Patent Application
20090086348
The present invention relates generally to reflector array positioning systems and more particularly to a system for simultaneously turning and tilting an array of mirror concentrators.
Reflector array positioning systems are well known in the art. For example, U.S. Pat. No. 6,042,240 entitled “Adjustable Three Dimensional Focal Length Tracking Reflector Array” discloses a reflector positioned in orbit about a celestial body to focus sunlight on objects such as space debris to heat up and vaporize such debris. The reflector includes a plurality of units in an array, with each of the units including a plurality of subunits. Each of the units rotates about a first axis and each of the subunits is tiltable about a second axis which is perpendicular to the first axis. A reflecting surface is mounted on each of the subunits such that the reflecting surface rotates with its respective unit and tilts with its respective subunit. Each of the units and each of the subunits is independently controllable.
U.S. Patent Application Publication No. 2004/0074490 entitled “Solar Energy Reflector Array” discloses a heliostat comprising a reflector element and a carrier that is arranged to support the reflector element above a ground plane. A drive means is arranged to impart pivotal drive to the carrier about a fixed, first axis that is, in use of the heliostat, disposed substantially parallel to the ground plane. The heliostat further comprises a means mounting the reflector element to the carrier in a manner which permits pivotal movement of the reflector element with respect to the carrier and about a second axis that is not parallel to the first axis.
Known reflector array positioning systems suffer the disadvantage that they are complex and thus expensive to manufacture and deploy. What is needed therefore is a system for simultaneously turning and tilting an array of mirror concentrators that is of relatively simple construction and inexpensive to manufacture and deploy.
The system for simultaneously turning and tilting an array of mirror concentrators of the invention turns and tilts the array of mirror concentrators simultaneously and with the same angle such that the mirror concentrators precisely follow the trajectory of the sun as it traverses the sky. The array of mirror concentrators is generally arranged in n rows with each row having m mirror concentrators. A first stepper motor turns all of the rows of mirror concentrators simultaneously about a first axis by means of a first lead screw engaged to gears coupled to each row. A second stepper motor tilts the mirror concentrators simultaneously about a second axis by means of a second lead screw coupled to a screw that translates a linkage coupled to each of the mirror concentrators. The first and second stepper motors cooperate to turn the mirror concentrators in a first direction and tilt the mirror concentrators in a second direction simultaneously so that the mirror concentrators track the trajectory of the sun. Such tracking optimizes the reflection of the sun's rays by the mirror concentrators to maximize photovoltaic energy generation of solar cells.
In a first preferred embodiment, the system of the invention is disposed inside an enclosure within which is arranged the array of mirror concentrators. One end of the enclosure includes the first and second stepper motors and driving gears. The top of the enclosure includes a cover made of glass or other light transmissive material. The enclosure provides a sealed environment for the array of mirror concentrators and the turning and tilting mechanisms to protect these from rain, dust, hail, falling leaves and other environmental hazards. The enclosure may be disposed on building structures, for instance, on a south-facing rooftop. By making the mirror concentrators relatively small, the enclosure may be made thin so as to be useful in residential applications. In such applications, the array of mirror concentrators may include a 10×20 array.
In a second preferred embodiment, the array of mirror concentrators may be attached to a fixed framework support. The fixed framework support includes linkages for tilting the mirror concentrators, a first housing for containing the first and second stepper motors, lead screws, gears and linkages and a second housing providing rotation support structures. First and second housings protect these components from the weather. The fixed framework support is tilted so that the mirror concentrators attached thereto face the sun and may be fixed on the top of buildings or on the ground. The mirror concentrators have a relatively larger size of about 1 to 3 feet in diameter to allow for turning and tilting by the stepper motors. The mirror concentrators are preferably separated one from the other to provide for open space therebetween. This arrangement allows for wind to flow between the mirror concentrators to thereby reduce wind drag on the roof or other supporting structure.
