JPH05203274A - Air conditioning apparatus - Google Patents

Abstract

PURPOSE:To provide an air conditioning apparatus in which a heat exchanger in a duct is not varied from a refrigerant evaporator to a refrigerant condenser even if dehumidification is switched to a room heating and the air of high humidity is not diffused in a room. CONSTITUTION:An upstream side heat exchanger 18 is connected between a downstream side heat exchanger 19 and an outdoor heat exchanger 21 via a refrigerant piping 27 in a refrigerating cycle 17. The cycle 17 has a bypass refrigerant passage 34 for bypassing the exchanger 18 and a dehumidifying pressure reducing unit 25. The refrigerant of the exchanger 18 is bypassed at the time of room heating. Thus, the exchanger 18 performs a function as a refrigerant evaporator at the time of dehumidifying but since it is paused at the time of room heating, drain water adhered to the exchanger 18 is not evaporated at the time of dehumidifying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner capable of at least heating operation and dehumidifying operation by a refrigeration cycle.

[0002]

BACKGROUND OF THE INVENTION The inventors of the present invention have provided heat exchangers upstream and downstream of a duct that sends an air flow into a vehicle, using the upstream heat exchanger as a refrigerant evaporator, and the downstream heat exchanger. A technique for dehumidifying the room by using it as a refrigerant condenser has been proposed (not a known technique). The outline of this technology is
This will be described with reference to FIGS. 4 and 5. The refrigeration cycle 100 is
The upstream heat exchanger 101 and the downstream heat exchanger 10 described above.
In addition to 2, the outdoor heat exchanger 103 that absorbs heat during heating or discharges heat during heating is provided. And
In the refrigeration cycle 100, the upstream heat exchanger 101 is arranged between the downstream heat exchanger 102 and the outdoor heat exchanger 103 (FIG. 4), the upstream heat exchanger 101 and the outdoor heat exchanger 103. There was a device in which the downstream heat exchanger 102 was placed between the two (Fig. 5). The refrigeration cycle 100 switches the direction of the refrigerant discharged from the refrigerant compressor and the flow path of the refrigerant to perform indoor cooling operation, heating operation, and dehumidifying operation. Specifically, in the refrigeration cycle 100 of FIG. 4 in which the upstream heat exchanger 101 is arranged between the downstream heat exchanger 102 and the outdoor heat exchanger 103, the cooling operation is performed as shown by → C in the drawing. The refrigerant discharged from the machine is used as the outdoor heat exchanger 103.
The refrigerant is flowed in the order of the pressure reducing device 104, the upstream heat exchanger 101, and the downstream heat exchanger 102. During heating operation, the refrigerant discharged from the refrigerant compressor is transferred to the downstream heat exchanger as indicated by H in the figure. Vessel 102 → upstream heat exchanger 101 → pressure reducing device 104 →
Refrigerant is caused to flow in the order of the outdoor heat exchanger 103, and during the dehumidifying operation and the heating operation, the refrigerant discharged from the refrigerant compressor is transferred to the downstream heat exchanger 102 → the decompressor 105 → the upstream heat as shown by D in the figure. Exchanger 101 (→ Outdoor heat exchanger 10 in some cases
Refrigerant is caused to flow in the order of 3). Further, in the refrigeration cycle 100 of FIG. 5 in which the downstream heat exchanger 102 is arranged between the upstream heat exchanger 101 and the outdoor heat exchanger 103, during the cooling operation, the refrigerant compression is performed as indicated by → C in the drawing. The refrigerant discharged from the machine is converted into the outdoor heat exchanger 103, the pressure reducing device 104, and the downstream heat exchanger 10.
Refrigerant is caused to flow in the order of 2 → upstream side heat exchanger 101, and during heating operation, as shown by → H in the figure, the refrigerant discharged from the refrigerant compressor is transferred to the upstream side heat exchanger 101 → the downstream side heat exchanger 102 → Refrigerant is caused to flow in the order of the pressure reducing device 104 and the outdoor heat exchanger 103,
During the dehumidifying operation, as shown by → D in the figure, the refrigerant discharged from the refrigerant compressor is changed to (in some cases, the outdoor heat exchanger 103 →).
The refrigerant flows in the order of the downstream heat exchanger 102, the pressure reducing device 105, and the upstream heat exchanger 101.

