m3And P_Five+ N₁≤P_m3That
If “NO” is determined, the process proceeds to step 90. S
In Step 90, P_Five-N₁And P_m3By means of comparison with
P_Five-N₁> P_m3If so, a determination of "YES" is made and the
Proceed to Step 91. In step 91, the first aperture device
Throttle opening M₈To M₈+ N is output as a control signal,
Return to step 89. P_Five-N₁≤P_m3Then "NO"
Is determined, and the process proceeds to step 92. Step 92
Then, the throttle opening M of the first throttle device₈To M₈-N
A control signal is output, and the process returns to step 89. Step 93
Then, the suction temperature Tsu detected by the suction temperature detector
c and the evaporator temperature Te detected by the evaporator temperature detector
By comparing the differential temperature h of va with the set values T1 and T2,
If T1 <H <T2, a “YES” determination is made and the
Return to step 85. If T1 ≧ h and T2 ≦ h,
A "NO" determination is made, and the process proceeds to step 94. Stay
In step 94, a comparison means for comparing the temperature difference h with the set value T1 is used.
If T1 ≧ h, a “YES” determination is made and
Proceed to step 95. In step 95, the second diaphragm device
Throttle opening M₉To M₉+ N is output, and the
Return to step 93. If T1 <h, no determination is made
Then, the process proceeds to step 96. In step 96, the second
Throttle opening M of the throttle device₉To M₉-N
The process returns to step 93.

The intention of each step will be described. That is, step 85 is a detecting means for detecting the condenser temperature and the evaporator temperature, step 86 is a calculating means for calculating the set intermediate pressure, and step 87 is a detecting means for detecting the temperature of the gas-liquid separator. Step 88 is a calculating means for calculating the intermediate pressure P _m3 , and Step 89 is a comparison operation for determining whether or not the actual intermediate pressure value falls within the pressure range of the set intermediate pressure.
Is a comparison operation for determining whether or not the intermediate pressure is lower than the lowest value of the set intermediate pressure. Step 91 increases the throttle opening of the first throttle device and returns to Step 89. The throttle opening of the first throttle device is reduced, and the process returns to step 89. Step 93 is a comparison operation for judging whether or not the compressor superheat is optimal from the difference between the suction temperature and the evaporator temperature. Step 94 is a comparison operation for judging whether the superheat is too small. In step 95, the aperture of the second aperture device is increased and the process returns to step 93. In step 96, the aperture of the second aperture device is decreased and the process returns to step 93.

As described above, the optimum intermediate pressure is calculated by detecting the condenser temperature and the evaporator temperature, and is compared with the predicted intermediate pressure to control the throttle opening of the first throttle device. By controlling the second expansion device so as to keep the intake superheat optimal, the refrigeration system can be more accurately operated with a high coefficient of performance.

Next, an eighth embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a refrigeration cycle diagram in the eighth embodiment of the present invention. Sixth
The difference from the embodiment is that a condenser temperature detector 22 for detecting the condenser temperature and a gas-liquid separator refrigerant pressure detector 24 for detecting the refrigerant pressure of the gas-liquid separator are provided. is there.

The configuration and operation of the control circuit during the operation of the refrigeration system will be described with reference to FIG. FIG. 16 is a flowchart showing a program of the refrigeration apparatus stored in the LSI. As can be seen from this flowchart, in the present invention, the set intermediate pressure is calculated from the condenser temperature and the evaporator temperature, the set intermediate pressure is compared with the intermediate pressure, and the first expansion device 25 is adjusted so that the intermediate pressure becomes optimal. The second throttle device 26 is controlled so that the suction superheat is optimized while controlling the throttle opening of the second throttle device.

