Patent Publication Number: US-8112996-B2

Title: Systems and methods for collecting solar energy for conversion to electrical energy with multiple thermodynamic engines and piezoelectric generators

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present non-provisional patent application is a continuation-in-part of co-pending U.S. patent application Ser. No. 12/212,249, filed Sep. 17, 2008, and entitled “SYSTEMS AND METHODS FOR COLLECTING SOLAR ENERGY FOR CONVERSION TO ELECTRICAL ENERGY,” and co-pending U.S. patent application Ser. No. 12/212,408, filed Sep. 17, 2008, and entitled “APPARATUS FOR COLLECTING SOLAR ENERGY FOR CONVERSION TO ELECTRICAL ENERGY,” each of which claims priority to U.S. Provisional Patent Application Ser. No. 60/993,946, filed Sep. 17, 2007, entitled “METHOD AND APPARATUS FOR CONVERTING SOLAR ENERGY INTO ELECTRICAL ENERGY,” all of which are incorporated in full by reference herein. The present non-provisional patent application is also a continuation-in-part of U.S. patent application Ser. No. 12/355,390, filed Jan. 16, 2009 now U.S. Pat. No. 7,876,028, and entitled “SYSTEMS AND METHODS FOR COLLECTING SOLAR ENERGY FOR CONVERSION TO ELECTRICAL ENERGY WITH PIEZOELECTRIC GENERATORS” which claims priority to U.S. Provisional Patent Application Ser. No. 61/011,298, filed Jan. 16, 2008, entitled “METHOD AND APPARATUS FOR CONVERTING SOLAR ENERGY INTO ELECTRICAL ENERGY USING CLOSED-CYCLE THERMODYNAMIC ENGINES AND PIEZO-ELECTRIC GENERATORS.” Additionally, the present non-provisional patent application claims priority to U.S. Provisional Patent Application Ser. No. 61/063,508, filed Feb. 4, 2008, entitled “METHOD AND APPARATUS FOR CONVERTING SOLAR ENERGY INTO ELECTRICAL ENERGY USING MULTIPLE CLOSED-CYCLE THERMODYNAMIC ENGINE AND PIEZO-ELECTRIC GENERATORS,” and to U.S. Provisional Patent Application Ser. No. 61/066,371, filed Feb. 20, 2008, entitled “METHOD AND APPARATUS FOR CONVERTING ELECTROMAGNETIC ENERGY INTO ELECTRIC AND THERMAL ENERGY USING A CLOSED-CYCLE THERMODYNAMIC ENGINE AND ELECTRIC GENERATOR,” all of which are incorporated in full by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to solar-to-electrical energy conversion. More particularly, the present invention provides systems and methods for collecting and converting solar energy into electrical energy by using solar collectors with multiple closed-cycle thermodynamic engines and/or piezoelectric generators. 
     BACKGROUND OF THE INVENTION 
     Solar energy is one of the renewable energy sources that does not pollute, it is free, and available virtually everywhere in the world. For these reasons, over the years there have been many systems and methods that attempted to utilize solar energy and convert it into other usable forms of energy such as electricity. More recently, due to perceived shortages and higher prices of fossil fuels and due to pollution concerns, the interest has increased and the pace of development of technologies that utilize alternative energy sources (such as solar) has accelerated. 
     There are two main techniques developed to harvest solar energy. The first technique utilizes photovoltaic solar cells to directly convert solar energy into electricity. The photovoltaic solar cells have the advantage of small size, but are expensive to manufacture and the price per watt has leveled due to the high cost of the semiconductor substrate utilized to construct the photovoltaic solar cells. There are many types of designs and materials used to make photovoltaic solar cells which affect their cost and conversion efficiency. Current commercially available solar cells typically reach a starting efficiency around 18% which drops over time. The cells produce direct current (DC) that needs to be regulated, and for higher power applications typically the DC current also needs to be converted to AC current. 
     The second technique utilizes the heat (infrared radiation) associated with the solar energy. Assuming that the goal is to generate electrical energy, the solar radiation gets collected, concentrated, and utilized as a heat source for various systems that convert the heat into mechanical energy, which is then converted into electrical energy. Successful machines developed to convert heat into mechanical energy can be based on thermodynamic cycles. Mechanical energy produced by these machines is further converted into electrical energy by using rotating generators or linear generators. For example, in the case of a Stirling engine, heat (which can come from any heat source) is applied at one end of the engine and cooling is provided at a different location. The working fluid (gas), which is sealed inside the engine, goes through a cycle of heating (expansion) and cooling (contraction). The cycle forces a piston inside the engine to move and produce mechanical energy. When the heat source is solar, successful engine designs use an intermediate medium such as molten salt to more uniformly distribute the heat around the outside surface of the heating end of the engine. 
     With respect to the second technique, problems arise when the surface of the engine is exposed to large temperature gradients due to close proximity of the heat and cooling sources on the surface of the engine. For example, conventional engines can see extreme temperatures from day to night and along the length of the engine body with temperatures ranging from over 1000 degrees Fahrenheit to room temperature across the engine body. Disadvantageously, these types of engines face difficult material problems such as weld joint cracking and loss of material properties due to thermal cycling over time. Also, there are losses associated with heat radiation from the hot end of these types of engines leading to inefficiency. 
     Piezoelectricity is the ability of some materials (notably crystals and certain ceramics) to generate an electric potential in response to applied mechanical stress. This can take the form of a separation of electric charge across the crystal lattice. If the material is not short-circuited, the applied charge induces a voltage across the material. Direct piezoelectricity of some substances like quartz can generate potential differences of thousands of volts. 
     BRIEF SUMMARY OF THE INVENTION 
     In various exemplary embodiments, the present invention provides systems and methods for collecting and converting solar energy into electrical energy by using solar collectors with multiple closed-cycle thermodynamic engines and/or piezoelectric generators. The solar collectors are configured to collect solar energy and to distribute the collected solar energy in a pulsating manner directly into multiple closed-cycle thermodynamic engines, piezoelectric generators, and the like. The pulsating manner means that the solar energy is allowed to enter into a particular engine or generator periodically, for a predetermined period of time, similar to turning a switch ON and OFF. Advantageously, this enables more efficient use of the collected solar energy. 
