JP2001082755A - Indoor unit for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indoor unit for an air conditioner capable of improving a heat exchanging performance by effectively utilizing a site having a fastest wind velocity. SOLUTION: The indoor unit for an air conditioner comprises a unit body 1 having suction ports 12a, 12 and an air outlet 9 under the ports 12a, 12 at a front panel 2, a main heat exchanger 50A disposed oppositely to the ports and a blower 1 disposed at a rear side of the exchanger 50a in the body, a drain pan 6a disposed under the exchanger 50A, and an auxiliary heat exchanger 50B disposed at a lower front surface side of the exchanger 50A directly above the exchanger 50A to cool a refrigerant to a supercooled state in a dehumidifying operation mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indoor unit of an air conditioner provided with an indoor heat exchanger including a main heat exchanger and an auxiliary heat exchanger.

[0002]

2. Description of the Related Art In an indoor unit of an air conditioner, a heat exchanger and a blower are disposed in the unit body so as to face each other, and the indoor air sucked into the unit body by the operation of the blower is guided to the heat exchanger to generate heat. After being exchanged, it is blown out to the room.

[0003] The above-mentioned heat exchanger has a flat plate shape and is arranged in an upright posture. However, the heat exchanger is arranged to be inclined in order to reduce the height inside the unit body. It was shaped like a letter. In recent years, in order to further increase the heat capacity, a heat exchanger formed in a substantially inverted V-shape in a side view has been frequently used.

This substantially inverted V-shaped heat exchanger comprises a front heat exchanger section and a rear heat exchanger section. Particularly, the upper side of the rear heat exchanger section is the upper and lower surfaces of the unit body. Therefore, a small heat capacity auxiliary heat exchanger is provided here and connected to the rear heat exchanger.

[0005] In addition to the mere heat exchange action,
An indoor unit having an air purifying function is also provided. This air purifier is arranged close to the front surface of the front heat exchanger section, and cleans a part of the room air sucked into the unit main body and then guides it to the front heat exchanger section.

[0006]

By the way, the front heat exchanger portion of the substantially inverted V-shaped heat exchanger is formed in a curved shape, and the air purifier is disposed on the upper front side, and on the lower front side. Is a general structure in which a filter is arranged.

After the room air is sucked into the unit body, it immediately collides with the front heat exchanger, particularly the lower front surface, and exchanges heat. That is, the lower front surface of the front heat exchanger section is the site where the wind speed is the highest, and the heat exchange between the heat exchange air and the refrigerant is performed more effectively than the other sites.

However, no means other than a filter is provided below the front heat exchanger section, and there is a problem that the heat exchange section is not effectively used although it is an efficient heat exchange section.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an air conditioner capable of improving heat exchange performance by effectively utilizing a portion of a heat exchanger having the highest wind speed. It is intended to provide an indoor unit of the machine.

[0010]

In order to satisfy the above object, an indoor unit of an air conditioner according to the present invention is characterized in that a unit body having a suction port provided on a front panel and a blow port provided below the front panel. A main heat exchanger arranged in the unit body facing the suction port and a blower arranged behind the main heat exchanger; a drain pan arranged below the main heat exchanger; An auxiliary heat exchanger that is disposed on the lower front side of the heat exchanger and makes the refrigerant be in a supercooled state in the dehumidifying operation mode.

According to a second aspect, in the indoor unit of the air conditioner according to the first aspect, a refrigeration cycle circuit is configured such that the refrigerant is guided to the auxiliary heat exchanger before the main heat exchanger in the cooling operation mode. It is characterized by that.

According to a third aspect of the present invention, in the indoor unit of the air conditioner according to the second aspect, a refrigerant expansion device is provided upstream of the auxiliary heat exchanger in the cooling operation mode and the dehumidification operation mode. It is characterized in that it is narrowed down more in the dehumidifying operation mode than in the dehumidifying operation mode.

According to a fourth aspect of the present invention, in the indoor unit of the air conditioner according to the first aspect, a refrigerant expansion device is interposed between the main heat exchanger and the auxiliary heat exchanger, and the expansion device is in the heating dehumidifying operation mode. The main heat exchanger is condensed and the auxiliary heat exchanger is constricted so as to perform cooling.