[0003]

The following Table 1 shows the functions of the upstream heat exchanger 101 and the downstream heat exchanger 102 in each operation of the refrigerating cycle 100 described above.

[Table 1] As can be seen from Table 1 above, in the refrigeration cycle 100 described in the above technique, when the cooling operation is switched to the heating operation, the upstream heat exchanger 101 changes from the refrigerant evaporator to the refrigerant condenser. Further, when the cooling operation is switched to the dehumidifying operation, the downstream heat exchanger 102 changes from the refrigerant evaporator to the refrigerant condenser. Further, when the dehumidifying operation is switched to the heating operation, the upstream heat exchanger 101 changes from the refrigerant evaporator to the refrigerant condenser. When the refrigerant evaporator is changed to the refrigerant condenser, the drain water attached to the refrigerant evaporator is evaporated due to the change to the refrigerant condenser and is blown out from the duct into the room. In particular,
In a small room such as an automobile, the window glass may become cloudy. Note that there is almost no switching from cooling to heating operation and switching from cooling to dehumidification operation. However, since switching from dehumidification to heating operation is usually possible, a refrigeration cycle in which the heat exchanger in the duct does not change from the refrigerant evaporator to the refrigerant condenser even when switching from dehumidification to heating operation is desired.

An object of the present invention is to provide an air conditioner in which the heat exchanger in the duct does not change from a refrigerant evaporator to a refrigerant condenser even when switching from dehumidification to heating operation.

[0005]

In order to achieve the above object, the air conditioner of the present invention employs the following technical means. The air conditioner of the present invention includes a duct that forms an air passage to the room, a blower that sends air to the room through the duct, and a heat of the air and the refrigerant that are arranged inside the duct and that is sent to the room. An upstream heat exchanger for exchanging, inside the duct, disposed downstream of the upstream heat exchanger, a downstream heat exchanger for exchanging heat between air and refrigerant sent to the room,
An outdoor heat exchanger arranged outside the duct for exchanging heat between outdoor air and a refrigerant, a bypass refrigerant passage through which the refrigerant bypasses the upstream heat exchanger, and the upstream heat exchange during dehumidifying operation. Used as a refrigerant evaporator, using the downstream heat exchanger as a refrigerant condenser, the refrigerant bypasses the upstream heat exchanger by the bypass refrigerant passage during heating operation, the downstream heat exchanger, It is provided to be used as a refrigerant condenser and the outdoor heat exchanger to be used as a refrigerant evaporator.

[0006]

When the dehumidifying operation is performed, the upstream heat exchanger functions as a refrigerant evaporator, and the downstream heat exchanger functions as a refrigerant condenser. Therefore, the air flowing in the duct is deprived of heat when passing through the upstream heat exchanger, and is cooled,
Dehumidified. The dry air cooled by the upstream heat exchanger is heated when passing through the downstream heat exchanger and blown out into the room to dehumidify the room. When the dehumidifying operation is switched to the heating operation, the bypass refrigerant passage causes the refrigerant to bypass the upstream heat exchanger. The downstream heat exchanger functions as a refrigerant condenser, and the outdoor heat exchanger functions as a refrigerant evaporator. Therefore, the air flowing in the duct is heated when passing through the downstream heat exchanger and is blown out into the room to heat the room.

[0007]

As described above, the air conditioner of the present invention does not switch the upstream heat exchanger from the refrigerant evaporator to the refrigerant condenser even when the dehumidifying operation is switched to the heating operation. Therefore, even if the dehumidifying operation is switched to the heating operation, the drain water adhering to the upstream heat exchanger does not evaporate during the dehumidifying operation, so that it is possible to eliminate the problem that high-humidity air is blown into the room.