     In an exemplary embodiment of the present invention, a solar array distribution system includes a solar energy collector; a distribution mechanism located at an output of the solar collector; and a controller communicatively coupled to the distribution mechanism, wherein the controller is configured to control the distribution mechanism to provide collected solar energy from the solar energy collector to two or more devices in a pulsating manner. The pulsating manner includes providing the collected solar energy into each of the two or more devices for a time period corresponding to a heating cycle for the each of the two or more devices. The time period includes one of a predetermined value and an adaptive setting based on operational conditions associated with the solar energy collector and the two or more devices. Optionally, the distribution mechanism includes an optical switch located in free space at an output of the solar energy collector; and one or more reflective surfaces located in free space, wherein each of the one or more reflective surfaces is positioned substantially adjacent to each of the two or more devices; wherein the controller is configured to control the optical switch and the one or more reflective surfaces to provide the collected solar energy through optically transparent windows on each of the two or more devices. The optical switch can include one of an oscillating reflective surface, a microelectromechanical system, and a refractive switch, and the one or more reflective surfaces each include one of a flat and a curved surface configured to move with the optical switch to minimize the loss of solar energy during the transient part of the optical switch movement. Alternatively, the distribution mechanism includes a plurality of light guides connected to the output of the solar collector; one or more splitters in the plurality of light guides; and a termination on each of the plurality of light guides, wherein the termination is located in a heating chamber of each of the one or more devices. The plurality of light guides include any of FEP, glass, fluorinated polymers, and a thin tube filled with a fluid; and the termination includes a material transparent to infrared radiation and resistant to high temperatures inside the heating chamber. Additionally, the including a reflective portion and a pass through portion; wherein the distribution mechanism is configured to rotate the plurality of rotatable reflective disks to distribute the collected solar energy into each of the two or more devices. The two or more devices each can include any of a generator and a thermodynamic engine; wherein each of the two or more devices include an offset heating cycle from the other two or more devices. The pulsating manner further includes removing heat with a heat removing device from each of the heating chambers not receiving collected solar energy through the distribution mechanism. Optionally, the two or more devices include a piezoelectric generator; wherein the heat removing device includes a plurality of heat exchangers disposed around the heating chamber; and wherein the plurality of heat exchanges include tubes with cooling water. Alternatively, the two or more devices include a closed-cycle thermodynamic; and wherein the heat removing device includes a plurality of heat exchangers disposed around the heating chamber. 
     In another exemplary embodiment of the present invention, a solar array includes a plurality of solar collectors; an optical switch located in free space at an output of each of the plurality of solar collectors; one or more reflective surfaces located in free space, wherein each of the one or more reflective surfaces is positioned substantially adjacent to two or more devices; a controller communicatively coupled to the optical switch and the one or more reflective surfaces, wherein the controller is configured to control the optical switch and the one or more reflective surfaces to provide collected solar energy from the plurality of solar collectors to the two or more devices in a pulsating manner. The pulsating manner includes providing the collected solar energy into each of the two or more devices for a time period corresponding to a heating cycle for the each of the two or more devices. The time period includes one of a predetermined value and an adaptive setting based on operational conditions associated with the solar energy collector and the two or more devices. Optionally, the two or more devices each include a piezoelectric generator. 
     In yet another exemplary embodiment of the present invention, a solar energy conversion method including collecting solar energy; directing the collected solar energy into a first device for a first time period; generating electricity with the first device; repeating the directing and generating steps for one or more devices each for additional time periods each corresponding to the one or more devices; and cooling one or more of the first device and the one or more devices while collected energy is being directed into another device. The solar energy conversion further includes adapting the first time period and the additional time periods based on operational conditions. Optionally, the first device and the one or more devices include piezoelectric generators. The directing step can also be performed by an optical switch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated and described herein with reference to the various drawings, in which like reference numbers denote like system components and/or method steps, respectively, and in which: 
         FIG. 1  is system schematic including a dual-surface reflector for collecting and concentrating solar energy according to an exemplary embodiment of the present invention; 
         FIG. 2  are multiple low-profile solar collectors for providing a flatter and compact low-profile arrangement according to an exemplary embodiment of the present invention; 
         FIG. 3  is a mechanism for combining solar radiation from multiple low-profile solar collectors through light guides according to an exemplary embodiment of the present invention; 
         FIG. 4  is a diagram of various designs for a focusing/collimating element according to an exemplary embodiment of the present invention; 
         FIGS. 5A and 5B  are partial cross-sectional views of a piezoelectric generator according to an exemplary embodiment of the present invention; 
         FIGS. 6A and 6B  are partial cross-sectional views of a thermodynamic closed-cycle based engine according to an exemplary embodiment of the present invention; 
         FIG. 7  is a diagram of an energy distribution and delivery system for concentrated solar energy directly into thermodynamic closed-cycle based engines and/or piezoelectric generators according to an exemplary embodiment of the present invention; 
         FIGS. 8 and 9  are diagrams of a solar array utilizing optical switches and reflective surfaces with the solar collectors of  FIG. 2  according to an exemplary embodiment of the present invention; 
         FIGS. 10 and 11  are diagrams of a solar array utilizing optical switches and reflective surfaces with the dual-surface reflector of  FIG. 1  according to an exemplary embodiment of the present invention; 
         FIGS. 12-15  are diagrams of solar arrays utilizing the distribution mechanism of  FIG. 3  with the solar collectors of  FIG. 2  and the dual-surface reflector of  FIG. 1  according to an exemplary embodiment of the present invention; 
         FIG. 16  is a flowchart of an energy distribution and delivery mechanism for concentrating and releasing solar energy in a pulsating manner directly into multiple systems according to an exemplary embodiment of the present invention; and 
         FIG. 17  is a flowchart of a mechanism to convert solar energy into electric energy according to an exemplary embodiment of the present invention. 
         FIG. 18  is a block diagram of a controller for controlling the pulsating manner of solar energy distribution. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In various exemplary embodiments, the present invention provides systems and methods for collecting and converting solar energy into electrical energy by using solar collectors with multiple closed-cycle thermodynamic engines and/or piezoelectric generators. The solar collectors are configured to collect solar energy and to distribute the collected solar energy in a pulsating manner directly into multiple closed-cycle thermodynamic engines, piezoelectric generators, and the like. The pulsating manner means that the solar energy is allowed to enter into a particular engine or generator periodically, for a predetermined period of time, similar to turning a switch ON and OFF. Advantageously, this enables more efficient use of the collected solar energy. 
     The present invention includes solar collectors that concentrate solar energy and mechanisms for transporting and transferring the concentrated solar energy directly into multiple engines and/or generators without heating the outside surface of the engines and/or generators. Additionally, the present invention includes mechanisms to direct solar energy into each of the multiple engines and/or generators to increase overall system efficiency by maximizing the use of collected solar energy. Advantageously, the delivery system of the present invention avoids heating an outside surface of the multiple engines and/or generators as is done in conventional designs, provides a closed design to protect the collectors, and maximizes efficiency through multiple engines and/or generators and optical splitters. 
     Referring to  FIG. 1 , a dual-surface reflector  100  is illustrated for collecting and concentrating solar energy  102  according to an exemplary embodiment of the present invention. The dual-surfaces on the dual-surface reflector  100  include a primary reflector  104  and a secondary reflector  106 . The reflectors  104 ,  106  can be in a parabolic shape, a spherical shape, and the like. Also, the secondary reflector  106  can be concave or convex depending on the positioning of the secondary reflector  106  relative to the primary reflector  104 . The primary reflector  104  is pointed towards the solar energy  102 , and the secondary reflector  106  is located above the primary reflector  104 . The primary reflector  104  is configured to reflect the solar energy  102  to the secondary reflector  106  which in turn concentrates the solar energy  102  through an opening  108  at a center of the primary reflector  104 . 
     An outer perimeter support ring  110  is disposed around the edges of the primary reflector  104  to maintain the shape of the primary reflector  104  and to anchor in place the primary reflector  104 . A transparent and flexible material  112  connects to the primary reflector  104  and to the support ring  110  to hold the secondary reflector  106  in place. The transparent and flexible material  112  is configured to allow the solar energy  102  to pass through, and can be constructed from a material that is optically transparent in the infrared region, such as a material in the Teflon® family of products, for example, fluorinated ethylene propylene (FEP) or the like. The transparent and flexible material  112  provides a closed design of the dual-surface reflector  100 . Advantageously, the transparent and flexible material  112  can seal the dual-surface reflector  100  from the elements, i.e. wind, airborne particles, dirt, bird droppings, etc. This prevents deterioration of the reflectors  104 ,  106  and reduces maintenance with respect to cleaning the reflectors  104 ,  106 . 
