JP3231393B2 - Air conditioning - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of a cooling / heating device provided with gas injection.

[0002]

2. Description of the Related Art The prior art is disclosed in Japanese Patent Application Laid-Open No. 57-124.
There is an air conditioner as disclosed in Japanese Patent No. 661.

[0003] The prior art 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 decompression device consisting of a capillary, 5 is a gas-liquid separator, 6 is a second decompression device consisting of a capillary, 7 Is an indoor heat exchanger, 8 is an accumulator,
These are communicated via a refrigerant pipe 9 to constitute a refrigerant cycle.

[0004] Reference numeral 10 denotes an on-off valve, which is provided in an injection pipe 11 that communicates the compressor 1 with the upper part of the gas-liquid separator 5.

[0005] The operation of the air conditioner configured as described 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 and high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 and releases heat in the outdoor heat exchanger 3 to condense and liquefy. 4 at intermediate pressure (about 1MP
The pressure is reduced 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, absorbed and 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 is guided from the gas-liquid separator 5 to the compressor 1 through the injection pipe 11, so that the liquid refrigerant having a small enthalpy flows into the indoor heat exchanger 7, The cooling capacity increases.

On the other hand, during the heating operation, the refrigerant cycle indicated by the dashed arrow in FIG. 5 is performed, and the high-temperature and high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 and releases 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 device 6 and sent to the gas-liquid separator 5.

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

[0010]

However, in the above configuration, the pressure reduction amounts of the first pressure reducing device 4 and the second pressure reducing device 6 are constant in spite of the difference in the proper intermediate pressure in the cooling and heating operation. When gas injection is used in both the cooling and heating operations, the liquid refrigerant flows into the compressor 1 through the injection pipe 11 during either operation,
There was a problem that the reliability of the compressor 1 was impaired.

Further, since the decompression amounts of the first decompression device 4 and the second decompression device 6 are constant, even when the outdoor load and the indoor load fluctuate and the refrigerant circulation amount fluctuates, the liquid refrigerant is injected into the injection pipe 11. Flows into the compressor 1 through the compressor 1
Had the problem of impairing the reliability of the

The present invention has been made to solve the above-mentioned problems, and it is possible to use gas injection without impairing the reliability of a compressor during both cooling and heating operations, and also when the outdoor load and the indoor load fluctuate. It is an object of the present invention to provide a cooling and heating device capable of increasing the temperature.

[0013]

In order to achieve this object, a cooling and heating apparatus according to the present invention comprises a cooling decompression device, a cooling check valve, a gas-liquid separator, and a cooling / heating decompression device having a variable decompression amount. Check valve for heating and pressure reducing device for heating located in parallel with the pressure reducing device for cooling and the check valve for cooling, an injection pipe having an on-off valve communicating the gas-liquid separator and the compressor, and the pressure at the compressor outlet Discharge pressure detecting means for detecting pressure, intermediate pressure detecting means for detecting the pressure of the gas-liquid separator, cooling / heating mode determining means for determining cooling or heating, and intermediate pressure based on the pressure detected by the discharge pressure detecting means. A set intermediate pressure calculating means for calculating a set value according to cooling and heating; an intermediate pressure determining means for comparing the calculation result with a pressure detected by the intermediate pressure detecting means; and a cooling / heating combined pressure reducing device according to the determined result. Decompression to determine the amount of decompression And determining means has a configuration provided with a pressure reducing device driving means for driving the cooling and heating combined decompressor in response to the pressure reduction amount.

[0014]

According to the present invention, an intermediate pressure suitable for the cooling operation is set based on the discharge pressure detected by the discharge pressure detecting means when the cooling / heating mode determining means determines that the cooling operation is performed. 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 reduced pressure amount is determined by the reduced pressure determining means in accordance with the result,
The cooling / heating decompression device is driven by the decompression device driving means.

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 discharge pressure detected by the discharge pressure detecting means. The pressure detected by the intermediate pressure detecting means is 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, and the cooling / heating pressure reducing device is driven by the pressure reducing device driving means.

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

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a refrigerant cycle diagram of a cooling / heating device in the present embodiment, FIG. 2 is a control flowchart of a cooling / heating combined pressure reducing device, FIG. 3 is a characteristic diagram showing a correlation between a set intermediate pressure and a compressor discharge pressure during cooling operation, and FIG. FIG. 4 is a characteristic diagram illustrating a correlation between a set intermediate pressure and a compressor discharge pressure during a heating operation. still,
The same components as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 12 denotes a cooling decompression device, which operates at a pressure of about 1 M when operated under JIS cooling standard conditions.
A capillary tube capable of reducing the pressure to Pa is used. 13 is a cooling check valve. 14 is a gas-liquid separator. Reference numeral 15 denotes 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 17.

