Patent Application
20240149925
The present disclosure relates to an air conditioner for a railway vehicle.
A passenger compartment of a railway vehicle is air-conditioned with a refrigeration cycle, similarly to a passenger compartment of an automobile. Although a passenger compartment of an automobile can be air-conditioned with a single refrigeration cycle system, a passenger compartment of a railway vehicle that is much larger than a passenger compartment of an automobile uses at least two refrigeration cycle systems for air conditioning. A passenger compartment of a railway vehicle is thus air-conditioned with an air conditioner for a railway vehicle including at least a pair of heat exchangers.
Patent Literature 1 describes a layout of a pair of heat exchangers in an air conditioner for a railway vehicle. As described in Patent Literature 1, the pair of heat exchangers face each other across a blower. The blower generates airflow passing through each heat exchanger in the thickness direction of the heat exchanger.
Each heat exchanger in Patent Literature 1 includes multiple refrigerant pipes inside at different positions in the thickness direction of the heat exchanger. The refrigerant pipes are serially connected. In each heat exchanger in Patent Literature 1, the refrigerant thus sequentially passes through the refrigerant pipes that are at different positions in the thickness direction. More specifically, the refrigerant passes through the refrigerant pipes from one end to the other end in the thickness direction.
Each heat exchanger in Patent Literature 1 is thus placed to have either the refrigerant passing through the refrigerant pipes in the direction opposite to the airflow passing through the heat exchanger (hereafter referred to as being in an opposite placement) or the refrigerant passing through the refrigerant pipes in the direction parallel to the airflow passing through the heat exchanger (hereafter referred to as being in a parallel placement).
The opposite placement yields higher heat-exchange efficiency than the parallel placement. Although the pair of heat exchangers may both be in the opposite placement, the heat exchangers in the opposite placement are mirror symmetric across a blower and cannot have the same structure. In other words, the pair of heat exchangers have different specifications.
When the pair of heat exchangers across the blower have the same specifications, one of the heat exchangers is in the opposite placement and the other in the parallel placement. The other heat exchanger may thus have lower heat-exchange efficiency.
Although the pair of heat exchangers in Patent Literature 1 are to be in the opposite placement and have different specifications to avoid lower heat-exchange efficiency as described above, such two heat exchangers with different specifications can increase the costs of air conditioners for railway vehicles and increase difficulty in manufacturing the air conditioners. The above issues, uncommon to the air conditioner for an automobile that includes a single refrigeration cycle, occur to the air conditioner for a railway vehicle that includes a pair of heat exchangers facing each other.
An objective of the present disclosure is to provide an air conditioner for a railway vehicle that is easily manufactured at low costs.
An air conditioner for a railway vehicle according to an aspect of the present disclosure includes a first heat exchanger and a second heat exchanger facing each other, and a blower located between the first heat exchanger and the second heat exchanger and configured to generate airflow passing through the first heat exchanger and the second heat exchanger. Each of the first heat exchanger and the second heat exchanger includes a body including a stacked structure in which refrigerant pipes and fins are alternately stacked in a direction perpendicular to a thickness direction in which the airflow passes through the first heat exchanger or the second heat exchanger. Each of the refrigerant pipes internally defines a plurality of refrigerant flow paths. The plurality of refrigerant flow paths in each of the refrigerant pipes are arranged in the thickness direction. Each of the first heat exchanger and the second heat exchanger includes a first header pipe located at a first end of the body in a length direction of the refrigerant pipes. The first header pipe connects the plurality of refrigerant flow paths in each of the refrigerant pipes to one another at the first end. Each of the first heat exchanger and the second heat exchanger includes a second header pipe located at a second end of the body in the length direction of the refrigerant pipes. The second header pipe connects the plurality of refrigerant flow paths in each of the refrigerant pipes to one another at the second end.
In the above structure, each of the first heat exchanger and the second heat exchanger includes the refrigerant pipes each defining the plurality of refrigerant flow paths that are connected to one another at both ends in the length direction of the refrigerant pipes. In other words, the refrigerant flow paths in each refrigerant pipe arranged in the thickness direction are connected in parallel. The refrigerant thus passes through the plurality of refrigerant flow paths in parallel, instead of passing through the paths in sequence.
The first heat exchanger is less likely to have a change in the heat-exchange efficiency between when placed to allow airflow from a first end to a second end in the thickness direction of the first heat exchanger and when placed to allow airflow from the second end to the first end in the thickness direction of the first heat exchanger. Similarly, the second heat exchanger is less likely to have a change in the heat-exchange efficiency between when placed to allow airflow from a first end to a second end in the thickness direction of the second heat exchanger and when placed to allow airflow from the second end to the first end in the thickness direction of the second heat exchanger.
