JPH0914726A - Air conditioner - Google Patents

Abstract

PURPOSE: To provide an air conditioner which can carry out a dehumidifying ' without decreasing an indoor temperature and further a fast dehumidifying can be attained. CONSTITUTION: A degree of opening of an electrical expansion valve 24 is controlled such that refrigerant is evaporated with an auxiliary indoor heat exchanger 7 and the refrigerant shows an super-heating region at a main indoor heat exchanger 8, thereby a dehumidifying operation is performed and at the same time an initial degree of opening of the electrical expansion valve 24 when a dehumidifying operation is started is set to be lower than an initial degree of opening when the cooling operation is started.

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 a dehumidifying operation function.

[0002]

2. Description of the Related Art An air conditioner includes a compressor, an outdoor heat exchanger,
A room can be cooled by providing a refrigeration cycle for sequentially connecting an expansion mechanism and an indoor heat exchanger to circulate a refrigerant, and making the outdoor heat exchanger function as a condenser and the indoor heat exchanger as an evaporator. In addition, with cooling, moisture in the air is condensed in the indoor heat exchanger, so that the room can be dehumidified.

However, when the room temperature is not so high and the humidity is high, dehumidification itself is desired rather than cooling. There is the following example as an air conditioner that independently has a dehumidifying operation function in addition to the cooling operation.

(1) By turning on / off the operation of the weak cooling, a dehumidifying action can be obtained without significantly lowering the indoor temperature. (2) Cooling and dehumidifying indoor air by cooling operation,
The temperature drop due to cooling is offset by the heat generated by the electric heater.

(3) The indoor heat exchanger is divided into two and an expansion valve is interposed between the two heat exchangers, so that one heat exchanger is an evaporator and the other heat exchanger is an outdoor heat exchanger. Similarly, it also functions as a condenser (reheater), warms the air cooled and dehumidified on the evaporator side and blows it out into the room.

[0006]

In the dehumidifying operation of (1), the evaporation temperature of the refrigerant in the indoor heat exchanger becomes high because of the weak cooling, and the difference between the evaporation temperature and the dew point temperature of the intake air becomes small. Cannot obtain sufficient dehumidifying ability.

In the dehumidifying operation of (2), since it is necessary to generate heat from the heater corresponding to the cooling capacity, it is necessary to prepare a large-sized electric heater, and there is a problem that power consumption increases.

In the dehumidifying operation of (3), since the indoor unit has an expansion valve, a sudden expansion noise of the refrigerant leaks into the room and the residents feel uncomfortable. In addition, the unbalanced cycle of the condenser (outdoor heat exchanger + reheater) is large and the evaporator is small, so the refrigerant liquefied in the condenser is sucked into the compressor without being completely evaporated in the evaporator. There is a concern that liquid back will occur and that the compressor will overheat due to the accumulation of refrigerant in the condenser.

The present invention has been made in view of the above circumstances.
The air conditioner according to the first aspect of the present invention does not require an electric heater, does not increase power consumption, does not leak unpleasant noise to the room, does not cause liquid bag or abnormal overheating of the compressor, and The purpose of the present invention is to dehumidify without lowering the temperature and to accelerate the rise of dehumidifying action.

In addition to the object of the first invention, the air conditioner of the second invention ensures a good ventilation path for the auxiliary indoor heat exchanger and the main indoor heat exchanger while avoiding an increase in the size of the indoor unit. It is possible to improve the heat exchange efficiency between the refrigerant and the sucked air, and to obtain the energy saving effect.

An air conditioner according to a third aspect of the invention has an object of increasing the dehumidifying capacity in addition to the object of the second aspect of the invention. The air conditioner of the fourth to seventh inventions aims to further accelerate the rise of the dehumidifying action in addition to the object of any one of the first to third inventions.

[0012]

The air conditioner of the first invention comprises a refrigeration cycle in which a compressor, an outdoor heat exchanger, an expansion valve and an indoor heat exchanger are sequentially connected to circulate a refrigerant, and a compressor The refrigerant discharged forms an outdoor heat exchanger, an expansion valve, a cooling cycle that returns to the compressor through the indoor heat exchanger, and a cooling operation means that performs the cooling operation by setting the expansion valve to a predetermined opening degree,
The refrigerant discharged from the compressor forms a dehumidification cycle that returns to the compressor through the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger, and the evaporation of the refrigerant is completed in a part of the indoor heat exchanger, and the remaining part Then, the dehumidifying operation means that controls the opening of the expansion valve to perform the dehumidifying operation so that it is in the overheat region, and the initial opening of the expansion valve when the dehumidifying operation is started is smaller than the initial opening when the cooling operation is started. And a control means for setting.

