JPH0611205A - Air conditioning apparatus - Google Patents

Abstract

PURPOSE:To obtain an air conditioning apparatus where gas injection can be used without spoiling the reliability of a compressor even when the outdoor load fluctuates during air conditioning operation. CONSTITUTION:An air conditioning apparatus is provided with an outside temperature detector 21 which detects the outside temperatures, an intermediate pressure detector 22 which detects the intermediate pressure of a gas-liquid separator 14, an air conditioning mode judging device 24 which judges cooling or heating operation mode, a set intermediate pressure arithmetic device 25 which does arithmetic of set intermediate pressure based on the outside temperatures. In addition, an intermediate pressure judging device 26 which compares the arithmetic result with the intermediate pressure to judge, a pressure reducing amount decision device 27 which decides the pressure reducing amount of a pressure reducing device 15 for air conditioning corresponding to the judgment result, and a pressure reducing device driver 28 which drives the pressure reducing device 15 for air conditioning corresponding to the pressure reducing amount are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of a heating and cooling system equipped with gas injection.

[0002]

2. Description of the Related Art As a conventional technique, JP-A-57-124 is known.
There is an air conditioner as disclosed in Japanese Patent No. 661.

A conventional technique will be described below with reference to the drawings. In FIG. 5, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is a first pressure reducing device made of a capillary, 5 is a gas-liquid separator, 6 is a second pressure reducing device made of a capillary, 7 Is an indoor heat exchanger, 8 is an accumulator,
These are communicated via the refrigerant pipe 9 to form a refrigerant cycle.

An on-off valve 10 is provided on an injection pipe 11 which connects the compressor 1 and the upper portion of the gas-liquid separator 5 to each other.

The operation of the air conditioner configured as above will be described. First, during the cooling operation, the refrigerant cycle indicated by the solid arrow in FIG. 5 is performed, and the high-temperature high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 and radiates heat in the outdoor heat exchanger 3 to be condensed and liquefied. Intermediate pressure at 4 (about 1MP
It is depressurized to a) and sent to the gas-liquid separator 5.

The refrigerant discharged from the gas-liquid separator 5 is decompressed by the second decompression device 6, endothermicly evaporated by the indoor heat exchanger 7 and circulated to the compressor 1 through the four-way valve 2 and the accumulator 8.

At this time, when the on-off valve 10 is opened, the gas refrigerant from the gas-liquid separator 5 is guided to the compressor 1 through the injection pipe 11, so that the liquid refrigerant having a small enthalpy flows to the indoor heat exchanger 7, Cooling capacity increases.

On the other hand, during the heating operation, the refrigerant cycle indicated by the broken line arrow in FIG. 5 is performed, and the high-temperature high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 and radiates heat in the indoor heat exchanger 7 to be condensed and liquefied. The pressure is reduced to an intermediate pressure (about 0.6 MPa) by the two pressure reducing devices 6 and sent to the gas-liquid separator 5.

The refrigerant discharged from the gas-liquid separator 5 is decompressed by the first decompression device 4, endothermicly evaporated by the outdoor heat exchanger 3 and circulated to the compressor 1 through the four-way valve 2 and the accumulator 8.

At this time, when the on-off valve 10 is opened, the gas refrigerant from the gas-liquid separator 5 is guided to the compressor 1 through the injection pipe 11, so that the refrigerant flowing in the indoor heat exchanger 7 by the amount of this gas refrigerant. The amount increases and the heating capacity increases.

[0011]

However, in the above-mentioned configuration, the decompression amounts of the first decompression device 4 and the second decompression device 6 are constant, although the proper intermediate pressures differ during the heating and cooling operation. When gas injection is used in both the heating and cooling operation, the liquid refrigerant flows into the compressor 1 through the injection pipe 11 during either operation,
There is a problem that the reliability of the compressor 1 is impaired.

Further, since the pressure reducing amounts of the first pressure reducing device 4 and the second pressure reducing device 6 are constant, the liquid refrigerant is injected into the injection pipe 1 even when the outdoor load changes and the refrigerant circulation amount changes.
There is a problem that the reliability of the compressor 1 is impaired by flowing through the compressor 1 into the compressor 1.

The present invention solves the above-mentioned problems. The gas injection can be used without impairing the reliability of the compressor and the cooling and heating capacity can be increased during both the heating and cooling operations and also when the outdoor load changes. The purpose is to provide an air conditioner.

