Patent Application
20160268968
1. Field of the Invention
The present invention relates generally to solar collection systems. More particularly, the present invention relates to a solar energy collecting device that uses a two stage mirror to generate both electricity directly as well as heating a heat transfer fluid.
2. Description of Related Art
Solar energy is considered as an alternate source of energy relative to conventional forms of energy. Current solar energy collection systems are used to convert solar energy into electrical energy. The solar energy conversion system typically includes photovoltaic modules, photoelectric cells, or solar cells that convert solar energy into electrical energy for immediate use or for storage and subsequent use. Conversion of solar energy into electrical energy includes reception of light, such as sunlight, at a solar cell, absorption of sunlight into the solar cell, generation and separation of positive and negative charges creating a voltage in the solar cell, and collection and transfer of electrical charges through a terminal coupled to the solar cell.
Solar modules are primarily used in residential and commercial areas i.e. in areas served by a grid of an electric utility company. However, an advantage to solar power is that it may be generated anywhere there is sun, allowing it to be a highly mobile source of energy in remote locations.
The amount of electrical energy generated by the solar module is directly related to the amount of solar energy the cells within a module absorb, which in turn is impacted by the cell efficiency, surface area of cell coverage, and the intensity or brightness of the sunlight that is incident on the cells. Cost of a photovoltaic module increases with increased surface area coverage by the photovoltaic cells. One approach for reducing the cost associated with photovoltaic modules is via optical concentration techniques. By employing optical concentration, the cell coverage area within the laminate is reduced.
The concentrated photovoltaic modules with higher efficiency photovoltaic cells can achieve higher power densities than non-concentrated silicon modules by focusing sunlight to the photovoltaic modules using optical concentration techniques. In other words, higher concentration of sunlight together with the high efficiency photovoltaic cells leads to higher power density. However, increased solar energy concentration leads to heating of the photovoltaic module, resulting in increase of temperature of the photovoltaic material. The increase in temperature of the photovoltaic module decreases efficiency of the photovoltaic module, leading to reduced performance of the photovoltaic module. As a result, effective power generated from the photovoltaic module is limited. Moreover, there is a substantial amount of waste heat created that may be otherwise utilized.
Therefore, what is needed is a solar power generating device that may efficiently and portably generate solar power and that may also utilize heat generated by concentrated solar energy.
The subject matter of this application may involve, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of a single system or article.
In one aspect, a solar collecting device is provided. The solar collecting device may comprise a base having a central column and one or a plurality of feet attached to an end of the column. A support shaft may be attached to an opposite end of the column from the feet.
A primary mirror may extend from the support shaft, the mirror having a substantially concave shape formed and/or supported in some embodiments by a plurality of ribs extending from the support shaft. A secondary mirror may be positioned at a focal area of the primary mirror to reflect light from the primary mirror back to a center of the concave shape formed by the primary mirror. In embodiments wherein the primary mirror is trough shaped, the secondary mirror may be long narrow rectangle. In embodiments where the primary mirror is bowl shaped, the secondary mirror may be approximately circular or square shaped.
One or a plurality of solar collectors may be positioned at the center of the primary mirror, likely through a spacing formed by the primary mirror, with the solar collector being below the mirror. The solar collector may be in optical communication with the secondary mirror and positioned to receive a substantial majority of energy reflected from the secondary mirror. The solar collector may comprise a photovoltaic cell array to directly convert solar energy to electricity. Further the solar collector may comprise a heat exchanger configured to allow a heat transfer fluid to gather heat from the solar collector for productive uses.
In another aspect, a kit for assembling a solar collector is provided the kit may comprise a plurality of elements required to assemble the solar collector, packaged in a mobile and durable package. The kit may comprise a central column, a plurality of feet attachable to the column, to form a base. A support shaft may be attachable to the central column.
