Abstract:
A method and apparatus for storing, transporting, and releasing high grade, thermodynamically useful energy for a wide variety of uses. Solar energy is collected and reflected onto a heat storage container using a three-mirror reflecting system. This invention involves a method of heating the heat storage container using a primary, secondary, and tertiary system, which has a core that is partially comprised of an aluminum alloy and a metallic shell with a higher melting point than the aluminum alloy contained within. Once heated, the storage containers can then be transported to different storage areas in order to heat secondary storage containers or can be used in processes such as cooking, powering heat engines, water heating, absorption refrigeration, or drying garbage, waste, or biomass.

Description:
RELATED APPLICATION DATA 
     This application is related to Provisional Patent Application Ser. No. 60/599,983 filed on Aug. 9, 2004, and priority is claimed for this earlier filings under 35 U.S.C. §120. The Provisional Patent Application is also incorporated by reference into this utility patent application. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     An apparatus and method for capturing solar energy within a heat storage container in order to effectively and efficiently utilize the resulting heat energy by transporting, storing, and putting the energy to productive use. 
     BACKGROUND OF THE INVENTION 
     Conventional systems of photovoltaics and solar heating are hampered by high cost, low efficiency, unpredictable power output, and the need for backup power or heat sources. Much of the energy consumption in the modern age revolves around climate control, refrigeration, and the cooking of food. Solar energy potentially offers an important source of heat energy. However, collection and storage for later use has been difficult and elusive. A flexible, efficient, and effective system of collection and storage would offer expanded options for utilizing solar energy. 
     Many buildings and other fixed and mobile structures can potentially use a solar power based system for collecting heat energy for later use. A light-weight, practical system for collecting and storing solar energy offers numerous applications. Large buildings such as industrial parks, factories and similar installations could use solar energy for heating, cooling, or industrial applications. Large buildings such as found with large retail outlets, factories, or warehouse could install solar energy collection facilities on their roofs to collect solar energy. 
     The modern military relies on both portable and semi-portable kitchens to provide food for forces in the field. Such systems are equipped with either electric heating elements or gas burners. Associated disadvantages of such systems include the need for fuel and the corresponding logistical problems of supplying the necessary fuel to various military encampments all over the world. A solar-based cooking and heating system would offer important advantages. 
     This invention provides a system for independently producing heat as well as providing for a consumable source of electricity that includes fixed, mobile, or semi-mobile embodiments. The self-contained solar heat collection storage system can collect heat used to cook food, power heat engines, facilitate absorption refrigeration or adsorption cooling, heat water, and dry out garbage, waste, and biomass. The resulting heat source is non-toxic, non-explosive, and reusable. Such a system would offer expanded, practical applications for solar energy by effectively and efficiently collecting heat and storing that heat for later use. 
     SUMMARY OF THE INVENTION 
     This invention absorbs, stores, transports, and releases high-grade thermodynamically useful solar energy for a wide variety of uses. The invention consists of a method of heating heat storage containers using a solar radiation collection mirror array to heat the heat storage containers, which have cores that are partially composed of an aluminum alloy mixture. 
     In this invention, the storage containers are rotated in and out of a solar energy collection point by a conveyor system and can then be transported to different storage areas to heat secondary storage containers or to be used in processes such as cooking, powering heat engines, water heating, absorption refrigeration, or adsorption cooling. The energy collection point is located at a focal point of solar energy reflected and collected by a three-level reflector system of primary, secondary, and tertiary reflectors. The heat storage containers can also be used to dry garbage, waste, or biomass to be used for fuel or simply to facilitate disposal. The uses of the heat storage containers vary as the temperature levels change. As soon as an heat storage container cools to a non-useful temperature, it is recycled through the system to absorb, store, and transport the energy so that it can be released and utilized in a highly efficient manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         FIG. 1  shows an embodiment of a three-mirror level mirror system that includes multiple primary mirrors; 
         FIG. 2  shows an embodiment using multiple secondary and tertiary reflecting mirrors; 
         FIG. 3  shows another embodiment of  FIG. 2  wherein multiple secondary mirrors reflect solar energy to a single tertiary mirror; 
         FIG. 4  shows an embodiment comprised of an inflatable parabolic mirror with a transfer tube mounted in the center; 
         FIG. 5  shows an embodiment with a primary and secondary parabolic mirror supported by legs and struts; 
         FIG. 6  shows increased detail of the solar collection point and a combination secondary mirror and insulating lid; 
         FIG. 7  shows the embodiment of  FIG. 6  with the lid lowered into place; 
         FIG. 8  shows an embodiment of a heat storage container with a rigid metal outer shell; 
         FIG. 9  shows an embodiment of a heat storage container with a flexible carbon fiber outer shell; and 
         FIG. 10  is a graphic diagram showing the operation of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This invention is an energy absorption and distribution system in which mobile heat storage containers can be transported to areas in need of a clean and reliable source of energy. The invention uses a three-level arrangement of mirror reflectors to concentrate solar energy onto the mobile heat storage containers and conserve heat during this process. 
