JP3036525B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having an outdoor unit and an indoor unit connected by a communication pipe.

[0002]

2. Description of the Related Art Conventionally, an air conditioner includes a refrigerant circuit in which a compressor of an outdoor unit, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger of an indoor unit are connected in a ring shape. . In this air conditioner, an outdoor unit and an indoor unit are connected by a communication pipe in which a refrigerant pipe is covered with a heat insulating material.

[0003]

As shown in FIG. 3, in the air conditioner, an outdoor unit 41 installed outside the room and an indoor unit 42 installed on the ceiling 51 inside the room are connected to each other. The connection is made via a communication pipe 43 passing through the space 52 and the wall 53. When the air conditioner performs a cooling operation in a hot and humid environment, the outdoor unit 4
Since the surface temperature of the connecting pipe 43 connecting the first unit 1 and the indoor unit 42 becomes lower than the dew point temperature, dew condensation occurs in the space 52 behind the ceiling of the connecting pipe 43, and the condensed water drops on the ceiling. There is a problem that stains and the like occur.

It is an object of the present invention to provide an air conditioner which can prevent dew condensation on a communication pipe disposed behind a ceiling or the like, thereby preventing the ceiling from being stained or the like.

[0005]

In order to achieve the above object, an air conditioner according to the first aspect of the present invention includes a compressor of an outdoor unit,
An air conditioner comprising an outdoor heat exchanger, an electric expansion valve, and a refrigerant circuit in which an indoor heat exchanger of an indoor unit is annularly connected, and wherein the outdoor unit and the indoor unit are connected by a communication pipe, A temperature sensor that is disposed on the outdoor unit side of the pipe and detects a temperature of a refrigerant flowing from an outlet side of the indoor heat exchanger of the indoor unit to a suction side of the compressor of the outdoor unit during a cooling operation; and Based on the detected temperature of the refrigerant, so that the temperature of the refrigerant flowing from the outlet side of the indoor heat exchanger to the suction side of the compressor of the outdoor unit becomes 8 ° C. or more,
An electric expansion valve opening correction unit for correcting the opening of the electric expansion valve is provided.

According to the air conditioner of the first aspect, during the cooling operation, the refrigerant discharged from the compressor of the outdoor unit is condensed in the outdoor heat exchanger to release heat to the outside air, and the condensed refrigerant is discharged. The refrigerant is expanded by an electric expansion valve to reduce the pressure, and the refrigerant is evaporated in the indoor heat exchanger of the indoor unit to absorb heat from the indoor air, and then returned to the suction side of the compressor. The temperature of the refrigerant flowing from the outlet side of the indoor heat exchanger of the indoor unit to the suction side of the compressor of the outdoor unit is detected by a temperature sensor disposed on the outdoor unit side of the communication pipe.
Based on the temperature of the refrigerant detected by the temperature sensor, the temperature of the refrigerant flowing from the outlet side of the indoor heat exchanger to the suction side of the compressor of the outdoor unit becomes 8 ° C. or higher by the electric expansion valve opening correction unit. Thus, the opening of the electric expansion valve is corrected. That is, by correcting the degree of opening of the electric expansion valve and making the refrigerant on the outlet side of the indoor heat exchanger into a gas state to increase the degree of superheat, the compression of the outdoor unit from the outlet side of the indoor heat exchanger is performed. The surface temperature of the connecting pipe through which the refrigerant flows to the suction side of the machine is set to be higher than the dew point temperature. According to an experiment conducted by the present applicant, in a general communication pipe in which the outside of a refrigerant pipe is covered with a heat insulating material, the refrigerant temperature in the refrigerant pipe is set at 8 ° C.
It was found that when the temperature was set to not less than ° C, the surface temperature of the heat insulating material was approximately 25 ° C or more, and did not exceed the outdoor temperature in a high-temperature and high-humidity environment. Therefore,
By setting the temperature of the refrigerant flowing from the outlet side of the indoor heat exchanger to the suction side of the compressor of the outdoor unit at 8 ° C. or higher, dew condensation on the communication pipes installed in a space such as the space above the ceiling can be prevented and the ceiling can be formed. Can be prevented from occurring.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an air conditioner according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a schematic configuration diagram of a multi-type air conditioner according to an embodiment of the present invention, wherein 1 is a compressor, 2 is a four-way valve connected to the discharge side of the compressor 1, Is an outdoor heat exchanger having one end connected to the four-way valve 2; 4 is a header having one end connected to the other end of the outdoor heat exchanger 3;
Is an electric expansion valve having one end connected to the other end of the header 4, and 6A to 6D are indoor units each having one end connected to the other end of the electric expansion valves 5A to 5D via communication pipes 11A to 11D. The indoor heat exchanger 7 is the indoor heat exchanger 6A
6D are connected to one end via communication pipes 12A to 12D. Reference numeral 8 denotes one end connected to the other end of the header 7 via the four-way valve 2, and the other end to the compressor 1. The accumulator 10 connected to the suction side of the compressor 1
This is a control device that controls the electric expansion valves 5A to 5D.

