Patent Publication Number: US-2021180830-A1

Title: Multi-focal point solar refraction heating

Description:
FIELD 
     The present disclosure is generally related to solar systems, and in particular, to solar systems used to heat materials. 
     BACKGROUND 
     There is a need to improve the energy efficiency associated with heating materials at industrial volumes. For example, at present in the United States (“US”), melting industrial materials entails a large quantity of energy with aluminum fabrication alone accounting for about 30% of that energy consumption. An even greater amount of energy is required when recycled steel is added. As such, major US industries, especially those industries related to metal recycling and stock material fabrication, occupy a major portion of the nation&#39;s total energy consumption. Therefore, for nearly every industry involved in the process of fabrication or recycling of existing materials, there is a need for high amounts of energy to melt materials, heat the materials, or for other key stage, or stages, of the process. 
     In general, the two major problems with conventional heating (e.g., known furnaces (also known as burners) utilize gas, induction, blast, and electric arc furnaces (“EAFs”)) are their dependence on limited and fossil fuels (e.g., coal, oil, and natural gas), as well as the inefficiencies in how they transfer the generated thermal energy to heat a material. It is appreciated by those of ordinary skill in the art that these types of furnaces have significant energy losses during the thermal energy transfer process (i.e., the process of heating the furnace and then utilizing that heat to melt or heat the material), which ultimately results in about 30 to 40% efficiency. This results generally because large amounts of energy input into a furnace does not directly translate to thermal energy. As an example, a blast furnace requires massive quantities of input energy to raise its temperature to its operating temperature. In aluminum melting, for example, only about 40% of the energy utilized by the furnace goes to actually melting the aluminum. 
     This problem is also similar for furnaces utilizing induction melting, which is done typically open to air. Electrical resistance furnaces (“ERTs”) that utilize the principle of indirect heating are capable of utilizing about 40% of their input energy for melting but in practice are only typically about 26% efficient because ERT furnaces typically experience other energy losses that include heating the air and then losing hot air through ventilation conduction to the insulating liner of the furnace and losses of energy when opening the ERT furnace. As a result, EAF furnaces require large quantities of electrical power and can have adverse environmental effects. Additionally, in many EAF furnaces, additional gas burners are typically utilized to assist in heating scrap metal to a temperature where the metal conducts electricity efficiently so as to allow the EAF furnace to run properly. Moreover, another major issue with these types of furnaces is the large carbon cost of the process due to the amount of carbon dioxide output by these systems. Unfortunately, their continued use is largely due to the relatively cheap cost of current sources of fuel. 
     Known uses of solar energy are not capable of addressing or solving these problems because known solar technologies are limited in their capacity, window of operation, and overall efficiency when capturing solar energy and transferring it into a usable fashion. Specifically, known solar systems have a number of inefficiencies in how they utilize solar energy to either heat an object or generate electricity. These solar cells placed on solar panels utilize photovoltaic cells to convert solar energy impinging on the solar cell into electricity. Common modernly used crystalline silicon solar cells output on average about 18% energy conversion due to losses of heat and the electricity transfer within the solar cells. 
     In addition to solar cells, modern solar systems also include systems that heat objects, such as water pipes for example, that transfer the resulting heat energy to other objects for heating those objects or generating electricity through movement of, for example, water through the pipes to a turbine. Moreover, another problem with solar energy is that it is not concentrated enough in any given area to use on an industrial scale or it requires a system in place to utilize the energy in a process which converts it to useable electricity. 
     Attempts to solve these problems have included using solar reflector systems to attempt to reflect and focus energy into a small area that can either generate power with a solar cell, heat water to generate electricity through a turbine, or heat a small crucible containing some material in a small furnace. However, even with the use of reflectors, the resulting systems still do not have high efficiency. Systems that utilize solar cells still only have limited efficiency (e.g., 18% efficiency). Systems that heat water still have the same thermal loses as the non-reflector solar heating systems. Additionally, furnaces lose energy from having to heat a crucible. Moreover, all of these solar reflector systems lose energy from transferring energy to additional components in the system and from reflection angle losses. Furthermore, some of these systems are stationary in a way that does not allow them to follow the Sun and, therefore, limits the amount of time that they can operate. 
     As such, there is a need for a solar energy capture system that is capable of producing a sufficient amount of energy for use in modern industrial processes that include heating or melting of industrial materials. 
     SUMMARY 
     In one example, a solar heating system includes a container configured to enclose contents, and a solar refraction device comprising a lens array assembly having a plurality of lens array sub-assemblies. The lens array assembly is configured to refract solar energy impinging on the lens array assembly to focus refracted solar energy at a plurality of focal points. Each focal point corresponds to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. The focal points are positioned to heat the contents enclosed within the container. In embodiments, the container is in a closed configuration. In another embodiment, the container encloses contents that are in another enclosed container. 
     The use of the phrase “in a closed configuration” hereinafter refers to the container that is being heated being partially or fully closed itself, or the container being open, partially closed or closed and the contents inside being enclosed in another container, object, housing or the like. 
     Another example provides a method for heating a container enclosing contents using a solar refraction device, wherein the container itself is either closed, (e.g., partially closed or fully closed) or wherein the contents of the container are enclosed in another container, housing, object or the like. The method includes refracting solar energy impinging on a lens array assembly of the solar refraction device, the lens array assembly having a plurality of lens array sub-assemblies. The method includes focusing the refracted solar energy at a plurality of focal points to heat the contents enclosed within the container. Each focal point corresponds to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. 
     In another example, a solar heating system includes an enclosed pipe, and a solar refraction device. The solar refraction device comprises a lens array assembly having a plurality of lens array sub-assemblies. The lens array assembly is configured to refract solar energy impinging on the lens array assembly to focus refracted solar energy at a plurality of focal points to heat a fluid enclosed in the pipe. Each focal point corresponds to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective back-view of an example of an implementation of a lens array assembly of a solar refraction device in accordance with the present disclosure. 