According to a fifth aspect, in the indoor unit of the air conditioner according to the first aspect, an air purifier is disposed in front of the main heat exchanger and above the auxiliary heat exchanger, and the main heat exchange of the unit body is performed. A support means for detachably supporting the air purifier without interfering with the auxiliary heat exchanger is provided on the front side of the vessel.

According to a sixth aspect of the present invention, there is provided an indoor unit of an air conditioner having a suction port provided on a front panel and a discharge port provided below the suction port. A main heat exchanger formed in the unit main body and formed in a substantially inverted V-shape in a side view and opposed to the suction port, and a blower arranged near the main heat exchanger; A front drain pan and a rear drain pan arranged below the lower part and the rear part, and a pair of a pair arranged to be disposed on the upper surface side at the lower front side and the rear part at the front of the main heat exchanger and to supercool the refrigerant in the dehumidifying operation mode. And an auxiliary heat exchanger.

According to a seventh aspect, in the indoor unit of the air conditioner according to the sixth aspect, the refrigeration cycle circuit is configured such that the refrigerant is guided to the auxiliary heat exchanger before the main heat exchanger in the cooling operation mode. It is characterized by that.

According to an eighth aspect of the present invention, in the indoor unit of the air conditioner according to the seventh aspect, a throttle device is provided upstream of the auxiliary heat exchanger in the cooling operation mode. It is characterized in that the aperture is greatly reduced in the mode.

By adopting the means for solving the above problems, an auxiliary heat exchanger is arranged on the lower front side of the main heat exchanger at the highest wind speed, and the auxiliary heat exchanger is dehumidified heat exchange in the dehumidifying operation mode. The dehumidification performance is improved by increasing the amount of dehumidification. In addition, the drain generated in the auxiliary heat exchanger immediately flows to the drain pan without flowing to the main heat exchanger, thereby preventing re-evaporation in the main heat exchanger.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an indoor unit of the air conditioner is configured. The unit body 1
It comprises a front panel 2, an upper panel 3, and a rear plate 4 integrally provided with both sides, a back and a bottom, and is formed in a horizontally long box shape.

Inside the unit body 1, an indoor heat exchanger 5 formed in a substantially inverted V-shape when viewed from the side is disposed. In the indoor heat exchanger 5, a large number of fins f are juxtaposed with a small gap therebetween, and a heat exchange pipe p forming a refrigerant flow passage penetrates these fins f.

The indoor heat exchanger 5 will be further described. The indoor heat exchanger 5 comprises a main heat exchanger 50A and an auxiliary heat exchanger 50B. The main heat exchanger 50A includes a front heat exchanger section 5a located on the front side and a rear heat exchanger section 5b located on the back side. The auxiliary heat exchanger 50B includes a front auxiliary heat exchanger section 5c arranged close to the lower front side of the front heat exchanger section 5a, and a rear side arranged along the upper surface of the rear heat exchanger section 5b. And an auxiliary heat exchanger section 5d.

A front drain pan 6a is disposed immediately below the front heat exchanger section 5a and the front auxiliary heat exchanger section 5c, and a rear drain pan 6b is disposed immediately below the rear heat exchanger section 5b.
The front and rear drain pans 6a and 6b are provided integrally with the rear plate 4.

An indoor blower 7 having a cross flow fan is arranged between the front heat exchanger 5a and the rear heat exchanger 5b, which are inside the indoor heat exchanger 5. Rear plate 4
Is bent from the rear side of the indoor blower 7, which is the lower part of the rear drain pan 6b, to the bottom part, and an air passage 8 is formed between the lower part of the front drain pan 6a and an extended part thereof.

An outlet 9 is provided at the lower part of the front panel 2 which forms the tip of the air passage 8 and along the width direction.
The outlet 9 is provided with a wind direction guide (not shown) that combines a plurality of vertical and horizontal louvers to automatically change the direction of the wind blown from the outlet 9.

On the other hand, a frame-shaped crosspiece is fitted into the upper panel 3, and this space is formed by the upper suction port 1
It is formed as 1. The front panel 2 has an R-shaped cross section, and is provided with front suction ports 12a and 12b having different structures in two stages of an upper portion and a lower portion.

