JP5127858B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a vehicle air conditioner mounted on a vehicle such as a railway.

  2. Description of the Related Art Conventionally, a vehicle air conditioner including a refrigerant circuit in which a first heat exchanger, a compressor, a second heat exchanger, and an expansion valve are sequentially connected in a ring shape with piping has been proposed. . Among them, there is a form in which an independent refrigerant circuit is provided. As such, a discharge fan that sends wind toward the first heat exchanger to the outside of the vehicle is disposed at a substantially central position in the vehicle width direction, and on both sides of the vehicle width direction of the vehicle with respect to the exhaust fan. Two first heat exchangers are respectively disposed, and an intake fan that sends wind toward the second heat exchanger is disposed substantially in the center in the vehicle width direction, and is disposed in the vehicle width direction of the vehicle with respect to the intake fans. There has been proposed a form in which two second heat exchangers are arranged on both sides (for example, Patent Document 1).

  Various heat exchangers for vapor compression refrigeration systems using carbon dioxide as a refrigerant in a high pressure state without phase change have been proposed. Among them, in order to improve the heat transfer performance of the heat exchanger, there is one that improves the thermal efficiency of the vapor compression refrigeration apparatus by improving the refrigerant temperature on the outlet side of the radiator. This heat exchanger is a heat exchanger composed of a plurality of rows so that the number of refrigerant paths communicating the heat exchangers in each row decreases from the refrigerant inlet side to the outlet side of the heat exchanger. In addition, by changing the number of the outlet side and the inlet side of the refrigerant path of the heat exchanger, the flow rate suitable for heat exchange of the refrigerant flowing in the heat exchanger according to the increase in refrigerant density accompanying the refrigerant temperature level Therefore, heat exchange efficiency can be improved by maintaining the temperature (for example, Patent Document 2).

JP 2006-116981 A (FIG. 1) JP 2000-304380 A (FIG. 1)

The number of the heat transfer tubes provided in the heat exchanger of the vehicle air conditioner in the vertical direction is set to be larger than the number in the row direction, which is a direction orthogonal to the step direction. Therefore, when a refrigerant that is in a supercritical state on the high pressure side, such as carbon dioxide, is used for the vehicle air conditioner, it is necessary to increase the thickness of the refrigerant piping, and the vertical compactness of the vehicle air conditioner is required. There was a risk of damage.
Further, the conventional vehicle air conditioner is not installed so that the flow direction of the refrigerant flowing in the heat transfer tube and the flow direction of the heat transfer medium flowing outside the heat transfer tube are opposed to each other. There was a possibility that the heat exchange efficiency would deteriorate.

  The present invention has been made in order to solve the above-described problems, and a first object is to provide a compact vehicle air conditioner. The second object is to improve the heat exchange efficiency of the vehicle air conditioner.

A vehicle air conditioner according to the present invention includes a compressor, a first heat exchanger, a throttling device, and a second heat exchanger, which are connected in an annular shape via a refrigerant pipe to constitute a refrigeration cycle. A vehicle air conditioner equipped with a circuit is provided with an exhaust fan and two sets of refrigerant circuits provided at the center in the vehicle width direction, and is supercritical in the high pressure section of the two sets of refrigerant circuits. The first heat exchangers of the two refrigerant circuits are provided side by side with an exhaust fan in the vehicle width direction, suck the heat transfer medium from the side of the vehicle, and a plurality of flat plate fins are arranged in parallel And a plurality of heat transfer tubes provided in a row direction that is a direction perpendicular to the row direction and provided in a plurality of rows in a row direction that is a flow direction of the heat transfer medium. The number of the heat transfer tubes in the row direction is the number in the row direction. And the plurality of flat plate fins are provided so as to be orthogonal to the flow direction of the heat transfer medium, and the first heat exchanger includes the refrigerant flowing through the heat transfer tube and the heat When the second heat exchanger is functioning as an evaporator, the dew condensation water generated on the surface of the second heat exchanger is disposed between the first heat exchanger and the flow direction of the transmission medium. When the surface of the refrigerant pipe connecting between the expansion device and the length of the first heat exchanger in the vehicle width direction is defined as 1, the end of the first heat exchanger on the side of the vehicle from the end on the exhaust fan side is defined. In the direction of 0.6 to 0.8 in the direction of heading .

  The vehicle air conditioner according to the present invention is excellent in compactness and can improve heat exchange efficiency.

