Patent Application
20150316327
The invention generally relates to storing and releasing energy using solid-state materials and more particularly relates to heating or cooling using solid-state materials.
In a variety of activities there is a need to maintain temperatures of certain items or spaces within in preselected range while the ambient temperature fluctuates. In many cases, these items or spaces exist in regions where electricity and other energy sources are generally unavailable or unreliable. A variety of mechanisms have been utilized and developed to provide selected heating or cooling functions to a particular space or item. However, each of these other systems is characterized by problems that need to be accounted for. For example, ice can be used for cooling, but ice melts and requires extreme temperatures for re-freezing. Refrigeration compressors, on the other hand, are currently the dominant mechanism used for cooling. However, they have moving parts that wear out, they require an external power supply, and they consume refrigerant fluids that are often strong sources of greenhouse gasses. A new system is needed for alternatively providing passive cooling and/or heating, for example, in remote desert environments where electricity is unavailable or unreliable.
Additional advantages and novel features of the present invention will be set forth as follows and will be readily apparent from the descriptions and demonstrations set forth herein. Accordingly, the following descriptions of the present invention should be seen as illustrative of the invention and not as limiting in any way.
It is an object of the present invention to provide repeatable cooling or heating cycles in environments where electricity may not be available. The present invention comprises at least one solid member made of a material that undergoes a phase change when heat is released or absorbed, a locking member that selectively holds the solid member in a desired phase, a heat exchange medium in contact with the at least one solid member, and a chassis to hold the at least one solid member in mechanical communication with the locking member. In this embodiment, the at least one solid member is held in a desired phase by the locking member and is selectively released to permit transition of the at least one solid member from one phase to the other phase to allow the solid member to absorb or release heat in the heat exchange medium.
In another embodiment, the present invention comprises at least one solid member made of a material that undergoes a phase change from a first phase to a second phase when heat is absorbed or released and a locking member that selectively holds the at least one solid member in a desired phase. In this embodiment, the at least one solid member is held by the locking member in the second phase and is selectively released to permit transition of the solid member from the first phase to the second phase resulting in the solid member absorbing or releasing heat.
In another embodiment, the invention comprises a plurality of solid members made of a material that undergoes a phase change from a first phase to a second phase, thereby absorbing heat from ambient air in contact with the solid members, one or more locking members that holds at least one of the solid members in the first phase, wherein the locking members can be selectively released at a predetermined time allowing the solid members to absorb heat from the ambient air, a chassis to hold the solid members in mechanical communication with the locking members, a plurality of wheels physically coupled with the chassis to support the chassis, thereby allowing the system to be reversibly moved from a first preselected location wherein the ambient air is below about 60° F. to a second preselected location wherein the ambient air is above about 75° F. In this embodiment, in the first preselected location the solid members transition to the first phase, thereby releasing heat into the ambient air, and the solid members are held in the first phase by the locking members; and in the second preselected location one or more locking members can be selectively released to allow transition of at least one of the solid members to the second phase, thereby allowing the solid members to absorb heat from the ambient air.
In other embodiments of the invention, the heat exchange medium is selected from the group consisting of air, water, or alcohol. In another embodiment of the invention, the at least one solid member has a heat absorption capacity of about 100,000 kJ to 200,000 kJ. In another embodiment, the at least one solid member is in the form of a rod, a sheet, a tube, or a block. In another aspect, the at least one solid member is comprised of a nickel titanium alloy.
The purpose of the foregoing abstract is to enable the United States Patent and Trademark Office and the public generally, especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
Various advantages and novel features of the present invention are described herein and will become further readily apparent to those skilled in this art from the following detailed description. In the preceding and following descriptions, preferred embodiments of the invention are shown and described by way of illustration of the best mode contemplated for carrying out the invention. As will be realized, the invention is capable of modification in various respects without departing from the invention. Accordingly, the drawings and description of preferred embodiments set forth hereafter are to be regarded as illustrative in nature, and not as restrictive.
The present invention is a system for heating or cooling that employs solid-state rods that release or absorb latent heat during a phase transition. The present invention addresses a need for a heating or cooling system that uses no electricity, thus allowing, for example, for remote deployment. The present invention provides a solution for cost effective, energy efficient, and environmentally friendly operation compared to prior art since it does not require an external energy source such as a generator, fuel, or electrical power. As a cooling system, the invention is useful in a desert environment where large variations exist between daytime and nighttime temperatures. In the following description, embodiments of the present invention are shown and described by way of illustration of the best mode contemplated for carrying out the invention. It will be apparent that various modifications and alternative constructions to the present invention may be made. Therefore the description should be seen as illustrative and not limiting. The present invention is intended to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.
