|Publication number||US20080210220 A1|
|Application number||US 11/967,650|
|Publication date||Sep 4, 2008|
|Filing date||Dec 31, 2007|
|Priority date||Dec 30, 2006|
|Publication number||11967650, 967650, US 2008/0210220 A1, US 2008/210220 A1, US 20080210220 A1, US 20080210220A1, US 2008210220 A1, US 2008210220A1, US-A1-20080210220, US-A1-2008210220, US2008/0210220A1, US2008/210220A1, US20080210220 A1, US20080210220A1, US2008210220 A1, US2008210220A1|
|Inventors||Johan A. Perslow|
|Original Assignee||Perslow Johan A|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (2), Classifications (15), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims priority to and the benefit of U.S. Provisional Patent Application No. 60/882,909, filed Dec. 30, 2006, the entire contents of which are expressly incorporated herein by reference.
The present invention relates to energy systems, and more specifically to systems that convert and store solar energy.
Solar panels made up of a plurality of photovoltaic (PV) cells are often used for the direct conversion of sunlight to electrical energy. Such panels may be mounted on rooftops or other exterior structures exposed to the sun to provide electric power for use by or within the structure. In addition to receiving power from the panels, a structure may be connected to the local power grid to draw power from the grid at night or during overcast days and even to provide power to the grid when the amount of power created exceeds the energy usage of the structure.
The amount of sunlight that a solar panel absorbs, and therefore the amount of electrical energy it generates, varies greatly with its orientation relative to the sun. PV cells provide their maximum output when solar rays impact them in a direction that differs from the perpendicular or “normal” direction by no more than a preselected angle. When sunlight impinges on PV cells at an angle that differs appreciably from the preferred, normal direction, their output decreases. Therefore, solar panels may be mounted at an angle with respect to the horizon to increase the amount of sunlight that impacts them at angles close to the normal direction. In addition, systems have been proposed for moving solar panels over the course of a day to “track” the sun as it moves across the sky. Such systems can be made to closely approximate normal incidence on a continuous basis, but they are also rather complex and expensive to operate and maintain.
Thus, there is a need for a simple and effective system for increasing the proportion of incident sunlight that impacts at an angle sufficient for it to be absorbed by the panels and therefore converted to electrical energy. In addition, there is a need for solar energy systems that can efficiently and conveniently store the energy collected during daylight hours for later use.
The solar energy system of the present invention provides a simple and efficient mechanism for capturing, converting, and storing solar energy. The system includes a plurality of solar panels mounted at an angle on a flotation device floating on a body of water. A mechanism rotates the flotation device to substantially track the sun as it traverses the sky. The rotation of the flotation device and angled solar panels increases the proportion of incident sunlight that impacts the panels in an approximately perpendicular direction, allowing the sunlight to be absorbed by the panels and converted to electrical energy. The system may also store energy collected during the day for later use by pumping water to a higher elevation, where the solar energy is stored in the form of potential energy of the elevated water.
In an embodiment of the invention, a solar energy system includes a flotation device floating on a body of water; a plurality of solar panels supported on the flotation device, each of the solar panels being inclined in the same direction relative to the surface of the water; and a mechanism for rotating the flotation device on the body of water to substantially track the sun as it moves across the sky.
In another embodiment of the invention, the solar energy system includes first and second bodies of water, the second body of water being located at a higher elevation than the first body of water; at least one flotation device floating on at least one of the bodies of water; a plurality of solar panels mounted at an angle on the flotation device; a mechanism for rotating the flotation device to track the sun; a pump electrically coupled to the solar panels and configured to pump water from the first body of water to the second body of water; and a turbine positioned between the first and second bodies of water to extract energy from the water flowing from the second body of water to the first body of water.
In yet another embodiment of the invention, a solar energy system also includes a mechanism for adjusting the angle at which the solar panels are mounted on the flotation device. The system may also include a controller that controls rotation of the flotation devices to rotate them approximately 360° in 24 hours. The solar energy system may also include a connection to the external power grid.
These and other features and advantages of the present invention will be appreciated as the same become better understood with reference to the specification, claims, and appended drawings wherein:
The detailed description set forth below in connection with the drawings is intended as a description of the presently preferred embodiments of a solar energy generation and storage system provided in accordance with the present invention and is not intended to represent the only forms in which the invention may be constructed or utilized. It is to be understood that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. As denoted elsewhere herein, like element numbers indicate like elements or features.
During the day, the solar panels 28 absorb incoming sunlight and generate electricity. Motors 54 and 56, which engage the outer edges of the arrays 16 and 18, rotate the arrays about their central shafts 20 and 22. Although
The solar panels 28 may be any available type of solar panel including substrate-based devices such as single crystalline or polycrystalline silicon devices, or thin film devices such as amorphous or microcrystalline silicon, or any of a variety of compound semiconductor devices. In one embodiment, the solar panels 28 are polycrystalline silicon devices of the type marketed by General Electric Company as model no. GEPVp-200.
The panels 28 are mounted on the flotation devices 26, which float on the surface of the ponds. The flotation devices 26 may be constructed of a suitable closed cell foam, such as Styrofoam™, or any other suitable foam or non-foam material, such as polystyrene or polyethylene materials or combinations. The devices may be coated with composite carbon or glass fiber reinforced material or any other suitable coating known in the art. The arrays 16 and 18, including all of the flotation devices 26 and solar panels 28, may be of any desired size, and in one embodiment weigh between 10,000 and 20,000 tons. In such a case, each pond 12 and 14 may occupy between 50 and 200 acres. The ponds 12 and 14 may be lined with a water-impermeable material to prevent water leaks. For example, the ponds may be lined with a water-tight earthen material such as clay, or with polyvinyl chloride (PVC), cement, or any other suitable water-tight material.