         FIG. 2  is a back-view of the lens array assembly shown in  FIG. 1  in accordance with the present disclosure. 
         FIG. 3  is a perspective back-view of an example of an implementation of a lens array sub-assembly of the lens array assembly shown in  FIGS. 1 and 2  in accordance with the present disclosure. 
         FIG. 4  is a perspective back-view of an example of an implementation of a single column array of lens panes of the lens array sub-assembly shown in  FIGS. 1, 2, and 3  in accordance with the present disclosure. 
         FIG. 5A  is a system view of an example of implementation of a refracting convex lens. 
         FIG. 5B  is a system view of the single column array of lens panes shown in  FIG. 4  in accordance with the present disclosure. 
         FIG. 6  is a perspective side-view of the lens array sub-assembly shown in  FIG. 3  in accordance with the present disclosure. 
         FIG. 7  is a perspective back-view of another example of an implementation of a lens array assembly of the solar refraction device and a heating container in accordance with the present disclosure. 
         FIG. 8  is a system view of the solar refraction device shown in  FIG. 7  in accordance with the present invention. 
         FIG. 9  is a perspective back-view of a plurality of solar refraction devices, as shown in  FIGS. 7 and 8 , utilized to heat or melt a material in accordance with the present disclosure. 
         FIG. 10  is a flowchart of an example of an implementation of a method performed by the solar refraction device shown in  FIGS. 1-9  in accordance with the present disclosure. 
         FIG. 11  is a flowchart of an example of an implementation of a method performed in fabricating the solar refraction device in accordance with the present disclosure. 
         FIG. 12  is a system diagram of an example of an implementation of the solar refraction device utilized for powering a turbine in accordance with the present disclosure. 
         FIG. 13  shows an example system  1300  including a solar refraction device utilized for heating the contents of a pipe. 
         FIG. 14  shows an example solar refraction device forming a canopy, and a plurality of reflectors to reflect light that passes through the solar refraction device. 
         FIG. 15  shows a schematic depiction of an example processing system that incorporates one or more solar refraction devices. 
     
    
    
     DETAILED DESCRIPTION 
     A solar refraction device (SRD) disclosed herein comprises a lens array assembly having a plurality of lens array sub-assemblies. The lens array assembly is configured to refract solar energy impinging on the lens array assembly to focus refracted solar energy at a plurality of focal points. Each focal point corresponds to a corresponding lens array sub-assembly of the lens array assembly. The plurality of focal points of the SRD can be positioned to heat objects using the refracted solar energy. The act of heating an object includes increasing its temperature and/or changing its phase in various examples. Objects heated by an SRD can include materials in various forms as well as containers that partially or fully enclose the materials. 
     In one example, an SRD is provided for heating materials in a closed container using diffuse solar energy that impinges on an outside surface of the SRD and is refracted through the SRD. The SRD includes a lens array assembly and a plurality of lens panes attached to the lens array assembly. The lens array assembly includes an outside surface corresponding to the outside surface of the SRD, an inside surface, and a plurality of lens array sub-assemblies. A sub-plurality of lens panes of the plurality of lens panes are attached to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. In an example, each lens array sub-assembly has a convex shape and has a focal length corresponding to the lens array sub-assembly which results in the lens array assembly having a plurality of focal lengths. 
     As an example of operation in accordance with the present disclosure, the SRD is configured to perform a method that includes refracting impinging solar energy (i.e., the solar energy that directly strikes and/or illuminates the SRD which may diffuse (i.e., spread) along an outer surface of the SRD) on the SRD through the lens array assembly having the plurality of lens array sub-assemblies. The refracted solar energy is then focused onto a plurality of focal points, where each focal point corresponds to a lens array sub-assembly of the plurality of lens array sub-assemblies. A heating area is defined by the plurality of focal points with respect to an object to be heated. For example, the heating area can be defined upon an external surface of materials to be heated or upon an external surface of a container that encloses materials to be heated. The object is then heated at the heating area utilizing the focused refracted solar energy. 
     Also disclosed is a method for fabricating the SRD in accordance with the present disclosure. The method includes determining the type and amount of heat needed to provide a temperature increase and/or phase change with respect to one or more materials and determining an amount of energy needed provide that amount of heat to the materials. An array size of a lens array assembly is then determined for producing the previously determined amount of energy, where the lens array assembly is configured to refract solar light impinging on the lens array assembly to the materials and/or a container holding the materials. The method then includes determining a focal length of the lens array assembly, assembling a support frame to support the lens array assembly, and assembling the lens array assembly. 
     In this disclosure, materials heated by an SRD can include any type of material or combination of materials in solid, liquid, and/or gas forms. While liquids and gases are examples of fluids, such materials can include granulated solids that can be conveyed and/or mixed in a manner similar to a fluid. Examples of materials that can be heated include working fluids (e.g., water within heat exchangers, heat engines, vapor cycles, and other thermodynamic systems), industrial materials, such as metallic industrial materials including aluminum, steel, iron or other metals or alloys, non-metallic industrial materials such as plastics or other recyclable non-metals, chemicals, such as chemical reactants and chemical products (e.g., in a chemical processing system), foods, seeds, soil, crushed stone, sand, animal waste, compost, lumber, and other forms of organic matter. 
     In  FIG. 1 , a perspective back-view of an example of an implementation of a lens array assembly  100  of an SRD  102  is shown in accordance with the present disclosure. SRD  102  includes the lens array assembly  100  and a plurality of lens panes  104  attached to the lens array assembly  100 . In this example, the lens array assembly  100  can include a support frame  106  constructed of a rigid material such as, for example, a metal such as steel or aluminum or other rigid non-metallic materials (e.g., wood or composites). The support frame  106  can include a plurality of openings that are configured to accept the plurality of lens panes  104 , which are each configured to be attached to the lens array assembly  100 . The support frame  106  is constructed of a rigid material that is strong enough to support the weight of, and stresses caused by, the plurality of lens panes  104  placed within the plurality of opening in the support frame  106  and capable of withstanding prolonged exposure in the environment to things such as, for example, electromagnetic radiation, thermal heat, and ultraviolent radiation without significantly degrading or warping. The lens array assembly  100  includes an outside surface  108  that also corresponds to the outside surface of SRD  102 , an inside surface (not shown), and a plurality of lens array sub-assemblies. In at least some examples, each lens array sub-assembly is a discrete panel of the lens array assembly  100 . However, two or more lens array sub-assemblies can be integrated into a common panel in another example. 
