Patent Application
20250102239
This application claims priority from German Patent Application No. DE 10 2023 125 716.1, filed Sep. 22, 2023, the entirety of which is hereby fully incorporated by reference herein.
The invention relates to a heat exchanger, preferably for a motor vehicle, and the use of the heat exchanger in an air conditioner for a motor vehicle.
DE 199 35 688 A1 discloses such a heat exchanger for use in a motor vehicle. This heat exchanger for motor vehicles, in particular a coolant cooler, contains a block (finned tube block) of tubes (flat tubes), in which a liquid and/or gaseous medium flows, and corrugated fins through which air flows connected thereto, as well as at least one collector plate (tube plate) into which the ends of the tubes open, and are brazed to passages in the collector plate. This heat exchanger must withstand temperature fluctuations. These temperature fluctuations change the size and shape of the block and collectors in the heat exchanger. When the block becomes hotter or colder, the length of the tubes changes, making the tubes, particularly in the outermost rows, more likely to crack or break, resulting in undesired leakage. The invention provides that at least two tubes are connected to one another by a bracket, and the bracket is brazed to the ends of the tubes. A baffle (where the direction in which a medium flowing through the tubes changes) is placed in the brackets connecting pairs of tubes in the collector or block. This heat exchanger has more than one flow path, and can contain numerous rows of tubes. The brackets make at least part of the walls of the tubes and the collector thicker, and thus have a negative effect on how the medium flows through the tubes. This has a negative impact on the performance of the heat exchanger. The collector, brackets, and tubes can be made of a metal such as aluminum. Because the brackets change the thickness of the walls of the tubes and collector, there is a higher possibility of cracking or breakage near the collector or baffle. The use of these brackets results in fluctuations in the rigidity of the collector plate that have a negative impact.
It is also possible to seal off individual tubes. No medium flows through the sealed tubes, for which reason the lengths thereof do not change due to temperature fluctuations, because they do not become hotter or colder, thus limiting the changes to the shape and size of the heat exchanger. This increases the durability of the heat exchanger. Sealing some of the tubes has a negative impact on the performance of the heat exchanger, however, because these tubes no longer participate in heat transfer.
A heat exchanger with baffles in the collector which have a hole for a defined leakage of the medium is also conceivable. This results in small amounts of the medium flowing past the tubes at the baffles, and less medium flowing through the tubes. This reduces the amount of heat to the tubes and therefore the thermal expansion thereof. This increases the durability of the heat exchanger. The reduction in medium flowing through the tubes has a negative impact on the performance of the heat exchanger, however.
It would also be possible to use a heat exchanger that has a collector with two collector plates placed one above the other. Because this results in a thicker collector plate, the durability of the heat exchanger, specifically the collector, is improved. This has the negative effect of increasing the amount of material and difficulty involved in the production of the heat exchanger.
The apparatus according to the invention, which has the features of the independent claim, has the advantage that the heat exchanger is more durable when subjected to temperature fluctuations, without any reduction in the performance thereof.
The basis for the invention is a heat exchanger, preferably for a motor vehicle. The heat exchanger obtained with the invention has numerous tubes. There are corrugated fins between the tubes. The tubes can be flat tubes. The corrugated fins can be connected to the tubes to form a block. A first medium can flow through the tubes, and a second medium can flow between the corrugated fins, thus enabling heat transfer between the first and second media. The heat exchanger according to the invention has at least one collector. The at least one collector has at least one baffle, with a reinforcement plate adjacent thereto. This at least one reinforcement plate has at least one hole. The heat exchanger can have two collectors in a first embodiment. A gaseous and/or liquid medium can flow through the heat exchanger. The block composed of tubes and corrugated fins can be placed between the two collectors. The tubes can be placed next to one another in one or more rows. The vertical axis can run along the length of the tubes. The direction in which the medium flows can be reversed at the at least one baffle. This reversal in the direction in which the medium flows can increase the load to the area next to the baffles. This may reduce the durability of the heat exchanger in these areas. Durability is understood to refer to the mechanical load a component can withstand before it fails. Breakage or extensive deformation can result in this failure. The temperature of the heat exchanger changes when in use due to the heat it is exposed to, and the heat it discharges. Changes in temperature result in a thermal expansion of the heat exchanger, thus altering the geometrical size of the heat exchanger obtained with the invention. This is a thermal fluctuation in the load to which the heat exchanger according to the invention is subjected. This thermal fluctuation determines in part the durability of the heat exchanger. When the block is heated or cooled, the length of the tubes changes due to thermal expansion, increasing the probability of cracks or breakage, in particular where the tubes are connected to the collectors near the baffles. These cracks or breaks in the tubes can result in undesired leakage. The areas adjacent to the baffles are subject to loads from the first medium through changes in the flow or flow rate. Moreover, changes in the rigidity of the collector caused by the baffles can also result in higher loads to these areas. This can significantly reduce the durability of the heat exchanger. The rigidity of a component depends on the material it is made of and its shape, thus describing the relationship between its resistance to deformation caused by a load. The rigidity describes the relationship between the load to the heat exchanger due to temperature fluctuations and the deformation of the heat exchanger.
