JPH05302767A - Space cooling and heating device - Google Patents

Abstract

PURPOSE:To provide a space cooling and heating device in which a gas injection can be used without damaging a reliability in operation of a compressor even in the case that both cooling and heating operations are being carried out and an indoor and outdoor load is varied. CONSTITUTION:There are provided a discharging pressure sensing means 21 for use in detecting a discharging pressure of a compressor 1, an intermediate pressure sensing means 22 for sensing an intermediate pressure of a gas-liquid separator 14, a cooling or heating mode discriminating means 24 for discriminating either a cooling operation or a heating operation and a set intermediate pressure calculating means 25 for calculating a set intermediate pressure in response to a discharging pressure. In addition, there are provided an intermediate pressure discriminating means 26 for comparing and discriminating a result of calculation with an intermediate pressure, a pressure reducing amount discriminating means 27 for discriminating a pressure reducing amount of a cooling or heating pressure reducing device 15 in response to a result of the discrimination and a pressure reducing device driving means 28 for driving the cooling or heating pressure reducing device 15 in response to the pressure reducing amount.

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 / 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 known from 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 decompression device 6 and sent to the gas-liquid separator 5.

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 through the indoor heat exchanger 7 by the amount of this gas refrigerant. The amount increases and the heating capacity increases.

[0010]

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 heating and cooling operations, the liquid refrigerant flows into the compressor 1 through the injection pipe 11 during either operation,
There was a problem of impairing the reliability of the compressor 1.

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

The present invention solves the above-mentioned problems, and gas injection can be used without impairing the reliability of the compressor during both heating and cooling operations, and also when the outdoor load and indoor load fluctuate, and the cooling and heating capacity is improved. It is an object of the present invention to provide an air conditioning system that can increase the power consumption.

[0013]

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 a reduced pressure amount. 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 that connects the gas-liquid separator and the compressor, and the pressure at the outlet of the compressor. Discharge pressure detecting means for detecting, 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 intermediate pressure of the 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 heating and cooling, an intermediate pressure determining means for comparing and comparing the calculated result and the pressure detected by the intermediate pressure detecting means, and a heating / cooling decompression device according to the determination result. Decompression to judge decompression amount 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, when the cooling / heating mode determining means determines the cooling operation, the intermediate pressure suitable for the cooling operation is set based on the discharge pressure detected by the discharge pressure detecting means. Calculated by the means, the result and the pressure detected by the intermediate pressure detection means are compared and determined by the intermediate pressure determination means, and the reduced pressure amount is determined by the reduced pressure amount determination means according to the result,
The decompression device driving means drives the cooling / heating decompression device.

When the cooling / heating mode determination means determines that the heating operation is performed, the intermediate pressure suitable for the heating operation is calculated by the set intermediate pressure calculation means based on the discharge pressure detected by the discharge pressure detection 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 and the indoor load fluctuate during both heating and cooling operations, and the inflow of liquid refrigerant from the injection pipe to the compressor is prevented.

[0017]

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 an air conditioner according to the present embodiment, FIG. 2 is a control flowchart of a heating / cooling decompression device, FIG. 3 is a characteristic diagram showing a correlation between a set intermediate pressure and a compressor discharge pressure during a cooling operation, and FIG. It is a characteristic view which shows the correlation of the setting intermediate pressure at the time of heating operation, and compressor discharge pressure. still,
The same components as those of the related art will be designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 12 is a cooling decompressor, 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 17.

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 combined pressure reducing 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 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 decompression device 20 are installed in parallel with the cooling / heating decompression device 12 and the cooling check valve 13.

Reference numeral 21 denotes a discharge pressure detecting means, which is the compressor 1
A pressure sensor is attached to the discharge pipe. 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 17.