     In this example, the lens array assembly  100  is shown having nine (9) lens array sub-assemblies  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126 . Each lens array sub-assembly is shown having a sub-plurality of lens panes (from the total plurality of lens panes  104 ) attached to the corresponding lens array sub-assembly. As an example, part of a support structure  128  is also shown attached to one side of the lens array assembly  100 . The support structure  128  can be attached to the support frame  106  in a way that allows the support structure  128  to maintain the lens array assembly  100  at a predetermined distance from an object to be heated (e.g., a heating container or materials contained therein) where the predetermined distance is a distance that is based on the multiple focal lengths of the lens array assembly  100  (described in more detail later). The support structure  128  can be connected to, or part of, a solar tracker (not shown), where the solar tracker is configured to move the support structure  128  (and the as the lens array assembly  100 ) in a manner that maintains a high amount of solar energy being refracted through SRD  102  and focused at a heating area. In this disclosure, a “high” amount of solar energy is considered enough solar energy for SRD  102  to operate according to the present description. Similar to the support frame  106 , the support structure  128  can be constructed of a rigid material that is strong enough to support the weight of, and stresses caused by, the lens array assembly  100 . Support frame  106  can include metallic and non-metallic rigid materials. Furthermore, in this example, the lens array assembly  100  is shown to have a three-dimensional convex shape with each corresponding lens array sub-assemblies  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126  also being convex. In an example, the convex shape is approximately parabolic along the x-axis  130  and z-axis  132  and also along the y-axis  134  and z-axis  132 . In an example of operation, SRD  102  refracts diffuse solar energy  136  (i.e., the impinging solar energy) that impinges on the outside surface  108  (of both SRD  102  and lens array assembly  100 ) through SRD  102  resulting in a focused beam of refracted solar energy  138  that is focused in a direction along the z-axis  132  away from the inside surface of the lens array assembly  100 . 
     In this example, it is appreciated by those of ordinary skill in the art that only nine (9) lens array sub-assemblies  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126  have been shown in  FIG. 1  for purpose of illustration. However, the lens array assembly  100  can include more or less lens array sub-assemblies based on design and application of SRD  102 . As will be described later, in general each lens array sub-assembly will produce a corresponding focused beam of refracted solar energy that will have a focal length that corresponds to the specific lens array sub-assembly. The resulting focal lengths from the different lens array sub-assemblies can be different from each other so that the combined focused beams of refracted solar energy (for each lens array sub-assembly) combines to form the focused beam of refracted solar energy  138  that produces a heating area (described later) that is located at a distance from the SRD. In at least some examples, this heating area is distributed over a region of an object to heated, rather than being focused at a same location. 
     From the detail in  FIG. 1 , in this example, SRD  102  is shown to have an octagon two-dimensional convex shaped lens array assembly  100 . Additionally, the lens array assembly  100  is shown to have five (5) rectangular shaped two-dimensional convex lens array sub-assemblies  110 ,  112 ,  114 ,  116 , and  118  and four (4) triangular shaped two-dimensional convex lens array sub-assemblies  120 ,  122 ,  124 , and  126 . Moreover, each rectangular shaped two-dimensional convex lens array sub-assemblies  110 ,  112 ,  114 ,  116 , and  118  is shown to have 8 by 8 (i.e., 64) lens panes (or plurality of openings for 64 lens panes) and each triangular shaped two-dimensional convex lens array sub-assemblies  120 ,  122 ,  124 , and  126  is shown to have 28 lens panes (or plurality of openings for 28 lens panes) and eight (8) half-sized lens panes (or plurality of openings for 8 half sized lens panes). This results in SRD  102  having, in this example, a total of 432 lens panes and 32 half sized lens panes. Each of the lens panes of the plurality of lens panes  104  can be flat lens panes approximating a parabolic shape in the corresponding lens array sub-assembly based on the size and number of the discrete flat lens panes in the lens array sub-assembly or actual convex shaped lens panes. Furthermore, each lens pane can be made from glass, acrylic, or other suitable material. Moreover, each lens pane can be a flat or sloped lens pane or a Fresnel lens such that SRD  102  can be assembled from a combination of flat lens panes, sloped panes, and Fresnel lenses. In general, the lens panes can be removable and interchangeable within the lens array assembly  100 . Additionally, in order to make SRD  102  more dynamic, individual controls (not shown) can be installed in sections of the lens array assembly  100  or each opening that is configured to receive a lens pane in the lens array assembly  100  such that the controls are able to adjust the position of the individual panes to adjust the focus of SRD  102 . Again, the octagon two-dimensional convex shape of the lens array assembly  100  is an example for illustration purposes and can be a different shape based on the design of the lens array assembly  100 .  FIGS. 13 and 14 , for example, depict SRDs having different shapes from SRD  102 . 
