JP2000314563A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow existing connecting piping to be used as is by providing a pressure-sensing means and a pressure-limiting means when switching a refrigerant from R22 to R410A in an air conditioner of a domestic split heat pump type air conditioner, and operating refrigerating cycle at a set pressure or below the piping thus far. SOLUTION: A compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4 and an outdoor fan 7 are contained in one case to constitute an outdoor unit, and an indoor heat exchanger 6 and an indoor fan 8 are housed in a single case to constitute an indoor unit. The indoor unit is connected to the outdoor unit through connecting piping 5, a refrigerant is replaced from R22 to R410A and filled to constitute a refrigerating cycle. A pressure switch 9 is provided at a discharged pipe of the compressor in association with the replacement of the refrigerant. When a discharging pressure arrives, for example, at 3.16 MPa and the switch 9 is turned off by a main controller, the valve 4 is opened through an expansion valve controller 13. Thus, the discharge pressure is lowered, and conventional connecting piping for the R22 can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a home heat pump type air conditioner, and more particularly, to a technique applied when a refrigerant is switched from R22 to R410A.

[0002]

2. Description of the Related Art Refrigerant R22 used in a home-use separate heat pump air conditioner is an ozone depleting substance, and must be switched to R410A as an alternative refrigerant.

Generally, as shown in FIG. 1, a separate type heat pump air conditioner has a compressor 1, a four-way valve 2,
The outdoor heat exchanger 3, the expansion valve 4, and the outdoor heat exchange fan (hereinafter, indoor fan) 7 are combined into a single box as an outdoor unit, and the indoor heat exchanger 6 and the indoor heat exchange fan ( Hereinafter, a unit in which the outdoor fan (8) is integrated into one box is defined as an indoor unit, and the indoor unit and the outdoor unit are connected by the connection pipe 5 to form a refrigeration cycle.

[0004] Based on the capacity of the refrigeration cycle and the refrigerant used, safety (refrigeration security regulation-related standards and JIS B8
620 “safety standards for small refrigeration equipment”), the design pressure value (high-pressure side rated pressure) is selected.
2.75MPa in case of using, 4.10 in case of R410A
15 MPa.

Here, the connection pipe used in the conventional air conditioner using R22 usually has a copper pipe having a diameter of φ.
6.35, φ9.52, φ12.7 etc., 0.7mm thick
There are many things. From this diameter and thickness, JIS
When the design pressure of the pipe was calculated in consideration of the decay allowance of the pipe in the calculation formula of the water pressure test of the H3300 “copper and copper alloy seamless pipe”, the pipe pressure of φ12.7 was 3.16 MPa, and the R410A described above The design pressure cannot be satisfied.

In addition, JIS for flare joints of piping
It becomes 3.43 Mpa in B8607, and R
It cannot be used in 410A.

Therefore, when using R410A, the thickness of the piping must be increased in order to improve the pressure resistance of the cycle parts due to the difference in design pressure, and the already installed embedded piping or long piping is required. In the case of using a pipe, it is necessary to newly install a pipe. In particular, in the case of a housing air conditioner, embedded pipes or long pipes are often used, which has been a problem in terms of workability and cost.

[0008]

From the above problems, R4
An object of the present invention is to provide an air conditioner that can use a pipe of R22 in a 10A model.

[0009]

In order to solve the above-mentioned problems, the present invention provides an air conditioner which operates a refrigeration cycle at a pressure lower than the design pressure of a conventional connecting pipe by providing a pressure sensing means and a pressure limiting means. Build and allow to use conventional connecting piping.

[0010]

Embodiments of the present invention will be described below.

(1) FIG. 2 shows the air conditioner of the first embodiment. As shown in FIG. 2, the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, and the outdoor fan 7 are combined into a single box as an outdoor unit, and the indoor heat exchanger 6 and the indoor fan 8 are combined into a single box as an indoor unit, and the indoor unit and the outdoor unit are connected by a connection pipe 5 for R22 to form a refrigeration cycle, and a refrigerant R410A is used.

A pressure switch 9 is provided on the compressor discharge pipe. The pressure switch 9 is a device that is turned off when a predetermined pressure is reached.

In the first embodiment, the operation value of the pressure switch 9 is set to the design pressure of the piping (3.16 MPa).

