Dynamic heat exchanger

Abstract

A rotary heat exchanger includes a housing defining an interior space and heat transfer structure in the interior space. The heat transfer structure includes a plurality of concentric discs disposed in spaced relation to define passageways between the discs. The discs are mounted for rotation within the housing. Partition structure divides the interior space into first and second chambers. When heat transfer structure is rotated and first and second fluids are introduced into the associated chambers and between the passageways, with the first fluid having a temperature greater than a temperature of the second fluid, the discs are rapidly heated thereby removing heat from the first fluid and heating the second fluid.

Description

FIELD OF THE INVENTION

The invention relates to fluid heat exchangers and, more particularly, to regenerative heat exchangers that rotate and have two separated chambers through which respective heat supplying and heat receiving fluids circulate.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,491,171 discloses a regenerative type heat exchanger having a cylindrical roller that rotates. Two media flows are separated by a divider wall. A first media flow supplies heat and the heats the wall of the roller as the media flow passes through the wall. Since the roller is rotating, the second media flow flows through the previous heated wall and becomes heated. Thus, the heat is removed from the first media flow and heat is supplied to the second media flow. The roller is comprised of pourable or flowable materials in spherical or granular form.

Other conventional regenerators employ a large foam disc impregnated with water that rotates between the two media flows. Although these materials have high heat capacity, they are not suitable for quickly accumulating heat from the first flow medium and then quickly transferring the heat to the second flow medium.

Thus, there is a need to provide a dynamic heat transfer device that accumulates quickly from one media flow and that quickly transfers heat to the other media flow.

SUMMARY OF INVENTION

An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by providing a rotary heat exchanger for heat exchange between at least two fluids. The rotary heat exchanger includes a housing defining an interior space. Heat transfer structure is provided in the interior space of the housing. The heat transfer structure is in the form of a plurality of concentric, plate-shaped discs disposed in spaced relation to define passageways between the discs. The discs are mounted for rotation within the housing. A first inlet is provided in the housing for introducing a first fluid into the interior space of the housing, A second inlet is provided in the housing for introducing a second fluid into the interior space of the housing. Partition structure divides the interior space into first and second chambers with the first inlet communicating with the first chamber and the second inlet communicating with the second chamber. A first outlet is provided in the housing for removal of the first fluid from the first chamber after heat exchange with the heat transfer structure, and a second outlet is provided in the housing for removal of the second fluid from the second chamber after heat exchange with the heat transfer structure. When heat transfer structure is rotated and the first and second fluids are introduced into their associated chambers and between the passageways, with the first fluid having a temperature greater than a temperature of the second fluid, the discs are rapidly heated thereby removing heat from the first fluid and heating the second fluid.

In accordance with another aspect of the invention, a rotary heat exchanger is provided for heat exchange between at least two fluids. The rotary heat exchanger includes a housing defining an interior space. Means for transferring heat is provided in the interior space of the housing. The means for transferring heat includes a plurality of members disposed in spaced relation and mounted on a shaft for simultaneous rotation upon rotation of the shaft. A first inlet is provided in the housing for introducing a first fluid into the interior space of the housing and a second inlet is provided in the housing for introducing a second fluid into the interior space of the housing. Means for dividing the interior space into first and second chambers is provided, with the first inlet communicating with the first chamber and the second inlet communicating with the second chamber. A first outlet is provided in the housing for removal of the first fluid from the first chamber after heat exchange with the heat transfer structure, and a second outlet is provided in the housing for removal of the second fluid from the second chamber after heat exchange with the heat transfer structure. When the members are rotated and the first and second fluids are introduced into the associated chambers and spaces between the members, with the first fluid having a temperature greater than a temperature of the second fluid, the members are rapidly heated thereby removing heat from the first fluid and heating the second fluid.

Other objects, features, functionality and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawing, in which:

FIG. 1 is top view, partially in section, of a dynamic heat exchanger provided in accordance with the principles of an embodiment of the present invention.

FIG. 2 is a side view of the dynamic heat exchanger of FIG. 1 shown with a portion thereof removed so that discs are visible, and showing a controller and motor.

