JPH0968359A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control temperature in an air conditioned space and degree of superheat of refrigerant at a compressor intake in a well balanced manner. SOLUTION: For the purpose of controlling temperature in an air conditioned space a first travel determining means 16a determines travel of an application side expansion valve 8a, and for the purpose of controlling degree of superheat of refrigerant at an outlet of an application side heat exchanger a change amount of travel of the application side expansion valve 8a is calculated and a travel value determined by itself at a previous control is added to the calculated value. A second travel determining means 18a thereby determines a travel at the time of next control and a fuzzy operator 17a derives by calculation, from travel values determined by the two determining means by using a membership function having degree of superheat at the outlet of the application side heat exchanger as a parameter, the travel of the application side expansion valve 8a and controls the travel of the application side expansion valve 8a by using derived values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for performing well-balanced control between temperature control of an air-conditioned space and compressor suction superheat control of refrigerant.

[0002]

2. Description of the Related Art A heat source unit including a compressor, a heat source side heat exchanger, a heat source side expansion valve and the like and a plurality of use side units including a use side heat exchanger and a use side expansion valve are connected by piping. In the air conditioner, it is necessary to perform not only the temperature control of the air-conditioned space but also the compressor suction superheat degree control of the refrigerant in order to protect the compressor. When the device is a cooling machine, the temperature control of the air-conditioned space and the control of the refrigerant use side heat exchanger outlet (compressor suction) superheat degree are performed by opening and closing the use side expansion valve, and In the case of a heater, the temperature control of the air-conditioned space is performed by opening / closing the utilization side expansion valve, and the control of the refrigerant suction superheat degree of the refrigerant is mainly performed by opening / closing the heat source side expansion valve.

Conventionally, as the above-mentioned control in the case of an air conditioner, a method is known in which a fuzzy logic is used and a membership function shown in FIG.
No. 204568). In the above conventional method, the air-conditioned space temperature control device (PID type) calculates the amount of change in the opening degree of the use-side expansion valve so that the detected temperature of the air-conditioned space matches the set temperature, and the current (previous control Time)) to determine the next use-side expansion valve opening, and the use-side superheat degree control device (PID type) detects the detected use-side heat exchanger outlet superheat degree. The amount of change in the opening of the expansion valve on the use side is calculated so that it matches the set superheat degree, and the current
To the next use-side expansion valve opening degree. Then, as shown in FIG. 6, when the superheat degree at the time of detection is equal to or higher than the optimum superheat degree Tdes, the actual opening / closing operation of the use side expansion valve is performed only by the use side expansion valve opening determined by the air conditioning space temperature control device. Performed, minimum allowable superheat Tmi
In the case of n or less, the actual use-side expansion valve opening / closing operation is performed only by the use-side expansion valve opening determined by the use-side superheat degree control device to obtain the optimum superheat degree Tdes and the minimum allowable superheat degree Tmin.
In the case of between, the actual opening / closing operation of the usage-side expansion valve was performed by the opening calculated by fuzzy calculation based on the two usage-side expansion valve openings determined by both control devices.

Further, conventionally, the above-mentioned control in the case of a heater is performed by detecting the superheat degree of refrigerant suction into the compressor, and detecting the physical quantity of the refrigerant in front of the compressor suction port (compressor inlet temperature and heat source side heat exchanger inlet). Temperature, the suction pressure and suction temperature of the compressor, etc.), and the heat source side expansion valve is opened / closed so that the obtained superheat degree matches the target superheat degree (for example, JP-A-4-203854). Issue).

[0005]

However, in the case of the air conditioner, when the operation is performed by the above conventional control method, the superheat degree is between the optimum superheat degree Tdes and the allowable minimum superheat degree Tmin, and the air conditioning space temperature is When the direction of change in the opening degree of the use side thermal expansion valve calculated by the control device and the direction of change in the use side heat expansion valve opening degree calculated by the use side heat exchanger outlet superheat degree control direction are opposite directions, actual control is performed. The opening degree of the usage-side expansion valve is a value between the opening degrees determined by both control devices, and the opening change amount is smaller than the change amount calculated by both control devices. Its integration effect diminishes,
The controllability seen from both control devices becomes low. In particular, the controllability on the side of the usage-side heat exchanger outlet superheat degree control device becomes low, so that the usage-side heat exchanger outlet superheat degree is rather low.
However, there is a problem that the temperature control of the air-conditioned space, which is the original purpose of the apparatus, cannot be properly performed.

On the other hand, in the case of a heater, when the heat source side expansion valve is controlled by the above-mentioned conventional method, the compressor suction superheat degree of the refrigerant does not become less than zero. Therefore, even if the dryness degree is small, it is controlled. The deviation does not become larger than that when the superheat degree is zero, and therefore a sufficient control operation cannot be performed, so that there is a problem that the compressor suction superheat degree cannot be easily matched with the target value. If the compressor intake superheat does not match the target value, the opening / closing control of the difference between the target value and the detected value will always be performed, so the opening / closing operation of the heat source side expansion valve will be performed suddenly or more frequently than necessary. Therefore, there is a problem that the refrigeration cycle is difficult to stabilize. Further, when the compressor suction superheat degree matches the target value, the opening degree of the heat source side expansion valve is not changed.For example, when the usage side expansion valve is fully opened and more refrigerant is needed. However, there is also a problem that sufficient refrigerant is not supplied to the use side unit.

In view of the above problems, the present invention promptly terminates the use side heat exchanger outlet superheat degree control in the air conditioner when the use side heat exchanger outlet superheat degree is in the fuzzy region. An object of the present invention is to provide an air conditioner capable of shifting to temperature control of space. Further, in the present invention, even if the compressor suction superheat degree of the refrigerant is zero in the heater, the control operation is performed according to the refrigerant dryness at that time, so that the compressor suction superheat is promptly performed. It is an object of the present invention to provide an air conditioner that can control the heat source side expansion valve in consideration of the temperature control state of the air-conditioned space, in addition to realizing a stable refrigeration cycle by setting the temperature within an appropriate range. And

[0008]

