Abstract: Described herein are solar reflectors which provide a low cost reflector construction that has a unique set of attributes: high solar reflectance, abrasion resistance, UV stability, mechanical integrity, and flexibility. The abrasion resistance is enabled through incorporation of an abrasion-resistant coating into a polymer film metal mirror construction. Methods of using the solar reflectors in solar concentrating applications are also provided.

Abstract: Provided are reflective thin film constructions including a reduced number of layers, which provides for increased solar-weighted hemispherical reflectance and durability. Reflective films include those comprising an ultraviolet absorbing abrasion resistant coating over a metal layer. Also provided are ultraviolet absorbing abrasion resistant coatings and methods for optimizing the ultraviolet absorption of an abrasion resistant coating. Reflective films disclosed herein are useful for solar reflecting, solar collecting, and solar concentrating applications, such as for the generation of electrical power.

Abstract: Described herein are linear receivers for use in concentrating solar collection applications. For example, linear receivers incorporating a volume displacement element within an internal volume of a linear solar radiation absorbing element are provided. The volume displacement element provides, for example, enhanced heat transfer characteristics between the absorber element and the heat transfer fluid, efficiency improvements associated with maintaining a position of the linear receiver at an optimal location for absorbing concentrated solar radiation and/or the ability to recover the linear receiver from a freeze event. Also provided are methods for making a linear receiver, methods for collecting concentrated solar radiation, methods for recovering a linear receiver from a freeze event, methods for improving overall receiver efficiency, such as by reducing bowing/sagging of the receiver element, and methods for reducing a circumferential temperature distribution of the absorber element.

Abstract: A space frame having a high torsional strength comprising a first square bipyramid and two planar structures extending outward from an apex of the first square bipyramid to form a “V” shape is disclosed. Some embodiments comprise a plurality of edge-sharing square bipyramids configured linearly, where the two planar structures contact apexes of all the square bipyramids. A plurality of bridging struts, apex struts, corner struts and optional internal bracing struts increase the strength and rigidity of the space frame. In an embodiment, the space frame supports a solar reflector, such as a parabolic solar reflector. Methods of fabricating and using the space frames are also disclosed.

Abstract: A rotational system is provided for controlling rotation of one or more solar collectors to track the movement of the sun, to automatically keep the collectors locked in stow position during high wind conditions, and advantageously also to prevent damage to the rotational system due to high pressures caused by high temperature conditions. The system utilizes a bi-directional hydraulic rotational actuator hydraulically connected to a control system. The actuator advantageously includes a system of helical gears and a piston, and the control system includes hydraulic lines equipped with check valves that prevent circulation of hydraulic fluid through the hydraulic lines and the actuator when backpressure is exerted in one of the hydraulic lines as a result of high wind force on the collectors. In addition, the control system advantageously comprises a pressure-relief system to prevent damage to the actuator during high temperature conditions.

Abstract: Described herein are solar reflectors which provide a low cost reflector construction that has a unique set of attributes: high solar reflectance, abrasion resistance, UV stability, mechanical integrity, and flexibility. The abrasion resistance is enabled through incorporation of an abrasion-resistant coating into a polymer film metal mirror construction. Methods of using the solar reflectors in solar concentrating applications are also provided.

Abstract: Provided herein are solar collectors having reflective sheets which are slidably insertable and/or removable for quick installation, construction, removal, repair, and/or replacement. Also provided are solar collectors having reflective sheets under tension. Further provided are methods for constructing solar collectors. In another aspect, provided herein are guide rails for guiding and/or retaining slidably removable reflective sheets and holding the reflective sheets in a prescribed shape.

Abstract: Provided are reflective thin film constructions including a reduced number of layers, which provides for increased solar-weighted hemispherical reflectance and durability. Reflective films include those comprising an ultraviolet absorbing abrasion resistant coating over a metal layer. Also provided are ultraviolet absorbing abrasion resistant coatings and methods for optimizing the ultraviolet absorption of an abrasion resistant coating. Reflective films disclosed herein are useful for solar reflecting, solar collecting, and solar concentrating applications, such as for the generation of electrical power.

Abstract: A space frame connector is provided for attaching an oblique strut tube to an axial chord of a space frame. The space frame connector includes a collar adapted to fit over an axial chord. The collar is equipped with one or more attachment flanges. The space frame connector also includes a strut tube having an extrusion flange formed in at least one of its ends. The extrusion flange is made up of two parallel leaves that define a slot between them. The slot is sized and shaped to fit over an attachment flange on the collar that is positioned over the axial chord. The extrusion flange can be formed using simple press and punch tools. Space frames used to support solar energy collector arrays can be assembled in the field, including formation of the extrusion flanges on the oblique strut tubes, or multiple strut tubes can be attached to axial chords and compactly packed and transported to the field for use in constructing space frames, for example for supporting large parabolic trough solar collectors.

