Device for transferring thermal energy to fluid

Abstract

The invention relates to a device (1) for transferring thermal energy to a fluid, comprising a heat exchanger (2) which is arranged in a flow path (4) spatially delimited by a housing (3), the heat exchanger (2) having a plurality of flow channels (6) through which a flow can flow in a main flow direction (5), the heat exchanger (2) having a heat storage capability, the heat storage capacity can be utilized to temporarily store thermal energy, in which a fluid having a relatively higher energy and a fluid having a relatively lower energy alternately flow through the heat exchanger (2). The invention further relates to a method for using said device (1).

Description

Technical Field

[0001] The present invention relates to a device for transferring or transmitting thermal energy into or to a fluid (heat regenerator), comprising a heat exchanger arranged in a flow path spatially delimited by a housing. The heat exchanger has a plurality of flow channels through which flow can flow in a main flow direction. The heat exchanger has a heat storage capacity with which a predetermined amount of thermal energy can be temporarily stored.

[0002] Furthermore, the invention relates to a method of using the device. Background Art

[0003] In addition to traditional heat exchangers (regenerators), regenerators can also be used for heat exchange or heat recovery between two fluids. They essentially consist of a porous or channeled heat reservoir. During the heating phase, a first, or hot, fluid flows through the reservoir, heating it. Simultaneously, the (first) fluid cools. During the cooling phase, the reservoir releases the stored heat to a second, or cold, fluid.

[0004] This technology is commonly used, for example, in the ventilation of buildings or enclosed spaces. So-called push-pull heat exchangers, such as those used for building ventilation, consist of a pipe line containing a channeled ceramic element serving as a heat reservoir and a fan with switchable delivery direction. This unit, installed in the building's exterior wall, alternately conveys (especially hot) indoor air (exhaust air) to the outside and, after switching delivery direction, conveys (especially cold) outdoor air (fresh air) back into the room. This utilizes the heat in the exhaust air to preheat the fresh air.

[0005] For efficient heat recovery, good heat transfer between the heat reservoir and the fluid must be ensured. Decisive for this are the surface area available for heat exchange and the heat transfer coefficient of the flow within the heat exchanger. The duration of the heat exchanger heating or cooling must be adapted to the heat capacity of the heat reservoir, for example to avoid pumping more (especially hot) exhaust gas through the heat reservoir even when the maximum heat capacity is reached.

[0006] The heat storage devices known in the prior art for such heat exchangers are typically made of ceramic materials. This is disadvantageous, for example, due to high manufacturing costs. Furthermore, ceramics possess properties that are undesirable for use in building or vehicle ventilation systems, such as resistance to high temperatures and corrosive media. Furthermore, the design options for channel geometry are severely limited, negatively impacting the level of heat transfer between the fluid and the substrate, the potential efficiency, and the operating range of the heat exchanger. Another disadvantage is the adsorption and desorption of air humidity in porous ceramics. This is particularly prevalent near the dew point.

[0007] To heat or cool the interior of a purely electric vehicle, the required energy must be drawn from the vehicle battery. This reduces the vehicle's range at high or low outside temperatures. Heat exchangers (e.g., regenerators) can also be used to minimize energy consumption and thus extend the range. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a device which at least partially solves the problems described in the prior art, in particular enabling thermal energy transfer between fluids, in particular from a fluid with a higher energy level to a fluid with a lower energy level.

[0009] These objects are achieved by the features of the independent claims. Advantageous developments are described in the dependent claims. The features listed individually in the claims can be combined with each other and / or with the facts of the description as desired. The description, in particular in conjunction with the drawings, explains the invention and presents additional embodiment variants.

[0010] The present invention proposes a device for transferring thermal energy into a fluid or for transmitting thermal energy to a fluid, the device comprising a heat exchanger, which is arranged in a flow path spatially delimited by a housing, wherein the heat exchanger has a plurality of flow channels through which flow can flow in a main flow direction, wherein the heat exchanger has a heat storage capacity, due to which thermal energy, in particular a predetermined amount of thermal energy, can be temporarily stored, wherein a fluid with relatively high energy and a fluid with relatively low energy alternately flows or can flow through the heat exchanger.