In order to achieve the above object, an air conditioner according to claim 1 is a heat source unit having a compressor, a heat source side heat exchanger, a use side expansion valve, and a use side heat exchanger. One or more user side units having
The gas side pipe connecting both units, the liquid side pipe, the refrigerant compressed by the compressor, after heat exchange with the outside air in the heat source side heat exchanger, the liquid side pipe and the use side expansion After flowing into the heat exchanger on the use side through a valve and exchanging heat with the air in the air-conditioned space in which the user unit on the use side is installed, the compressor is passed through the gas side pipe. In an air conditioner having a refrigerant circuit configured to recirculate into the air conditioner, an air conditioning space temperature detecting means for detecting a temperature of the air conditioning space, a target temperature setting means for setting a target temperature of the air conditioning space, and the refrigerant Use side heat exchanger outlet superheat detection means for detecting the superheat degree at the outlet of the use side heat exchanger, a target superheat degree setting means for setting a target superheat degree at the outlet of the use side heat exchanger of the refrigerant, and Air conditioning space temperature detection First opening degree determining means for determining an opening degree value of the use side expansion valve so that the air-conditioned space temperature detected by the stage becomes equal to the temperature set by the target temperature setting means, and the use side heat exchanger The opening change amount of the use-side expansion valve is calculated so that the superheat degree detected by the outlet superheat degree detecting means becomes equal to the target superheat degree set by the target superheat degree setting means, and the calculated value is calculated at the time of the previous control. Second opening degree determining means for determining the opening value of the usage-side expansion valve at the next control by adding the opening value of the usage-side expansion valve determined by itself, and the usage-side heat exchanger outlet overheat When the degree of superheat detected by the degree detecting means is smaller than the first threshold value and is larger than the second threshold value, the opening value determined by the second opening determining means is used. The usage-side heat exchanger is controlled by controlling the opening degree of the usage-side expansion valve. Superheat detecting mouth superheat degree detecting means is greater than the third threshold value between the first and second thresholds, and the third threshold value the second
Less than the fourth threshold between the thresholds of
The opening degree of the utilization side expansion valve is controlled using the opening degree value determined by the first opening degree determining means, and the superheat degree detected by the utilization side heat exchanger outlet superheat degree detecting means is the first level. If it is between the threshold value and the third threshold value and between the fourth threshold value and the second threshold value, both opening degrees determined by the first and second opening degree determining means Control means for controlling the opening degree of the utilization side expansion valve using an opening degree value obtained from a membership function based on the value of superheat.

As a result, the first opening degree determining means determines the opening degree value of the utilization side expansion valve so that the air conditioning space temperature becomes equal to the target temperature, and the second opening degree determining means determines the utilization side heat exchanger. Calculate the amount of change in the opening of the expansion valve on the use side so that the outlet superheat becomes equal to the target superheat, add the calculated opening value to the calculated value, and then add The opening value is determined, and the superheat degree at the refrigerant use side heat exchanger outlet is the first
Is smaller than the threshold value or larger than the second threshold value, the opening degree of the use side expansion valve is controlled according to the opening degree value determined by the second opening degree determining means, and the refrigerant side heat exchange is performed. When the outlet superheat degree is larger than the third threshold value and smaller than the fourth threshold value, the opening degree of the utilization side expansion valve is controlled by the opening degree value determined by the first opening degree determining means, When the refrigerant use side heat exchanger outlet superheat degree is between the first threshold value and the third threshold value or between the fourth threshold value and the second threshold value, The opening control of the use-side expansion valve is performed based on the opening values obtained by the membership function having the degree of superheat as a variable from the opening values determined by the 1 and 2 opening determining means. Therefore, when the usage-side heat exchanger outlet superheat degree is not equal to the target superheat degree, the opening degree value determined by the second opening degree determining means is equal to the opening degree change amount calculated from the actual target opening degree value. When the opening value is a large (or small) value and is used for controlling the opening of the usage-side expansion valve, the controllability by the opening value is high, and in particular, the usage-side heat exchanger outlet superheat degree is When it is between the first threshold value and the third threshold value or between the fourth threshold value and the second threshold value, the second degree-of-opening deciding means promptly performs the target superheat degree control. After that, the superheat degree at the outlet of the heat exchanger on the use side can be set between the third threshold value and the fourth threshold value, and the first opening degree determining means shifts to the intended air conditioning space temperature control. can do.

The air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect, wherein the second opening degree determining means and the utilization side heat exchanger outlet superheat degree detecting means further detect. During the first control after the state in which the degree of superheat is in the proper range larger than the third threshold value and smaller than the fourth threshold value is outside the proper range for a certain period of time or longer, the self-determination is made. The opening value of the usage-side expansion valve for the next control is determined by using the opening value of the usage-side expansion valve determined by the first opening determination means during the previous control instead of the opening value of the usage-side expansion valve It has a degree-of-opening determination part.

As a result, the state in which the superheat degree at the outlet of the heat exchanger of the use side of the refrigerant is in the proper range continues for a certain period of time, that is, the opening degree of the use side expansion valve is determined by the opening degree value determined by the first opening degree determining means. After the control is continued for a certain period of time or more, the superheat degree at the outlet of the heat exchanger on the use side is out of the proper range.
When the control by the opening degree determining means is restarted, at the time of the first control after the restart, the second opening degree determining means causes the utilization side expansion valve so that the utilization side heat exchanger outlet superheat degree becomes equal to the target superheat degree. The opening change amount of the use side expansion valve is calculated by adding the opening change amount of the use side expansion valve to the calculated value at the time of the previous control. Therefore, even if the opening degree of the usage-side expansion valve is largely changed by the room temperature control of the first opening degree determining means while the usage-side heat exchanger outlet superheat degree is within the proper range, the usage side by the second opening degree determining means is changed. Since the control integration effect of the superheat degree control is removed, when the use side superheat degree control by the second opening degree determining means is restarted, the use side superheat degree control can be smoothly restarted.

The air conditioner according to a third aspect of the present invention is one or more including a heat source unit having a compressor, a heat source side heat exchanger, and a heat source side expansion valve, and a use side expansion valve and a use side heat exchanger. Of the use side unit, a gas side pipe connecting the both units, a liquid side pipe, the refrigerant compressed by the compressor is sent to the use side unit via the gas side pipe, The refrigerant is heat-exchanged with the air in the air-conditioned space in which the usage-side unit is arranged in the usage-side heat exchanger, and then through the usage-side expansion valve, the liquid-side pipe, and the heat-source-side expansion valve. In an air conditioner configured to flow into the use-side heat exchanger, exchange heat with the outside air in the use-side heat exchanger, and then return to the compressor, the compressor discharge overheat of the refrigerant. Compressor discharge superheat detection Means, a target superheat degree setting means for setting a target superheat degree of the refrigerant at the discharge port of the compressor, and a superheat degree detected by the compressor discharge superheat degree detecting means are set by the target superheat degree setting means. The heat source side expansion valve opening degree determining means for determining the opening degree value of the heat source side expansion valve so as to be equal to the superheat degree, and the superheat degree detected by the compressor discharge superheat degree detecting means are higher than a first threshold value. If small,
And when it is larger than the second threshold value, the opening degree of the heat source side expansion valve is controlled by using the opening degree value determined by the heat source side expansion valve opening degree determining means, and the compressor discharge overheat is controlled. The degree of superheat detected by the degree detecting means is larger than the third threshold value between the first threshold value and the second threshold value, and the superheat degree between the third threshold value and the second threshold value is When it is smaller than the fourth threshold value, the opening degree of the heat source side expansion valve is controlled so as to maintain the current opening value, and the superheat degree detected by the compressor discharge superheat degree detecting means is the first. Between the third threshold and
If it is between the fourth threshold value and the second threshold value, the degree of superheat is calculated from the current opening value and the opening value determined by the heat source side expansion valve opening determining means. And a control means for controlling the opening degree of the heat source side expansion valve by using the opening degree value obtained by the membership function as a variable.