Two flow channels connect the ponds 12 and 14. A first flow channel 34 connects the lower pond 12 to the upper pond 14. A pump 30 located in the first flow channel 34 pumps water from the lower pond 12 to the upper pond 14. A second flow channel 36 connects the upper pond 14 to the lower pond 12. A turbine 32 is located in the second flow channel 36 to extract energy from water flowing from the upper pond 14 down to the lower pond 12.
During the day, sunlight shines on the solar panels 28, and the motors 54 and 56 rotate the solar panels to track the sun through the sky. The solar panels 28 generate electricity, which may be used to power the pump 30 to move water from the lower pond 12 to the upper pond 14. If the solar panels 28 generate more electricity than is needed to operate the pump 30, the surplus electricity can used otherwise or sold to the external power grid.
After the sun sets, at least some of the solar energy collected during the day by the solar panels 28 may remain stored in the form of potential energy of the elevated water in the upper pond 14. This potential energy can be captured and converted into electricity by allowing the elevated water in the upper pond 14 to drain through the second flow channel 36, across the turbine 32, and into the lower pond 12. The flowing water powers the turbine 32 to generate electricity. Thus, the solar energy system 10 enables solar energy to be collected during the day, stored as potential energy, and then used at any later time to satisfy a demand for electric power. After the elevated water powers the turbine 32 and returns to the lower pond 12, it can be pumped back to the upper pond 14 the next day, when the sun rises and shines on the solar panels 28.
The solar energy system 10 may also be connected to an external power grid (not shown) so that surplus energy generated by the solar panels 28 during the day can be sold to the power grid. The solar panels 28 may be connected to the external power grid through the central shafts 20 and 22. A slip ring fitted to the central shaft can maintain the electrical connection to the solar panels 28 as they rotate. The electricity generated by the turbine 32 when water is drained from the upper pond 14 to the lower pond 12 can also be sold to the external power grid, or it can be used locally. Additionally, at times when the external power grid has surplus energy, that energy can be used to drive the pump 30 to move water from the lower pond to the upper pond. The solar energy system can thus store excess energy from the power grid in the form of potential energy of the elevated water in the upper pond 14.
As the sun travels across the sky during a day, the motors 54 and 56 rotate the arrays 16 and 18 around the central shafts 20 and 22 in order to point the angled solar panels 28 generally toward the sun. This increases the amount of sunlight the solar panels 28 absorb and the amount of electricity they produce. The ponds 12 and 14 facilitate the rotation by providing a low-friction surface on which the arrays 16 and 18 can rotate. This low-friction surface reduces the amount of energy required to drive the motors 54 and 56 that rotate the arrays of solar panels. Once the motors overcome the inertia of the large arrays 16 and 18, the arrays rotate easily on the water. The low-friction water surface of the ponds thus contributes to the overall energy efficiency of the system.
A gap 24 separates the outer edge of the arrays 16 and 18 from the outer edges of the ponds 12 and 14. In a preferred embodiment, the gap may range from about 40 to about 60 feet in width. This gap provides a ring of exposed water surrounding the arrays 16 and 18. This exposed water deters animals from jumping or walking onto the arrays 16 and 18 and possibly damaging the flotation devices 26 and solar panels 28. The gap also eliminates friction or interference between the edge of the array and the edge of the pond as the array rotates.
A third embodiment is shown in
In the embodiments of
Referring now to
In the embodiment shown in
The optimal angle of incline Θ depends on the latitude of the site where the solar energy system is located. At each latitude, an angle can be selected to provide the panels 28 with a large proportion of the available sunlight over the course of a day as the array of panels rotates. It will be understood, however, that no fixed angle can provide an optimal orientation at all times. Rather, the fixed arrangement disclosed herein is a compromise intended to approximate, as closely as possible, a normal angle of incidence over the course of a year. While the disclosed arrangement is less efficient in terms of solar energy conversion than a full two-axis tracking system, the advantage lies in the fact that the conversion efficiency is considerably higher than a stationary system with much less mechanical complexity and expense than a two-axis system.
In another embodiment, also shown in
Also, because the solar panels 28 are angled, dirt and debris tends to roll or slide off, instead of accumulating on the panels. However, fine dust particles may still accumulate on the top surfaces of the panels 28, decreasing the efficiency of the panels by blocking incoming solar radiation. Therefore, the solar energy system 10 of the present invention may include a sprinkler system 70 (
Although limited embodiments of the solar energy system and its components have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that the solar energy system and its components constructed according to principles of this invention may be embodied other than as specifically described herein. The invention is also defined in the following claims.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8056554||Nov 4, 2009||Nov 15, 2011||Nolaris Sa||Man made island with solar energy collection facilities|
|US20110100358 *||Sep 1, 2010||May 5, 2011||Randal Jerome Perisho||Low Cost Fixed Focal Point Parabolic Trough|
|Cooperative Classification||F24J2/4607, F24J2002/0084, Y02E10/47, H02S20/00, F24J2/523, F24J2/5267, F24J2/5406, Y02E10/50|
|European Classification||H01L31/042B, F24J2/52A8, F24J2/46B, F24J2/52C, F24J2/54B2|
|Apr 8, 2008||AS||Assignment|
Owner name: JOHAN PERSLOW, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PERSLOW, JOHAN A.;REEL/FRAME:020774/0369
Effective date: 20080404