Solid member 2 includes a bi-metal alloy of nickel and titanium (NiTi). The NiTi alloy has a density of about 6400 kg/m3 and a latent heat up to about 21 kJ/kg. The NiTi alloy includes an atomic ratio for each metal of the bi-metal alloy given by [(50+X):(50−X)], where X=0 to 10. In a preferred embodiment, the composition of the bimetal alloy is about 50% Ni and about 50% Ti. Solid member 2 undergoes a phase transition at a temperature of about 60° F. In other embodiments, the phase transition temperature may be as low as about 40° F. and as high as about 80° F. After undergoing the change from the first phase to the second phase during which heat is released, the length of the solid member 2 decreases by about 5%-7%, after which the locking member 4 can be engaged to lock the solid member 2 into the second phase by mechanical stress. In other embodiments, length of the solid member 2 may decrease by up to about 10% in the second phase compared to the length in the first phase.
In a preferred embodiment, the solid member 2 is in the shape of a cylindrical rod. A cylindrical rod shape is preferred because it lacks sharp corners or edges along its length that may lead to early fatigue of the solid member 2. The solid member 2 has a length-to-diameter ratio equal to or greater than about 10. In a preferred embodiment, the solid member 2 has a length of about 90 cm in the first phase and a diameter of about 4 cm. The volume the solid member 2 is therefore about 1130 cm3 in the first phase.
The solid member 2 may include various shapes suitable for embodiments of the present invention. Shapes suitable for use include: rods, sheets, tubes, pipes, blocks, or other structured forms. Structured forms may be fashioned by various processes including, but not limited to, for example, pressing, pelletizing, casting, extruding, stretching, bending, twisting, or combinations of these various processes. Different shapes may be desirable depending on the needs of the user or the particular embodiment. Thus, the description is not intended to be limiting.
The NiTi alloy is polycrystalline. Typical crystal grain sizes of the solid member 2 range from several microns to several hundreds of microns, although this is not intended to be limiting. The preferred crystal grain orientation of the solid member 2 is in the [111] direction, i.e. along the axial direction of the rod. It is known to those with ordinary skill in the art that this grain orientation yields a higher coefficient of performance (COP). It is further known to those with ordinary skill in the art that the manufacture process of the solid member 2 affects the grain size and orientation.
The manufacturing process of the solid member 2 includes, but is not limited to, casting, annealing, sizing, and cold drawing. The solid member 2 is formed by a method of induction melting and/or arc melting, preferably in a casting crucible devoid of carbon and in an environment devoid of oxygen. After melting, the alloy is homogenized at a temperature of about 900° C. to 1200° C. for about 2 to 4 hours. The alloy is then allowed to air cool. The alloy is then subject to cold drawing to form a rod. The rod may need an additional heat treatment to prompt the shape memory effect and to adjust the phase transition temperature and latent heat. Carbon included during the melting process as an impurity may form titanium carbide (TiC). It is generally desirable to prevent the formation of TiC during manufacture, because TiC inclusions tend to reduce the fatigue life of the final solid member 2. The control and limitation of carbon during manufacture is generally accomplished through control of the carbon content of the casting crucible. Oxygen included during the melting process as an impurity may form titanium oxide (TiO). It is generally desirable to prevent the formation of TiO during manufacture, because TiO inclusions tend to reduce the fatigue life of the solid member 2. The control and limitation of oxygen during manufacture is accomplished by controlling the gas environment of the furnace. In a preferred embodiment, carbon impurities are limited to a level no higher than about 500 ppm. In a preferred embodiment, oxygen impurities are limited to a level no higher than about 500 ppm. In alternative embodiments, carbon impurities are limited to about 4000 ppm and oxygen impurities are limited to about 4000 ppm.
The solid member 2 may be constructed of, for example, alloys and metal-containing alloys that provide preselected changes in enthalpy for intended applications. In some embodiments, alloys include metals and materials including, but not limited to, e.g., nickel (Ni), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), strontium (Sr), zirconium (Zr), palladium (Pd), hafnium (Hf), platinum (Pt), bismuth (Bi), carbon (C), oxygen (O), including combinations of these materials. In some embodiments, the alloy is a bi-metal alloy. In other embodiments, the alloy contains multiple metals or is a multi-component alloy. Other alloys are within the scope of the invention. For example, solid member 2 may be comprised of alloys such as, for example, CuAlNi, CuZnAl, NiMnGa, or NiMnSn. Thus, no limitations are intended.