[0008]

Next, the air conditioner of the present invention will be described based on an embodiment applied to an automobile air conditioner. [Configuration of Embodiment] FIGS. 1 and 4 show an embodiment of the present invention. FIG. 1 is a refrigerant circuit diagram of an air conditioner, and FIG. 2 is a schematic configuration diagram of an indoor unit of the air conditioner. The indoor unit 1 includes a duct 2 that forms an air passage for sending air toward the passenger compartment. The duct 2 is arranged in the vehicle compartment, and one end of the duct 2 is connected to a blower 4 having an inside / outside air switching unit 3. The inside / outside air switching means 3 includes an inside air inlet 5 that communicates with the inside of the vehicle and introduces air inside the vehicle (inside air), and an outside air inlet 6 that communicates with the outside of the vehicle and introduces air outside the vehicle (outside air). Equipped with. Then, the inside / outside air switching means 3
Includes an inside / outside air switching damper 7, and the inside / outside air switching damper 7 can switch the air guided into the duct 2 between the inside air and the outside air. The blower 4 is composed of a fan case 8, a fan 9 and a motor 10. When the motor 10 is energized, the fan 9 rotates and sends the inside air or the outside air to the room through the duct 2.

At the other end of the duct 2, there is formed an air outlet for blowing out the air passing through the duct 2 toward each part in the passenger compartment. This air outlet is a ventilation air outlet 11 that mainly blows cold air toward the occupant's head and chest, a foot air outlet 12 that mainly blows warm air toward the occupant's feet, and a hot air outlet mainly toward the window glass. Defroster outlet 1 that blows out the wind
3 and 3. A ventilation damper 14, a foot damper 15, and a defroster damper 16 that control the air flow to each outlet are provided in the duct 2 in an air passage communicating with each outlet.

Further, in the duct 2, an upstream heat exchanger 18 of the refrigeration cycle 17 for exchanging heat between the refrigerant and air is arranged. The upstream heat exchanger 18 of the present embodiment is provided so that all the air in the duct 2 passes through. Downstream of the upstream heat exchanger 18, a downstream heat exchanger 19 of the refrigeration cycle 17 that exchanges heat between the refrigerant and air is arranged. Like the upstream heat exchanger 18, the downstream heat exchanger 19 of the present embodiment is provided so that all the air in the duct 2 passes through. An auxiliary heater 20 is provided downstream of the downstream heat exchanger 19. The auxiliary heater 20 is an electric heater such as a PTC heater and heats the air flowing in the duct 2 by generating heat according to the amount of energization.

The refrigerating cycle 17 shown in this embodiment is an accumulator cycle and is an outdoor heat exchanger 21, a refrigerant compressor 22 and a cooling decompression in addition to the upstream heat exchanger 18 and the downstream heat exchanger 19 described above. Device 23, decompression device 2 for heating
4, a dehumidifying decompression device 25, an accumulator 26, and a flow path switching means for switching the flow direction of the refrigerant, which are connected by a refrigerant pipe 27. The outdoor heat exchanger 21 performs heat exchange between the air outside the vehicle compartment and the refrigerant outside the duct 2, and the upstream heat exchanger 18 is connected to the downstream heat exchanger 19 by the refrigerant pipe 27. .. The outdoor heat exchanger 21 is provided at a position where traveling wind generated by traveling of the vehicle is hit. The refrigerant compressor 22 sucks, compresses, and discharges the refrigerant, and is driven by an electric motor (not shown). The refrigerant compressor 22 is arranged, for example, integrally with an electric motor in a sealed case. The rotation speed of the electric motor is variable continuously or stepwise by inverter control, and the refrigerant discharge capacity of the refrigerant compressor 22 changes according to the change of the rotation speed of the electric motor. In this embodiment, the outlet temperature is controlled by changing the capacity of the refrigerant compressor 22 due to the change in rotation speed. The cooling decompression device 23 and the heating decompression device 24 are fixed-throttle capillary tubes provided in a refrigerant pipe 27 connecting the upstream heat exchanger 18 and the outdoor heat exchanger 21, and the cooling decompression device 23 is upstream. It is provided on the side heat exchanger 18 side, and the heating decompression device 24 is provided on the outdoor heat exchanger 21 side. Then, the cooling decompression device 23 decompresses and expands the refrigerant flowing from the outdoor heat exchanger 21 to the upstream heat exchanger 18, and the heating decompression device 24.
The refrigerant flowing into the outdoor heat exchanger 21 is decompressed and expanded.
The dehumidifying decompression device 25 is a fixed-throttle capillary tube provided in the refrigerant pipe 27 that connects the upstream heat exchanger 18 and the downstream heat exchanger 19, and is used from the downstream heat exchanger 19 to the upstream side during dehumidification operation. The refrigerant flowing into the heat exchanger 18 is decompressed and expanded. The accumulator 26 stores the excess refrigerant in the refrigeration cycle, sends the gas-phase refrigerant to the refrigerant compressor 22, and prevents the liquid refrigerant from being sucked into the refrigerant compressor 22.