       FIG. 1  shows a basic arrangement for the invention that can be used on any flat surface. This flat surface can also be a building roof, vehicle roof (e.g. parked truck trailer, rail car, aircraft, etc), or other constructs. 
     An array of primary mirrors  5  are arranged on a mounting surface  7 . Although a flat surface is envisioned, other embodiments may be designed that are used on irregular surfaces. This primary mirror array  5  collects and concentrates solar energy onto a secondary mirror  10 . At least one of these mirrors (e.g. on each mirror in the entire mirror array  5  or the secondary mirror  10 ) are preferably equipped with a two-axis sun tracking mechanism  6  to more effectively collect solar energy, however, in some possible designs applications, the mirrors may be fixed. This tracking system  6  can be found at the interface between the underside of mirror  5  and platform  7 , or the backside of mirror  10  and its support structure  11 . 
     The solar energy is reflected from the secondary mirror  10  to a tertiary reflector  15 . The tertiary reflector  15  is a parabolic mirror that collects the solar energy from the secondary mirror  10  and reflects the collected energy onto an heat storage container  20 . There is an insulating lid  25  that fits over the top of the tertiary reflector  15 . The insulating lid  25  includes an automatic drop mechanism sensitive to either solar energy impacting the tertiary reflector  15  or the temperature of the heat storage container  20 . This drop mechanism will lower the insulating lid  25  over the storage container  20  to prevent heat loss caused by cloud cover or other loss of solar energy that leads to loss of heat from the heat storage container  20 , and reopen once that heat loss would cease. 
     The heat storage container  20  is moved from a solidified storage and return area  30  to the position above the tertiary reflector  15  by a conveyor system. The conveyor system passes through a first support leg  17  to above the tertiary reflector  15  where the heat storage container  20  is heated. Once the heat storage container  20  is heated and the metal alloy within it is molten or heated to a desired temperature, the conveyor system moves it down through a second support leg  18  to molten storage area  35 . The molten storage area  35  is insulated to help contain the heat of the heat storage containers  20 . These heated heat storage containers  20  are then moved from the heat storage area by the conveyor system or another conveyor or similar transporting system to a heat engine application  40  that usefully employs the heat energy. Potential applications include powering cooling applications, industrial applications, power applications, conductive heating, and radiant heating. After being used and cooled, the heat storage containers  20  are transported back to the solidified storage and return area  30  for recycling to reheat. 
       FIG. 2  shows an alternative embodiment of  FIG. 1  employing multiple secondary mirrors. An array of primary mirrors  105  are arranged on a mounting surface  107 . In this embodiment, the primary mirror array  105  collects and concentrates solar energy onto multiple secondary mirrors  110 . Such an arrangement can be used to more efficiently collect solar energy and it offers greater potential power since greater power production is available from this configuration. At least one set of these mirrors (e.g. each mirror in the entire mirror array  105  or the secondary mirror  110 ) are preferably equipped with a two-axis sun tracking mechanism to more effectively collect solar energy, however, in some possible designs applications, the respective mirror structures  105  or  110  may be fixed. 