     Turning to  FIG. 2 , a back-view of the lens array assembly  100 , shown in  FIG. 1  along viewing plane A-A′  140 , is shown in accordance with the present disclosure.  FIG. 2  illustrates the relationship of the plurality of sub-assemblies  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126  and plurality of lens panes  104  in relationship with the lens array assembly  100 . As described earlier, in this example, the lens array assembly  100  has an octagon shape and includes five rectangular shaped lens array sub-assemblies  110 ,  112 ,  114 ,  116 , and  118 , respectively, and four triangular shaped lens sub-assemblies  120 ,  122 ,  124 , and  126 , respectively. In this example, as described earlier, the five rectangular shaped lens array sub-assemblies  110 ,  112 ,  114 ,  116 , and  118  include 64 lens panes designated by  200 ,  202 ,  204 ,  206 , and  208 , respectively. Similarly, the four triangular shaped lens array sub-assemblies  120 ,  122 ,  124 , and  126  include 28 lens panes designated by  210 ,  212 ,  214 , and  216 , respectively, and 8 partial sized lens panes  218 ,  220 ,  222 , and  224 , respectively. If the four triangular shaped lens array sub-assemblies  120 ,  122 ,  124 , and  126  are generally equivalent to half of a rectangular shaped lens array sub-assemblies, then the four triangular shaped lens array sub-assemblies  120 ,  122 ,  124 , and  126  act as the equivalent of two rectangular shaped lens array sub-assemblies. In this case, the lens array assembly  100  can be described as having a total of seven (7) rectangular shaped lens array sub-assemblies instead of nine (9). As a result, the SRD  100  would have a total of 448 lens panes attached to the lens array assembly  100 . 
     In general, the amount of energy produced by SRD  102  is directly related to the amount or intensity of solar energy incident upon the SRD, the location/positioning where the SRD will be utilized, and the array size of lens array assembly  100 . For example, the higher the concentration of sunlight, the higher the amount of energy that is produced by SRD  102  for a given size of the lens array assembly  100 . Specifically, according to the National Renewable Energy Laboratory (“NREL”) average data from 1998 to 2009, areas within the United States such as Arizona and parts of California, Nevada, New Mexico, Colorado, and Hawaii receive as an annual average over 7.5 Kilowatt hours (“KWh”) per square meter (m2) per day of concentrated solar power (“CSP”) that is available for use by solar systems. 
     Generally, the amount of solar energy which falls on the Earth in any a calendar year dwarfs the total energy output of all the world&#39;s fossil fuels used in world&#39;s industries. For example, the State of Kentucky receives about 3.75 kW/m2 of solar energy per day from the Sun and higher energy areas, such as Hawaii, receive about 5.75 kW/m2 of solar energy per day. Only a fraction of these totals are used for creating useable energy with the current solar cells because, current commonly used solar cells generally only reach about 18% energy conversion due to losses of heat, reflection angle, and electricity transfer. 
     As such, utilizing Hawaii as an example for melting aluminum, a 6 foot by 6 foot (i.e., an area of about 4 m2) lens array sub-assembly  110 ,  112 ,  114 ,  116 , and  118  would be able to focus about 4 KWh of solar energy such that lens array assembly  100  would be able to focus at least 28 KWh of solar energy taking into account the five (5) rectangular shaped lens array sub-assemblies  110 ,  112 ,  114 ,  116 , and  118  and four (4) triangular shaped lens array sub-assemblies  120 ,  122 ,  124 , and  126 . Assuming, 85% efficiency in this example, SRD  102  would be capable of melting about 74 pounds of aluminum per hour. 
     In  FIG. 3 , a perspective back-view of an example of an implementation of a lens array sub-assembly  300  of the lens array assembly  100  (shown in  FIGS. 1 and 2 ) is shown in accordance with the present disclosure. The lens array sub-assembly  300  is show including a support frame  302  and approximately 36 lens panes  304  organized in six (6) rows and six (6) columns. The reason for only showing six (6) columns and rows in this example is for convenience of illustration since every lens pane  304  is being shown within a support frame of the lens array sub-assembly  300 . The support frame is shown having a first side  306  and a second side  308 . In this example, the convex curvature of the first side  306  of the support frame is shown along the x-axis  310  and z-axis  312 . Similarly, the convex curvature of the second side  308  of the support frame is shown along the y-axis  314  and z-axis  312 . As described earlier, the convex curvature can be approximately parabolic for both the first and second sides  306  and  308  of the support frame. If approximately parabolic, the lens array assembly  100  will produce a more focused beam of refracted solar energy  138  because in general a parabola is a special curve that has the mathematical relationship where all points of the parabola are an equal distance away from both a fixed line (mathematically referred to as the directrix) and a fixed point (mathematically referred to as the focus of the parabola, which is not to be confused with other instances of the term focus utilized in the present disclosure in connection with light or refracted solar energy). 
     Additionally, in  FIG. 3 , the panes  304  of a first column  316  of panes  304  is shown receiving diffuse solar energy and focusing  318  it to a focal point  320 . More specifically, turning to  FIG. 4 , a perspective back-view of an example of an implementation of a single column array of lens panes  400  of the lens array sub-assembly shown  300  (shown in  FIG. 3 ) is shown in accordance with the present disclosure. In this example, the single column array of lens panes  400  includes six (6) lens panes  402 ,  404 ,  406 ,  408 ,  410 , and  412 . As an example of operation, the single column array of lens panes  400  is configured to receive a portion  414  of the diffuse solar energy  136  that impinges on the outside surface of the SRD and refract that portion  414  through the lens panes  402 ,  404 ,  406 ,  408 ,  410 , and  412  to produce a focused beam  416  of solar energy that is focused to focal point  418 . 
     To further explain this example, in  FIGS. 5A and 5B , system views of a continuous refracting convex lens  500  and of the single column array of lens panes  502  (shown in  FIG. 4  cut along plane B-B′  420 ) are shown along a center line  504 . In both examples, impinging diffuse solar energy  506  is refracted and focused  508  and  510  to focal points  512  and  514 , respectively. As a result, in operation, the discrete refracting convex lens created by the single column array of lens panes  502  focuses  510  the refracted solar energy to approximately the same focal point  514  as the focal point  512  of the continuous refracting convex lens  500 . 