[0011] The amount and / or duration of temporarily storable thermal energy can be predetermined or limited depending on the operating conditions of the production. Specifically, components can be provided by which the flow through the device in terms of time and / or volume flow can be predetermined, thereby also predetermining or limiting the required thermal storage capacity of the heat exchanger.

[0012] The device can be used, for example, for ventilation and / or temperature control of buildings, or for ventilation and / or temperature control of the interior space of a motor vehicle. The flow path can be formed by a pipeline or, for example, an air duct of a motor vehicle. The heat exchanger is arranged in the flow path so that a fluid, in particular air, can flow through it, or in other words, it is flowable. When the first and / or hot air flows through the heat exchanger, heat or thermal energy can be absorbed by the heat exchanger and at least temporarily stored. Subsequently, when the second and / or cold air is guided through or flows through the heat exchanger, it can absorb the heat or thermal energy temporarily stored in the heat exchanger. Similarly, other energy contained in the fluid, such as the enthalpy of evaporation of atmospheric water, can be temporarily stored in the heat exchanger in the form of heat or thermal energy.

[0013] Therefore, it is possible to absorb heat or thermal energy from the (especially dirty) indoor air and release it to the fresh air input from the outside. This can reduce energy losses during the air exchange process.

[0014] In this case, the heat exchanger can preferably be traversed in opposite directions when releasing heat or thermal energy and when absorbing heat or thermal energy, thereby improving the heat transfer to the air. For releasing heat or thermal energy and for absorbing heat or thermal energy, the heat exchanger can preferably be traversed in opposite directions, thereby improving the heat transfer to the air.

[0015] Depending on the sequence of heat transfer steps, the fresh air brought in from the outside can thus be heated or cooled. In addition to the heat transfer between the outside air and the interior air, the air flow can also be directed over or past heated components, such as the vehicle's power electronics and / or battery, thereby utilizing the waste heat generated there to heat the fresh air for the interior.

[0016] The fluid that can flow through the heat exchanger has a temperature level. The fluid can have a higher energy level and thus be hotter, or a lower energy level and thus be colder. During the flow, heat or thermal energy is transferred from the fluid to the heat exchanger, and when a fluid with a lower energy level subsequently flows through the heat exchanger, the heat or thermal energy is released again from the heat exchanger to the fluid.

[0017] The flow path may include or be fluidically connected to a conveying device, by means of which the fluid can be conveyed through the flow path. A suitable conveying device may be, for example, a fan arranged in the flow path. Alternatively, a fan of a vehicle air conditioner or vehicle ventilation system may be used to guide (particularly in a directional manner) the fluid flow through the heat exchanger.

[0018] The heat exchanger can be formed (at least partially) from a plurality of sheets / foils, wherein the sheets are designed to be at least partially structured and are stacked on top of one another in a layered structure. A preferred embodiment is characterized in that the sheets stacked on top of one another in a layered structure are wound and / or coiled, in particular around at least one axis of rotation.

[0019] In this way, a base body with a large, fluid-wettable surface can be produced, which has a plurality of flow channels between the individual lamellae, through which the fluid can flow. The lamellae then simultaneously serve as heat reservoirs, which absorb heat or thermal energy from a first and / or hot fluid and ultimately release heat or thermal energy to the second and / or cold fluid when a second and / or cold fluid flows through it.

[0020] The lamellae can be made of metal or plastic. Metal or plastic lamellae can be manufactured simply and particularly cost-effectively. The material properties can be easily adapted to the respective application area, thereby enabling the production of heat exchangers precisely tailored to the specific application.

[0021] It is possible that at least one of the sheets is electrically conductive and electrically connected to a voltage source. The electrically conductive sheet can be used to provide additional heating of a fluid flowing past. The sheet can be connected to a voltage source and heated, or heatable, by means of an ohmic resistor. Electrical insulation between the current-carrying sheet / current-carrying sheet and adjacent sheets can be achieved by adjacently arranged, non-conductive sheets. For example, these non-conductive sheets can be made of a non-conductive material or have a non-conductive coating applied thereto.