When an operation instruction is given by a remote controller or a forced operation, the operation of the refrigeration apparatus starts. At the same time, step 101 in FIG.
Then, the condenser temperature and the evaporator temperature are detected by the condenser temperature detector and the evaporator temperature detector, and the process proceeds to step 102. In step 102, it calculates the set intermediate pressure P ₆ from the condenser temperature and the evaporator temperature, the process proceeds to step 103. In Step 103, the gas-liquid separator pressure _Pm4 is detected by the gas-liquid separator pressure detector, and the process _proceeds to Step 104. In step 104, if P ₆ −N ₁ <P _m4 <P ₆ + N ₁ by the comparison operation in the intermediate pressure setting range, a determination of “YES” is made, and the process proceeds to step 108.
If P ₆ −N ₁ ≧ P _m4 and P ₆ + N ₁ ≦ P _m4 , “NO”
Is determined, and the process proceeds to step 105. Step 1
At 05, P ₆ −N ₁ is compared with P _m4 by P ₆ −
If N _1> P a _m4 determination of "YES" is made, the process proceeds to step 106. In step 106, control signals the opening M ₁₀ aperture of the first throttle device and M ₁₀ + N is output, the flow returns to step 104. If P ₆ −N ₁ ≦ P _m4 , a “NO” determination is made and the process proceeds to step 107. In step 107, the opening M ₁₀ aperture of the first throttle device M
A control signal of _10- N is output, and the process returns to step 104. In step 108, the difference temperature h between the suction temperature Tsuc detected by the suction temperature detector and the evaporator temperature Teva detected by the evaporator temperature detector and the set values T1 and T2.
"YES" if T1 <h <T2
Is determined, and the process returns to step 101. If T1 ≧ h and T2 ≦ h, a “NO” determination is made and the process proceeds to step 109. In step 109, if T1 ≧ h, “YES” is determined by comparing the difference temperature h with the set value T1.
Is determined, and the process proceeds to step 110. Step 1
In 10, a control signal the opening M ₁₁ aperture of the second throttle device and M ₁₁ + N is output, the flow returns to step 108. T1
If <h, the determination of “NO” is made and step 111
Proceed to In step 111, control signals the opening M ₁₁ aperture of the second throttle device and M ₁₁ -N is output, the flow returns to step 108.

The intention of each step will be described. That is, step 101 is a detecting means for detecting the condenser temperature and the evaporator temperature, step 102 is a calculating means for calculating the set intermediate pressure, and step 103 is a detecting means for detecting the pressure P _m4 of the gas-liquid separator. Step 104 is a comparison operation for determining whether or not the actual intermediate pressure value falls within the pressure range of the set intermediate pressure. Step 105 is whether or not the intermediate pressure is lower than the lowest value of the set intermediate pressure. Is a comparison operation for determining whether
In step 06, the aperture of the first aperture device is increased and the process returns to step 104. In step 107, the aperture of the first aperture device is decreased and the process returns to step 104. Step 1
08 is a comparison operation for judging whether or not the compressor superheat is optimal from the difference between the suction temperature and the evaporator temperature, and a step 109 is a comparison operation for judging whether the superheat is too small. And step 110
Then, the throttle opening of the second throttle device is increased, and step 1 is performed.
Returning to 08, in step 111, the aperture of the second aperture device is reduced, and the process returns to step 108.

As described above, the optimum intermediate pressure is calculated by detecting the condenser temperature and the evaporator temperature, and is compared with the actual intermediate pressure to control the throttle opening of the first throttle device while controlling the suction opening. By controlling the second expansion device so as to maintain the superheat optimally, it is possible to more accurately and quickly operate the refrigeration system with a high coefficient of performance.

[0060]

The present invention has the following effects by the above means.

That is, a temperature difference calculating means for calculating a temperature difference between the value detected by the compressor suction temperature detecting means and the value detected by the evaporator temperature detecting means, and the temperature difference outputted by the temperature difference detecting means. With the comparison means that compares the value with the temperature set value and outputs a control signal, it is possible to control the opening degree of the variable throttle device so as to keep the superheat of the refrigerant sucked into the compressor at an optimum level. The operation of the refrigeration system at the coefficient becomes possible.

Further, the temperature range in which the discharge temperature can be taken is divided into a plurality of temperature zones, and the throttle opening of the variable throttle device is determined and stored for each value of the operating frequency in each temperature zone. By having the opening storage means,
The throttle opening of the variable throttle device can be controlled so as to optimally maintain the superheat of the refrigerant drawn into the compressor, and the refrigeration device can be continuously operated with a high coefficient of performance.