The air conditioner of the second invention is the air conditioner of the first invention, wherein the indoor heat exchanger comprises an auxiliary indoor heat exchanger and a main indoor heat exchanger. An indoor unit for accommodating the exchanger together with a cross-flow type indoor fan is provided, suction ports are formed on the front surface and the upper surface of the indoor unit, and the main indoor heat exchanger includes a first heat exchanger and a second heat exchanger. The two heat exchangers are arranged in an inverted V shape so as to surround the indoor fan, the first heat exchanger is opposed to the front suction port, and the second heat exchanger is opposed to the upper suction port. Then, the auxiliary indoor heat exchanger is arranged between the second heat exchanger and the suction port on the upper surface, and the dehumidifying operation means completes the evaporation of the refrigerant in the auxiliary indoor heat exchanger and the refrigerant in the main indoor heat exchanger. The opening degree of the expansion valve is controlled so that it will be in the overheat region.

An air conditioner according to a third aspect of the present invention is the air conditioner according to the second aspect, wherein temperature detecting means for detecting the temperature Tc of the main indoor heat exchanger and the temperature Tj of the auxiliary indoor heat exchanger is provided, and the dehumidifying operation means is The opening degree of the expansion valve is controlled so that only the detected temperature Tj becomes equal to or lower than the dew point temperature of the intake air.

An air conditioner according to a fourth aspect of the present invention is the air conditioner according to any one of the first to third aspects, further comprising temperature detecting means for detecting the temperature Ta of the intake air, and the control means when the dehumidifying operation is started. The initial opening of the expansion valve is set to a value smaller than the initial opening at the start of the cooling operation and corresponding to the detected temperature Ta.

An air conditioner according to a fifth aspect of the present invention is the air conditioner according to any one of the first to third aspects of the present invention, further comprising temperature detecting means for detecting the temperature Ta of the intake air, and humidity detecting means for detecting the humidity Ha of the intake air. The control means sets the initial opening of the expansion valve when the dehumidifying operation is started to be smaller than the initial opening when the cooling operation is started, and detects the temperature Ta and the detected humidity H.
Set to a value according to a.

The air conditioner of a sixth invention is the air conditioner according to any one of the first to third inventions, wherein the control means sets the initial opening of the expansion valve when the dehumidifying operation is started to the initial opening when the cooling operation is started. Set to a value smaller than the opening and according to the operating frequency of the compressor.

An air conditioner according to a seventh aspect of the present invention is the air conditioner according to any one of the first to third aspects, wherein temperature detecting means for detecting the temperature To of the outdoor air is provided, and the control means is provided when dehumidifying operation is started. The initial opening of the expansion valve is set to a value smaller than the initial opening at the start of the cooling operation and corresponding to the detected temperature To.

[0019]

In the air conditioner of the first aspect of the present invention, the refrigerant flowing in the indoor heat exchanger expands so that the vaporization is completed in a part of the inflow side and the rest of the indoor heat exchanger is in the superheat region. Since the valve is controlled, the intake air is cooled and dehumidified in a part of the inflow side of the indoor heat exchanger, but the intake air is not cooled and dehumidified in the remaining superheat region.
Moreover, since the indoor heat exchanger is partially cooled, the amount of cooling is small, and the intake air is blown out indoors without much lowering the temperature. When the dehumidifying operation is started, the opening degree of the expansion valve is set to be smaller than the initial opening degree during the cooling operation, and the evaporation amount and evaporation temperature of the refrigerant in the indoor heat exchanger are suitable for dehumidification. Promptly transition to.

In the air conditioner of the second invention, in the first invention, the indoor heat exchanger is composed of an auxiliary indoor heat exchanger and a main indoor heat exchanger, and the indoor unit has a suction port on the entire surface and an upper surface. The indoor air is sucked from each of the suction ports.
Of these, the room air sucked from the suction port on the upper surface first passes through the auxiliary indoor heat exchanger and then the main indoor heat exchanger.
During the dehumidifying operation, the refrigerant first flows to the auxiliary indoor heat exchanger, where it draws heat from the intake air and evaporates. As a result, the sucked air is cooled and dehumidified. The refrigerant that has passed through the auxiliary indoor heat exchanger flows to the next main indoor heat exchanger, but in the main indoor heat exchanger, it becomes an overheat region and hardly exchanges heat with air. Thus, the intake air is cooled and dehumidified only in the auxiliary indoor heat exchanger, and is not cooled or dehumidified in the main indoor heat exchanger. Moreover, the amount of cooling by the auxiliary indoor heat exchanger is small, and the intake air is blown out into the room without a temperature drop. When this dehumidifying operation is started, an opening smaller than the initial opening when the cooling operation is started is set as the initial opening of the expansion valve, and the temperature of the auxiliary indoor heat exchanger quickly shifts to a temperature suitable for dehumidification. To do.