Abstract: Provided herein are solar collectors having reflective sheets which are slidably insertable and/or removable for quick installation, construction, removal, repair, and/or replacement. Also provided are solar collectors having reflective sheets under tension. Further provided are methods for constructing solar collectors. In another aspect, provided herein are guide rails for guiding and/or retaining slidably removable reflective sheets and holding the reflective sheets in a prescribed shape.

Abstract: A solar collector tracking system is provided for maintaining orientation of multiple solar collectors to the sun to provide optimal focusing of solar radiation on a receiver. The system includes a local controller circuit board that contains a sun-tracking algorithm to control the movement of multiple solar collectors to keep them optimally focused on the sun. The system also comprises a separate motor controller for each collector in data line connection with the local controller, and a motor for each collector in power connection with its motor controller. This isolates the local controller from the motor and protects the circuit board against power surges. The local controller allows effective field maintenance using field-replaceable components. Its circuit board is preassembled in a rugged, weather-proof cabinet to minimize the time and work required to prepare and install it in the field. The typical service life of this durable local controller is expected to be 30 years.

Abstract: Provided herein are linear solar reflectors and collectors, and methods of efficiently constructing such reflectors and collectors. The reflectors are made using reflective laminate sheets, which can be reinforced by tension-bearing strips. Methods and apparatuses for installing the sheets from a roll dispensing the sheets carried on a deployment vehicle are disclosed, as well as methods and apparatuses for assembling and constructing various collector components, methods and apparatuses for tensioning the reflective laminate sheets, methods and apparatus for passively changing the focal length of the reflectors while controlling their movement to track the sun, and methods and apparatuses for compensating for temperature changes in system components for moving the collectors, are provided.

Abstract: A rotational system is provided for controlling rotation of one or more solar collectors to track the movement of the sun, to automatically keep the collectors locked in stow position during high wind conditions, and advantageously also to prevent damage to the rotational system due to high pressures caused by high temperature conditions. The system utilizes a bi-directional hydraulic rotational actuator hydraulically connected to a control system. The actuator advantageously includes a system of helical gears and a piston, and the control system includes hydraulic lines equipped with check valves that prevent circulation of hydraulic fluid through the hydraulic lines and the actuator when backpressure is exerted in one of the hydraulic lines as a result of high wind force on the collectors. In addition, the control system advantageously comprises a pressure-relief system to prevent damage to the actuator during high temperature conditions.

Abstract: A space frame connector is provided for attaching an oblique strut tube to an axial chord of a space frame. The space frame connector includes a collar adapted to fit over an axial chord. The collar is equipped with one or more attachment flanges. The space frame connector also includes a strut tube having an extrusion flange formed in at least one of its ends. The extrusion flange is made up of two parallel leaves that define a slot between them. The slot is sized and shaped to fit over an attachment flange on the collar that is positioned over the axial chord. The extrusion flange can be formed using simple press and punch tools. Space frames used to support solar energy collector arrays can be assembled in the field, including formation of the extrusion flanges on the oblique strut tubes, or multiple strut tubes can be attached to axial chords and compactly packed and transported to the field for use in constructing space frames, for example for supporting large parabolic trough solar collectors.

Abstract: A solar collector tracking system is provided for maintaining orientation of multiple solar collectors to the sun to provide optimal focusing of solar radiation on a receiver. The system includes a local controller circuit board that contains a sun-tracking algorithm to control the movement of multiple solar collectors to keep them optimally focused on the sun. The system also comprises a separate motor controller for each collector in data line connection with the local controller, and a motor for each collector in power connection with its motor controller. This isolates the local controller from the motor and protects the circuit board against power surges. The local controller allows effective field maintenance using field-replaceable components. Its circuit board is preassembled in a rugged, weather-proof cabinet to minimize the time and work required to prepare and install it in the field. The typical service life of this durable local controller is expected to be 30 years.

Abstract: A method is provided for retrofitting an existing combined cycle power plant to generate renewable electricity and decrease the power plant heat rate using solar energy. The method is applied to combined cycle power plants that are equipped with an oversized heat recovery steam generator (HRSG) and steam turbine system to accommodate duct burners or other means of providing additional steam to the steam turbine. The method involves retrofitting a plant with a solar energy collection system to produce solar steam for use in the steam cycle portion of the combined cycle power plant. The solar energy collection system is designed to deliver thermal energy to the existing, oversized and/or underutilized HRSG and steam system capacity in the combined cycle power plant.