CN112437865B

CN112437865B - Rotary heat exchanger with tube coils

Info

Publication number: CN112437865B
Application number: CN201980048118.2A
Authority: CN
Inventors: M·G·施罗德
Original assignee: Qingdao Haier Refrigerator Co Ltd; Haier Smart Home Co Ltd; Haier US Appliance Solutions Inc
Current assignee: Qingdao Haier Refrigerator Co Ltd; Haier Smart Home Co Ltd; Haier US Appliance Solutions Inc
Priority date: 2018-07-17
Filing date: 2019-07-16
Publication date: 2022-03-25
Anticipated expiration: 2039-07-16
Also published as: CN112437865A; WO2020015647A1; US20200025456A1

Abstract

A heat exchanger (100) includes a cylindrical stator (110) and a cylindrical rotor (120) separated by a cylindrical gap (130). The cylindrical rotor (120) is configured to rotate about an axis of rotation (X) relative to the cylindrical stator (110). The flat tube (150) is positioned within the cylindrical gap (130) and wound around the cylindrical stator (110). The flat tubes (150) are spaced from the surface of the cylindrical rotor (120) facing the cylindrical gap (130).

Description

Rotary heat exchanger with tube coils

Technical Field

The present subject matter relates generally to heat exchangers.

Background

Some appliances use a sealed refrigeration system to cool portions of the appliance. For example, a refrigerator appliance typically includes a cabinet defining a cooling chamber, which is typically cooled with a sealed refrigeration system. Evaporators incorporating fins, blades or plates conduct heat between the ambient environment and the refrigerant fluid flowing through the sealed refrigeration system.

The efficacy and efficiency of a sealed refrigeration system may depend, at least in part, on the amount of heat that may be exchanged at the evaporator. However, many existing systems have difficulty in consistently exchanging sufficient heat to/from the evaporator. In addition, certain systems (such as systems that utilize multiple static vanes to improve heat exchange) require a large amount of space in order for their corresponding heat exchange features to be effective. In the case of systems using blowers or fans, the rotation of the fans may generate a large amount of undesirable noise. These constraints may limit the availability of the entire device. For example, in the case of a refrigerator appliance, the increase in space required for the heat exchange elements naturally limits the potential size of other parts of the appliance, such as the cooling chamber. The noise generated by one or more fans may limit the area in which a user may want to install the device.

Disclosure of Invention

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In a first example embodiment, a heat exchanger includes a cylindrical stator. The cylindrical rotor is spaced from the cylindrical stator by a cylindrical gap. The cylindrical rotor is configured to rotate about an axis of rotation relative to the cylindrical stator. A flat tube is positioned within the cylindrical gap and wound around the cylindrical stator. The flat tubes are spaced from a surface of the cylindrical rotor facing the cylindrical gap. A heat transfer fluid may flow through the flat tubes. A shear fluid region is defined between the flat tubes and the surface of the cylindrical rotor when the cylindrical gap is filled with a liquid.

In a second example embodiment, an apparatus includes a cabinet defining a cooling chamber. A heat exchanger is positioned within the cabinet. The heat exchanger includes a cylindrical stator. The cylindrical rotor is spaced from the cylindrical stator by a cylindrical gap. The cylindrical rotor is configured to rotate about an axis of rotation relative to the cylindrical stator. A flat tube is positioned within the cylindrical gap and wound around the cylindrical stator. The flat tubes are spaced from a surface of the cylindrical rotor facing the cylindrical gap. A heat transfer fluid may flow through the flat tubes. A shear fluid region is defined between the flat tubes and the surface of the cylindrical rotor when the cylindrical gap is filled with a liquid.

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

Fig. 1 is a front perspective view of a refrigerator apparatus according to an example embodiment of the present disclosure.

Fig. 2 is a schematic diagram of various components of the example refrigerator appliance of fig. 1.

Fig. 3 is a cross-sectional view of a heat exchanger according to an example embodiment of the present disclosure.

Fig. 4 and 5 are schematic diagrams of various components of the example heat exchanger of fig. 3.

FIG. 6 is a cross-sectional view of a heat exchanger according to another example embodiment of the present disclosure.

