Patent Description
HEAT PUMP
BACKGROUND
Technical Field of the Invention:
[0001] The present invention is related in general to heat transfer apparatus and methods, and more specifically to heat pumps for moving heat from one environment to another environment.
State of the Prior Art
[0002] A heat pump generally comprises a system with an evaporator, a compressor, a condenser, a throttle valve (sometimes called an expansion valve), and a cooling medium or heat transfer fluid that circulates through the components in the system. By evaporating the heat transfer fluid in the evaporator and condensing it at a higher pressure, thermal energy (i.e., heat) can be taken into the heat transfer fluid at a lower energy (evaporation heat, which is also known as heat of vaporization) and given off at a higher pressure (condensation heat, which is also known as latent heat of condensation). Such systems, while effective and durable, generally are significantly less efficient than the theoretical maximum. Also, the complexities of such systems generally require numerous precision parts, which increase the cost of such systems and require special tools for maintenance and repair. Also, such systems require relatively large volumes of refrigerant (e.g., R134a or R410a), which can leak and cause damage to the atmosphere.
[0003]
Heat pumps that utilize centrifugal compressors are also sometimes called centrifugal chillers. Centrifugal chillers typically range in size from 100 to 10,000 tons of refrigeration, and they provide some advantages and better efficiencies when used in large installations, such as commercial buildings. The reliability of centrifugal chillers is high, and the maintenance requirements are low, because centrifugal compression involves purely rotational motion of only a few mechanical parts. A disadvantage of centrifugal chillers is that efficiencies decrease as the loads decrease. Also, centrifugal chiller systems often utilize a second heat transfer fluid to move heat from the condenser to a cooling tower and sometimes also a third heat transfer fluid for moving heat from a living space or other space to the evaporator.
[0004] The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art and other examples of related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate some, but not the only or exclusive, example embodiments and/or features of or relating to vortex sensor units and implementations of such vortex sensor units in flowmeter apparatus. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting. In the drawings:
[0006] Figure 1 is an isometric view of an example rotatable heat pump wheel installed in a partition;
[0007] Figure 2 is an isometric view of the example rotatable heat pump in Figure 1, but from a different perspective;
[0008] Figure 3 is a front elevation view of the example rotatable heat pump in Figures 1 and 2;
[0009] Figure 4 is a side elevation view of the example rotatable heat pump in Figures 1-3;
[0010] Figure 5 is rear elevation view of the example rotatable heat pump in Figures 1-4;
[0011] Figure 6 is an enlarged cross-section view of the example fluid flowmeter in Figures 1-5 taken along the section cut plane 6-6 in Figure 4;
[0012] Figure 7 is an isometric view of an example alternative embodiment of the rotatable heat
pump similar to Figure 2, but with fan blades on the thermally conductive material of the first wall; and
[0013] Figure 8 is an isometric view of the example alternative embodiment of the rotatable heat pump similar to Figure 1, but with fan blades on the thermally conductive material of the second wall.
DETAILED DESCRIPTIONS OF EXAMPLE EMBODIMENT
[0014] An example rotatable heat pump 10 is illustrated in Figures 1 and 2 mounted in a partition 12 for transferring thermal energy (heat) from a first space 14 on a first side of the partition 12 to a second space 16 on a second side of the partition 12, such as a wall in a building or a bulkhead in a machine. The example rotatable heat pump 10 is mounted on a drive shaft 18 for rotation about an axis of rotation 20 as indicated, for example, by the rotation arrow 22. The direction of rotation is not critical, so the rotation could be in the opposite direction. The example rotatable heat pump 10 is illustrated as round like a wheel so that it can rotate in an aperture 24 in a partition 12 with a close tolerance between the partition 12 and the periphery of the rotatable heat pump 10. Any kind of a prime mover (not shown), such as a motor, belt, hear, or other motive device can be used to rotate the rotatable heat pump 10.
