AIR CONDITIONING ARRANGEMENT FOR THE INTERIOR OF A VEHICLE

Description

[0001] The invention relates to an air conditioning arrangement for an interior of a vehicle according to the preamble of claim 1. Thereafter, the air conditioning arrangement comprises an air conditioning device for providing conditioned room air and a cooling unit arranged in the interior, which has a refrigeration circuit which has a heat exchanger for cooling a refrigerant of the refrigeration circuit, which heat exchanger is supplied with the room air.

[0002] For example, air conditioning arrangements of the type mentioned at the outset are known from DE 198 47 504 C1, which relates to a method for controlling the air volume flows in an air-conditioning system, DE 10 2019 210 084 A1, which relates to a vehicle with a ventilation device and a cooling box device, and DE 10 2012 108 886 A1, which discloses a heat exchanger arrangement and an air-conditioning system of a motor vehicle.

[0003] Such an air conditioning system is found, for example, in the interiors of vehicles, particularly rail vehicles. For example, the interior of an on-board galley is air-conditioned by an air conditioning unit, which maintains key air parameters, such as temperature and humidity, according to specified values. Such on-board galleys also contain cooling units, which serve to provide cooling capacity, for example, in refrigerators, freezers, refrigerated display cases, etc.

[0004] The cooling of the cooling unit's refrigerant takes place at the heat exchanger / condenser of the cooling unit, using the air present in the interior.

[0005] The task of such an air conditioning arrangement is to dissipate the waste heat from a cooling unit as efficiently as possible.

[0006] This object is achieved by an air conditioning arrangement according to claim 1.

[0007] According to this, the air conditioning arrangement described at the outset is characterized in that the heat exchanger is spatially divided into a hot gas section and a low-temperature section, the room air sucked in to cool the heat exchanger is divided into an exhaust air portion and a recirculated air portion, wherein the low-temperature section of the heat exchanger is supplied with the recirculated air portion of the room air and the hot gas section of the heat exchanger is supplied with the exhaust air portion of the room air.

[0008] By supplying the hot-gas section with the exhaust air portion and the low-temperature section with the recirculated air portion, the recirculated air portion returned to the vehicle interior has a comparatively low temperature, allowing the air conditioning unit that supplies the room air to the vehicle interior to operate at a lower (cooling) output. In contrast, the hot-gas section of the heat exchanger is supplied with the exhaust air portion that is discharged from the vehicle after passing through the hot-gas section.

[0009] In particular, it is also possible for the low-temperature section to be supplied not only with the air that will later be conveyed as recirculated air to the air conditioning unit, but with a total air flow that is only divided into a recirculated air portion and an exhaust air portion that will be conveyed further to the hot gas section after passing through the low-temperature section.

[0010] In principle, all types of heat exchangers can be used as heat exchangers for the cooling unit. However, it is preferred that the heat exchanger or condenser of the refrigeration circuit be designed as a cross-counterflow heat exchanger, as this design is particularly efficient under the given conditions in a vehicle.

[0011] The hot gas section and the low-temperature section of the heat exchanger can be directly adjacent to each other. Alternatively, it is possible to spatially separate the hot gas section and the low-temperature section of the heat exchanger.

[0012] In a further development of the invention, a fan is assigned to the hot-gas section for drawing in the exhaust air portion from the room air, and a fan is assigned to the low-temperature section for drawing in the recirculated air portion from the room air. In this embodiment, the intake of cooling air (later recirculated air or exhaust air) takes place separately. The exhaust air portion is fed directly to the hot-gas section, and the recirculated air portion of the room air is fed directly to the low-temperature section.

[0013] Alternatively, it is possible to provide an air distribution device arranged between the hot-gas section and the low-temperature section, which divides the drawn-in room air into the exhaust air portion and the recirculated air portion. In this embodiment, all of the room air, drawn in, for example, by a fan, passes through the low-temperature section of the refrigeration unit. On an outlet side of the low-temperature section, the air distribution device extracts a portion of the recirculated air from the air flow present there and redirects it back into the interior of the vehicle. A remaining portion of the drawn-in room air is guided further to the hot-gas section of the heat exchanger and cools the coolant of the refrigeration circuit of the refrigeration unit in the hot-gas section.

[0014] Preferably, the volume flow of the exhaust air portion is smaller than the volume flow of the recirculated air portion. Since the exhaust air portion leaves the heat exchanger at a significantly higher temperature than the recirculated air portion, it is generally advantageous if the recirculated air portion is larger than the exhaust air portion. However, it is important to ensure that the required final temperature of the coolant, which must be present when leaving the heat exchanger, is also reached. Depending on the application, there are therefore boundary conditions that must be met for a minimum proportion of the room air that must be discharged as exhaust air.

[0015] Preferably, the volume flow of the exhaust air portion is less than 40% of the volume flow of the intake room air.

[0016] The cooling unit can be designed in particular as a gas cooler in which the hot gas section and the low-temperature section are each spatially separated from one another and are generally rectangular, possibly with the same width dimensions.