Reference numeral 24 is a cooling / heating mode determining means, which determines whether it is 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 means, which determines a set intermediate pressure suitable for cooling / heating operation based on the pressure detected by the discharge pressure 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. 28 is a pressure reducing 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 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 device 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 as to be a set intermediate pressure, and the heat is evaporated by 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, and then electrically driven. The expansion valve 15 adjusts the pressure in the gas-liquid separator 14 so as to be a set intermediate pressure. And the gas-liquid separator 1
The refrigerant discharged from No. 4 is depressurized by the heating decompression device 20, passes through the heating check valve 19 and is endothermicly evaporated in the outdoor heat exchanger 3, passes through the four-way valve 2 and the accumulator 8, and circulates to the compressor 1.

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 discharge pressure detection means 21.
Therefore, the discharge pressure Pd of the compressor 1 is detected by the pressure sensor, and the process 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. In step 3, the cooling / heating mode determination means 24 determines whether cooling or heating is performed based on the signal from the remote controller 23. When the cooling operation is performed, 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 × Pd + 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 discharge pressure Pd have a correlation as shown in FIG. 3, and the constant a = 0.5, b =
It becomes 0.

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, it is determined that the opening degree of the electric expansion valve 15 is "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" 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 returns to step 1.

When the heating operation is determined in step 3,
Go to step 10. Step 10 is the set intermediate pressure calculation means 25, which calculates the set intermediate pressure Phm during heating using the equation Phm = c × Pd + d and shifts to step 11. In this equation, it is known from the experiments by the inventors that the proper set intermediate pressure Phm and the discharge pressure Pd have a correlation as shown in FIG. 4, and the constant c = 0.75,
d = −0.8.

Step 11 is the intermediate pressure determining means 26. When the intermediate pressure Pm and the set intermediate pressure Phm 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 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 the value is larger than m, the process proceeds to step 13.

Step 13 is the decompression 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 then 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 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 is injected from the injection pipe 11 to the compressor 1 during both heating and cooling operation and also when the outdoor load and the indoor load change. The refrigerant can be prevented from flowing in, and the cooling and 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 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 that connects the gas-liquid separator and the compressor, and a discharge that detects the pressure at the outlet of the compressor. Pressure detection means, intermediate pressure detection means for detecting the pressure of the gas-liquid separator, cooling / heating mode determination means for determining cooling or heating, and a set value of the intermediate pressure based on the pressure detected by the discharge pressure detection means. The intermediate pressure determination means for comparing the calculated result with the pressure detected by the intermediate pressure detection means, and the reduced pressure amount of the cooling / heating decompression device according to the determination result. Decompression amount determination means to By providing the pressure reducing device driving means for driving the heating / cooling decompression device according to the pressure amount, cooling / heating is performed without impairing the reliability of the compressor during both heating and cooling operations, and when the outdoor load and the indoor load fluctuate. It is possible to provide an air conditioner that can increase the capacity.

[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 a compressor discharge pressure during a cooling operation of the embodiment.

FIG. 4 is a characteristic diagram showing a correlation between a set intermediate pressure and a compressor discharge pressure during heating operation 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 Opening / closing valve 11 Injection pipe 12 Cooling decompressor 13 Cooling check valve 14 Gas-liquid separator 15 Cooling / heating decompressor 16 Indoor heat exchanger 19 Heating check Valve 20 Heating decompression device 21 Discharge pressure 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 pressure reducing device, a cooling check valve, a gas-liquid separator, a cooling / heating pressure reducing device with variable pressure reduction amount, and an indoor heat exchanger are sequentially connected. Then, an injection pipe having an opening / closing valve that connects the heating check valve and the heating pressure reducing apparatus, which are located in parallel with the cooling pressure reducing apparatus and the cooling check valve, and connects the gas-liquid separator and the compressor to each other. A discharge pressure detecting means for detecting the pressure of the compressor outlet, 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,
A set intermediate pressure calculating means for calculating a set value of the intermediate pressure according to the cooling and heating based on the pressure detected by the discharge pressure detecting means, and an intermediate judgment for comparing the calculation result with the pressure detected by the intermediate pressure detecting means. A pressure determining means, a decompression amount determining means for determining a decompression amount of the cooling / heating decompression device according to the determination result, and a decompression device driving means for driving the cooling / heating decompression device according to the decompression amount. Air conditioner.