A closing valve 24 is provided between the outdoor heat exchanger 3 and the header 4, and a closing valve 25 is provided between the header 7 and the four-way valve 2. Further, a discharge pipe temperature sensor 21 is disposed on the discharge side of the compressor 1, and an outdoor heat exchanger temperature sensor 22 for detecting a refrigerant temperature is disposed in the outdoor heat exchanger 3. Further, the header 7
Connecting pipe 12 that connects each of the indoor heat exchangers 6A to 6D
Refrigerant refrigerant temperature sensors 23A-23 for detecting the refrigerant temperature in the communication pipes 12A-12D on the header 7 side of A-12D.
D are arranged respectively. The compressor 1, the four-way valve 2,
An outdoor unit is constituted by the outdoor heat exchanger 3, the header 4, the electric expansion valves 5A to 5D and the header 7, the control device 10, the discharge pipe temperature sensor 21, the outdoor heat exchanger temperature sensor 22, and the closing valves 23 and 24. .

The control device 10 comprises a microcomputer, an input / output circuit, etc., and controls a discharge pipe temperature control section 10a for controlling a discharge pipe temperature, and an electric expansion valve for correcting the opening of the electric expansion valves 5A to 5D. And an opening correction unit 10b.

FIG. 2 shows the connecting pipes 11A to 11A.
D, 12A to 12D are shown in cross section, and the refrigerant pipe 31 is shown.
, A cylindrical air layer 32 is provided, and a cylindrical heat insulating material 33 is provided outside the air layer 32. As a result of an experiment conducted by the applicant in the communication pipe having the above configuration, assuming that the temperature of the refrigerant flowing through the refrigerant pipe 31 is 8 ° C., the surface temperature of the heat insulating material 33 is approximately 25 ° C. That is, by setting the temperature of the refrigerant flowing through the refrigerant pipe 31 to 8 ° C. or higher, the surface temperature of the heat insulating material 33 becomes higher than approximately 25 ° C., and becomes higher than the dew point temperature 25 ° C. assumed at the time of high temperature and high humidity. Dew condensation does not occur on the surface of the heat insulating material 33.

In the air conditioner having the above structure, as shown in FIG. 1, when the four-way valve 2 is switched to the solid-line switching position and the compressor 1 is operated, the refrigerant discharged from the compressor 1 causes the outdoor heat exchange. The heat is released to the outside air after being condensed by the heat exchanger 3, and the condensed refrigerant is expanded and decompressed by the electric expansion valves 5A to 5D, respectively. Further, the refrigerant is evaporated by the indoor heat exchangers 6A to 6D to convert the refrigerant from the indoor air. Absorb heat and connect pipes 12A-12D
Through the four-way valve 2 and the accumulator 8 to return the refrigerant to the suction side of the compressor 1. At this time, based on the discharge pipe temperature of the compressor 1 detected by the discharge pipe temperature sensor 21, the discharge pipe temperature control unit 10 a controls the electric expansion valve 5.
The discharge pipe temperature is controlled by controlling the degree of opening of A to 5D.

The discharge pipe temperature is controlled by the discharge pipe temperature control section 10a, and the electric expansion valve opening correction section 10b controls the refrigerant temperature in the communication pipes 12A to 12D detected by the refrigerant temperature sensors 23A to 23D. On the basis of,
The openings of the electric expansion valves 5A to 5D are corrected so that the refrigerant temperature in the communication pipes 12A to 12D becomes 8 ° C. or higher. That is, when the temperature of the refrigerant in the communication pipe 12A is lower than 8 ° C., the opening degree of the electric expansion valve 5A is reduced to reduce the flow rate of the refrigerant. Is increased, and the temperature of the refrigerant in the communication pipe 12A is increased. Hereinafter, similarly, the refrigerant pipes 12B to 12B
The openings of the electric expansion valves 5B to 5D are adjusted according to the refrigerant temperature in 12D.