An air purifier 13 is disposed at a position facing the front suction port 12a of the front panel 2 and close to the upper front side of the front heat exchanger section 5a. The air purifier 13 includes an electric precipitator for removing dust and water vapor in a room, and a high-performance deodorizing filter having a honeycomb activated carbon structure for removing a smell in a room. They are arranged side by side via a certain support mechanism 40.

When the operation start button of the remote controller (not shown) is pressed, the refrigeration cycle operation for the indoor heat exchanger 5 and the driving of the indoor blower 7 are started. You.

The room air is supplied to the inlets 12a, 12b, 11 of the front panel 2 and the upper panel 3 of the unit body 1.
From the unit body 1. In particular, the indoor air sucked from the front suction port 12a first passes through the air purifier 13 so that impurities such as dust and water vapor contained in the indoor air are captured and removed. Guided heat exchange.

The indoor air sucked from the front suction port 12b and the upper suction port 11 is directly guided to the indoor heat exchanger 5 to exchange heat, and the air which has flowed through the air cleaner 13 and a part of the indoor heat exchanger 5 is provided. After being joined, the air is guided to the air passage 8 through the indoor blower 7 and is blown out from the outlet 9 into the indoor space.

An indoor unit of an air conditioner basically constructed and operating as described above, and the present invention comprises a main heat exchanger 50A and an auxiliary heat exchanger 50B as described below. The indoor heat exchanger 5 is characterized.

FIG. 2 shows a refrigeration cycle circuit of the air conditioner. As described above, the indoor heat exchanger 5 including the main heat exchanger 50A and the auxiliary heat exchanger 50B is disposed in the indoor unit, and is connected to each other in series.

The indoor heat exchanger 5 includes a compressor 20 housed in an outdoor unit (not shown), a four-way valve 21, an outdoor heat exchanger 22, and an electronic expansion valve 23 serving as a refrigerant expansion device. It is connected to form a heat pump type refrigeration cycle through the heat pump.

The compressor 20, the four-way valve 21 and the electronic expansion valve 23 are connected to a control device 25. The control device 25 controls the operation frequency of the compressor 20, and the four-way valve 21 has four ports. And the electronic expansion valve 23 controls the throttle amount.

The white arrows in FIG. 2 indicate the flow of the refrigerant in the dehumidifying operation mode. That is, the high-temperature and high-pressure refrigerant gas discharged from the compressor 20 is guided to the outdoor heat exchanger 22 via the four-way valve 21 and condensed and liquefied. The hatching symbol in the outdoor heat exchanger 22 in the figure indicates a state in which the refrigerant gas is liquefied.

The liquefied refrigerant that has exited the outdoor heat exchanger 22 is reduced in pressure by the electronic expansion valve 23 while its flow rate is greatly reduced. Here, the control device is configured so that the amount of throttle is greater than in the cooling operation mode described later. 25 controls the electronic expansion valve 23.

The liquefied refrigerant is guided from the electronic expansion valve 23 to the auxiliary heat exchanger 50B constituting the indoor heat exchanger 5. Since the flow rate of the refrigerant is greatly reduced, the refrigerant evaporates completely in the course of flowing through the auxiliary heat exchanger 50B. The refrigerant enters a supercooled state to perform a cooling function, and the temperature of the auxiliary heat exchanger 50B becomes extremely low.

When the refrigerant completely evaporated in the auxiliary heat exchanger 50B is led to the main heat exchanger 50A, it flows in a so-called superheat state here. Then, it is sucked into the compressor 20 via the four-way valve 21 and circulates again in the above-described path.

As schematically shown in FIG. 3, the auxiliary heat exchanger 50B may be arranged in a concentrated manner on the lower front side of the main heat exchanger 50A where the wind speed is greatest. Therefore, while the refrigerant that exchanges heat in the auxiliary heat exchanger 50B is in a supercooled state, the room air is completely cooled and dehumidified by the auxiliary heat exchanger 50B.

Since the refrigerant is in the superheat state in the main heat exchanger 50A, the room air once cooled and dehumidified is heated. After leaving the main heat exchanger 50A, the room air rises to about room temperature, and the outlet 9
From the room. Therefore, an efficient dehumidifying action is performed on the indoor space.