It is the schematic of the air conditioner for vehicles in embodiment of this invention. It is sectional drawing in dotted line AA of the air conditioner for vehicles shown in FIG. It is a perspective view of the heat exchanger tube and heat radiating member provided in the air conditioner for vehicles in an embodiment of the invention. It is the figure explaining the direction of the refrigerant | coolant which flows through the heat exchanger tube shown in FIG. 3, and the direction through which a to-be-heat-transfer medium (air) flows. In the cross-sectional view shown in FIG. 2, it is a figure showing the place which sprinkles water on a heat exchanger (radiator). It is a figure showing the refrigerant | coolant temperature change of the heat exchanger (radiator) in embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram of a vehicle air conditioner 100 according to an embodiment of the present invention. As shown in FIG. 1, a vehicle air conditioner 100 according to the present embodiment includes at least a refrigerant circuit 100a, a refrigerant circuit 100b, an exhaust fan 5, and an intake fan 6. These are one housing. It is stored in the body and installed outside the passenger compartment.

In the refrigerant circuit 100a, the compressor 1a, the first heat exchanger 2a, the expansion device 3a, and the second heat exchanger 4a are annularly connected via a refrigerant pipe to form a refrigeration cycle.
In the refrigerant circuit 100b, the compressor 1b, the first heat exchanger 2b, the expansion device 3b, and the second heat exchanger 4b are annularly connected via a refrigerant pipe to form a refrigeration cycle. .

The first heat exchanger 2a is installed on the right side in the vehicle width direction, and the first heat exchanger 2b is installed at the left end (the left and right may be reversed).
The first heat exchanger 2a is connected to two refrigerant pipes 7. One of the refrigerant pipes 7 is connected to the compressor 1a and the other is connected to the expansion device 3a.
Similarly, the first heat exchanger 2b is connected to two refrigerant pipes 7, one of which is connected to the compressor 1b and the other is connected to the expansion device 3b. Yes.

As shown in FIG. 1, the second heat exchanger 4 a is installed on the right side in the vehicle width direction, and the first heat exchanger 4 b is installed at the left end (the left and right may be reversed). Moreover, the 2nd heat exchanger 4a is installed in the front or back of the longitudinal direction of a vehicle with respect to the 1st heat exchanger 2a. Similarly, the 2nd heat exchanger 4b is installed in the front or back of the longitudinal direction of vehicles with respect to the 2nd heat exchanger 1b.
The second heat exchanger 4b is connected to two refrigerant pipes 7, one of which is connected to the compressor 1a, and the other is connected to the expansion device 3a.
Similarly, the first heat exchanger 2b is connected to two refrigerant pipes 7, one of which is connected to the compressor 1b and the other is connected to the expansion device 3b. Yes.

As shown in FIG. 1, the compressor 1a is connected to two refrigerant pipes 7, one of which is connected to the first heat exchanger 2a, and the other refrigerant pipe 7 is connected to the second refrigerant pipe 7. It is connected to the heat exchanger 4a.
Similarly, as shown in FIG. 1, the compressor 1b is connected to two refrigerant pipes 7, one of which is connected to the first heat exchanger 2b, and the other refrigerant pipe 7 is It is connected to the second heat exchanger 4b.

As shown in FIG. 1, the expansion device 3 a is connected to two refrigerant pipes 7. One of the refrigerant pipes 7 is connected to the first heat exchanger 2 a, and the other refrigerant pipe 7 is connected to the refrigerant pipe 7. It is connected to the second heat exchanger 4a.
Similarly, the expansion device 3b is connected to two refrigerant pipes, one of which is connected to the first heat exchanger 2a, and the other refrigerant pipe 7 is connected to the second heat exchanger 4b. It is linked with.

  As described above, the refrigerant circuit 100a and the refrigerant circuit 100b form independent ring configurations.

  The exhaust fan 5 is provided between the first heat exchanger 1a and the first heat exchanger 1b (the center in the vehicle width direction).

  The intake fan 6 is installed between the second heat exchanger 4b and the second heat exchanger 4b (in the center in the vehicle width direction) and at the front or rear of the exhaust fan 5 in the longitudinal direction of the vehicle.

  In the present embodiment, as the refrigerant circulating in the refrigerant circuit 100a or the refrigerant circuit 100b, for example, a critical pressure (a part where the refrigerant becomes high pressure at any position inside the refrigerant circuit 100a or the refrigerant circuit 100b) ( Carbon dioxide that is in a supercritical state of about 7.3 MPa or more is used.