Thus, the heat source side expansion valve opening degree determining means determines the opening degree value of the heat source side expansion valve so that the refrigerant compressor discharge superheat degree becomes equal to the target superheat degree, and the refrigerant compressor discharge superheat degree. When the degree is smaller than the first threshold value or larger than the second threshold value, the heat source side expansion valve opening / closing control is performed according to the opening value determined by the heat source side expansion valve opening degree determining means. If the compressor discharge superheat degree of the refrigerant is larger than the third threshold value and smaller than the fourth threshold value, the heat source side expansion valve is controlled to open and close so as to maintain the current opening value, If the compressor discharge superheat degree is between the first threshold value and the third threshold value or between the fourth threshold value and the second threshold value, Membership function with the degree of superheat as a variable from the opening value determined by the heat source side expansion valve opening degree determining means Since the opening control of the heat source side expansion valve by more the obtained opening values, never closing operation of the heat source side expansion valve is frequently or rapidly performed unnecessarily.

The air conditioner according to claim 4 is different from the air conditioner according to claim 3 in that the opening state of the use-side expansion valve is detected and the heat source-side expansion valve is opened according to the opening state. An opening adjustment means for determining an opening value is provided, and in the control means,
The opening value determined by the opening adjusting means is used instead of the current opening value. Thereby, the opening degree adjusting means determines the opening degree value of the heat source side expansion valve according to the opening degree state of the utilization side expansion valve, and the heat source side expansion valve opening degree determining means determines the compressor discharge superheat degree of the refrigerant. The opening degree value of the heat source side expansion valve is determined so as to be equal to the target superheat degree, and when the refrigerant compressor discharge superheat degree is smaller than the first threshold value or larger than the second threshold value, The opening degree value of the heat source side expansion valve opening degree determining means controls the opening and closing of the heat source side expansion valve, and the compressor discharge superheat degree of the refrigerant is larger than the third threshold value and larger than the fourth threshold value. If it is smaller, the heat source side expansion valve is opened / closed by the opening value determined by the opening adjustment means, and the refrigerant compressor discharge superheat degree is between the first threshold value and the third threshold value. Alternatively, when it is between the fourth threshold value and the second threshold value, the opening value determined by the opening adjusting means. From the opening value determined by the heat source side expansion valve opening determining means, the opening degree of the heat source side expansion valve is controlled by the opening value obtained by the membership function having the degree of superheat as a variable. It is possible to effectively prevent insufficient supply of the refrigerant to the unit.

The air conditioner according to claim 5 is different from the air conditioner according to claim 4 in that the opening degree adjusting means is
When at least one opening of the use side expansion valve is fully opened,
The opening degree value of the heat source side expansion valve is determined by adding a certain opening degree to the current opening degree of the heat source side expansion valve. With this, when at least one opening of the use-side expansion valve is fully opened, the opening adjustment means adds a certain opening to the current opening of the heat-source-side expansion valve to determine the opening value of the heat-source-side expansion valve. The heat source side expansion valve opening degree determining means determines the opening value of the heat source side expansion valve so that the compressor discharge superheat degree of the refrigerant becomes equal to the target superheat degree, and the compressor discharge superheat degree of the refrigerant is When it is smaller than the first threshold value or larger than the second threshold value, the heat source side expansion valve opening / closing control is performed according to the opening value determined by the heat source side expansion valve opening degree determining means, and the refrigerant is compressed. When the machine discharge superheat degree is larger than the third threshold value and smaller than the fourth threshold value,
The opening / closing control of the heat source side expansion valve is performed according to the opening value determined by the opening adjustment means, and the refrigerant compressor discharge superheat degree is between the first threshold value and the third threshold value or the fourth threshold value. When it is between the threshold value and the second threshold value, the degree of superheat is calculated from the opening value determined by the opening adjustment means and the opening value determined by the heat source side expansion valve opening determination means. Since the opening degree of the heat source side expansion valve is controlled by the opening degree value obtained by the membership function as a variable, it is possible to effectively prevent the supply shortage of the refrigerant to the usage side unit.

[0016]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an overall configuration diagram of an air conditioner according to an embodiment of the present invention. As shown in the figure, the present apparatus is roughly classified into a heat source unit 5 and a use side unit group 6 including three use side units 6a, 6b, 6c respectively arranged in three air-conditioned spaces A, B, and C.
And a gas line 13 and a liquid side line 14 that connect the two.

As shown in FIG. 1, the heat source unit 5 includes a compressor 1, a four-way valve 2, a heat source side heat exchanger 3, a heat source side blower fan 3a, a heat source side expansion valve 8, an accumulator 4, and a discharge superheat degree. A detector 27, a discharge superheat degree target setting device 28, and a heat source side expansion valve opening degree control device 50 are provided. User side unit group 6
The three use side units 6a, 6b, 6c constituting the
Both have the same configuration, so here, the user side unit 6
The description will be made with a as a representative. As shown in FIG. 1, the usage-side unit 6a includes a usage-side heat exchanger 7a and a usage-side expansion valve 8
a, user side blower fan 11a, air conditioning space temperature sensor-1
0a, air conditioning temperature setting device 15a, use side heat exchanger outlet superheat detector 20a, use side superheat degree target setting device 21a, use side expansion valve opening control device 30a during cooling operation, use side expansion valve opening during heating operation A degree control device 40a is provided.

In the air conditioner of the above construction, during the cooling operation, the refrigerant compressed by the compressor 1 is regulated by the four-way valve 2 in the direction of the arrow indicated by the dotted line.
It flows into the heat source side heat exchanger 3, where it exchanges heat with the outside air sent by the heat source side blower fan 3a and condenses to become a liquid refrigerant. The refrigerant that has exited the heat source side heat exchanger 3 passes through the heat source side expansion valve 8 that is fully opened, and the liquid side conduit 14 causes the refrigerant to flow in accordance with the opening degree of each of the use side expansion valves 8a, 8b, and 8c. It is distributed to the respective use side units 6a, 6b, 6c. The distributed refrigerant is decompressed by the use-side expansion valves 8a, 8b, 8c to become a gas / liquid two-phase refrigerant.
It flows into a, 7b, and 7c. Each user side heat exchanger 7a, 7
In b and 7c, the refrigerant is the blower fans 11a and 11 on the use side.
b, 11c exchanges heat with the air in the air-conditioned space, evaporates to become a gas refrigerant, passes through the gas side pipeline 13, and passes through the four-way valve 2
To the compressor 1 via the accumulator 4.

On the other hand, during the heating operation, the flow of the refrigerant compressed by the compressor 1 is regulated by the four-way valve 2 in the direction of the arrow shown by the solid line, and through the gas side pipe 13, each air conditioning space temperature sensor-10a, The temperature of each air-conditioned space A, B, C detected by 10b, 10c and each air-conditioning temperature setter 15a, 15
From the difference between the temperatures set in b and 15c, according to the opening degree of each of the use side expansion valves 8a, 8b, 8c determined by the heating side use side expansion valve opening degree control devices 40a, 40b, 40c, It is distributed to the respective use side units 6a, 6b, 6c. The distributed refrigerant is used by each of the use side heat exchangers 7a, 7a.
b and 7c, each of the use side blower fans 11a, 11b, 11
The heat exchange is performed with the air in the air-conditioned space, which is condensed into a liquid refrigerant, which is decompressed according to the opening degree of each of the use-side expansion valves 8a, 8b, 8c, and passes through the liquid-side conduit 14 to the heat source side. It flows into the expansion valve 8. In the heat source side expansion valve 8, the refrigerant is further decompressed according to its opening degree, becomes a gas / liquid two-phase refrigerant, and flows into the heat source side heat exchanger 3. The refrigerant exchanges heat with the outside air sent by the heat-source-side blower fan 3a in the heat-source-side heat exchanger 3, evaporates to become a gas refrigerant, and passes through the four-way valve 2 and the accumulator 4 to the compressor 1. Bring to reflux.