     In  FIG. 6 , a perspective side-view of a lens array sub-assembly  600  (shown in  FIG. 3  as lens array sub-assembly  300 ) is shown in accordance with the present disclosure. In contrast to  FIG. 3 , in  FIG. 6 , an example of operation is shown where diffuse solar energy  602  impinges on an outside surface  604  of lens array sub-assembly  600  that includes a plurality of lens panes  606 . Each lens pane of the plurality of lens panes  606  then refracts a portion of the diffuse solar energy  602 . In this example, all of the refracted beams from the plurality of lens panes  606  are focused  608  into a focal point  610  that is utilized to heat an object (not shown). Within  FIG. 6 , the focal length  612  of the lens array sub-assembly  600  is shown as the distance between the focal point  610  and a centerline  614  of the lens array sub-assembly  600 . This focal length  612  is based on the design of the lens array sub-assembly  600 . Turning back to  FIGS. 1 and 2 , it is noted that there are multiple lens array sub-assemblies  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126  that each have their own corresponding focal length. Additionally, these multiple focal lengths can be equal or not equal to each other based on the design of the SRD for heating an object. By having different focal lengths or different focal points for each lens array sub-assembly  110 ,  112 ,  114 ,  116 ,  118 ,  120 ,  122 ,  124 , and  126 , the lens array assembly  100  focus the diffused solar energy over a region rather than an individual point. This allows SRD  102  to heat an object at a heating plane by distributing the heat of the focused solar energy over a region of the heating plane. If solar energy refracted by the SRD is overly focused rather than being distributed over a region, the refracted solar energy can damage or burn the object being heated, which can include the container or materials contained therein. 
     Expanding on this in  FIG. 7 , a perspective back-view of another example of an implementation of a lens array assembly  700  of the SRD  702  is shown in accordance with the present disclosure. In this example, the lens array assembly  700  is shown having five (5) rectangular shaped lens array sub-assemblies  704 ,  706 ,  708 ,  710 , and  712 , respectively. Additional triangular shaped lens array sub-assemblies can be added as described earlier, however, in this example only five (5) rectangular shaped lens array sub-assemblies  704 ,  706 ,  708 ,  710 , and  712  are shown for the purpose of illustration. In this example, the lens array assembly  700  is shown having five different focal lengths or focal points  714 ,  716 ,  718 ,  720 , and  722  for the individual lens array sub-assemblies  704 ,  706 ,  708 ,  710 , and  712 . The resulting focal points define a heating area  724  upon a closed heating container  726 . It will be understood that heating container  726  is merely one example of a closed container that can be used to heat materials. In the example of  FIG. 7 , heating area  724  is defined in size and shape by the plurality of focal points  714 ,  716 ,  718 ,  720 , and  722  so that the heating area is located upon an exterior surface of the container within a region bounded by the container, but is also sufficiently distributed to avoid excessive heating that can damage the container or its contents. 
     Additionally, shown in this example is a schematic representation of support structure  128  that can be used to support lens array assembly  700 . In this example, the heating area  724  is shown to be a predetermined distance  728  from the lens array assembly  700 . Specifically, the predetermined distance  728  is defined as the distance  728  between a centerline  730  of the plane of the heating area  724  and another centerline  732  of lens array assembly  700 . The predetermined distance  728  is generally related to the focal lengths of the individual lens array sub-assemblies  704 ,  706 ,  708 ,  710 , and  712  that produce respective focal points  714 ,  716 ,  718 ,  720 , and  722  that define heating area  724 . As a result, the predetermined distance  728  is based on the design of the lens array assembly  700 , because the focal lengths are based on the design of the lens array sub-assembly  700 . In an example, support structure  128  is configured to maintain this predetermined distance  728  between the lens array assembly  700  and heating area  724  located upon an exterior of heating container  726 . As such, since the type of material, thickness, position, and angle of the lens panes within each lens array sub-assemblies  704 ,  706 ,  708 ,  710 , and  712  determines the corresponding focal points  714 ,  716 ,  718 ,  720 , and  722 , it is appreciated that the type of material, thickness, position, and angle of the lens panes within each lens array sub-assemblies  704 ,  706 ,  708 ,  710 , and  712  can be designed or otherwise selected such that they produce the corresponding focal points  714 ,  716 ,  718 ,  720 , and  722  at the predetermined distance  728  and desired arrangement. 
     In  FIG. 8 , a system view of an SRD  800  is shown in accordance with the present disclosure. In this example, a centerline  802  is shown for equivalent lens  803  of plurality of lens panes of SRD  800 . SRD  800  is shown to have a focal length  804  that extends to a focal point  806  beyond an exterior surface of heating container  810  that faces SRD  800 . As an example of operation, the heating container  810  contains a material to be heated such as, for example, aluminum. The impinging diffuse solar energy  814  is refracted by the plurality of lens panes of the SRD  800  to form a plurality of refracted solar beams  816  (also known as rays). Since, an exterior surface of heating container  810  encloses the material contained therein, the focused refracted solar beams  816  cannot concentrate their combined energy at focal point  806  and instead impinge on the exterior surface of container  810  at a heating plane  820 . Since heating plane  820  is located between the SRD  800  and focal point  806 , the resulting heat generated by the focused refracted solar beams  816  is distributed over a heating area  822  that resides within heating plane  820 . In an example, heating area  822  is defined as a relatively small area compared to the size of SRD  800 . By properly designing or otherwise positioning SRD  800  relative to an object to be heated, heating area  822  receives the proper amount of energy from SRD  800  to heat the object (e.g., material  812  in this example) within suitable parameters. In this example, SRD  800  provides the greatest intensity of refracted solar energy along centerline  826 , with the refracted solar energy being more diffuse moving outwards from the centerline  826 . As such, the greatest intensity of heat energy provided by refracted solar energy within heating plane  820 , within this example, is at the intersection of heating plane  820  with centerline  826 . Intensity of the heat provided by the refracted solar radiation diminishes, in this example, as distance increases from centerline  826  within heating area  822 . As described earlier, the focal length  804  is related to the predetermined length  830  between centerline  802  of equivalent lens  803  to the heating container  810 , where the predetermined length  830  is the length from the centerline  802  to the heating plane  820 . 
