Refrigeration machine for transport and transport machine

Abstract

A refrigeration machine for transport (3), which is a refrigeration machine for transport (3) for cooling a deep-freeze compartment (21) provided in a transport machine (100), comprising: an internal heat exchanger (53) exchanging heat between air inside the deep-freeze compartment (21) and a first refrigerant, a first compressor (51) compressing the first refrigerant and supplying it to the internal heat exchanger (53), an external heat exchanger (63) exchanging heat between outside air and a second refrigerant, a second compressor (61) compressing the second refrigerant and supplying it to the external heat exchanger (63), and an intermediate heat exchanger (7) exchanging heat between the first refrigerant flowing from the first compressor (51) and the second refrigerant flowing from the external heat exchanger (63), wherein the intermediate heat exchanger (7) is arranged in a region containing the centerline (Ax) in the width direction of the transport machine (100).and wherein the first compressor (51) and the second compressor (61) are arranged in the width direction on one side of the intermediate heat exchanger (7) when viewed from the direction of travel of the transport machine (100).

Description

Technical field The present disclosure relates to a refrigeration machine for transport and a transport machine. General state of the art Transport vehicles that carry goods in a refrigerated state, such as refrigerated trucks, are widely used. One such refrigeration device is known as described in WO 2019 / 142 532 A1. WO 2019 / 142 532 A1 describes a refrigeration device that includes a motor, a generator, an inverter, and a compressor. The motor drives the generator, producing electrical power that then operates the compressor. Furthermore, a configuration has recently been used in which the compressor is powered by electrical energy drawn from the truck's drive motor via an AC generator. Since the motor of the refrigeration unit is no longer needed in this case, the degree of freedom in the design of the various components of the refrigeration unit increases. For example, it is conceivable that the heavy compressor is positioned centrally in the lower section, with the other components, including heat exchangers, arranged around it. US Patent 2015 / 0321539A1 describes a refrigeration unit for a transport vehicle with a first heat exchanger located within the refrigerated compartment and an associated refrigeration circuit containing a first refrigerant, and a second refrigeration circuit containing a second refrigerant, in which a second heat exchanger is located that exchanges heat with the outside air. An intermediate heat exchanger is traversed by the first and second refrigerants. Brief description of the invention Object of the invention However, in the case described above of arranging the compressor in the middle, there is a possibility that, due to the proximity to the driver's seat of the tractor unit, the driver's safety may be compromised if coolant leaks from the compressor due to an impact or contact. The purpose of the present disclosure is to solve the problem described above and to provide a transport machine and a refrigeration machine for transport with improved safety. Means of solving the task This problem is solved by a refrigeration machine for transport having the features of claim 1 and a transport machine having the features of claim 4 or 5. Preferred embodiments follow from the remaining claims. To solve the problem described above, the refrigeration machine for transport of the present disclosure is a refrigeration machine for transport for cooling a deep-freeze compartment provided in a transport machine and includes an internal heat exchanger exchanging heat between air inside the deep-freeze compartment and a first refrigerant, a first compressor compressing the first refrigerant and supplying it to the internal heat exchanger, an external heat exchanger exchanging heat between outside air and a second refrigerant, a second compressor compressing the second refrigerant and supplying it to the external heat exchanger, and an intermediate heat exchanger exchanging heat between the first refrigerant flowing from the first compressor and the second refrigerant flowing from the external heat exchanger.wherein the first compressor and the second compressor are arranged on one side in the width direction when viewed from the direction of travel of the transport machine. Effect of the invention The present disclosure makes it possible to provide a refrigeration machine for transport and a transport machine with improved safety. Brief description of the characters Fig. 1 is a side view showing the construction of a transport machine according to a first embodiment of the present disclosure. Fig. 2 is a circuit diagram showing the construction of the transport refrigeration machine according to the first embodiment of the present disclosure. Fig. 3 is a front view of the transport refrigeration machine according to the first embodiment of the present disclosure. Fig. 4 is a front view of a transport refrigeration machine according to a second embodiment of the present disclosure. Fig. 5 is a diagram of the transport machine turning right according to the second embodiment of the present disclosure. Embodiments of the invention First embodiment In the following, with reference to Fig. 1, Fig. 2 to Fig. 3, a refrigeration