The above is 1 in the cooling operation and the heating operation when the refrigerant circulates while changing the ideal state.
It is a cycle. The temperature control of the air-conditioned space and the compressor suction superheat control of the refrigerant will be described below separately for the cooling operation and the heating operation. (Cooling Operation) The usage side expansion valve opening / closing control during the cooling operation will be described by taking the usage side unit 6a as an example. In Figure 2,
The block diagram of the use side expansion valve opening / closing control system at the time of cooling operation of the use side unit 6a is shown.

As shown in the figure, the use side expansion valve opening / closing control system during the cooling operation includes an air conditioning space temperature sensor 10a, an air conditioning temperature setting device 15a, and a use side heat exchanger outlet superheat detector 20.
a, a use side superheat degree target setting device 21a, and a use side expansion valve opening degree control device 30a during cooling operation. The air-conditioned space temperature sensor-10a measures the air temperature at the air inlet of the use side blower fan 11a.

The air conditioning temperature setting device 15a is used by the user of the apparatus to set a desired temperature of the air conditioning space, and a known temperature setting device is used. The utilization side heat exchanger outlet superheat degree detector 20a indicates the utilization side heat exchanger outlet superheat degree which is the difference between the utilization side heat exchanger outlet temperature and the inlet temperature of the refrigerant detected by a temperature sensor (not shown). It is a device for detecting.

The utilization side superheat degree target setter 21a is considered to be most suitable in consideration of the efficiency of the utilization side heat exchanger and the operational stability of the refrigeration cycle, and the degree of superheat of the refrigerant at the outlet of the utilization side heat exchanger. A known temperature setter is used to set the temperature. As the set value, a certain degree of superheat within the appropriate range of the degree of superheat at the outlet of the heat exchanger on the use side described later is used.

Expansion valve opening control device 30 on the utilization side during cooling operation
a is the air conditioning space temperature detected by the air conditioning space temperature sensor 10a, the set temperature set by the air conditioning temperature setting device 15a, and the use side heat exchanger outlet detected by the use side heat exchanger outlet superheat detector 20a. This is a device for controlling the opening degree of the use-side expansion valve based on the superheat degree and the degree of superheat of the refrigerant at the use-side heat exchanger outlet set by the use-side superheat degree target setting device 21a. And the first opening determiner 16a
And a second previous value storage unit 24a, a second opening degree determination unit 18a, a fuzzy computing unit 17a, and a storage content change unit 31a.

The first previous value storage unit 22a is a device for storing the opening degree Uaz of the expansion valve 8a on the utilization side each time the opening / closing control of the expansion valve 8a is controlled. The use-side expansion valve 8a is 0% (fully closed) to 1
It has an operating range of 00% (fully open). First opening determiner 1
6a adjusts the temperature of the air-conditioned space A detected by the air-conditioned space temperature sensor 10a from the current opening degree of the use-side expansion valve 8a so as to match the set temperature set by the air-conditioning temperature setting device 15a. The amount of change is calculated, and the calculation result is the first
This is for determining the next opening U1a of the use side expansion valve 8a by adding it to the value Uaz stored in the previous value storage 22a, and a known speed type PID controller is used. In addition, at the time of starting this device, the first opening determiner 16a
Is set to output U1a = 80%.

The second previous value storage device 24a is a device for storing the value U2az each time the second opening degree determiner 18a determines the opening degree of the use side expansion valve 22a. The memory content is set to U2az = 80%. The second opening degree determiner 18a includes a utilization side heat exchanger outlet superheat degree detector 20.
Utilization side heat exchanger outlet superheat degree SHa detected by a
However, when it is out of the appropriate range described later, the utilization side heat exchanger outlet superheat degree SHa is made to match the superheat degree of the refrigerant at the utilization side heat exchanger outlet set by the utilization side superheat degree target setting device 21a. In addition, the change amount of the opening degree of the use-side expansion valve 8a is calculated, and the calculation result is added to the value U2az stored in the second previous value storage unit 24a.
It is for determining the next opening U2a of a, and a known speed type PID controller is used. The second opening degree determiner 18a is set to output U2a = 80% when the apparatus is started.

The fuzzy calculator 17a uses the opening U1a determined by the first opening determiner and the opening U2a determined by the second opening determiner to determine the outlet of the utilization side heat exchanger shown in FIG. This is a device for determining the actual operation control opening of the expansion valve on the utilization side based on a fuzzy membership function having the degree of superheat as a variable, and a known arithmetic device composed of a microprocessor or the like is used. Fuzzy member for air conditioning space temperature control
The ship function φ1a and the fuzzy member-ship function φ2a of the user side heat exchanger outlet superheat degree are given by the following equations, for example.

[0028]

[Equation 1]

[0029]

(Equation 2) Then, using the above function, the operation control opening degree of the actual expansion valve on the use side is calculated by the following equation. Ua = φ1a × U1a + φ2a × U2a In addition, the threshold values F1a to F4a of the elements are the relationship between the efficiency of the heat exchanger on the use side and the superheat degree at the outlet of the heat exchanger on the use side of the refrigerant, and the operation stability of the refrigeration cycle, etc. In consideration of the following, set F1a = 0, F2a = 5, F3a = 15, F4a = 25, and set F1a to F4a as the allowable range of the superheat degree at the outlet of the heat exchanger on the use side, and use the range from F2a to F3a. The superheat degree at the outlet of the side heat exchanger should be within the appropriate range.

The memory content changer 31a stores the opening Uaz of the use side expansion valve 8a at the time of the previous control, and the use side heat exchanger outlet superheat degree is within a proper range continuously for a certain time Ta or more. In other words, in other words, the opening degree Ua of the use side expansion valve 8a is determined only by the first opening degree determiner (φ
1a = 1, φ2a = 0) time continues for a certain time Ta or more, U2a stored in the second previous value storage 24a
z is changed to the opening degree Uaz of the use side expansion valve 8a at the time of the previous control. The fixed time Ta is optimally the time corresponding to the response time of the change in the superheat degree at the outlet of the heat exchanger on the use side, and is, for example, 2 minutes.

The control contents of the utilization side thermal expansion valve opening / closing control system having the above construction will be described with reference to specific numerical examples. First, when the device is started, the first opening determiner 16a and the second opening determiner 18a output U1a = 80% and U2a = 80%, respectively. Ua = 80% regardless of the value of the superheat degree at the outlet of the heat exchanger on the use side.