     A support member  114  can be disposed to the outer perimeter support ring  110  and a base  116 . The base  116  can connect to a tracking mechanism  118  through a rotatable member  120 . The tracking mechanism  118  is configured to continuously point the reflectors  104 ,  106  towards the sun by initiating a rotation of the rotatable member  120  to rotate the base  116 , the support member  114  and the support ring  110 . For example, the tracking mechanism  118  can include a microcontroller or the like can rotate according to location (e.g., an integrated Global Positioning Satellite (GPS) receiver, preprogrammed location, or the like), date, and time or the like. Additionally, the tracking mechanism  118  can include feedback from sensors that detect the position of the sun. 
     The base  116  can include one or more motors and electric generators  122 ,  124 . The opening  108  is connected to the base  116  to provide concentrated solar energy from the reflectors  104 ,  106  to the one or more motors and electric generators  122 ,  124 . For a single motor and electric generator  122 , the motor and electric generator  122  is positioned to allow the concentrated solar energy to enter working fluid (e.g., a liquid, a gas, or a phase change substance) without heating an outside surface of the single motor and electric generator  122 . The one or more motors and electric generators  122 ,  124  can include piezoelectric generators, closed-cycle thermodynamic engines, or variations of these. 
       FIG. 1  illustrates an exemplary embodiment with two of the motors and electric generators  122 ,  124 . This exemplary embodiment includes an optical switch  126  and reflecting surfaces  128  to direct the concentrated solar energy into each of the motors and electric generators  122 ,  124 . Those of ordinary skill in the art will recognize that the base  116  can include more than two of the motors and electric generators  122 ,  124  with a corresponding optical switch  126  and reflecting surfaces  128  to concentrate solar energy into each of the more than two of the motors and electric generators  122 ,  124 . The optical switch  126  is configured to provide concentrated solar energy for predetermined intervals into each of the motors and electric generators  122 ,  124 . 
     Advantageously, the optical switch  126  enables the dual-surface reflector  100  to input energy into each of the motors and electric generators  122 ,  124  in a pulsating manner only when needed and for a duration of time that is completely controllable. This enables the dual-surface reflector  100  to avoid wasting collected solar energy, i.e. the optical switch  126  enables the collected energy to be used in each of the motors and electric generators  122 ,  124  as needed. For example, the optical switch  126  can be configured to direct collected solar energy into a heating chamber of each of the motors and electric generators  122 ,  124  only during a heating cycle. The motors and electric generators  122 ,  124  each have offset heating cycles to allow all collected solar energy to be used, i.e. the optical switch  126  cycles between each of the motors and electric generators  122 ,  124  for their individual heating cycles. 
     In an exemplary embodiment, the dual-surface reflector  100  can include inflatable components, such as an inflatable portion  130  between the primary reflector  104  and the secondary reflector  106  and in the outer perimeter support ring  110 . Air lines  132 ,  134  can be connected to the inflatable portion  130  and the outer perimeter support ring  110 , respectively, to allow inflation through a valve  136 , a pressure monitor  138 , and an air pump  140 . Additionally, a microcontroller  142  can be operably connected to the air pump  140 , the pressure monitor  138 , the valve  136 , the tracking mechanism  118 , etc. The microcontroller  142  can provide various control and monitoring functions of the dual-surface reflector  100 . 
     Collectively, the components  136 ,  138 ,  140 ,  142  can be located within the base  116 , attached to the base  116 , in the tracking mechanism  118 , external to the base  116  and the tracking mechanism  118 , etc. The valve  136  can include multiple valves, such as, for example, an OFF valve, an ON/OFF line  132 / 134  valve, an OFF/ON ON/OFF line  132 / 134  valve, and so on for additional lines as needed, or the valve  136  can include multiple individual ON/OFF valves controlled by the microcontroller  142 . 
     The inflatable components can be deflated and stored, such as in a compartment of the base  114 . For example, the inflatable components could be stored in inclement weather, high winds, and the like to protect the inflatable components from damage. The microcontroller  142  can be connected to sensors which provide various feedback regarding current conditions, such as wind speed and the like. The microcontroller  142  can be configured to automatically deflate the inflatable components responsive to high winds, for example. 
     The support member  114  and the outer perimeter support ring  110 , collectively, are configured to maintain the desired shape of the primary reflector  104 , the secondary reflector  106 , and the transparent and flexible material  112 . The pressure monitor  138  is configured to provide feedback to the microcontroller  142  about the air pressure in the inflatable portion  130  and the outer perimeter support ring  110 . The dual-surface reflector  100  can also include controllable relief pressure valves (not shown) to enable the release of air to deflate the dual-surface reflector  100 . The transparent and flexible material  112  can form a closed space  130  which is inflated through the air line  132  to provide a shape of the secondary reflector  106 , i.e. air is included in the interior of the dual-surface reflector  100  formed by the transparent and flexible material  112 , the secondary reflector  106  and the primary reflector  104 . 
     Advantageously, the inflatable components provide low cost and low weight. For example, the inflatable components can reduce the load requirements to support the dual-surface reflector  100 , such as on a roof, for example. Also, the inflatable components can be transported more efficiently (due to the low cost and ability to deflate) and stored when not in use (in inclement weather, for example). 
     In another exemplary embodiment, the primary reflector  104 , the support member  114 , the outer perimeter support ring  110 , the transparent and flexible material  112 , etc. could be constructed through rigid materials which maintain shape. In this configuration, the components  136 ,  138 ,  140  are not required. The microcontroller  142  could be used in this configuration for control of the tracking mechanism  118  and general operations of the dual-surface reflector  100 . 
     In both exemplary embodiments of the dual-surface reflector  100 , the microcontroller  142  can include an external interface, such as through a network connection or direct connection, to enable user control of the dual-surface reflector  100 . For example, the microcontroller  142  can include a user interface (UT) to enable custom settings. 
     The primary reflector  104  can be made from a flexible material such as a polymer (FEP) that is metalized with a thin, highly reflective metal layer that can be followed by additional coatings that protect and create high reflectance in the infrared region. Some of the metals that can be used for depositing a thin reflector layer on the polymer substrate material of the inflatable collector can include gold, aluminum, silver, or dielectric materials. Preferably, the surface of the primary reflector  104  is metalized and coated such that it is protected from contamination, scratching, weather, or other potentially damaging elements. 
     The secondary reflector  106  surface can be made in the same manner as the primary reflector  104  with the reflecting metal layer being deposited onto the inside surface of the secondary reflector  106 . For improved performance, the secondary reflector  106  can be made out of a rigid material with a high precision reflective surface shape. In this case the, the secondary reflector can be directly attached to the transparent and flexible material  112  or be sealed to it (impermeable to air) around the perimeter of the secondary reflector  106 . Both the primary reflector  104  and the secondary reflector  106  can utilize techniques to increase surface reflectivity (such as multi-layers) to almost 100%. 
     The dual-surface reflector  100  operates by receiving the solar energy  102  through solar radiation through the transparent and flexible material  112 , the solar radiation reflects from the primary reflector  104  onto the secondary reflector  106  which collimates or slightly focuses the solar radiation towards the opening  108 . One or more engines (described in  FIG. 5 ) can be located at the opening  108  to receive the concentrated solar radiation (i.e., using the optical switch  126  and the reflectors  128  to enable multiple engines). The collimated or focused solar radiation from the secondary reflector  106  enters through optically transparent window on the engines towards a hot end (solar energy absorber) of a thermodynamic engine. 