[0015) Referring now primarily to Figures 3-6, the example rotatable heat pump 10 is comprised of a disk 26 mounted on the drive shaft 18 and sandwiched between a first wall 28 and a second wall 30, and, as best seen in Figure 6, the disk 26 has at least one cavity 32, which forms and functions as a heat pipe 34 as will be explained in more detail below. For most applications, the disk 26 has multiple cavities 32, which form and function as multiple heat pipes 34, as illustrated, for example, in Figure 6. Each of the cavities 32, i.e., each of the heat pipes 34, contains a working fluid 36 that transfers heat radially from an evaporator section 38 in a radially outward portion of the heat pipe 34 to a condenser section 40 in a radially inward portion of the heat pipe 34, as will be explained in more detail below. In the example rotatable heat pump 10, each of the plurality of cavities 32, thus the plurality of heat pipes 34, is the same as the others, so, to avoid unnecessary clutter in Figure 6, one representative heat pipe 34 has its component parts numbered, with the understanding that the other heat pipes 34 have similar component parts, but not all of such similar component parts are numbered.
[0016] The first wall 28 has a radially inward portion 42 comprising a thermal insulating material positioned adjacent to the condenser section(s) 40 of the heat pipe(s) 34 and a radially outward portion 44 comprising a thermally conductive material positioned adjacent to the evaporator section(s) 38 of the heat pipe(s) 34. The second wall 30 has a radially inward portion 46 comprising thermally conductive material adjacent to the condenser section(s) 40 of the heat pipe(s) 34 and a radially outward portion 48 comprising a thermal insulating material adjacent to the evaporator section(s) of the heat pipe(s) 34. Accordingly, thermal energy (i.e., heat) can be conducted from the first space 14 (see Figures 1 and 2) through the thermally conductive material of the radially outward portion 44 of the first wall 28 to the evaporator section 38 of the heat pipe 34, but not through the thermal insulating material of the radially inward portion 42 of the first wall 28 to the condenser section 40 of the heat pipe 34. Further, thermal energy (i.e., heat) can be conducted from the condenser section 40 of the heat pipe 34 through the thermally conductive material of the radially inward portion 46 of the second wall 30 to the second space 16, but not through the thermal insulating material of the radially outward portion 48 of the second wall 30. While the terms thermally conductive and thermal insulating do not necessarily have specific thermal conductivity values and thermal resistivity values, once persons skilled in the art read this description and understand the operating principles of the example rotatable heat pipe 10 described, such persons skilled in the art will understand the terms thermally conductive and thermal insulating in this context and will be aware of myriad materials that can provide the functions described. In general, the thermally conductive materials of the radially outward portion 44 of the first wall 28 and of the radially inward portion 46 of the second wall 30 are more thermally conductive than the thermal insulating materials of the radially inward portion 42 of the first wall 28 and of the radially outward portion 48 of the second wall 30.
[0017] The working fluid 36 can be any fluid that has both a vapor phase and a liquid phase within the desired operating temperature range of the rotatable heat pump 10, and each of the heat pipes 34 is partially filled with the working fluid 36 so that the heat pipe 34 contains both vapor and liquid over the desired operating temperature range. Examples of particular working fluids for particular operating temperature ranges are well-known to persons skilled in the heat pipe art and are available in publications. For room temperature applications, some example working fluids include ammonia (213-373 K), alcohol (methanol (283-403 K) or ethanol (273 403 K), or water (298-573 K). The volatility of the working fluid can also be tuned to operate within desired temperature ranges by adjusting the amount of vacuum, i.e., operating pressure, in the heat pipe(s) 34, as will be understood by persons skilled in the art once they have read this description and understand the operating principles of the example rotatable heat pump 10 as explained in this description and illustrated in the drawings. Other working fluids are known for lower temperature applications and for higher temperature applications. In the example rotatable heat pump 10, the disk 26 has a hole 50 through the peripheral surface of the disk 26 into each of the heat pipes 34, which can be used to evacuate and then partially fill the heat pipes 34 with the working fluid 36, and plugs 52 are provided to then plug the holes 50. The disk 26 and the first and second walls 28, 30 can be assembled and fastened together in any manner that creates a vacuum-tight seal between the disk 26 and each of the walls 28, 30 to enable the heat pipe(s) 34 to hold a vacuum and to contain the vapor and liquid phases of the working fluid 36 without leaks. Other structures and methods can also be used to form or construct the rotatable heat pump 10 in a manner that provides the heat pipe(s) 34 and the respective thermally conductive and thermal insulating portions 42, 44, 46, 48 adjacent to the respective evaporator section(s) 38 and condenser section(s) 40 of the heat pipe(s) 34 as explained above.