The refrigerant flow path switching means switches the flow direction of the refrigerant between the cooling operation, the heating operation and the dehumidifying operation. Specifically, a four-way valve 28 that switches the discharge direction of the refrigerant compressor 22 between the cooling operation and another operation, and a check valve 29 that bypasses the heating decompression device 24 and the dehumidification decompression device 25 during the cooling operation. , 30, a check valve 31 for bypassing the cooling pressure reducing device 23 during the heating operation, a first electromagnetic opening / closing valve 32 which is opened only during the heating operation and bypasses the upstream heat exchanger 18 and the dehumidifying pressure reducing device 25, the dehumidifying operation A second electromagnetic opening / closing valve 33 is provided for bypassing the refrigerant that is opened only at a time and flows out of the upstream heat exchanger 18 to the refrigerant compressor 22. The refrigerant pipe 27 that bypasses the upstream heat exchanger 18 and the dehumidifying decompression device 25 via the first electromagnetic opening / closing valve 32 is a bypass refrigerant passage according to the present invention that bypasses the upstream heat exchanger 18 during heating operation. 34.

The flow path switching means switches the flow of the refrigerant as follows in accordance with the cooling operation, the heating operation and the dehumidifying operation. During the cooling operation, the refrigerant discharged from the refrigerant compressor 22 is supplied with the four-way valve 28 → the outdoor heat exchanger 21 → the cooling decompressor 23 → the upstream heat exchanger 18 → the downstream heat exchanger 1
9 → four-way valve 28 → accumulator 26 → refrigerant compressor 22
Flow in that order (see arrow C in the figure). During the heating operation, the refrigerant discharged from the refrigerant compressor 22 is transferred to the four-way valve 28 → the downstream heat exchanger 19 → the bypass refrigerant passage 34 → the heating decompression device 24 →
Outdoor heat exchanger 21 → four-way valve 28 → accumulator 26 →
It flows in order of the refrigerant compressor 22 (see arrow H in the figure). During the dehumidifying operation, the refrigerant discharged from the refrigerant compressor 22 is supplied to the four-way valve 28.
-> Downstream heat exchanger 19-> Dehumidifying decompression device 25-> Upstream heat exchanger 18-> Accumulator 26-> Refrigerant compressor 22 (see arrow D in the figure).

The upstream heat exchanger 18 during each of the above operations
The function of the downstream heat exchanger 19 is shown in Table 2 below.

[Table 2]

[Operation of Embodiment] Next, the operation of switching from the dehumidifying operation to the heating operation according to the present invention will be briefly described. When the dehumidifying operation is set by the user, the blower 4 sucks the outside air or the inside air selected by the inside / outside air switching means 3 into the duct 2, and the upstream side heat exchanger 18, the downstream side heat exchanger 19, and the auxiliary heater. It blows out into the vehicle interior from the selected outlet through 20. Refrigeration cycle 1 during dehumidification operation
The high-temperature high-pressure refrigerant discharged from the refrigerant compressor 22 is guided to the downstream heat exchanger 19 by the four-way valve 28. Here, the refrigerant exchanges heat with the air flowing in the duct 2, heats the air in the duct 2, and liquefies and condenses in the downstream heat exchanger 19. The liquefied refrigerant is used in the dehumidifying decompression device 25.
When passing through, it expands under reduced pressure and becomes a mist at low temperature and low pressure. The atomized refrigerant flows into the upstream heat exchanger 18, takes heat from the air flowing in the duct 2 and evaporates. Then, the vaporized refrigerant is re-sucked into the refrigerant compressor 22 via the second electromagnetic opening / closing valve 33 and the accumulator 26. When the air sucked into the duct 2 passes through the upstream heat exchanger 18, the vapor in the air is condensed due to the decrease in temperature and adheres to the upstream heat exchanger 18. After that, the downstream heat exchanger 1
Since the air is heated when passing through 9, the air in which the humidity in the air is significantly reduced is blown into the vehicle interior to perform good dehumidification in the vehicle interior.