FIG. 3 is an enlarged view of a disc of the heat exchanger of FIG. 2.

FIG. 4 is a side view of a spacer disposed between a pair of discs of the heat exchanger of FIG. 2, shown with flocking associated with the spacer.

FIG. 5 is a view of the portion encircled at 5 in FIG. 4.

FIG. 6 is a top view of a spacer of the heat exchanger of FIG. 1 shown with temperature sensors associated therewith.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENT

With reference to FIGS. 1 and 2, a rotary heat exchanger for heat exchange between at least two fluids is shown, generally indicated at 10, in accordance with an embodiment of the invention. The rotary heat exchanger 10 includes a housing 12 defining an interior space 14. Heat transfer structure, generally indicated at 15, is provided in the interior space 14 and in the embodiment is in the form of a plurality of concentric, plate-shaped members or discs 16 disposed in spaced relation to define passageways 18 (FIG. 2) between the discs. Each disc 16 is mounted for rotation within the housing. More particularly, with reference to FIG. 2, each disc 16 is coupled with a common shaft 20 that is rotated by a motor 22. Each disc 16 is coupled at central portion thereof to the shaft 20. The shaft 20 can be part of the motor 22 or coupled with a shaft of the motor 22. The discs 16 can be a structure made from a single material having high thermal conductivity (e.g., copper). However, in the embodiment of FIG. 3, (note that thickness of the disc is not to scale) each disc 16 has a base 24 of a material of a certain thermal conductivity, and at least one layer 26 of material on the base 24 with a thermal conductivity substantially greater than the certain conductivity of the base 24. In the embodiment, the base 24 is preferably composed of a polycarbonate plastic (as in a conventional compact disc), or other materials having low thermal conductivity such as ceramic, steel, etc. Opposing surfaces of the base 24 are covered with a thin layer 26 of a heat conductive metal such as, for example, silver, copper, or gold. It is desirable to provide the base 24 as thin as a possible yet mechanically sound so that a plurality of discs 16 can be provided in a compact space. For example, discs 16 with a 5″ diameter and an overall thickness of about 0.05″ can be used. The more discs used, the more surface area is provided for heat transfer.

With reference to FIG. 1, a first inlet 28 is provided in the housing 12 for introducing a first fluid F1 into the interior space 14 of the housing 12. A second inlet 30 is provided in the housing 12 for introducing a second fluid F2 into the interior space 14 of the housing 12. The inlets 28 and 30 are on opposite ends of the housing 12 so that the first and second fluids flow in opposite directions and preferably counter to the rotation of the discs 16. Thus, the exposure of the discs to the fluid flows F1, F2 is maximized and the heat transfer rate benefits from the temperature gradient profile of the fluids F1, F2 and the discs 16. In the embodiment, the fluids F1 and F2 are air, but can be other fluids.

In the embodiment, the first fluid F1 is at a temperature of about 140° F. and the second fluid F2 is at a temperature of about 40° F. Of course, other fluid temperatures can be uses so long as there is a temperature difference between the fluids F1, and F2. Partition structure 32 divides the interior space 14 into first and second chambers 34, 36, with the first inlet 28 communicating with the first chamber 24 and the second inlet 30 communicating with the second chamber 36. In the embodiment, the partition structure 32 comprises a plurality of spacers 37 disposed about the shaft 20 and fixed to the housing 12 to maintain spacing between adjacent discs 16 and to divide the interior space 14 into the first and second chambers, 34, 36. Spacers 37′ can also be associated with the housing 12 near the periphery of the discs 16. The rotating discs 16 pass the spacers 37, 37′ with very little clearance so that fluids F1, F2 passing through the chambers 34, 36 will have very little exchange.

A first outlet 38 is provided in the housing 12 for removal of the first fluid F1 from the first chamber 34 after heat exchange with the heat transfer structure 15. A second outlet 40 is provided in the housing for removal of the second fluid F2 from the second chamber 36 after heat exchange with the heat transfer structure 15.

