JPH1019398A - Multi-chanber type air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the possibility of damaging a compressor due to liquid compression die to liquid return to the compressor and ensure the amount of a refrigerant corresponding to a load in a multi-chamber type or condition err using a non-azeortopic refrigerant. SOLUTION: The present multi-chamber type air conditioner includes a suction pressure sensor 17, an operation frequency detector 25, and a first pressure loss determination means 26 for determining pressure loss in accordance with a detected operation frequency of the operation frequency detector 35. In this case, an outdoor expansion valve 5 is controlled with a difference between detected temperature of the gas piping temperature sensor 18 and saturated temperature at pressure where these is added pressure determined by the first pressure loss determination means 26 to detected pressure by the suction pressure sensor 17 taken as the degree of superheat whereby the degree of superheat is accurately estimated with an inexpensive construction where by liquid compression is prevented and the amount of the refrigerant is ensured corresponding to a load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner using a non-azeotropic mixed refrigerant, and more particularly to control of an outdoor expansion valve.

[0002]

2. Description of the Related Art A conventional multi-chamber air conditioner of this type is disclosed in Japanese Patent Application Laid-Open No. H4-190057.

A conventional multi-room air conditioner disclosed in the above publication will be described below with reference to the drawings.

FIG. 7 is a refrigeration cycle diagram of a conventional multi-room air conditioner. In this figure, reference numeral 1 denotes an outdoor unit of a multi-room air conditioner, which comprises a variable capacity compressor 2, a four-way valve 3, an outdoor heat exchanger 4, and an outdoor expansion valve 5. 6a, 6
b denotes an indoor unit, and indoor expansion valves 7a and 7b, respectively.
It comprises indoor-side heat exchangers 8a and 8b, and is connected to the outdoor unit 1 in parallel by a liquid pipe 9 and a gas pipe 10.

[0005] Reference numeral 11 denotes refrigerant superheat detecting means, which is provided between the outdoor heat exchanger 4 and the variable capacity compressor 2, and detects the refrigerant superheat at that position. Refrigerant superheat detection means 11 for calculating the degree of superheat between the outdoor heat exchanger 4 and the variable capacity compressor 2, and the outdoor expansion valve 5 is operated based on the superheat calculated by the refrigerant superheat detection means 11. There is an outdoor expansion valve operating means 12 to be operated, and these are housed in a control device 13. Regarding the refrigerant superheat detection means 11,
Although not described in detail, a refrigerant gas temperature sensor 14 installed between the outdoor heat exchanger 4 and the variable capacity compressor 2
It is easily anticipated that the value obtained by subtracting the saturation temperature at the detection pressure detected by the second refrigerant pressure sensor 15 from the detection temperature detected by the above is detected as the degree of superheat.

The operation of the multi-room air conditioner configured as described above will be described only for the heating operation, which is a problem.

[0007] The heating operation will be described. The flow of the refrigerant in this case is represented by a practice arrow, and each indoor expansion valve 7 has an opening degree corresponding to each indoor load.

The refrigerant discharged from the compressor 2 is supplied to the four-way valve 3
Through the gas pipe 10, flows into each indoor heat exchanger 8, is condensed and liquefied, and is guided to the liquid pipe 9 through the indoor expansion valve 7. Then, the pressure is reduced to a low-pressure two-phase state by the outdoor expansion valve 5, flows into the outdoor heat exchanger 4, evaporates and returns to the compressor 2 via the four-way valve 3, and performs a heating operation.

At this time, when the degree of superheat increases in accordance with the degree of superheat calculated by the refrigerant superheat degree detecting means 11, the refrigerant is opened.
The outdoor-side expansion valve operating means 12 appropriately controls the opening degree of the outdoor-side expansion valve 5 so as to close when the degree of superheat is reduced, and returns the refrigerant to the compressor 1 as a low-temperature low-pressure gas.