[0014]

In order to achieve this object, an air conditioner according to the present invention comprises a pressure reducing device for cooling, a check valve for cooling, a gas-liquid separator, and a pressure reducing device for both heating and cooling of which the amount of pressure reduction is variable. Check valve for heating and a pressure reducing device for heating, which are located in parallel with the pressure reducing device for cooling and the check valve for cooling, an injection pipe having an on-off valve for connecting the gas-liquid separator and the compressor, and detecting the outside air temperature. Outside air temperature detecting means, intermediate pressure detecting means for detecting the pressure of the gas-liquid separator, cooling / heating mode determining means for determining cooling or heating, and set value of the intermediate pressure based on the outside air temperature detected by the outside air temperature detecting means. The intermediate pressure determining means for comparing the calculated result with the pressure detected by the intermediate pressure detecting means, and the decompression amount of the heating / cooling decompressor according to the determination result. Decompression amount judgment And means, has a configuration including a pressure reducing device driving means for driving the cooling and heating combined decompressor in response to the pressure reduction amount.

[0015]

According to the present invention, when the cooling / heating mode determining means determines the cooling operation, the intermediate pressure suitable for the cooling operation is set based on the outside air temperature detected by the outside air temperature detecting means. Calculated by the means, the result and the pressure detected by the intermediate pressure detecting means are compared and determined by the intermediate pressure determining means, and the pressure reducing amount is determined by the pressure reducing amount determining means according to the result,
The decompression device driving means drives the cooling / heating decompression device.

When the cooling / heating mode determining means determines that the heating operation is performed, the intermediate pressure suitable for the heating operation is calculated by the set intermediate pressure calculating means based on the outside air temperature detected by the outside air temperature detecting means. The pressure detected by the intermediate pressure detection means is compared and determined by the intermediate pressure determination means, the reduced pressure amount determination means determines the reduced pressure amount according to the result, and the pressure reduction device driving means drives the cooling / heating combined pressure reduction device.

As a result, the intermediate pressure is maintained at an appropriate value even when the outdoor load fluctuates during both heating and cooling operations, and the inflow of liquid refrigerant from the injection pipe to the compressor is prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a refrigerant cycle diagram of the cooling / heating device according to the present embodiment, FIG. 2 is a control flowchart of the heating / cooling decompression device, FIG. 3 is a characteristic diagram showing the correlation between the set intermediate pressure and the outside air temperature during the cooling operation, and FIG. 4 is the heating operation. FIG. 7 is a characteristic diagram showing a correlation between a set intermediate pressure and an outside air temperature at the time. It should be noted that the same components as those of the related art are designated by the same reference numerals and detailed description thereof will be omitted.

In FIG. 1, reference numeral 12 is a decompression device for cooling, which has a pressure of about 1 M when operated under JIS cooling standard conditions.
A capillary tube that can reduce the pressure to Pa is used. Reference numeral 13 is a check valve for cooling. 14 is a gas-liquid separator. Reference numeral 15 is a cooling / heating decompression device, which uses an electric expansion valve. Reference numeral 16 denotes an indoor heat exchanger, which is housed in the indoor unit f.

Compressor 1, four-way valve 2, outdoor heat exchanger 3,
Cooling decompression device 12, cooling check valve 13, gas-liquid separator 1
4 lower part, cooling / heating decompression device 15, indoor heat exchanger 1
6, the accumulator 8 is connected via the refrigerant pipe 18 to form a refrigerant cycle.

Reference numeral 19 is a check valve for heating. Reference numeral 20 denotes a heating decompression device, which uses a capillary tube. The check valve 19 for heating and the pressure reducing device 20 for heating are installed in parallel with the pressure reducing device 12 for cooling and the check valve 13 for cooling.

Reference numeral 21 is an outside air temperature detecting means, which is an outdoor unit g.
A thermistor is attached to. Reference numeral 22 is an intermediate pressure detecting means, and a pressure sensor is attached to the gas-liquid separator 14. Reference numeral 23 is a remote controller for the indoor unit f.

Reference numeral 24 is a cooling / heating mode determining means, which determines whether the operation is the cooling operation or the heating operation according to a signal from the remote controller 23. Reference numeral 25 denotes a set intermediate pressure calculating means, which determines a set intermediate pressure suitable for cooling / heating operation based on the outside air temperature detected by the outside air temperature detecting means 21. Reference numeral 26 denotes an intermediate pressure determining means, which determines whether the pressure detected by the intermediate pressure detecting means 22 is higher or lower than the set intermediate pressure. Reference numeral 27 denotes a decompression amount determination means, which determines how much (for example, 20 pulses) the electric expansion valve 15 is opened or throttled according to the determination result of the intermediate pressure determination means 26. Decompression device driving means 28 transmits the number of pulses corresponding to the determination result of the decompression amount determination means 27 to the electric expansion valve 15 to drive it.