Detailed Description

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Fig. 1 provides a front view of a representative refrigerator appliance 10 according to an example embodiment of the present disclosure. More specifically, for illustrative purposes, the present disclosure is described in the context of a refrigerator appliance 10 having the configuration shown below and described further below. As used herein, a refrigerator appliance includes appliances such as a refrigerator/freezer combination, side-by-side, bottom-mounted, compact, and any other style or model of refrigerator appliance. Thus, other configurations including multiple and different styles of compartments may be used with the refrigerator appliance 10, it being understood that the configuration shown in FIG. 1 is provided as an example only.

The refrigerator appliance 10 includes a fresh food storage compartment 12 and a freezer storage compartment 14. In this embodiment, the freezer compartment 14 and the fresh food compartment 12 are arranged side-by-side within the outer shell 16 and are defined by inner liners 18 and 20 therein. The space between the shell 16 and the liners 18, 20 and between the liners 18, 20 can be filled with foam-in-place insulation. The outer housing 16 is typically formed by folding a sheet of suitable material, such as pre-coated steel, into an inverted U-shape to form the top and side walls of the housing 16. The bottom wall of the housing 16 is typically formed separately and attached to the housing side walls and to a bottom frame that provides support for the refrigerator appliance 10. The inner liners 18 and 20 are molded of a suitable plastic material to form the freezer compartment 14 and fresh food compartment 12, respectively. Alternatively, the liners 18, 20 may be formed by bending and welding a sheet of a suitable metal, such as steel.

A spacer 22 extends between the shell front flange and the outer front edge of the liners 18, 20. The release strip 22 is formed of a suitable elastomeric material, such as an extruded propylene-butadiene-styrene based material (commonly referred to as ABS). The insulation in the space between the liners 18, 20 is covered by another suitable strip of resilient material, also commonly referred to as a mullion 24. In one embodiment, mullion 24 is formed of extruded ABS material. The spacer 22 and mullion 24 form the front surface and extend completely around the inner peripheral edge of the shell 16 and vertically between the liners 18, 20. The mullions 24, insulation between the cells, and the dividing walls of the lining separating the cells are sometimes collectively referred to herein as central mullion walls 26. In addition, the refrigerator appliance 10 includes a shelf 28 and a slide-out storage drawer 30, sometimes referred to as a storage tray, which are typically disposed in the fresh food compartment 12 to support items stored therein.

The refrigerator appliance 10 may be operated by one or more controllers 11 or other processing devices according to programming or user preferences via manipulation of a mounted (e.g., mounted in an upper region of the fresh food storage compartment 12 and connected to the controller 11) control interface 32. The controller 11 may include one or more memory devices (e.g., non-transportable memory) and one or more microprocessors, such as a general purpose or special purpose microprocessor operable to execute programming instructions or microcontrol code associated with the operation of the refrigerator appliance 10. The memory may represent a random access memory such as a DRAM or a read only memory such as a ROM or FLASH. In one embodiment, the processor executes programming instructions stored in the memory. The memory may be a separate component from the processor or may be an on-board component included within the processor. The controller 11 may include one or more proportional-integral ("PI") controllers programmed, equipped, or configured to operate the refrigerator appliance according to various control methods. Thus, as used herein, "controller" includes both singular and plural forms.

The controller 11 may be located at various locations throughout the refrigerator appliance 10. In the illustrated embodiment, the controller 11 may be located behind the interface panel 32 or the

door

42 or 44, for example. Input/output ("I/O") signals may be routed between the control system and various operating components of the refrigerator appliance 10 along a wiring harness, which may be routed through the back, side, or mullion 26, for example. Generally, through the user interface panel 32, a user can select various operating features and modes and monitor the operation of the refrigerator appliance 10. In one embodiment, the user interface panel 32 may represent a general purpose I/O ("GPIO") device or function block. In one embodiment, the user interface panel 32 may include input components such as one or more of a variety of electrical, mechanical, or electromechanical input devices including rotary dials, buttons, and touch pads. The user interface panel 32 may include a display component, such as a digital or analog display device designed to provide operational feedback to a user. The user interface panel 32 may communicate with the controller 11 via one or more signal lines or a shared communication bus.