  2 is a cross-sectional view taken along a dotted line AA of the vehicle air conditioner shown in FIG. Based on FIG. 2, the 1st heat exchanger 2a and the 1st heat exchanger 2b are demonstrated. As shown in FIG. 2, the first heat exchanger 2 a and the first heat exchanger 2 b are provided on both sides of the exhaust fan 5. The flow of air sucked and exhausted by the exhaust fan 5 is represented by arrows AR1 and AR2. Air is taken in from the side surface of the vehicle and discharged toward the exhaust fan 5. Thereafter, the air sucked into the exhaust fan 5 is discharged to the upper part of the exhaust fan 5.

  FIG. 3 is a perspective view of a heat transfer tube and a heat radiating member provided in the vehicle air conditioner according to the embodiment of the present invention. As shown in FIG. 3, the 1st heat exchanger 2a and the 1st heat exchanger 2b in this Embodiment are comprised with the heat exchanger tube 8 penetrated by the several flat heat radiating member 9 (plate fin). . In FIG. 3, although the shape of the heat radiating member 9 is a disk shape, it is not limited to it.

  As shown in FIG. 3, in this Embodiment, the heat exchanger tube 8 provided in the 1st heat exchanger 2a and the 1st heat exchanger 2b is the row | line | column which is the flow direction of a to-be-heat-transfer medium (air). A plurality of rows are provided in the direction AX2, and a plurality of rows are provided in the step direction AX1, which is a direction orthogonal to the row direction AX2. The first heat exchanger 2a and the first heat exchanger 2b are installed in the vehicle such that the number in the stage direction AX2 is smaller than the number in the column direction AX1.

  This is effective when there is a height restriction due to the presence of electric wires in the vertical direction, such as a railway vehicle. In this way, the first heat exchanger 2a and the first heat exchanger 2b are compact in the vertical direction, and can be easily installed in the vehicle even with the conventional housing size.

Below, the method to improve the heat exchange efficiency of the air conditioner 100 for vehicles in this Embodiment is demonstrated.
FIG. 4 is a diagram for explaining the direction of the refrigerant flowing through the heat transfer tube shown in FIG. 3 and the direction in which the heat transfer medium (air) flows. The first heat exchanger 2a and the first heat exchanger 1b face the direction of the refrigerant flowing in the heat transfer tube 8 indicated by the arrow FL1 and the direction of the heat transfer medium (air) indicated by the arrow FL2. Installed in the vehicle. This makes it possible to obtain a counterflow effect, and improves the heat transfer efficiency between the refrigerant and the heat transfer medium (air). Thereby, it can be set as a more efficient vehicle air conditioner.

Next, improvement in heat exchange efficiency will be described. In the following description, it is assumed that the second heat exchanger 4a and the second heat exchanger 4b function as an evaporator.
Condensed water (drain water) generated by condensation of moisture contained in the air passing through the second heat exchanger 4a (or the second heat exchanger 4b) is composed of the first heat exchanger 2a and the expansion device 3a ( Alternatively, the heat exchange efficiency of the vehicle air conditioner 100 is improved by spraying water directly to the refrigerant pipe 7 (represented by the dotted line PA3 in FIG. 1) connecting the first heat exchanger 2b and the expansion device 3b). can do. Thereby, the temperature of the refrigerant | coolant which goes to the expansion apparatus from the 1st heat exchanger 2a further falls. Thus, the temperature difference between the refrigerant flowing in the second heat exchanger 4a (or the second heat exchanger 4b) and the air taken in from the outside increases (the enthalpy difference increases), and the vehicle air conditioner The heat exchange efficiency of 100 can be improved (cooling performance is improved).

  FIG. 5 is a diagram illustrating locations (watering location PA1 and watering location PA2) where water is sprayed to each of the first heat exchanger 2a and the first heat exchanger 2b (heat radiator) in the cross-sectional view shown in FIG. . In the present embodiment, the dew condensation water (drain water) generated by condensation of moisture contained in the air passing through the second heat exchanger 4a (or the second heat exchanger 4b) is the second heat exchanger. When the length in the vehicle width direction of 4a (or the second heat exchanger 4b) is defined as 1, 0.6 in the direction from the end on the intake fan side toward the vehicle side surface in the second heat exchanger. It is possible to supply in the range of ~ 0.8. Thereby, as will be described later with reference to FIG. 6, the heat exchange efficiency can be improved.