machine for transport 3 and a transport machine 100 according to a first embodiment of the present disclosure are described. Construction of the transport machine As shown in Fig. 1, the transport machine 100 comprises a tractor unit 1 and a trailer 2. The tractor unit 1 has a cab 1C, an engine 11, and an AC motor 13. The cab 1C serves as the living space for a driver's seat or the like. The engine 11 is a drive unit for supplying tractive power to the tractor unit 1 itself and is located in the lower part of the cab 1C. Specifically, the engine 11 is either a diesel engine or a hybrid engine. An AC machine 13 is connected to the output shaft of motor 11. The AC machine 13 generates electrical power by rotating in sync with the output shaft of motor 11. The electrical power generated by the AC machine 13 is used to drive the refrigeration unit 3 described below and to charge a battery 4. The electrical power of the battery 4 can also be used to drive the refrigeration unit 3. Trailer 2 is a trailer pulled by tractor 1. Trailer 2 has a refrigerated compartment 21, a refrigeration unit 3, and a battery 4. The refrigerated compartment 21 is a space inside trailer 2 that is loaded with cargo requiring refrigeration or deep freezing. The refrigeration unit 3 is installed to regulate the temperature in the refrigerated compartment 21. Assembly of the refrigeration unit for transport Next, the construction of the refrigeration unit for transport 3 will be described with reference to Fig. 2. As shown in Fig. 2, the refrigeration unit for transport 3 has an inner circuit 31, an outer circuit 32 and an intermediate heat exchanger 7. The internal circuit 31 comprises an internal line P1, a first compressor 51, a first expansion valve 52, an internal heat exchanger 53, and an internal fan 54. The internal line P1 includes a first line P11, a second line P12, a third line P13, and a fourth line P14. The first line P11 connects the first compressor 51 and the intermediate heat exchanger 7. The second line P12 connects the intermediate heat exchanger 7 and the first expansion valve 52. The third line P13 connects the first expansion valve 52 and the internal heat exchanger 53. The fourth line P14 connects the internal heat exchanger 53 and the first compressor 51. These internal lines P1 are filled with carbon dioxide as the first refrigerant. The first compressor 51 compresses gaseous low-pressure coolant drawn in from the fourth line P14 and produces gaseous high-pressure, high-temperature coolant. This gaseous high-pressure, high-temperature coolant flows through the first line P11 into the intermediate heat exchanger 7. The intermediate heat exchanger 7 facilitates heat exchange between the second coolant flowing through the external circuit 32 (described later) and the first coolant. This process compresses the gaseous coolant in the intermediate heat exchanger 7, resulting in liquid high-pressure coolant. The liquid high-pressure coolant is routed through the second line P12 to the first expansion valve 52. As it passes through the first expansion valve 52, the liquid high-pressure coolant loses pressure and becomes liquid low-temperature, low-pressure coolant. The liquid refrigerant, having passed through the first expansion valve 52 and becoming a low-temperature, low-pressure refrigerant, flows through the third line P13 into the internal heat exchanger 53. The internal heat exchanger 53 is located inside the freezer compartment 21. Heat exchange takes place in the internal heat exchanger 53 between the air in the freezer compartment 21 and the first refrigerant. The interior fan 54 is provided to direct air from the freezer compartment 21 to the internal heat exchanger 53. As the liquid low-temperature refrigerant absorbs heat in the freezer compartment 21, the temperature in the freezer compartment 21 decreases. In other words, the interior of the freezer compartment 21 is cooled. Simultaneously with the rise in temperature of the liquid refrigerant, the refrigerant transitions from the liquid phase to the gaseous phase and becomes a gaseous, low-pressure refrigerant. The gaseous coolant, which has become low-pressure coolant through the internal heat exchanger 53, is drawn back into the first compressor 51 through the fourth line P14. The external circuit 32 comprises an external line P2, a second compressor 61, a second expansion valve 62, an external heat exchanger 63, and an external fan 64. The external line P2 has a first line P21, a second line P22, a third line P23, and a fourth line P24. The first line P21 connects the second compressor 61 and the external heat exchanger 63. The second line P22 connects the external heat exchanger 63 and the second expansion valve 62. The third line P23 connects the second expansion valve 62 and the intermediate heat exchanger 7. The fourth line P24 connects the intermediate heat exchanger 7 and the second compressor 61. These external lines P2 are filled, for example, with propane as a second refrigerant. The second compressor 61 compresses gaseous low-pressure refrigerant drawn in from the fourth line P24 and produces gaseous high-pressure, high-temperature refrigerant. This gaseous high-pressure, high-temperature refrigerant flows through the first line P21 into the external heat exchanger 63. The external heat exchanger 63 is located outside the deep-freeze room 21 described above. The external heat exchanger 63 facilitates heat exchange between the outside air and the