The locking member 4 is in mechanical communication with the solid member 2 such that the locking member 4 is able to retain the solid member 2 in the second phase when the solid member 2 is of decreased length compared to the first phase. When released, the locking member 4 is able to allow the length of the solid member 2 to increase as the solid member 2 transitions to the first phase. The solid member 2 generates about 800 MPa of stress when secured by the locking member 4 in the second phase. In a preferred embodiment in which the solid member 2 is a cylindrical rod with a diameter of 4 cm and a cross sectional area of about 12.56 cm2, the force required to retain the solid member 2 in the second phase is about 10000 Newtons. In other embodiments, the force required to retain the solid member 2 in the second phase may be affected by the properties of the solid member 2. For example, as known by those with ordinary skill in the art, such properties may include, but are not limited to, the cross-sectional area, composition of the metallic alloy, inclusion of impurities, grain size, grain direction, and combinations of these various properties and factors.
The heat exchange medium 6 is air that is in thermodynamic contact with the solid member 2 thereby absorbing or releasing heat from the solid member 2 and undergoing a change in temperature ΔT. In other embodiments, the heat exchange medium 6 may be water, organic liquids such as ethanol, or other heat exchange media or combinations thereof. No limitations are intended.
Solid member supports 12 are in mechanical communication with the solid member 2 to hold the solid member 2 in a predetermined location and orientation within the interior region 10 of the chassis 8. Solid member supports 12 may be made of steel (e.g., stainless steel), aluminum, plastic, other rigid supporting materials, or combinations of these materials.
In a preferred embodiment, the solid member supports 12 provide a means to prevent the solid member 2 from buckling, deforming, warping, bending, or otherwise deviating from a preferred orientation and/or shape while under stress while locked in the second phase by the locking member 4. The solid member supports 12 may attach to the top 22 and the bottom 24 of the chassis 8. The solid member supports 12 are in mechanical communication with a plurality of solid members 2. Each solid member 2 is in mechanical communication with a plurality of solid member supports 12.
In an alternative embodiment, the solid member supports 12 are in mechanical communication with at least one solid member 2. In an alternative embodiment, each solid member 2 is in mechanical communication with at least one solid member support 12. In other embodiments, the solid member supports 12 are attached to any one or combination of the top 22, bottom 24, and one or more sides 18 and 20 of the chassis 8. No limitations are intended.
In the system illustrated in
In the system illustrated in
In another embodiment, the chassis 8 may be in the form of a rack with a frame (not shown) with no top and no bottom, which may, for example, be mounted to a wall, floor, or ceiling, or which may, for example, be leaned against a wall or held upright by an A-frame. In other embodiments, the chassis 8 may be a carriage, cabinet, case, body, chest, or trunk. Other modes of containment deemed desirable for different embodiments may be used. No limitations are intended.
In other embodiments, various numbers of solid members 2 can be locked and unlocked by components of each locking member 4. For example, as shown in
In the instant embodiment, chassis 8 includes an open front, which allows the heat exchange medium 6 to be in contact with each of the solid members 2 permitting exchange of latent heat as detailed herein.
In a preferred embodiment, the invention may have four wheels 16 attached at or near each corner of the bottom 24 of the chassis 8 to provide mechanical support or to allow portability, but is not intended to be limited thereto. To support the load of the invention in the preferred embodiment, each of the four wheels 16 may have a load capacity of at least about 2000 kg. In an alternate embodiment, the invention may have three or more wheels 16 attached to the bottom 24 of the chassis 8. In various embodiments, the wheels 16 may swivel, and/or the wheels 16 may have a locking mechanism that can be engaged to prevent undesired motion.
In another embodiment, the wheels 16 may be attached to any side or combination of sides of the chassis 8. For example, but not intended to be limiting, an embodiment of the invention may have wheels 16 attached to the left side 18 of the chassis 8. In this example, the chassis 8 may be oriented on the wheels 16 such that the solid members 2 are oriented vertically. In another embodiment of the invention, the wheels 16 may be attached to any one or more of sides of the chassis 8 to allow flexibility in orientation or portability of the chassis 8. However, no limitations are intended.
As illustrated in
As illustrated in
In alternative embodiments, not intended to be limiting, the locking members 4 may be arranged to engage through the left side 18 of the chassis 8 as described previously in reference to
In another alternative embodiment, the solid members 2 may be oriented vertically and the locking members 4 arranged on the top 22 of the chassis 8. No limitations are intended.