Further, by providing a set intermediate pressure calculating means for calculating a target intermediate pressure from a value detected by the compressor operating frequency detecting means, the throttle opening of the variable throttle device is maintained so as to maintain the set intermediate pressure. The refrigeration system can be operated with a high coefficient of performance without controlling the injection flow rate.

Further, the refrigerant temperature detecting means in the gas-liquid separator, the refrigerant pressure calculating means, the intermediate pressure calculating means, and the value calculated by the intermediate pressure calculating means are compared with the set intermediate pressure calculating means. With the comparison means, the throttle opening of the variable throttle device can be controlled so as to more accurately maintain the set intermediate pressure, and the refrigeration system can be operated with a high coefficient of performance.

The condenser temperature detecting means, the evaporator temperature detecting means, the refrigerant pressure calculating means, and the comparing means for comparing the value calculated by the intermediate pressure calculating means with the set intermediate pressure calculating means. , It is possible to more accurately and quickly control the throttle opening of the variable throttle device so as to maintain the set intermediate pressure.

The first variable throttle device includes a set intermediate pressure calculating means for calculating a target intermediate pressure from a value detected by the compressor operating frequency detecting means so as to maintain the set intermediate pressure. Temperature difference calculating means for calculating the temperature difference between the value detected by the compressor suction temperature detecting means and the value detected by the evaporator temperature detecting means while controlling the throttle opening degree of the throttle valve, and the differential temperature detecting means The control means outputs a control signal by comparing the value output by the control unit and the temperature setting value, thereby controlling the opening degree of the second variable throttle device so as to optimally maintain the superheat of the refrigerant drawn into the compressor. It is possible to operate the refrigeration apparatus with a higher coefficient of performance.

Also, the refrigerant temperature detecting means in the gas-liquid separator, the refrigerant pressure calculating means, the intermediate pressure calculating means, and the value calculated by the intermediate pressure calculating means and the set intermediate pressure calculating means are compared. By having the comparing means, it is possible to control the throttle opening of the first variable throttle device so as to maintain the set intermediate pressure, and to maintain the suction superheat optimally and more accurately with a high coefficient of performance. The operation of the refrigeration system becomes possible.

Also, a comparison means for comparing the value calculated by the condenser temperature detection means, the evaporator temperature detection means, the refrigerant pressure calculation means, and the intermediate pressure calculation means with the set intermediate pressure calculation means. By having the above, it is possible to control the throttle opening of the first variable throttle device so as to maintain the set intermediate pressure, and more accurately and promptly with a high coefficient of performance while maintaining the optimal suction superheat. The operation of the refrigeration system becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle in a first embodiment of a control device for a refrigeration apparatus of the present invention.

FIG. 2 is a flowchart in the embodiment.

FIG. 3 is a refrigeration cycle configuration diagram in a second embodiment of the control device of the refrigeration apparatus of the present invention.

FIG. 4 is a flowchart in the embodiment.

FIG. 5 is a configuration diagram of a refrigeration cycle in a third embodiment of the control device of the refrigeration apparatus of the present invention.

FIG. 6 is a flowchart in the embodiment.

FIG. 7 is a configuration diagram of a refrigeration cycle in a fourth embodiment of the control device of the refrigeration apparatus of the present invention.

FIG. 8 is a flowchart in the embodiment.

FIG. 9 is a configuration diagram of a refrigeration cycle in a fifth embodiment of the control device of the refrigeration apparatus of the present invention.

FIG. 10 is a flowchart in the embodiment.

FIG. 11 is a configuration diagram of a refrigeration cycle in a sixth embodiment of the control device of the refrigeration apparatus of the present invention.

FIG. 12 is a flowchart in the embodiment.

FIG. 13 is a configuration diagram of a refrigeration cycle in a seventh embodiment of the control device for a refrigeration apparatus of the present invention.

FIG. 14 is a flowchart in the embodiment.

FIG. 15 is a configuration diagram of a refrigeration cycle in an eighth embodiment of the control device for a refrigeration apparatus of the present invention.

FIG. 16 is a flowchart in the embodiment.

FIG. 17 is a configuration diagram of a refrigeration cycle in a conventional refrigeration apparatus.