     Advantageously, the dual-surface reflector  100  focuses the solar energy  102  and directs it into each of the motors and electric generators  122 ,  124  for their individual heating cycles in a manner that avoids heating engine components other than the solar energy absorber element in the heating chamber of the motors and electric generators  122 ,  124 . Specifically, the opening  108  extends to the optical switch  126  which directs the concentrated solar energy directly into each of the motors and electric generators  122 ,  124  through a transparent window of the heating chamber. The materials forming the opening  108  and the transparent window include materials with absorption substantially close to zero for infrared radiation. 
     The dual-surface reflector  100  includes a large volume, and is preferably suitable for open spaces. For example, the dual-surface reflector  100  could be utilized in open-space solar farms for power plants, farms, etc. In an exemplary embodiment, the dual-surface reflector  100  could be four to six meters in diameter. Alternatively, the dual-surface reflector  100  could be a reduced size for individual home-use. Advantageously, the light weight of the inflatable components could enable use of the dual-surface reflector  100  on a roof. For example, a home-based dual-surface reflector  100  could be 0.1 to one meters in diameter. Also, the reduced cost could enable the use of the dual-surface reflector  100  as a backup generator, for example. 
     Referring to  FIG. 2 , multiple solar collectors  200  are illustrated for providing a flatter and compact arrangement, i.e. a low-profile design, according to an exemplary embodiment of the present invention.  FIG. 2  illustrates a top view and a side view of the multiple solar collectors  200 . In the top view, the multiple solar collectors  200  can be arranged side-by-side along an x- and y-axis. Each of the solar collectors  200  includes a focusing/collimating element  202  which is configured to concentrate solar radiation  102  into a corresponding light guide  204 . The focusing/collimating element  202  is illustrated in  FIG. 2  with an exemplary profile, and additional exemplary profile shapes are illustrated in  FIG. 4 . 
     The focusing/collimating element  202  focuses the solar radiation  102  into a cone of light with a numerical aperture smaller than the numerical aperture of the light guide  204 . The focusing/collimating element  202  can be made out of a material transparent to infrared solar radiation, such as FEP. The focusing/collimating element  202  can be a solid material or hollow with a flexible skin that allows the element  202  to be formed by inflating it with a gas. Forming the element though inflation provides weight and material costs advantages. 
     The light guides  204  can be constructed out of a material that is optically transparent in the infrared region, such as FEP, glass, or other fluorinated polymers in the Teflon® family, or the light guides  204  can be made out of a thin tube (e.g., FEP) filled with a fluid, such as Germanium tetrachloride or Carbon tetrachloride, that is transparent to infrared radiation. Advantageously, the light guides  204  include a material selected so that it has close to zero absorption in the wavelengths of the solar energy  102 . The tube material must have a higher index of refraction than the fluid inside it in order to create a step index light guide that allows propagation of the concentrated solar radiation. The array of the multiple solar collectors  200  can extend in the X and Y direction as needed to collect more solar energy. 
     The focusing/collimating element  202 , the light guide  204  and the interface  206  can be rotatably attached to a solar tracking mechanism (not shown). The tracking mechanism is configured to ensure the focusing/collimating element  202  continuously points toward the sun. A microcontroller (not shown) similar to the microcontroller  142  in  FIG. 1  can control the tracking mechanism along with other functions of the multiple solar collectors  200 . The tracking mechanism can individually point each of the focusing/collimating elements  202  towards the Sun, or alternatively, a group tracking mechanism (not shown) can align a group of elements  202  together. 
     Referring to  FIG. 3 , a mechanism  300  is illustrated for combining solar radiation  102  from the multiple light guides  204  in  FIG. 2  according to an exemplary embodiment of the present invention. The multiple light guides  204  are configured to receive concentrated solar radiation from the focusing/collimating elements  202  and to guide it and release it inside a hot end of multiple engines and/or generators. Optical couplers  302  can be utilized to combine multiple light guides  204  into a single output  304 . For example,  FIG. 3  illustrates four total light guides  204  combined into a single output  306  through a total of three cascaded optical couplers  302 . Those of ordinary skill in the art will recognize that various configurations of optical couplers  302  can be utilized to combine an arbitrary number of light guides  204 . The optical couplers  204  which are deployed in a tree configuration in  FIG. 3  reduce the number of light  204  guides reaching the engines and/or generators. Alternatively, each light guide  204  could be directed separately into the engines and/or generators. 
     An optical splitter  308  and an optical switch  310  can also be included in the optical path (illustrated connected to a light guide  312  which includes a combination of all of the light guides  204 ) at an optimum location along each light guide  204  leading to the engines and/or generators. The optical splitter  308  and optical switch  310  permit pulsation of the concentrated solar energy into one or more piezoelectric generators. Each branch (e.g., two or more branches) of the optical splitter  308  leads to a different engine or generator. The optical switch  310  sequentially directs the concentrated solar energy traveling along the light guide  312  into different arms of the optical splitter  308 . For example, the engines and/or generators can include offset heating cycles with the optical splitter  308  and the optical switch  310  directing solar energy  102  into each engine/generator at its corresponding heating cycle. Advantageously, this improves efficiency ensuring that collected solar energy  102  is not wasted (as would occur if there was a single engine because the single engine only requires the energy during the heating cycle). 
     The optical switch  310  can be integrated into the optical splitter  308  as indicated in  FIG. 3  or it can exist independently in which case the optical splitter  308  could be eliminated and the optical switch  310  can have the configuration presented in  FIG. 1  (i.e., optical switch  126  and reflecting surfaces  128 ). In the case where the optical switch  310  is independent of the light guide  312 , the light guide termination is designed to collimate the light directed towards the optical switch  310 . The selection of the optimum points where the optical splitters  308  are inserted depends on the power handling ability of the optical switch  310  and on economic factors. For example, if the optical switch  310  is inserted in the optical path closer to the engines and/or generators, then fewer switches  310  and shorter light guides  204  are needed, but the optical switches  310  need to be able to handle higher light intensities. 
     Referring to  FIG. 4 , various designs are illustrated for the focusing/collimating element  202   a - 202   e  according to an exemplary embodiment of the present invention. The focusing/collimating element  202   a ,  202   b ,  202   c  each include an optically transparent solid material  402  shaped in either a bi-convex (element  202   a ), a plano-convex (element  202   b ), and a meniscus form (element  202   c ), all of which have the purpose to focus the incoming solar energy  102 . Additionally, each of the elements  202   a ,  202   b ,  202   c  also include a flexible “skin” material  404  that together with the optically transparent solid material  402  form an inflatable structure  406  which can be inflated with air or a different gas. The air/gas pressure in the inflatable structure  406  can be dynamically controlled to maintain an optimum focal distance between the solid material  402  and the engines and/or generators. The optically transparent solid material  402  and the flexible “skin” material  404  are made out of a material transparent to visible and infrared solar radiation, such as FEP, for example. The focusing/collimating element  202   d  is a solid convex focusing element constructed entirely of the optically transparent solid material  402 . 