Compressor 1, four-way valve 2, outdoor heat exchanger 3,
Cooling decompression device 12, cooling check valve 13, gas-liquid separator 1
4, the low pressure unit for cooling and heating 15 and the indoor heat exchanger 1
6. The accumulator 8 is connected via a refrigerant pipe 18 to constitute a refrigerant cycle.

Reference numeral 19 denotes a heating check valve. Reference numeral 20 denotes a heating decompression device, which uses a capillary tube capable of reducing the pressure to about 0.6 MPa when operated under JIS heating standard conditions. The heating check valve 19 and the heating pressure reducing device 20 are installed in parallel with the cooling / heating pressure reducing device 12 and the cooling check valve 13.

Reference numeral 21 denotes discharge pressure detecting means,
A pressure sensor is attached to the discharge pipe. Reference numeral 22 denotes an intermediate pressure detecting means, and a pressure sensor is attached to the gas-liquid separator 14. 23 is a remote controller for the indoor unit 17.

Numeral 24 denotes a cooling / heating mode determining means for determining whether to perform a cooling operation or a heating operation according to a signal from the remote controller 23. Reference numeral 25 denotes a set intermediate pressure calculating unit which determines a set intermediate pressure suitable for the cooling / heating operation based on the pressure detected by the discharge pressure detecting unit 21. Reference numeral 26 denotes an intermediate pressure determination unit which determines whether the pressure detected by the intermediate pressure detection unit 22 is higher or lower than the set intermediate pressure. Reference numeral 27 denotes a pressure reduction amount determining 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 determining means 26. 28 is a decompression device driving means,
The number of pulses corresponding to the determination result of the pressure reduction amount determination means 27 is transmitted to the electric expansion valve 15 to be driven.

Reference numeral 29 denotes a control device, which comprises a cooling / heating mode determining means 24, a set intermediate pressure calculating means 25, an intermediate pressure determining means 26, a pressure reducing amount determining means 27, and a pressure reducing device driving means 28.

The operation of the cooling / heating device configured as described above will be described. First, during the cooling operation, the refrigerant cycle indicated by the solid line arrow in FIG. 1 is performed, and the high-temperature and high-pressure gas compressed by the compressor 1 passes through the four-way valve 2 and releases heat in the outdoor heat exchanger 3 to be condensed and liquefied. The pressure is reduced at 12 and is sent to a gas-liquid separator 14 through a cooling check valve 13. And
The pressure inside the gas-liquid separator 14 is adjusted by the electric expansion valve 15 so as to become the set intermediate pressure, and is absorbed and evaporated by the indoor heat exchanger 16 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 is introduced from the gas-liquid separator 14 through the injection pipe 11 to the compressor 1.

On the other hand, during the heating operation, the refrigerant cycle indicated by the dashed arrow in FIG. 1 occurs, and the high-temperature and 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 condense and liquefy. The pressure in the gas-liquid separator 14 is adjusted by the expansion valve 15 so as to become the set intermediate pressure. And the gas-liquid separator 1
The refrigerant discharged from 4 is decompressed by the heating decompression device 20, passes through the heating check valve 19, absorbs and evaporates in 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 on-off 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.
This will be described with reference to FIG. Step 1 is discharge pressure detecting means 21
The discharge pressure Pd of the compressor 1 is detected by the pressure sensor, and the process proceeds to step S2. Step 2 is an intermediate pressure detecting means 22, which detects the intermediate pressure Pm of the gas-liquid separator 14 with a pressure sensor and proceeds to step 3. Step 3 is a cooling / heating mode determining means 24 for determining whether to perform cooling or heating based on a signal from the remote controller 23, and proceeds to step 4 in the cooling operation.

Step 4 is a set intermediate pressure calculating means 25, which calculates the set intermediate pressure Pcm during cooling using the equation Pcm = a × Pd + b, and proceeds to step 5. In this equation, it is known from the experiments of the present inventors that there is a correlation between the appropriate set intermediate pressure Pcm and the discharge pressure Pd as shown in FIG. 3, and from FIG. 3, the constant a = 0.5, b =
It becomes 0.

Step 5 is an intermediate pressure judging means 26. When the intermediate pressure Pm is equal to the set intermediate pressure Pcm, it is judged that the intermediate pressure Pm is appropriate, and the process returns to Step 1, where the intermediate pressure Pm and the set intermediate pressure Pcm are determined. If they are not equal, the process proceeds to step 6. Step 6 is also the intermediate pressure determination means 26, and if 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 a pressure reduction amount determination means 27,
In order to reduce the intermediate pressure Pm, the degree of opening of the electric expansion valve 15 is determined to be “20 pulses open”, and the routine 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 and returns to step 1.