Thus, when the heat transfer structure 15 is rotated in direction A and the first and second fluids F1, F2 are introduced into the interior space 14 and passageways 18, layers 26 of material on the discs 16 are rapidly heated thereby removing heat from the first fluid F1 and heating the second fluid F2. Hence, for example, the second fluid F2 exits the outlet 36 at a temperature of about 130° F. and the first fluid F1 exits the outlet 38 at a temperature of about 45° F.

The rate that heat can be picked up from the flow of fluid F1 and delivered to the other flow of fluid F2 is increased due to the provision of the thin-film coating or layers 26 on the discs 16. Thus use of the layers 26 permits higher disc RPM and high heat transfer in a small package.

The heat transfer can be further enhanced by inducing turbulence to the flow of fluids F1, F2 to disrupt the formation of boundary layers. This is particularly advantageous if the fluid is air. The roughness and spacing of the discs 16 can be adjusted to ensure air turbulence. Roughness could be achieved, for example, by providing concentric ridges 42 and grooves 44 (FIG. 3) in the layers 26 of the discs 16. In addition, employing soft, compliant spacers 37 that separate the discs 16 and air flow chambers 34, 36, the ridges have very little effect on air leakage. If fluid leakage past the spacers 37 is an issue, as shown in FIGS. 4 and 5, flocking 39 or flaps, as seal structure, can be associated with at least portions of the spacers 37 to contact the rotating discs 16 to reduce the fluid leakage, without requiring tight tolerances. Flocking 39 or other seal structures can also be provided on spacers 37′.

Since the high thermal conductive surface (layer 26) is on a low conductive base 24, the heat exchange rate is enhanced. In addition, the speed of rotation of the discs 16 could be automatically adjusted to maximize heat exchange. For example, with reference FIG. 6, at least one sensor 46 is mounted to the housing 12 or spacer 37 sing 12 in the internal space 14 to determine the rate of heat transfer of the heat exchanger 10. The sensor 46 can be a thermistor or other sensor that senses temperature or a change in temperature. In the embodiment, four sensors 46 are provided. A signal 49 from the sensor(s) 46 is received by a controller 48, preferably having a processor 50. The controller 48 monitors the rate of heat transfer by monitoring the temperature signals over time. If it is determined that the rate of heat transfer needs to be adjusted, the controller 48 controls the speed of the motor 22 accordingly.

Since total separation of the fluids F1 and F2 need not be 100%, the rotary heat exchanger 10 can be small, compact, simple and very efficient.

The heat exchanger can be used to provide fresh air to a house with little heat loss, to ventilate a crawl space or basement to remove moisture or Radon gas, to salvage heat from a clothes dryer, to heat or cool air for breathing by a human, etc.

The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.

Claims

1. A rotary heat exchanger for heat exchange between at least two fluids, the rotary heat exchanger comprising: a housing defining an interior space,heat transfer structure in the interior space of the housing, the heat transfer structure being in the form of a plurality of concentric, plate-shaped discs disposed in spaced relation to define passageways between the discs, the discs being mounted for rotation within the housing,a first inlet in the housing for introducing a first fluid into the interior space of the housing,a second inlet in the housing for introducing a second fluid into the interior space of the housing,partition structure dividing the interior space into first and second chambers with the first inlet communicating with the first chamber and the second inlet communicating with the second chamber,a first outlet in the housing for removal of the first fluid from the first chamber after heat exchange with the heat transfer structure, anda second outlet in the housing for removal of the second fluid from the second chamber after heat exchange with the heat transfer structure,wherein when the heat transfer structure is rotated and the first and second fluids are introduced into their associated chambers and between the passageways, with the first fluid having a temperature greater than a temperature of the second fluid, the discs are rapidly heated thereby removing heat from the first fluid and heating the second fluid.

2. The rotary heat exchanger of claim 1, wherein each disc has a base with a material of a certain thermal conductivity, and at least a layer of material on the base with a thermal conductivity substantially greater than the certain conductivity.

3. The rotary heat exchanger of claim 1, wherein the partition structure comprises a plurality of spacers that space the discs a distance apart.

