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 system for single-axis trackers comprising:
a pair of truss legs driven partially into underlying; and
an adapter for joining the pair of truss legs to form a truss foundation with the ground, wherein the adapter comprises a main body portion, a bearing support portion above the main body portion for supporting a tracker bearing assembly, and a pair of connecting portions extending away from the main body portion for connecting to respective ones of the truss legs so that the pair of truss legs are separated by an apex angle α, where 35-degrees <α≤70-degrees.
2. The truss foundation system according to claim 1 , further comprising a bearing assembly having a cylindrical bearing portion for receiving a rotating member.
3. The truss foundation system according to claim 2 , wherein the bearing assembly is built into the adapter.
4. The truss foundation system according to claim 3 , further comprising a bearing insert in the cylindrical bearing portion.
5. The truss foundation system according to claim 2 , wherein the bearing assembly is attached to and supported by the adapter.
6. The truss foundation system according to claim 2 , wherein the rotating member is a tracker torque tube.
7. The truss foundation system according to claim 2 , wherein the rotating member is a bearing pin.
8. The truss foundation system according to claim 7 , further comprising a torque tube suspended from the bearing pin.
9. A single-axis tracker comprising:
a torque tube;
a plurality of solar panels attached to the torque tube;
a plurality of bearing assemblies supporting the torque tube;
a plurality of plurality of truss foundations wherein each truss foundation comprises a pair of adjacent legs extending into underlying ground; and
a plurality of adapters joining each pair of adjacent truss legs, each adapter supporting one of the bearing assemblies and having a pair of connecting portions that separate each truss leg of the pair by an apex angle α, where 35-degrees <α≤70-degrees.
10. The single-axis tracker according to claim 9 , wherein the bearing assemblies and adapters are components of a single structure.
11. The single-axis tracker according to claim 9 , wherein the bearing assemblies are attached to and supported by respective ones of the adapters.
12. The single-axis tracker according to claim 9 , further comprising a gap between adjacent solar panels greater than a width of each adapter at least location along the torque tube supported by one of the truss foundation, the gap preventing mechanical interference between the plurality of solar panels and plurality of truss foundations.
13. The single-axis tracker according to claim 9 , wherein each bearing assembly comprises a bearing supporting the torque tube so that the torque tube may rotate about its own axis.
14. The single-axis tracker according to claim 9 , wherein each bearing assembly comprises a bearing supporting a bearing pin from which the torque tube is suspended.
15. An adapter for joining a pair of legs of a truss foundation system comprising:
a bridge portion having a bearing that defines a rotational axis that is transverse to a width of the bridge portion;
a rotating member seated in the bearing and
a pair of connecting portions for joining the pair of legs to form a truss foundation so that the pair of truss legs are separated by an apex angle α, where 35-degrees <α≤70-degrees, wherein
the pair of connection portions are substantially aligned about opposing sides of the rotational axis.
16. The adapter according to claim 15 , wherein the rotating member comprises a bearing pin seated in the bearing.
17. The adapter according to claim 16 , further comprising a section of torque tube suspended from the bearing pin.
18. The adapter according to claim 15 , wherein the connecting portions extends from respective sides of the bridge portion.