[0018] In operation, the example rotatable heat pump 10 is rotated as indicated by the rotation arrows 22 fast enough for the liquid phase 54 of the working fluid 36 to be forced radially outward into the evaporator section(s) 38 of the heat pipe(s) 34, as illustrated diagrammatically in Figure 6. As air flows over the first wall 28 of the rotatable heat pump 10, as illustrated by the flow arrows 55 in the first space 14 in Figures 1 and 2, thermal energy (i.e., heat) from the air is conducted through the thermally conductive, radially outward portion 44 of the first wall 28 to the liquid phase 54 of the working fluid 36 in the evaporator section(s) 38 of the heat pipe(s) 34. The additional thermal energy provides heat of vaporization to the liquid phase working fluid 54 so that some of the liquid phase working fluid 54 in the heat pipe(s) 34 vaporizes, which increases the local vapor pressure in the evaporator section(s) 38 of the heat pipe(s) 34. At the same time, vapor 56 of the working fluid 36 in the condenser section(s) 40 of the heat pipe(s) 34 condenses to liquid phase working fluid, as illustrated diagrammatically by the droplets 58 in Figure 6, which is then driven by centrifugal force out of the condenser section(s) 40 and into the evaporator section(s) 38, as illustrated diagrammatically by the droplets 60 in Figure 6. The condensation of the vapor phase working fluid to the liquid phase working fluid involves the working fluid giving up the latent heat of condensation, which is conducted by the thermally conductive, radially inward portion 46 of the second wall 30 to air in the second space 16 (see Figure 1). The condensation of vapor phase working fluid 56 to liquid phase working fluid 58 in the condensation section(s) 40 of the heat pipe(s) 34 lowers the local vapor pressure of the working fluid in the condenser section(s) 40 of the heat pipe(s) 34. Therefore, the higher local vapor pressure in the evaporator section(s) 38 as compared to the lower local vapor pressure in the condenser section(s) 40 drives the vapor phase of the working fluid in a convection flow from the evaporator section(s) 38 to the condenser section(s) 40 to continue the heat transfer process from the evaporator section(s) 38 to the condenser section(s) 40 as heat of vaporization is pulled from the first space 14 through the thermally conductive, radially outward portion 44 of the first wall 28 and latent heat of condensation given up by the condensing working fluid is conducted by the thermally conductive, radially inward portion 46 of the second wall 30 to the air in the second space 16. Flowing air in the spaces 14, 16 over the respective walls 28, 30 of the rotatable heat pump 10, as illustrated by the air flow arrows 55, 57 in Figures 1 and 2, can enhance the heat transfer process from the first space 14 to the evaporator section(s) 38 of the heat pipe(s) 34 and from the condenser section(s) 40 of the heat pipe(s) 34 to the second space 16. The thermal insulating, radially inner portion 42 of the first wall 28 prevents transfer of latent heat of condensation from the condenser section(s) 40 back into the first space 14, while the thermal insulating, radially outer portion 48 of the second wall 30 prevents transfer of heat from the second space 16 into the evaporator section(s) 38 of the heat pipe 34, so the overall net flow of heat is from the first space 14, through the heat pipe(s) 34, and into the second space 16.