[0010]

However, in the above-mentioned conventional construction, since the detection of the degree of superheat of the refrigerant is detected at a position intermediate between the outdoor heat exchanger and the variable capacity compressor, the true outdoor heat exchanger outlet is detected. In contrast to the degree of superheating, it was difficult to control the amount of the circulating refrigerant to an optimum amount. That is, the refrigerant exchanges heat with the refrigerant pipe and air in the outdoor unit up to the intermediate position between the outdoor heat exchanger and the variable capacity compressor, and detects a value higher than the actual superheat degree of the outdoor heat exchanger outlet, The outdoor expansion valve is opened by the expansion valve operating means. As a result, the refrigerant becomes moist, and as a result, for example, liquid returns to the compressor, leading to liquid compression,
There was a problem that the risk of damaging the compressor was high.

The present invention has been made in view of the above problems, and
Since the degree of superheat at the outdoor unit outlet can be calculated by an inexpensive method, and the outdoor expansion valve can be appropriately controlled, the risk of damaging the compressor due to liquid compression by returning liquid to the compressor can be avoided. Another object of the present invention is to provide a multi-room air conditioner capable of securing a refrigerant amount according to a load.

[0012]

In order to achieve this object, a multi-room air conditioner according to the present invention comprises an outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve; An expansion valve, a plurality of indoor units including an indoor heat exchanger connected in a ring via a gas pipe and a liquid pipe, and a suction pressure sensor for detecting a refrigerant pressure on a suction side of the compressor; and the four-way valve. A gas pipe temperature sensor for detecting a gas refrigerant temperature near the outdoor heat exchanger between the outdoor heat exchanger and a pressure loss between the outdoor heat exchanger and the suction of the compressor; Pressure loss constant determining means, saturation thermometer stage means for calculating a saturated gas temperature of a pressure obtained by adding the pressure determined by the pressure loss constant determining means to the detected pressure of the suction pressure sensor, and detection of the gas pipe temperature sensor Temperature and the saturation temperature calculating means. A superheat degree calculating means for calculating a difference between the calculated saturation temperature and the superheat degree, and an outdoor side which opens when the superheat degree increases and closes when the superheat degree decreases based on the superheat degree calculated by the superheat degree calculation means. An outdoor expansion valve operating means for operating the expansion valve is provided, and a non-azeotropic mixture is used as a refrigerant.

Thus, the degree of superheat at the outlet of the outdoor unit can be calculated by an inexpensive method, and an appropriate outdoor expansion valve can be controlled. Therefore, the compressor is damaged by liquid compression due to liquid return to the compressor. Danger can be avoided, and the amount of refrigerant according to the load can be secured.

A compressor, a four-way valve, an outdoor heat exchanger,
An outdoor unit including an outdoor expansion valve and a plurality of indoor units including an indoor expansion valve and an indoor heat exchanger are connected in a ring via a gas pipe and a liquid pipe, and the refrigerant pressure on the suction side of the compressor is connected. , An operating frequency detector that detects the operating frequency of the compressor, and a gas refrigerant temperature near the outdoor heat exchanger between the four-way valve and the outdoor heat exchanger. A gas pipe temperature sensor, first pressure loss determining means for determining a pressure loss between the outdoor heat exchanger and the suction of the compressor according to a detected operation frequency of the operation frequency detector, and the suction A saturation temperature calculating means for calculating a saturated gas temperature of a pressure obtained by adding the pressure determined by the first pressure loss determining means to the detected pressure of the pressure sensor; and a detection temperature of the gas pipe temperature sensor and the saturation temperature calculating means. Calculated Superheat degree calculating means for calculating the difference from the saturation temperature as the degree of superheat, and an outdoor expansion valve to be opened when the degree of superheat is increased and closed when the degree of superheat is reduced based on the degree of superheat calculated by the degree of superheat calculation means. An outdoor expansion valve operating means for operating is provided, and a non-azeotropic mixture is used as a refrigerant.

Thus, the degree of superheat at the outdoor unit outlet can be accurately calculated by an inexpensive method, and the outdoor expansion valve can be appropriately controlled. The risk of breakage can be avoided, and the amount of refrigerant according to the load can be secured.