When the user switches from the dehumidifying operation to the heating operation, the liquid refrigerant liquefied and condensed in the downstream heat exchanger 19 passes through the bypass refrigerant passage 34 and the upstream heat exchanger 1
Bypass 8. The liquefied refrigerant that has bypassed the upstream heat exchanger 18 expands under reduced pressure when passing through the heating decompression device 24, and becomes a low-temperature low-pressure mist. This atomized refrigerant flows into the outdoor heat exchanger 21, takes heat from the outside air and evaporates,
It is re-sucked into the refrigerant compressor 22 via the four-way valve 28 and the accumulator 26. The air sucked into the duct 2 is heated by the high-temperature refrigerant when passing through the downstream heat exchanger 19, and is blown into the vehicle interior to heat the vehicle interior.

[Effects of Embodiment] In the present embodiment, as described above, even when the dehumidifying operation is switched to the heating operation, the upstream heat exchanger 18 is switched from the refrigerant evaporator to the idle state and the refrigerant is condensed. It does not switch to a vessel. For this reason,
Even if the dehumidifying operation is switched to the heating operation, the drain water adhering to the upstream heat exchanger 18 does not evaporate during the dehumidifying operation, so that there is no problem that humid air is blown into the room and the window glass of the vehicle becomes cloudy. You can When the cooling operation is switched to the dehumidifying operation, the downstream heat exchanger 19 is switched from the refrigerant evaporator to the refrigerant condenser. However, since the window glass is not normally fogged during the cooling operation, the cooling operation is switched to the dehumidifying operation. If needed, almost never. That is, when the cooling operation is switched to the dehumidifying operation, the downstream heat exchanger 19 is switched from the refrigerant evaporator to the refrigerant condenser.
There are not many practical defects. Further, when the cooling operation is switched to the heating operation, the downstream side heat exchanger 19 is switched from the refrigerant evaporator to the refrigerant condenser. However, as in the technique shown in the background of the invention, two heat exchangers on the upstream side and the downstream side are exchanged. Compared with both switching from the refrigerant evaporator to the refrigerant condenser, only one downstream heat exchanger 19 is switched (in this case, the heating capacity may be gradually increased). Most of the drain water is on the upstream heat exchanger 18
The drain water does not adhere much to the downstream heat exchanger 19. Therefore, the humidity of the blown air can be suppressed lower in the present embodiment than in the technique shown in the background of the invention. In addition, there is almost no case where the cooling operation is switched to the heating operation, and there are not many practical problems. The air conditioner of the present embodiment does not use a heat source other than the air conditioner, and thus is suitable for a vehicle that does not have a surplus heat source such as an electric vehicle.

[Other Embodiments] FIG. 3 is a refrigerant circuit diagram showing another embodiment. In the above embodiment, the downstream heat exchanger 1
9 shows the refrigeration cycle 17 in which the upstream heat exchanger 18 is connected to the outdoor heat exchanger 21 by the refrigerant pipe 27. However, in this embodiment, the upstream heat exchanger 18 and the outdoor heat exchanger 21 are connected to each other. The refrigeration cycle 17 in which the downstream heat exchanger 19 is connected by the refrigerant pipe 27 during the period is shown. Further, in the above embodiment, an example in which the cooling decompression device (see the above embodiment) and the heating decompression device (see the above embodiment) are provided respectively is shown, but in this embodiment, the common decompression device 35 is common. And