In the air conditioner of the third invention, in the second invention, the opening degree of the expansion valve is controlled so that only the temperature Tj of the auxiliary indoor heat exchanger becomes equal to or lower than the dew point temperature of the intake air during the dehumidifying operation. It

In the air conditioner of the fourth invention, in any one of the first to third inventions, the initial opening of the expansion valve when the dehumidifying operation is started is smaller than the initial opening when the cooling operation is started. Moreover, it is set to a value according to the detected temperature Ta.

In the air conditioner of the fifth invention, in any one of the first to third inventions, the initial opening of the expansion valve when the dehumidifying operation is started is smaller than the initial opening when the cooling operation is started. In addition, the value is set according to the detected temperature Ta and the detected humidity Ha.

The air conditioner of a sixth invention is the air conditioner according to any one of the first to third inventions, wherein the initial opening of the expansion valve when the dehumidifying operation is started is smaller than the initial opening when the cooling operation is started. Moreover, it is set to a value according to the operating frequency of the compressor.

In the air conditioner of the seventh invention, in any one of the first to third inventions, the initial opening of the expansion valve when the dehumidifying operation is started is smaller than the initial opening when the cooling operation is started. Moreover, it is set to a value according to the detected temperature To.

[0026]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, 1 is an indoor unit,
The room has a suction port 2 for indoor air on the front surface, a suction port 3 for indoor air on the upper surface, and further has a discharge port 4 for air for air conditioning (cooling air, dehumidified air, heating air, etc.) on the lower front surface. ing.

In the indoor unit 1, the suction ports 2 and 3 are provided.
To the outlet 4 to form a ventilation path 5. In the ventilation passage 5, a dustproof (and deodorizing) filter 6 is provided inside the suction ports 2 and 3, and a main indoor heat exchanger 8 and an auxiliary indoor heat exchanger 7 are arranged inside the filter 6. Is established. Then, a horizontal flow type indoor fan 9 is disposed inside the heat exchangers 7 and 8.

The main indoor heat exchanger 8 is divided into two, a first heat exchanger 8a and a second heat exchanger 8b.
b is arranged in an inverted V shape so as to surround the indoor fan 9.
The first heat exchanger 8a faces the suction port 2 on the front face, and the second heat exchanger 8b faces the suction port 3 on the top face. The auxiliary indoor heat exchanger 7 is disposed between the second heat exchanger 8b and the suction port 3, that is, at a position on the windward side above the second heat exchanger 8b in the indoor air suction flow path. .

The radiating fins of the first heat exchanger 8a and the radiating fins of the second heat exchanger 8b are in contact with each other, but the second
A gap is secured between the heat radiation fins of the heat exchanger 8b and the heat radiation fins of the auxiliary indoor heat exchanger 7, and both heat radiation fins are in a non-contact state.

The drain receiving portion 1 is provided below the first heat exchanger 8a.
9 is formed. A drain receiving portion 19 is also formed below the second heat exchanger 8b and the auxiliary indoor heat exchanger 7. When the indoor fan 9 rotates, indoor air is sucked into the indoor unit 1 through the suction port 2 and the suction port 3, respectively. The suction air from the suction port 2 passes through the filter 6,
Furthermore, it flows to the indoor fan 9 side through the first heat exchanger 8a. After passing through the filter 6, the suction air from the suction port 3 first flows through the auxiliary indoor heat exchanger 7, and then flows through the second heat exchanger 8b to the indoor fan 9 side.

A left-right louver 10 is provided in the ventilation passage 5 at a position facing the outlet 4 on the downstream side of the indoor fan 9. The left-right louver 10 is for manually setting the direction of the blowing air in the left-right direction of the indoor unit 1.

A plurality of, for example, a pair of vertical louvers 1 is provided at the position of the air outlet 4 on the downstream side of the horizontal louvers 10.
1, 11 are provided side by side vertically. The vertical louvers 11 and 11 are driven by a single motor in conjunction with each other, and during operation, rotate to the left in the drawing to open the air outlet 4 and change the direction of the blown air in the vertical direction of the indoor unit 1. In addition, when the operation is stopped, it rotates to the right in the drawing to close the air outlet 4 to prevent dust from entering the indoor unit 1.

On the other hand, as shown in FIG. 1, an outdoor heat exchanger 23 is connected to the discharge port of the compressor 21 via a four-way valve 22, and an expansion mechanism such as an electric expansion valve 24 is connected to the outdoor heat exchanger 23. Connected by piping. The degree of opening of the electric expansion valve 24 continuously changes in accordance with the number of input drive pulses.

One end of the auxiliary indoor heat exchanger 7 is connected to the electric expansion valve 24 by piping, and the other end of the auxiliary indoor heat exchanger 7 is connected to the main indoor heat exchanger 8 (the first heat exchanger 8a and the second heat exchanger). The device 8b) is piped. And the main indoor heat exchanger 8
The suction port of the compressor 1 is connected via a pipe to the four-way valve 2.