That is, the auxiliary heat exchanger 50 is used to suppress a decrease in room temperature due to sensible heat and improve dehumidifying efficiency due to latent heat.
B as a dehumidifying heat exchanger, and the dehumidifying heat exchanger 50B
The controller 25 performs electronic expansion so that the difference between the inlet temperature of the indoor heat exchanger 5 and the intermediate temperature is set as a superheat amount so that this value is set so that the refrigerant evaporates completely. The valve 23 is controlled.

By setting the position of the auxiliary heat exchanger 50B with respect to the main heat exchanger 50A, the temperature of the auxiliary heat exchanger 50B becomes lower than the temperature of the indoor heat exchanger in the conventional dehumidifying operation mode. Latent heat increases. Evaporation of the refrigerant is surely completed in the auxiliary heat exchanger 50B, and there is no temperature drop when guided to the main heat exchanger 50A. Therefore,
The temperature of the air blown out from the outlet 9 rises near room temperature, the sensible heat decreases, and an efficient dehumidifying operation is performed.

Further, the heat capacity of the indoor heat exchanger 5 can be increased without changing the size of the unit body 1, thereby improving the heat exchange efficiency and the heat exchange performance.
The wind speed distribution of the indoor air flowing through the air becomes uniform and smooth, and the quiet operation is performed while suppressing the generation of the blowing noise.

Since the front auxiliary heat exchanger section 5c constituting the auxiliary heat exchanger 50B is disposed immediately above the front drain pan 6a, the drain water generated here is used for the main heat exchanger 50B.
It flows down to the front drain pan 6a without flowing to the front heat exchanger section 5a constituting A. Therefore, re-evaporation of the drain water in the front heat exchanger section 5a is prevented.

A refrigeration cycle circuit as shown in FIG. 4 may be configured. Auxiliary heat exchanger 5 constituting indoor heat exchanger 5
An auxiliary electronic expansion valve 30 as an auxiliary refrigerant throttle device is provided between the main heat exchanger 50A and the main heat exchanger 50A. Note that, as described above, the electronic expansion valve 23 as the refrigerant expansion device is still provided between the outdoor heat exchanger 22 and the auxiliary heat exchanger 50B.

When the dehumidifying operation mode is designated, a controller (not shown) switches the four-way valve 21 in the heating operation mode. The refrigerant gas discharged from the compressor 20 circulates in the direction indicated by the arrow in the figure.

At the same time, the control device restricts only the auxiliary electronic expansion valve 30 by a predetermined amount, and makes the electronic expansion valve 23 almost open. The refrigerant gas is supplied to the main heat exchanger 50 via the four-way valve 21.
The liquid is condensed and liquefied by A, is throttled by the auxiliary electronic expansion valve 30, is guided by the auxiliary heat exchanger 50 </ b> B, evaporates, and is sucked into the compressor 20 via the electronic expansion valve 23 and the outdoor heat exchanger 22.

On the other hand, the indoor air sucked into the unit main body 1 exchanges heat with the auxiliary heat exchanger 50B located on the upstream side to deprive the latent heat of evaporation of the refrigerant.
It exchanges heat with A to absorb the condensation heat of the refrigerant.

That is, since the auxiliary heat exchanger 50B performs the cooling and dehumidifying action on the indoor air and the main heat exchanger performs the reheating action, the efficient heating dehumidifying operation can be performed.

As shown in FIGS. 5 (A) and 5 (B), a unit main body 1 having an auxiliary heat exchanger 50B on the lower front side of the main heat exchanger 50A and an air cleaner 13 mounted above the auxiliary heat exchanger 50B.
And an air purifier 13 is provided on the front side of the main heat exchanger 50A.
The support mechanism (supporting means) 40 for detachably supporting the above is provided.

The support mechanism 40 includes an auxiliary heat exchanger 50B
And a guide frame 42 bent substantially in a U-shape provided on the front side of the uppermost part of the main heat exchanger 50A above the holding frame 41. Consists of

The holding frame 41 and the guide frame 42 are provided in pairs at positions facing the left and right sides of the air purifier 13. The holding frame 41 is open on the front side, and the guide frame 42 is open on the lower side. The guide frame 42 has a longer portion than the holding frame 41, and the interval between the portions gradually increases from the bent end to the open end.

On the other hand, the upper part of the air purifier 13 is an air purifier 13a which substantially performs an air purifying action, and the lower part is a handle 13b. These air purifiers 13a
Two pin portions 43 and 44 are provided on both left and right sides of the handle 13b.