The flow path switching means of this embodiment is a four-way valve 28 that switches the discharge direction of the refrigerant compressor 22 between the cooling operation and other operations, and is opened during the cooling operation and the heating operation to decompress the dehumidifying device. Third solenoid on-off valve 3 for bypassing 25
6. Provided with check valves 37 and 38 for bypassing the upstream heat exchanger 18 during the heating operation, and a fourth electromagnetic opening / closing valve 39 which is opened only during the dehumidifying operation to bypass the outdoor heat exchanger 21 and the common pressure reducing device 35. It becomes. And the flow path switching means is
The refrigerant flow is switched as follows depending on the cooling operation, the heating operation, and the dehumidifying operation. During the cooling operation, the refrigerant discharged from the refrigerant compressor 22 is supplied with the four-way valve 28, the outdoor heat exchanger 21, the common pressure reducing device 35, the downstream heat exchanger 19, and the third heat exchanger.
The electromagnetic on-off valve 36, the upstream heat exchanger 18, the four-way valve 28, the accumulator 26, and the refrigerant compressor 22 are passed in this order (see arrow C in the figure). During the heating operation, the refrigerant discharged from the refrigerant compressor 22 is supplied with the four-way valve 28 → the bypass refrigerant passage 34 → the downstream heat exchanger 19 → the common pressure reducing device 35 → the outdoor heat exchanger 21 → the four-way valve 28 → the accumulator 26 → the refrigerant. Flow in the order of the compressor 22 (see arrow H in the figure). During the dehumidifying operation, the refrigerant compressor 2
The discharged refrigerant of 2 is transferred from the four-way valve 28 to the fourth solenoid on-off valve 39.
-> Downstream heat exchanger 19-> Dehumidifying decompression device 25-> Upstream heat exchanger 18-> Four-way valve 28-> Accumulator 26-> Refrigerant compressor 22 (see arrow D in the figure).

[Modification] When the dehumidifying operation is switched to the heating operation, the heating capacity may be gradually increased. In the above-described embodiment, the example in which the outdoor heat exchanger is provided so as to bypass the refrigerant during the dehumidifying operation is shown, but the refrigerant may be passed through the outdoor heat exchanger. In the above example, the upstream heat exchanger (downstream heat exchanger) and the outdoor heat exchanger are connected in series by the refrigerant pipe, but they may be connected in parallel if necessary.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner (example).

FIG. 2 is a schematic configuration diagram of an indoor unit.

FIG. 3 is a refrigerant circuit diagram of the air conditioner (another embodiment).

FIG. 4 is a refrigerant circuit diagram of the air conditioner (proposed technology).

FIG. 5 is a refrigerant circuit diagram of the air conditioner (another proposed technique).

[Explanation of symbols]

 2 Duct 4 Blower 17 Refrigeration cycle 18 Upstream heat exchanger 19 Downstream heat exchanger 21 Outdoor heat exchanger 27 Refrigerant pipe 34 Bypass refrigerant passage

Claims (1)

[Claims] 1. (a) a duct forming an air passage to the room; (b) a blower for sending air to the room through the duct; (c) (c-1) disposed inside the duct. An upstream heat exchanger for exchanging heat between the air sent to the room and the refrigerant, (c-2), inside the duct, disposed downstream of the upstream heat exchanger, and sent to the room. A downstream heat exchanger for exchanging heat with the refrigerant, (c-3) an outdoor heat exchanger arranged outside the duct for exchanging heat between the outdoor air and the refrigerant, and (d) the upstream side. A bypass refrigerant passage through which the refrigerant bypasses the heat exchanger, and (e) the upstream heat exchanger is used as a refrigerant evaporator during the dehumidifying operation, and the downstream heat exchanger is used as a refrigerant condenser, (f) During the heating operation, the bypass refrigerant passage allows the refrigerant to bypass the upstream heat exchanger and cool the downstream heat exchanger. Use as vessel, an air conditioning apparatus, characterized in that provided for use as a refrigerant evaporator to the outdoor heat exchanger.