     The solar energy is reflected from the secondary mirrors  110  to a corresponding tertiary reflector  115 . The tertiary reflectors  115  are a parabolic mirror collecting the solar energy from the secondary mirrors  110  to reflect the collected energy onto heat storage containers  120 . There is an insulating lid  125  that fits over the top of each of the tertiary reflectors  115 . The insulating lids  125  include an automatic drop mechanism sensitive to either solar energy impacting the tertiary reflectors  115  or the temperature of the heat storage container  120 . This drop mechanism will lower the insulating lids  125  over the storage containers  120  to prevent heat loss caused by cloud cover or other loss of solar energy that leads to loss of heat from the heat storage container  120  and reopens the lid once that loss of solar energy ceases. 
     The heat storage containers  120  are moved from a solidified storage and return area  130  to solar collection point above the tertiary reflector  115  by a conveyor system  131 . The conveyor system  131  passes through a first support leg  117  to above the tertiary reflectors  115  where the heat storage containers  120  are heated. Once the heat storage containers  120  are heated and the metal alloy within the containers  120  are molten or heated to a desired temperature, the conveyor system  131  moves down through a second support leg  118  to molten storage area  135 . The molten storage area  135  is insulated to contain the heat of the heat storage containers  120 . These heated heat storage containers  120  are then moved from the heat storage area by the conveyor system or another conveyor or similar transporting system to a heat engine application  140  that usefully employs the heat energy. After being used and cooled, the heat storage containers  120  are transported to the solidified storage and return area  130 . 
       FIG. 3  shows another embodiment alternative of  FIG. 1  employing multiple secondary mirrors. An array of primary mirrors  205  are arranged on a mounting surface  207 . In this embodiment, the primary mirror array  205  collects and concentrates solar energy onto multiple secondary mirrors  210 . At least one set of these mirrors (e.g. each mirror in the entire mirror array  205  or the secondary mirror  210 ) are preferably equipped with a two-axis sun tracking mechanism to more effectively collect solar energy, however, in this embodiment, each of the secondary mirrors  210  are mounted on a system that can shift the focus onto at least one single tertiary reflector  215  (e.g. at least two tertiary reflectors). 
     One deficiency in prior art applications is an inability to adapt to changing solar energy conditions caused by clouds. In this embodiment, the solar energy is reflected from several secondary mirrors  210  to a single tertiary reflector  215  and can be used to compensate for decreased solar energy (e.g. clouds) or to concentrate solar energy to achieve higher heat loads for specific requirements or demands. Other tertiary reflectors  250  (shown closed off) are available in this embodiment, but the available collected solar energy is concentrated upon a single tertiary reflector  215 . The tertiary reflectors  215  and  250  are parabolic mirrors collecting the solar energy from the secondary mirrors  210  to reflect the collected energy onto a single heat storage container  220 . There is an insulating lid  225  and  255  that fits over the top of each of the tertiary reflectors  215  and  250 . 
     The insulating lids  225  and  255  include an automatic drop mechanism sensitive to either solar energy impacting the tertiary reflectors  215  and  255  or the temperature of the heat storage container  220 . In this embodiment, this drop mechanism has lowered the insulating lids  255  over the tertiary reflectors  250 , either to contain remaining heat or simply to cover the conveyor mechanism during non-use. The insulating lids  225  and  255  lower over the storage containers  220  to prevent heat loss caused by cloud cover or other loss of solar energy that leads to loss of heat from the heat storage containers  220 . In further response, this embodiment repositions the secondary mirrors  210  focus onto the single tertiary reflector  215  to compensate for the loss of sunlight intensity and maintain the heat on a single, exposed heat storage container  220 . 