Therefore, as shown in FIG. 5A, the air cleaner 13 is supported on the front surface of the main heat exchanger 50A because the pin portion 44 of the handle portion 13b is fitted into the holding frame 41 and The pin portion 43 of the air purifying portion 13a is
Is in a state of being fitted to the bent end of.

To remove the air purifier 13 for maintenance, the front panel 2 is opened, and the handle 13 is removed.
Pull out b toward you. The pin portion 44 of the handle portion 13b is released from the holding frame 41 and becomes free, and the air purifier 13 itself is in an oblique posture.

When the air purifier 13 is shifted downward as it is, the air purifier 13 is moved as shown by a two-dot chain line in FIG.
The pin portion 43 a is almost at the open end of the guide frame 42, and the air cleaner 13 can be extracted from the support mechanism 40. At this time, since the air purifier 13 is in an oblique posture, it does not interfere with the auxiliary heat exchanger 50B below this.

In order to attach the air purifier 13 to the support mechanism 40 after the maintenance, the air purifier 13 is first set to a very oblique state as shown by a solid line in FIG. Is inserted into the guide frame 42, and the air cleaner 13 is pulled upward as it is.

As shown by the two-dot chain line in FIG. 5, when the pin 43 of the air cleaning section 13a comes into contact with the bent end of the guide frame 42, the handle 13b is pressed against the main heat exchanger 50A. Inevitably, the pin portion 44 of the handle portion 13b is
The air purifier 13 is mounted and supported. At this time, the air purifier 13 also uses the auxiliary heat exchanger 50B.
It does not interfere at all and therefore has good operability.

FIG. 6 schematically illustrates the indoor unit described above with reference to FIG. 1, and specifically illustrates a piping system in the indoor heat exchanger 5. The indoor heat exchanger 5 and the other components are the same as those described with reference to FIG. 1 as they are, and thus the same numbers are given and the new description is omitted.

In the indoor heat exchanger 5, the front and rear auxiliary heat exchanger sections 5c and 5d are connected in series, and the front and rear heat exchanger sections 5a and 5b are connected in series. The auxiliary heat exchanger 50B and the main heat exchanger 50A are connected in series. An electronic expansion valve 23 as a refrigerant expansion device is provided upstream of the indoor heat exchanger 5 in the dehumidifying operation mode and the cooling operation mode.

The flow of the refrigerant in the indoor heat exchanger 5 in the dehumidifying and cooling operation modes will be described in detail. The refrigerant enters the rear auxiliary heat exchanger section 5d from the electronic expansion valve 23, exits therefrom, and then moves to the front side. Jump to the auxiliary heat exchanger section 5c. Next, it is guided to the front heat exchanger part 5a and rises from the lower end part in the front row to the upper end part and enters the rear heat exchanger part 5b. In the rear heat exchanger section 5b, it is guided from the rear row upper end to the lower end, further U-turns to the front row upper end, flows again to the rear row lower end of the front heat exchanger section 5a, and exits outside.

In the dehumidifying operation mode, the refrigerant is guided from the rear auxiliary heat exchanger section 5d to the front auxiliary heat exchanger section 5c through the auxiliary heat exchanger 50B, and is set in the supercooled state by setting the throttle amount of the electronic expansion valve 23. Become. Further, the main heat exchanger 50A is guided from the front heat exchanger section 5a to the rear heat exchanger section 5b to be super-heated.
It becomes a heat state. Therefore, the indoor air sucked into the unit main body 1 is completely and completely dehumidified, and is blown back into the room.

Even in the cooling operation mode, the main heat exchanger 50A
The refrigeration cycle circuit is configured so that the refrigerant is guided to the auxiliary heat exchanger 50B earlier than the auxiliary heat exchanger 50B.
The cooling effect of B can be increased, and the cooling effect can be improved.

Further, since the electronic expansion valve 23 provided on the upstream side of the auxiliary heat exchanger 50B is narrowed down more in the dehumidifying operation mode than in the cooling operation mode, the evaporating action is performed only by the auxiliary heat exchanger 50B. Main heat exchanger 5
At 0A, it is in super heat state and the main heat exchanger 50A
To a temperature close to room temperature. For this reason, the auxiliary heat exchanger 50
The air that has been cooled and dehumidified in B is heated in the main heat exchanger 50A and blown out into the indoor space, so that a decrease in room temperature is minimized.