Thus, a heat pump type refrigeration cycle capable of cooling, dehumidifying and heating is constructed. At the time of cooling, the refrigerant discharged from the compressor 1 flows from the four-way valve 22 to the outdoor heat exchanger 23, the electric expansion valve 24, the auxiliary indoor heat exchanger 7, and the main indoor heat exchanger 8, as indicated by solid arrows in the drawing. , And a cooling cycle in which the refrigerant having passed through the main indoor heat exchanger 8 returns to the compressor 1 through the four-way valve 22 is formed. That is, the outdoor heat exchanger 23 functions as a condenser, and the auxiliary indoor heat exchanger 7 and the main indoor heat exchanger 8 function as an evaporator.

During dehumidification, a dehumidification cycle in which the refrigerant flows in the same direction as during cooling is formed. During heating, the four-way valve 22 is switched so that the refrigerant discharged from the compressor 1 flows from the four-way valve 22 to the main indoor heat exchanger 8, the auxiliary indoor heat exchanger 7, and the electric expansion as shown by the broken line arrow in the figure. A heating cycle is formed in which the refrigerant sequentially flows to the valve 24 and the outdoor heat exchanger 23, and the refrigerant passing through the outdoor heat exchanger 23 returns to the compressor 1 through the four-way valve 22. That is, the auxiliary indoor heat exchanger 7 and the main indoor heat exchanger 8 function as a condenser, and the outdoor heat exchanger 23 functions as an evaporator.

As shown in FIG. 2, the heat exchanger temperature sensor 1 is attached to the heat exchange pipe on the outlet side of the auxiliary indoor heat exchanger 7.
3 is attached, and the heat exchanger temperature sensor 14 is attached to the heat exchange pipe in the middle of the first heat exchanger 8a.

An indoor temperature sensor 15 and an indoor humidity sensor 16 are provided in the indoor air intake passage from the intake port 2 to the main indoor heat exchanger 8. The heat exchanger temperature sensor 17 is attached to the outdoor heat exchanger 23. Further, an outdoor fan 25 is provided near the outdoor heat exchanger 23, and the outdoor air sucked by the operation of the outdoor fan 25 is supplied to the outdoor heat exchanger 23. In this outdoor air intake flow path,
An outdoor temperature sensor 18 is provided.

The commercial AC power supply 30 is connected to the inverter circuit 3
1. The speed control circuits 32 and 33 and the control unit 40 are connected. Then, the control unit 40 includes an inverter circuit 31,
Speed control circuits 32 and 33, vertical louver motor 11
M, heat exchanger temperature sensors 13 and 14, indoor temperature sensor 1
5, the indoor humidity sensor 16, the heat exchanger temperature sensor 17, the outdoor temperature sensor 18, the four-way valve 22, the electric expansion valve 24, and the light receiving unit 41 are connected.

The inverter circuit 31 rectifies the power supply voltage, converts it into an alternating current of a frequency F (and voltage) according to a command from the control section 40, and outputs it. This output is the drive power of the drive motor (compressor motor) of the compressor 21.

The speed control circuit 32 is used for the outdoor fan motor 2
By controlling the supply of the power supply voltage to 5M (for example, energization phase control), the speed of the outdoor fan motor 25M (the amount of air blown by the outdoor fan 25) is set to the speed according to the command from the control unit 40. The speed control circuit 33 sets the speed of the indoor fan motor 9M (the amount of air blown by the indoor fan 9) to a speed according to a command from the control unit 40 by controlling the supply of the power supply voltage to the indoor fan motor 9M (for example, energizing phase control). I do.

The light receiving section 42 receives infrared light emitted from a remote control type operation device (hereinafter abbreviated as a remote controller). The control unit 40 performs overall control of the air conditioner, and includes the following [1] to [3] as main functional means.

[1] When the cooling operation mode is set by the remote controller 42, the cooling cycle is formed to form the outdoor heat exchanger 23.
The condenser, the auxiliary indoor heat exchanger 7 and the main indoor heat exchanger 8
Both as an evaporator, and a cooling operation means for executing the cooling operation by setting the electric expansion valve 24 to a predetermined opening degree.

[2] When the dehumidifying operation mode is set by the remote controller 42, a dehumidifying cycle is formed, and at the same time, the refrigerant is evaporated in the auxiliary indoor heat exchanger 7 which is a part of the indoor heat exchanger to perform heat exchange in the main room. In the container 8, a dehumidifying operation unit that controls the opening degree of the electric expansion valve 24 so that the refrigerant is in the overheat region and executes the dehumidifying operation.

[3] Control means for setting the initial opening of the electric expansion valve 24 when the dehumidifying operation is started to be smaller than the initial opening when the cooling operation is started. Next, the operation of the above configuration will be described with reference to the flowchart of FIG.