In order to lower the temperature of the air-conditioned space A at the time of the first control after startup, the first opening determiner 16a
As a variation of the opening degree of the usage-side expansion valve 8a, it is calculated to open 20%. On the other hand, in order to raise the usage-side heat exchanger outlet superheat degree, the second opening degree determiner 18a causes the usage-side expansion valve 8a to open. Assuming that the use side heat exchanger outlet superheat degree SHa at that time is calculated to be 20% closed as the degree change amount, the use side expansion valve 8a determined by the first opening degree determiner 16a is calculated. The opening U1a is U1a = Uaz + 20 = 80 + 20 = 100%, and the opening U2a of the use side expansion valve 8a determined by the second opening determiner 18a is U2a = U2az-20 = 80-20 = 60%. . Further, from Equations 1 and 2, since φ1a = 0.5 and φ2a = 0.5, the utilization side expansion valve opening Ua finally obtained by the fuzzy calculator 17a is Ua = φ1a × U1a + φ2a × U2a = 0.5 × 100 + 0.5 × 60 = 80%, and the initial opening is maintained. At this time point, Uaz = 80% is stored in the first previous value storage unit 22a, and U2az = 60% is stored in the second previous value storage unit 24a.

Then, at the time of the next second control, as in the previous (first) control, the first opening determiner 16a.
Is calculated to open 20%, and the second opening degree determiner 18a
Calculated to close 20%, and the outlet superheat degree SH at that time
Assuming that a is 2.5K, the first opening determiner 16a
The opening U1a of the usage-side expansion valve 8a determined by is U1a = Uaz + 20 = 80 + 20 = 100%, and the opening U2a of the usage-side expansion valve 8a determined by the second opening determiner 18a is U2a = U2az-20. = 60-20 = 40%. Further, from Equations 1 and 2, φ1a = 0.5 and φ2a = 0.5, so the usage-side expansion valve opening Ua finally obtained by the fuzzy calculator 17a is Ua = φ1a × U1a + φ2a × U2a = 0.5 × 100 + 0.5 × 40 = 70%, the use side expansion valve 8a is closed by 10%, and the opening degree becomes 70%.

Therefore, the opening degree calculated by the first opening degree determiner 16a for controlling the temperature of the air-conditioned space and the second opening degree determiner 18a for controlling the outlet side superheat degree (compressor suction) of the use side heat exchanger. Although the degree change amount is the same between the first control and the second control after the device is started,
The opening is maintained, and the opening is closed by 10% during the second control.

That is, a value obtained by adding the opening change amount to the current (previous control) opening is input to the fuzzy calculator 17a from the first opening determiner 16a, and the second opening determiner 18a.
Since the value obtained by adding the opening change amount to the opening degree determined by the previous control is input, the control operation of the second opening degree determiner 18a is integrated and the controllability thereof is improved. become.

After that, the superheat degree SHa at the outlet of the heat exchanger on the use side
Is 7K, and the first opening determiner 16a calculates to maintain the current opening, and that state continues,
During this time, the second opening degree determiner 18a does not perform calculation. Therefore, the opening U2az is 40% in the second previous value memory 24a.
Is still remembered. Within 2 minutes (constant time Ta = 2 minutes), the user side heat exchanger outlet superheat degree SHa is 2.
5, the first opening degree determiner 16a calculates to maintain the opening degree, and the second opening degree determiner calculates 20 degrees.
%, The opening Uaz of the use-side expansion valve 8a in the previous control is 70%, so the opening U1a of the use-side expansion valve 8a determined by the first opening determiner 16a.
Is U1a = Uaz + 0 = 70 + 0 = 70%, and the opening U2a of the utilization side expansion valve 8a determined by the second opening determiner 18a is U2a = U2az-20 = 40-20 = 20%. Further, from Equations 1 and 2, φ1a = 0.5 and φ2a = 0.5, so the usage-side expansion valve opening Ua finally obtained by the fuzzy calculator 17a is Ua = φ1a × U1a + φ2a × U2a = 0.5 × 70 + 0.5 × 20 = 45%, and the use-side expansion valve 8a is closed by 25% to 45% due to the control integration effect of the use-side superheat degree control.

However, when the above-mentioned utilization side heat exchanger outlet superheat degree SHa of 7K continues for 2 minutes or more, the value stored in the second previous value storage unit 24a becomes
U2az = Uaz = 70% is changed by the memory content changer 31a. After that, the use side heat exchanger outlet superheat degree changes to 2.5K, the first opening degree determiner 16a is operated to maintain the opening degree, and the second opening degree determiner closes 20%. If it is calculated as
Since the opening Uaz in the previous control of a is 70%, the first
The opening U1a of the use-side expansion valve 8a determined by the opening determiner 16a is U1a = Uaz + 0 = 70 + 0 = 70%, and the opening U2a of the use-side expansion valve 8a determined by the second opening determiner 18a is , U2a = U2az-20 = 70-20 = 50%. Further, from Equations 1 and 2, φ1a = 0.5 and φ2a = 0.5, so the usage-side expansion valve opening Ua finally obtained by the fuzzy calculator 17a is Ua = φ1a × U1a + φ2a × U2a = 0.5 × 70 + 0.5 × 50 = 60%, and the use-side expansion valve 8a is closed 10% because the control integration effect of the use-side superheat control is canceled.
It becomes 0%.

That is, the user side heat exchanger outlet superheat degree SHa
Is continuously within the proper range for 2 minutes or more, it is determined that the use side heat exchanger outlet superheat degree SHa is settled, and the opening degree stored in the second previous value storage unit 24a is The changer 31a changes the opening degree of the use-side expansion valve 8a during the previous control, and the control integration effect of the control operation of the second opening degree determiner 18a is canceled.

While the outlet-side superheat degree SHa of the use-side heat exchanger is settled, the use-side expansion valve 8 is controlled by controlling the temperature of the air-conditioned space.
If the opening of a is too far from the opening stored in the second previous value storage 24a, or if the opening of the use-side expansion valve 8a and the second previous value storage 24a are opened. Even if the usage-side heat exchanger outlet superheat degree SHa deviates from the proper range after the magnitude relationship has been reversed, the opening degree of the usage-side expansion valve 8a calculated by the second opening degree determiner 18a The value of does not unnecessarily change the opening degree of the use-side expansion valve 8a. Further, the control operation opposite to the original control operation is not performed, and the control of the utilization side heat exchanger outlet superheat degree SHa is smoothly restarted.

As described above, during the cooling operation, even if the use side heat exchanger outlet superheat degree is within the allowable range and outside the appropriate range, the control integration effect is added to the use side superheat degree control to increase the control strength. Therefore, it is possible to quickly shift to the control of only the temperature of the air-conditioned space without stopping the outlet superheat within the allowable range and outside the proper range for a long time.
Efficient operation becomes possible.

Further, since the controllability of the outlet superheat degree control changes by itself due to the control integration effect, it is possible to relatively easily set the relationship between the temperature control of the air-conditioned space and the controllability of the superheat degree control. Further, depending on how long the usage-side heat exchanger outlet superheat degree SHa is within the proper range, whether the use-side heat exchanger outlet superheat degree SHa has transiently entered the proper range or has been settled to the proper range. Judge,
When it can be determined that the heat has entered transiently, when the use-side superheat degree control is performed again, the use-side heat exchanger outlet superheat degree SHa can be quickly put into an appropriate range by the control integration effect. On the other hand, when it can be determined that the user side has been settled, by canceling the integrated opening degree value, the use side superheat degree does not depend on the opening degree of the use side expansion valve 8a that has changed due to the temperature control of the air-conditioned space. Control can be resumed smoothly. (During heating operation) FIG. 4 shows a block diagram of the heat source side expansion valve opening / closing control system during heating operation.