     The focusing/collimating element  202   e  includes an inflatable dual reflector including a primary reflecting surface  408  and a smaller secondary reflecting surface  410  inside an inflatable structure  406 . The primary reflecting surface  408  and the secondary reflecting surface  410  are configured to collectively concentrate the solar radiation  102  into an opening  412  that leads to the light guide  204 . Both reflecting surfaces  408 ,  410  can be rigid or flexible such as metalized films or only the secondary reflector  410  can be made out of a rigid material with a high precision reflective surface shape. In this case, the secondary reflector  410  can be directly attached to the transparent material  404  or can be sealed to it (impermeable to air) around the perimeter of the secondary reflector  410 . Some of the metals that can be used for metalizing a thin reflector layer on the polymer substrate material of the inflatable collector can include gold, aluminum, silver, or dielectric materials. The preferred surface to be metalized is the inside of the inflatable solar collector such that it is protected from contamination, scratching, weather, or other potentially damaging elements. 
     Techniques to increase surface reflectivity (such as multi layer dielectric coatings) to almost 100% can be utilized. Again, the air/gas pressure can be dynamically controlled, based on feedback from pressure sensors monitoring the inside pressure of the inflatable focusing element, to maintain the optimum focal distance. All transparent materials through which solar radiation and concentrated solar radiation passes through can have their surfaces covered with broad band anti-reflective coatings in order to maximize light transmission. The designs of the focusing elements  202  presented in  FIG. 3  are for illustration purposes and those of ordinary skill in the art will recognize other designs are possible that would meet the purpose and functionality of the focusing elements  202 . 
     The multiple solar collectors  200  can be utilized in buildings, such as office buildings, homes, etc. For example, multiple focusing/collimating elements  202  can be placed on a roof with the light guides  204  extending into the building towards a service area, basement, etc. to the engines and/or generators. Additionally, the light guides  204  heat up very little based upon their material construction. Advantageously, the low profile design of the solar collectors  200  enables roof placement and the light guides enable a separate engine location within a building. 
     Referring to  FIGS. 5A and 5B , a partial cross-sectional view illustrates a piezoelectric generator  500  according to an exemplary embodiment of the present invention.  FIG. 5A  illustrates an exemplary embodiment where concentrated solar energy  102  travels through free space to enter the generator  500  through an optically transparent window  502 . Also, multiple optically transparent windows  502  could be utilized. The optically transparent window  502  is made out of a material transparent to infrared radiation, such as sapphire, fused silica or the like. The shape of the optically transparent window  502  is such that it facilitates sealing of working fluid inside the generator  500  and reduction of back reflection.  FIG. 5A  shows a trapezoidal cross section of the optically transparent window  502  as an exemplary embodiment. The optically transparent window  502  can be disposed at an end of the opening  108  or placed adjacent to the reflecting surfaces  128  of the dual-surface reflector  100  in  FIG. 1 . 
       FIG. 5B  illustrates an exemplary embodiment where concentrated solar radiation enters the generator  500  through a plurality of light guides  504 . Each of the light guides  504  includes a termination  506  that is made out of material transparent to infrared radiation and that is also resistant to the high temperatures inside the generator  500 . The shape of termination  506  facilitates sealing of working fluid inside the generator  506 .  FIG. 5B  shows a trapezoidal cross section of the termination  506 . The termination  506  has an angled tip inside the generator  500  that minimizes back reflection inside the light guide  504  and also minimizes coupling back into the light guide  506  of radiation from the generator  500 . The termination  506  includes a very hard material with good optical properties able to withstand high temperatures. The plurality of light guides  504  can connect to the solar collectors  200  in  FIGS. 2-4 . Additionally, the generator  500  can include fewer light guides  504  than solar collectors  200  utilizing the mechanism  300  in  FIG. 3  to combine light guides  204 . 
     In both  FIGS. 5A and 5B , the optically transparent window  502  and the plurality of light guides  504  transfer concentrated solar energy directly into a heat chamber  508  of the generator  500 . Advantageously, this direct transfer provides a lower temperature of the generator  500  and reduced thermal stress on a generator body  510  of the generator  500 . This leads to longer generator  500  life, better reliability, increased efficiency, and the like. 
     Additionally, the optically transparent window  502  and the plurality of light guides  504  can be configured to transfer the solar energy in a pulsating manner. The pulsating manner means that the solar energy is allowed to enter into the chamber  508  of the generator  500  periodically, for a predetermined period of time, similar to turning a switch ON and OFF. During the OFF period for a particular generator  500 , the solar energy is directed into a second, or third, or other generator  500  in a rotating, periodical fashion. In this way, all the energy from the collector is utilized. Also, during the OFF period for a particular generator  500 , heat is removed from working fluid  510  as part of the thermodynamic cycle. An advantage of pulsating the energy is that solar energy is added to the working fluid  510  in a controlled manner only at the desired time. 
     Transferring the concentrated solar energy directly into the heat chamber  508  of the generator  500  provides great benefits. The generator body  510  has a lower temperature and the thermal stress and thermal aging in the body  510  is reduced. The chamber  508  can be surrounded by heat removing elements  512  such as any type of heat exchanger. The heat exchanger can actually be located inside the chamber  508  to maximize the rate of heat transfer and prevent the walls of the generator  500  from heating up excessively. In an exemplary embodiment, the heat removing elements  512  can include tubes with circulating water being used to remove heat. The heat extracted into the cooling water can be dissipated into the air through another heat exchanger or can be used as a heat source for heating, for example, household water. 
     Advantageously, inserting the solar energy directly into the working fluid  510  in a pulsating manner can improve the efficiency of the generator  500  because the outside temperature of the hot end of the generator  500  can be greatly reduced and therefore the radiated heat loss is decreased. The working fluid  510  can be a gas, typically pressurized, steam, a phase change material, or any other working fluid utilized in closed-cycle thermodynamic engines. The working fluid  510  can include an energy absorbing material that is designed to have a large surface area and is made out of a material that absorbs infrared radiation and that can efficiently release it to the working fluid. Such materials include graphite or other type of carbon based material, a suitable metal, or a metal oxide. The energy absorber can be also include carbon nano particles or other nano size particles uniformly distributed and suspended in the working fluid  510 . 
     A bottom portion  514  of the generator  500  and the heat chamber  510  are attached in a sealed manner through a flexible bellow section  516  that allows the bottom portion  514  to move when the pressure in the heat chamber  510  increases. As a result, the stacks of piezoelectric elements  518  are compressed and a voltage is generated. The piezoelectric elements  518  can be connected in series or parallel (or combination of series and parallel) to generate the desired voltage and current. The electrical energy can be distributed for use or stored for future use. 
     The generator  500  is shown for illustration purposes. Those of ordinary skill in the art will recognize that the dual-surface reflector  100  and the multiple solar collectors  200  can be utilized to concentrate and directly deliver solar energy into any type of generator. 
     Advantageously, the designs described herein enable distributed electrical energy generation from a few kWs to 10&#39;s of kW per unit at a low cost. The present invention can directly generate Alternating Current (AC) electricity without a need for inverters. Also, the present invention can provide heat output which can be used, for example, for space heating, water heating, air conditioning, micro desalination plants, and the like. The present invention provides low installation costs and low overall maintenance costs. Additionally, the present invention can enable a modular design, such as adding additional solar collectors as needed to scale energy generation. 