FIG. 18 is a conventional ideal gas injection refrigeration cycle Mollier diagram.

FIG. 19 is a refrigeration cycle Mollier diagram in a conventional refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 First decompressor 4 Gas-liquid separator 5 Second decompressor 6 Evaporator 7 Gas pipe 8 Injection pipe 9 Flow control valve 10 Temperature sensing cylinder 11 Variable capacity compressor 12 Condenser 13 Variable Restrictor 14 Gas-liquid separator 15 Fixed restrictor 16 Evaporator 17 Injection pipe 20 Operating frequency detector 21 Discharge temperature detector 22 Condenser temperature detector 23 Refrigerant temperature detector in gas-liquid separator 24 Refrigerant in gas-liquid separator Pressure detector 25 First throttle device 26 Second throttle device 27 LSI 28 Compressor suction temperature detector 29 Evaporator temperature detector

Continued on the front page (72) Inventor: Adult Yamaguchi, Kadoma, Osaka 1006, Kadoma, Matsushita Electric Industrial Co., Ltd. Person Shigeru Nari 1006 Kazuma, Kazuma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Koji Murozono 1006 Kazuma, Kazuma, Kazuma, Osaka Pref. 1006 Ojimon Kadoma Matsushita Electric Industrial Co., Ltd. (72) Inventor Masaki Yamamukai 1006 Ojimon Kadoma, Kadoma City, Osaka Pref.Matsushita Electric Industrial Co., Ltd. Inside the corporation

Claims (8)