FIG. 3 shows a control configuration of the first embodiment. A main controller 12 is connected to a commercial power supply 10 via a power switch 11. A remote controller 23, a pressure switch 9, an expansion valve controller 13, a compressor controller 14, an indoor fan controller 15, and an outdoor fan controller 16 are connected to the main controller 12. The remote controller 23 sets various operating conditions.

Hereinafter, the control of the first embodiment will be described.

The pressure of the discharge pipe of the compressor 1 is 3.16.
When the pressure reaches MPa, the pressure switch 9 is turned off.

The main controller 12 has a discharge pressure of 3.16MP.
a has been reached, and the expansion valve controller 13
Command to open.

The expansion valve control unit 13 opens the opening of the expansion valve 4.

Since the expansion valve 4 is opened, the discharge pressure decreases.

When the discharge pressure falls below 3.16 MPa, the pressure switch 9 returns and turns on.

The main control unit 12 has a discharge pressure of 3.16M.
It is determined that the pressure has become equal to or less than Pa, and a command is issued to the expansion valve control unit 13 to perform normal control.

When the pressure switch 9 is actuated again
Control.

It is understood from the above control that the discharge pressure is limited to 3.16 MPa or less. Therefore, since the refrigeration cycle of the first embodiment can be operated at a pressure equal to or lower than the design pressure of the pipe, the connection pipe for R22 can be used.

Although the figure shows cooling, it is also effective for heating.

(2) Next, a second embodiment will be described.

In the second embodiment, the refrigeration cycle and the control unit are the same as those in the first embodiment.

The operating value of the pressure switch 9 was set to the design pressure of the piping (3.16 MPa) as in the first embodiment. Hereinafter, control when the pressure switch 9 is operated will be described.

The pressure of the discharge pipe of the compressor 1 is 3.16.
When the pressure reaches MPa, the pressure switch 9 is turned off.

The main controller 12 has a discharge pressure of 3.16MP.
a, and issues a command to the compressor control unit 14 to reduce the compressor speed.

The compressor control section 14 reduces the number of rotations of the compressor.

Since the compressor rotation speed has decreased, the discharge pressure has decreased.

When the discharge pressure falls below 3.16 MPa, the pressure switch 9 returns and turns on.

The main control unit 12 determines that the discharge pressure is 3.16M.
It is determined that the pressure has become Pa or less, and a command is issued to the compressor control unit 14 so as to perform normal control.

When the pressure switch 9 is actuated again
Control.

By the above control, 3.16M
The discharge pressure can be limited to Pa or less, and a connection pipe for R22 can be used.

Although the figure shows cooling, it is also effective during heating.

(3) Next, a third embodiment will be described.

FIG. 4 shows a refrigeration cycle of the third embodiment. In the third embodiment, the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, the connection pipe 5, and the indoor heat exchanger 6 are sequentially connected. Then, a pressure switch 9 and a bypass pipe a are connected to the compressor discharge pipe.
17 from the compressor suction pipe to the bypass pipe b1
8 and further connect the bypass pipes a17 and b18 to the two-way valve 1.
9 is a refrigeration cycle connected.

FIG. 5 shows a control configuration according to the third embodiment. A main controller 12 is connected to a commercial power supply 10 via a power switch 11. The main control unit 12 has a remote control 2 for operation setting.
3, pressure switch 9, expansion valve control unit 13, compressor control unit 14, indoor fan control unit 15, outdoor fan control unit 16,
Then, the two-way valve control unit 20 is connected.

The operating value of the pressure switch 9 was set to the design pressure of the piping (3.16 MPa) as in the first embodiment. Hereinafter, control when the pressure switch 9 operates will be described.

The pressure of the discharge pipe of the compressor 1 is 3.16.
When the pressure reaches MPa, the pressure switch 9 is turned off.

The main controller 12 has a discharge pressure of 3.16MP.
a has been reached, and the two-way valve controller 20
Command to open.

The two-way valve controller 20 opens the two-way valve 19.

Since the two-way valve 19 is opened, the discharge side and the suction side are bypassed, and the high-pressure refrigerant flows toward the low-pressure side of the suction side. Therefore, the discharge pressure decreases.

When the discharge pressure falls below 3.16 MPa, the pressure switch 9 returns and turns on.