Further, an outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve, and a plurality of indoor units comprising an indoor expansion valve and an indoor heat exchanger are connected to a gas pipe and a liquid pipe. A suction pressure sensor that detects a refrigerant pressure on the suction side of the compressor, an operation frequency detector that detects an operation frequency of the compressor, the four-way valve, and the outdoor heat exchanger A gas pipe temperature sensor for detecting a gas refrigerant temperature near the outdoor heat exchanger between the outdoor heat exchanger, and the outdoor heat exchanger according to a detection operation frequency of the operation frequency detector and a detection pressure of the suction pressure sensor. And a second pressure loss determining means for determining a pressure loss during suction of the compressor, and a pressure saturation obtained by adding a pressure determined by the second pressure loss determining means to a detected pressure of the suction pressure sensor. Saturation to calculate gas temperature Degree calculation means, superheat degree calculation means for calculating the difference between the detected temperature of the gas pipe temperature sensor and the saturation temperature calculated by the saturation temperature calculation means as the degree of superheat, and the degree of superheat calculated by the degree of superheat calculation means An outdoor expansion valve operating means for operating an outdoor expansion valve to open when the degree of superheat is large and close when the degree of superheat is small is provided, and a non-azeotropic mixture tail is used as a refrigerant.

Thus, the degree of superheat at the outlet of the outdoor unit can be calculated more accurately by an inexpensive method, and the outdoor expansion valve can be appropriately controlled. Avoid the risk of damage,
The amount of refrigerant according to the load can be secured.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger and an outdoor expansion valve, an indoor expansion valve and an indoor heat exchange. A plurality of indoor units consisting of a unit is connected in a ring via a gas pipe and a liquid pipe, a suction pressure sensor for detecting a refrigerant pressure on a suction side of the compressor, the four-way valve and the outdoor heat exchanger, A gas pipe temperature sensor for detecting a gas refrigerant temperature near the outdoor heat exchanger, and a pressure loss constant determining means for determining a pressure loss between the outdoor heat exchanger and the suction of the compressor, Saturation temperature calculation means for calculating a saturated gas temperature of a pressure obtained by adding the pressure determined by the pressure loss constant determination means to the detection pressure of the suction pressure sensor, and the detection temperature of the gas pipe temperature sensor and the saturation temperature calculation means With the calculated saturation temperature A superheat degree calculating means for calculating the superheat degree as the superheat degree, and an outdoor expansion valve for operating the outdoor expansion valve so as to open when the superheat degree increases and close when the superheat degree decreases based on the superheat degree calculated by the superheat degree calculation means. A valve operating means is provided, and a non-azeotropic mixture is used as a refrigerant. The superheat degree at the outlet of the outdoor unit can be calculated by an inexpensive method.

According to a second aspect of the present invention, there is provided an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve.
A plurality of indoor units including an indoor expansion valve and an indoor heat exchanger connected in a ring through a gas pipe and a liquid pipe, and a suction pressure sensor for detecting a refrigerant pressure on a suction side of the compressor; An operating frequency detector that detects an operating frequency of the machine, a gas pipe temperature sensor that detects a gas refrigerant temperature near the outdoor heat exchanger between the four-way valve and the outdoor heat exchanger, and the operating frequency First pressure loss determining means for determining a pressure loss between the outdoor heat exchanger and the suction of the compressor according to a detection operation frequency of a detector; and Saturation temperature calculation means for calculating a saturated gas temperature of the pressure obtained by adding the pressure determined by the pressure loss determination means, and heating the difference between the detected temperature of the gas pipe temperature sensor and the saturation temperature calculated by the saturation temperature calculation means. As a degree Superheat degree calculating means for calculating, and an outdoor expansion valve operating means for operating an outdoor expansion valve to open when the superheat degree increases and close when the superheat degree decreases based on the superheat degree calculated by the superheat degree calculation means. Provided,
Since the pressure loss between the outdoor heat exchanger and the suction of the compressor is predicted based on the operating frequency, the degree of superheat at the outdoor unit outlet can be accurately determined using an inexpensive method. Can be calculated.