As described above, the electric expansion valve opening correction section 1
By correcting the opening degree of the electric expansion valves 5A to 5D by 0b and setting the refrigerant temperature in the communication pipes 12A to 12D to 8 ° C or higher, the surface temperature of the heat insulating material becomes approximately 25 ° C or higher,
Since the temperature does not exceed the open-air temperature in a high-temperature and high-humidity environment, dew condensation does not occur on the surface of the heat insulating material of the communication pipes 12A to 12D. Can be prevented.

In the above embodiment, the multi-type air conditioner has been described. However, the present invention may be applied to an air conditioner having one indoor unit.

[0016]

As is apparent from the above description, in the air conditioner of the first aspect of the present invention, the compressor of the outdoor unit, the outdoor heat exchanger, the electric expansion valve, and the indoor heat exchanger of the indoor unit are annularly connected. In the air conditioner provided with a connected refrigerant circuit, the outdoor unit and the indoor unit are connected by a communication pipe, and a temperature sensor arranged on the outdoor unit side of the communication pipe uses the indoor heat of the indoor unit during cooling operation. The temperature of the refrigerant flowing from the outlet side of the exchanger to the suction side of the compressor of the outdoor unit is detected, and based on the detected temperature of the refrigerant, the suction of the compressor of the outdoor unit from the outlet side of the indoor heat exchanger. The electric expansion valve opening correction unit corrects the opening of the electric expansion valve so that the temperature of the refrigerant flowing to the side becomes 8 ° C. or higher.

Therefore, according to the air conditioner of the present invention, during the cooling operation, the temperature of the refrigerant flowing from the outlet side of the indoor heat exchanger to the suction side of the compressor of the outdoor unit detected by the temperature sensor is detected. Based on the above, the opening of the electric expansion valve is corrected by the electric expansion valve opening correction section so that the temperature of the refrigerant becomes 8 ° C. or more, and the refrigerant on the outlet side of the indoor heat exchanger is turned into a gas state. By increasing the degree of superheating, the surface temperature of the above-mentioned connecting pipe is made higher than the dew point temperature at high temperature and high humidity, preventing condensation of the connecting pipe installed in a space such as the ceiling above and preventing stains on the ceiling. This can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a communication pipe of the air conditioner.

FIG. 3 is a cross-sectional view showing a state in a building of a communication pipe connecting an outdoor unit and an indoor unit of the air conditioner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger, 4,7 ...
Header, 5A-5D: electric expansion valve, 6A-6D: indoor heat exchanger, 8: accumulator, 10: control device, 10a
... Discharge pipe temperature control section, 10b ... Electric expansion valve opening degree correction section,
11A to 11D, 12A to 12D: communication pipe, 21: discharge pipe temperature sensor, 22: outdoor heat exchanger temperature sensor, 23
A to 23D: refrigerant temperature sensors.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 59-79777 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 11/02 102

Claims (1)

(57) [Claims] 1. An outdoor unit compressor (1), an outdoor heat exchanger (3), an electric expansion valve (5A-5D) and an indoor heat exchanger (6A-6D) of an indoor unit are connected in a ring shape. An air conditioner comprising a refrigerant circuit, wherein the outdoor unit and the indoor unit are connected by communication pipes (11A to 11D, 12A to 12D), which is disposed on the outdoor unit side of the communication pipes (12A to 12D). During the cooling operation, the compressor of the outdoor unit from the outlet side of the indoor heat exchangers (6A to 6D) of the indoor unit
(1) Temperature sensor that detects the temperature of the refrigerant flowing to the suction side
(23A to 23D) and the temperature of the refrigerant detected by the temperature sensors (23A to 23D), from the outlet side of the indoor heat exchanger (6A to 6D) to the compressor (1) of the outdoor unit. An electric expansion valve opening correction unit that corrects the opening of the electric expansion valves (5A to 5D) so that the temperature of the refrigerant flowing to the suction side becomes 8 ° C. or higher.
(10b) An air conditioner comprising: