JP2001330309A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger for an air conditioner wherein the amount of dehumidification upon dehumidification operation is increased while suppressing deterioration of performance upon cooling operation and heating operation. SOLUTION: In an indoor heat exchanger having a structure where it is divided into a refrigerant upstream side heat exchanger and a refrigerant downstream side heat exchanger with a two-way valve, which includes a pressure reduction mechanism with respect to the flow of a refrigerant upon dehumidifying operation, taken as a boundary, a fin pitch of a fin group of the refrigerant downstream side heat exchanger is more narrowed than that of a fin group of the refrigerant upstream side heat exchanger to increase a heat transfer area of the refrigerant downstream side heat exchanger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an air conditioner having a dehumidifying operation function.

[0002]

2. Description of the Related Art An air conditioner has been used throughout the year by having a dehumidifying operation in addition to a cooling operation and a heating operation.

[0003] Although this air conditioner is a dehumidifying operation, it removes the humidity of indoor air by a cooling operation, so that the indoor temperature decreases. Therefore, as a dehumidifying operation that does not lower the indoor temperature, a weak cooling operation in which the fan in the indoor unit is rotated at a low speed is performed, and the temperature of the air blown from the indoor unit is increased by heating the dehumidified air with an electric heater. There is something that I did.

Further, the heat exchanger in the indoor unit is divided into an evaporator and a condenser, and a throttle valve is provided between the divided heat exchangers so as to act on the evaporator and the condenser. By heating the dehumidified air from the heat of the condenser,
In some cases, the temperature of air blown from an indoor unit is increased.

In the dehumidifying operation, the latter type of dehumidifying method, which has a high power saving effect, has recently attracted attention. As a conventional technique of the dehumidifying operation, for example, there is Japanese Patent Application Laid-Open No. 9-287770.

[0006]

As described above, various studies have been made on air conditioners in order to save power. As a means of saving power, for example, there is a method of increasing the size of an indoor heat exchanger or rotating an indoor fan at a high speed to increase the air volume in order to improve the heat exchange efficiency.

Of these means, when the indoor fan is rotated at a high speed, the evaporation pressure in the indoor heat exchanger is increased, and the evaporation of the refrigerant is accelerated and the compression work of the compressor is reduced. , Leading to power saving.

However, when the evaporation of the indoor heat exchanger is accelerated, the refrigerant is completely evaporated on the upstream side of the refrigerant in the indoor heat exchanger, and the evaporation is stopped by the shortage of the liquid refrigerant on the downstream side of the refrigerant. There is a possibility that the dehumidification effect may be reduced due to the increase in the temperature.

An object of the present invention is to provide an air conditioner in which power consumption is suppressed and dehumidification is increased.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner in which a heat exchanger comprising a plurality of fins and a refrigerant pipe is provided at a position facing a suction port provided on a front surface and an upper surface in an indoor unit. In this case, the fin pitch of the heat exchanger facing the suction port of the front surface is made smaller than the fin pitch of the heat exchanger facing the upper surface.

Further, in an air conditioner provided with a heat exchanger comprising a plurality of fins and a refrigerant pipe at a position facing a suction port provided at a front portion and an upper portion in an indoor unit, the suction port of the front portion is provided. This is achieved by providing a cut-and-finished portion on the fin of the heat exchanger facing the above.

[0012] It is also achieved by making the diameter of the refrigerant pipe of the heat exchanger facing the suction port of the front part larger than the diameter of the refrigerant pipe of the heat exchanger facing the upper part.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of a refrigeration cycle. FIG. 2 is a perspective view of the indoor heat exchanger.

In FIG. 1, reference numeral 1 denotes a refrigeration cycle including an indoor unit and an outdoor unit of an air conditioner. Reference numeral 2 denotes a compressor, which is a scroll compressor or a rotary compressor. Reference numeral 3 denotes a four-way valve for switching the direction of circulation of the refrigerant in accordance with a cooling operation or a heating operation command requested by the user. 4 is an outdoor heat exchanger.
Reference numeral 5 denotes a fan for blowing outdoor air to the outdoor heat exchanger 4 to exchange heat. Reference numeral 6 denotes an expansion device that changes the amount of expansion according to the cooling and heating operation modes.