When the dehumidifying operation mode is set by the remote controller 42 and the operation starting operation is performed, the compressor 21 is activated to form the dehumidifying cycle, and the operation of the indoor fan 9 and the outdoor fan 25 is started. Dehumidification operation starts.

At this time, the opening degree of the electric expansion valve 24 is set to the initial opening degree "150" during the dehumidifying operation. During the dehumidifying operation, the temperature Ta of the air sucked into the indoor unit 1 is detected by the indoor temperature sensor 15, and the detected temperature Ta and the set temperature Ts are detected.
The difference ΔT (= Ta−Ts) from Then, the operating frequency F of the compressor 21 is controlled according to the temperature difference ΔT. That is, as the temperature difference ΔT increases, the operating frequency F
Is set high to increase the capacity of the compressor 21.

Since the actual value of the operating frequency F during the dehumidifying operation is much lower than that during the cooling operation, the power consumption can be reduced and the energy saving effect can be obtained.

Simultaneously with this operation frequency control, the opening degree of the electric expansion valve 24 is controlled so that the evaporation of the refrigerant in the auxiliary indoor heat exchanger 8 is completed and the refrigerant in the main indoor heat exchanger 7 is in the overheat region. .

Specifically, the temperature Tj of the auxiliary indoor heat exchanger 7 detected by the heat exchanger temperature sensor 13 is kept below the dew point temperature of the intake air, and the heat exchanger temperature sensor 14 is used.
The difference ΔTcj (= Tc-Tj) between the temperature Tc of the main indoor heat exchanger 8 detected at 1 and the detected temperature Tj is a predetermined value ΔTcj ₁
The opening degree of the electric expansion valve 24 is controlled so that The predetermined value ΔTcj ₁ is a value proportional to the operating frequency F of the compressor 21.

For example, the temperature difference ΔTcj is a predetermined value ΔTcj ₁
If it is larger, the opening degree of the electric expansion valve 24 is reduced by a predetermined value for each control loop. The temperature difference ΔTcj is a predetermined value ΔT
If it is smaller than cj _1, the opening degree of the electric expansion valve 24 is increased by a predetermined value for each control loop. When the temperature difference ΔTcj matches the predetermined value ΔTcj ₁ , the opening degree of the electric expansion valve 24 at that time is maintained as it is.

By this opening degree control, the sucked air is cooled and dehumidified only in the auxiliary indoor heat exchanger 7, and is blown out into the room without heat exchange in the main indoor heat exchanger 8. Moisture adhering to the auxiliary indoor heat exchanger 7 drops along the heat exchange pipe and the radiation fins of the heat exchanger 7 to the drain receiving portion 19.

Here, the dehumidifying action of the auxiliary indoor heat exchanger 7 will be described in detail. When the operating frequency F rises, the circulation amount of the refrigerant increases. If the target value ΔTcj _{1 of the} temperature difference ΔTcj is constant for any operating frequency F, the refrigerant circulation amount increases,
The evaporation of the refrigerant does not end only in the auxiliary indoor heat exchanger 7, and the evaporation of the refrigerant also occurs in the main indoor heat exchanger 8. In this case, not only the function of dehumidification but also the function of cooling (that is, lowering the temperature of indoor air) is exhibited.

The temperature difference ΔTcj according to the change of the operating frequency F
Can be changed, the evaporation of the refrigerant can be terminated only by the auxiliary indoor heat exchanger 7 even if the refrigerant circulation amount increases. Therefore, the predetermined value ΔTcj _{1 is changed} to the operation frequency F
It is set to a value proportional to. This allows
Irrespective of the change in the compression function force, the dehumidifying action is given only to the auxiliary indoor heat exchanger 7, so that the decrease in the indoor temperature can be surely suppressed.

If the temperature difference ΔTcj is smaller than the predetermined value ΔTcj ₁ , the temperature of the auxiliary indoor heat exchanger 7 (that is, the evaporation temperature)
Since it is determined that Tj is in a high state, the opening degree of the electric expansion valve 24 is controlled to be narrowed.

When the opening degree of the electric expansion valve 24 is narrowed, the evaporation pressure is lowered and the evaporation temperature Tj is lowered, and the difference between the evaporation temperature Tj and the intake air temperature Ta becomes large. This allows
The heat exchange between the refrigerant and the air in the auxiliary indoor heat exchanger 7 is promoted, and the evaporation of the refrigerant ends only in the auxiliary indoor heat exchanger 7. At this time, the superheated area of the refrigerant becomes large, and all of the main indoor heat exchangers 8 become superheated areas.
Temperature Tc approaches the intake air temperature Ta. That is,
No cooling action occurs in the main room heat exchanger 8.