The first heat exchanger and the second heat exchanger having the same specifications can avoid lower heat-exchange efficiency of one of the first heat exchanger or the second heat exchanger that results from the directions of the airflow passing through the first heat exchanger and the second heat exchanger. The air conditioner for a railway vehicle including the first heat exchanger and the second heat exchanger having the same specifications can be easily manufactured at low costs.
An air conditioner for a railway vehicle according to an embodiment is described below with reference to the drawings. In the drawings, the same reference signs denote the same or corresponding components.
As illustrated in
The air-conditioning device 100 provides two refrigeration cycles. More specifically, the air-conditioning device 100 includes a refrigeration cycle system 110 that provides a first refrigeration cycle and a refrigeration cycle system 120 that provides a second refrigeration cycle.
The refrigeration cycle system 110 includes a first outdoor heat exchanger 111 serving as a condenser that condenses the refrigerant and a first cooperative device that provides the first refrigeration cycle in cooperation with the first outdoor heat exchanger 111. The first cooperative device includes a first expander 112 that expands the refrigerant condensed by the first outdoor heat exchanger 111, a first indoor heat exchanger 113 serving as an evaporator that evaporates the expanded refrigerant, and a first compressor 114 that compresses the evaporated refrigerant to return the refrigerant to the first outdoor heat exchanger 111.
The refrigeration cycle system 110 also includes a first connection pipe 115 through which the refrigerant flows. The first connection pipe 115 connects the first outdoor heat exchanger 111, the first expander 112, the first indoor heat exchanger 113, and the first compressor 114 to form a closed circuit.
Similarly, the refrigeration cycle system 120 includes a second outdoor heat exchanger 121 serving as a condenser that condenses the refrigerant and a second cooperative device that provides the second refrigeration cycle in cooperation with the second outdoor heat exchanger 121. The second cooperative device includes a second expander 122 that expands the refrigerant condensed by the second outdoor heat exchanger 121, a second indoor heat exchanger 123 serving as an evaporator that evaporates the expanded refrigerant, and a second compressor 124 that compresses the evaporated refrigerant to return the refrigerant to the second outdoor heat exchanger 121.
The refrigeration cycle system 120 also includes a second connection pipe 125 through which the refrigerant flows. The second connection pipe 125 connects the second outdoor heat exchanger 121, the second expander 122, the second indoor heat exchanger 123, and the second compressor 124 to form a closed circuit.
The air-conditioning device 100 also includes an outdoor blower 130. The outdoor blower 130 promotes heat exchange between the first outdoor heat exchanger 111 and air outside the vehicle or outside air and heat exchange between the second outdoor heat exchanger 121 and outside air. The air-conditioning device 100 also includes an indoor blower 140. The indoor blower 140 promotes heat exchange between the first indoor heat exchanger 113 and air in the passenger compartment and heat exchange between the second indoor heat exchanger 123 and air in the passenger compartment.
The housing 200 includes a box-shaped base frame 220 having a bottom plate 210 and atop plate 230 covering an upper opening of the base frame 220. In FIG. 1, a part of the top plate 230 is illustrated to indicate the inside of the housing 200.
For ease of explanation, a right-handed XYZ orthogonal coordinate system is defined with X-axis parallel to the length direction of the railway vehicle, Y-axis parallel to the width direction of the railway vehicle, and Z-axis parallel to the height direction of the railway vehicle. A positive Z-direction corresponds to the upward direction in the height direction.
The housing 200 also includes partition walls 240 and 250 that partition the interior space defined by the base frame 220 and the top plate 230 into an outdoor-unit chamber S1 serving as a first compartment, an indoor-unit chamber S2 serving as a second compartment, and a compressor chamber S3. The outdoor-unit chamber S1, the indoor-unit chamber S2, and the compressor chamber S3 are arranged in X-direction.
The outdoor-unit chamber S1 accommodates the first outdoor heat exchanger 111, the second outdoor heat exchanger 121, and the outdoor blower 130. The indoor-unit chamber S2 accommodates the first expander 112, the first indoor heat exchanger 113, the second expander 122, the second indoor heat exchanger 123, and the indoor blower 140. The compressor chamber S3 accommodates the first compressor 114 and the second compressor 124.
The air conditioner 400 for a railway vehicle according to the present embodiment is characterized in that the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 in the outdoor-unit chamber S1 have the same structure. The structure of the outdoor-unit chamber S1 is described in detail below.
The outdoor blower 130 is located between the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121. The outdoor blower 130 is an example of a blower located between the first heat exchanger and the second heat exchanger.
More specifically, the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 are symmetric to each other with respect to an imaginary XZ plane VP extending through the position of the outdoor blower 130. The imaginary XZ plane VP is an imaginary plane parallel to X-axis and Z-axis.