The chance of breakage or cracking near the at least one baffle can advantageously be reduced by placing a reinforcement plate next to the at least one baffle. This not only increases the rigidity of the collector, but also reduces changes in the rigidity of the collector. Consequently, the heat exchanger can withstand greater thermal fluctuations near the at least one baffle. The durability of the heat exchanger is advantageously increased, and undesired leakages can be prevented by this means. Because the at least one reinforcement plate has at least one hole, there is no, or negligible, change to the flow of the first medium through the heat exchanger. The at least one reinforcement plate is placed between two tubes in the at least one collector. Consequently, the medium can flow freely through the at least one reinforcement plate to or from the tubes. This allows the medium to flow through of the tubes. The performance of the heat exchanger with regard to transferring heat from one medium to another is not affected or reduced by the use of the at least one reinforcement plate, because the at least one reinforcement plate has no substantial effect on the flow of the medium through the tubes. In a second embodiment of the heat exchanger, the at least one reinforcement plate can have two holes. This further reduces or even prevents any losses in the flow rate caused by the at least one reinforcement plate.
In a third embodiment of the heat exchanger according to the invention, there can be at least one tube between the at least one baffle and the at least one reinforcement plate.
This further increases the durability of the heat exchanger, because it can prevent significant changes in the rigidity of the heat exchanger or collector that have a negative impact.
In another embodiment of the heat exchanger according to the invention, two tubes can be placed between the at least one baffle and at least one reinforcement plate. The distance between the at least one baffle and at least one reinforcement plate can be the width of two tubes. This further increases the durability of the heat exchanger, because it can further reduce significant changes in the rigidity of the heat exchanger or collector that have a negative impact.
In another embodiment of the heat exchanger according to the invention, the heat exchanger can have a length. The length can run along the longer side of the collector. The at least one reinforcement plate can be in front of or behind the at least one baffle along this length. This can advantageously further increase the durability of the heat exchanger.
In another embodiment of the heat exchanger according to the invention, there can be a reinforcement plate both in front of and behind the at least one baffle along the length. The reinforcement plates can be spaced apart by two tubes. The heat exchanger according to the invention can therefore have two reinforcement plates for each baffle in a collector. If the heat exchanger has two collectors, each of which has two baffles, there are then a total of four baffles and eight reinforcement plates. This further increases the durability of the heat exchanger.
In another embodiment of the heat exchanger according to the invention, the heat exchanger can have at least two flow paths. A heat exchanger with a specific number of tubes and corrugated fins has a specific performance level. A medium can flow through the tubes in the heat exchanger. To increase the performance of the heat exchanger, the flow path for the medium through the heat exchanger can be divided into two flow paths. This increases the distance the medium flows through the heat exchanger, thus increasing the surface area available for heat exchange. This division into at least two flow paths can be obtained through the use of at least one baffle in a collector. The heat exchanger according to the invention can be divided into more flow paths by using more than one baffle in the collectors. This further improves the performance of the heat exchanger. Improving the performance of the heat exchanger can also result in an increase in the load due to thermal fluctuation, thus reducing the durability of the heat exchanger. By placing at least one reinforcement plate next to the at least one baffle, the durability of the heat exchanger can be increased such that it can withstand these increases in thermal fluctuation loads caused by the division of the flow path. A single flow path can be formed by numerous tubes or a single tube in the heat exchanger.