second refrigerant. The external fan 64 is provided to direct outside air to the external heat exchanger 63. This causes the gaseous refrigerant to be compressed in the external heat exchanger 63, resulting in liquid high-pressure refrigerant. The liquid low-temperature, high-pressure coolant is routed through the second line P22 to the second expansion valve 62. As it passes through the second expansion valve 62, the liquid high-pressure coolant loses pressure and becomes liquid low-temperature, low-pressure coolant. The liquid coolant, which has become low-temperature, low-pressure coolant by passing through the second expansion valve 62, flows through the third line P23 into the intermediate heat exchanger 7. The intermediate heat exchanger 7 facilitates heat exchange between the first coolant flowing through the inner circuit 31 described above and the second coolant. Specifically, heat exchange takes place between the gaseous high-temperature, high-pressure coolant (the first coolant) flowing through the first line P11 of the inner circuit 31 and the liquid low-temperature, low-pressure coolant (the second coolant) flowing through the third line P23 of the outer circuit 32. As a result, the liquid coolant flowing through the third line 23 in the outer circuit 32 transitions into the gaseous phase and becomes gaseous low-pressure coolant. The gaseous refrigerant, which has been converted to low-pressure refrigerant by the intermediate heat exchanger 7, is drawn back into the second compressor 61 via the fourth line P24. By continuously performing such a cycle, the temperature of the freezer compartment 21 is regulated to a desired value. Arrangement of the refrigeration unit for transport The arrangement of the respective components of the refrigeration unit 3 described above is further described with reference to Fig. 3. Fig. 3 is a front view of the trailer 2. As shown in Fig. 3, the refrigeration unit 3 is arranged on a front surface 2A of the trailer 2. The intermediate heat exchanger 7 is located in the center at the bottom of the front surface 2A. More specifically, the intermediate heat exchanger 7 is positioned in an area containing the center line Ax of the front surface 2A. The first compressor 51 and the second compressor 61 are arranged on one side of the intermediate heat exchanger 7. In other words, when the transport vehicle 100 is used on a right-hand traffic road, the first compressor 51 and the second compressor 61 are arranged on the passenger side (the right side in the direction of travel).Thus, the first compressor 51 and the second compressor 61 are arranged on one side of the width direction. On the opposite side of the intermediate heat exchanger 7, an automotive electrical box 8 is arranged. The automotive electrical box 8 houses devices (for example, an inverter and the like) for driving the first compressor 51 and the second compressor 61. Thus, when the transport machine 100 is viewed from the direction of travel, the first compressor 51, the second compressor 61, and the automotive electrical box 8 are arranged axially symmetrically with the intermediate heat exchanger 7 (the center line Ax) as the axis of symmetry. Preferably, rotary compressors or scroll compressors are used as the first compressor 51 and the second compressor 61 and are distributed such that their dimensions, size, and weight are equivalent to the overall dimensions of the automotive electrical box 8. Several external fans 64 are positioned above the intermediate heat exchanger 7. The external fans 64 are arranged along the centerline Ax described above. The example in Fig. 3 shows an example in which two external fans 64 are arranged vertically. The number of external fans 64 is not limited to two, but can also be one, three, or more. Furthermore, the internal heat exchanger 53 and the interior fan 54 are arranged behind the external fans 64, although this is not shown. On one side of the width of the external fans 64, the external heat exchanger 63 is provided. Furthermore, on the other side of the width of the external fans 64, pipes are arranged, which are not shown. These pipes house the first expansion valve 52, the second expansion valve 62, and at least part of the internal pipes P1 and external pipes P2. Mode of action, effect The above-described design reduces the probability that the safety of the driver's seat or the passenger's seat will be endangered in the event of a coolant leak, compared, for example, to the case where the first compressor 51 and the second compressor 61 are arranged centrally in the width direction. Furthermore, the above-described design allows the heavy loads – first compressor 51, second compressor 61, and intermediate heat exchanger 7 – to be positioned below the external fans 64. This reduces the effort required to lift heavy loads during installation and maintenance of these devices, and further increases safety and maintainability. In addition, the above-described design, since the first compressor 51 and the second compressor 61 are provided on the side opposite the driver's seat, minimizes the likelihood of an impact on the driver's seat even in the event of a coolant leakage due to an impact or contact with the first compressor 51 or the second compressor 61. This concludes the description of the first embodiment of the present disclosure. It is possible to modify or redesign the above-described setup in various ways, provided that the essential content of the