Researchers at MIT and RWTH Aachen University in Germany have developed a design inspired by nature that cuts the amount of land required for a Concentrated Solar Power (CSP) farm, while increasing the amount of sunlight its mirrors collect.
The discovery originated with the development of a computational model at MIT to evaluate the efficiency of heliostat layouts. As designs were refined, the researchers noted a resulting highly efficient pattern had some spiral elements similar to layouts in nature; so they looked to nature for an even better arrangement.
The researchers discovered that by arranging heliostats, reflective mirrors that focus sunlight onto a receiver, in a pattern akin to the spirals on the face of a sunflower, they could reduce the array’s footprint by 20 per cent and increase its potential energy generation.
The land required by heliostats reportedly comprises around 33 per cent of the direct cost of most CSP plants.
The sunflower pattern allows for a more compact layout and also minimises shading and blocking of a heliostat by its neighbours – a common issue in traditional CSP fields.
The florets, small flowers that make up a sunflower head, are in a pattern known as a Fermat spiral and are angled at around 137 degrees – an angle emulated by the researchers in their trials.
With tumbling solar PV prices seriously challenging the CSP industry; the development will be welcome news to the concentrated solar sector.
In August last year, it was announced 500 megawatts of construction work at the massive Blythe solar farm would be switched from CSP to PV technology in order to make it a “more attractive prospect for financing from commercial banks”.
The research was carried out by MIT’s Alexander Mitsos, the Rockwell International Assistant Professor of Mechanical Engineering and Corey Noone SM ‘11, who collaborated with Manuel Torrilhon of RWTH Aachen. The researchers published their results in the journal Solar Energy and have recently filed for patent protection.