According to a third aspect of the present invention, there is provided an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve.
A plurality of indoor units including an indoor expansion valve and an indoor heat exchanger connected in a ring through a gas pipe and a liquid pipe, and a suction pressure sensor for detecting a refrigerant pressure on a suction side of the compressor; An operating frequency detector that detects an operating frequency of the machine, a gas pipe temperature sensor that detects a gas refrigerant temperature near the outdoor heat exchanger between the four-way valve and the outdoor heat exchanger, and the operating frequency The second determining the pressure loss between the outdoor heat exchanger and the suction of the compressor according to the detection operation frequency of the detector and the detection pressure of the suction pressure sensor.
Pressure loss determination means, and saturation temperature calculation means for calculating a saturated gas temperature of a pressure obtained by adding the pressure determined by the second pressure loss determination means to the detected pressure of the suction pressure sensor,
Superheat degree calculation means for calculating the difference between the detected temperature of the gas pipe temperature sensor and the saturation temperature calculated by the saturation temperature calculation means as superheat degree, and the degree of superheat calculated based on the degree of superheat calculated by the superheat degree calculation means An outdoor expansion valve operating means for operating an outdoor expansion valve to open when it becomes large and close when the degree of superheat becomes small is provided, and a non-azeotropic mixture is used as a refrigerant. Since the pressure loss between the outdoor heat exchanger and the suction of the compressor is predicted, the degree of superheat at the outdoor unit outlet can be calculated more accurately by an inexpensive method.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. Note that the same components as those of the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Embodiment 1) FIG. 1 shows a refrigerant cycle diagram of a multi-room air conditioner using a non-azeotropic mixed refrigerant.
, 16 is an outdoor unit of a multi-room air conditioner,
Reference numeral 7 denotes a suction pressure sensor provided on a suction pipe of the variable capacity compressor 2, and reference numeral 18 denotes a gas pipe temperature for detecting a gas refrigerant temperature near the outdoor heat exchanger 4 between the outdoor heat exchanger 4 and the four-way valve 3. A sensor 19 for determining a pressure loss constant based on a pipe diameter and a pipe length between the outdoor heat exchanger 4 and the suction of the compressor 2;
Saturation temperature calculating means for calculating the saturated gas temperature of the pressure obtained by adding the pressure determined by the pressure loss constant determining means 19 to the detected pressure of the above, and the detection temperature of the gas pipe temperature sensor 18 and the saturation temperature calculation means 21 were calculated. Superheat degree calculating means 22 for calculating the difference from the saturation temperature as the degree of superheat is an outdoor expansion valve which is opened based on the degree of superheat calculated by the superheat degree calculating means 21 and is closed when the degree of superheat becomes small and closed when the degree of superheat becomes small. 5 are operating means for operating the outdoor expansion valve, which are housed in the control device 23.

(Embodiment 2) FIG. 3 shows a refrigerant cycle diagram of a multi-room air conditioner using a non-azeotropic mixed refrigerant.
, 24 is an outdoor unit of a multi-room air conditioner,
Reference numeral 7 denotes a suction pressure sensor provided in a suction pipe of the variable capacity compressor 2, 25 denotes an operation frequency detector for detecting an operation frequency of the variable capacity compressor 2, and 18 denotes a connection between the outdoor heat exchanger 4 and the four-way valve 3. A gas pipe temperature sensor for detecting the temperature of the gas refrigerant near the outdoor heat exchanger 4 between the two, and 26 is an operating frequency detector 2
A first pressure loss determining means for determining a pressure loss between the outdoor heat exchanger 4 and the suction of the compressor 2 in accordance with the detection operation frequency of 5; Saturation temperature calculating means 21 for calculating a saturated gas temperature at a pressure obtained by adding the pressure determined by the loss determining means 25, and a detection temperature 21 of the gas pipe temperature sensor 18 and a saturation temperature calculating means
The superheat degree calculating means 22 for calculating the difference between the superheat degree and the saturation temperature calculated as the superheat degree opens based on the superheat degree calculated by the superheat degree calculation means 21 when the superheat degree increases and closes when the superheat degree decreases. Outdoor expansion valve operating means for operating the outdoor expansion valve 5, which are housed in the control device 27.