In a preferred embodiment, a 90 cm long solid member 2 in the form of a cylindrical rod will change in length by about 4 cm to 7 cm when transitioning from the first phase to the second phase. The threaded bar 26 is of a predetermined length such that the threaded bar 26 can travel at least 4 cm to at least 7 cm to allow the solid member 2 to be locked into the second phase when the threaded bar 26 is in the locked position and, further, to allow the solid member 2 to transform into the first phase when the threaded bar 26 is in the unlocked position. In an alternative embodiment, the threaded bar 26 is of a predetermined length such that the threaded bar 26 can travel a sufficient distance to move between the locked position and the unlocked position, which allows a solid member 2 (with a predetermined change in length during phase transition) to transition from the second phase to the first phase.
The solid member 2 is held fixed at one end by a solid member support 12 and in mechanical communication with the left side 18 of the chassis 8, as detailed previously in reference to
In an alternative embodiment, a loading member 31 is mechanically affixed to the end of the solid member 2 such that when the locking handle 14 is in the locked position the threaded bar 26 is in mechanical communication with the loading member 31 with force transmitted through the loading member 31 to the entire cross-section of the solid member 2 to lock the solid member 2 into the second phase. Further, in the unlocked position, the loading member 31 remains mechanically affixed to the solid member 2.
In an alternative embodiment, the connection beam 30 is mounted to the interior surface of the right side 20 of the chassis 8. In an alternative embodiment, hole 28 is a threaded hole designed to mate with the threaded bar 26. Such an embodiment may be desired if, for example, the right side 20 of the chassis 8 is a predetermined thickness such that the hole 28 can accommodate enough threads to adequately engage the threaded bar 26. In such an embodiment, the connection beam 30 may be optional. In a preferred embodiment, the locking member 4 is comprised of steel. In alternative embodiments, the locking member 4 is comprised of one or more of, but not limited to, steel, stainless steel, aluminum, plastic, or any other predetermined rigid material.
Other embodiments of the invention can use different types of locking members 4. For example, but not intended to be limiting, the locking member 4 may be comprised of a sliding apparatus, such as comprising solid rods, sheets, or pins, which may be used to engage the loading member 31, thereby locking the solid members 4 into the first phase. Further, the solid members 4 can be unlocked by removing the sliding apparatus. Other locking members include, but are not limited to, those that incorporate latches, bolts, screws, hasps, or cams.
In a preferred embodiment, the heat exchange medium 6 is air, and the heat exchange medium circulation device 32 forces the air 6 into or out of the interior region 10 such that the air is in thermal contact with at least one solid member 2 before emerging from the interior region 10.
In a preferred embodiment, the heat exchange medium circulation device 32 is a propeller blade fan. In alternative embodiments, the heat exchange medium circulation device 32 may be, but is not intended to be limited to, an automatic or electric powered device such as a revolving blade fan, a centrifugal fan, a cross-flow fan, or any other automatic device for moving or circulating air.
In other embodiments, the heat exchange medium circulation device 32 may be, but is not intended to be limited to, a manual device such as a bellows, a fan blade rotated by a foot-driven belt, a hand-held fan made of a material such as paper or feathers, or any other manually-powered device for moving or circulating air. In alternative embodiments, air 6 can be forced into one side of the chassis 8 and back out an adjacent side or back out the same side.
In an alternative embodiment, the invention may be completely passive and rely on natural convective motion of air 6 through the interior region 10. In other embodiments, the heat exchange medium circulation device 32 may be a device that circulates water, organic liquids such as ethanol, or other heat exchange media or combinations thereof. No limitations are intended.
As illustrated in
During the day, as illustrated in
In another embodiment illustrated in
In
In
In another embodiment, not intended to be limiting, both doors 36 and 38 may be opened simultaneously. For example, opening both doors on a warm, breezy day may allow outside air to pass through the interior region (not shown) to make thermal contact with the solid members 2 (not shown) (described in reference to
In other embodiments of the invention, the doors 36 and 38 may be oriented horizontally such that they swing outward and upward from the chassis 8. Other embodiments may include, but are not intended to be limited to, doors of any orientation that are: swinging doors, sliding doors, folding doors, or roll-up doors. Other embodiments may employ insulated doors to minimize undesired heat transfer through a closed door.
For example,
While various preferred embodiments of the invention are shown and described, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims.
This application is a Continuation-In-Part and Divisional of U.S. patent application Ser. No. 13/076,257 filed Mar. 30, 2011, now allowed, which is incorporated in its entirety by reference herein.
This invention was made with Government support under Contract DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13076257 | Mar 2011 | US |
| Child | 14796252 | US |