  FIG. 6 is a diagram illustrating a change in refrigerant temperature of the heat exchanger (heat radiator) in the embodiment of the present invention. FIG. 6 shows that when the length of the first heat exchanger 2a (or the first heat exchanger 2b) in the vehicle width direction is defined as 1, the vehicle starts from the end on the intake fan side of the first heat exchanger. In the range of 0.6 to 0.8 in the direction toward the side, the specific heat of the refrigerant is large and the temperature change is small. The temperature of the refrigerant is lowered by supplying condensed water having a low temperature to this portion and promoting cooling. Thereby, the temperature difference between the refrigerant and the heat transfer medium becomes larger. Therefore, a larger counter flow effect can be obtained, and the heat exchange efficiency can be improved.

  In the present embodiment, it is desirable that the dew condensation water can be supplied to the entire first heat exchanger 2a (or the first heat exchanger 2b). However, the vehicle air conditioner 100 may have difficulty securing the amount of condensed water. Therefore, water is intensively supplied to the place where the above water supply method is most effective (the place where the specific heat of the refrigerant is high), and the refrigerant temperature can be lowered efficiently even with a small amount of condensed water. Is possible.

  As described above, in the present embodiment, the heat exchanger is arranged so that more heat transfer tubes 8 are arranged in the direction of the arrow AX2 than in the direction of the arrow AX1, so that the vertical direction of the air conditioner is made compact. The machine 100 can be obtained. Moreover, heat exchange efficiency can be improved by making the refrigerant | coolant which flows through the heat exchanger tube 8, and a to-be-heat-transfer medium into a counterflow. Further, when the second heat exchanger 4a and the second heat exchanger 4b function as an evaporator, the dew condensation water generated in the second heat exchanger 4a and the second heat exchanger 4b is converted into the first heat exchanger 2a. (Or the first heat exchanger 2b) and the expansion device 3a (or the expansion device 3b) are supplied to any position, or are supplied to predetermined positions of the first heat exchanger 2a and the first heat exchanger 2b. As a result, the heat exchange efficiency of the vehicle air conditioner 100 can be improved.

In addition, description of said vehicle air conditioner 100 demonstrated as what performs a cooling operation (when the 2nd heat exchanger 4a and the 2nd heat exchanger 4b functioned as an evaporator).
However, the vehicle air conditioner 100 can perform the heating operation by causing the second heat exchanger 4a and the second heat exchanger 4b to function as radiators by switching the flow of the refrigerant pipe 7 using a four-way valve. It goes without saying that it will be possible.

  DESCRIPTION OF SYMBOLS 1a Compressor, 1b Compressor, 2a 1st heat exchanger, 2b 1st heat exchanger, 3a expansion device, 3b expansion device, 4a 2nd heat exchanger, 4b 2nd heat exchanger 5 Exhaust fan, 6 Intake fan 7 refrigerant pipe, 8 heat transfer tube, 9 heat radiation member, AA dotted line, AR1 arrow, AR2 arrow, PA1 watering location, PA2 watering location, PA3 dotted line, AX1 arrow, AX2 arrow, FL1 arrow, FL2 arrow.

Claims (1)

In a vehicle air conditioner comprising a compressor, a first heat exchanger, a throttling device, and a second heat exchanger, which are connected annularly via a refrigerant pipe and have a refrigerant circuit constituting a refrigeration cycle,
An exhaust fan provided at a central portion in the vehicle width direction and two sets of the refrigerant circuits,
Using a refrigerant that becomes a supercritical state in the high pressure part of the two sets of refrigerant circuits,
The first heat exchangers of the two sets of refrigerant circuits are:
It is installed in the vehicle width direction via the exhaust fan, and sucks the heat transfer medium from the side of the vehicle.
A plurality of flat plate fins arranged in parallel, and provided through the flat plate fin, in a row direction in which the heat transfer medium flows, and in a direction orthogonal to the row direction. A plurality of heat transfer tubes provided in a certain step direction,
The heat transfer tubes are provided so that the number in the step direction is smaller than the number in the row direction, and the plurality of flat plate fins are provided so as to be orthogonal to the flow direction of the heat transfer medium; and The first heat exchanger is installed such that the flow direction of the heat transfer medium and the refrigerant flowing in the heat transfer pipe are opposed to each other .
When the second heat exchanger is functioning as an evaporator,
Condensed water generated on the surface of the second heat exchanger is
A surface of the refrigerant pipe connecting between the first heat exchanger and the expansion device;
When the length in the vehicle width direction of the first heat exchanger is defined as 1, 0.6 to 0.8 in the direction from the end on the exhaust fan side to the vehicle side surface of the first heat exchanger. A vehicle air conditioner that is supplied to the range .

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