In some embodiments, one or more temperature sensors are provided to measure the temperature in the fresh food compartment 12 and the temperature in the freezer compartment 14. For example, the first temperature sensor 52 may be disposed in the fresh food compartment 12 and may measure the temperature in the fresh food compartment 12. The second temperature sensor 54 may be provided in the freezing compartment 14, and may measure the temperature in the freezing compartment 14. Such temperature information may be provided (e.g., to the controller 11 for operating the refrigerator 10). These temperature measurements may be made intermittently or continuously during operation of the device or execution of the control system.

Alternatively, a rack 34 and a wire basket 36 may be provided in the freezer compartment 14. Additionally or alternatively, an ice maker 38 may be provided in the freezer compartment 14. A freezer door 42 and a fresh food door 44 close the access to the freezer compartment 14 and the fresh food compartment 12, respectively. Each

door

42, 44 is mounted for rotation about its outer vertical edge between an open position as shown in fig. 1 and a closed position (not shown) closing the associated storage compartment. In alternative embodiments, one or both of the

doors

42, 44 may be slidable or otherwise movable between open and closed positions. The freezer door 42 includes a plurality of holding shelves 46 and the fresh food door 44 includes a plurality of holding shelves 48.

Referring now to fig. 2, the refrigerator appliance 10 may include a refrigeration system 200. Generally, the refrigeration system 200 is charged with a refrigerant that flows through various components and helps cool the fresh food compartment 12 and the freezer compartment 14. The refrigeration system 200 may be charged or charged with any suitable refrigerant. For example, the refrigeration system 200 may be charged with a flammable refrigerant, such as R441A, R600a, isobutylene, isobutane, and the like.

The refrigeration system 200 includes a compressor 202 for compressing a refrigerant, thereby increasing the temperature and pressure of the refrigerant. Compressor 202 may be, for example, a variable speed compressor such that the speed of compressor 202 may be varied between zero percent (0%) and one hundred percent (100%) by controller 11. The refrigeration system 200 may further include a condenser 204, which may be disposed downstream of the compressor 202 in a flow direction of the refrigerant. Thus, the condenser 204 may receive refrigerant from the compressor 202 and may condense the refrigerant by, for example, reducing the temperature of the refrigerant flowing therethrough as a result of heat exchange with ambient air).

The refrigeration system 200 further includes an evaporator 210 disposed downstream of the condenser 204. Additionally, an expansion device 208 may be utilized to expand the refrigerant, thereby further reducing the pressure of the refrigerant, exiting the condenser 204 before flowing to the evaporator 210. The evaporator 210 generally transfers heat from the ambient air passing through the evaporator 210 to the refrigerant flowing through the evaporator 210, thereby cooling the air and causing the refrigerant to evaporate. As shown, an evaporator fan 212 may be used to force air through the evaporator 210. In this way, cooled air is generated and supplied to the

fresh food compartments

12, 14 of the refrigerator appliance 10. In some embodiments, the evaporator fan 212 may be a variable speed evaporator fan such that the speed of the fan 212 may be controlled or set anywhere between and including, for example, zero percent (0%) and one hundred percent (100%). The speed of the evaporator fan 212 may be determined by the controller 11 and communicated to the evaporator fan 212.

Turning now to fig. 3-5, a heat exchanger 100 according to an example embodiment of the present disclosure is discussed in more detail below. The heat exchanger 100 may be used in a refrigerator appliance 10, for example, as a condenser 204 and/or an evaporator 210. Accordingly, the heat exchanger 100 is described in more detail below in the context of the refrigerator appliance 10. However, it should be appreciated that in alternative example embodiments, the heat exchanger 100 may be used in or with any suitable device. For example, the heat exchanger 100 may be used in a heat pump water heater, a heat pump dryer, an HVAC unit, and the like. The heat exchanger 100 may define an axial direction a and a radial direction R that are perpendicular to each other.

As shown in fig. 3, the heat exchanger 100 includes a cylindrical stator 110 and a cylindrical rotor 120. The cylindrical stator 110 and the cylindrical rotor 120 may collectively form the hub 102 of the heat exchanger 100. The cylindrical rotor 120 is spaced from the cylindrical stator 110 by a cylindrical gap 130. Thus, for example, the cylindrical rotor 120 may not contact the cylindrical stator 110 at the cylindrical gap 130. The cylindrical rotor 120 is configured to rotate about a rotation axis X relative to the cylindrical stator 110. The rotation axis X may be parallel to the axial direction a and perpendicular to the radial direction R. To rotate the cylindrical rotor 120, the heat exchanger 100 may include a motor 140. The motor 140 is coupled to the cylindrical rotor 120 such that the motor 140 is operable to rotate the cylindrical rotor 120 about the rotational axis X.

