South Africa-based Cheshire Engineering director Joseph Steele is working to design and prove ‘The Kimberley Mechanism’, which he says is a cost-effective heliostat gearbox, which could be manufactured at a fraction of the current cost of conventional heliostat gearboxes. The country is looking to expand its renewable energy power generation, particularly with concentrating solar power (CSP), providing local companies the opportunity to expand as well within the sector.
A heliostat forms part of the CSP plant – it is the mirror-like device, placed in an array, which tracks the sunlight and focuses it towards a stationary central tower, to heat a medium such as molten salt or water. A large number of heliostats are required for a single CSP plant.
“Heliostats, which need to follow the sun, rotate slowly and precisely, requiring high ratio gearboxes – we are working between 8,000 and 60,000 to one,” explains Steele. It can be imagined that a mirror situated 1,200 meters away from a target needs a finer resolution, if it is not to skip the target under rotation, in other words a higher reduction, he continued.
“Photovoltaic cell receptors do not require the accuracy of CSP, and thus for this purpose, a cheaper, single axis mechanism driven by a constant speed motor would suffice for the directional tolerant photovoltaic cells,” Steele said.