[0022] The heat exchanger may be made of a composite material, in which a material with relatively high thermal conductivity and a material with relatively low thermal conductivity are used.

[0023] This helps in particular to reduce heat conduction within the carrier material which would reduce the efficiency of the regenerator. Preferably, the materials with higher thermal conductivity are spaced at short intervals in the flow direction so that good efficiency can be achieved even with materials with high thermal conductivity.

[0024] It can also be advantageous if the material with relatively high thermal conductivity is interrupted into a plurality of segments along the main flow direction. This can be achieved, for example, by thin sheets with slits. The main flow direction can, in particular, extend at least partially parallel to the longitudinal axis of the device, the heat exchanger, and / or the housing.

[0025] The structured part of the lamella can have a cross-sectional narrowing structure or a turbulence-generating structure, by which the fluid flow along the flow direction can be regulated. This allows for targeted regulation / throttling of the flow. This regulation / throttling can be used to improve the heat exchange between the flowing fluid and the channel wall or to induce a phase change in the fluid. The turbulence-generating structure can be designed to be asymmetrical so that it has different efficiencies in the two flow directions. In particular, when constructing a refrigerator, a heat exchanger with an integrated throttle valve can be advantageous because the heat exchanger can simultaneously assume the regulation / throttling function.

[0026] The heat exchanger and the throttle valve can be formed into a common component. This reduces the number of required components and can significantly simplify the system or device. This is particularly advantageous for applications in refrigeration systems.

[0027] According to another aspect, a method for heating or cooling a room using a device (described herein) is proposed, wherein a first, in particular high-temperature fluid flows through a heat exchanger, wherein the thermal energy of the (high-temperature) fluid is transferred to the heat exchanger. Subsequently, a second, in particular low-temperature fluid flows through the heat exchanger, wherein the thermal energy stored in the heat exchanger is transferred to the (low-temperature) fluid. This can reduce the energy required for heating or air conditioning and thus increase the range of purely electric vehicles.

[0028] The proposed device is particularly intended to increase the range of purely electric vehicles, as less battery energy is used for ventilation, cooling, or heating the interior. By utilizing waste heat from components of the vehicle's drive system (such as, in particular, the battery, power electronics, and electric drive motor), energy consumption can be further reduced, which also has a positive impact on range.

[0029] The technical details and / or modes of action given about the device can also be used to describe the features of the method, and vice versa. Specifically, the device can be configured to perform the method, or the method can be implemented using the device proposed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention and its technical environment are explained in more detail below with reference to the accompanying drawings. It should be noted that the drawings illustrate particularly preferred variants of the invention, but are not intended to be limiting. Identical components are provided with the same reference numerals in the drawings. Here, by way of example and diagrammatic representation:

[0031] Figure 1 : buildings having means for transmitting thermal energy; and

[0032] Figure 2 : Cross-sectional view of the heat exchanger of the device. DETAILED DESCRIPTION

[0033] Figure 1 A building 15 is shown in which a device 1 for transferring thermal energy is arranged. Device 1 includes a flow path 4 having a first opening 16 and a second opening 17. First opening 16 is located inside building 15, and second opening 17 is located outside building 15. Flow path 4 extends from a room 13 of building 15 to an area 18 outside building 15. A conveyor device 7 and a heat exchanger 2 are arranged in flow path 4. Heat exchanger 2 extends along a longitudinal axis 14 and has a plurality of flow channels 6. Flow channels 6 extend parallel to longitudinal axis 14 or main flow direction 5. Heat exchanger 2 extends along longitudinal axis 14 over a length 19.

[0034] With the aid of conveying device 7, an air flow 20 can be generated in flow path 4. Conveying device 7 can be operated so that exhaust air from room 13 of building 15 enters flow path 4 via first opening 16, flows through heat exchanger 2, and exits flow path 4 via second opening 17 into external area 18. In this case, first opening 16 serves as an air inlet, and second opening 17 serves as an air outlet. If exhaust air flows through flow path 4 from first opening 16 to second opening 17, heat exchanger 2 can temporarily store the thermal energy of the air flow or exhaust air.