[Claims] 1. A variable displacement compressor, a condenser, a variable throttle device, a gas-liquid separator, a fixed throttle device, and an evaporator are connected in a ring shape, and after being vaporized by the gas-liquid separator. A circuit for returning a refrigerant to the compressor; a suction temperature detecting means for detecting a suction refrigerant temperature of the compressor; an evaporator temperature detecting means for detecting a refrigerant temperature of the evaporator; and a detection by the suction temperature detecting means. A difference temperature calculating means for calculating a difference between the detected value and a value detected by the evaporator temperature detecting means, and a control signal is output by comparing the value output by the differential temperature detecting means with a temperature set value. A control device for a refrigeration system, comprising: a first comparing unit; and a throttle device opening control unit that controls a throttle opening of the variable throttle device at predetermined intervals based on an output result of the first comparing device. 2. A discharge refrigerant temperature detecting means for detecting a discharge temperature of the compressor, an operating frequency detecting means of the compressor, and a temperature range in which the discharge temperature can be taken is divided into a plurality of temperature zones. A throttle opening storage means for storing the throttle opening of the variable throttle device in correspondence with the value that the operating frequency of the machine can take for each of the temperature zones, and storing the discharge temperature detecting means and the operating frequency detecting means; 2. The throttle opening of the variable throttle device is calculated at predetermined intervals using data obtained from the throttle opening storage means, and the throttle opening of the variable throttle device is controlled based on the calculation result. Refrigeration equipment control device. 3. A first set intermediate pressure calculation means for calculating a target intermediate pressure from a value detected by an operation frequency detection means of the compressor, wherein the first intermediate pressure calculation means obtains the calculated intermediate pressure. The control device for a refrigerating device according to claim 1, wherein a throttle opening of the variable throttle device is controlled based on a result. 4. A condenser temperature detecting means for detecting a temperature of the condenser, a gas-liquid separator refrigerant temperature detecting means for detecting a refrigerant temperature in the gas-liquid separator, and a refrigerant pressure for calculating a refrigerant pressure from the refrigerant temperature. Calculating means, and second set intermediate pressure calculating means for calculating a set intermediate pressure from the condenser pressure and the evaporator pressure, wherein the value detected by the condenser temperature detecting means and the value detected by the evaporator temperature detecting means are provided. From the value and the value detected by the gas-liquid separator temperature detecting means, the refrigerant pressure calculating means calculates the condenser pressure, the evaporator pressure, and the intermediate pressure of the refrigerant, and calculates the condenser pressure and the evaporator pressure. Calculating a set intermediate pressure by the second set intermediate pressure calculating means, and providing a second comparing means for comparing the intermediate pressure with the set intermediate pressure, based on a comparison result of the second comparing means. Variable aperture The control device for a refrigeration system according to claim 1, wherein the control device controls an opening degree of a throttle of the cooling device. 5. A condenser temperature detecting means, a gas-liquid separator pressure detecting means, a refrigerant pressure calculating means for calculating a refrigerant pressure from a refrigerant temperature, and a refrigerant pressure calculating means for calculating a set intermediate pressure from the condenser pressure and the evaporator pressure. 2, a set intermediate pressure calculating means is provided, and the condenser pressure and the evaporator pressure are calculated by the refrigerant pressure calculating means based on the value detected by the condenser temperature detecting means and the value detected by the evaporator temperature detecting means. And a third set intermediate pressure is calculated by the second set intermediate pressure calculating means from these values, and the set intermediate pressure is compared with the refrigerant pressure in the gas-liquid separator, that is, the intermediate pressure of the refrigerant. 2. A control device for a refrigerating apparatus according to claim 1, further comprising means for controlling a throttle opening of said variable throttle device based on a comparison result of said third comparing means. 6. A gas-liquid separator, comprising: a variable capacity compressor, a condenser, a first variable throttle device, a gas-liquid separator, a second variable throttle device, and an evaporator connected in a ring. A circuit for returning the refrigerant to the compressor after being vaporized by the compressor; an operating frequency detecting means for detecting an operating frequency of the compressor; and a target refrigerant based on a value detected by the compressor operating frequency detecting means. The first set intermediate pressure calculating means for calculating the intermediate pressure of the first pressure, the suction temperature detecting means for detecting the compressor suction refrigerant temperature, the evaporator temperature detecting means for detecting the temperature of the evaporator, A first throttle device opening control device for controlling the throttle opening of the first variable throttle device, based on a calculation result obtained by the set intermediate pressure calculating device, and detecting a refrigerant suction temperature of the compressor. The value detected by the suction temperature detecting means and the value Temperature difference calculating means for calculating a difference between the temperature detected by the evaporator temperature detecting means, and fourth comparing means for comparing the value output by the temperature difference detecting means with a temperature set value and outputting a control signal And a refrigeration system control device provided with a throttle device opening control device for controlling the throttle opening of the second variable throttle device at predetermined intervals based on a comparison result of the fourth comparing device. 7. A condenser temperature detecting means, a refrigerant temperature detecting means in the gas-liquid separator, a refrigerant pressure calculating means for calculating a refrigerant pressure from the refrigerant temperature, and a set intermediate pressure from the condenser pressure and the evaporator pressure. Providing a second set intermediate pressure calculating means,
From the value detected by the condenser temperature detecting means, the value detected by the evaporator temperature detecting means, and the value detected by the gas-liquid separator temperature detecting means, the condenser pressure and the refrigerant pressure calculating means are used. Calculating the evaporator pressure and the intermediate pressure of the refrigerant, calculating the set intermediate pressure from the condenser pressure and the evaporator pressure by the second set intermediate pressure calculating means, and comparing the intermediate pressure with the set intermediate pressure 7. The control device for a refrigerating apparatus according to claim 6, further comprising: a fifth comparing unit that controls the throttle opening of the first variable throttle device based on a comparison result of the fifth comparing unit. 8. A condenser temperature detecting means, a gas-liquid separator pressure detecting means, a refrigerant pressure calculating means for calculating a refrigerant pressure from a refrigerant temperature, and a setting for calculating a set intermediate pressure from the condenser pressure and the evaporator pressure. An intermediate pressure calculating means is provided, and the refrigerant pressure calculating means calculates the condenser pressure and the refrigerant pressure based on the value detected by the condenser temperature detecting means and the value detected by the evaporator temperature detecting means for detecting the temperature of the evaporator. The sixth step of calculating the evaporator pressure, calculating the set intermediate pressure from these values by the second set intermediate pressure calculating means, and comparing the gas-liquid separator pressure, that is, the intermediate pressure of the refrigerant, with the set intermediate pressure. 7. The control device for a refrigerating apparatus according to claim 6, further comprising: comparing means for controlling a throttle opening of the first variable throttle device based on a comparison result of the sixth comparing means.