The motor 140 may be a variable speed motor. Thus, for example, the rotational speed of the cylindrical rotor 120 about the rotational axis X may be adjusted by varying the speed of the motor 140. The controller 11 may be in operative communication with the motor 140, and the controller 11 may be operable to adjust the speed of the motor 140. The speed of the motor 140 may be controlled or set anywhere between and including, for example, zero percent (0%) and one hundred percent (100%). As a particular example, the motor 140 may be operable to adjust the rotational speed of the cylindrical rotor 120 about the rotational axis X to any suitable speed of no less than two hundred and fifty revolutions per minute (250RPM) and no greater than two thousand and five hundred revolutions per minute (2500 RPM).

In fig. 3, a cylindrical stator 110 is positioned within a cylindrical rotor 120. Specifically, the cylindrical stator 110 is positioned inside the cylindrical rotor 120, and is positioned coaxially with the cylindrical rotor 120. It should be appreciated that in alternative example embodiments, the relative positions of the cylindrical stator 110 and the cylindrical rotor 120 may be reversed. Thus, in alternative example embodiments, for example, the cylindrical rotor 120 may be positioned within the cylindrical stator 110.

In fig. 3, the motor 140 is also positioned within the cylindrical stator 110. For example, the motor 140 may be positioned within the interior volume 114 of the cylindrical stator 110. The internal volume 114 may be positioned opposite the cylindrical gap 130 in the radial direction R around the cylindrical stator 110. The shaft 142 of the motor 140 may extend from the interior volume 114 through the end wall 116 of the cylindrical stator 110, for example, in the axial direction a. The cylindrical rotor 120 is coupled to a shaft 142 of the motor 140. Thus, the motor 140 may be operable to rotate the cylindrical rotor 120 about the rotational axis X from within the cylindrical stator 110. An O-ring 118 or other suitable seal may extend between the shaft 142 of the motor 140 and the end wall 116 of the cylindrical stator 110. The O-ring 118 may prevent liquid from flowing into the interior volume 114 via the interface between the shaft 142 of the motor 140 and the end wall 116 of the cylindrical stator 110. In alternative example embodiments, the motor 140 may be positioned outside of the cylindrical stator 110, and the cylindrical rotor 120 may be driven by the motor 140 through a gear or belt/pulley.

The flat tube 150 is positioned within the cylindrical gap 130, and the flat tube 150 is wound around the cylindrical stator 110, for example, such that the flat tube 150 is wound around the cylindrical stator 110. Accordingly, during operation of the motor 140, the cylindrical rotor 120 may rotate relative to the flat tubes 150. The flat tubes 150 are also spaced apart from the surface 122 of the cylindrical rotor 120, e.g., in the radial direction R. The surface 122 of the cylindrical rotor 120 faces the cylindrical gap 130. In fig. 3, the surface 122 of the cylindrical rotor 120 is the inner surface of the cylindrical rotor 120, and the flat tubes 150 are wound around the outer surface 112 of the cylindrical stator 110. As shown in fig. 3, the flat tubes 150 may be wound in one or more layers onto the outer surface 112 of the cylindrical stator 110. A heat transfer fluid, such as a refrigerant, may flow through the flat tubes 150.

The cylindrical gap 130 may be filled with a liquid such as water, propylene glycol, or the like, and the liquid may promote heat transfer in the radial direction R within the cylindrical gap 130 between the cylindrical rotor 120 and the flat tubes 150. For example, the liquid in the cylindrical gap 130 may facilitate conductive heat transfer between the cylindrical rotor 120 and the flat tubes 150, e.g., relative to the cylindrical gap 130 filled with a gas such as air. Accordingly, the liquid in the cylindrical gap 130 may contact both the cylindrical rotator 120 and the flat tubes 150 within the cylindrical gap 130, and the liquid may correspond to the heat transfer fluid between the cylindrical rotator 120 and the flat tubes 150 within the cylindrical gap 130.

