Lightweight, low cost solar energy collector

Abstract

A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two spaced anchorplates, each containing a plurality of holes, which lie on a desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers, which control the shape, and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape. A plurality of bridges and or retention clips may be employed in certain embodiments to maintain the position of the reflective surface relative to the fibers.

Description

CROSS-REFERENCE TO CORRESPONDING APPLICATIONS[0001]This application takes priority from provisional patent application Ser. No. 60 / 412,518 filed on Sep. 20, 2002 and from utility patent application Ser. No. 10 / 601,923 filed on Jun. 19, 2003.ORIGIN OF THE INVENTION[0002]The invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of public law 96-517 (35 USC 202) in which the contractor has elected to retain title.BACKGROUND OF THE INVENTION[0003]1. Technical Field[0004]The present invention relates generally to the field of solar collectors having a parabolic trough to collect and concentrate solar energy. The invention pertains more specifically to an extremely lightweight and low cost parabolic trough solar collector.[0005]2. Background Art[0006]Parabolic trough technology is currently the most advanced solar thermal electric generating technology. This is primarily due to nine large commercial-scale solar power plants,...

AI Technical Summary

Benefits of technology

[0015]The anchorplates are centrally fastened to circular endplates. These endplates also serve to seal the ends of a transparent thin film cylindrical enclosure tube, which functions as a housing. The enclosure tube may be seamless or may comprise one or more seams which enable the enclosure tube to be formed from a flat flexible sheet. Once sealed, raising the pressure of the gas (air) inside the enclosure tube increases the stiffness of the enclosure tube. With only a modest internal pressure the enclosure becomes structurally stable with the capability to provide a weather tight housing for the internal mirror, receiver and other components. In addition, the inflated enclosure is designed with endplates that impart a portion of their pressure load into the anchor plates and hence the reflector forming fibers. In this manner, tension is provided to the fibers without using additional costly structure.

[0016]Because of the tension, sag or deformation of the array of fibers can be minimized even in the presence of the gravitational load represented by the reflector sheet. As tension is increased, deformation of both fiber and reflector is reduced and the reflector is even further constrained to follow the specific parabolic contour defined by the array of fiber-locating holes.

Problems solved by technology

Also, neither such patent discloses a transparent tubular enclosure that is pressurized to generate the tension in the fibers.

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