As shown in the figure, the heat source side expansion valve opening / closing control system during the heating operation includes the utilization side expansion valve opening degree control devices 40a, 40b, 40c and the compressor discharge superheat degree detector 27 during the heating operation.
And a compressor discharge superheat degree target setting device 28 and a heat source side expansion valve opening degree control device 50. The heating-side use side expansion valve opening degree control devices 40a, 40b, 40c include an air conditioning temperature setting device 15a corresponding to the temperatures of the air conditioning spaces A, B, C detected by the air conditioning space temperature sensors 10a, 10b, 10c. The use-side expansion valves 8a and 8a are arranged so that the respective deviations from the respective set temperatures set in 15b and 15c are reduced.
This is a device for controlling the opening degrees of b and 8c, and is a known speed type P
In this control system, the opening degree adjuster 2 which will be described later is constituted by an ID controller, and the opening degrees U3a, U3b, U3c of the use-side expansion valves 8a, 8b, 8c, which are determined at each control, are changed in each case.
Output to 9.

The compressor discharge superheat detector 27 is a compressor 1 which is detected by a pressure sensor (not shown) and a temperature sensor (not shown) of the refrigerant near the discharge port of the compressor 1. Is a device for detecting the degree of superheat SHd of the refrigerant near the discharge port of the compressor 1 from the temperature of the refrigerant near the discharge port. Here, since the compressor discharge superheat degree of the refrigerant and the compressor suction superheat degree and the dryness degree are experimentally and empirically associated, by indirectly detecting the compressor discharge superheat degree, Compressor suction superheat or dryness will be detected.

The compressor discharge superheat target setting unit 28 sets the compressor discharge superheat corresponding to the compressor intake superheat which seems to be most suitable in consideration of the operation stability of the refrigeration cycle. And is composed of a known temperature setting device. As the set value, a superheat degree within a proper range of a compressor discharge superheat degree described later is used. The heat source side expansion valve opening degree control device 50 has opening degrees U3a, U3b, U of the respective use side expansion valves 8a, 8b, 8c input from the heating side use side expansion valve opening degree control devices 40a, 40b, 40c.
3c and the compressor discharge superheat degree detected by the compressor discharge superheat degree detector 27 and the compressor discharge superheat degree set by the compressor discharge superheat degree target setter 28 to open and close the heat source side expansion valve. It is a device for performing the above, and is composed of a fourth previous value storage 19, an opening adjuster 29, a third previous value storage 23, a heat source side expansion valve opening determiner 16, and a fuzzy calculator 17.

The fourth previous value storage 19 is used for the heat source side expansion valve 8
This is a device for storing the opening degree Udz every time the opening / closing control is performed. The heat source side expansion valve 8 is 0% (fully closed) to 100%.
% (Fully open) operating range. The opening degree adjuster 29 includes the expansion valve opening degree control devices 40a, 40b, 4 for the utilization side during heating operation.
0c, the opening degree U3a, U3b, U3c of each use side expansion valve 8a, 8b, 8c is discriminated, and each use side expansion valve 8
When at least one of a, 8b, and 8c has an opening of 100% (fully open), the current (previously controlled) opening Udz of the heat source side expansion valve 8 stored in the fourth previous value storage 19 is set. When a constant opening is added to determine the next opening U2d, and none of the usage-side expansion valves 8a, 8b, 8c is fully open, the next opening U2d is set to the current (previous control time). ) Is a device that adopts and determines the opening Udz of the heat source side expansion valve 8).
In addition, when the present apparatus is started, the opening adjuster 29 sets U2d = 8.
It is set to output 0%. Moreover, 1% is set as a fixed opening degree.

The third previous value storage unit 23 is a device for storing the value U1dz every time the heat source side expansion valve opening degree determiner 16 determines the opening degree of the heat source side expansion valve 8. The heat source side expansion valve opening degree determiner 16 sets the compressor discharge superheat degree SHd of the refrigerant detected by the compressor discharge superheat degree detector 27 to the compressor discharge superheat degree target setter 28 that sets the compressor discharge superheat degree SHd. The amount of change in the opening degree of the heat source side expansion valve 8 is calculated so as to match the degree of superheat, and the calculation result is added to the value U1dz stored in the third previous value storage unit 23 to thereby increase the heat source side expansion valve 8
A known speed type PID controller is used to determine the next opening U1d of the. The heat source side expansion valve opening determiner 16 is set to output U1d = 80% when the present apparatus is started.

The fuzzy calculator 17 calculates the compressor discharge overheat shown in FIG. 5 from the opening U2d determined by the opening adjuster 29 and the opening U1d determined by the heat source side expansion valve opening determiner 16. Based on the fuzzy membership function with degree as a variable,
This is a device that determines the actual operation control opening degree of the heat source side expansion valve, and a known arithmetic device including a microprocessor or the like is used. The fuzzy membership φ1d for control by the opening determined by the heat source side expansion valve opening determiner and the fuzzy membership φ2d for control by the opening determined by the opening adjuster are given by, for example, the following equations.

[0048]

[Equation 3]

[0049]

[Equation 4] Then, using the above function, the operation control opening degree of the heat source side expansion valve that is actually performed is calculated by the following equation. Ud = φ1d × U1d + φ2d × U2d Further, the threshold values F1d to F4d of the elements are considered to be suitable in consideration of the operation stability of the refrigeration cycle, and the compressor discharge superheat degree associated with the compressor suction superheat degree considered to be suitable. Therefore, set F1d = 10, F2d = 15, F3d = 30, F4d = 50, set F1d to F4d as the allowable range of the compressor discharge superheat, and set F2d to F3d to the proper compressor discharge superheat. Range.

The control contents of the heat source side thermal expansion valve opening / closing control system having the above construction will be described with reference to specific numerical examples. First, when the present apparatus is started, the heat source side expansion valve opening degree determiner 16 and the opening degree adjuster 29 respectively output U1d = 80% and U2d = 80%, so the initial opening degree of the heat source side expansion valve is Ud = 80% regardless of the compressor discharge superheat value. At this point, U1dz = 80% is stored in the third previous value storage unit 23 and Udd is stored in the fourth previous value storage unit 19.
z = 80% is stored.

Next, the contents of the first control after the start of the apparatus will be described in three cases. (1) The heat source side expansion valve opening degree determiner 16 calculates so as to close the opening degree by 30%, and none of the use side expansion valves is in the fully opened state, and the compressor discharge superheat degree SHd is 11.5K. If there was.

The opening U1d of the heat-source-side expansion valve 8 determined by the heat-source-side expansion valve opening determiner 16 is U1d = U1dz-30 = 80-30 = 50%.

On the other hand, the opening U2d of the heat source side expansion valve 8 determined by the opening adjuster 29 is U2d = Udz = 80%. Further, from Equations 3 and 4, since φ1d = 0.7 and φ2d = 0.3, the heat source side expansion valve opening Ud finally obtained by the fuzzy calculator 17 is Ud = φ1d × U1d + φ2d × U2d = 0.7 × 50 + 80 × 0.3 = 59. (2) The heat source side expansion valve opening degree determiner 16 calculates so as to close the opening degree by 20%, and none of the use side expansion valves is in the fully opened state, and the compressor discharge superheat degree SHd is 20 deg. If.

