Reliable movement with igubal pillow block bearings in solar trackers

The company Axiom Research Labs in Bangalore has developed an automated modular single-axis solar tracker system (SPV system) for use on roofs and in solar parks. By converting existing fixed installations to the tracker system "LEXSYS", more energy can be generated in less space for Indian residential, commercial and industrial needs. To ensure that the daily tracking movement of the solar units works perfectly, the company relies on our robust igubal ® polymer-pillow block bearings from the ESQM series - a "fit-and-forget" solution, as they are maintenance-free over their entire service life of 25 years.

Application Overview

What was needed: pillow block bearing for the bearing of square profiles that support the solar modules
Requirements: low-friction, dry-running, UV-resistant, corrosion- and maintenance-free
Industry: Renewable energies, solar technology
Success for the customer: igubal® ESQM-pillow block bearings with a guaranteed service life of 25 years are the perfect alternative to metal bearings that require regular lubrication/maintenance and have a corrosion problem. The robust solid plastic spherical plain bearings with low-friction spherical ball compensate for misalignment and enable permanent smooth movement without lubrication, corrosion and maintenance. Thanks to their split design, they are quick and easy to install.

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Problem

Each module of the tracker system can consist of 9 or 18 units of 540-560 watt panels, which have an output of 5 or 10 kW respectively. To support the horizontal square profiles that carry the solar panels, the designers were looking for suitable bearings (two for the 9-panel units and three for the 18-panel units).

The environment is a challenge for the bearing, as the system is exposed to high temperatures in summer, the effects of wind and rain as well as dirt and dust. Withstanding these conditions was one of numerous other requirements for the bearings: they had to withstand the high load of the entire tracking system - consisting of the panels, their supports and a corresponding counterweight - and at the same time have a low coefficient of friction. They should be spherical bearings that can absorb some axial loads, enable low-noise operation without torque fluctuations and have a service life of 25 years. All this ideally without lubrication and maintenance.

Solution

The engineers initially considered lubricated metal and composite plain bearings, but then found the technically best and most cost-effective solution at igus®: igubal® pillow block bearings from the ESTM series, which were specially developed for single-axis solar tracker systems. They consist of a housing made of igumid® G, a particularly robust, long fibre-reinforced polymer, and a very low-friction iglide® J4-spherical ball.

The service life of the bearing reached 72 years at a load of 1.5 tons in the igus® test laboratory, simulated over time. Therefore, igus® guarantees a service life of 25 years. The cost-effective pillow block bearings are UV-resistant, corrosion-free and require no lubrication, which makes them insensitive to dirt and completely maintenance-free. They also enable self-aligning, e.g. for uneven surfaces, and are quick and easy to install thanks to their two-part design. A true "fit-and-forget" solution with which Axiom Research Labs is very satisfied.

As part of a demo pilot project, Axiom Research Labs in Pavagada in the Indian state of Karnataka successfully converted around 140 kW of an existing system to igubal® ESTM-bearing.