     In some cases, an individual instance of SRD  800  is not sufficient to generate enough energy to heat an object to a desired state or to process a series of objects within a given time period. In these cases, multiple SRDs can be utilized together (e.g., in a chain) to increase the available heat energy or to increase a quantity of objects that can be heated within a given time period.  FIG. 9  shows an example in which a plurality of SRDs  900 ,  902 ,  904 , and  906  are utilized to heat material enclosed in a plurality of heating containers  910 ,  912 ,  914 , and  916 , respectively. In this example, SRDs  900 ,  902 ,  904 , and  906  direct refracted solar energy onto exterior surfaces of the heating containers to form respective heating areas  920 ,  922 ,  924 , and  926 . The multiple SRDs  900 ,  902 ,  904 , and  906  can be positioned by any known solar tracking system to collect the optimal quantity of solar light during the day. To maintain the optimal energy focusing of the SRDs  900 ,  902 ,  904 , and  906 , the heating containers  910 ,  912 ,  914 , and  916  can be moved from one SRD to the next via a track system  930 . In this example, the track system  902  is configured to input or extract a given heating container  910 ,  912 ,  914 , and  916  at any point during the heating process to remove melted or heated material and input unheated materials that are enclosed within unheated containers. 
     Turning to  FIG. 10 , a flowchart  1000  of an example method performed by or with respect to an SRD is shown in accordance with the present disclosure. The SRD of flowchart  1000  can refer to any of the example SRDs disclosed herein. In general, the method includes heating an object, such as a container that contains one or more materials, with solar energy refracted by the SRD. The container can be closed container that includes materials contained within the container, such as previously described with reference to  FIGS. 7 and 8 . 
     The method starts at  1002  by, in step  1003 , refracting solar energy impinging on the SRD through a lens array assembly having a plurality of lens array sub-assemblies and, in step  1004 , focusing the refracted solar energy onto a plurality of focal points. Each focal point of the plurality of focal points corresponds to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. In at least some examples, at least a portion of the refracted solar energy can be reflected at  1005 .  FIG. 14  depicts an example in which reflector are used to reflect some of the refracted solar energy provided by an SRD. 
     In at least some examples, each focal point can be spaced apart from each other focal point of the plurality of focal points to define a heating area. In these examples, the method at  1006  includes creating a heating area with respect to an object to be heated (e.g., upon an exterior surface of the heating container) utilizing the plurality of focal points as defined, at least in part, by their respective focal lengths. In step  1007 , the object is heated utilizing the focused refracted solar energy. For example, in step  1008 , contents of a container (e.g., containing one or more materials) are heated at the heating area utilizing the focused refracted solar energy. At  1010 , the method ends or returns to the start at  1002 . 
     In  FIG. 11 , a flowchart  1100  of an example method performed in fabricating an SRD is shown in accordance with the present disclosure. The method starting at  1102  includes determining, at  1104 , parameters of an object to be heated. For example, the method at  1104  can include determining a size, shape, mass, composition, reflectivity, specific heat, flow rate (e.g., in material flow applications) and initial conditions (e.g., temperature, pressure, phase, etc.) for materials to be heated. Where the object further includes a container that encloses materials are to be heated, the method at  1104  can include determining a size, shape, mass, composition, reflectivity, specific heat, and initial conditions for the container. 
     The method at  1106  includes determining an amount of energy needed to heat the object to a desired temperature and/or phase within a defined time period based on the parameters determined at  1104 . As an example, to melt aluminum, an SRD might need to provide approximately 30,000 watts of refracted solar energy to melt about 100 pounds of aluminum per hour. 
     The method at  1108  includes determining an array size for the lens array assembly for producing the previously determined amount of energy for a given density of solar energy impinging on the lens array assembly. As previously discussed, the lens array assembly is configured to refract solar light impinging on the lens array assembly to the object being heated. As an example, in Hawaii the Sun produces about 1,000 watts per square meter so the lens array assembly needs to be approximately 30 m2 (i.e., about 6 meters by 6 meters). 
     The method at  1110  determines a focal length of the lens array assembly based on the geometry of the lens array assembly. The method at  1112  includes assembling the lens array assembly. The method then ends at  1114 . In this example, assembling the lens array assembly can include assembling a plurality of lens array sub-assemblies and attaching the plurality of lens array sub-assemblies to form the lens array assembly, where each lens array sub-assembly has a corresponding focal length. As previously discussed, each lens array sub-assembly has a convex shape in at least some examples. Assembling the lens array assembly includes attaching a plurality of lens panes to each plurality of lens array sub-assemblies. In one example, the lens panes include Fresnel lenses. Moreover, assembling the lens array assembly also includes a first lens array sub-assembly with a different corresponding focal length than a second focal length corresponding to a second lens array sub-assembly of the lens array assembly. However, some or all of the lens array sub-assemblies of an SRD can have the same focal length in another example. 
     It will be appreciated by those of ordinary skill in the art that the examples of an SRD disclosed herein can be used to heat materials contained within an enclosure to increase the temperature of the materials or to change the phase of the materials (e.g., from solid to liquid or from liquid to vapor). For example, an SRD can be used to heat a fluid contained within a container such as an enclosed pipe, pressure vessel or other enclosed vessel, furnace, reactor, etc. The container can form part of a chemical processing system, electro-chemical processing system, oil refinery, food processing system, power plant, industrial boiler, physical plant (e.g., radiative heating), heating system (e.g., HVAC), sanitation system, etc. In at least some examples, the fluid can include an intermediate working fluid (e.g., water) that is used to transfer heat to a heat sink. In examples where an intermediate working fluid is used, this intermediate working fluid can provide power to machinery (e.g., turbines) or heat to another system or material (e.g., chemicals, foods, fossil fuels, etc.). 