The opening U1d of the heat-source-side expansion valve 8 determined by the heat-source-side expansion valve opening determiner 16 is U1d = U1dz-20 = 80-20 = 60%.

On the other hand, the opening U2d of the heat source side expansion valve 8 determined by the opening adjuster 29 is U2d = Udz = 80%. Further, from Equations 3 and 4, since φ1d = 0.0 and φ2d = 1.0, the heat source side expansion valve opening Ud finally obtained by the fuzzy calculator 17 is Ud = φ1d × U1d + φ2d × U2d = 0.0 × 60 + 80 × 1.0 = 80, and the initial opening is maintained. (3) The heat source side expansion valve opening degree determiner 16 calculates so as to close the opening degree by 20%, at least one of the use side expansion valves is in a fully opened state, and the compressor discharge superheat degree SHd is 20K. If.

The opening degree U1d of the heat source side expansion valve 8 determined by the heat source side expansion valve opening degree determiner 16 is U1d = U1dz-20 = 80-20 = 60%.

On the other hand, the opening U2d of the heat source side expansion valve 8 determined by the opening adjuster 29 is U2d = Udz + 1 = 81%. Further, from Equations 3 and 4, since φ1d = 0.0 and φ2d = 1.0, the heat source side expansion valve opening Ud finally obtained by the fuzzy calculator 17 is Ud = φ1d × U1d + φ2d × U2d = 0.0 × 60 + 81 × 1.0 = 81%, and the heat source side expansion valve is opened by 1% from the initial opening to 81%.

Therefore, only when the compressor discharge superheat degree is outside the appropriate range (F2d or less or F3d or more), the opening / closing control of the heat source side expansion valve is performed using the opening degree determined by the heat source side expansion valve opening degree determiner 16. If the discharge superheat is within the proper range, the heat source side expansion valve does not open / close by superheat control, so that the refrigeration cycle can be stabilized (example (2)). Even when the compressor discharge superheat degree is within the proper range, the heat source side expansion valve is opened at a constant opening when at least one of the usage side expansion valves is in the fully open state, so that the heating capacity due to the insufficient circulation amount of the refrigerant is increased. Can be prevented (example (3)).

Further, since the heat source side expansion valve is controlled to be opened / closed by detecting the compressor discharge superheat degree, even when the refrigerant at the compressor inlet is in a gas / liquid two-phase state, it is sufficient. The heat source side expansion valve can be opened and closed. In the above-described embodiment, in the opening adjuster 29, when at least one opening of the use side expansion valve is fully opened, 1% is added as a constant opening. Instead, the configuration may be such that the opening degree according to the opening degree state of the entire utilization side expansion valve is added.

Further, the number of the use side units is three, but the number is not limited to this, and may be one or two, and depending on the capacities of the compressor and the heat source side heat exchanger,
It can be more than that. Furthermore, the threshold values of the user side heat exchanger outlet superheat degree and the compressor discharge superheat degree, and the constant opening value added by the opening degree adjuster can be appropriately changed depending on the specifications of the heat exchanger, the compressor, etc. Needless to say.

The refrigerant used may be any one of a single composition, an azeotropic mixture and a non-azeotropic mixture.

[0062]

As described above, according to the air conditioner of the present invention, the second opening degree determining means expands the use side expansion so that the use side heat exchanger outlet superheat degree becomes equal to the target superheat degree. The valve opening change amount is calculated, and the valve opening value of the user side expansion valve for the next control is determined by adding the valve opening value that was self-determined during the previous control to the calculated value. When the degree of opening is not equal to the target degree of superheat, the opening degree value determined by the second opening degree determining means becomes a value larger (or smaller) by the opening degree change amount than the actual target opening degree value. That is, when the opening degree value determined by the second opening degree determining means is used for controlling the opening degree of the use-side expansion valve, the controllability by the opening degree value of the second opening degree determining means becomes high. The heat exchanger outlet superheat degree is between the first threshold value and the third threshold value or the fourth threshold value.
When it is between the threshold value of and the second threshold value, the second degree of opening determining means quickly ends the target superheat control,
The use-side heat exchanger outlet superheat degree can be set between the third threshold value and the fourth threshold value, and the first air-conditioning space temperature control can be performed by the first opening degree determining means. . Therefore, the temperature of the air-conditioned space can quickly reach the target temperature when the device is started or when the target temperature setting is changed, and after that, the target temperature can be effectively maintained, so that the comfortable air-conditioned space can be maintained. Can be realized.

According to the air conditioner of the second aspect of the present invention, the state in which the refrigerant use side heat exchanger outlet superheat degree is within the appropriate range continues for a certain period of time, that is, the first opening degree determining means. After the state in which the opening control of the usage-side expansion valve is performed by the opening value determined by is continued for a certain period of time or more, the usage-side heat exchanger outlet superheat degree is out of the appropriate range, and the control by the second opening determination means is restarted. Then, during the first control after the restart, the second opening degree determining means calculates the opening degree change amount of the usage-side expansion valve so that the usage-side heat exchanger outlet superheat degree becomes equal to the target superheat degree. Then, the opening value of the usage-side expansion valve is determined by adding the opening value of the usage-side expansion valve determined by the first opening determination means during the previous control to the calculated value. Therefore, while the usage-side heat exchanger outlet superheat degree is within the appropriate range for a certain period of time, the opening value of the usage-side expansion valve and the actual opening value of the usage-side expansion valve determined by itself before entering the appropriate range. Is greatly disregarded, or even if the magnitude relationship is reversed, the second opening degree determining means determines the use-side expansion valve determined by the first opening degree determining means during the first control after the control is restarted. Since the opening degree value of the utilization side expansion valve is determined using the opening degree value (actual opening degree value of the utilization side expansion valve), the utilization side superheat degree control can be restarted smoothly.

According to the air conditioner of the third aspect of the present invention, the compressor discharge superheat degree is detected, and the heat source side expansion valve opening degree determining means makes the detected superheat degree equal to the target superheat degree. Since the opening value of the heat source side expansion valve is determined, the control operation according to the dryness at that time can be performed even when the compressor suction superheat degree is zero, and the detected superheat degree is When it is larger than the third threshold value and smaller than the fourth threshold value, the opening degree value of the heat source side expansion valve is maintained and controlled,
When the detected degree of superheat is between the first threshold value and the third threshold value or between the fourth threshold value and the second threshold value, the current opening value and the heat source side The opening degree of the heat source side expansion valve is controlled by the opening degree value determined by the expansion valve opening degree determining means by the opening degree value obtained by the membership function having the degree of superheat as a variable. The operation is not performed more frequently or suddenly than necessary, and thus a stable refrigeration cycle is obtained.

According to the air conditioner of the fourth aspect of the present invention, when the compressor discharge superheat degree is between the first threshold value and the second threshold value, the heat source side expansion is performed. For controlling the opening of the valve, the opening value determined by the opening adjusting means according to the opening state of the use-side expansion valve is used, so that the supply shortage of the refrigerant to the use-side unit is effectively prevented. As a result, a decrease in heating capacity can be effectively prevented, and as a result, a comfortable air-conditioned space can be realized.