The mirror concentrators include an array of flat mirrors made of glass coated on a backside with silver or other reflective material. Sunlight is transmitted through the glass and reflected by the silver surface toward a solar cell. The mirror concentrators further include a structured sheet metal or molded plastic dish that carries the array of flat mirrors and provides protection to the array. The dish provides a means for mounting the mirror concentrators to the turning and tilting mechanisms.
In accordance with one aspect of the invention, a system for simultaneously turning and tilting an array of mirror concentrators includes a first stepper motor operable to drive a first lead screw coupled to each row of the array of mirror concentrators, the rotation of the first lead screw simultaneously turning the rows of the array about a first axis thereof, and a second stepper motor operable to drive a second lead screw coupled to each mirror concentrator of each row, the rotation of the second lead screw simultaneously tilting each mirror concentrator about a second axis thereof
In accordance with another aspect of the invention, a system for simultaneously turning and tilting an array of mirror concentrators includes a first stepper motor operable to drive a first lead screw coupled to each row of the array of mirror concentrators, the rotation of the first lead screw simultaneously turning the rows of the array about a first axis thereof, a second stepper motor operable to drive a second lead screw coupled to each mirror concentrator of each row, the rotation of the second lead screw simultaneously tilting each mirror concentrator about a second axis thereof, and an enclosure within which is disposed the array of mirror concentrators, the first and second stepper motors and the first and second lead screws.
In accordance with yet another aspect of the invention, a system for simultaneously turning and tilting an array of mirror concentrators includes a first stepper motor operable to drive a first lead screw coupled to each row of the array of mirror concentrators, the rotation of the first lead screw simultaneously turning the rows of the array about a first axis thereof, a second stepper motor operable to drive a second lead screw coupled to each mirror concentrator of each row, the rotation of the second lead screw simultaneously tilting each mirror concentrator about a second axis thereof, and a fixed framework support having linkages for tilting each of the mirror concentrators, a first housing for containing the first and second stepper motors, first and second lead screws and a second housing for providing rotation support structures.
There has been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended herein.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of design and to the sequence of steps and processes set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures and methods for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent structures and methods insofar as they do not depart from the spirit and scope of the present invention.
In the drawings:
A system for simultaneously turning and tilting an array of mirror concentrators generally designated 100 is schematically represented in
Each row 120 of mirror concentrators 110 is turned about a first axis A-A thereof by a first stepper motor 125 coupled to a first lead screw 130 that is in turn coupled to a plurality of half tube structures 135 within which the mirror concentrators 110 comprising each row are spacedly attached. Each half tube structure 135 is coupled to a rotating wheel 150 at a first end 140 thereof and to a rotating tube 155 at a second end 145 thereof. The rotating wheel 150 is rotatably disposed within a first wall 160 of the array 105 and the rotating tube 155 is rotatably disposed within a second wall 165 of the array 105. Each rotating tube 155 is coupled to a gear 170 engaged to the first lead screw 130. Rotation of the first lead screw 130 rotates the gear 170 that in turn rotates the rotating tube 155 to provide 180 degrees of rotation to each row 120 as the sun traverses the sky. Each of the mirror concentrators 110 is thus turned simultaneously.
To achieve tilting of the mirror concentrators 110, a second stepper motor 175 is coupled to a second lead screw 180 that is in turn coupled to gears 185. Each gears 185 is in turn coupled to a fine screw 187 coupled to a linkage 189 attached to each mirror concentrator 110 of each row 120 as further described herein. Each mirror concentrator 110 is pivotally attached to opposite rims 190 of a corresponding half tube structure 135. Translation of the linkages 189 is operable to simultaneously tilt the attached mirror concentrators 110 about an axis B-B of each mirror concentrator 110. Axes A-A and B-B are disposed orthogonally one to the other.
With reference to
With reference to
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
The present application claims priority under 35 U.S.C. 119(e) from provisional patent application Ser. No. 60/997,254, entitled “An Array of Mirror Concentrators of Solar Cell Simultaneously Turned and Tilted by Only Two Motors”, filed on Oct. 1, 2007, the disclosure of which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60997254 | Oct 2007 | US |
