JP2854098B2 - Air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly, to an air conditioner in which an interior part and a perimeter part in a building can be individually cooled or heated by a plurality of use side heat exchangers. The present invention relates to an air conditioner that has been manufactured.

[Conventional technology]

Generally, the interior of a building is divided into a central interior section and a perimeter section facing the outer wall. And in recent years, with the increase of OA equipment etc. placed in the central interior part, the period of cooling of the interior part is increasing,
For example, in the middle period, the central interior is cooled while the perimeter facing the outer wall is heated.

In response to this, in the conventional air conditioner, a plurality of use side units are connected to the heat source side unit, and these use side units are separately arranged in the interior part and the perimeter section of the building, and the inside of the use side unit is A dedicated on / off switching valve for switching the refrigerant flow path is provided to allow the use side heat exchanger to function as a condenser or evaporator, and the interior and perimeter sections are individually turned on and off by this switching valve. Cooling or heating (JP-A-63-27)
No. 9063).

[Problems to be solved by the invention]

However, in the conventional apparatus, when cooling and heating the other while heating the other, for example, when the cooling and heating operation is performed in winter, the gas pressure of the low-pressure gas is reduced depending on the outside air temperature, and the gas pressure is reduced. When extremely lowered, the use side heat exchanger acting as an evaporator freezes to reduce the cooling capacity, or the freezing cools the housing of the use side unit and condenses on the outer surface, There is a problem.

Further, in the conventional type, when the cooling and heating operation is performed, for example, in summer, the gas pressure of the high-pressure gas increases depending on the outside air temperature, and when the gas pressure rises extremely, it acts as a condenser. There is a problem that the heating capacity of the use-side heat exchanger is too high.

Therefore, an object of the present invention is to solve the above-described problems of the conventional technology, to prevent the freezing and dew condensation of the use side heat exchanger in winter and to significantly increase the heating capacity of the use side heat exchanger in summer. It is an object of the present invention to provide an air conditioner capable of preventing the occurrence of air pollution.

[Means for solving the problem]

In order to achieve the above object, the present invention connects a heat source side unit incorporating a compressor and a heat source side heat exchanger to a plurality of utilization side units incorporating a utilization side heat exchanger by unit piping. The heat source side heat exchanger is branched and connected to a refrigerant discharge pipe and a refrigerant suction pipe of a compressor via a switching valve, while the inter-unit pipe is a high pressure gas pipe branched and connected to the discharge pipe; A low-pressure gas pipe branched and connected to
A liquid pipe connected to a heat source side heat exchanger is connected. Each of the utilization side heat exchangers is branched and connected to the high-pressure gas pipe and the low-pressure gas pipe via a switching valve. In the air conditioner connected via a heat exchanger, the switching valve connected to the use side heat exchanger has a valve opening gradually and linearly depending on the pressure or temperature of the refrigerant in the use side heat exchanger. It is characterized by being constituted by a capacity adjusting valve to be increased or decreased.

(Operation)

According to the present invention, the switching valve for the low-pressure gas and the switching valve for the high-pressure gas are configured by a capacity adjusting valve including a proportional control valve, a stepped control valve, and the like. Unlike the switching valve of the above, since the valve opening is gradually and linearly increased and decreased, the capacity of the refrigerant flowing into and out of the use side heat exchanger is smoothly and effectively controlled, and thus the use side heat exchange Depending on the heat load of the heat exchanger, the evaporating pressure can be increased linearly during cooling, eliminating the problem of freezing and dew condensation on the use side heat exchanger, and the condensing pressure can be reduced linearly during heating, The problem of a significant increase in the heating capacity of the use side heat exchanger is eliminated.

〔Example〕

Hereinafter, an embodiment of an air conditioner according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a heat source side unit,
The use side units 5A to 5D are connected to the heat source side unit 1 via the unit piping 3. The heat source side unit 1 incorporates a compressor 21, a gas-liquid separator 22, and a heat source side heat exchanger 23.
The switching valve 25a and the second switching valve 25b are connected. The first switching valve 25a is connected to a refrigerant discharge pipe 27 of the compressor 21,
The second switching valve 25b is connected to a refrigerant suction pipe 28 of the compressor 21.