[0064]

As described above, according to the present invention, by arranging the auxiliary heat exchanger on the lower front side of the main heat exchanger where the wind speed is the highest, the auxiliary heat exchanger is dehumidified especially in the dehumidifying operation mode. A heat exchanger is used to improve the dehumidification performance by increasing the amount of dehumidification. In addition, the drain generated in the auxiliary heat exchanger does not flow to the main heat exchanger but immediately flows to the drain pan to prevent re-evaporation in the main heat exchanger, thereby improving heat exchange performance. Play.

[Brief description of the drawings]

FIG. 1 is a sectional view of an indoor unit of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle circuit according to the embodiment.

FIG. 3 is a diagram schematically illustrating an indoor unit and illustrating a flow of a refrigerant according to the embodiment.

FIG. 4 is a configuration diagram of a refrigeration cycle circuit according to the embodiment.

FIG. 5 is a diagram for explaining an attaching / detaching operation of the air purifier according to the embodiment.

FIG. 6 is a diagram schematically illustrating an indoor unit and illustrating a flow of a refrigerant according to the embodiment.

[Explanation of symbols]

 Reference Signs List 1 unit body, 5 indoor heat exchanger, 7 indoor blower, 50A main heat exchanger, 6a front drain pan, 6b rear drain pan, 50B auxiliary heat exchanger, 23 electronic expansion valve, 40 support mechanism.

Claims (8)

[Claims] 1. A unit body provided with a suction port on a front panel, and a blow port provided below the suction port; a main heat exchanger disposed in the unit body so as to face the suction port; A blower disposed behind the main heat exchanger; a drain pan disposed below the main heat exchanger; and a dehumidifier disposed immediately above the drain pan and on a lower front side of the main heat exchanger. An indoor unit for an air conditioner, comprising: an auxiliary heat exchanger that supercools a refrigerant in an operation mode. 2. The air conditioning system according to claim 1, wherein in the cooling operation mode, the refrigeration cycle circuit is configured to guide the refrigerant to the auxiliary heat exchanger before the main heat exchanger. Indoor unit of the machine. 3. A refrigerant expansion device is provided upstream of the auxiliary heat exchanger in a cooling operation mode and a dehumidification operation mode,
The indoor unit of an air conditioner according to claim 2, wherein the refrigerant expansion device is throttled more greatly in a dehumidification operation mode than in a cooling operation mode. 4. An auxiliary refrigerant throttle device is interposed between the main heat exchanger and the auxiliary heat exchanger. The auxiliary refrigerant throttle device has a condensing function when the main heat exchanger is in a heating dehumidifying operation mode. The indoor unit of an air conditioner according to claim 1, wherein the auxiliary heat exchanger is throttled to perform a cooling action. 5. An air purifier is disposed on the front side of the main heat exchanger and above the auxiliary heat exchanger, and interferes with the auxiliary heat exchanger on the front side of the main heat exchanger of the unit body. The indoor unit for an air conditioner according to claim 1, further comprising a support means for detachably supporting the air purifier without performing. 6. A unit body provided with a suction port on a front panel, and a blow-out port provided below the suction port, and a substantially reverse view in a side view disposed in the unit body so as to face the suction port. A main heat exchanger formed in a V-shape and a blower arranged near the main heat exchanger; a front drain pan and a rear drain pan arranged below a front part and a rear part below the main heat exchanger; A pair of auxiliary heat exchangers disposed in front of the heat exchanger and on the lower front surface side and the rear upper surface side, respectively, so as to supercool the refrigerant in the dehumidifying operation mode. Indoor unit. 7. The air conditioning system according to claim 6, wherein in the cooling operation mode, the refrigeration cycle circuit is configured to guide the refrigerant to the auxiliary heat exchanger before the main heat exchanger. Indoor unit of the machine. 8. A refrigerant expansion device is provided upstream of the auxiliary heat exchanger in the cooling operation mode, and the refrigerant expansion device is throttled more in the dehumidification operation mode than in the cooling operation mode. Item 7. An indoor unit for an air conditioner according to Item 7.