4. The rotary heat exchanger of claim 2, wherein the base is of composed of polycarbonate plastic and the layer of material on the base is a metal.

5. The rotary heat exchanger of claim 2, wherein the base is of composed of plastic material and the layer of material on the base is a metal.

6. The rotary heat exchanger of claim 5, wherein the metal is one of silver, copper or gold.

7. The rotary heat exchanger of claim 5, wherein the metal is one of silver, copper or gold.

8. The rotary heat exchanger of claim 2, wherein each base has opposing surfaces and said layer of material is on each opposing surface.

9. The rotary heat exchanger of claim 1, wherein the first and second inlets are at opposite ends of the housing so that the first and second fluids can flow in opposite directions and counter to the rotation of the discs.

10. The rotary heat exchanger of claim 2, wherein the layer of material has a plurality of ridges and grooves therein to promote turbulent flow of the fluids over the discs.

11. The rotary heat exchanger of claim 1, wherein each disc is coupled with a common shaft for rotation therewith.

12. The rotary heat exchanger of claim 3, further including seal structure associated with the spacers so as to provide a seal with respect to the discs.

13. The rotary heat exchanger of claim 1, in combination with a motor, a controller and at least one sensor, the motor being constructed and arranged to rotate the heat transfer structure, the sensor being constructed and arranged to sense temperature changes within the heat exchanger, the sensor being constructed and arranged to send a signal to the controller such that the controller can control the speed of the motor to control a heat transfer rate of the heat exchanger.

14. A rotary heat exchanger for heat exchange between at least two fluids, the rotary heat exchanger comprising: a housing defining an interior space,means for transferring heat in the interior space of the housing, the means for transferring heat including a plurality of members disposed in spaced relation and mounted on a shaft for simultaneous rotation upon rotation of the shaft,a first inlet in the housing for introducing a first fluid into the interior space of the housing,a second inlet in the housing for introducing a second fluid into the interior space of the housing,means for dividing the interior space into first and second chambers with the first inlet communicating with the first chamber and the second inlet communicating with the second chamber,a first outlet in the housing for removal of the first fluid from the first chamber after heat exchange with the heat transfer structure, anda second outlet in the housing for removal of the second fluid from the second chamber after heat exchange with the heat transfer structure,wherein when the members are rotated and the first and second fluids are introduced into the associated chambers and spaces between the members, with the first fluid having a temperature greater than a temperature of the second fluid, the members are rapidly heated thereby removing heat from the first fluid and heating the second fluid.

15. The rotary heat exchanger of claim 14, wherein each member has a base with a material of a certain thermal conductivity, and at least a layer of material on the base with a thermal conductivity substantially greater than the certain conductivity.

16. The rotary heat exchanger of claim 14, wherein the means for dividing comprises a plurality of spacers that space the members a distance apart.

17. The rotary heat exchanger of claim 15, wherein the layer of material on the base is a metal.

18. The rotary heat exchanger of claim 17, wherein the metal is one of silver, copper or gold.

19. The rotary heat exchanger of claim 15, wherein each base is a disc having opposing surfaces and said layer of material is on each opposing surface.

20. The rotary heat exchanger of claim 14, wherein the first and second inlets are at opposite ends of the housing so that the first and second fluids can flow in opposite directions and counter to the rotation of the members.

21. The rotary heat exchanger of claim 15, wherein the layer of material has a plurality of ridges and grooves therein to promote turbulent flow of the fluids over the members.

22. The rotary heat exchanger of claim 14, wherein each member is coupled with a common shaft for rotation therewith.

23. The rotary heat exchanger of claim 16, further including seal structure associated with the spacers so as to provide a seal with respect to the members.

24. The rotary heat exchanger of claim 14, in combination with a motor, a controller and at least one sensor, the motor being constructed and arranged to rotate the means for transferring heat, the sensor being constructed and arranged to sense temperature changes within the heat exchanger, the sensor being constructed and arranged to send a signal to the controller such that the controller can control the speed of the motor to control a heat transfer rate of the heat exchanger.