If it is determined in step 6 that the intermediate pressure Pm is smaller than the set intermediate pressure Pcm, the process proceeds to step 8. Step 8 is a pressure reduction amount determination means 27, which sets the opening of the electric expansion valve 15 to "20" 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 reduce the number of pulses by 20 and returns to step 1.

When it is determined in step 3 that the heating operation is performed,
Move to step 10. Step 10 is a set intermediate pressure calculating means 25, which calculates the set intermediate pressure Phm during heating using the formula Phm = c × Pd + d, and proceeds to step 11. In this equation, it is known from the experiments of the inventors that there is a correlation between the appropriate set intermediate pressure Phm and the discharge pressure Pd, and the constant c = 0.75 from FIG.
d = −0.8.

Step 11 is an intermediate pressure judging means 26. When the intermediate pressure Pm is equal to the set intermediate pressure Phm, it is judged that the intermediate pressure Pm is appropriate, and the process returns to step 1, where the intermediate pressure Pm and the set intermediate pressure Phm are determined. If they are not equal, the process proceeds to step 12. Step 12 is also an intermediate pressure determining means 26, and the intermediate pressure Pm is set to the set intermediate pressure Ph.
When it is determined that it is larger than m, the process proceeds to step S13.

Step 13 is a pressure reducing amount determining means 27, which determines the opening of the electric expansion valve 15 to be "20 pulses closed" in order to reduce 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 reduce the number of pulses by 20 and returns to step 1.

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

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

[0038]

As is apparent from the above description, the present invention comprises a cooling decompression device, a cooling check valve, a gas-liquid separator, and a cooling / heating decompression device with a variable decompression amount. A heating check valve and a heating decompression device located in parallel with the cooling check valve, an injection pipe having an on-off valve communicating the gas-liquid separator and the compressor, and a discharge detecting the pressure at the compressor outlet Pressure 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 cooling / heating of the set value of the intermediate pressure based on the pressure detected by the discharge pressure detecting means. Setting intermediate pressure calculating means for calculating in accordance with the above, intermediate pressure determining means for comparing the calculation result with the pressure detected by the intermediate pressure detecting means, and determining the pressure reduction amount of the cooling / heating combined pressure reducing device in accordance with the determination result Means for determining the amount of reduced pressure By providing a decompression device driving means for driving the cooling / heating decompression device according to the pressure amount, the cooling and heating operation can be performed without impairing the reliability of the compressor during both the cooling and heating operations, and also when the outdoor load and the indoor load fluctuate. It is possible to provide a cooling and heating device capable of increasing the capacity.

[Brief description of the drawings]

FIG. 1 is a refrigerant cycle diagram of a cooling and heating device according to an embodiment of the present invention.

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

FIG. 3 is a characteristic diagram showing a correlation between a set intermediate pressure and a compressor discharge pressure during a cooling operation according to the embodiment.

FIG. 4 is a characteristic diagram showing a correlation between a set intermediate pressure and a compressor discharge pressure during a heating operation according to the embodiment.

FIG. 5 is a refrigerant cycle diagram of a conventional cooling / heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 10 On-off 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 pressure reducing device 21 Discharge pressure detecting means 22 Intermediate pressure detecting means 24 Cooling / heating mode determining means 25 Set intermediate pressure calculating means 26 Intermediate pressure determining means 27 Pressure reducing amount determining means 28 Pressure reducing device driving means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References: JP-A 53-13656 (JP, U) Japanese Patent Publication No. 3-11388 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 13/00 311

Claims (1)

(57) [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 variable decompression cooling / heating decompression device, and an indoor heat exchanger. An injection pipe having a cooling check valve, a heating check valve and a heating pressure reducer located in parallel with the cooling check valve, and an on-off valve communicating the gas-liquid separator and the compressor. Discharge pressure detection means for detecting the pressure of the compressor outlet, intermediate pressure detection means for detecting the pressure of the gas-liquid separator, cooling / heating mode determination means for determining cooling or heating,
A set intermediate pressure calculating means for calculating a set value of the intermediate pressure based on the pressure detected by the discharge pressure detecting means in accordance with cooling and heating; and an intermediate for comparing the calculation result with the pressure detected by the intermediate pressure detecting means. Pressure determining means, pressure reducing amount determining means for determining a reduced pressure amount of the cooling / heating combined pressure reducing device according to the determination result, and pressure reducing device driving means for driving the cooling / heating combined pressure reducing device according to the reduced pressure amount. Air conditioning unit.