A primary mirror may be attachable to the support shaft and may extend from the support shaft, the mirror being formed by a plurality of reflective sheets that are slideably mounted between a plurality of ribs, the ribs being attachable to the support shaft. A secondary mirror may be attached to the ribs and/or support shaft and may be positionable at a focal area of the primary mirror. The secondary mirror is configured to reflect light from the primary mirror back to a center of the concave shape formed by the primary mirror. In embodiments wherein the primary mirror is trough shaped, the secondary mirror may be long narrow rectangle. In embodiments where the primary mirror is bowl shaped, the secondary mirror may be approximately circular or square shaped. In one embodiment wherein the mirror is trough shaped, the trough may have a length of 112 inches, an aperture length of 96 inches and a focal length of 36 inches.
A plurality of solar collectors are provided in the kit and are attachable to the support shaft, each of the solar collectors being cylindrically shaped and having a length approximately equal to a spacing between each of the plurality of ribs along the support shaft, each of the plurality of solar collectors being in optical communication with the secondary mirror when attached to the support shaft. Each of the plurality of solar collectors comprise a photovoltaic cell array, wiring attached to the photovoltaic cell array and connectable to an electronic device, a heat exchange aperture passing through the collector, tubing attached to an inlet and an outlet of the aperture, connectable to a pump configured to circulate fluid, and a glass tube at least partially surrounding the photovoltaic cell array, a vacuum being drawn within an annulus formed between the glass tube and the photovoltaic cell array.
Finally the kit may include a dual axis movement device attachable to the solar collecting device to provide movement to the primary mirror. The dual axis movement device may comprise a motor to power the movement device, and a gear box, hydraulic piston, or the like to provide movement to the primary mirror.
The detailed description set forth below in connection with the appended drawings is intended as a description of presently preferred embodiments of the invention and does not represent the only forms in which the present invention may be constructed and/or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiments.
Generally, the present invention concerns a two stage solar collecting device. The device comprises a primary mirror, a secondary mirror, and a solar collector. The present invention may be constructed to be modular, mobile, and easily reparable. Moreover, the present invention utilizes a number of structural optimizations to utilize as much energy from the system as possible and thereby increase efficiency.
The solar collecting device may have a base that provides support for the mirrors, solar collector, and various other components of the device. In one embodiment the base may comprise feet, a central column extending upwards, and a support shaft attached perpendicularly from the central column. In a further embodiment the column and shaft may be hollow to provide a housing and storage area for components, tubing, wires, and the like. Further the central column may be adjustable in height to raise or lower the device.
A plurality of ribs may be attached to or extend from the support shaft. The ribs form a concave shape such as a trough or bowl which provides support and shaping of the primary mirror. In one embodiment, the ribs may be spaced equidistantly along the length of the shaft forming a trough. In a further embodiment, the ribs may be spaced at approximately 12 inch intervals along the length of the support shaft. The ribs may add rigidity to the mirror, provide a uniform shape of the mirror and may ensure a uniform focal line of the parabolic mirror assembly. In another embodiment, the support shaft may be formed as a substantially round block, the ribs protruding therefrom and forming a bowl.
The ribs may be constructed of any material capable of providing rigidity to the mirror and capable of supporting the reflective sheets. In one embodiment, the ribs may be constructed of aluminum. However, other materials contemplated herein may include other metals, high temperature plastics, wood, and the like.
In one embodiment, the ribs may have a precise parabolic curve milled into opposing sides. Reflective sheets may be slideably secured between ribs by being slid into the milled curve of two ribs being secured there between. This embodiment provides a highly accurate, curved mirror formed by the precision milling. Further the reflective sheets of this embodiment may be easily replaceable and easily assembled.
A spacing may be provided in the reflective sheets along a bottom of the concave shape formed by the ribs. In one embodiment, this spacing may be at a bottom of a trough, in line with the support shaft. In this embodiment, this spacing may be formed by a reflective single sheet with an aperture formed therein. In another embodiment one sheet may be inserted on one side of the shaft and may stop at a point nearly to the bottom of the trough, while a second sheet may be inserted on the opposite side of the shaft and may stop at a point nearly to the bottom of the trough. The two sheets forming a spacing. A solar concentration ratio may be determined based on primary mirror width compared to focal point or line width. In one embodiment, this ratio may be approximately 100:1. In another embodiment, this ration may be approximately 240:1.