Further, according to this control, the evaporation temperature Tj is greatly reduced as compared with the case where the refrigerant is evaporated in the entire indoor heat exchanger (auxiliary indoor heat exchanger 7 + main indoor heat exchanger 8) as in the case of cooling. be able to.

That is, supposing that the refrigerant evaporates in the entire indoor heat exchanger, when the evaporation temperature is greatly lowered to the dew point temperature of the intake air or lower in order to obtain the dehumidifying capacity, the temperature of the air blown into the room is increased. Will fall.

On the other hand, in the case of dehumidification by only the auxiliary indoor heat exchanger 7, the temperature Tc of the main indoor heat exchanger 8 excluding the auxiliary indoor heat exchanger 7 is lowered even if the evaporation temperature is lowered to the intake air temperature A or lower. Is the air temperature, and because the indoor fan 9 is operating at a low speed, it is difficult for the indoor air temperature to drop. That is, the dehumidifying ability can be increased without lowering the indoor air temperature.

If the heat exchanger area is small like the auxiliary indoor heat exchanger 7, even if the evaporation temperature is greatly lowered,
It is considered that sufficient dehumidifying capacity may not be obtained. For example, the auxiliary indoor heat exchanger 7 and the main indoor heat exchanger 8
If the ratio of the area of the heat exchanger with that of 1: 5 is 1: 5, the ratio of the area of the auxiliary indoor heat exchanger 7 to the total area of the indoor heat exchanger is 1/6. If there is a difference between the dew point temperature and the evaporation temperature in the value corresponding to the reciprocal number, almost the same amount of moisture will be condensed as in the case of dehumidifying the entire indoor heat exchanger. That is, the dehumidifying ability substantially equal to the case where the entire indoor heat exchanger is dehumidified is obtained.

In particular, a conventional electric heater for reheating is not required, so that power consumption does not increase. Unlike the conventional case, since the expansion valve (to divide the indoor heat exchanger into the evaporator and the reheater) is not provided in the indoor unit, there is no problem that the rapid expansion noise of the refrigerant leaks into the room. In addition, in the type in which the expansion valve is installed in the indoor unit, the unbalanced cycle in which the condenser (outdoor heat exchanger + reheater) is large and the evaporator is small, and the refrigerant liquefied in the condenser is used in the evaporator. There was a concern that a liquid bag may be sucked into the compressor without being completely evaporated, or that the refrigerant may be accumulated in the condenser and the compressor may be overheated.

Further, in this embodiment, a gap is secured between the heat radiation fins of the auxiliary indoor heat exchanger 7 and the heat radiation fins of the main indoor heat exchanger 8 so that both heat radiation fins are not in contact with each other, that is, they are thermally separated. Since it is in the other state, heat transfer between the auxiliary indoor heat exchanger 7 and the main indoor heat exchanger 8 is prevented as much as possible, and a sufficient temperature difference can be secured between the dehumidifying area and the overheating area. Therefore, the evaporation temperature of the refrigerant can be sufficiently lowered, and a high dehumidifying capacity can be secured.

With respect to the structure of the indoor unit 1, there is a suction port 2 on the front surface and a suction port 3 on the upper surface. The suction ports 2 and 3 are connected to the first heat exchanger 8a of the main indoor heat exchanger 8 and the first heat exchanger 8a. Two
The two heat exchangers 8a and 8b are arranged in an inverted V-shape so as to surround the indoor fan 9 with the heat exchangers 8b facing each other, and between the second heat exchanger 8b and the suction port 3 on the upper surface. Since the auxiliary indoor heat exchanger 7 is disposed in the main unit, a good ventilation path for the auxiliary indoor heat exchanger 7 and the main indoor heat exchanger 8 can be secured while avoiding an increase in the size of the indoor unit 1. Thereby, the heat exchange efficiency between the refrigerant and the intake air is improved, and an energy saving effect is obtained.

By the way, when the dehumidifying operation is started, the opening degree of the electric expansion valve 24 is first set to the initial opening degree. This initial opening is a value smaller than the initial opening when the cooling operation is started.

For example, if the initial opening "200" is set at the start of the cooling operation, the initial opening "150" is set at the start of the dehumidifying operation. Numbers "200" and "1
50 ″ is the number of drive pulses supplied to the electric expansion valve 24. The larger the value, the larger the opening degree of the electric expansion valve 24.

By setting the initial opening "150", as shown in FIG.
As shown in (Experimental data), the temperature Tj of the auxiliary indoor heat exchanger 7 can be quickly shifted to a temperature equal to or lower than the dew point temperature, which is a value suitable for dehumidification. This accelerates the rise of the dehumidifying action.

At the initial opening "50", the temperature drop is so great that the auxiliary indoor heat exchanger 7 freezes. on the other hand,
The initial opening may not be a fixed value but may be changed according to the situation. There are four examples below.