[0035] Subsequently, conveying device 7 can be operated so that fresh air from outside area 18 enters flow path 4 via second opening 17, flows through heat exchanger 2, and exits flow path 4 via first opening 16 into space 13 of building 15. In this case, second opening 17 serves as an air inlet, and first opening 16 serves as an air outlet. If fresh air flows from second opening 17 to first opening 16 via flow path 4, heat exchanger 2 can release temporarily stored thermal energy into the airflow, or fresh air. This preheats the fresh air flowing into building 15.

[0036] Figure 2 The heat exchanger 2 is shown along Figure 1 Cross-sectional view taken along centerline II-II. Heat exchanger 2 is arranged within housing 3. Heat exchanger 2 includes a plurality of structured sheets 9 and smooth sheets 8. Structured sheets 9 and smooth sheets 8 are alternately stacked to form two laminated structures 10. Laminated structures 10 are wound around a rotation axis 11 to form heat exchanger 2, so that sheets 8 and 9 form a plurality of flow channels 6. At least one of sheets 8 and 9 is electrically conductive and (conductively) connected to a voltage source 12.

[0037] List of reference numerals:

[0038] 1 device

[0039] 2 heat exchangers

[0040] 3 Shell

[0041] 4 Flow paths

[0042] 5 Main flow direction

[0043] 6 flow channels

[0044] 7 conveying device

[0045] 8 smooth slices

[0046] 9Structured sheets

[0047] 10-layer structure

[0048] 11 Rotation axis

[0049] 12 Voltage Source

[0050] 13 Space

[0051] 14 Vertical Axis

[0052] 15 buildings

[0053] 16 First Opening

[0054] 17 Second Opening

[0055] 18 External Areas

[0056] 19 Length

[0057] 20 airflow

Claims

1. A device (1) for transferring thermal energy to a fluid, comprising a heat exchanger (2) arranged in a flow path (4) spatially delimited by a housing (3), wherein: The heat exchanger (2) has a plurality of flow channels (6) through which flow can flow along a main flow direction (5), wherein the heat exchanger (2) has a heat storage capacity with which thermal energy can be temporarily stored, wherein a fluid with relatively high energy and a fluid with relatively low energy alternately flow through the heat exchanger (2).

2. The device (1) according to claim 1, characterized in that The flow path (4) has a conveying device (7) or is fluidically connected to a conveying device (7), by means of which a fluid can be conveyed through the flow path (4).

3. The device (1) according to any one of the preceding claims, characterized in that The heat exchanger (2) is composed of a plurality of lamellae (8, 9), wherein the lamellae (8, 9) are designed to be at least partially structured and the lamellae (8, 9) are stacked on top of each other to form a layered structure (10).

4. The device (1) according to claim 3, characterized in that The sheets (8, 9) stacked on top of each other in a stack (10) are wound or coiled around at least one axis of rotation (11).

5. The device (1) according to any one of the preceding claims 3 or 4, characterized in that The sheets (8, 9) are made of metal or plastic.

6. Device (1) according to any one of the preceding claims 3 to 5, characterized in that At least one of the sheets (8, 9) is electrically conductive and is electrically conductively connected to a voltage source (12).

7. Device (1) according to any one of the preceding claims, characterized in that The heat exchanger (2) is made of a composite material, wherein a material with relatively high thermal conductivity and a material with relatively low thermal conductivity are provided.

8. The device (1) according to claim 7, characterized in that The material with relatively high thermal conductivity is interrupted into a plurality of sections along the main throughflow direction (5).

9. Device (1) according to any one of the preceding claims, characterized in that The structured portion of the lamellae (8, 9) has a cross-sectional constriction structure or a turbulence-generating structure, by means of which the flow of the fluid in the flow direction can be regulated.

10. A method for heating, cooling or ventilating a space (13) using a device (1) according to any one of the preceding claims, characterized in that A fluid with a higher temperature flows through the heat exchanger (2), wherein the heat energy of the fluid is transferred to the heat exchanger (2), and then a fluid with a lower temperature flows through the heat exchanger (2), wherein the heat energy stored in the heat exchanger (2) is transferred to the fluid.

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