In addition, a shear fluid zone 160 is defined between the flat tubes 150 and the surface 122 of the cylindrical rotor 120. Thus, shear fluid region 160 may correspond to, for example, a portion of cylindrical gap 130 positioned in radial direction R between surface 122 of cylindrical rotor 120 and flat tubes 150. The liquid within the shear liquid region 160 may shear during rotation of the cylindrical rotor 120 relative to the cylindrical stator 110, and the shear of the liquid may facilitate convective heat transfer between the cylindrical rotor 120 and the flat tubes 150 via the liquid.

By positioning the flat tubes 150 within the cylindrical gap 130, the heat exchanger 100 can be produced in a more cost-effective manner relative to known heat exchangers that require complex flow circuits. In addition, the size of the heat exchanger 100 may be reduced relative to known heat exchangers. For example, the size of the heat exchanger 100 may be about half of known heat exchangers that have similar heat transfer characteristics and require, for example, fans, shrouds, ridge fins, and the like.

Convective heat transfer within the cylindrical gap 130 increases with shear rate. Thus, varying the rotational speed of the cylindrical rotor 120 about the axis of rotation X (e.g., by varying the speed of the motor 140 in the manner described above) can likewise vary the convective heat transfer in the radial direction R within the cylindrical gap 130 between the cylindrical rotor 120 and the flat tubes 150. In particular, increasing the rotational speed of the cylindrical rotor 120 about the rotational axis X may increase convective heat transfer in the radial direction R within the cylindrical gaps 130 between the cylindrical rotor 120 and the flat tubes 150. Conversely, reducing the rotational speed of the cylindrical rotor 120 about the rotational axis X can reduce convective heat transfer in the radial direction R within the cylindrical gaps 130 between the cylindrical rotor 120 and the flat tubes 150.

Turning to fig. 4, flat tube 150 may have a flat or planar surface 152. Thus, for example, the flat tube 150 can have a non-circular cross-section. In fig. 4, the flat tube 150 has a square cross section. In alternative example embodiments, the flat tubes 150 may have a stadium-shaped cross section, a rectangular cross section, or the like. By way of example, the flat tube 150 may be formed by rolling a round metal tube to form the flat surface 152. Accordingly, the flat tube 150 may be a rolled metal tube.

The flat surfaces 152 of the flat tubes 150 can face the surface 122 of the cylindrical rotor 120 through the shear fluid zone 160. Thus, for example, the flat surfaces 152 of the flat tubes 150 can correspond to the static shear surfaces of the shear fluid zone 160, and the surface 122 of the cylindrical rotor 120 can correspond to the dynamic shear surfaces of the shear fluid zone 160. The flat surfaces 152 of the flat tubes 150 may be oriented parallel to the surface 122 of the cylindrical rotor 120 through the shear fluid zone 160.

A thickness T of shear fluid region 160 may be defined in radial direction R between flat surfaces 152 of flat tubes 150 and surface 122 of cylindrical rotor 120. In certain exemplary embodiments, the thickness T of shear fluid zone 160 may be no less than about one hundredth of an inch (0.01 inch) and no greater than about one tenth of an inch (0.1 inch). As used herein, the term "about" means within ten percent of the thickness when used in the context of that thickness. By utilizing flat tubes 150, the thickness T of the shear fluid zone 160 may be more consistent or uniform relative to a round tube. In addition, the heat exchanger 100 may be formed to have a size of reduced thickness T of the shear fluid region 160 relative to using a circular tube by using the flat tube 150.

The flat tubes 150 may provide a single flow path for the heat transfer fluid. However, in certain example embodiments, the heat exchanger 100 includes a plurality of flat tubes 150. For example, as shown in fig. 4, the heat exchanger 100 may include a first flat tube 152 and a second flat tube 154. First flat tube 152 and second flat tube 154 are each positioned within cylindrical gap 130 and wound around cylindrical stator 110. First flat tube 152 and second flat tube 154 may depend in parallel within refrigeration system 200 such that first flat tube 152 and second flat tube 154 each define a respective flow path for the heat transfer fluid through heat exchanger 100.

