Self-ballasted heliostat with suspended mirror assembly

#The invention generally pertains to a heliostat device for capturing solar energy. In particular, the invention relates to a mirror or photovoltaic panel suspended from a tripod frame for tracking the sun for purposes of converting the sunlight to useable energy.

#Conventional heliostats are prohibitively expensive to build and install. These conventional heliostats include mirrors or photovoltaic panels, which can experience extreme forces in windy conditions. To withstand the wind loading, conventional heliostats are generally constructed from structural steel and anchored into the ground with posts and concrete. Steel, however, is a relatively expensive building material, and the labor cost to drill and set posts is comparable to the price of the heliostat itself. There is therefore a need for a cost-effective heliostat design that is also self-ballasting and wind-resistant.

#The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

#The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, and in which:

#FIG. 1 is a perspective view of an example heliostat, in accordance with a first embodiment;

#FIG. 2 is a top view of the heliostat, in accordance with the first embodiment;

#Illustrated in FIGS. 1 through 6 is a first embodiment of an example heliostat 100. The heliostat 100 includes a frame 101 with multiple legs, an optical assembly, and a plurality of wires or cables. The wires are configured to suspend the optical assembly from the frame, and are also configured to prevent the optical assembly from moving laterally. The optical assembly is able to pivot about a pitch axis and roll axis under the control of a plurality of actuators that determine the tension in the wires. In the preferred embodiment, the optical assembly includes a mirror for reflecting sunlight to a receiver tower, although the optical assembly in other embodiments may optionally include a photovoltaic (PV) panel.

#The frame 101 includes a plurality of leg members 102A, 102B, 102C with footings 106, preferably in the form of a tripod. The heliostat is self-ballasting so each footpad 106 sits on the ground without any anchors, stakes, bolts, or foundation. The leg members 102A, 102B, 102C are also rigidly affixed to top rails 104 configured to form a triangle. The leg members and tops rails cooperate to provide stability while resisting movement, flexing, and torque.

#The heliostat 100 includes a plurality of suspension wires 130A, 130B, 130C or other flexible members that suspend the mirror assembly 120 from the frame 101. The arrangement of wires is also configured to inhibit (e.g., prevent) the mirror assembly from moving laterally or in a swinging motion. In the example embodiment, the wires connecting the mirror assembly 120 to the frame 101 are arranged in diagonal patterns to inhibit (e.g., prevent) side-to-side motion of the mirror assembly.