(Embodiment 3) FIG. 5 shows a refrigerant cycle diagram of a multi-room air conditioner using a non-azeotropic mixed refrigerant.
And 28, an outdoor unit of a multi-room air conditioner,
Reference numeral 7 denotes a suction pressure sensor provided on a suction pipe of the variable capacity compressor 2, 24 denotes an operation frequency detector for detecting an operation frequency of the variable capacity compressor 2, and 18 denotes a connection between the outdoor heat exchanger 4 and the four-way valve 3. A gas pipe temperature sensor for detecting the temperature of the gas refrigerant in the vicinity of the outdoor heat exchanger 4 between the two;
A second pressure loss determining means for determining a pressure loss between the outdoor heat exchanger 4 and the suction of the compressor 2 according to the detected operation frequency of the suction pressure sensor 4 and the pressure detected by the suction pressure sensor 17; Pressure loss determining means 2
A saturation temperature calculating means for calculating a saturated gas temperature at a pressure obtained by adding the pressure determined in step 9;
The superheat degree calculating means 22 for calculating the difference between the detected temperature and the saturation temperature calculated by the saturation temperature calculation means 20 as the superheat degree is opened when the superheat degree increases based on the superheat degree calculated by the superheat degree calculation means 21. Outdoor expansion valve operating means for operating the outdoor expansion valve 5 so as to close when the degree of superheat is reduced, and these are housed in the control device 30.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the multi-room air conditioner constructed as described above will be described with respect to a heating operation which is a problem here. Note that the detailed description of the same operation as that in the related art is omitted.

Embodiment 1 FIG. 2 shows Embodiment 1 of the present invention.
3 is a flowchart of the multi-room air conditioner in FIG.

As shown in FIG. 2, when the controller 23 detects a heating operation command in STEP 1, the gas pipe temperature sensor 18 detects the temperature To of the gas side pipe To of the outdoor heat exchanger 4 in STEP 2.
And the suction pressure sensor 17 detects the pressure Ps on the suction side of the variable capacity compressor 2. In STEP 3, a pressure loss constant determined in advance based on a pipe diameter and a pipe length between the outdoor heat exchanger 4 and the suction of the compressor 2 is determined. In STEP4, the pressure detected in STEP2 is
Based on the pressure obtained by adding the pressure loss constant determined in EP3,
The saturated gas temperature Teo at the outlet of the outdoor heat exchanger 4 is calculated by the saturated temperature calculating means 20. In STEP5, the superheat degree calculating means 21 detects the gas pipe temperature To detected in STEP2 and the saturated gas temperature Teo calculated in STEP4.
And the superheat degree SH = To−Teo is calculated from
Then, according to the superheat degree SH calculated in STEP5, the outdoor expansion valve 5 is operated so as to open when the superheat degree increases and close when the superheat degree decreases.

According to the first embodiment, since the pressure loss constant is determined by the pipe diameter and the pipe length between the outdoor heat exchanger 4 and the suction of the compressor 2, etc., the outdoor unit outlet can be inexpensively manufactured. The degree of superheat can be calculated, and the outdoor expansion valve can be appropriately controlled, so that the risk of damage to the compressor due to liquid compression due to liquid return to the compressor can be avoided, and the amount of refrigerant according to the load can be reduced. Can be secured.

As the non-azeotropic refrigerant mixture, for example, HF
It is a C-based mixed refrigerant. R32 / 125 / 134a (3
0/10 / 60wt%) or R32 / 125 / 134a
It goes without saying that (23/25/52 wt%) can be used. The present invention is also applicable to an air conditioner having one indoor unit and one outdoor unit, and a multi-room air conditioner having a plurality of indoor units and a plurality of outdoor units.

(Embodiment 2) FIG. 4 shows Embodiment 2 of the present invention.
3 is a flowchart of the multi-room air conditioner in FIG.

Referring to FIG. 4, when the control device 27 detects a heating operation command in STEP 1, the gas pipe temperature sensor 18 detects the temperature To of the gas side pipe To of the outdoor heat exchanger 4 in STEP 2.
The operating frequency detector 25 detects the operating frequency of the variable capacity compressor 2, and the suction pressure sensor 17 detects the pressure Ps on the suction side of the variable capacity compressor 2. In STEP 3, the first pressure loss that determines the pressure loss between the outdoor heat exchanger 4 and the suction of the compressor 2 according to the operation frequency detected by the operation frequency detector 25 is determined. In STEP4, ST
Based on the pressure obtained by adding the first pressure loss determined in STEP 3 to the pressure detected in EP 2, the saturated gas temperature Teo at the outlet of the outdoor heat exchanger 4 is calculated by the saturation temperature calculating means 20. At STEP5, the gas pipe temperature To detected at STEP2 by the superheat degree calculating means 21 is compared with STEP4.
Superheat degree SH = To from the saturated gas temperature Teo calculated in
-Teo is calculated, and in STEP6, in accordance with the superheat degree SH calculated in STEP5, the outdoor expansion valve 5 is opened so as to open when the superheat degree increases and close when the superheat degree decreases.
To work.