[0019] In Figures 7 and 8, the example rotatable heat pump 10 is shown equipped with a plurality of heat input fan blades 62 mounted on the external surface of the radially outward portion 44 of the first wall 28. As the heat pump rotates, those heat input fan blades 62 enhance the air flow 55 in the first space 14 on and adjacent to the first wall 28, which enhances heat transfer from the first space 14 into the evaporator section(s) 38 of the heat pipe(s) 34. Also, a plurality of heat output fan blades 64 are mounted on the external surface of the radially inward portion 46 of the second wall 30. As the heat pump 10 rotates, those heat output fan blades 64 enhance the air flow 57 in the second space 16, which enhances heat transfer from the condenser section(s) 40 of the heat pipes 34 into the air on and adjacent to the second wall 30, thus enhances heat transfer from the condenser section(s) 40 to the air in the second space 16.
[0020] The foregoing description provides examples that illustrate the principles of the invention, which is defined by the features that follow. Since numerous insignificant modifications and changes will readily occur to those skilled in the art once they understand the invention, it is not desired to limit the invention to the exact example constructions and processes shown and described above. Accordingly, resort may be made to all suitable combinations, subcombinations, modifications, and equivalents that fall within the scope of the invention as defined by the features. The words “comprise,” “comprises,” “comprising,” “include,” “including,” and “includes” when used in this specification, including the features, are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, or groups thereof. Also, directional terms such as “over”, “above”, “below”, “upper”, “front”, “lateral”, and others that refer to orientations or relative positions in views in the drawings are not intended to limit the rotatable heat pump 10 to use in any particular orientation.
CLAIMS
I claim:
1. A rotatable heat pump, comprising:
at least one heat pipe extending a distance radially with respect to an axis of rotation and positioned between a first wall and a second wall, a radial inward portion of the heat pipe comprising a condenser section of the heat pipe and a radial outward portion of the heat pipe comprising an evaporator section of the heat pipe, wherein the first wall comprises a thermally insulating material adjacent to the condenser section of the heat pipe and a thermally conductive material adjacent to the evaporator section of the heat pipe, and wherein the second wall comprises a thermally conductive material adjacent to the condenser section of the heat pipe and a thermally insulating material adjacent to the evaporator section of the heat pipe; and a volatile heat transfer fluid in the heat pipe.
2. The rotatable heat pump of claim 1, wherein the heat pipe is formed by a cavity in a disk that is sandwiched between the first wall and the second wall.
3. The rotatable heat pump of claim 1, including a plurality of fan blades mounted on the thermally conductive, radially outward portion of the first wall,
4. The rotatable head pump of claim 1, including a plurality of fan blades mounted on the thermally conductive, radially inward portion of the second wall.
5. A method of transferring heat from a first space to a second space, comprising:
positioning a heat pump between the first space and the second space such that a first wall of the heat pump is adjacent to the first space and a second wall of the heat pump is adjacent to the second space, wherein the heat pump comprises a plurality of heat pumps positioned between the first wall and the second wall and spaced angularly about an axis with each of the heat pumps extending radially from a condenser section to an evaporator section, and wherein:
(i) an outward portion of the first wall adjacent to the evaporator sections of the heat pumps is more thermally conductive than an inward portion of the first wall adjacent to the condenser sections of the heat pumps; and (ii) an inward portion of the second wall adjacent to the condenser section of the heat pumps is more thermally conductive than an outer portion of the second wall adjacent to the evaporator sections of the heat pumps; and rotating the heat pump about the axis at a sufficient speed to cause a volatile fluid.
6. The method of claim 5, including positioning the heat pump in a partition between the first space and the second space.
ABSTRACT OF THE DISCLOSURE
A rotatable heat pump includes heat pumps mounted between a first wall and a second section and an evaporator section, the evaporator section being radially outward from the axis farther than the condenser section. A volatile fluid partially fills each of the heat pipes. The first wall comprises a thermally insulating material adjacent to the condenser section of the heat pipe and a thermally conductive material adjacent to the evaporator section of the heat pipe, and the second wall comprises a thermally conductive material adjacent to the condenser section of the heat pipe and a thermally insulating material adjacent to the evaporator section of the heat pipe.