[0017] Embodiments of the invention are explained in more detail below with reference to the drawings, in which like components are designated by the same reference numerals. In the drawings: Figure 1 shows a schematic representation of an air conditioning arrangement for a vehicle interior in a first embodiment, Figure 2 shows a schematic representation of a fluidic connection of the air conditioning arrangement of Figure 1 , Figure 3 a schematic, graphical representation of temperature profiles of a hot gas section of the air conditioning arrangement of Figure 1, Figure 4 a schematic graphic representation of temperature profiles of a low-temperature section of the air conditioning arrangement of Figure 1 , Figure 5 a schematic representation of an air conditioning arrangement for a vehicle interior in a second embodiment, Figure 6 a schematic representation of a fluidic connection of the air conditioning arrangement of Figure 5 , Figure 7 a schematic, graphical representation of temperature profiles of a hot gas section of the air conditioning arrangement of Figure 5 and Figure 8 a schematic graphic representation of temperature profiles of a low-temperature section of the air conditioning arrangement of Figure 5 .

[0018] The Figures 1 to 4illustrate a first embodiment of an air conditioning system for an on-board galley as an example for the interior of a vehicle, in particular a rail vehicle. An air conditioning unit 1 provides conditioned room air 2 for the interior of the vehicle. A refrigeration unit, in the present embodiment a gas cooler 3, is arranged in the interior of the vehicle. This unit is used to provide cooling capacity for, for example, refrigerators, freezers, and refrigerated display cases. The gas cooler 3 is operated with a refrigerant that is guided in a refrigeration circuit 4. Figure 1 For reasons of clarity, only one condenser of this refrigeration circuit 4, designed as a heat exchanger, is shown, which is used to cool the refrigerant.

[0019] The condenser is spatially divided into a hot-gas section 5 and a low-temperature section 6. In the present exemplary embodiment, a fan 7 is assigned to the hot-gas section 5, and a fan 8 is assigned to the low-temperature section 6. Both the fan 7 and the fan 8 draw in ambient air 2 from the interior of the vehicle. For example, the air volume flow delivered by the fan 7 can be 350 m³ / h and the air volume flow delivered by the fan 8 can be 500 m³ / h.

[0020] With the help of the fan 8, ambient air is guided past the low-temperature section 6, which, after passing through the low-temperature section 6, is returned to the air conditioning unit 1 as recirculated air 9. The air conditioning unit 1 conditions the temperature and humidity of the recirculated air 9 so that it can be discharged into the interior of the vehicle as ambient air 2. Typically, ambient air 2 is a mixture of the recirculated air 9 and fresh air drawn in from the vehicle's surroundings.

[0021] The room air sucked in by the fan 7 passes through the hot gas section 5 and is then discharged as exhaust air 10 to the outside of the vehicle.

[0022] The interaction of the respectively sucked room air 2 with the low-temperature section 6 and the hot gas section 5 is described in more detail in Figure 2The structure of the heat exchanger, which forms the condenser of the refrigeration circuit of the gas cooler 3, corresponds to that of a cross-counterflow heat exchanger. In the area of ​​a distribution line 11, the temperature of the refrigerant flowing into the hot gas section 5 is 90°C. Between the distribution line 11 and a collector line 12, a line arrangement 13 is provided, in the area of ​​which the hot gas section 5 interacts with room air to cool the refrigerant. As a result, the temperature of the coolant in a collector line 12 is 65°C. This temperature profile for the coolant is also derived from Figure 3, where a curve K1 represents the temperature profile of the coolant and a curve L1 represents a temperature profile for the room air 2, in each case over the distance between the collector line 12 and the distributor line 11. The room air 2 used to cool the coolant in the area of ​​the hot gas section 5 is discharged as the exhaust air 10 after passing through the hot gas section 5. The power of the fan 7 is dimensioned such that approximately 350m 3 / h of room air 2 are sucked in in the area of ​​the hot gas section 5.

[0023] The refrigerant, cooled to a temperature of 65°C in the area of ​​the hot gas section 5, is conveyed by means of a flow line 13 to a distribution line 14 of the low-temperature section 6. A line arrangement 16 is arranged between the distribution line 14 and a collector line 15 of the low-temperature section 6, in the area of ​​which an interaction takes place between the room air 2 and the refrigerant of the cooling circuit of the gas cooler 3. In the area of ​​the collector line 15, the coolant temperature in the example explained here is 45°C. The room air 2, which has passed through the low-temperature section 6, is supplied to the air conditioning unit 1 as recirculated air 9 for post-treatment.

[0024] Figure 4 shows schematically the temperature curves K2 and L2 for the refrigerant and the room air in the area of ​​the low-temperature section 6.