According to the second embodiment, since the pressure loss between the outdoor heat exchanger 4 and the suction of the compressor 2 according to the detected operation frequency is determined, the degree of superheat at the outdoor unit outlet can be reduced by an inexpensive method. Can be accurately calculated, and the outdoor expansion valve can be appropriately controlled, so that the risk of damage to the compressor due to liquid compression due to liquid return to the compressor can be avoided, and the amount of refrigerant corresponding to the load can be reduced. Can be secured.

As the non-azeotropic refrigerant mixture, for example, HF
R32 / 125 / 134a (3
0/10 / 60wt%) or R32 / 125 / 134a
It goes without saying that (23/25/52 wt%) can be used. The present invention is also applicable to an air conditioner having one indoor unit and one outdoor unit, and a multi-room air conditioner having a plurality of indoor units and a plurality of outdoor units.

(Embodiment 3) FIG. 6 shows Embodiment 2 of the present invention.
3 is a flowchart of the multi-room air conditioner in FIG.

As shown in FIG. 6, when the control device 30 detects a heating operation command in STEP1, the gas pipe temperature sensor 18 detects the temperature To of the gas pipe of the outdoor heat exchanger 4 in STEP2.
The operating frequency detector 25 detects the operating frequency of the variable capacity compressor 2, and the suction pressure sensor 17 detects the pressure Ps on the suction side of the variable capacity compressor 2. In STEP 3, a second pressure loss that determines a pressure loss between the outdoor heat exchanger 4 and the suction of the compressor 2 according to the detection operation frequency of the operation frequency detector 25 and the detection pressure of the suction pressure sensor 17 is determined. I do. In STEP4, the saturated gas temperature Teo at the outlet of the outdoor heat exchanger 4 is calculated by the saturation temperature calculating means 20 based on the pressure obtained by adding the second pressure loss determined in STEP3 to the pressure detected in STEP2. STEP
In 5, the superheat degree SH = To−Teo is calculated from the gas pipe temperature To detected in STEP2 by the superheat degree calculation means 21 and the saturation gas temperature Teo calculated in STEP4.
In STEP6, the outdoor expansion valve 5 is operated to open when the degree of superheat increases and close when the degree of superheat decreases, in accordance with the degree of superheat SH calculated in STEP5.

According to the third embodiment, the pressure loss between the outdoor heat exchanger 4 and the suction of the compressor 2 according to the operating frequency and the suction pressure is determined. The degree of superheat can be calculated more accurately, and the outdoor expansion valve can be appropriately controlled, so that the risk of damaging the compressor due to liquid compression by returning liquid to the compressor can be avoided, and the load can be adjusted according to the load. Refrigerant amount can be secured.

As the non-azeotropic mixed refrigerant, for example, HF
R32 / 125 / 134a (3
0/10 / 60wt%) or R32 / 125 / 134a
It goes without saying that (23/25/52 wt%) can be used. The present invention is also applicable to an air conditioner having one indoor unit and one outdoor unit, and a multi-room air conditioner having a plurality of indoor units and a plurality of outdoor units.

[0038]

As described above, according to the present invention, the degree of superheat at the outlet of the outdoor unit can be calculated by an inexpensive method, and the outdoor expansion valve can be appropriately controlled. By the liquid compression, the risk of damaging the compressor can be avoided, and the amount of refrigerant according to the load can be secured.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of a multi-room air conditioner according to a first embodiment of the present invention.

FIG. 2 is a block diagram of the multi-room air conditioner of the embodiment.

FIG. 3 is a control flowchart of an outdoor expansion valve of the multi-room air conditioner of the embodiment.

FIG. 4 is a refrigeration cycle diagram of a multi-room air conditioner according to a second embodiment of the present invention.

FIG. 5 is a block diagram of the multi-room air conditioner of the embodiment.

FIG. 6 is a control flowchart of an outdoor expansion valve of the multi-room air conditioner of the embodiment.

FIG. 7 is a refrigeration cycle diagram of a conventional multi-room air conditioner.