     The heat storage containers  220  are moved from a solidified storage and return area  230  to the position above the tertiary reflector  215  by a conveyor system  231 . The conveyor system  231  passes through a first support leg  217  to above the tertiary reflectors  215  where the heat storage containers  220  are heated. The support legs  217  are also present on the tertiary reflectors  250  that are sealed off, but it is envisioned that an automatic bypass system operates so that heat storage containers  220  are not moved into the inactive, closed tertiary reflectors  250 . Once the heat storage container  220  is heated and the metal alloy within the container  220  is molten or heated to a desired temperature, the conveyor system  231  moves it down through a second support leg  218  to a molten storage area  235 . This second support leg  218  is also present on the tertiary reflectors  250 , but the other legs are envisioned to be bypassed and not operating. The molten storage area  235  is insulated to contain the heat of the heat storage containers  220 , which can act to reheat other cooling heat storage containers  220 . These heated heat storage containers  220  are then moved from the heat storage area by the conveyor system or another conveyor or similar transport system to a heat engine application  240  that usefully employs the heat energy. After being used and cooled, the heat storage containers  220  are transported to the solidified storage and return area  230  for recycling and reheating. 
     In these embodiments shown in  FIGS. 1 ,  2 , and  3 , the size of the mirrors is primarily dependent on the power application and the attendant power generation desired for the system. To minimize wind loading on the secondary mirror&#39;s structure, the size of the mirrors preferably will be between one and four meters in diameter. However, the more important consideration for most applications will be required power. The mirrors may also be composed of a light-weight polished metal, such as aluminum, heavier construction such as polished stainless steel, mirrored glass, mirrored composite, or even individual replaceable modules assembled onto a base composite or skeletal structure to form the larger mirror structure. 
     An array of more than one primary mirror jointly aimed at an overhead secondary mirror offers significant advantages over a large single primary mirror system. Each primary mirror can move as needed to focus its reflected solar flux onto the secondary mirror. At times when less solar heat energy is required, one or more primary mirrors may be redirected to reduce total system heat flux. The secondary mirror can focus the solar energy to one or more heat receiving points where the heat storage containers can be heated to design temperature. The tertiary reflectors mounted below the containers to redirect solar radiation onto the containers helps to more efficiently capture available solar radiation and more evenly heat the containers. The upper lid which automatically closes when insufficient solar radiation is available helps to retain heat within the containers due to clouds or at the end of the day. 
     The conveyor system can also be fairly sophisticated to aid solar energy collection. During periods of high solar flux, it permits cyclically heating several containers at once for short intervals followed by a time of heat redistribution within each container to prevent the outer shell from being overheated by intense solar flux. During periods of low solar flux, one or more containers may remain static in the focal point for heating for longer periods to reach desired temperatures. Because the containers radiate heat outward, the ability of the conveyor system to heat a variable number of containers minimizes this heat loss, and offers the ability to operate under partly cloudy conditions. It is also possible to heat lower melting point containers during such conditions for lower temperature loads such as absorption refrigeration or other lower temperature applications. 
     In another embodiment that utilizes solar energy shown in  FIG. 4 , the mirror system comprises an inflatable or rigid parabolic mirror  310  that is approximately ten meters in diameter that has a transfer tube  320  located in the center of the circular structure. The transfer tube  320  is rigid and constructed of metal, ceramic material, or a composite. At the top of the transfer tube  320  is the secondary reflector  330  that reflects the solar rays from the parabolic mirror  310  down onto the collection point  340  as well as a tertiary reflector  360  that also reflects solar energy onto the collection point  340 , which is located at the top of the transfer tube  320 . In this embodiment, the secondary mirror  330  also acts as an insulating lid and will activate to lower down and fit over the tertiary reflector  360  when either the sunlight level is reduced or the temperature of the heat storage container falls. 
     The combination insulating lid/secondary mirror  330  seals off heat loss. This embodiment also has a conveyor system  350  that rotates heat storage containers into and out of the of the solar energy collection point  340 . A further refinement to this embodiment of the parabolic reflector adds a plastic cover forming a bubble over the entire mirror system. In this embodiment, the preferred size of the primary mirror is ten to three meters in diameter. The secondary mirror  330  may also include a two-axis tracking system for tracking the sun&#39;s movement. 
     Referring to  FIG. 5 , this embodiment shows another portable system. In this system, three rigid and height adjustable legs  405  support a parabolic mirror  410  that reflects solar energy onto a secondary mirror  420 . The secondary mirror  420  is attached to a triple support strut system  425 . Preferably, this system secondary mirror  420  reflects the collected solar energy down through an opening  412  in the secondary mirror  410 . The solar energy reflects from the secondary mirror  420  to a tertiary reflector  415 . The tertiary reflector  415  is a parabolic mirror that collects the solar energy from the secondary mirror  420  and reflects the collected energy onto a heat storage container  430 . 