     Turning to  FIG. 12 , a system diagram of an example of an implementation of the SRD  1200  utilized for powering a turbine  1202  is shown in accordance with the present disclosure. The turbine  1202  can include a plurality of turbine blades (also known as vanes)  1204  and a shaft  1206 . In this example, the turbine  1202  is connected to a heating container  1208  via at least an inflow tubular pipe  1210  and outflow tubular pipe  1212 . The heating container  1208  includes a plurality of heating pipes  1214  within the heating container  1208  that are configured to be heated by the SRD  1200 . The heating pipes  1214  can be filled with a fluid such as, for example, a gas (such as, for example, air), steam, water, or other heatable fluid that is capable of being heated in the heating container  1208  and passed to the turbine  1202 . Turbine  1202  is a rotary machine that extracts energy from the resulting fluid flow and converts it into useful work energy that rotates  1216  shaft  1206 . In an example of operation, the SRD  1200  receives solar energy and focuses at  1218  refracted solar energy towards heating pipes  1214  of heating container  1208 . As previously discussed, multiple focal points  1220 ,  1222 ,  1224 , and  1226  can be focused at  1218  towards the heating container  1208  to define a heating area  1230  with respect to heating container  1208 . The fluid in the heating pipes  1214  is then heated up and the heated fluid is passed to the turbine  1202  via inflow tubular pipe  1210  in the direction of  1232 . The heated fluid turns the turbine blades  1204  resulting in the shaft  1206  rotating  1216  along its axis. The exhausted fluid is returned to the heating container  1208  via the outflow tubular pipe  1212  in the direction  1234 . It is appreciated by those of ordinary skill in the art that other industrial heating examples can be implemented by utilizing the SRD  1200  as a heating device for other materials. 
       FIG. 13  shows an example solar heating system  1300  including an SRD  1310  and a pipe segment  1320  that can be heated by solar energy refracted by SRD  1310 . SRD  1310  can incorporate any of the SRD configurations disclosed herein, including a lens assembly having a plurality of lens array sub-assemblies in which each lens array sub-assembly provides a corresponding focal point of refracted solar energy that is positioned to heat the contents enclosed within pipe segment  1320 . Pipe segment  1320  is one example of a container for contents to be heated by an SRD. Within the context of a container that encloses contents, the focal points of refracted solar energy provided by SRD  1310  can be positioned at a surface of the container (e.g., an exterior of pipe segments  1320 ). 
     In this example, pipe segment  1320  forms part of a pipe system  1322  represented schematically in  FIG. 13  that contains a flow of contents. For example, pipe system  1322  can form a closed loop containing a material (e.g., a fluid such as a liquid or gas, or granulated solids). Accordingly, pipe system  1322  is one example of an enclosed container that can be heated by an SRD. Pipe system  1322  can be connected to one or more system components  1330  represented schematically in  FIG. 13  such that pipe segment  1320  is in fluid communication with the system components. In an example, pipe system  1322  in combination with system components  1330  forms a closed loop containing a material (e.g., a fluid or granulated solids). Accordingly, pipe system  1322  in combination with system components  1330  is another example of an enclosed container that can be heated by an SRD. 
     System components  1330  can include one or more mechanical conveyance machines (e.g., a pump or auger conveyor) to convey or circulate a material within the pipe system  1322  in a particular flow direction. System components  1330  can include one or more heat sinks that extract heat from a material contained within pipe system  1322 . Examples of heat sinks include mechanical machines (e.g., turbines) that extract heat energy from a material and convert that heat energy into work, heat exchangers, or other materials to be heated. 
     In the example depicted in  FIG. 13 , SRD  1310  has a curved shape within a plane that is orthogonal to a longitudinal axis  1324  of pipe segment  1320 . Surface  1312  of SRD  1310  that faces pipe segment  1320  forms an interior of the curved shape. Thus, in this example, the shape of SRD  1310  is generally contoured to the shape of the object to be heated by the SRD, which in this case takes the form of segment  1320  having a round cross-section. System  1300  further includes a support structure  1340  in this example. For example, support structure  1340  supports SRD  1310  relative to pipe segment  1320 . However, pipe segment  1320  and SRD  1310  can be separately supported in other examples. It will be understood that SRD  1310  can have other suitable shapes and configurations from the example depicted in  FIG. 13  to heat enclosed containers, including pipe systems that convey materials along a flow direction. 
       FIG. 14  shows an example solar heating system  1400  including an SRD  1410  and one or more reflectors  1420  (e.g., mirrors) positioned to reflect at least a portion of refracted solar energy  1412  received from the SRD toward an object  1430 . SRD  1410  can incorporate any of the SRD configurations disclosed herein, including a lens assembly having a plurality of lens array sub-assemblies in which each lens array sub-assembly provides a corresponding focal point of refracted solar energy that is positioned to heat object  1430 . In the example depicted in  FIG. 14 , SRD  1410  forms a canopy and has a curved shape. Thus, SRD  1410  can shield object  1430  from precipitation or other contaminants in addition to providing refracted solar energy for heating. Object  1430  can refer to any of the containers or materials disclosed herein that is heated by an SRD. 
     One example of reflectors  1420  is depicted at  1422  reflecting a first portion  1440  of refracted solar energy  1412  received from SRD  1410  toward object  1430 . For example, this first portion  1440  of refracted solar energy  1412  can be focused at a first focal point that is positioned to heat object  1430  at a first location  1450 .  FIG. 14  further depicts a second portion  1442  of refracted solar energy  1412  received from SRD  1410  being focused at a second focal point that is positioned to heat object  1430  at a second location  1452 . In this example, the second portion  1442  of the refracted solar energy is not reflected by a reflector. Reflectors  1420  can be used to reflect different portions of the refracted solar energy received from SRD  1410  to the same focal point or to different focal points that are spaced apart from each other. A second example of reflectors  1420  is depicted at  1424  reflecting a third portion  1444  of refracted solar energy  1412  received from SRD  1410  toward object  1430 . In this example, the third portion  1444  of the refracted solar energy is focused at a third focal point that is positioned to heat object  1403  at a third location  1454  that is spaced apart from locations  1450  and  1452 . 