[Explanation of symbols]

 2 Compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Outdoor expansion valve 6 Indoor unit 7 Indoor expansion valve 8 Indoor heat exchanger 9 Liquid pipe 10 Gas pipe 16 Outdoor unit 17 Suction pressure sensor 18 Gas pipe temperature sensor 19 Pressure loss constant determining means 20 Saturation temperature calculating means 21 Superheat degree calculating means 22 Outdoor expansion valve operating means 23 Controller

 ──────────────────────────────────────────────────の Continuing on the front page (72) Kazuo Nakatani, Kazuma, Kazuma, Osaka 1006, Kadoma, Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] An outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and a plurality of indoor units comprising an indoor expansion valve and an indoor heat exchanger are connected to a gas pipe and a liquid pipe. A ring-shaped connection via a suction pressure sensor for detecting the refrigerant pressure on the suction side of the compressor and the gas refrigerant temperature near the outdoor heat exchanger between the four-way valve and the outdoor heat exchanger. A gas pipe temperature sensor for detecting, a pressure loss constant determining means for determining a pressure loss between the outdoor heat exchanger and the suction of the compressor, and a pressure loss constant determining means for detecting a pressure of the suction pressure sensor. A saturated temperature calculating means for calculating a saturated gas temperature at a pressure to which the determined pressure is applied; and superheating for calculating a difference between a detected temperature of the gas pipe temperature sensor and a saturated temperature calculated by the saturated temperature calculating means as a degree of superheating. Degree calculation means and before An outdoor expansion valve operating means for operating an outdoor expansion valve to open when the degree of superheat is increased and close when the degree of superheat is reduced based on the degree of superheat calculated by the degree of superheat calculated by the degree of superheat is provided, and the non-azeotropic mixture is used as a refrigerant. Multi-room air conditioner using. 2. A gas pipe and a liquid pipe including an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and a plurality of indoor units including an indoor expansion valve and an indoor heat exchanger. A suction pressure sensor that detects a refrigerant pressure on the suction side of the compressor, an operation frequency detector that detects an operation frequency of the compressor, the four-way valve, and the outdoor heat exchanger A gas pipe temperature sensor for detecting a gas refrigerant temperature in the vicinity of the outdoor heat exchanger between the outdoor heat exchanger and the suction of the compressor according to the detected operating frequency of the operating frequency detector. Pressure loss determining means for determining the pressure loss of the suction pressure sensor, the first pressure loss loss determining means for the pressure detected by the suction pressure sensor, and the first pressure loss determining means for the pressure detected by the suction pressure sensor Saturation of pressure plus pressure determined in Saturation temperature calculation means for calculating gas temperature, superheat degree calculation means for calculating the difference between the detected temperature of the gas pipe temperature sensor and the saturation temperature calculated by the saturation temperature calculation means as superheat degree, and the superheat degree calculation An outdoor expansion valve operating means for operating an outdoor expansion valve to open when the degree of superheat increases and close when the degree of superheat decreases when the degree of superheat increases based on the degree of superheat calculated by the means is provided. Room type air conditioner. 3. A gas pipe and a liquid pipe including an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and a plurality of indoor units including an indoor expansion valve and an indoor heat exchanger. A suction pressure sensor that detects a refrigerant pressure on the suction side of the compressor, an operation frequency detector that detects an operation frequency of the compressor, the four-way valve, and the outdoor heat exchanger A gas pipe temperature sensor for detecting a gas refrigerant temperature near the outdoor heat exchanger between the outdoor heat exchanger, and the outdoor heat exchanger according to a detection operation frequency of the operation frequency detector and a detection pressure of the suction pressure sensor. And a second pressure loss determining means for determining a pressure loss during suction of the compressor, and a pressure saturation obtained by adding a pressure determined by the second pressure loss determining means to a detected pressure of the suction pressure sensor. Saturation temperature calculation to calculate gas temperature Means, superheat degree calculation means for calculating the difference between the detected temperature of the gas pipe temperature sensor and the saturation temperature calculated by the saturation temperature calculation means as superheat degree, and based on the degree of superheat calculated by the superheat degree calculation means A multi-chamber air conditioner comprising an outdoor expansion valve operating means for operating an outdoor expansion valve to open when the degree of superheat increases and close when the degree of superheat decreases, and using a non-azeotropic mixture as a refrigerant.