The inter-unit pipe 3 includes a liquid pipe 31, a high-pressure gas pipe 32, and a low-pressure gas pipe 33. The liquid pipe 31 is connected to the heat source side heat exchanger 23 via a refrigerant pressure reducer 29 such as an electric expansion valve. ing. The high-pressure gas pipe 32 is connected to the refrigerant discharge pipe 27, and the low-pressure gas pipe 33 is connected to the refrigerant suction pipe. Also, liquid tube
31 is branched, and each branch liquid pipe 31a-31d is connected to four use-side heat exchangers 51 via refrigerant decompressors 35A-35D such as electric expansion valves.
A to 51D respectively.

The four use-side heat exchangers 51A to 51D are incorporated in each of the use-side units 5A to 5D described above. The low-pressure gas switching valves 37A-37D and the high-pressure gas switching valves 38A-38D are connected to the respective use side heat exchangers 51A-51D, and the low-pressure gas switching valves
37A to 37D are branched low-pressure gas pipes branched from the low-pressure gas pipe 33
33a to 33d. High pressure gas switching valve 38A-38D
Are high pressure gas pipes 32a to 32d branched from the high pressure gas pipe 32.
It is connected to the. The above configuration is almost the same as the conventional one.

According to this embodiment, each of the use-side heat exchangers 51A to 51D is provided with a sensor 52A to 52D for detecting the temperature or pressure of the refrigerant flowing in the heat exchanger. Are connected to the controllers 53A to 53D. The controllers 53A to 53D are connected to actuators of low-pressure gas switching valves 37A to 37D and high-pressure gas switching valves 38A to 38D.

Further, according to this embodiment, the low-pressure gas switching valves 37A to 37A
The 7D and high-pressure gas switching valves 38A to 38D are constituted by so-called capacity adjusting valves including a proportional control valve and a stepped control valve, and these capacity adjusting valves are signals output from the controllers 53A to 53D. , That is, in accordance with the temperature or the pressure of the refrigerant flowing through the use-side heat exchangers 51A to 51D, the valve opening is gradually and linearly increased and decreased.

 Next, the operation of this embodiment will be described.

When simultaneous cooling is performed by all the use side heat exchangers 51A to 51D, the first switching valve 25 connected to the heat source side heat exchanger 23 is used.
a is opened and the second switching valve 25b is closed. Low-pressure gas switching valves 37A to 37D connected to the use side heat exchangers 51A to 51D
Is opened, and the high-pressure gas switching valves 38A to 38D are closed.

When the switching valve is opened and closed in this manner, the refrigerant discharged from the compressor 21 flows sequentially through the refrigerant discharge pipe 27, the first switching valve 25a, and the heat source side heat exchanger 23, where it is condensed and liquefied. Via the liquid pipe 31 and the branch liquid pipes 31a to 31d, they are distributed to the respective refrigerant decompressors 35A to 35D and decompressed. Thereafter, each of the use side heat exchangers 51A to 51D vaporizes and evaporates, and switches the low pressure gas switching valves 37A to 37D, the branch low pressure gas pipes 33a to 33d, the low pressure gas pipe 33, the refrigerant suction pipe 28, and the gas-liquid separator 22. The refrigerant is sucked into the compressor 21 sequentially. That is, when cooling at the same time,
All the use side heat exchangers 51A to 51D use as evaporators, from which cool air is sent.

On the other hand, when simultaneous heating is performed by all the use-side heat exchangers 51A to 51D, the opening and closing operation of the valve is reversed from that in the above-described simultaneous cooling. That is, the first switching valve 25a connected to the heat source side heat exchanger 23 is closed, and the second switching valve 25b is opened. Further, the low-pressure gas switching valves 37A to 37D connected to the use side heat exchangers 51A to 51D are closed, and the high-pressure gas switching valve 38 is closed.
Open A ~ 38D.

