JPH08136077A - Heat pump type air conditioner - Google Patents

Abstract

PURPOSE: To operate an optimum refrigerating cycle by suitably holding a pressure reduced amount for the changes of operating conditions and the length of a refrigerant tube for coupling an outdoor unit to an indoor unit and to apply in the case of a plurality of indoor units. CONSTITUTION: A heat pump type air conditioner comprises an outdoor expansion valve Exp1 installed in an outdoor unit A', a first differential pressure detector Dp1 for detecting the refrigerant pressure difference between the inlet and the outlet sides of the valve Exp1, and an outdoor expansion valve controller Cnt1 for controlling the opening of the valve Exp1 so that the refrigerant pressure difference by the detector Dp1 falls within a predetermined range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle control during cooling / heating operation in a heat pump type air conditioner using air as a heat source.

[0002]

2. Description of the Related Art For heat pump type air conditioners,
Various developments have already been made.
There is a heat pump type air conditioner as disclosed in Japanese Patent Laid-Open No. 2-158958.

The basic technique will be described below. As shown in FIG. 5, the conventional heat pump type air conditioner includes an outdoor unit A and an indoor unit B.

The outdoor unit A includes a compressor 1, a four-way valve 2,
Outdoor heat exchanger 3, first pressure reducing capillary tube 4a, first check valve 7
a, an accumulator 6, and the indoor unit B is composed of an indoor heat exchanger 5, a second pressure reducing capillary tube 4b, and a second check valve 7b.

The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the first pressure reducing capillary 4a, the second pressure reducing capillary 4a,
The indoor heat exchanger 5 and the accumulator 6 are sequentially connected in an annular shape by a refrigerant pipe to form a refrigeration cycle.

The operation of the heat pump type air conditioner configured as described above will be described.

First, in the cooling operation, the four-way valve 2 is switched to the cooling circuit, the refrigerant flows in the direction of the solid line arrow in the figure to form the cooling cycle, and the outdoor heat exchanger 3 is connected to the condenser and the indoor heat exchange. The vessel 5 acts as an evaporator.

In the cooling cycle, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the outdoor heat exchanger 3 to become a high-temperature and high-pressure liquid refrigerant, which is decompressed and expanded by the first pressure-reducing capillary tube 4a to form a two-phase. It becomes a refrigerant and exits the outdoor unit A,
After that, the cycle in which the refrigerant flows into the indoor unit B while further decompressing and expanding due to the resistance in the refrigerant piping and evaporating in the indoor heat exchanger 5 to absorb heat from the indoor air (cooling operation) is repeated.

On the other hand, in the heating operation, the four-way valve 2 is switched to the heating circuit, the refrigerant flows in the direction of the broken line arrow in the figure to form the heating cycle, and the indoor heat exchanger 5 is replaced with the condenser and the outdoor heat exchanger. The vessel 3 acts as an evaporator.

In the heating cycle, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the indoor heat exchanger 5 to radiate heat to indoor air (heating operation) to become a high-temperature and high-pressure liquid refrigerant. The decompression capillary 4b decompresses and expands to become a two-phase refrigerant, which leaves the indoor unit B and then further decompresses and expands due to internal resistance in the refrigerant pipe, and then flows into the outdoor unit A, where the outdoor heat exchanger 3 The cycle of evaporation is repeated.

In the heat pump type air conditioner as described above, since the refrigerant flowing in the two refrigerant pipes connecting the outdoor unit A and the indoor unit B can be a gas refrigerant and a two-phase refrigerant, the specific weight of the refrigerant is Is small, the amount of refrigerant required for the refrigeration cycle is small, and no additional refrigerant is required even when the pipe length is long.

[0012]

However, in the above-mentioned conventional configuration, since the capillaries 4a and 4b are used as the decompression device for both the cooling and heating operations, the decompression amount is fixed, so that the operating condition is reduced. Depending on the length of the refrigerant pipe connecting the outdoor unit A and the indoor unit B, the decompression amount may become excessively large or excessively small, and the refrigeration cycle may not be operated in an optimum state.
It has a drawback that it cannot be applied when a plurality of indoor units are installed with respect to the table.

Therefore, the present invention solves the conventional problems, and an optimum refrigeration cycle is obtained by appropriately maintaining the pressure reduction amount with respect to changes in operating conditions and the length of the refrigerant pipe connecting the outdoor unit and the indoor unit. It is an object of the present invention to provide a heat pump type air conditioner that can be operated in a room and can be applied to a case of a plurality of indoor units.

[0014]

The technical means of the present invention for achieving the above object is to install an outdoor expansion valve in an outdoor unit, and to adjust the refrigerant pressure difference between the inlet side and the outlet side of the outdoor expansion valve. A first differential pressure detection device for detecting, and an outdoor expansion valve control device for controlling the opening of the outdoor expansion valve so that the refrigerant pressure difference by the first differential pressure detection device falls within a predetermined range during cooling operation. Is.

Further, instead of the first differential pressure calculating device, a first differential pressure calculating device for calculating the refrigerant pressure difference between the inlet side and the outlet side of the outdoor expansion valve from the refrigerant temperature at the inlet side and the outlet side of the outdoor expansion valve is provided. The outdoor expansion valve control device is provided to control the opening of the outdoor expansion valve so that the refrigerant pressure difference by the first differential pressure calculation device falls within a predetermined range during the cooling operation.

Also, a second differential pressure detecting device, which is provided with an indoor expansion valve in the indoor unit and detects a refrigerant pressure difference between the inlet side and the outlet side of the indoor expansion valve, and the second differential pressure detection during heating operation. An indoor expansion valve control device that controls the opening degree of the indoor expansion valve so that the refrigerant pressure difference due to the device falls within a predetermined range.

Further, instead of the second differential pressure calculating device, there is provided a second differential pressure calculating device for calculating the refrigerant pressure difference between the inlet side and the outlet side of the indoor expansion valve from the refrigerant temperature at the inlet side and the outlet side of the indoor expansion valve. The indoor expansion valve control device is provided to control the opening of the indoor expansion valve so that the refrigerant pressure difference by the second differential pressure calculation device falls within a predetermined range during the heating operation.

[0018]

According to the heat pump type air conditioner of the present invention, in the cooling operation, the pressure reduction amount in the outdoor expansion valve is controlled by the first differential pressure detecting device or the first differential pressure calculating device at the inlet of the outdoor expansion valve. It can be detected by the refrigerant pressure difference between the side and the outlet side, and the opening degree of the outdoor expansion valve can be arbitrarily controlled so that the refrigerant pressure difference falls within a predetermined range.

As a result, by properly maintaining the decompression amount by the outdoor expansion valve in response to changes in operating conditions and the length of the refrigerant pipe connecting the outdoor unit and the indoor unit, the indoor expansion valve can be used in the indoor heat exchanger. The evaporation pressure can be controlled appropriately, and it can be applied even when a plurality of indoor units are installed.

Further, in the heating operation, the pressure reduction amount in the indoor expansion valve is detected by the refrigerant pressure difference between the inlet side and the outlet side of the indoor expansion valve by the second differential pressure detecting device or the second differential pressure calculating device. Therefore, the opening degree of the indoor expansion valve can be arbitrarily controlled so that the refrigerant pressure difference falls within a predetermined range.

As a result, by appropriately maintaining the decompression amount by the indoor expansion valve in response to changes in operating conditions and the length of the refrigerant pipe connecting the outdoor unit and the indoor unit, the outdoor heat exchanger can be used in the outdoor heat exchanger. The evaporation pressure can be controlled appropriately, and it can be applied even when a plurality of indoor units are installed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a heat pump type air conditioner according to the present invention will be described below with reference to the drawings. The same components as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a refrigeration cycle diagram of the heat pump type air conditioner of the first embodiment of the present invention.

In FIG. 1, the heat pump type air conditioner comprises an outdoor unit A'and an indoor unit B '.

The outdoor unit A'detects the refrigerant pressure difference ΔP1 between the inlet side and the outlet side of the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the outdoor expansion valve Exp1, the accumulator 6, and the outdoor expansion valve Exp1. A first differential pressure detection device Dp1 and an outdoor expansion valve control device Cnt1 that controls the opening of the outdoor expansion valve Exp1 so that the refrigerant pressure difference by the first differential pressure detection device Dp1 falls within a predetermined range during cooling operation. ing.

The indoor unit B'includes an indoor heat exchanger 5 and an indoor flow valve Exp2.

The operation of the heat pump type air conditioner configured as described above will be described below.

In the case of the cooling operation, the four-way valve 2 is switched to the cooling circuit, the refrigerant flows in the direction of the solid line arrow in the figure to form the cooling cycle, and the outdoor heat exchanger 3 is connected to the condenser,
The indoor heat exchanger 5 acts as an evaporator.

In the cooling cycle, the high-temperature and high-pressure gas refrigerant leaving the compressor 1 is condensed in the outdoor heat exchanger 3 to become a high-temperature and high-pressure liquid refrigerant, which is decompressed and expanded by the outdoor expansion valve Exp1 to form a two-phase refrigerant. Become.