(1) The initial opening is smaller than the initial opening when the cooling operation is started, and the temperature T detected by the indoor temperature sensor 15 is
Set as shown in Table 1 according to a. This takes into consideration that the dew point temperature of the intake air differs depending on the temperature Ta of the intake air.

[0069]

[Table 1]

(2) The initial opening is smaller than the initial opening when the cooling operation is started, and the temperature T detected by the indoor temperature sensor 15 is
a and humidity detected by the indoor humidity sensor 16 (absolute humidity) H
Set according to Table 2 as shown in Table 2.

[0071]

[Table 2]

(3) The initial opening is set smaller than the initial opening at the start of the cooling operation, and is set as shown in Table 3 according to the operating frequency F of the compressor 21. This takes into consideration that the operating frequency F changes according to the temperature Ta of the intake air, and that the dew point temperature differs depending on the temperature Ta of the intake air.

[0073]

[Table 3]

(4) The initial opening is set smaller than the initial opening at the start of the cooling operation and is set as shown in Table 4 according to the temperature To of the outdoor air detected by the outdoor temperature sensor 18. This takes into consideration that the temperature To of the outdoor air affects the temperature Ta of the intake air, and that the dew point temperature of the intake air differs depending on the temperature Ta of the intake air.

[0075]

[Table 4]

It is necessary for the temperature Tj of the auxiliary indoor heat exchanger 7 to become equal to or lower than the dew point temperature by changing the initial opening according to the situation as in (1), (2), (3) and (4). The time is further shortened and the dehumidification action starts up faster.

In this case, among the initial opening degree setting methods (2), (3) and (4), any two methods may be combined, or three methods may be combined. Furthermore, during dehumidifying operation,
As shown by broken lines in FIG. 2, the vertical louvers 11 and 11,
It may be set slightly upward from the horizontal so as to form a short circuit in which blown air is sucked in through the suction port.

As described above, if the short circuit is formed during the dehumidifying operation, the dehumidification can be performed without allowing the wind from the outlet to reach the living area, and the comfortable dehumidification without the feeling of cold wind becomes possible. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

[0079]

As described above, in the air conditioner of the first invention, the expansion valve is arranged so that the evaporation of the refrigerant is completed in a part of the indoor heat exchanger and the refrigerant is in the overheated area in the remaining part. The opening degree of the electric heater is controlled so that the dehumidification operation is executed by this, and the initial opening degree of the expansion valve when the dehumidification operation is started is set smaller than the initial opening degree when the cooling operation is started. It is possible to perform dehumidification without lowering the room temperature, without increasing the power consumption, without causing unpleasant noise in the room, without causing liquid bag or abnormal overheating of the compressor. The dehumidifying action can be started earlier.

In the air conditioner of the second invention, in the first invention, the indoor heat exchanger comprises an auxiliary indoor heat exchanger and a main indoor heat exchanger, and these auxiliary indoor heat exchanger and the main indoor An indoor unit for accommodating the heat exchanger together with the cross-flow type indoor fan is provided, suction ports are formed on the front surface and the upper surface of the indoor unit, and the main indoor heat exchanger is the first heat exchanger and the second heat exchanger. And the two heat exchangers are arranged in an inverted V shape so as to surround the indoor fan, the first heat exchanger is opposed to the front inlet, and the second heat exchanger is attached to the upper inlet. Since the auxiliary indoor heat exchanger is arranged between the second heat exchanger and the suction port on the upper surface so as to face each other, as a further effect, the auxiliary indoor heat exchanger and the main indoor heat exchange are avoided while avoiding an increase in the size of the indoor unit. It is possible to secure a good ventilation path for the Ri improved heat exchange efficiency of the suction air refrigerant, energy saving effect is obtained thus.

In the air conditioner of the third invention, in the second invention, the opening of the expansion valve is controlled so that only the temperature Tj of the auxiliary indoor heat exchanger becomes equal to or lower than the dew point temperature of the intake air during the dehumidifying operation. Therefore, as a further effect, the dehumidifying capacity can be increased.

In the air conditioner of the fourth to seventh inventions, in any one of the first to third inventions, the initial opening of the expansion valve when the dehumidifying operation is started is set to the initial opening when the cooling operation is started. Since it is set to a value smaller than the value and changing according to the situation, as a further effect, the rise of the dehumidifying action can be further accelerated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a refrigeration cycle and a configuration of a control circuit according to an embodiment.