Reference numeral 7 denotes an indoor heat exchanger divided into two or three. In the cooling operation or the dehumidifying operation, the heat exchanger 7 has a refrigerant upstream heat exchanger 7a and a refrigerant downstream heat exchanger 7b. In the case of the heating operation, 7a is a refrigerant downstream heat exchanger, and 7b is a refrigerant upstream heat exchanger. Numeral 8 is a two-way valve provided between the refrigerant upstream heat exchanger 7a and the refrigerant downstream heat exchanger and provided with a pressure reducing mechanism. These components are connected by a refrigerant pipe 9 to form a series of refrigeration cycles. Reference numeral 10 denotes a fan for sucking indoor air into the indoor heat exchanger 7, exchanging heat with the indoor air, and discharging the conditioned air generated by the heat exchange into the room.

In FIG. 2, A indicates the flow direction of the refrigerant when the dehumidifying operation is performed. The indoor heat exchanger 7 is separated from a refrigerant upstream heat exchanger 7a by a two-way valve 8 having a pressure reducing mechanism.
And a refrigerant downstream heat exchanger 7b.

The refrigerant upstream heat exchanger 7a includes a fin group 11a stacked at a narrow interval from each other and a fin group 1a.
1a, and a group of pipes 12a penetrating the pipe 1a orthogonally.

Similarly, the refrigerant downstream heat exchanger 7b is composed of a fin group 11b stacked at a narrow interval from each other and a pipe group 12b penetrating the fin group 11b orthogonally.

Reference numeral 13a denotes a refrigerant inlet of the refrigerant upstream heat exchanger 7a. 13b is a refrigerant inlet side pipe of the refrigerant downstream heat exchanger 7b, and 13c is a refrigerant outlet side pipe. The fin group 11b of the refrigerant downstream heat exchanger 7b has a fin pitch of the fin group 1 of the refrigerant upstream heat exchanger 7a.
It is set smaller than the fin pitch of 1a.

The state of refrigerant flow during the dehumidifying operation in the indoor heat exchanger 7 will be described. First, a high-temperature and high-pressure gas refrigerant is discharged from the compressor 2 shown in FIG. 1 and flows into the outdoor heat exchanger 4 via the four-way valve 3. The number of rotations of the outdoor fan 5 provided in the outdoor unit is controlled according to the temperature and humidity of the room in which the indoor unit is installed, and the heat exchange amount of the outdoor heat exchanger 4 is adjusted. The refrigerant in the outdoor heat exchanger 4 condenses and flows into the expansion valve 6. Since the expansion device 6 is in the fully opened state or almost fully opened state, it flows directly into the refrigerant upstream heat exchanger 7a of the indoor heat exchanger 7 via the refrigerant pipe 9 without being decompressed. It condenses also in the side heat exchanger 7a and emits high temperature.

At room temperature, which has flowed out of the refrigerant upstream heat exchanger 7a,
The high-pressure refrigerant flows into a two-way valve 8 provided with a pressure reducing mechanism.
The refrigerant is throttled by the two-way valve 8 and decompressed, and becomes a low-temperature and low-pressure refrigerant. Next, the low-temperature and low-pressure refrigerant flows into the refrigerant downstream heat exchanger 7b, thereby absorbing the indoor temperature and changing into a gas, exchanging heat with indoor air,
The moisture in the indoor air is attached to the refrigerant downstream heat exchanger 7b as dew. The refrigerant flowing out of the refrigerant downstream heat exchanger 7 b returns to the inside of the compressor 2 via the four-way valve 3.

As described above, during the dehumidifying operation, the upstream heat exchanger 7a of the refrigerant is used as a part of the condenser, and the downstream heat exchanger 3b of the refrigerant is operated as an evaporator, thereby providing the upstream heat exchanger of the refrigerant. The cooling air cooled in 7a and the high-temperature air due to the condensation heat of the refrigerant downstream heat exchanger 7b are mixed, and the high-temperature dehumidified air is discharged into the room.

In the indoor heat exchanger 7 having this configuration, the fin pitch of the fin group 11b of the refrigerant downstream heat exchanger 7b is made smaller than the fin pitch of the fin group 11a of the refrigerant upstream heat exchanger 7a. The heat transfer area of the heat exchanger 7b is increased.

At this time, in a normal refrigeration cycle, when the heat transfer area of the indoor heat exchanger is increased or the indoor fan is rotated at a high speed, the evaporation pressure increases, the evaporation of the refrigerant is accelerated, and the shortage of the liquid refrigerant is caused. A decrease in the amount of dehumidification due to an increase in temperature may occur.