     There is also an insulating lid  435  that fits over the top of the tertiary reflector  415 . The insulating lid  435  includes an automatic closing mechanism sensitive to either solar energy impacting the tertiary reflector  415  or the temperature of the heat storage container  430 . This closing mechanism will close the insulating lid  435  over the storage container  430  to prevent heat loss caused by cloud cover or other loss of solar energy that leads to loss of heat from the heat storage container  430  and reopen the insulating lid  435  once the solar energy increases. 
     The heat storage container  430  is moved from a solidified storage and return area  440  to the collection point above the tertiary reflector  415  by a conveyor system. The conveyor system passes through a first support leg  417  to above the tertiary reflector  415  where the heat storage container  430  is heated. Once the heat storage container  430  is heated and the metal alloy within it is molten or heated to a desired temperature, the conveyor system moves it down through a second support leg  418  to molten storage area  445 . The molten storage area  445  is insulated to help contain the heat of the heat storage containers  430 . These heated heat storage containers  430  are then moved from the heat storage area by the conveyor system or another conveyor or similar transporting system to a heat engine application  450  that usefully employs the heat energy. After being used and cooled, the heat storage containers  430  are transported back to the solidified storage and return area  440  for recycling and reheating. 
       FIG. 6  shows more details on the embodiment of the tertiary reflector, secondary mirror, and conveyor system. The transfer tube  505  serves as a support for the remaining structural elements. The tertiary reflector  515  reflects solar energy from the combination insulating lid and secondary reflector  520 . The combination insulating lid and secondary reflector  520  includes a mechanism to automatically close over the tertiary reflector  515  when either the solar energy level falls below a certain level or the temperature cools to a specified point and will reopen once the solar energy level increases. A conveyor system  525  rotates heat storage containers  530  into and out of the solar collection point at the top of the conveyor system. The conveyor system control system includes a temperature sensitive control that activates and rotates heat storage containers  530  when the temperature reaches a specified point. 
       FIG. 7  shows the embodiment of  FIG. 6  with the heat collection point closed. The combination insulating lid and secondary reflector  605  has been lowered to stop heat loss. The combination insulating lid and secondary reflector  605  operates to lower onto the tertiary reflector  610  along the supporting brackets  615 . The mechanism for lowering the tertiary reflector  610  can be located within the top of the supporting bracket  617 , within the combination insulating lid and secondary reflector  605 , or within the transfer tub  620 . However, a sensor must be located proximate to the heat storage container that is either sensitive to sunlight intensity or temperature. 
       FIG. 8  shows an embodiment for a heat storage container. The heat storage container  705  includes a pair of external integral moving lugs  710  that lock into the conveyor system. In this embodiment, the container has an outer shell  720  composed of stainless steel or a copper-based alloy. This outer shell must be made from a material with a higher melting point than the internal alloy mixture, and, although other metals may be used for the outer shell, stainless steel or a copper-based alloy are preferred. Other potential metals include titanium or titanium alloys, plain steel, or even iron. The core of the container is composed of an aluminum alloy  730 . The aluminum alloy has a relatively high heat of fusion so that the device can absorb or release a large amount of heat within a narrow temperature range. 
     This embodiment of the heat storage container  705  also requires a low-pressure gas void area to compensate for the thermal expansion of the aluminum alloy within the container during heating. Alternatively, there could be a vacuum void space within the container  705  to compensate for the thermal expansion. The size of the heat storage container  705  is variable and dependent on the overall size of the solar installation and the power demands of the application, but it is envisioned that the heat storage container will vary between having a volume of 250 ml (milliliters) to 3000 ml. 
       FIG. 9  show another embodiment for a heat storage container constructed from carbon fibers. The heat storage container  805  has an outer shell  810  formed from a double layer of carbon fiber. The inner core  820  is composed of aluminum or an aluminum alloy. The heat storage container  805  also uses reinforced, insulated eyelets  830  for grasping and moving the container  805 . 