     Referring to  FIGS. 6A and 6B , a partial cross-sectional view illustrates a closed-cycle thermodynamic based engine  600  according to an exemplary embodiment of the present invention.  FIG. 6A  illustrates an exemplary embodiment where concentrated solar energy  102  travels through free space to enter the engine  600  through an optically transparent window  602 . Also, multiple optically transparent windows  602  could be utilized. The optically transparent window  602  is made out of a material transparent to infrared radiation, such as sapphire, fused silica or the like. The shape of the optically transparent window  602  is such that it facilitates sealing of working fluid inside the engine  600  and reduction of back reflection.  FIG. 6A  shows a trapezoidal cross section of the optically transparent window  602  as an exemplary embodiment. The optically transparent window  602  can be disposed at an end of the opening  108  or placed adjacent to the reflecting surfaces  128  of the dual-surface reflector  100  in  FIG. 1 . 
       FIG. 6B  illustrates an exemplary embodiment where concentrated solar radiation enters the engine  600  through a plurality of light guides  604 . Each of the light guides  604  includes a termination  606  that is made out of material transparent to infrared radiation and that is also resistant to the high temperatures inside the engine  600 . The shape of termination  606  facilitates sealing of working fluid inside the engine  606 .  FIG. 6B  shows a trapezoidal cross section of the termination  606 . The termination  606  has an angled tip inside the engine  600  that minimizes back reflection inside the light guide  604  and also minimizes coupling back into the light guide  606  of radiation from the engine  600 . The termination  606  includes a very hard material with good optical properties able to withstand high temperatures. The plurality of light guides  604  can connect to the solar collectors  200  in  FIGS. 2-4 . Additionally, the engine can include fewer light guides  604  than solar collectors  200  utilizing the mechanism  300  in  FIG. 3  to combine light guides  204 . 
     The engine  600  can include a Stirling-type engine, a Rankine-type engine, or the like. A Stirling engine is a closed-cycle regenerative heat engine with a gaseous working fluid. The Stirling engine is closed-cycle because the working fluid, i.e., the gas in a heat chamber  608  which pushes on a piston  610 , is permanently contained within the engine  600 . This also categorizes it as an external heat engine which means it can be driven by any convenient source of heat. “Regenerative” refers to the use of an internal heat exchanger called a ‘regenerator’ which increases the engine&#39;s thermal efficiency compared to the similar but simpler hot air engine. 
     In both  FIGS. 6A and 6B , the optically transparent window  602  and the plurality of light guides  604  transfer concentrated solar energy directly into the heat chamber  608  of the engine  600 . Advantageously, this direct transfer provides a lower temperature of the engine  600  and reduced thermal stress on a body  612  of the engine  600 . The engine  600  can include a liner  614  made out of a material that is a reflector of infrared radiation and at the same time has poor thermal conductivity (thermal insulator). Advantageously, the liner  614  keeps heat inside the engine  600  avoiding excessive heating of the engine body. This leads to longer engine life, better reliability, increased efficiency, and the like. 
     The heat chamber  608  is delimited at one end by the piston  610  which moves in a reciprocating manner inside the engine  600 . The efficiency of the engine  600  is improved in the present invention because the outside temperature of the hot end of the engine  600  is greatly reduced (compared to conventional designs) and therefore the radiated heat loss is decreased. Inside the heat chamber  608 , the concentrated solar radiation is absorbed and the energy heats up the working fluid in the chamber. The working fluid can be a gas (typically pressurized), steam, a phase change material, or any other working fluid utilized in closed-cycle thermodynamic engines. The optically transparent window  602  can be shaped in a trapezoidal shape or the like to seal the heat chamber  608 , i.e. through the pressurized gas. Alternatively, seals can be located on the optically transparent window  602  or around the plurality of light guides  604 . 
     The heat chamber  608  includes an energy absorber and gas heater  616  which is designed to have a large surface area. The energy absorber and gas heater  616  is made out of a material that absorbs infrared radiation and can efficiently release it to the working fluid such as graphite or other type of carbon-based material, a suitable metal, a metal oxide, or the like. The energy absorber and gas heater  616  can include carbon nano particles or other nano size particles uniformly distributed and suspended in the working fluid. 
     The engine  600  also includes one or more heat exchangers for cooling the gas inside the heat chamber  608  at an appropriate time during the thermodynamic cycle. One or more linear generators or the like (not shown) can be coupled to a rod  618  of the pistons  610 . Generally, the generators are configured to convert mechanical energy from the pistons  610  into electrical energy. The electrical energy can be distributed for use or stored for future use. 
     The engine  600  is shown for illustration purposes. Those of ordinary skill in the art will recognize that the dual-surface reflector  100  and the multiple solar collectors  200  can be utilized to concentrate and directly deliver solar energy into any type of engine. Of note, the present invention delivers concentrated solar energy directly into the heat chamber  608  to avoid heating the engine body. 
     Advantageously, the designs described herein enable distributed electrical energy generation from a few kWs to 10&#39;s of kW per unit at a low cost. The present invention can directly generate Alternating Current (AC) electricity without a need for inverters. Also, the present invention can provide heat output which can be used, for example, for space heating, water heating, air conditioning, micro desalination plants, and the like. The present invention provides low installation costs and low overall maintenance costs. Additionally, the present invention can enable a modular design, such as adding additional solar collectors as needed to scale energy generation. 
     Referring to  FIG. 7 , an energy distribution and delivery system  700  is illustrated for concentrated solar energy that allows the release of the concentrated solar energy in a pulsating manner directly into one or more engines and/or generators according to an exemplary embodiment of the present invention. The energy distribution and delivery system  700  is illustrated with two exemplary engines/generators  702   a ,  702   b , and those of ordinary skill in the art will recognize the energy distribution and delivery system  700  could use additional engines/generators  702  or the like. 
     Each of the engines/generators  702   a ,  702   b  includes a first heating chamber  704   a ,  704   b  and a second heating chamber  706   a ,  706   b . The energy distribution and delivery system  700  is configured to maximize usage of collected solar energy  102  by distributing the solar energy  102  to each heating chamber  704   a ,  704   b ,  706   a ,  706   b  at appropriate times in their respective cycles. For example, the solar energy  102  can be collected utilizing the dual-surface reflector  100  and/or the multiple solar collectors  200  described herein. 
     The energy distribution and delivery system  700  includes multiple reflective disks  710 ,  712 ,  714 ,  716  for distributing the collected solar energy  102 . Note, these reflective disks  710 ,  712 ,  714 ,  716  could be included within a light guide, for example. Additionally, the optical switch and splitter described herein could provide similar functionality to the reflective disks  710 ,  712 ,  714 ,  716 . The reflective disks  710 ,  712 ,  714 ,  716  are configured to either reflect or pass through the collected solar energy  102 . Additionally, each of the reflective disks  710 ,  712 ,  714 ,  716  is configured to rotate to either reflect or pass through the collected solar energy  102 . 
       FIG. 7  illustrates an exemplary operation of the energy distribution and delivery system  700 . The collected solar energy  102 , during a time period  720  (following a dashed line A), passes through an opening of the first disk  710  and enters the heating chamber  704   a  of the engine/generator  702   a . During a time period  722  (following a dashed line B), the concentrated solar energy  102  is reflected off the first disk  710 , passes through the second disk  712 , and reflects off the third disk  716  to enter the heating chamber  704   b  of the engine/generator  702   b.    