In another exemplary embodiment, the heat exchanger according to the invention can contain two collectors, each of which has two baffles. A reinforcement plate can be placed in front of and behind each baffle, such that each collector has four reinforcement plates. The heat exchanger can thus have three flow paths.
In another embodiment of the heat exchanger according to the invention, the at least one collector can have a collector plate with passages formed therein. The tubes then open into these passages. This connects the collector to the tubes for fluid exchange. The tubes can be flat tubes, and the passages can be elongated. The at least one collector can have a lid. The collector plate, lid, and tubes can be connected to one another, such that they are sealed off against the environment. The at least one baffle can be between two passages in the at least one collector, and the at least one reinforcement plate can be adjacent to the at least one baffle, between two passages. By placing the at least one reinforcement plate next to the at least one baffle in the at least one collector, the rigidity of the collector, or heat exchanger, can advantageously be increased, and/or changes in the rigidity can be prevented, thus preventing leaks and cracks due to thermal fluctuations. The at least one baffle and at least one reinforcement plate can each have an upper ledge on top. These upper ledges can be connected to a recess in the collector lid. The at least one baffle and at least one reinforcement plate can have one or more lower ledges at the bottom. These ledges on the at least one baffle and at least one reinforcement plate fit the shape of the collector plate to obtain a reliable bond between them. “Sealed” means that no medium, or only a negligible amount of medium, can pass through the bond.
In another embodiment of the heat exchanger according to the invention, the at least one reinforcement plate can be connected to two passages. The at least one collector can have a collector plate with passages. The tubes can open into the passages. The at least one reinforcement plate can fit between two passages. There can also be a gap between the each side of the reinforcement plate and the adjacent passage. It is also conceivable that the reinforcement plate fits tightly between the two passages. A gap is the space between two components. If there is a gap, the two components are spaced apart, and if there is no gap, the one component can be secured in place. The at least one reinforcement plate can be materially bonded to the collector plate between the two passages. Prior to obtaining this bond, there is a gap between the at least one reinforcement plate and the two passages. The at least one reinforcement plate could also be force-fit between the two passages in the collector plate. This further increases the rigidity of the collector and thus advantageously further increases the durability of the heat exchanger, or collector.
In another embodiment of the heat exchanger according to the invention, a first medium can flow through the tubes and at least one collector. The direction this first medium flows in can be reversed by the at least one baffle. The heat exchanger can have a height, length, and width. The height can run along the length of the tubes, and the width can run along the shorter side of the heat exchanger. The length can run along the at least one collector. The direction in which the first medium flows can be reversed by a baffle. This reversal can be in the vertical direction. Alternatively, the reversal in the flow of the first medium can be along the length. It can also be reversed laterally, along the width. The at least one baffle can result in more than one flow path through the heat exchanger. The distance the first medium flows through the heat exchanger can be increased in this manner. This can improve the performance of the heat exchanger, because it increases the available surface area for heat exchange. The first medium can contain gaseous and/or liquid portions. The first medium can be a refrigerant. Carbon dioxide (R744) can be used for the first medium. The refrigerants R1234yf, R1234a, or R290 can also be used. A second medium can flow between the corrugated fins. The second medium can flow in a direction transverse to the corrugated fins and tubes. The second medium can be air. The first medium transfers heat to the second medium through the surfaces of the corrugated fins and the tubes.
The heat exchanger according to the invention can be used in this manner as a direct heat exchanger.
In another embodiment of the heat exchanger according to the invention, the first medium can flow through the at least one hole in the at least one reinforcement plate. The use of the at least one reinforcement plate can therefore also prevent, or at least reduce, pressure losses or flow losses in the at least one collector, or in the flow paths in the heat exchanger.
In another exemplary embodiment of the heat exchanger according to the invention, the at least one reinforcement plate can have two holes. This can further increase the rigidity of the at least one collector or heat exchanger, thus advantageously further increasing the durability. The first medium can flow through the two holes. By using two holes in the at least one reinforcement plate, an inadvertent increase in pressure losses or flow losses in the at least one collector, or in the flow paths in the heat exchanger, can at least be reduced.
The heat exchanger according to the invention has at least one row of tubes. In another embodiment according to the invention, the heat exchanger can have one row of tubes.
The tubes can be in a row extending along the length. The heat exchanger can have more than one flow path obtained through the use of baffles.
In another embodiment according to the invention, the heat exchanger can have two rows of tubes. The tubes in one row can be placed successively along the length. The second row of tubes can be parallel to the first row laterally. The performance of the heat exchanger can be improved by using numerous rows of tubes. This is because more surface area is available for heat exchange. The first medium may flow into the heat exchanger at a higher temperature. This can result in large, undesired differences in the temperature profile of the heat exchanger. These differences in the temperature profile can diminish the performance of the heat exchanger, or reduce the comfort level for the vehicle passengers. The heat exchanger according to the invention can contain numerous flow paths. The flow paths can comprise numerous tubes or just one tube. A single flow path can comprise numerous tubes in a single row, or tubes in numerous parallel rows of tubes. Potential irregularities in the temperature profile of the heat exchanger can be compensated for by this means.
The heat exchanger according to the invention contains a metallic substance. This can be an aluminum alloy. The tubes, corrugated fins, at least one collector, at least one baffle, and at least one reinforcement plate can each contain an aluminum alloy. The heat exchanger according to the invention could also contain a copper alloy.
In another exemplary embodiment of the heat exchanger according to the invention, the at least one baffle and at least one reinforcement plate can be materially bonded to the at least one collector. The tubes and corrugated fins can also be bonded to one another. The tubes can open into the passages in the collector plate. The passages and tubes can be bonded to one another. The at least one baffle and at least one reinforcement plate can be bonded to the passages. The at least one collector can have an intake line and/or discharge line. The collector plate, lid, and intake and/or discharge lines can be bonded to one another. The heat exchanger can contain an aluminum alloy. All of the components can be bonded to one another and the at least two flow paths in the heat exchanger according to the invention can be sealed off from the environment by this means. The individual components can be brazed to one another.
In another exemplary embodiment of the heat exchanger according to the invention, the at least one baffle and at least one reinforcement plate can be connected to the at least one collector with a force-fitting connection. The at least one reinforcement plate and at least one baffle can be connected to the collector with an interference fit assembly. The interference fit assembly can be obtained between two passages in the collector plate and the at least one baffle or at least one reinforcement plate.
In another exemplary embodiment of the heat exchanger according to the invention, the at least one baffle and at least one reinforcement plate can be connected to the at least one collector with a material bond and a force-fitting connection. The at least one reinforcement plate and at least one baffle can be connected to the at least one collector with a press fit assembly, before the heat exchanger is brazed in an oven to obtain the material bond.
A first use of the heat exchanger according to the invention can be in a refrigerant circuit in a motor vehicle. The refrigerant circuit for a motor vehicle can be used in an air conditioner, for example. The air conditioner can have a housing, at least one channel for a second medium, at least one fan, and a heat exchanger according to the invention, forming part of the refrigerant circuit for cooling the second medium that is to be conducted into the vehicle interior. The heat exchanger according to the invention can be used as a condenser. The heat exchanger can be the first embodiment presented in the description of the invention. The first medium, a refrigerant, can flow through the refrigerant circuit. The first medium can be carbon dioxide (R744). The refrigerants R1234yf, R1234a, or R290 (propane) could also be used. The first medium can flow through the tubes in the heat exchanger according to the invention, and the second medium can flow between the corrugated fins. By condensing the first medium (refrigerant) in the second medium (air), heat can be generated in or removed from the heat exchanger. Thermal expansion of the tubes and corrugated fins can alter the size and shape of the heat exchanger. This can result in fluctuations in the thermal load to the heat exchanger. By placing at least one reinforcement plate next to a baffle in the collector, the durability of the heat exchanger can be improved, such that it can withstand these thermal fluctuations. The refrigerant circuit can be composed of a vaporizer, expansion mechanism, the heat exchanger according to the invention, forming a condenser, and the connecting lines.
A second use of the heat exchanger according to the invention can be in a coolant circuit for a motor vehicle. Excess heat generated by the motor vehicle can be discharged through the coolant circuit into the environment via the heat exchanger. The heat exchanger can be the first embodiment presented in the description of the invention. The motor vehicle can have a partially or entirely electric drive. In this case it may be necessary to quickly discharge large amounts of heat from the battery or electric motor. This can result in large changes to the size and shape of the heat exchanger. The thermal expansion of tubes and corrugated fins can result in large thermal fluctuations in the heat exchanger. By placing at least one reinforcement plate next to a baffle in the collector, the durability of the heat exchanger can be improved, such that it can withstand the larger thermal fluctuations. A coolant, forming the first medium, can flow through this coolant circuit. This coolant can be G13. The second medium can be air.
Another use of the heat exchanger according to the invention can be in a refrigerant circuit in a motor vehicle. The refrigerant circuit can be for an air conditioner. The air conditioner can have a housing, a heat pump, at least one channel for a second medium, at least one fan, and a heat exchanger according to the invention, forming part of the refrigerant circuit for cooling the second medium that is to be conducted into the interior of the motor vehicle. The heat exchanger can be used as a condenser. The heat exchanger can be the first embodiment presented in the description of the invention. The first medium, a refrigerant, can flow through the refrigerant circuit.
Carbon dioxide (R744) can be used for the first medium. The refrigerants R1234yf, R1234a, or R290 could also be used. The heat exchanger can be the first embodiment presented in the description of the invention. The second medium can be air. When driving an entirely, or predominantly electric vehicle, there is no, or very little, heat loss that could be used to heat the vehicle interior. The energy used to power the vehicle can be obtained from batteries. If electric heaters are used to heat the vehicle interior, a lot of electricity is needed from the batteries. This can significantly reduce the travel range of the vehicle. For this reason, the refrigerant circuit can be used to not only cool the second medium, but also to heat the second medium in the heat pump mode. The heat exchanger can be used to draw heat from the ambient air to heat the second medium. The heat exchanger can thus be used as a condenser. Large thermal fluctuations can occur in the heat exchanger due to the heat added to or removed from the heat exchanger resulting in the thermal expansion of the tubes and corrugated fins. By placing at least one reinforcement plate in the collector, the durability of the heat exchanger can be improved, such that it can withstand these thermal fluctuations. The refrigerant circuit can be composed of the heat exchanger according to the invention, functioning as a vaporizer or condenser, a compressor, a second heat exchanger, an expansion valve, and the connecting lines.
The specification can be readily understood with reference to the following Numbered Paragraphs:
Numbered Paragraph 1. A heat exchanger (100), preferably for a motor vehicle, containing:
Numbered Paragraph 2. The heat exchanger (100) according to Numbered Paragraph 1, characterized in that there is at least one tube (RO) between the at least one baffle (TP) and the at least one reinforcement plate (VP).
Numbered Paragraph 3. The heat exchanger (100) according to Numbered Paragraph 1 or 2, characterized in that the heat exchanger (100) has a length (LR), wherein there is a reinforcement plate (VP) in front of and/or behind the at least one baffle (TP) along the length (LR).
Numbered Paragraph 4. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the heat exchanger (100) has at least two flow paths (SP).
Numbered Paragraph 5. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the at least one collector(S) has a collector plate (SB) with passages (DZ), wherein the tubes (RO) open into the passages (DZ).
Numbered Paragraph 6. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the at least one reinforcement plate (VP) is connected to two passages (DZ).
Numbered Paragraph 7. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that a first medium (M1) flows through the tubes (RO) and at least one collector(S), wherein the direction in which the first medium (M1) flows is reversed by the at least one first baffle (TP).
Numbered Paragraph 8. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the first medium (M1) flows through the at least one hole (O) in the at least one reinforcement plate (VP).
Numbered Paragraph 9. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the heat exchanger (100) contains at least one row of tubes (RO).
Numbered Paragraph 10. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the heat exchanger (100) contains a metallic substance.
Numbered Paragraph 11. The heat exchanger (100) according to any of the preceding Numbered Paragraphs, characterized in that the at least one baffle (TP) and at least one reinforcement plate (VP) are bonded and/or force-fit to the at least one collector(S).
Numbered Paragraph 12. The heat exchanger (100) for a refrigerant circuit or coolant circuit in a motor vehicle according to any of the preceding Numbered Paragraphs 1 to 11.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102023125716.1 | Sep 2023 | DE | national |