     For this embodiment, there is no requirement for void space for thermal expansion, since the soft-sided structure composed of carbon fibers can expand and contract in response to the thermal expansion or contraction. For this type of container, the non-rigid carbon-fiber container would primarily rely on surface tension and small pore size to retain the molten core. 
     The carbon fiber offers advantages of high heat conduction, high melting point, and high strength per weight. A disadvantage is a need for operation in either an inert gas atmosphere environment or vacuum. However, it is envisioned that such a light-weight configuration may be useful in space-based applications such as lunar basing or orbital platforms. 
       FIG. 10  graphically shows how the system harnesses solar energy. A heat source  905 , the sun in these embodiments, impacts onto a solar mirror reflector system and heats the heat storage container  915  past the melting point of the aluminum alloy mixture in the core. In the preferred embodiment, the heat storage container  915  travels on a conveyor system and the next heat storage container transferred from solidified storage  950  replaces the original container  915  at the solar heat collection station. The original storage container  915  is then transported to an insulated energy storage area  920 . 
     In the energy storage area  920 , the original storage container  915  can be placed adjacent to secondary storage containers to generate high temperature heat loads  930  that are similar or identical to the primary heat storage container  915  except that they may contain alloy mixtures that have lower melting temperatures than the aluminum alloy mixture within the original (primary) container  915 . Another embodiment has the secondary storage containers containing the same aluminum alloy as the primary heat storage containers. 
     The secondary storage containers can be heated by the primary storage container  915  in order to produce a source of low-level heat for applications requiring such. An alternative embodiment heats secondary heat storage containers that have the same aluminum alloy comprising the core of the primary heat storage containers by placing them adjacent to superheated primary storage containers in the storage area until the containers reach the desired temperature level. 
     The energy storage area  920  can be located below ovens and can transmit heat into ceramic fire-brick just as traditional wood-fired ovens stored the heat of a fire in the masonry. Once the secondary storage containers have reached their respective intended temperatures, the primary storage container  915  or the secondary storage container can be removed from the heat storage area  920  to be used as a heat source for cooking or powering heat engines  935 , can be transferred to a generator application  940  to use to generate electricity  945 , or can be cooled to a point where they can be used for low temperature heat load applications  937 . 
     Alternatively, the primary storage container  915  can be moved directly from heat storage area  920  to utilize in high temperature heat load applications  930  or in a thermal engine  935  without any secondary storage containers. There is no absolute requirement for secondary storage containers within the system, and all energy applications may utilize the primary storage container  915  when at an acceptable temperature. 
     Over time, as the primary storage container  915  reaches lower temperatures, it can be used for low temperature heat load applications  937  such as absorption refrigeration, water heating, and drying garbage, waste, and biomass. Alternatively, low temperature heat, which is discharged from absorption units or heat-powered engines, can similarly be used to dry garbage, waste, and biomass, thereby producing a viable backup fuel as well as solving a disposal issue. 
     Furthermore, any secondary storage containers, which may contain alloy mixtures with lower melting temperatures, can be removed from the energy storage area and used in the applications requiring lower temperatures  937 , such as absorption refrigeration, absorption cooling, water heating, and extracting moisture from garbage, waste, and biomass. 
     Once cooled to point of solidification or are no longer useful for transferring stored energy for either high temperature applications  930  or low temperature applications  937 , the storage containers are transferred to solidified container storage  950 . This storage area stores storage containers  915  while not in use and are kept there until re-circulated through the system. Alternatively, there may not be any such storage area  950 , and storage containers are simply re-circulated once cooled. 
     For this application, other heat sources are possible, but regardless of the embodiment selected to heat the heat storage containers, the invention includes a backup heating system  925  in order to provide an alternative source of energy in case the primary source of energy is unavailable. The preferred embodiment of the backup heating system  925  is a fuel-based, high temperature heating system that can not only provide heat to the heat storage containers but also can be used as a direct source of heat. 
     While the invention has been particularly shown and described with respect to preferred embodiments, it will be readily understood that minor changes in the details of the invention may be made without departing from the spirit of the invention. Having described the invention,