Reference numeral 29 is a control device, which comprises a cooling / heating mode determination means 24, a set intermediate pressure calculation means 25, an intermediate pressure determination means 26, a reduced pressure amount determination means 27, and a reduced pressure device drive means 28.

The operation of the cooling and heating apparatus configured as described above will be described. First, during the cooling operation, the refrigerant cycle indicated by the solid arrow in FIG. 1 is performed, and the high-temperature high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 to radiate heat in the outdoor heat exchanger 3 to be condensed and liquefied, and the decompression device for cooling. The pressure is reduced at 12 and is sent to the gas-liquid separator 14 through the cooling check valve 13. And
The pressure in the gas-liquid separator 14 is adjusted by the electric expansion valve 15 so that it becomes a set intermediate pressure, and the heat is evaporated and absorbed in the indoor heat exchanger 16 to circulate to the compressor 1 through the four-way valve 2 and the accumulator 8. .

At this time, when the opening / closing valve 10 is opened, the gas refrigerant is guided from the gas-liquid separator 14 to the compressor 1 through the injection pipe 11.

On the other hand, during the heating operation, the refrigerant cycle indicated by the broken line arrow in FIG. 1 is performed, and the high-temperature high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 and radiates heat in the indoor heat exchanger 16 to be condensed and liquefied, which is electrically driven. The expansion valve 15 adjusts the pressure in the gas-liquid separator 14 so as to reach the set intermediate pressure. And gas-liquid separator 1
The refrigerant discharged from 4 is decompressed by the heating decompression device 20, passes through the heating check valve 19 and is endothermicly evaporated by the outdoor heat exchanger 3, and circulates to the compressor 1 through the four-way valve 2 and the accumulator 8.

At this time, when the opening / closing valve 10 is opened, the gas refrigerant is guided from the gas-liquid separator 14 to the compressor 1 through the injection pipe 11.

Next, the control of the electric expansion valve 15 will be described with reference to FIG.
Will be explained. Step 1 is the outside temperature detecting means 21.
Then, the outside air temperature Ao is detected by the thermistor, and the routine proceeds to step 2. Step 2 is the intermediate pressure detecting means 22, which detects the intermediate pressure Pm of the gas-liquid separator 14 with the pressure sensor and shifts to step 3. Step 3 is the cooling / heating mode determination means 24, which determines from the signal from the remote controller 23 whether cooling or heating, and when cooling is in progress, the process proceeds to step 4.

Step 4 is the set intermediate pressure calculating means 25, which calculates the set intermediate pressure Pcm during cooling using the equation Pcm = a × Ao + b, and shifts to step 5. In this equation, it is known from the experiments by the inventors that the proper set intermediate pressure Pcm and the outside air temperature Ao have a correlation as shown in FIG. 3, and the constant a = 0.023,
b = 0.2.

Step 5 is the intermediate pressure determination means 26, and when the intermediate pressure Pm and the set intermediate pressure Pcm are equal, it is determined that the intermediate pressure Pm is appropriate and the process returns to step 1 to set the intermediate pressure Pm and the set intermediate pressure Pcm. When is not equal, the process proceeds to step 6. Step 6 is also the intermediate pressure determination means 26, and when it is determined that the intermediate pressure Pm is larger than the set intermediate pressure Pcm, the process proceeds to step 7.

Step 7 is the decompression amount determination means 27,
In order to reduce the intermediate pressure Pm, the opening degree of the electric expansion valve 15 is determined to be "20 pulse open", and the process proceeds to step 9.
In step 9, the pressure reducing device driving means 28 transmits a pulse signal to the electric expansion valve 15, opens 20 pulses, and returns to step 1.

When it is determined in step 6 that the intermediate pressure Pm is lower than the set intermediate pressure Pcm, the process proceeds to step 8. Step 8 is the decompression amount determination means 27, and the opening degree of the electric expansion valve 15 is set to "20" in order to increase the intermediate pressure Pm.
It is determined that the pulse is closed, and the process proceeds to step 9. Step 9 is the pressure reducing device driving means 28, which transmits a pulse signal to the electric expansion valve 15 to throttle it by 20 pulses, and then returns to step 1.

When the heating operation is determined in step 3,
Go to step 10. Step 10 is the set intermediate pressure calculating means 25, which calculates the set intermediate pressure Phm during heating using the equation Phm = c × Ao + d and shifts to step 11. In this equation, it is known from the experiments by the inventors that the appropriate set intermediate pressure Phm and the outside air temperature Ao have a correlation as shown in FIG. 4, and the constant c = 0.02 from FIG.
d = 0.5.