FIG. 2 is a cross-sectional view showing the internal configuration of the indoor unit of the embodiment.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is a diagram showing the relationship between the opening degree of the electric expansion valve and the temperature of the auxiliary indoor heat exchanger according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Indoor unit, 2 ... Suction port, 3 ... Suction port, 4 ... Outlet, 5 ... Ventilation path, 7 ... Auxiliary indoor heat exchanger, 8 ... Main indoor heat exchanger, 8a ... 1st heat exchanger, 8b ... Second heat exchanger, 9
... Indoor fan, 11, 11 ... Vertical louver, 13, 1
4 ... Heat exchanger temperature sensor, 15 ... Indoor temperature sensor, 16
... indoor humidity sensor, 18 ... outdoor temperature sensor, 21 ... compressor, 22 ... four-way valve, 23 ... outdoor heat exchanger, 24 ... motorized expansion valve, 31 ... inverter circuit, 40 ... control section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Hoshi, 336 Tatehara, Fuji City, Shizuoka Prefecture, inside the Fuji Factory, Toshiba Corporation (72) Hiroyuki Tokita, 336, Tatehara, Fuji City, Shizuoka Prefecture, inside the Fuji Factory, Toshiba (72) Inventor Tetsuji Yamashita 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Incorporated company Toshiba Yokohama Works (72) Inventor Shigeo Hirahara 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture In-house Toshiba Yokohama (72) Inventor Person Yasuhiro Kageyama 336 Tatehara, Fuji City, Shizuoka Prefecture, Toshiba Corporation Fuji Factory (72) Inventor Makoto Watanabe 336 Tatehara, Fuji City, Shizuoka Prefecture Toshiba FCC Corporation

Claims (7)

[Claims] 1. A refrigeration cycle in which a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are sequentially connected to circulate a refrigerant, and the refrigerant discharged from the compressor is an outdoor heat exchanger, an expansion valve, and an indoor heat. A cooling operation unit that forms a cooling cycle that returns to the compressor through the exchanger, and that performs the cooling operation by setting the expansion valve to a predetermined opening degree, and the refrigerant discharged from the compressor is an outdoor heat exchanger and an expansion valve. , Forms a dehumidification cycle that returns to the compressor through the indoor heat exchanger, and controls the opening of the expansion valve so that the evaporation of the refrigerant is completed in a part of the indoor heat exchanger and the remaining part is in the overheat region And a dehumidifying operation means for executing the dehumidifying operation, and a control means for setting the initial opening of the expansion valve when the dehumidifying operation is started to be smaller than the initial opening when the cooling operation is started. And an air conditioner. 2. The air conditioner according to claim 1, wherein the indoor heat exchanger comprises an auxiliary indoor heat exchanger and a main indoor heat exchanger, and the auxiliary indoor heat exchanger and the main indoor heat exchanger are connected to each other. An indoor unit for accommodating together with a cross-flow type indoor fan is provided, suction ports are formed on the front and upper surfaces of the indoor unit, and the main indoor heat exchanger is divided into a first heat exchanger and a second heat exchanger. Both heat exchangers are arranged in an inverted V shape so as to surround the indoor fan, the first heat exchanger faces the suction port on the front surface, and the second heat exchanger on the suction port on the upper surface. The auxiliary indoor heat exchanger is arranged between the second heat exchanger and the suction port on the upper surface, and the dehumidifying operation means is configured such that the evaporation of the refrigerant is completed in the auxiliary indoor heat exchanger. In the heat exchanger, control the opening of the expansion valve so that the refrigerant is in the overheated area. An air conditioner characterized by. 3. The air conditioner according to claim 2, further comprising temperature detecting means for detecting a temperature Tc of the main indoor heat exchanger and a temperature Tj of the auxiliary indoor heat exchanger, and the dehumidifying operation means: An air conditioner, wherein the opening degree of the expansion valve is controlled so that only the detected temperature Tj is equal to or lower than the dew point temperature of the intake air. 4. The air conditioner according to any one of claims 1 to 3, further comprising temperature detection means for detecting a temperature Ta of the intake air, wherein the control means controls when the dehumidifying operation is started. An air conditioner, wherein the initial opening of the expansion valve is set to a value smaller than the initial opening at the start of the cooling operation and set to a value according to the detected temperature Ta. 5. The air conditioner according to claim 1, further comprising: temperature detecting means for detecting a temperature Ta of intake air, and humidity detecting means for detecting a humidity Ha of the intake air. The control means sets the initial opening of the expansion valve when the dehumidifying operation is started to be smaller than the initial opening when the cooling operation is started and to a value corresponding to the detected temperature Ta and the detected humidity Ha. A characteristic air conditioner. 6. The air conditioner according to any one of claims 1 to 3, wherein the control means sets the initial opening of the expansion valve when the dehumidifying operation is started to the initial opening when the cooling operation is started. The air conditioner is set to a value that is smaller than the frequency and that corresponds to the operating frequency of the compressor. 7. The air conditioner according to any one of claims 1 to 3, further comprising temperature detecting means for detecting a temperature To of the outdoor air, wherein the control means is provided when dehumidifying operation is started. An air conditioner characterized in that the initial opening of the expansion valve is set to a value smaller than the initial opening at the start of the cooling operation and to a value corresponding to the detected temperature To.