According to the fifth aspect of the present invention, the compressor discharge superheat degree is between the first threshold value and the second threshold value, and at least the use-side expansion valve is When one opening is fully open, to control the opening of the heat source side expansion valve,
Since the opening value determined by adding a certain opening to the current opening is used, the same effect as the air conditioner according to the fourth aspect can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a use-side expansion valve opening / closing control system during a cooling operation in the same embodiment.

FIG. 3 is a characteristic diagram of a membership function used for control during a cooling operation in the embodiment.

FIG. 4 is a block diagram showing a heat source side expansion valve opening / closing control system during heating operation in the same embodiment.

FIG. 5 is a characteristic diagram of a membership function used for control during heating operation in the same embodiment.

FIG. 6 is a characteristic diagram of a membership function used for control in the related art.

[Explanation of symbols]

 10a-10c Air-conditioning space temperature sensor-15a-15c Air-conditioning temperature setting device 20a-20c Use side heat exchanger outlet superheat degree detector 21a-21c Use side superheat degree target setting device 27 Discharge superheat degree detector 28 Discharge superheat degree target setting Units 30a to 30c Cooling operation side expansion valve opening control device 31a Memory content changer 40a to 40c Heating side use expansion valve opening control device 50 Heat source side expansion valve opening control device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Takatani 4-2-5 Takaidahondori, Higashiosaka, Osaka Prefecture Matsushita Refrigerating Machinery Co., Ltd.

Claims (5)

[Claims] 1. A heat source unit having a compressor and a heat source side heat exchanger, one or a plurality of use side units having a use side expansion valve and a use side heat exchanger, and a gas side pipe connecting the both units. , A liquid side pipe, the refrigerant compressed by the compressor, after heat exchange with the outside air in the heat source side heat exchanger, the use side heat exchange through the liquid side pipe and the use side expansion valve A refrigerant circuit is configured to flow into the compressor and exchange heat with the air in the air-conditioned space in which the usage-side unit is installed in the usage-side heat exchanger, and then return to the compressor through the gas-side pipe. In the air conditioner configured as described above, an air-conditioned space temperature detecting means for detecting a temperature of the air-conditioned space, a target temperature setting means for setting a target temperature of the air-conditioned space, and a refrigerant overheat at an outlet of the use side heat exchanger. Use to detect degree Side heat exchanger outlet superheat degree detecting means, target superheat degree setting means for setting a target superheat degree at the outlet of the utilization side heat exchanger of refrigerant, and the air conditioning space temperature detected by the air conditioning space temperature detecting means is the target. First opening degree determining means for determining an opening degree value of the utilization side expansion valve so as to be equal to the temperature set by the temperature setting means, and a superheat degree detected by the utilization side heat exchanger outlet superheat degree detecting means Is calculated the opening change amount of the use side expansion valve so as to be equal to the target superheat degree set by the target superheat degree setting means, the calculated value of the use side expansion valve self-determined during the previous control The second opening degree determining means for determining the opening degree value of the utilization side expansion valve at the time of the next control by adding the opening degree value, and the superheat degree detected by the utilization side heat exchanger outlet superheat degree detecting means are Less than the threshold of 1, and When it is larger than the second threshold value, the opening degree of the utilization side expansion valve is controlled using the opening degree value determined by the second opening degree determining means, and the utilization side heat exchanger outlet superheat degree The degree of superheat detected by the detection means is a third value between the first threshold value and the second threshold value.
Is greater than the threshold value and is less than the fourth threshold value between the third threshold value and the second threshold value,
The opening degree of the utilization side expansion valve is controlled using the opening degree value determined by the opening degree determining means, and the superheat degree detected by the utilization side heat exchanger outlet superheat degree detecting means is the first threshold value. Between the third threshold value and between the fourth threshold value and the second threshold value, based on both opening values determined by the first and second opening determining means, An air conditioner comprising: a control unit that controls the opening degree of the use-side expansion valve using an opening degree value obtained by a membership function having a degree of superheat as a variable. 2. The second opening degree determining means further has a superheat degree detected by the utilization side heat exchanger outlet superheat degree detecting means which is larger than a third threshold value and smaller than a fourth threshold value. During the first control after the state of being in the proper range has been out of the proper range for a certain period of time or longer, the first opening degree is determined in the previous control in place of the self-determined opening degree value of the use-side expansion valve. Using the opening value of the use-side expansion valve determined by the means,
The air conditioner according to claim 1, further comprising an opening degree determining unit that determines an opening degree value of the use-side expansion valve at the time of next control. 3. A heat source unit having a compressor, a heat source side heat exchanger, and a heat source side expansion valve; one or a plurality of use side units having a use side expansion valve and a use side heat exchanger; A gas side pipe and a liquid side pipe to be connected, the refrigerant compressed by the compressor is delivered to the utilization side unit via the gas side pipe, and the delivered refrigerant is the utilization side heat exchange. After heat exchange with the air in the air-conditioned space in which the utilization side unit is arranged in the container, flow into the utilization side heat exchanger via the utilization side expansion valve, the liquid side pipe, the heat source side expansion valve, An air conditioner having a refrigerant circuit configured to recirculate to the compressor after heat exchange with the outside air in the utilization side heat exchanger, compressor discharge superheat detection for detecting the compressor discharge superheat of refrigerant. Means and discharge of said compressor of refrigerant Target superheat degree setting means for setting a target superheat degree in, and the heat source side expansion so that the superheat degree detected by the compressor discharge superheat degree detecting means becomes equal to the superheat degree set by the target superheat degree setting means. The heat source side expansion valve opening degree determining means for determining the valve opening value and the superheat degree detected by the compressor discharge superheat degree detecting means are the first.
When it is smaller than the threshold value of, and when it is larger than the second threshold value, the opening degree of the heat source side expansion valve is set using the opening degree value determined by the heat source side expansion valve opening degree determining means. The superheat degree controlled by the compressor discharge superheat degree detecting means is larger than a third threshold value between the first threshold value and the second threshold value, When it is smaller than the fourth threshold value between the two threshold values, the opening degree of the heat source side expansion valve is controlled so as to maintain the present opening degree value, and the compressor discharge superheat degree detecting means. If the degree of superheat detected by is between the first threshold value and the third threshold value and between the fourth threshold value and the second threshold value, the current opening value And the opening value determined by the heat source side expansion valve opening determining means using the opening value obtained by the membership function with the degree of superheat as a variable. An air conditioning apparatus characterized in that it has a control means for controlling the opening of the heat source side expansion valve, the. 4. An opening state of the use-side expansion valve is detected,
An opening degree adjusting means for determining an opening degree value of the heat source side expansion valve according to the opening degree state is provided, and in the control means, an opening degree value determined by the opening degree adjusting means instead of the current opening degree value. The air conditioner according to claim 3, wherein the air conditioner is used. 5. The heat source by adjusting the opening degree by adding a constant opening degree to the current opening degree of the heat source side expansion valve when at least one opening degree of the utilization side expansion valve is fully opened. The air conditioner according to claim 4, wherein the opening value of the side expansion valve is determined.