The main control unit 12 determines that the discharge pressure is 3.16M.
It is determined that the pressure has become Pa or less, and a command is issued to the two-way valve control unit 20 to close the two-way valve 19.

When the pressure switch 9 is operated again
Control.

It is understood from the above control that the discharge pressure is limited to 3.16 MPa or less. Therefore, since the refrigeration cycle of the third embodiment functions at or below the design pressure of the pipe, the connection pipe for R22 can be used.

Although the figure shows cooling, it is also effective during heating.

(4) Next, a fourth embodiment will be described.

In the fourth embodiment, the refrigeration cycle and the control configuration are the same as those in the first embodiment.

The operating value of the pressure switch 9 was set to the design pressure of the piping (3.16 MPa) as in the first embodiment. Hereinafter, control when the pressure switch 9 operates will be described.

The pressure of the discharge pipe of the compressor 1 is 3.16.
When the pressure reaches MPa, the pressure switch 9 is turned off.

The main controller 12 has a discharge pressure of 3.16MP.
It is determined that a has been reached. At the time of cooling, the refrigerant is condensed in the outdoor heat exchanger 3, so that the outdoor fan control unit 17 is instructed to increase the rotation speed.

The outdoor fan controller 16 controls the outdoor fan 7
Increase the number of revolutions.

Since the rotation speed of the fan has increased, the amount of air passing through the outdoor heat exchanger 3 increases, and the amount of heat exchange increases. Therefore, the temperature of the refrigerant in the condensing heat exchanger decreases, and the refrigerant lowers the condensing pressure. As a result, the discharge pressure also decreases.

When the discharge pressure falls below 3.16 MPa, the pressure switch 9 returns and turns on.

The main control unit 12 determines that the discharge pressure is 3.16M.
It is determined that the pressure has become Pa or less, and a command is issued to the outdoor fan control unit 16 so that normal control is performed.

When the pressure switch 9 is actuated again
Control.

By the above control, 3.16M
The discharge pressure can be limited to Pa or less, and a connection pipe for R22 can be used.

Although the figure shows the time of cooling, it is also effective at the time of heating. At the time of heating, the refrigerant is condensed in the indoor heat exchanger 6, so that the indoor fan 8 is adjusted.

(5) Next, a fifth embodiment will be described.

FIG. 6 shows a refrigeration cycle of the fifth embodiment. In the fifth embodiment, a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, a connection pipe 5, and an indoor heat exchanger 6 are sequentially connected. Then, an outdoor temperature sensor 21 for measuring pipe temperature is attached to an outlet of the outdoor heat exchanger 3, and an indoor temperature sensor 22 is attached to an outlet of the indoor heat exchanger 6.

During cooling, the refrigerant is condensed by the outdoor heat exchanger 3 and exits from the heat exchanger outlet. The heat exchanger outlet temperature at that time is a condensing temperature corresponding to the condensing pressure. Here, since the condensing pressure is almost the same as the compressor discharge pressure, the compressor discharge pressure can be estimated from the outdoor heat exchanger outlet temperature.

Further, during heating, since the refrigerant is condensed in the indoor heat exchanger 6, the compressor discharge pressure can be estimated from the indoor heat exchanger outlet temperature.

Here, the design pressure of the piping (3.16 MPa)
From this, the condensation temperature of R410A is determined to be 51.5 ° C.

Next, the control configuration of the fifth embodiment is shown in FIG. A main controller 12 is connected to a commercial power supply 10 via a power switch 11. The main control unit 12 has a remote control 2 for operation setting.
3, the expansion valve control unit 13, the compressor control unit 14, the indoor fan control unit 15, the outdoor fan control unit 16, the outdoor temperature sensor 21, and the indoor temperature sensor 22 are connected.

The control during cooling in the fifth embodiment will be described below.

The main control unit 12 always controls the outdoor temperature sensor 2
1 is detected.

When the temperature of the outdoor temperature sensor 21 reaches 51.5 ° C., the main controller 12 sets the discharge pressure to 3.16 MPa.
Is reached, and a command is issued to the expansion valve control unit 13 to open the expansion valve 4.

The expansion valve controller 13 opens the opening of the expansion valve 4.

Since the throttle was opened, the discharge pressure decreased,
The heat exchanger outlet temperature also decreases.

When the discharge pressure becomes 3.16 MPa or less, the heat exchanger outlet temperature also becomes 51.5 ° C. or less.

The main controller 12 determines from the value of the temperature sensor 21 that the discharge pressure has become equal to or less than 3.16 MPa.
A command is issued to the expansion valve controller 13 so that normal control is performed.

When the temperature sensor detects 51.5 ° C. again, the following control is performed.

It can be seen from the above control that the discharge pressure is limited below the design pressure of the piping. Therefore, since the refrigeration cycle of the fifth embodiment functions at or below the design pressure of the piping, the connection piping for R22 can be used.

At the time of heating, the value of the indoor temperature sensor may be detected in.

Although the figure shows cooling, heating is also effective.

[0079]

According to the present invention, in the air conditioner using R410A, the discharge pressure of the compressor can be limited to the design pressure of the pipe or less, so that the connection of R22 can be performed without using the connection pipe corresponding to R410A. An air conditioner that can use piping can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a general air conditioner.

FIG. 2 is a diagram illustrating an air conditioner according to a first embodiment.

FIG. 3 is a diagram illustrating a control configuration according to the first embodiment.

FIG. 4 is a diagram illustrating an air conditioner according to a third embodiment.

FIG. 5 is a diagram illustrating a control configuration according to a third embodiment.

FIG. 6 is a diagram illustrating an air conditioner according to a fifth embodiment.

FIG. 7 is a diagram illustrating a control configuration according to a fifth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... 4-way valve, 3 ... Outdoor heat exchanger, 4 ... Expansion valve, 5 ... Connection piping, 6 ... Indoor heat exchanger, 7 ... Outdoor fan, 8 ... Indoor fan, 9 ... Pressure switch, 10 ... Commercial power supply, 11 ... Power switch, 12 ... Main control unit, 13 ... Expansion valve control unit, 14 ... Compressor control unit, 15 ... Indoor fan control unit, 16 ... Outdoor fan control unit, 17 ... Bypass pipe a, 1
8: bypass pipe b, 19: two-way valve, 20: two-way valve control unit, 21: outdoor temperature sensor, 22: indoor temperature sensor, 2
3. Remote control.

Claims (6)

[Claims] An outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger, an expansion device, and a fan for outdoor heat exchange in a single box, and an indoor heat exchanger and a fan for indoor heat exchange. In the air conditioner that constitutes a refrigeration cycle by connecting the indoor unit and the outdoor unit with a connection pipe, using a refrigerant R410A, installing a pressure sensing device, and setting An air conditioner characterized in that, when the pressure reaches a pressure, the discharge pressure is reduced by using pressure limiting means, and operation can be performed at an arbitrary pressure or lower. 2. The pressure sensing device according to claim 1, wherein a pressure switch, a pressure sensor, or a combination thereof is used as the pressure sensing device. An air conditioner characterized by being able to operate at an arbitrary pressure or lower by reducing the discharge pressure by using machine speed control, increasing / decreasing the air volume of an indoor / outdoor heat exchanger, or a combination thereof. 3. A pressure sensor according to claim 1, wherein the temperature sensor detects a compressor discharge temperature, an outlet temperature of a heat exchanger in which a refrigerant condenses, or a temperature of a combination thereof. When the estimated predetermined pressure is reached, the pressure limiting means may be a throttle device opening control, a compressor rotation speed control, an air flow increase / decrease of an indoor / outdoor heat exchanger, a bypass of a compressor discharge pipe and a suction pipe, or any of them. An air conditioner characterized in that the discharge pressure is reduced by using a combination of the above, and the operation can be performed at an arbitrary limited pressure or less. 4. The squeezing device according to claim 1, wherein
The discharge pressure is reduced by using expansion valve opening control, compressor rotation speed control, airflow increase / decrease of indoor / outdoor heat exchangers, or a combination of these, and operation can be performed at an arbitrary pressure or lower. Air conditioner. 5. An air conditioner according to claim 2, wherein the arbitrary limiting pressure is 3.16 MPa or less. 6. The method according to claim 3, wherein the temperature of the outlet pipe of the outdoor heat exchanger during cooling is detected, and the temperature of the outlet pipe of the indoor heat exchanger is detected during heating, and the detected temperature is 51.5 ° C. An air conditioner characterized by the following.