present disclosure is not altered. For example, in the embodiment described above, using the example of a road with right-hand traffic, a setup was described in which the first compressor 51 and the second compressor 61 are located on the right-hand side in the direction of travel. However, if the transport machine 100 is adapted for roads with left-hand traffic, a setup is preferred in which the first compressor 51 and the second compressor 61 are located on the left-hand side (on the passenger side) in the direction of travel. Second embodiment The second embodiment of the present disclosure will now be described with reference to Figures 4 and 5. The same reference numerals are used for the same setup as in the first embodiment described above, and a detailed description is omitted. As shown in Figure 4, the arrangement of the first compressor 51 and the second compressor 61 differs from that of the first embodiment in the present embodiment. In the present embodiment, the first compressor 51 and the second compressor 61 are positioned on the opposite side of the width direction of the intermediate heat exchanger 7. In other words, when the transport machine 100 is used on a right-hand traffic road, the first compressor 51 and the second compressor 61 are arranged on the driver's side (the left side in the direction of travel).Thus, the first compressor 51 and the second compressor 61 are arranged on one side opposite the width. The automotive electrical box 8, in turn, is arranged on the first side of the width of the intermediate heat exchanger 7. When turning at a left-hand traffic intersection, for example, the front left part of the trailer 2, as shown in Fig. 5, is exposed towards the opposite lane (the side of an oncoming vehicle 90) because the trailer 2 rotates forward relative to the tractor unit 1. Now, let us assume that, in contrast to the setup described above, the first compressor 51 and the second compressor 61 are arranged on the left side opposite the driver's seat D, in the direction of travel. In this case, if a flammable substance such as propane is used as the second refrigerant, there is a risk that safety will be compromised, since the second compressor 61 is exposed towards the oncoming lane.On the other hand, since the first compressor 51 and the second compressor 61 are arranged on the right-hand side in the direction of travel (the side of the driver's seat D) due to the design described above, neither the first compressor 51 nor the second compressor 61 is exposed to the oncoming lane, even when turning right. This increases the safety of the transport machine 100. This concludes the description of the second embodiment of the present disclosure. It is possible to modify or redesign the above-described setup in various ways, provided that the essential content of the present disclosure is not altered. For example, in the second embodiment described above, using the example of a right-hand traffic road, a setup was described in which the first compressor 51 and the second compressor 61 are located on the left side in the direction of travel. However, if the transport machine 100 is adapted for left-hand traffic roads, a setup is preferred in which the first compressor 51 and the second compressor 61 are located on the right side in the direction of travel (on the driver's side). Attachment The contents of the above embodiments of the refrigeration machine for transport 3 and the transport machine 100 can be summarized, for example, as follows. (1) A transport refrigeration machine 3 according to a first embodiment is a transport refrigeration machine 3 for cooling a deep-freeze compartment 21 provided in a transport machine 100 and includes an internal heat exchanger 53 exchanging heat between air inside the deep-freeze compartment 21 and a first refrigerant, a first compressor 51 compressing the first refrigerant and supplying it to the internal heat exchanger 53, an external heat exchanger 63 exchanging heat between outside air and a second refrigerant, a second compressor 61 compressing the second refrigerant and supplying it to the external heat exchanger 63, and an intermediate heat exchanger 7 exchanging heat between the first refrigerant flowing from the first compressor 51 and the second refrigerant flowing from the external heat exchanger 63.wherein the first compressor 51 and the second compressor 61 are arranged on one side in the width direction when viewed from the direction of travel of the transport machine 100. The above-described design reduces the probability that the safety of the driver's seat or the passenger's seat will be endangered in the event of a coolant leak, compared, for example, to the case where the first compressor 51 and the second compressor 61 are arranged centrally in the width direction. (2) A transport refrigeration machine 3 according to a second embodiment additionally includes an external fan 64 supplying air to the internal heat exchanger 53, wherein the first compressor 51, the second compressor 61 and the intermediate heat exchanger 7 are arranged under the external fan 64. The above-described design allows the heavy loads – first compressor 51, second compressor 61, and intermediate heat exchanger 7 – to be positioned below the external fan 64. This reduces the effort required to lift heavy loads during installation and maintenance of these devices, further increasing safety and maintainability. (3) A transport machine 100 according to a