Optimized truss foundations, adapters for optimized truss foundations, and related systems and methods
An A-frame-shaped truss foundation system for a single-axis tracker with a bearing assembly sitting atop a pair of adjacent angled truss legs joined together with an adapter so that the axis of rotation of the tracker is aligned with a work point of the A-frame. Several such foundation systems are arranged along a North-South row to support a tracker torque tube.
1. A bearing adapter for joining truss foundation components supporting a single-axis tracker, the bearing adapter comprising:
a main body portion;
a bearing for receiving a rotating member, the bearing having a substantially circular bearing opening;
a bearing cap that attaches to the main body portion to rotatably capture the rotating member within the bearing; and
a pair of connecting portions extending from the main body portion and oriented at opposing angles to join a pair of adjacent truss legs so that an axis defined by each leg points at a common work point positioned at the approximate center of the circular bearing opening.
2. The bearing adapter according to claim 1 , wherein the pair of connecting portions are separated by an angle in a range of more than 35-degrees up to 70-degrees with respect to the common work point.
3. A foundation system for a single-axis tracker comprising:
a pair of elongated truss legs, each leg comprising a screw anchor and an upper leg portion that are joined together at their respective ends to define a substantially common axis;
an adapter having a main body and a pair of connecting portions projecting away from the main body and spaced apart by an angle in a range of more than 35-degree up to 70-degrees for joining a free end of each truss leg to form an A-frame-shaped truss structure; and
a bearing for receiving a rotating component of the single-axis tracker and having a substantially circular bearing opening, wherein each substantially common axis of the pair of truss legs is oriented to intersect one another at the substantially circular bearing opening.
4. The system according to claim 3 , wherein the bearing has a lower portion built into the adapter main body and an upper portion joinable to the lower portion.
5. The system according to claim 3 , wherein the bearing is separate from and attaches to at least one planar support surface of the adapter.
6. A single-axis tracker comprising:
a plurality of truss foundations installed along a substantially straight row, each foundation comprising a pair of adjacent angled truss legs extending below and above ground that straddle the substantially straight row;
a plurality of adapters, each adapter joining one pair of adjacent angled truss legs to form one of the truss foundations so that an axis through each adjacent legs of the truss foundation point at a common work point of the truss foundation;
a plurality of bearings, each having a circular bearing opening; and
a rotating torque tube seated within the plurality of bearings, wherein the rotating torque tube defines a rotational axis for the single-axis tracker that passes through the work point of each truss.
7. The single-axis tracker according to claim 6 , wherein the pair of connecting portions are separated by an angle in a range of more than 35-degrees up to 70-degrees with respect to the common work point.
8. The single-axis tracker according to claim 6 , wherein each truss leg comprises an upper leg portion coupled to screw anchor to substantially extend a main axis thereof.
9. The single-axis tracker according to claim 6 , further comprising a plurality of photovoltaic modules attached to the torque tube.