When the switching valve is opened and closed in this way, the refrigerant discharged from the compressor 21 sequentially passes through the refrigerant discharge pipe 27, the high-pressure gas pipe 32, the branch high-pressure gas pipes 32a to 32d, and the high-pressure gas switching valves 38A to 38D. It is distributed to each use side heat exchanger 51A-51D.
After being condensed and liquefied here, the pressure is reduced by the refrigerant decompressors 35A to 35D, the liquids are merged in the liquid pipe 31 through the branch liquid pipes 31a to 31d, and thereafter, the liquid is evaporated and vaporized in the heat source side heat exchanger 23, and then the second switching is performed. The refrigerant is sucked into the compressor 21 through the valve 25b, the refrigerant suction pipe 28, and the gas-liquid separator 22 sequentially. That is, in the case of heating at the same time,
All the use side heat exchangers 51A to 51D act as condensers, from which warm air is delivered.

Further, according to this embodiment, the use-side heat exchangers 51A to 51D can be individually operated as evaporators or condensers by opening and closing the switching valve to individually perform cooling and heating.

For example, when only the right-side use-side heat exchanger 51D among the use-side heat exchangers 51A to 51D is used for cooling and the rest is used for heating, the first switching valve connected to the heat-source-side heat exchanger 23 is used. 25a
Is closed, and the second switching valve 25b is opened. Further, the low-pressure gas switching valve 37D and the high-pressure gas switching valve 38A-38C connected to the use side heat exchangers 51A-51D are opened, and the low-pressure gas switching valves 37A-37C and the high-pressure gas switching valve 38D are opened. To close.

Thus, the refrigerant discharged from the compressor 21 flows sequentially through the refrigerant discharge pipe 27, the high-pressure gas pipe 32, the branch high-pressure gas pipes 32a to 32c, the high-pressure gas switching valves 38A to 38C, and the use side heat exchangers 51A to 51C. , And is condensed and liquefied in each of the heat exchangers 51A to 51C. The refrigerant liquefied in the use-side heat exchangers 51A to 51C joins in the liquid pipe 31, a part of the refrigerant is distributed to the refrigerant decompressor 29, and the remaining refrigerant is distributed to the refrigerant decompressor 35D. The pressure is reduced. Thereafter, the refrigerant evaporated and vaporized in the heat source side heat exchanger 23 passes through the switching valve 25b, and the refrigerant evaporated and vaporized in the use side heat exchanger 51D is switched to the low pressure gas switching valve 37D, the branch low pressure gas pipe 33b, and the low pressure gas pipe. The refrigerant is sequentially sucked into the compressor 21 through the refrigerant suction pipe 28 and the gas-liquid separator 22.

That is, when only the right end is used for cooling and the rest is used for heating, the use-side heat exchangers 51A to 51C are operated as condensers, and while the warm air is sent out therefrom, the use-side heat exchangers 51A to 51C are used.
D acts as an evaporator, from which cool air is delivered.

By the way, when such an operation is performed in winter, the gas pressure in the low-pressure gas pipe 33 decreases depending on the outside air temperature because the heat source side heat exchanger 23 is an evaporator. When the gas pressure is extremely reduced, the use-side heat exchanger 51D acting as an evaporator freezes to reduce the cooling capacity, and the freezing cools the outside of the use-side unit 5D. Condensation forms on the surface.

In such a case, in this embodiment, a signal from the controller 52D that is issued based on a detection signal from the sensor 52D is controlled to reduce the valve opening of the low-pressure gas switching valve 37D, and The amount of refrigerant flowing out of the heat exchanger 51D is reduced, and the evaporating pressure in the use side heat exchanger 51D is increased, thereby suppressing freezing and dew condensation of the use side heat exchanger 51D.

On the other hand, the cooling and heating operations described above are, for example,
In the summer, since the heat source side heat exchanger 23 is an evaporator, the gas pressure of the high-pressure gas pipe 32 increases depending on the outside air temperature, and when this gas pressure rises extremely,
Three user-side heat exchangers 51A-5 acting as condensers
The heating capacity of 1C increases significantly.