[0025] In both the hot gas section 5 and the low-temperature section 6, the temperature of the drawn-in room air is 32°C. The temperature of the recirculated air 9 is 36°C, so that the air conditioning unit 1, which provides the room air 2 for the interior of the vehicle, only needs to provide comparatively little cooling power to provide a desired target temperature for the room air 2 introduced into the passenger compartment.

[0026] The Figures 5 , 6 , 7, 8 illustrate a second embodiment in which, compared to the first embodiment, only the type of intake of the room air 2 in the area of ​​the hot gas section 5 and the type of guidance of the circulating air 9 from the low-temperature section 6 to the air conditioning unit 1 are changed.

[0027] In contrast to the first embodiment, the air conditioning arrangement according to Figure 5A fan for directly sucking in room air 2 for the hot gas section 5 is omitted. Instead, room air 2 is sucked in exclusively by the fan 8, which is assigned to the low-temperature section 6. All sucked-in room air 2 is guided toward the hot gas section 5 after passing through the low-temperature section 6. However, an air distribution device 17, which can be designed as a baffle, is arranged on this flow path. This air distribution device 17 extracts a portion from the air flow coming from the low-temperature section 6, which is to be fed to the air conditioning unit 1 as the recirculated air 9. A portion of the air flow coming from the low-temperature section 6 that is not extracted is fed to the hot gas section 5 and leaves the gas cooler 3 as the exhaust air 10.

[0028] As from Figure 6As can be seen, the fan 8, for example, sucks in an air volume flow of 1000m 3 < / h, after leaving the low-temperature section 6 a portion of 650m 3 < / h is coupled out as recirculated air 9, while the remaining 350m 3 < / h are fed to the hot gas section 5 and leave this as the exhaust air 10.

[0029] For the temperature curves of the coolant and the air passing through the hot gas section 5, the curves K3, L3 result from Figure 7 The conditions at low-temperature section 6 are based on Figure 8 , see temperature curves K4, L4. It can be seen that at the distributor line 11 of the hot gas section 5, the coolant has a temperature of 90°C, which, after interaction with the exhaust air flow 10, has dropped to 65°C in the area of ​​the collector line 12 of the hot gas section 5. In the area of ​​the low-temperature section 6, the coolant temperature drops from 65°C to 45°C.

[0030] The curve L4 of Figure 8illustrates that the temperature of the air flow after passing through the low-temperature section 6 is 34°C. This is the temperature that is then approximately present at the air conditioning unit 1 for the recirculating air 9. Compared to the first exemplary embodiment, the recirculating air temperature is thus 2°C lower, so that the performance requirements of the air conditioning unit 1 for conditioning the recirculating air 9 are overall more favorable.

Claims

1. Air conditioning arrangement for an interior of a vehicle, with a climate control unit (1) for providing air-conditioned ambient air (2) and a cooling unit arranged in the interior which has a cooling circuit (4), which has a heat exchanger for cooling a refrigerant of the cooling circuit (4), said heat exchanger being applied with ambient air (2), characterised in that the heat exchanger is spatially divided into a hot gas portion (5) and into a low temperature portion (6), the ambient air (2) drawn in in order to cool the heat exchanger is divided into an exhaust air portion (10) and a circulating air portion (9), wherein the low temperature portion (6) of the heat exchanger is applied with the circulating air portion (9) of the ambient air (2) and the hot gas portion (5) of the heat exchanger is applied with the exhaust air portion (10) of the ambient air (2).

2. Air-conditioning arrangement according to claim 1, characterised in that the heat exchanger is embodied as a cross counterflow heat exchanger.

3. Air-conditioning arrangement according to claim 1 or 2, characterised in that the hot gas portion (5) and the low temperature portion (6) of the heat exchanger adjoin one another directly.

4. Air-conditioning arrangement according to one of claims 1 or 2, characterised in that the hot gas portion (5) and the low temperature portion (6) of the heat exchanger are spatially separated from one another.

5. Air-conditioning arrangement according to one of claims 1 to 4, characterised in that a fan (7) for drawing in the exhaust air portion (10) from the ambient air (2) is assigned to the hot gas portion (5) and a fan (8) for drawing in the circulating air portion (9) from the ambient air (2) is assigned to the low temperature portion (6).

6. Air-conditioning arrangement according to one of claims 1 to 4, characterised in that an air distribution facility arranged between the hot gas portion (5) and the low temperature portion (6) is provided which divides drawn-in ambient air (2) into the exhaust gas portion (10) and the circulating air portion (9).

7. Air-conditioning arrangement according to one of claims 1 to 6, characterised in that the volume flow of the exhaust air portion (10) is dimensioned smaller than the volume flow of the circulating air portion (9).

8. Air-conditioning arrangement according to claim 7, characterised in that the volume flow of the exhaust air portion (10) is less than 40% of the volume flow of the drawn-in ambient air (2).

9. Air-conditioning arrangement according to one of claims 1 to 8, characterised in that the cooling unit is designed as a gas cooler (3), in which the hot gas portion (9) and the low temperature portion (6) are each embodied generally to be rectangular.