     Reflectors, such as example reflectors  1420 , can be used to direct refracted solar energy to different regions of an object, including regions that reside outside of the optical path of the refracted solar energy emitted from surfaces of the SRD. For example, as depicted in  FIG. 14 , reflectors can be used to direct refracted solar energy to an underside or side regions of object  1430 . In these examples, reflectors can be arranged around or partially beneath the object being heated. Reflectors  1420  can be flat or curved, including reflectors that have a planar reflective surface, a convex reflective surface (e.g., semi-circular or parabolic as viewed in cross-section), or a concave reflective surface (e.g., semi-circular or parabolic as viewed in cross-section). 
     The use of reflectors with an SRD has the potential to increase heating efficiency of the solar heating system by using refracted solar energy that would otherwise not come into contact with the object. For example, reflectors can be configured to accommodate variations in an angle of the refracted solar energy as the sun transits the sky. Additionally or alternatively, the use of reflectors with an SRD has the potential to more evenly heat an object over its various surfaces. Reflectors can be positioned at fixed positions and orientations relative to an SRD or to an object to be heated by the SRD. However, in at least some examples, reflectors are moveable (e.g., by electromechanical actuators) in one or more degrees of freedom (e.g., translation and/or rotation relative to one, two, or three axes) to enable the reflectors to accommodate a variety of lighting conditions, heating scenarios, and object configurations. 
       FIG. 15  shows a processing system  1500  that incorporates one or more SRDs  1540 ,  1542 ,  1544 , etc. at various stages of a manufacturing process. The SRDs in this example include any of the example SRDs disclosed herein. As one example, solar energy refracted by SRD  1540  is used to heat a first material  1510  that is then provided as a first input to a set of one or more processing stages  1520 . Material  1510  can be heated by SRD  1540  within an enclosed container or other container, for example. As depicted in  FIG. 15 , additional materials (e.g., material  1512 ) can be provided as additional inputs to the one or more of processing stages  1520  where materials  1510 ,  1512 , etc. are combined to form a product  1530  as an output of the processing system. Solar energy refracted by SRD  1542  can be used to heat any combination of materials during the one or more processing stages  1520 . Such materials can be heated within an enclosed container or other material, for example. Solar energy refracted by SRD  1544  can be used to heat product  1530  that is output from the one or more processing stages  1520 . Product  1530  can also be heated within an enclosed container or other container, for example. Further, solar energy can be used to heat any transport lines or tubes between the starting material container(s), processing stage(s), and product container(s). Processing system  1500  may represent any suitable type of processing systems. Examples include, but are not limited to, chemical processing systems (e.g. a refinery or other chemical plant), food processing systems (e.g. a food product manufacturing facility), and waste processing systems. 
     Examples of the subject matter of the present disclosure are described in the following enumerated paragraphs. 
     A1. A solar heating system, comprising: a container configured to enclose contents within the container in a closed configuration; and a solar refraction device comprising a lens array assembly having a plurality of lens array sub-assemblies, the lens array assembly configured to refract solar energy impinging on the lens array assembly to focus refracted solar energy at a plurality of focal points positioned to heat the contents enclosed within the container in the closed configuration, each of the plurality of focal points corresponding to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. 
     A2. The solar heating system of paragraph A1, wherein the container comprises an enclosed pipe configured to contain a fluid as the contents. 
     A3. The solar heating system of paragraph A2, wherein the enclosed pipe is configured to contain a gas as the contents. 
     A4. The solar heating system of paragraph A2, wherein the enclosed pipe is configured to contain a liquid as the contents. 
     A5. The solar heating system of paragraph A2, wherein the enclosed pipe is configured to contain a flow of the contents including one or more of a chemical reactant and a chemical product in a chemical processing system. 
     A6. The solar heating system of paragraph A2, wherein the enclosed pipe is a part of a sanitation system. 
     A7. The solar heating system of paragraph A2, wherein the enclosed pipe is a part of a food processing system. 
     A8. The solar heating system of any of paragraphs A1-A7, wherein the plurality of focal points are positioned at a surface of the container. 
     A9. The solar heating system of any of paragraphs A1-A8, further comprising one or more reflectors positioned to reflect at least a portion of the refracted solar energy toward the container. 
     A10. The solar heating system of any of paragraphs A1, A8 or A9, wherein the container comprises an enclosed vessel. 
     A11. The solar heating system of any of paragraphs A1, A8, A9, or A10, wherein the container comprises a furnace. 
     B1. A method for heating a container enclosing contents within the container in a closed configuration using a solar refraction device, the method comprising: refracting solar energy impinging on a lens array assembly of the solar refraction device, the lens array assembly having a plurality of lens array sub-assemblies; and focusing the refracted solar energy at a plurality of focal points upon an exterior surface of the container to heat the contents enclosed in the container, each focal point corresponding to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. 
     B2. The method of paragraph B1, wherein the container comprises an enclosed pipe, and the contents comprise a fluid. 
     B3. The method of any of paragraphs B1-B2, wherein the container is part of a chemical processing system. 
     B4. The method of any of paragraphs B1-B3, further comprising reflecting, via a reflector, at least some of the refracted solar energy toward the container. 
     C1. A solar heating system, comprising: an enclosed pipe enclosing contents therein in a closed configuration; and a solar refraction device comprising a lens array assembly having a plurality of lens array sub-assemblies, the lens array assembly configured to refract solar energy impinging on the lens array assembly to focus refracted solar energy at a plurality of focal points to heat a fluid enclosed in the pipe, each focal point of the plurality of focal points corresponding to a corresponding lens array sub-assembly of the plurality of lens array sub-assemblies. 
     C2. The system of paragraph C1, wherein the enclosed pipe is in fluid communication with a turbine. 
     C3. The system of paragraph C2, wherein the contents comprise a fluid. 
     C4. The system of any of paragraphs C1-3, wherein the enclosed pipe is a part of a chemical processing plant. 
     C5. The system of any of paragraphs C1-C4, wherein the solar refraction device forms a canopy having a curved shape. 
     It will be understood that various aspects or details of the invention may be changed without departing from the scope of the invention. It is not exhaustive and does not limit the claimed inventions to the precise form disclosed. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention.