HEAT EXCHANGER UNIT

Abstract

A heat exchanger unit for a fluid circuit of a motor vehicle includes a plurality of fluid connections for a through-flow of a working fluid, a fluid distributor fluidically connected to the fluid connections, and a fluid connector fluidically connected to the fluid connections. The fluid distributor is structured and arranged to distribute the working fluid among the fluid connections, and the fluid collector is structured and arranged to collect the working fluid after flowing through the fluid connection. At least a portion of the fluid distributor and/or the fluid collector includes a surge tank for the working fluid.

Claims

1. A heat exchanger unit for a fluid circuit of a motor vehicle, comprising: a plurality of fluid connections for a through-flow of a working fluid, a fluid distributor fluidically connected to the plurality of fluid connections, structured and arranged to distribute the working fluid among the plurality of fluid connections, a fluid collector fluidically connected to the plurality of fluid connections, structured and arranged to collect the working fluid after flowing through the plurality of fluid connections, and wherein at least a portion of at least one of the fluid distributor and the fluid collector includes a surge tank for the working fluid.

2. The heat exchanger unit according to claim 1, wherein the heat exchanger unit is a direct condenser unit or an indirect condenser unit.

3. The heat exchanger unit according to claim 1, wherein: the fluid distributor has a fluid inlet for an inflow of the working fluid, the fluid collector has a fluid outlet for an outflow of the working fluid, wherein the surge tank is provided in at least the portion of the fluid collector, and wherein the fluid distributor has a cross section having a maximum value at the fluid inlet and that decreases with increasing distance from the fluid inlet.

4. The heat exchanger unit according to claim 1, wherein: the fluid collector includes a cover and a bottom (11), a fluid-tight membrane is arranged between the cover and the bottom, a first spatial region is disposed between the cover and the membrane, a second spatial region is disposed between the membrane and the bottom, and wherein the second spatial region is fluidically connected to the plurality of fluid connections.

5. The heat exchanger unit according to claim 4, wherein: a fluid-permeable separating element is disposed in the second spatial region between the membrane and the bottom, and the fluid-permeable separating element is structured and arranged to a pre-spatial region between the separating element and the bottom into which the membrane is blocked from penetrating.

6. The heat exchanger unit according to claim 4, wherein: the second spatial region is structured and arranged to maintain a liquid level of the working fluid therein within a predefined level range during normal operation, and wherein a fluid outlet of the fluid collector is arranged below the predefined level range.

7. The heat exchanger unit according to claim 6, wherein: the fluid collector includes an additional condenser unit, and wherein the additional condenser unit is arranged above the fluid outlet during operation.

8. The heat exchanger unit according to claim 7, wherein the additional condenser unit has a circuit that is filled with a working medium.

9. The heat exchanger unit according to claim 7, wherein: the additional condenser unit includes a tank with a working medium, wherein the working medium flows once through the additional condenser unit after a switching process and then escapes into the surroundings.

10. A fluid circuit of a motor vehicle, comprising: a heat exchanger unit, the heat exchanger unit including: a plurality of fluid connections communicating a through-flow of a working fluid; a fluid distributor fluidically connected to the plurality of fluid connections, structured and arranged to distribute the working fluid among the plurality of fluid connections; a fluid collector fluidically connected to the plurality of fluid connections, structured and arranged to collect the working fluid from the plurality of fluid connections a surge tank for the working fluid provided in at least a portion of the fluid collector; a fluid outlet for an outflow of the working medium; wherein the fluid collector includes a fluid-tight membrane disposed therein that separates a first spatial region from a second spatial region; wherein the second spatial region is fluidically connected to the plurality of fluid connections, and structured and arranged to hold a liquid phase of the working medium at a liquid level of a predefined level range during operation; and wherein the fluid outlet is arranged below the predefined level range; a fluid delivery device disposed downstream from the fluid outlet and wherein the fluid delivery device is structured and arranged to only deliver a liquid phase of the working fluid.

11. A method for operating a fluid circuit, comprising: delivering a mass flow of a liquid phase of a working medium via a fluid delivery device arranged downstream from a fluid outlet of a heat exchanger unit, and interrupting the mass flow delivered by the fluid delivery device upon inadequate condensation of the working fluid in the heat exchanger unit; and halting operation of the fluid circuit upon interrupting the mass flow delivered by the fluid delivery device.

12. The method according to claim 11, the mass flow delivered by the fluid delivery device is interrupted upon inadequate condensation of the working fluid in the heat exchanger unit the fluid delivery device substantially drawing in a gaseous phase of the working fluid.

13. The fluid circuit according to claim 10, wherein the heat exchanger unit is a direct condenser unit.

14. The fluid circuit according to claim 10, wherein the heat exchanger unit is an indirect condenser unit.

15. The fluid circuit according to claim 10, wherein the fluid outlet is provided at the fluid collector, and wherein the fluid distributor has a fluid inlet for an inflow of the working fluid into the heat exchanger unit.

16. The fluid circuit according to claim 15, wherein the fluid distributor has a cross section with a maximum value at the fluid inlet and decreases with increasing distance from the fluid inlet.

17. The fluid circuit according to claim 10, wherein the fluid collector further includes a cover and a bottom, wherein the first spatial region is disposed between the cover and the membrane, and the second spatial region is disposed between the membrane and the bottom.

18. The fluid circuit according to claim 17, wherein the fluid collector further includes a fluid-permeable separating element disposed in the second spatial region between the membrane and the bottom.

19. The fluid circuit according to claim 10, wherein the fluid collector further includes an additional condenser unit, and wherein the additional condenser unit is arranged above the fluid unlet in an installed position of the heat exchanger unit.

20. The fluid circuit according to claim 19, wherein the additional condenser unit has a circuit or a tank filled with a working medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings show, each case schematically,

[0031] FIG. 1 an internal combustion engine with a fluid circuit according to the invention,

[0032] FIG. 2 a fluid circuit according to the invention with additional condenser unit,

[0033] FIG. 3 a first embodiment of an indirect heat exchanger unit according to the invention,

[0034] FIG. 4 a second embodiment of an indirect heat exchanger unit according to the invention,

[0035] FIG. 5 a third embodiment of an indirect heat exchanger unit according to the invention.

DETAILED DESCRIPTION

[0036] FIG. 1 shows symbolically a motor vehicle 3, having a fluid circuit 2 and an internal combustion engine 24, the fluid circuit 2 being thermally coupled to the internal combustion engine 24 in such a way that the fluid circuit 2 removes waste heat of the internal combustion engine 24 into the surroundings of the motor vehicle 3. In FIG. 1-5, fluid lines are marked by arrows, joining together each time two components of the motor vehicle 3, the arrow direction representing the flow direction of a working fluid in the fluid circuit 2.

[0037] The fluid circuit 2 comprises a heat exchanger unit 1, a fluid delivery device 21, an evaporator unit 22 and an expander unit 23. These components are interconnected by fluid lines in such a way that they form the closed fluid circuit 2, in which the working fluid is circulating.

[0038] The heat exchanger unit 1 comprises a fluid distributor 5 (entry box) and a fluid collector 6 (exit box), the fluid distributor 5 and the fluid collector 6 being spaced apart from each other. The fluid distributor 5 and the fluid collector 6 are fluidically connected by a plurality of fluid connections 4. The fluid connections 4 may be formed as flat tubes, for example. Between the fluid connections 4 there may be provided rib elements, in order to maximize the surface contributing to the heat exchange.

[0039] The fluid distributor 5 has a fluid inlet 8, through which the working fluid can flow into the fluid distributor 5. As indicated in FIG. 1, the cross section of the fluid distributor 5 decreases with increasing distance from the fluid inlet 8.

[0040] The working fluid coming from the expander unit 23 is substantially gaseous and it flows through the fluid connections 4, becoming cooled and condensing. The thermal energy released by the working fluid is discharged via the fluid connections 4 to the surroundings of the heat exchanger unit 1.

[0041] The fluid collector 6 comprises a cover 10 and a bottom 11, wherein between the cover 10 and the bottom 11 there is arranged a fluid-tight and elastic membrane 12. Between the cover 10 and the membrane 12 there is formed a first spatial region 13, while between the membrane 12 and the bottom 11 there is formed a second spatial region 14, the second spatial region 14 being fluidically connected to the fluid connections 4. In the second spatial region 14 there is provided a separating element 15, which is permeable to the working fluid and impermeable to the membrane 12. The separating element 15 forms, together with the bottom 11, a pre-spatial region 16 into which the membrane 12 cannot penetrate. In this way, the membrane 12 is prevented from closing the fluid connections 4 or a fluid outlet 9 in event of a negative pressure. The separating element 15 may be formed for example as a grid element. Depending on the system pressure, the membrane 12 stretches in the direction of the cover 10 or in the direction of the bottom 11.

[0042] The liquid working fluid gathers in the surge tank 7, which is formed by the membrane 12 and the bottom 11. As shown in FIG. 2, the liquid working fluid in normal operation of the heat exchanger unit 1 has a liquid level 17 lying in a level range 18. The level range 18 is indicated in FIG. 1 and FIG. 2 by dotted wavy lines. The level range 18 may be defined by a minimum level 28 and a maximum level 27. The liquid level 17 is indicated by a solid wavy line. The fluid outlet 9 is situated below the level range 18, wherein it may be provided that the fluid outlet 9 is situated at the lower region of the level range 18.

[0043] If the liquid level 17 drops significantly below the level range 18, i.e., below the minimum level 28, the fluid delivery device 21 can no longer take in any liquid working fluid, but only gaseous working fluid. Since the fluid delivery device 21 is designed so that it can only deliver liquid working fluid, the mass flow of the working fluid in the fluid circuit 2 breaks down, so that the fluid circuit 2 shuts itself off.

[0044] The fluid circuit 2 in FIG. 2 differs from the fluid circuit 2 in FIG. 1 in that an additional condenser unit 19 has been assigned to the surge tank 7, the fluid connections between the surge tank 7 and the additional condenser unit 19 being situated above the liquid level 17 and/or above the fluid outlet 9. Hence, only gaseous working fluid can flow into the additional condenser unit 19 and become condensed there. Upon condensation of the working fluid, a working medium of the additional condenser unit 19 is evaporated. The additional condenser unit 19 may comprise a tank 20 in which the working medium is kept ready for a repeat or even a onetime use. In addition, the surge tank 7 comprises a safety valve 26, via which the gaseous working fluid can be discharged to the surroundings at critical system pressure.

[0045] FIG. 3 shows an embodiment of an indirect heat exchanger unit 1 according to the invention, the heat exchanger unit 1 having a fluid inlet 8 and a fluid outlet 9, between which the working fluid condenses, the condensed working fluid being partly collected in the surge tank 7. The surge tank 7 is fluidically connected by a cavity to a condenser of the heat exchanger unit 1. The surge tank 7 has a compressed air port 25, which can be designed to control the system pressure.

[0046] FIG. 4 shows an embodiment of an indirect heat exchanger unit 1 according to the invention, where the fluid outlet 9 is arranged at the surge tank 7. FIG. 5 shows another embodiment of an indirect heat exchanger unit 1 according to the invention, where an elastic membrane 12 is arranged in the surge tank 7.