As such this embodiment primary mirror is trough shaped and formed by the combination of the ribs and reflective sheets attached to the ribs. However, it should be understood that the primary mirror may be formed as a trough or other shape and may be constructed in any manner without straying from the scope of the present invention.
Furthermore, the reflective sheets may be constructed of any material capable of maintaining a relatively uniform shape and capable of mounting to the ribs, either by sliding within the milled groove formed by the ribs, or otherwise. In one embodiment, the reflective sheets are constructed of a stainless steel base layer laminated with a reflective material on at least one side. However, other materials contemplated herein may include other metals, metals laminated with a reflective material, plastics laminated with a reflective material, and the like.
A secondary mirror may be positioned along a focal area formed by the concave primary mirror. In one embodiment, the secondary mirror is configured to redirect the light reflected to the focal line by the primary mirror back to the spacing at the center bottom of the primary mirror. The secondary mirror may be configured to further focus incoming light, or may be flat and simply redirect the incoming light.
The secondary mirror may be any reflective material capable of being suspended above the primary mirror by a support. In one embodiment, the secondary mirror may be milled from an aluminum blank, ground to a final polish, and optionally given an anodized surface treatment.
In one embodiment, the secondary mirror may be supported at its end points by supports extending from various parts of the device such as the support shaft and/or a rib. Support of the secondary mirror may vary depending on size of the mirror and intended operating conditions of the solar collecting device. In a further embodiment, the secondary mirror may be removably attached to the supports, thereby facilitating portability and assembly of the device. In still a further embodiment, the supports may be removably attached to the ribs and/or support shaft.
In another embodiment, the secondary mirror may have an adjustment device to position and reposition the mirror such that it redirects light effectively to the spacing of the primary mirror. In one embodiment the adjustment device may be one or a plurality of threaded connectors and screws, the adjustment being performed by twisting the connector to slowly move the mirror as desired. In another embodiment, the adjustment device may be slideable within a track about certain ranges. In another embodiment, the adjustment device of the secondary mirror may be a linear actuator. This actuator may be a motor or pneumatically driven, among other options. The adjustment device allows for minor corrections of the secondary mirror to maintain reflected light directly on the photovoltaic cell array.
In still another embodiment, the secondary mirror may be configured to absorb heat via a heat sink attached to it. Through the heat sink, one or a plurality of apertures may be formed to allow the flow of a fluid there through. The fluid may be configured to absorb and transfer heat from the heat sink of the mirror. In one embodiment, the fluid flow may be performed by a pump. In another embodiment, this fluid flow may be integrated with the cogeneration fluid flow of the solar collector as discussed below.
A solar collector may be positioned within the support shaft, and may be oriented to receive the solar energy reflected and focused by the primary mirror, and redirected by the secondary mirror through the spacing of the primary mirror. In one embodiment, the support shaft may form an aperture in line with the spacing of the primary mirror. This configuration of the solar collector may enhance durability, ease of assembly, and maintenance of the device. The solar collector may be any device capable of receiving and transferring the solar energy collected by the device.
In one embodiment, the solar collector may be a heatable conduit. In this embodiment, heat generated by the concentrated solar energy directed to the solar collector may be transferred for use in productive applications, such as building heat, boiling water for desalination or electricity production, and the like.
In another embodiment, the solar collector may be a photovoltaic (PV) cell array. Photovoltaic cells allow conversion of solar energy to electricity. In this embodiment, wires may carry electricity produced directly to electronic devices, batteries or other electronic storage, or to a local power grid. PV cells contemplated herein may be single junction cells, crystalline silicone (c-Si), triple junction cells, or any other unit capable of conversion of light energy into electricity.
In still another embodiment, the solar collector may be a cogeneration device, utilizing both a PV cell array, and a heat transfer system. In this embodiment, the heat transfer system may serve two purposes: the first is to utilize waste heat absorbed by the PV array, and the second is to maintain the PV array at an optimal working temperature of approximately 25 degrees Celsius, thereby maximizing PV cell efficiency. It should be understood that there may be different temperatures to substantially maximize operating efficiency depending on the configuration of the PV array.