An angle θ between the first outdoor heat exchanger 111 and the bottom plate 210 is equal to an angle θ between the second outdoor heat exchanger 121 and the bottom plate 210. In the present embodiment, the angle θ is greater than or equal to 20 degrees and less than or equal to 70 degrees.
The housing 200 has first vents 261 connected outside in a portion facing the first outdoor heat exchanger 111. The housing 200 has second vents 262 connected outside in a portion facing the second outdoor heat exchanger 121. The housing 200 has third vents 263 connected outside in a portion facing the outdoor blower 130.
The outdoor blower 130 draws outside air into the outdoor-unit chamber S1 through the first vents 261 and the second vents 262 or through the third vents 263, allows the outside air drawn into the outdoor-unit chamber S1 to pass through the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121, and discharges the air outside through the third vents 263 or through the first vents 261 and the second vents 262.
More specifically, the outdoor blower 130 draws outside air into the outdoor-unit chamber S1 through the third vents 263 to generate airflow AF in the outdoor-unit chamber S1. The airflow AF passes through each of the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 in the thickness direction and then flows out through the first vents 261 and the second vents 262.
A comparative example as an example known technique is described below for the issues to be solved with the structure according to the present embodiment.
The first outdoor heat exchanger 900 includes an inlet 930 through which the refrigerant to be used for heat exchange by the first outdoor heat exchanger 900 flows in, and an outlet 940 through which the refrigerant used for heat exchange by the first outdoor heat exchanger 900 flows out. The inlet 930 and the outlet 940 are at different positions in the thickness direction.
The multiple refrigerant pipes 911 to 914 are serially interconnected at turns (not illustrated) located at both ends in X-direction. The refrigerant thus sequentially passes through the refrigerant pipes 911 to 914 at different positions in the thickness direction. More specifically, the refrigerant sequentially passes through the refrigerant pipes 911, 912, 913, and 914 in this order. Arrow AL indicates the direction in which the refrigerant passes through the refrigerant pipes.
The first outdoor heat exchanger 900 is in an opposite placement that allows the direction indicated by arrow AL to be opposite to the direction of the airflow AF passing through the first outdoor heat exchanger 900. Similarly, a second outdoor heat exchanger (not illustrated) in the comparative example facing the first outdoor heat exchanger 900 is to be in the opposite placement. The opposite placement can yield higher heat-exchange efficiency than a parallel placement that allows the direction indicated by arrow AL to be parallel to the direction of the airflow AF.
When the first outdoor heat exchanger 900 and the second outdoor heat exchanger (not illustrated) are both in the opposite placement, the first outdoor heat exchanger 900 and the second outdoor heat exchanger (not illustrated) are to be mirror symmetric to each other. In other words, the first outdoor heat exchanger 900 and the second outdoor heat exchanger (not illustrated) cannot be congruent.
More specifically, with known techniques, the first outdoor heat exchanger 900 and the second outdoor heat exchanger (not illustrated) have different specifications to have both the heat exchangers in the opposite placement. Such two outdoor heat exchangers with different specifications increase the costs of air conditioners 400 for railway vehicles and increase difficulty in manufacturing the air conditioners 400.
The first outdoor heat exchanger 900 and the second outdoor heat exchanger (not illustrated) may have the same specifications when one the first outdoor heat exchanger 900 or the second outdoor heat exchanger is in the opposite placement and the other in the parallel placement. However, the first outdoor heat exchanger 900 or the second outdoor heat exchanger (not illustrated) in the parallel placement may have lower heat-exchange efficiency.
The present embodiment is directed to the issues of avoiding lower heat-exchange efficiency that results from the directions of airflow AF and allowing the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 to have the same specifications.
The present embodiment directed to the above issues is described below. The first outdoor heat exchanger 111 is described below. The second outdoor heat exchanger 121 has the same structure as the first outdoor heat exchanger 111.
In the body 330, the refrigerant pipes 310 and the fins 320 are stacked in the direction (hereafter referred to as a stacking direction) perpendicular to a length direction (hereafter referred to as a refrigerant pipe length direction) of the refrigerant pipes 310 and to the thickness direction in which the airflow AF illustrated in
Each refrigerant pipe 310 internally defines multiple refrigerant flow paths 311. The refrigerant flows through the refrigerant flow paths 311. The refrigerant flow paths 311 in the refrigerant pipes 310 are arranged in the thickness direction perpendicular to the page of
Each fin 320 is brazed to adjacent ones of the refrigerant pipes 310 in the stacking direction. Each fin 320 is thus thermally connected to the adjacent refrigerant pipes 310 in the stacking direction. More specifically, each fin 320 is a corrugated fin being a metal plate folded in a wave shape.
