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 moderately sloped legs that translate lateral loads into tension and compression without substantially increasing the magnitude of the lateral load force while optimizing material usage. Several such truss foundation systems are installed in a row to support a torque tube of a single-axis solar tracker. An adapter joins ends of adjacent upper legs and separates the truss legs by an angle more than 35-degrees up to 70-degrees. In some cases, the adapter may have an integrated bearing.
1. A truss foundation comprising:
a pair of angled truss legs driven into a support medium and extending upwards; and
an adapter joining the pair of truss legs, the adapter comprising a pair of opposing connecting portions, each connecting portion received in one of the truss legs of the pair so as to separate the truss legs by an apex angle in the range of 35-degrees up to 60-degrees, and a bridge section between the pair of opposing connecting portions having a bearing positioned at an approximate center of the bridge section, the bearing receiving a bearing pin suspending a single-axis tracker torque tube, the adapter defining a pair of opposing spaces on either side of the bearing that limit a range of motion of the torque tube.
2. The truss foundation according to claim 1 , wherein each truss leg comprises a screw anchor component driven into the support medium, and an upper leg portion attached to an above-ground of the screw anchor component at a lower end.
3. The truss foundation according to claim 2 , wherein one of the connecting portions is received in an opposing upper end of one of the upper leg portions to complete the truss foundation.
4. The truss foundation according to claim 1 , wherein each screw anchor is driven at an angle with respect to plumb on opposing sides of a North-South oriented single-axis solar tracker row.
5. A single-axis solar tracker comprising:
a plurality of truss foundations, each one of the plurality of truss foundations comprising a pair of legs extending below and above ground that are joined above ground with an adapter having connecting portions oriented to space the pair of legs apart at an angle α, where 35-degrees<α≤70-degrees and an integral bearing;
a bearing pin seated in each bearing; and
a torque tube suspended from the bearing pin, rotation of the bearing pin causing an orientation of solar panels of the single-axis tracker to move as the torque tube sweeps through an arc limited by the adapter.
6. The single-axis tracker according to claim 5 , wherein each pair of truss legs straddles a North-South oriented row of the single-axis tracker, and the bearing of the adapter is oriented substantially above the North-South oriented row.