Thereafter, the outdoor unit A'is exited, and thereafter, while being further decompressed and expanded by the internal resistance in the refrigerant pipe, it flows into the indoor unit B'and evaporated in the indoor heat exchanger 5 to absorb heat from the indoor air. (Cooling operation).

At this time, even if a plurality of indoor units B'are installed, in order to enable the capacity control in each indoor unit B ', the indoor expansion valve Exp2 in the indoor unit B'is provided.
It is necessary that the pressure of the refrigerant flowing into is within the pressure reducing performance range of the indoor expansion valve Exp2.

Therefore, the first differential pressure detection device Dp1 detects the refrigerant pressure difference ΔP1 between the inlet side and the outlet side of the outdoor expansion valve Exp1 and the outdoor expansion is performed so that the refrigerant pressure difference ΔP1 falls within a predetermined range. The opening degree of the valve Exp1 is controlled by the outdoor expansion valve control device Cnt1.

Therefore, regardless of the length of the refrigerant pipe between the outdoor unit A'and the indoor unit B ', the indoor unit B'is
Since the refrigerant pressure flowing into the indoor expansion valve Exp2 therein is within the decompression performance range of the indoor expansion valve Exp2, the indoor expansion valve Exp2 can optimally control the cooling capacity of the indoor unit.

As described above, the heat pump type air conditioner of this embodiment has the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the outdoor expansion valve Exp1, the accumulator 6, and the outdoor expansion valve E.
The first differential pressure detection device Dp1 that detects the refrigerant pressure difference ΔP1 between the inlet side and the outlet side of xp1 and the outdoor expansion valve so that the refrigerant pressure difference by the first differential pressure detection device Dp1 during cooling operation falls within a predetermined range. Since the outdoor unit A'composed of the outdoor expansion valve control device Cnt1 for controlling the opening degree of the Exp1 and the indoor unit B'composed of the indoor heat exchanger 5 and the indoor flow rate valve Exp2 are constituted, And the amount of decompression by the outdoor expansion valve is properly maintained against changes in the length of the refrigerant pipe connecting the outdoor unit and the indoor unit, so that the evaporation pressure in the indoor heat exchanger is appropriately controlled by the indoor expansion valve. It is also possible to apply when installing a plurality of indoor units.

Next, a second embodiment of the heat pump type air conditioner according to the present invention will be described with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 2 shows the refrigeration cycle of the heat pump type air conditioner of the second embodiment. As shown in FIG. 2, in the present embodiment, the outdoor expansion valve Ex in the outdoor unit A ′ is
The first differential pressure detection device Dp is provided on the inlet side and the outlet side of p1.
Instead of 1, the first temperature sensor T for detecting the temperature of the refrigerant
The refrigerant saturation pressure Ps and the refrigerant pressure difference ΔP1 between the refrigerant temperature h1 and the second temperature sensor Th2, the first temperature sensor Th1 and the second temperature sensor Th2 are calculated from the refrigerant temperatures to the outdoor expansion valve control device Cnt1. The first differential pressure calculating device Cal1 for outputting is installed, and in this case, the same effect as that of the first embodiment can be obtained.

That is, since the refrigerant on the inlet side and the outlet side of the outdoor expansion valve Exp1 is in a two-phase state, the refrigerant pressure can be detected by detecting the temperature and calculating the refrigerant saturation pressure Ps. .

Next, a third embodiment of the heat pump type air conditioner according to the present invention will be described with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 3 is a refrigeration cycle diagram of the heat pump type air conditioner of the third embodiment of the present invention.

In FIG. 3, the heat pump type air conditioner comprises an outdoor unit A'and an indoor unit B ".

The outdoor unit B "includes the indoor heat exchanger 5, the indoor expansion valve Exp2, and the second differential pressure detecting device Dp for detecting the refrigerant pressure difference ΔP2 between the inlet side and the outlet side of the indoor expansion valve Exp2.
2 and the indoor expansion valve Exp2 so that the refrigerant pressure difference by the second differential pressure detection device Dp2 during the heating operation falls within a predetermined range.
The indoor expansion valve control device Cnt2 for controlling the opening degree of Cnt2.

The operation of the heat pump type air conditioner constructed as above will be described below.

In the heating operation, the four-way valve 2 is switched to the heating circuit, the refrigerant flows in the direction of the broken line arrow in the drawing to form the heating cycle, and the indoor heat exchanger 5 is connected to the condenser.
The outdoor heat exchanger 3 acts as an evaporator.

In the above heating cycle, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is condensed in the indoor heat exchanger 5 to radiate heat to the indoor air (heating operation) to become a high-temperature and high-pressure liquid refrigerant, and expand indoors. It is decompressed and expanded by the valve Exp2 to become a two-phase refrigerant.