Referring to fig. 3 and 5, the heat exchanger 100 may include a fan 170. The fan 170 may include a plurality of spaced apart planar fins 172. Spaced apart planar fins 172 extend outwardly from the cylindrical rotor 120, for example, in the radial direction R. The cylindrical rotor 120 may be formed of or have a suitable thermally conductive material. For example, the cylindrical rotor 120 may be formed from one or more conductive materials, such as aluminum, copper, or tin, and alloys thereof. Each planar fin 172 is in conductive thermal communication with the cylindrical rotor 120. For example, the planar fins 172 may directly contact the cylindrical rotor 120. In certain example embodiments, the spaced apart planar fins 172 are separably attached (e.g., in direct or indirect contact therewith) to the cylindrical rotor 120 (e.g., as discrete removable disks). The spaced apart planar fins 172 may also be formed of the same or different conductive material as the material of the cylindrical rotor 120. For example, the spaced apart planar fins 172 may be formed of stainless steel, aluminum, copper, or tin, and alloys thereof.

The spaced apart planar fins 172 define one or more axial air intake passages 174. The axial air intake passage 174 may extend through one or more of the spaced apart planar fins 172, e.g., parallel to the axis of rotation X and/or in the axial direction a. Each of the axial inlet passages 174 may be positioned at a common radial distance from the axis of rotation X.

The spaced apart planar fins 172 are mounted to the cylindrical rotor 120, for example, such that the spaced apart planar fins 172 rotate with the cylindrical rotor 120 about the rotational axis X. As the spaced apart planar fins 172 rotate, the fan 170 operates in a manner similar to a so-called "tesla fan". Turning to fig. 5, as the spaced apart planar fins 172 rotate about the axis of rotation X, airflow (shown by arrow AF) may be drawn into the axial inlet passage 174 in the axial direction a. The airflow AF may flow from the opposite axial end spaced apart planar fins 172 into the axial air intake passage 174. Within the spaced apart planar fins 172, the airflow AF passes from the axial inlet passage 174 to one or more outlet passages defined between adjacent spaced apart planar fins 172. The exhaust passages may correspond to axial gaps between adjacent spaced apart planar fins 172.

The airflow AF is directed outwardly from the exhaust passage in the radial direction R between the spaced apart planar fins 172 prior to being discharged from the heat exchanger 100. Advantageously, the heat exchanger 100 may facilitate heat exchange between the spaced apart planar fins 172 and the air flow AF without generating noise associated with, for example, an axial blower fan. Thus, for example, when the heat exchanger 100 is used as a condenser 204, the spaced apart planar fins 172 may reject heat to the airflow AF during operation of the heat exchanger 100. Alternatively, for example, when the heat exchanger 100 is used as the evaporator 210, the airflow AF may reject heat to the spaced apart planar fins 172 during operation of the heat exchanger 100.

As the spaced apart planar fins 172 rotate, viscous forces add energy to the airflow AF between the spaced apart planar fins 172. The boundary layers on the spaced apart planar fins 172 may drive the airflow AF outward in the radial direction R. The spacing between adjacent spaced apart planar fins 172 in the axial direction a may be selected to promote driving the airflow AF outwardly in the radial direction R between the spaced apart planar fins 172. For example, each spaced planar fin 172 may be spaced from an adjacent spaced planar fin 172 by no more than about twenty-five microns (25 μm) in the axial direction a. In certain example embodiments, such spacing may allow the fan 170 to operate in the manner described above.

As shown in fig. 6, the cylindrical stator 110 may include fins or corrugations 124 that project outward in the radial direction R. The flat tubes 150 may be positioned on the distal ends of the corrugations 124. The spaces or gaps between adjacent corrugations 124 may provide a flow path for liquid, for example, in the axial direction a between the cylindrical stator 110 and the flat tubes 150. Thus, liquid in the cylindrical gap 130 may flow in the space between adjacent corrugations 124, and the liquid between adjacent corrugations 124 may increase convective heat transfer in the radial direction R in the cylindrical gap 130 between the cylindrical rotor 120 and the flat tubes 150 relative to the cylindrical stator 110 without corrugations 124.