The first outdoor heat exchanger 111 includes a first header pipe 340 located at one end of the body 330 in the refrigerant pipe length direction and a second header pipe 350 located at the other end of the body 330 in the refrigerant pipe length direction. The first header pipe 340 and the second header pipe 350 extend in the stacking direction.
The first header pipe 340 connects the refrigerant flow paths 311 in each refrigerant pipe 310 to one another at one end in the refrigerant pipe length direction. The second header pipe 350 connects the refrigerant flow paths 311 in each refrigerant pipe 310 to one another at the other end in the refrigerant pipe length direction. The refrigerant flow paths 311 arranged in the thickness direction in each refrigerant pipe 310 are thus connected in parallel to one another.
The first header pipe 340 includes an inlet 360 through which the refrigerant to be used by the first outdoor heat exchanger 111 for heat exchange flows in, and an outlet 370 through which the refrigerant used by the first outdoor heat exchanger 111 for heat exchange flows out.
The inlet 360 and the outlet 370 face each other in the stacking direction. The first connection pipe 115 illustrated also in
The first header pipe 340 includes a partition 341 that blocks the refrigerant between the inlet 360 and the outlet 370 in the stacking direction. The direction from the partition 341 toward the inlet 360 in the stacking direction is defined as a positive stacking direction, and the direction from the partition 341 toward the outlet 370 in the stacking direction is defined as a negative stacking direction.
The refrigerant flows from the first header pipe 340 toward the second header pipe 350 through the refrigerant flow paths 311 in the refrigerant pipes 310 located in the positive stacking direction from the partition 341. The refrigerant flows from the second header pipe 350 toward the first header pipe 340 through the refrigerant flow paths 311 in the refrigerant pipes 310 located in the negative stacking direction from the partition 341.
The first outdoor heat exchanger 111 thus has heat exchange efficiency that is less dependent on the direction of the airflow AF passing through the first outdoor heat exchanger 111 in the thickness direction. The second outdoor heat exchanger 121 and the first outdoor heat exchanger 111 having the same specifications can thus avoid lower heat-exchange efficiency of one of the first outdoor heat exchanger 111 or the second outdoor heat exchanger 121 that results from the directions of the airflow AF passing through the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121.
The above structure is described more specifically with reference to
As described above, the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 each include the refrigerant flow paths 311 illustrated in
The first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 having the same specifications herein refer to the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 having the overall shapes of the flow paths for the refrigerant being congruent. The shapes being congruent refers to the shapes being superposable on each other imaginarily. The first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 can thus have some structural differences other than in the overall shape of the flow paths for the refrigerant.
As described above, the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 can have the same specifications. Thus, the air conditioner 400 for a railway vehicle can be easily manufactured at low costs.
The relative positions of the first outdoor heat exchanger 111 and the second outdoor heat exchanger 121 are described in detail below.
As illustrated in
The first header pipe 340 of the first outdoor heat exchanger 111 is located at an end of the first outdoor heat exchanger 111 nearer the indoor-unit chamber S2 in X-direction. Similarly, the first header pipe 340 of the second outdoor heat exchanger 121 is located at an end of the second outdoor heat exchanger 121 nearer the indoor-unit chamber S2 in X-direction. More specifically, the first header pipe 340 of the first heat exchanger 111 and the first outdoor header pipe 340 of the second outdoor heat exchanger 121 face the partition wall 240 partitioning the outdoor-unit chamber S1 and the indoor-unit chamber S2 from each other.
The first header pipe 340 that allows the refrigerant to flow into and out of the first outdoor heat exchanger 111 is located at the end in X-direction nearer the indoor-unit chamber S2. This structure reduces the path length of the first connection pipe 115 in the refrigeration cycle system 110.
The first header pipe 340 that allows the refrigerant to flow into and out of the second outdoor heat exchanger 121 is located at the end in X-direction nearer the indoor-unit chamber S2. This structure reduces the path length of the second connection pipe 125 in the refrigeration cycle system 120.
The first connection pipe 115 and the second connection pipe 125 illustrated in
The embodiment described above may be modified as described below.
Modification 1
As illustrated in
In other words, the directions of the airflow AF in
Thus, the structure for generating the airflow AF in
Modification 2
As illustrated in
Modifications 3 and 4
Modification 5
As illustrated in
The indoor blower 140 is located between the first indoor heat exchanger 113 and the second indoor heat exchanger 123. The indoor blower 140 generates airflow passing through the first indoor heat exchanger 113 and the second indoor heat exchanger 123 in the thickness direction in the indoor-unit chamber S2.
The structures illustrated in
The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to betaken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/018163 | 5/13/2021 | WO |