Solar collectors may be constructed of various materials depending on the type of use. Generally the solar collectors may be constructed of metals, heat resistant plastics, glass, ceramics, or combinations thereof.
In cogeneration embodiments, the solar collector may comprise a PV cell array, a fluid flow system having inlet and outlet tubing, and electrical wiring. Further, a glass covering or tube may encase these elements. The glass may partially or fully encase the collector. In one embodiment a full glass tube may encircle the collector. In another embodiment, a glass plate may be placed over the PV cell array, and sealed to an encasing material such as a metal or plastic tube.
A vacuum may be drawn within the glass tube which may maximize insulation, properly modulate temperature of the PV cells, and limit oxygen exposure to the PV cells. In a further embodiment, caps may be provided on each end to seal the tube. The caps may be easily removed to allow access to the internal structure of the solar collector. In still a further embodiment, the electrical, fluid, and vacuum flows may be mounted to one or both of the caps. In another embodiment, in addition to the vacuum drawn on the solar collector, a supplemental vacuum may be drawn within the support shaft to provide further insulation to components therein.
In one embodiment, the cogeneration fluid may travel through dual coaxial tubing. In this embodiment, the fluid may travel through an interior tube, and an exterior tube may be used for drawing and maintaining a vacuum within the glass tube of the solar collector. As such the cogeneration fluid may be further insulated by the vacuum surrounding it in the tube. In a further embodiment, the cogeneration fluid tubing may be kept within the support shaft and base column for as long as possible until exiting the device for use. Embodiments which contain the fluid tubing internally may provide added efficiency particularly in cold weather environments by providing additional insulation to the fluid.
A vacuum pump may be attached to the tubing to draw the vacuum above discussed. In one embodiment, the vacuum pump may utilize electricity generated by the PV array directly.
The solar collector may be configured to be modular, easily installable and easily replaceable. In one embodiment, a plurality of solar collectors may be used along the length of the solar collector. In a further embodiment, one solar collector may be positioned between each set of ribs. In this embodiment, the solar collectors may be easily removed for repair or replacement while still allowing the functioning solar collectors to operate properly. In still a further embodiment, the electronics and/or tubing may be installed in parallel such that failure of one of the plurality of solar collectors does not impair functionality of the others.
In a further embodiment, the solar collector may be installed by snapping into place. Further, the inputs to the solar collector such as fluid flow, electric flow and vacuum tubing may be easily connected by, for example, snap in fittings, pressure fittings, swage fittings, threaded fittings, and the like.
The solar collecting device may further comprise a dual axis adjustment mechanism. This mechanism may move the primary mirror left to right and also angle it upwards and downwards. This allows the mirror to track the movement of the sun throughout the day to ensure that the mirror is receiving a maximum amount of sunlight. The dual axis adjustment mechanism may utilize any structure to allow movement. In one embodiment, gearing may operate to achieve the desired motion. In another embodiment, hydraulics may move the mirror. In still another embodiment gas pistons may be utilized.
In one embodiment, a single device may control the side to side motion and the up and down angled motion. In another embodiment, different devices may control the side to side motion and the up and down motion. For example, the dual axis adjustment mechanism may have a hydraulic pump which may control two pistons, one to control left to right movement of the primary mirror, and another to control up and down angling of the primary mirror.
In a further embodiment, a computer may be programmed and configured to control the dual axis adjustment mechanism. In still another embodiment, the computer may automatically calculate optimal mirror tracking based on, for example, latitude and longitude, time, and/or date. In one embodiment, a global positioning system may be utilized to provide this data to the computer. The computer may utilize this calculated tracking to activate the adjustment mechanism to cause the mirror to follow this optimal track.