The cylindrical rotor 120 may include fins or corrugations 119 that project outward in the radial direction R. A planar fin 172 may be mounted at the distal end of the corrugations 119. The air inlet passage 174 may be formed by a space or gap between the corrugations 119 and the inner edge of the planar fin 172. The corrugations 119 may increase the surface area directly exposed to ambient air relative to the example shown in fig. 3. Vortices may also form within the corrugations 119, thereby increasing heat transfer.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A heat exchanger, comprising:

a cylindrical stator;

a cylindrical rotor spaced from the cylindrical stator by a cylindrical gap, the cylindrical rotor configured to rotate relative to the cylindrical stator about an axis of rotation;

a flat tube positioned within the cylindrical gap and wound around the cylindrical stator, the flat tube being spaced from a surface of the cylindrical rotor facing the cylindrical gap, a heat transfer fluid being flowable through the flat tube,

wherein a shear fluid region is defined between the flat tube and the surface of the cylindrical rotor when the cylindrical gap is filled with a liquid.

2. The heat exchanger of claim 1, wherein the cylindrical stator is positioned within the cylindrical rotor.

3. The heat exchanger of claim 2, wherein the cylindrical stator is positioned coaxially with the cylindrical rotor.

4. The heat exchanger of claim 2, further comprising a motor positioned within the cylindrical stator, the motor coupled to the cylindrical rotor such that the motor is operable to rotate the cylindrical rotor relative to the cylindrical stator.

5. The heat exchanger of claim 4, wherein a shaft of the motor extends in an axial direction through an end wall of the cylindrical stator, the cylindrical rotor being coupled to the shaft of the motor.

6. The heat exchanger of claim 1, further comprising a plurality of spaced apart planar fins extending in a radial direction from the cylindrical rotor, the plurality of spaced apart planar fins defining an axial inlet passage extending through one or more of the plurality of spaced apart planar fins parallel to the axis of rotation.

7. The heat exchanger of claim 6, wherein the axial inlet passage is one of a plurality of axial inlet passages, and each of the plurality of axial inlet passages extends through one or more of the plurality of spaced apart planar fins parallel to the axis of rotation.

8. The heat exchanger of claim 7, wherein each of the plurality of axial inlet passages is positioned at a common radial distance from the axis of rotation.

9. The heat exchanger of claim 6, wherein each of the plurality of spaced apart planar fins is spaced from an adjacent planar fin of the plurality of spaced apart planar fins by an axial gap that is no greater than twenty-five microns.

10. The heat exchanger according to claim 1, wherein the flat tube is one of a plurality of flat tubes, each of the plurality of flat tubes positioned within the cylindrical gap and wound around the cylindrical stator.

11. The heat exchanger according to claim 10, wherein the plurality of flat tubes define a plurality of parallel flow paths for the heat transfer fluid.

12. The heat exchanger of claim 1, wherein the shear fluid zone has a thickness in a radial direction, the thickness of the shear fluid zone being no less than one hundredth of an inch and no greater than one tenth of an inch.

13. The heat exchanger according to claim 1, wherein the flat tubes have flat surfaces that face the surface of the cylindrical rotor through the shear liquid region.

14. The heat exchanger according to claim 1, wherein the flat tubes are rolled metal tubes.

15. An apparatus, comprising:

a cabinet defining a cooling chamber;

a heat exchanger positioned within the cabinet, the heat exchanger including

A cylindrical stator;

16. The apparatus of claim 15, wherein the cylindrical stator is positioned within the cylindrical rotor and the cylindrical stator is positioned coaxially with the cylindrical rotor.

17. The apparatus of claim 16, wherein the heat exchanger further includes a motor positioned within the cylindrical stator, the motor coupled to the cylindrical rotor such that the motor is operable to rotate the cylindrical rotor relative to the cylindrical stator, a shaft of the motor extending in an axial direction through an end wall of the cylindrical stator, the cylindrical rotor coupled to the shaft of the motor.

18. The apparatus of claim 15, wherein the heat exchanger further includes a plurality of spaced apart planar fins extending in a radial direction from the cylindrical rotor, the plurality of spaced apart planar fins defining an axial inlet channel extending through one or more of the plurality of spaced apart planar fins parallel to the axis of rotation, each of the plurality of spaced apart planar fins being spaced from an adjacent planar fin of the plurality of spaced apart planar fins by an axial gap, the axial gap being no greater than twenty-five microns.

19. The apparatus of claim 15, wherein said shear fluid zone has a thickness in the radial direction that is not less than one hundredth of an inch and not more than one tenth of an inch.

20. The apparatus of claim 15 wherein the flat tube has a flat surface facing the surface of the cylindrical rotor over the shear liquid region.