     During a time period  724  (following a dashed line C), the concentrated solar energy  102  reflects off the first disk  710 , reflects off the second disk  712 , and reflects off reflectors  730 ,  732  to enter the heating chamber  706   a  of the engine/generator  702   a . The reflectors  730 ,  732  are positioned to direct the concentrated solar energy  102 , and light guides could also be utilized. During a time period  734  (following a dashed line D), the concentrated solar energy  102  reflects off the first disk  710 , passes through the second disk  712  and the third disk  714 , and reflects off the fourth disk  716  and reflective surfaces  740 ,  742  to enter the heating chamber  706   b  of the engine/generator  702   b.    
     The cycle can then start all over again. The energy distribution and delivery system  700  can be used for one, two, or more generator chained in a similar fashion. The size and shape of the reflecting surfaces on each individual disk can be tailored for obtaining optimum performance. For example, the duration of the energy input in any chamber  704   a ,  704   b ,  706   a ,  706   b  can be adjusted by varying the size of the reflecting surface (or a combination of multiple reflecting surfaces) and the rotational speed of the disk  710 ,  712 ,  714 ,  716 . The energy distribution and delivery system  700  can include motors (not shown) configured to rotate the disks  710 ,  712 ,  714 ,  716 . The pulsating manner of energy transfer allows the solar energy to enter into the chamber of the generator periodically, for a controllable period of time, similar to turning a switch ON and OFF. Also, the energy distribution and delivery system  600  can utilize the optical splitter  308  and the optical switch  310  in a similar fashion as the reflective disks  710 ,  712 ,  714 ,  716  to distribute the solar energy  102 . 
     Referring to  FIGS. 8 and 9 , a solar array  800  is illustrated in a schematic top and cross-sectional view according to an exemplary embodiment of the present invention. As illustrated in the top view, the solar array  800  includes a plurality of solar collectors  200  such as described herein. The present invention utilizes various distribution mechanisms to distribute collected solar energy from the solar collectors  200  to multiple engines/generators. Specifically, these mechanisms enable more engine/generators than corresponding solar collectors  200 . Advantageously, the solar array  800  utilizes these distribution mechanisms to more efficiently use collected solar energy. 
     The solar array  800  includes multiple generators  500  ( FIG. 8 ) or engines  600  ( FIG. 9 ). Those of ordinary skill in the art will recognize that the solar array  800  can be utilized with any device adapted to receive concentrated solar radiation. The solar array  800  directs concentrated solar energy through free space to enter the generator  500  or engine  600  through an optically transparent window  502 ,  602 . 
     In the examples of  FIGS. 8 and 9 , the solar array  800  includes four solar collectors  200  with each solar collector  200  providing concentrated solar energy to two generators/engines  500 ,  600 . Each solar collector  200  directs concentrated solar energy in free space to an optical switch  802 . The optical switch  802  is configured to direct the concentrated solar energy to a reflective surface  804 . The optical switch  802  can include oscillating (vibrating) reflective surface or surfaces (such as MEMS), or a refractive switch. The reflective surfaces  804  can be fixed with a flat or curved surface (such that to minimize the loss of solar energy during the transient part of the switch  802  movement) or can move in sync with the optical switch  802  in such a way to minimize the loss of solar energy during the transient part of the switch movement. Other designs, such as based on refractive optical elements, are possible that distribute the light to the desired locations. In this example, there are two reflective surfaces  804 , one for each generator/engine  500 ,  600 . The present invention contemplates additional reflective surfaces  804  as required for additional generators/engines  500 ,  600 . 
     Both the optical switch  802  and the reflective surfaces  804  are configured to rotate to enable concentrated solar energy to be transferred in a pulsating manner directly into the working fluid inside the chamber of the generator/engine  500 ,  600 . The pulsating manner of energy transfer means that the solar energy is allowed to enter into the chamber of the generator/engine  500 ,  600  periodically, for a predetermined period of time, similar to turning a switch ON and OFF. When a particular engine  600  or generator  500  is in the OFF period, the solar energy is directed into the next engine  600  or generator  500  (of the same solar collector  200 ) and so on in a cyclical fashion. In this way, almost all the energy from the solar collector  200  is utilized. 
     Clearly, multiple (more than three) closed-cycle thermodynamic engines  600  and piezo-electric generators  500  can be made to belong to the same solar array  800  and correspond to the same solar collector  200 . For example in  FIG. 8 , an output  810  of the generators  600  from multiple cells can be connected in series, in parallel, or a combination of series and parallel connections in order to optimize the desired overall output. The output  810  of the generators  600  can also be connected in configurations that result in single phase, two phases, or three phases overall outputs. The output  810  is connected to plates at the end of piezo-electric stacks  812 . The cyclical distribution of solar energy into multiple engine-generator combination can be made to match the desired number of output phases. Multiple phase outputs can be generated either from phase shifting outputs from multiple groups of cells, or by having multiple phases coming out of each cell (from multiple generators). 
     During the OFF period of a particular generator/engine  500 ,  600 , heat  820  is removed from the working fluid of that generator/engine  500 ,  600  as part of the thermodynamic cycle, such as the heat exchange mechanisms described herein in  FIGS. 5 and 6 . An advantage of pulsating the energy is that solar energy is added to the working fluid in a controlled manner only at the desired time and for the desired duration. That also allows for a dynamic control scheme of the output power (switches can reconfigure the connection among the outputs from individual generators/engines  500 ,  600 ) for cases when solar energy varies (such as due to clouds). In this way, the output power can change while the voltage and the AC current frequency can stay essentially constant. 
     Referring to  FIGS. 10 and 11 , a solar array  1000  is illustrated in a schematic cross-sectional view according to an exemplary embodiment of the present invention. The solar array  1000  includes a dual-surface reflector  100  or the like configured to collect and concentrate solar energy. The solar array  1000  utilizes similar distribution mechanisms as described in  FIGS. 8 and 9  to distribute collected solar energy from the dual-surface reflector  100  to multiple generators/engines  500 ,  600  thereby enabling more efficient use of collected solar energy. Specifically, these mechanisms enable multiple engine/generators  500 ,  600  for the corresponding dual-surface reflector  100 . Advantageously, the solar array  1000  utilizes these distribution mechanisms to more efficiently use collected solar energy.  FIG. 10  illustrates the solar array  1000  with multiple piezoelectric generators  500 , and  FIG. 11  illustrates the solar array  1000  with multiple closed-cycle thermodynamic based engines  600 . 
     Referring to  FIGS. 12-15 , solar arrays  1200 ,  1400  are illustrated in various schematic views according to an exemplary embodiment of the present invention. Each of the solar arrays  1200 ,  1400  utilize light guides  504 ,  604  with terminations  506 ,  606  directly in heating chambers of the generators  500  and engines  600 . The light guides  504 ,  604  are used to direct the collected solar energy in lieu of free space transmission with optical switches and reflective surfaces. Specifically, the solar arrays  1200 ,  1400  utilize the distribution mechanism  300  described herein in  FIG. 3 . 
       FIG. 12  illustrates the solar array  1200  with multiple piezo-electric generators  500  adapted to receive collected solar energy from multiple solar collectors  200 . In this example, there are two generators  500  for each solar collector  200 . Accordingly, the light guide  504  includes a single switch  310  operable to split the light guide  504  into two directions into separate terminations  506  in each generator  500 . Those of ordinary skill in the art will recognize that each solar collector  200  could serve more than two generators  500  with the addition of splitters and optical switches.  FIG. 13  illustrates the solar array  1200  with multiple closed-cycle thermodynamic engines  600  in a similar configuration. 