After that, the indoor unit B ″ is discharged, and thereafter, while being further decompressed and expanded by the internal resistance in the refrigerant pipe, the refrigerant flows into the outdoor unit A ′ and evaporates in the outdoor heat exchanger 3 to absorb heat from the outdoor air. To do.

At this time, even when a plurality of indoor units B ″ are installed, in order to enable the capacity control in each indoor unit B ″, the outdoor expansion valve Exp1 in the outdoor unit A ′ is provided.
The pressure of the refrigerant flowing into the outdoor expansion valve Exp1 needs to be within the pressure reducing performance range.

Therefore, the second differential pressure detecting device Dp2 detects the refrigerant pressure difference ΔP2 between the inlet side and the outlet side of the indoor expansion valve Exp2 and the indoor expansion is performed so that the refrigerant pressure difference ΔP2 falls within a predetermined range. The opening degree of the valve Exp2 is controlled by the indoor expansion valve control device Cnt2.

Therefore, regardless of the length of the refrigerant pipe between the outdoor unit A'and the indoor unit B ", the outdoor unit A '
Since the pressure of the refrigerant flowing into the outdoor expansion valve Exp1 therein is within the pressure reducing performance range of the outdoor expansion valve Exp1, it is possible to optimally control the evaporation capacity of the outdoor unit by the outdoor expansion valve Exp1.

As described above, in the heat pump type air conditioner of the present embodiment, the outdoor unit A ', the indoor heat exchanger 5, the indoor expansion valve Exp2, and the refrigerant pressure difference Δ between the inlet side and the outlet side of the indoor expansion valve Exp2. Second differential pressure detection device Dp for detecting P2
2 and the indoor expansion valve Exp2 so that the refrigerant pressure difference by the second differential pressure detection device Dp2 during the heating operation falls within a predetermined range.
The indoor expansion valve control device Cnt2 for controlling the opening degree of the indoor expansion unit B ″ is used, and therefore the outdoor expansion valve is used for the heating operation condition and the change of the refrigerant pipe length connecting the outdoor unit and the indoor unit. By properly holding the decompression amount, the outdoor expansion valve can appropriately control the evaporation pressure in the outdoor heat exchanger, and can also be applied when a plurality of indoor units are installed.

Next, a fourth embodiment of the heat pump type air conditioner according to the present invention will be described with reference to the drawings. The same components as those in the third embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 4 shows a refrigeration cycle of the heat pump type air conditioner of the fourth embodiment. As shown in FIG. 4, in this embodiment, the indoor expansion valve Exp in the indoor unit B ″ is
The second differential pressure detection device Dp2 is provided on the inlet side and the outlet side of
Instead of, a third temperature sensor Th for detecting the refrigerant temperature
The refrigerant saturation pressure Ps and the refrigerant pressure difference ΔP2 between the third and fourth temperature sensors Th4, the third temperature sensor Th3, and the fourth temperature sensor Th4 are calculated from the refrigerant temperatures to the outdoor expansion valve control device Cnt2. The second differential pressure calculation device Cal2 for outputting is installed, and in this case, the same effect as that of the third embodiment can be obtained.

That is, since the refrigerant on the inlet side and the outlet side of the indoor expansion valve Exp2 is in a two-phase state, the refrigerant pressure can be detected by detecting the temperature and calculating the refrigerant saturation pressure Ps. .

[0053]

As described above, according to the present invention, the outdoor expansion valve is installed in the outdoor unit, and the first differential pressure detecting device for detecting the refrigerant pressure difference between the inlet side and the outlet side of the outdoor expansion valve or the outdoor unit. A first differential pressure calculation device that detects a refrigerant pressure difference from the refrigerant temperatures of the inlet side and the outlet side of the expansion valve, and the refrigerant pressure difference between the first differential pressure detection device or the first differential pressure calculation device during cooling operation is predetermined. Since the outdoor expansion valve control device that controls the opening of the outdoor expansion valve so as to be within the range is provided, the outdoor expansion valve control device controls the outdoor operation in response to cooling operation conditions and changes in the refrigerant pipe length that connects the outdoor unit and the indoor unit. By properly holding the amount of pressure reduction by the expansion valve, the indoor expansion valve can properly control the evaporation pressure in the indoor heat exchanger, and it can also be applied when installing multiple indoor units. is there.

A second differential pressure detector for installing an indoor expansion valve in the indoor unit and detecting the refrigerant pressure difference between the inlet side and the outlet side of the indoor expansion valve, or the inlet side and the outlet side of the indoor expansion valve. Second differential pressure calculation device for detecting the refrigerant pressure difference from the refrigerant temperature of the second indoor expansion, and indoor expansion so that the refrigerant pressure difference by the second differential pressure detection device or the second differential pressure calculation device during heating operation falls within a predetermined range. Since the indoor expansion valve control device for controlling the opening degree of the valve is provided, the amount of decompression by the indoor expansion valve can be appropriately adjusted with respect to changes in the heating operation conditions and the length of the refrigerant pipe connecting the outdoor unit and the indoor unit. By holding it, the evaporation pressure in the outdoor heat exchanger can be appropriately controlled by the outdoor expansion valve, and it can be applied even when a plurality of indoor units are installed.

[Brief description of drawings]

FIG. 1 is a first heat pump type air conditioner according to the present invention.
Refrigeration cycle diagram of Example

FIG. 2 is a second heat pump type air conditioner according to the present invention.
Refrigeration cycle diagram of Example

FIG. 3 is a third heat pump type air conditioner according to the present invention.
Refrigeration cycle diagram of Example

FIG. 4 is a fourth heat pump type air conditioner according to the present invention.
Refrigeration cycle diagram of Example

FIG. 5 is a refrigeration cycle diagram of a conventional heat pump type air conditioner.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 5 Indoor expansion valve 6 Accumulator Exp1 Outdoor expansion valve Exp2 Indoor expansion valve Dp1 First differential pressure detection device Dp2 Second differential pressure detection device Cnt1 Outdoor expansion valve control device Cnt2 Indoor expansion valve control Device Th1 1st temperature sensor Th2 2nd temperature sensor Th3 3rd temperature sensor Th4 4th temperature sensor Cal1 1st differential pressure calculation device Cal2 2nd differential pressure calculation device A'outdoor unit B ', B "indoor unit

Claims (4)

[Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger,
An outdoor unit including an outdoor expansion valve, an accumulator, an indoor expansion valve, and an indoor unit including an indoor heat exchanger. The compressor, the four-way valve, the outdoor heat exchanger, the outdoor expansion valve, and the indoor expansion unit. A first differential pressure detection device that detects the refrigerant pressure difference between the inlet side and the outlet side of an outdoor expansion valve in a refrigeration cycle in which a valve, an indoor heat exchanger, and an accumulator are sequentially connected by a refrigerant pipe in an annular shape, and during cooling operation. A heat pump type air conditioner comprising: an outdoor expansion valve control device that controls the opening degree of the outdoor expansion valve so that the refrigerant pressure difference by the first differential pressure detection device falls within a predetermined range. 2. A compressor, a four-way valve, an outdoor heat exchanger,
An outdoor expansion valve, an outdoor unit including an accumulator, an indoor expansion valve, and an indoor unit including an indoor heat exchanger, and a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, and an indoor expansion. A first temperature sensor for detecting the refrigerant temperature at the inlet side and the outlet side of an outdoor expansion valve in a refrigeration cycle in which a valve, an indoor heat exchanger, and an accumulator are sequentially connected in an annular shape by a refrigerant pipe; A first differential pressure calculation device for calculating a refrigerant saturation pressure and a refrigerant pressure difference between the first temperature sensor and the second temperature sensor, and a refrigerant pressure difference calculated by the first differential pressure calculation device during cooling operation. A heat pump type air conditioner including an outdoor expansion valve control device that controls the opening degree of the outdoor expansion valve so that is within a predetermined range. 3. An outdoor unit and an indoor unit, wherein a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, an indoor expansion valve, an indoor heat exchanger, and an accumulator are sequentially connected in a ring by a refrigerant pipe. And a second differential pressure detection device for detecting the refrigerant pressure difference between the inlet side and the outlet side of the indoor expansion valve in the refrigeration cycle, and the refrigerant pressure difference by the second differential pressure detection device during heating operation falls within a predetermined range. The heat pump type air conditioner according to claim 1, further comprising an indoor expansion valve control device for controlling the opening degree of the indoor expansion valve. 4. A third temperature sensor for detecting a refrigerant temperature at an inlet side and an outlet side of an indoor expansion valve in a refrigeration cycle, a fourth temperature sensor, and the third temperature sensor,
And a second differential pressure calculation device for calculating the refrigerant saturation pressure and the refrigerant pressure difference between the two from the refrigerant temperature by the fourth temperature sensor and the refrigerant pressure difference by the second differential pressure calculation device during the heating operation so that they fall within a predetermined range. The heat pump type air conditioner according to claim 1, further comprising: an indoor expansion valve control device that controls an opening degree of the indoor expansion valve.