However, in the refrigeration cycle having the above structure, the evaporation pressure and the condensing pressure become equal by adjusting the throttle amount of the two-way valve 2. Therefore, the work of the compressor is suppressed, the input can be reduced, and the heat transfer area of the downstream heat exchanger 7b is increased, so that the performance of the evaporator is improved and the amount of dehumidification is increased. Can be done.

Further, in the indoor heat exchanger 7, only the fins of the refrigerant downstream heat exchanger 7b have a narrow fin pitch, so that the air volume at the same fan rotation speed during the cooling operation or the heating operation is reduced. It is possible to suppress the deterioration of the cooling performance and the heating performance as much as possible.

The dehumidifying operation is not necessarily performed only by the cooling operation, but can be performed by the heating operation. Therefore, the dehumidifying operation by the heating operation will be described with reference to FIG.

FIG. 3 is the same as FIG. 1 except that the refrigerant circulation path of the refrigeration cycle shown in FIG. 1 is changed to the heating operation.

In the heating operation shown in FIG. 3, 7b is a refrigerant upstream heat exchanger, and 7a is a refrigerant downstream heat exchanger.

A high-temperature and high-pressure gas refrigerant is discharged from the compressor 2 and flows into the indoor heat exchanger 7 via the four-way valve 3.
The refrigerant flows into the refrigerant upstream heat exchanger 7b of the indoor heat exchanger 7 and condenses to generate a high temperature. The normal-temperature and low-pressure refrigerant flowing out of the refrigerant upstream-side heat exchanger 7b flows into the two-way valve 8 provided with a pressure reducing mechanism, is throttled, and has a low temperature and low pressure. Next, low temperature
The low-pressure refrigerant vaporizes in the refrigerant downstream heat exchanger 7a by flowing into the refrigerant downstream heat exchanger 7a, and at the same time absorbs indoor air and becomes an evaporator to exchange heat with indoor air. Dehumidifies to dew point temperature.

Next, the refrigerant flows into the expansion device 6,
At this time, since the expansion device 6 is in a fully opened state or a state in which it is almost fully opened, it flows into the outdoor heat exchanger 4 as it is to evaporate. The refrigerant flowing out of the outdoor heat exchanger 4 returns into the compressor 2 via the four-way valve 3.

As described above, even in the heating operation, the cooling air dehumidified in the refrigerant downstream heat exchanger 7a and the high-temperature air condensed in the refrigerant upstream heat exchange 7b are mixed and discharged into the room. The indoor temperature can be prevented from being lowered by the dehumidifying operation.

The dehumidifying operation by the heating operation is suitable for use in an area where the amount of snowfall is large. In other words, when dehumidification is required in a house covered with high-humidity snow, it becomes cold unless the reheating temperature is raised. Therefore, in the present invention, the fin pitch of the refrigerant upstream heat exchanger 7b is changed to the refrigerant downstream side. Heat exchanger 7
Since the heat radiation area is increased by making the fin pitch narrower than the fin pitch of a, the reheating temperature increases, and it is possible to suppress a decrease in the heating effect.

Further, since the condensing pressure and the condensing pressure are balanced, the work of the compressor is reduced, the input of the compressor is reduced, and the power can be saved.

Next, the fin shape of the indoor heat exchanger according to the present invention is shown in FIGS. 4 (A) and 4 (B).

In FIG. 4A, the fin 11 is provided with cut-and-raised portions 14a to 14i. Of the cut-and-raised portions 14a to 14i, the cut-and-raised portions 14a,
The cut-and-raised portions 14b, 14d, 14f and 14h are arranged in the cut-and-raised directions of 14c, 14e, 14g and 14i.
It is cut and raised in the opposite direction.

In FIG. 4B, the fin 11 is provided with cut-and-raised portions 14a to 14e. The cut-and-raised portions 14a to 14e are all raised in the same direction with respect to the fin plate thickness direction. Therefore, comparing the fin 11 of FIG. 4 (A) with the fin 11 of FIG. 2 (B), the fin 11 cut and raised in both directions has a higher ventilation resistance, but heat transfer due to disturbance of the air flow. High performance.

As shown in FIG. 4 (A), the fins 11 whose cut-off portions are cut and raised in both directions of the fin surface are used for the refrigerant downstream heat exchanger 7b on the evaporator side during the dehumidifying operation. Thus, the heat exchange performance of the evaporator can be promoted, and the amount of dehumidification can be increased. In addition, by using the fins 11 whose cut-off portions are cut and raised only on one side surface for the refrigerant upstream heat exchanger 7a, it is possible to suppress a decrease in the air volume during the cooling operation or the heating operation, and to improve the cooling performance and the like. A decrease in heating performance can be suppressed.