The present invention is configured to be easily set up, maintained and used. In one embodiment, assembly and use of the present invention may begin by attaching feet and the support shaft to the central column. The feet can be secured to the ground by resting on flat ground, or being secured to the ground by stakes and the like, for example by passing through an opening in a foot, or through any other connection means. A support shaft may be mounted to the central column. The plurality of ribs may be attached to the support shaft to form the trough or bowl shape of the primary mirror. Next, reflective sheets may be disposed between the ribs to form the primary mirror. The secondary mirror may be attached to the support shaft and/or ribs and aligned on the focal area formed by the primary mirror. The secondary mirror may then be configured to direct energy to the solar collector which is secured within the support shaft and accessible to light and other solar energy by a spacing in the mirror and an aperture formed by the support shaft. One or a plurality of solar collectors may be removably attached within the support shaft. The solar collector may be easily connected to tubing and wiring to allow the flow of electricity and heat transfer fluid out of the collector. This wiring and tubing may travel within the support shaft, through the central column, and out of the device to its destination. In a further embodiment, a computerized tracking system may control a two axis adjustment mechanism to track the sun's movement along two axes.
In one embodiment of maintenance, in the event that one of a plurality of solar collectors is damaged, the present invention allows for a new solar collector to be easily installed. The damaged collector may be removed by disconnecting a tubing and/or wiring, and disconnecting it from its position within the support shaft. The new solar collector may then be installed by connecting it to the open position within the support shaft, and then connecting the disconnected tubing and wiring. In some modular designs and kits, one or multiple spare solar collectors may be provided for easy replacement and minimal downtime if an operating solar collector is damaged. Further, the device may have a storage area to store spare solar collectors.
Other examples of the use of various embodiments of the present invention may include air dropping into remote locations, flat packing for remote assembly, inclusion in payloads on remote travel vehicles, and the like.
Turning now to
In one embodiment, the secondary mirror 22 may be specially configured to reflect incoming radiation that will be absorbed by the photovoltaic cell array. In one embodiment, the secondary mirror 22 may reflect incoming radiation in the range of approximately 400 to 1300 nm. In one embodiment, the secondary mirror 22 may reflect incoming radiation in the range of approximately 900 to 1300 nm. In some partially reflecting embodiments, the secondary mirror 22 may then be configured to be transparent to at least a portion of a remainder of incoming radiation. In other partially reflecting embodiments, the secondary mirror may be configured to absorb at least a portion of a remainder of the incoming radiation.
A heat exchanger 162 may be configured to be in contact with or spaced slightly away from the secondary mirror 22. In an embodiment wherein the secondary mirror 22 is transparent to non-reflected radiation, the heat exchanger 162 may be spaced apart from the secondary mirror 22, and the radiation may directly contact the heat exchanger 162, converting to heat. In an embodiment wherein the secondary mirror 22 absorbs non-reflected radiation, the heat exchanger 162 may be in contact with the mirror 22. The heat exchanger 162 then absorbs incoming radiation on the secondary mirror 22 that has been converted to heat energy. Both embodiments serve to both cool the mirror and to absorb useful heat energy to a working fluid which may be transferred for productive use. Working fluid may be provided from another pass from the primary heat exchanger in the photovoltaic cell array, or may be a separate fluid. A second heat exchanger 163, which may be a second pass of the heat exchanger 162, or a separate heat exchanger. Heat exchanger 163 is configured to be attached to or in contact with the photovoltaic cell 161. This serves to both cool the photovoltaic cell 161 and to absorb useful heat energy to a working fluid which may be transferred for productive use. Working fluid may be provided from another pass from the primary heat exchanger in the photovoltaic cell array, or may be a separate fluid. In one embodiment, the heat exchangers 162, 163 may be connected together and to the photovoltaic cell 161, and may be movable with the cell 161 between the first and second position.
In a particular embodiment having a secondary mirror 22 that is transparent to non-reflected radiation, when the photovoltaic cell 161 is in the second position (which is by the reflective side of the secondary mirror 22), incoming radiation from the sun may pass through the secondary mirror to provide radiation to heat exchanger 162.
While several variations of the present invention have been illustrated by way of example in preferred or particular embodiments, it is apparent that further embodiments could be developed within the spirit and scope of the present invention, or the inventive concept thereof. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention, and are inclusive, but not limited to the following appended claims as set forth.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13459754 | Apr 2012 | US |
| Child | 15162766 | US |