In such a case, in this embodiment, the sensors 52A to 52C
Controllers 53A to 53C issued based on detection signals from
The high-pressure gas switching valves 38A to 38C are controlled such that the valve openings thereof become small, the amount of refrigerant flowing into the three use side heat exchangers 51A to 51C is reduced, and the use side heat exchange is performed. The condensing pressure in the heat exchangers 51A to 51C is reduced, and a remarkable increase in the heating capacity of the use-side heat exchangers 51A to 51C is suppressed.

Thus, according to the present embodiment, the low-pressure gas switching valve 37A
To 37D and the high-pressure gas switching valves 38A to 38D are configured by capacity adjusting valves including a proportional control valve, a stepped control valve, and the like. Since the valve opening is gradually and linearly increased and decreased, the capacity control of the refrigerant is performed smoothly and effectively.

Therefore, according to the present embodiment, the evaporation pressure can be linearly increased during cooling according to the heat load of the use side heat exchanger, so that the problem of freezing and dew condensation of the use side heat exchanger can be solved. In addition, since the condensing pressure can be reduced linearly during heating, various effects can be obtained such as the problem that the heating capacity of the use side heat exchanger is significantly increased.

The above describes an example in which one unit is used for cooling and the remaining three units are used for heating. However, the present invention is not limited to this. For example, only the right end use side heat exchanger 51D is used for heating, It goes without saying that the present invention can be applied to any of the cases where the remaining three units are used for cooling or two units are used for cooling and heating.

In the above embodiment, the heat source side heat exchanger 23 is an air-cooled type.However, the present invention is not limited to this, and the heat source side heat exchanger 23 is a water-cooled type in which a refrigerant exchanges heat with water. It may be.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the switching valve connected to the use side heat exchanger has a valve opening gradually and linearly depending on the pressure or temperature of the refrigerant in the use side heat exchanger. Unlike the conventional ON / OFF switching valve, the valve opening gradually increases and decreases linearly, so that it flows into the use side heat exchanger. In addition, the capacity of the refrigerant flowing out can be controlled smoothly and effectively. Therefore, according to the heat load of the use side heat exchanger, the evaporating pressure can be increased linearly during cooling, so that the problem of freezing and dew condensation of the use side heat exchanger can be eliminated. Since the temperature can be reduced linearly, various effects can be obtained, such as the problem that the heating capacity of the use-side heat exchanger increases can be solved.

[Brief description of the drawings]

The drawing is a refrigerant circuit diagram showing an embodiment of the air conditioner according to the present invention. 1 ... heat source side unit, 3 ... unit piping, 5 ...
User side unit, 21 Compressor, 23 Heat source side heat exchanger, 32 High pressure gas pipe, 32a to 32d Branch high pressure gas pipe
33 …… Low-pressure gas pipe, 33a-33d …… Branch low-pressure gas pipe, 37…
… Switching valve for low pressure gas, 38 …… Switching valve for high pressure gas, 51 ……
User side heat exchanger.

Claims (1)

(57) [Claims] 1. A heat source side heat exchanger in which a heat source side unit in which a compressor and a heat source side heat exchanger are incorporated and a plurality of user side units in which a use side heat exchanger is incorporated are connected by unit piping. Is connected to the refrigerant discharge pipe and the refrigerant suction pipe of the compressor via a switching valve, while the inter-unit pipe is a high-pressure gas pipe branched and connected to the discharge pipe, and the low-pressure gas branched and connected to the suction pipe. And a liquid pipe connected to the heat source side heat exchanger. Each of the use side heat exchangers is branched and connected to the high pressure gas pipe and the low pressure gas pipe via a switching valve, and is connected to the liquid pipe. Is an air conditioner connected via a refrigerant decompressor, wherein the switching valve connected to the use side heat exchanger has a valve opening gradually and according to the pressure or temperature of the refrigerant in the use side heat exchanger. It is characterized by being composed of a capacity adjustment valve that increases or decreases linearly. Air conditioner to be featured.