third embodiment comprises a tractor unit 1 having a driver's seat arranged on one side in the width direction, a refrigeration unit for transport 3 and a trailer 2 having the aforementioned deep-freeze compartment 21, wherein the first compressor 51 and the second compressor 61 are arranged on the side opposite the driver's seat in the width direction. Due to the above-described design, since the first compressor 51 and the second compressor 61 are provided on the side opposite the driver's seat, even in the event of a coolant leakage due to an impact or contact with the first compressor 51 or the second compressor 61, the probability of an impact on the driver's seat can be minimized. (4) A transport machine 100 according to a fourth embodiment comprises a tractor unit 1 having a driver's seat arranged on one side in the width direction, a refrigeration machine for transport 3 and a trailer 2 having the deep-freeze compartment 21, wherein the second compressor 61 is arranged in the width direction on the side of the driver's seat D. When turning at an intersection with left-hand traffic, for example, the front left part of trailer 2 is exposed towards the oncoming lane because trailer 2 is rotated relative to the tractor unit 1 as it moves forward. Now, let us assume that, in contrast to the setup described above, the first compressor 51 and the second compressor 61 are located on the left side opposite the driver's seat D, in the direction of travel. In this case, if a flammable substance such as propane is used as the second refrigerant, there is a risk that safety will be compromised because the second compressor 61 is exposed towards the oncoming lane.On the other hand, since the first compressor 51 and the second compressor 61 are arranged on the right-hand side in the direction of travel (the side of the driver's seat D) due to the design described above, neither the first compressor 51 nor the second compressor 61 is exposed to the oncoming lane, even when turning right. This increases the safety of the transport machine 100. Description of the reference symbols 100 Transport vehicle 1 Tractor unit 1C Cab 2 Trailer 2A Front surface 3 Transport refrigeration unit 4 Battery 7 Intermediate heat exchanger 8 Vehicle electrical box 9 Wiring box 11 Engine 13 AC generator 21 Freezer compartment 31 Internal circuit 32 External circuit 51 First compressor 52 First expansion valve 53 Internal heat exchanger 54 Interior fan 61 Second compressor 62 Second expansion valve 63 External heat exchanger 64 External fan 90 Oncoming vehicle D Driver's seat P1 Internal line P2 External line P11, P21 First line P12, P22 Second line P13, P23 Third line P14, P24 Fourth line Ax Center line

Claims

A refrigeration machine for transport (3), which is a refrigeration machine for transport (3) for cooling a deep-freeze compartment (21) provided in a transport machine (100), comprising: an internal heat exchanger (53) exchanging heat between air inside the deep-freeze compartment (21) and a first refrigerant, a first compressor (51) compressing the first refrigerant and supplying it to the internal heat exchanger (53), an external heat exchanger (63) exchanging heat between outside air and a second refrigerant, a second compressor (61) compressing the second refrigerant and supplying it to the external heat exchanger (63), and an intermediate heat exchanger (7) exchanging heat between the first refrigerant flowing from the first compressor (51) and the second refrigerant flowing from the external heat exchanger (63), wherein the intermediate heat exchanger (7) is arranged in a region containing the centerline (Ax) in the width direction of the transport machine (100).and wherein the first compressor (51) and the second compressor (61) are arranged in the width direction on one side of the intermediate heat exchanger (7) when viewed from the direction of travel of the transport machine (100). Refrigeration machine for transport (3) according to claim 1, further comprising an external fan (64) supplying air to the external heat exchanger (63), wherein the first compressor (51), the second compressor (61) and the intermediate heat exchanger (7) are arranged below the external fan (64). Refrigeration machine for transport (3) according to claim 1 or 2, further comprising: a box (8) for electrical components in which electrical devices for driving the first compressor (51) and the second compressor (61) are housed, wherein the box (8) for electrical components is arranged on the other side in relation to the intermediate heat exchanger (7) in the width direction of the transport machine (100). Transport machine (100), comprising: a tractor unit (1) having a driver's seat (D) arranged on one side in the width direction, a refrigeration machine for transport (3) according to one of claims 1 to 3 and a trailer (2) having the deep-freeze compartment (21), wherein the first compressor (51) and the second compressor (61) are arranged on the side opposite the driver's seat (D) in the width direction. Transport machine (100), comprising: a tractor unit (1) having a driver's seat (D) arranged on one side of the width direction, a refrigeration machine for transport (3) according to one of claims 1 to 3 and a trailer (2) having the deep-freeze compartment (21), wherein the first compressor (51) and the second compressor (61) are arranged in the width direction on the side of the driver's seat (D).

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