Step 11 is the intermediate pressure judging means 26, and when the intermediate pressure Pm and the set intermediate pressure Phm are equal, it is judged that the intermediate pressure Pm is appropriate and the process returns to step 1 to set the intermediate pressure Pm and the set intermediate pressure Phm. When is not equal, the process proceeds to step 12. Step 12 is also the intermediate pressure determination means 26, and the intermediate pressure Pm is the set intermediate pressure Ph.
When it is determined that it is larger than m, the process proceeds to step 13.

Step 13 is the depressurization amount determination means 27, which determines that the opening degree of the electric expansion valve 15 is "20 pulse closed" in order to reduce the intermediate pressure Pm, and shifts to step 9. Step 9 is the pressure reducing device driving means 28, which transmits a pulse signal to the electric expansion valve 15 to throttle it by 20 pulses, and then returns to step 1.

When it is determined in step 12 that the intermediate pressure Pm is lower than the set intermediate pressure Phm, the process proceeds to step 14. Step 14 is the decompression amount determination means 27, which determines that the opening degree of the electric expansion valve 15 is "20 pulse open" in order to increase the intermediate pressure Pm, and proceeds to step 9. Step 9 is the pressure reducing device driving means 28, which transmits a pulse signal to the electric expansion valve 15 to open 20 pulses,
Return to.

According to the above embodiment, since the intermediate pressure Pm is always adjusted to an appropriate value, the liquid refrigerant flows from the injection pipe 11 into the compressor 1 during both heating and cooling operations and also when the outdoor load changes. This can be prevented, and the cooling and heating capacity can be increased without impairing the reliability of the compressor 1.

[0039]

As is apparent from the above description, the present invention includes a cooling decompression device, a cooling check valve, a gas-liquid separator, and a cooling / heating decompression device with variable decompression amount. A check valve for heating and a pressure reducing device for heating, which are located in parallel with the check valve for cooling, an injection pipe having an on-off valve for communicating the gas-liquid separator and the compressor, and an outside air temperature detecting means for detecting the outside air temperature. An intermediate pressure detection means for detecting the pressure of the gas-liquid separator, a cooling / heating mode determination means for determining cooling or heating, and an intermediate pressure set value based on the outside air temperature detected by the outside air temperature detection means according to cooling / heating. Set intermediate pressure calculating means for calculating the intermediate pressure determination means for comparing the calculated result with the pressure detected by the intermediate pressure detecting means, and a pressure reducing method for determining the pressure reduction amount of the cooling / heating decompression device according to the determination result. Volume determination means and this decompression By providing the pressure reducing device driving means for driving the pressure reducing device for both heating and cooling in accordance with the above, it is possible to increase the cooling and heating capacity without impairing the reliability of the compressor during both cooling and heating operation and even when the outdoor load fluctuates. A device can be provided.

[Brief description of drawings]

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

FIG. 2 is a control flowchart of the heating / cooling decompression device of the embodiment.

FIG. 3 is a characteristic diagram showing a correlation between a set intermediate pressure and an outside air temperature during a cooling operation of the embodiment.

FIG. 4 is a characteristic diagram showing a correlation between a set intermediate pressure during heating operation and an outside air temperature in the same embodiment.

FIG. 5: Refrigerant cycle diagram of a conventional cooling and heating device

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 10 Open / close valve 11 Injection pipe 12 Cooling decompression device 13 Cooling check valve 14 Gas-liquid separator 15 Cooling / heating decompression device 16 Indoor heat exchanger 19 Heating check Valve 20 Heating decompression device 21 Outside air temperature detection means 22 Intermediate pressure detection means 24 Cooling / heating mode determination means 25 Set intermediate pressure calculation means 26 Intermediate pressure determination means 27 Decompression amount determination means 28 Decompression device drive means

Claims (1)

[Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger, a cooling decompression device, a cooling check valve, a gas-liquid separator, a cooling / heating decompression device with variable decompression amount, and an indoor heat exchanger, which are connected in order. An injection pipe having an opening / closing valve that connects the heating check valve and the heating pressure reducing device, which are located in parallel with the cooling pressure reducing device and the cooling check valve, and connects the gas-liquid separator and the compressor to each other. An outside air temperature detecting means for detecting the outside air temperature, an intermediate pressure detecting means for detecting the pressure of the gas-liquid separator, a cooling / heating mode determining means for determining cooling or heating, and an outside air detected by the outside air temperature detecting means. A set intermediate pressure calculating means for calculating a set value of the intermediate pressure based on the temperature according to cooling and heating, an intermediate pressure determining means for comparing and comparing the calculation result with the pressure detected by the intermediate pressure detecting means, and this determination result Depending on the A cooling / heating apparatus comprising: a decompression amount determination means for determining the decompression amount of 1. and a decompression device driving means for driving the cooling / heating decompression device according to the decompression amount.