FIG. 5 is a block diagram of an indoor heat exchanger showing another embodiment according to the present invention.

In FIG. 5, the indoor heat exchanger 7 has a two-way valve 1 equipped with a pressure reducing mechanism for the refrigerant flow A during the dehumidifying operation.
At 0, the refrigerant is divided into a refrigerant upstream heat exchanger 7a and a refrigerant downstream heat exchanger 7b. This refrigerant upstream heat exchanger 7a
Is composed of a group of fins 11a stacked at a narrow interval from each other, and a group of pipes 12a penetrating them at right angles. The refrigerant downstream heat exchanger 7b includes a group of fins 11b stacked at a narrow interval from each other. It is composed of a group of large diameter pipes 12b that penetrate them orthogonally.

In the refrigerant downstream heat exchanger 7b of the indoor heat exchanger 7, the inner diameter of the pipe group 12b is made larger than the inner diameter of the pipe group 11a of the refrigerant upstream heat exchanger 7a. Pressure loss of the refrigerant flowing through the refrigerant downstream heat exchanger 7b acting as a heat exchanger can be reduced. At this time, by adjusting the throttle amount of the two-way valve 2 so that the refrigerant pressure at the refrigerant outlet pipe 15 at the time of the dehumidifying operation becomes equal to that before using the large diameter pipe group 12b,
The average evaporation temperature of the refrigerant downstream heat exchanger can be reduced, and the amount of dehumidification can be increased.

As described above, in the indoor heat exchanger of the air conditioner according to the present invention, the heat transfer performance of the evaporator is reduced by reducing the fin pitch of the heat exchanger in the portion that becomes the evaporator during the dehumidifying operation. And the amount of dehumidification can be improved.

Further, since the fin pitch is narrowed only in a part of the indoor heat exchanger, it is possible to suppress a decrease in the air volume at the same fan rotation speed during the cooling operation or the heating operation, and the cooling performance and the heating performance are reduced. Can be suppressed.

Further, by using fins having good heat transfer performance for the portion of the indoor heat exchanger which becomes the evaporator during the dehumidification operation, the heat transfer performance of the evaporator can be improved, and the amount of dehumidification can be improved. Can be improved.

Further, by using a large-diameter pipe as a heat exchanger pipe in a portion which becomes an evaporator during the dehumidifying operation, it is possible to reduce the pressure loss of the refrigerant flowing through the heat exchanger acting as the evaporator during the dehumidifying operation. As a result, the average evaporating temperature of the entire evaporator can be lowered, so that the dehumidification amount can be increased.

[0046]

According to the present invention, it is possible to provide an air conditioner with reduced power consumption and increased dehumidification amount.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram when a cooling operation is performed by an air conditioner equipped with the present invention.

FIG. 2 is a perspective view of an indoor heat exchanger provided with the present invention.

FIG. 3 is a refrigeration cycle diagram when a heating operation is performed by an air conditioner equipped with the present invention.

FIG. 4 is a diagram showing the shape of a fin in an indoor heat exchanger provided with the present invention.

FIG. 5 is a configuration diagram of an indoor heat exchanger showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Refrigeration cycle, 2 ... Compressor, 3 ... Four-way valve, 4 ... Outdoor heat exchanger, 5 ... Outdoor fan, 6 ... Refrigerator expansion device, 7 ... Indoor heat exchanger, 8 ... Two-way valve, 9 ... Refrigerant piping 10, indoor fan, 11 fin, 12 pipe.

Claims (3)

[Claims] 1. An air conditioner provided with a heat exchanger comprising a plurality of fins and a refrigerant pipe at a position facing a suction port provided at a front part and an upper part in an indoor unit, wherein the suction port at the front part is provided. An air conditioner in which the fin pitch of the heat exchanger facing the upper surface is smaller than the fin pitch of the heat exchanger facing the upper surface. 2. An air conditioner provided with a heat exchanger comprising a plurality of fins and a refrigerant pipe at a position facing a suction port provided at a front part and an upper part in an indoor unit, wherein the suction port at the front part is provided. An air conditioner that has a fin of a heat exchanger opposite to the fin and a cut-off portion. 3. An air conditioner wherein a diameter of a refrigerant pipe of a heat exchanger facing the suction port of the front part is larger than a diameter of a refrigerant pipe of the heat exchanger facing the upper part.