       FIG. 14  illustrates the solar array  1400  with multiple piezo-electric generators  500  adapted to receive collected solar energy from a dual-surface reflector  100 . In this example, there are three generators  500  for the single dual-surface reflector  100 . Accordingly, the light guide  504  includes two optical switches  310 , i.e. two switches enable two branches in the light guides  504  to allow a total of three terminations  506 . Thus, the solar array  1400  provides three generators  500  for one dual-surface reflector  100 . The present invention contemplates additional generators  500  with more splitters and optical switches.  FIG. 15  illustrates the solar array  1400  with multiple closed-cycle thermodynamic engines  600  in a similar configuration. 
     Referring to  FIG. 16 , a flowchart illustrates an energy distribution and delivery mechanism  1600  for concentrating and releasing solar energy in a pulsating manner directly into multiple systems according to an exemplary embodiment of the present invention. As described herein, each system can include a piezo-electric generator, a closed-cycle thermodynamic engine, or the like. The distribution and delivery mechanism  1600  collects solar energy (step  1602 ). The collection step can include the mechanisms described herein with respect to the dual-surface reflector  100  and/or the multiple solar collectors  200 . 
     Next, the distribution and delivery mechanism  1600  directs the collected solar energy to a first heat chamber in a first system for a predetermined time period (step  1604 ). The predetermined time period can correspond to a heating cycle for the first system. After the predetermined time period, the collected solar energy is directed to a next first heat chamber in a next system for another predetermined time period (step  1606 ). 
     The distribution and delivery mechanism  1600  checks if there is another system (step  1608 ). Here, the distribution and delivery mechanism  1600  is configured to cycle through all of the system to provide collected solar energy into the associated first heat chambers of each system. If there is another system, the distribution and delivery mechanism  1600  returns to step  1606 . 
     If not, the distribution and delivery mechanism  1600  directs the collected solar energy to a second heat chamber in the first system for a predetermined time period (step  1610 ). Then, the distribution and delivery mechanism  1600  directs the collected solar energy to a next second heat chamber in the next system for a predetermined time period (step  1612 ). 
     The distribution and delivery mechanism  1600  checks if there is another system (step  1614 ). Here, the distribution and delivery mechanism  1600  is configured to cycle through all of the systems to provide collected solar energy into the associated second heat chambers of each system. If there is another system, the distribution and delivery mechanism  1600  returns to step  1616 . If not, the distribution and delivery mechanism  1600  can return to step  1604  for another cycle through each of the heat chambers. 
     Referring to  FIG. 17 , a flow chart illustrates a mechanism  1700  to convert solar energy into electric energy according to an exemplary embodiment of the present invention. The mechanism  1700  includes: continuously positioning one or more solar collectors towards the sun (step  1702 ); collecting solar radiation at each of the one or more solar collectors (step  1704 ); directing the collected solar radiation to a heat chamber in a generator or an engine (step  1706 ); periodically and controllably heating a working fluid in the generator with the directed solar radiation (step  1708 ); reciprocating a piezoelectric generator or a closed-cycle thermodynamic engine responsive to pressure changes in the working fluid (step  1710 ); collecting the generated electrical energy (step  1712 ); cooling the working fluid (step  1714 ), and repeating the mechanism  1700 . 
     Referring to  FIG. 18 , a block diagram illustrates a controller  1800  for controlling the pulsating manner of solar energy distribution according to an exemplary embodiment of the present invention. The controller  1800  can be a digital computer that, in terms of hardware architecture, generally includes a processor  1802 , input/output (I/O) interfaces  1804 , network interfaces  1806 , a data store  1808 , and memory  1810 . The components ( 1802 ,  1804 ,  1806 ,  1808 , and  1810 ) are communicatively coupled via a local interface  1812 . The local interface  1812  can be, for example but not limited to, one or more buses or other wired or wireless connections, as is known in the art. The local interface  1812  can have additional elements, which are omitted for simplicity, such as controllers, buffers (caches), drivers, repeaters, and receivers, among many others, to enable communications. Further, the local interface  1812  can include address, control, and/or data connections to enable appropriate communications among the aforementioned components. 
     The processor  1802  is a hardware device for executing software instructions. The processor  1802  can be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the controller  1800 , a semiconductor-based microprocessor (in the form of a microchip or chip set), or generally any device for executing software instructions. When the controller  1800  is in operation, the processor  1802  is configured to execute software stored within the memory  1810 , to communicate data to and from the memory  1810 , and to generally control operations of the controller  1800  pursuant to the software instructions. 
     The I/O interfaces  1804  can be used to receive user input from and/or for providing system output to one or more devices or components. User input can be provided via, for example, a keyboard and/or a mouse. System output can be provided via a display device and a printer (not shown). I/O interfaces  1804  can include, for example, a serial port, a parallel port, a small computer system interface (SCSI), an infrared (IR) interface, a radio frequency (RF) interface, and/or a universal serial bus (USB) interface. 
     The network interfaces  1806  can be used to enable the controller  1800  to communicate on a network, such as to a client or the like. The network interfaces  1806  can include, for example, an Ethernet card (e.g., 10BaseT, Fast Ethernet, Gigabit Ethernet) or a wireless local area network (WLAN) card (e.g., 802.11a/b/g/n). The network interfaces  8106  can include address, control, and/or data connections to enable appropriate communications on the network. 
     A data store  1808  can be used to store data, such as configuration data and the like. The data store  1808  can include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, and the like)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, and the like), and combinations thereof. Moreover, the data store  1808  can incorporate electronic, magnetic, optical, and/or other types of storage media. In one example, the data store  1808  can be located internal to the controller  1800  such as, for example, an internal hard drive connected to the local interface  1812  in the controller  1800 . 
     The memory  1810  can include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, etc.), and combinations thereof. Moreover, the memory  1810  may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory  1810  can have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processor  1802 . 
     The software in memory  1810  can include one or more software programs, each of which includes an ordered listing of executable instructions for implementing logical functions. In the example of  FIG. 18 , the software in the memory system  1810  includes a suitable operating system (O/S)  1840  and a pulsation control program  1842 . The operating system  1840  essentially controls the execution of other computer programs, such as the pulsation control program  1842 , and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The operating system  1840  can be any of Windows NT, Windows 2000, Windows XP, Windows Vista (all available from Microsoft, Corp. of Redmond, Wash.), Solaris (available from Sun Microsystems, Inc. of Palo Alto, Calif.), LINUX (or another UNIX variant) (available from Red Hat of Raleigh, N.C.), or the like. 
     The pulsation control program  1842  is configured to control the various distribution mechanisms described herein to enable distribution of collected solar energy from one or more solar collectors to multiple engines/generators in a pulsating manner. Specifically, the controller  1800  can be internal or external to the various devices described herein. The controller  1800  is communicatively coupled, such as through the network interface  1806  or I/O interfaces  1804 , to the optical switches, splitters, reflective surfaces, etc. The pulsation control program  1842  is configured to control these devices to distribute energy as required to the multiple engines/generators. For example, the pulsation control program  1842  can perform the distribution based on preconfigured settings or based upon adaptive settings using feedback to determine optimal heating cycle lengths for each engine/generator. The engines/generators and solar collectors can further include embedded sensors which report operational data to the controller  1800 . This operational data can be utilized in the adaptive settings to provide optimal energy generation. 
     Although the present invention has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention and are intended to be covered by the following claims.