Solar mirror film: A more efficient form of solar energy

International markets and consumers are increasingly demanding that businesses operate more responsibly and that their production processes have the smallest environmental impact possible. Conscious of this trend, four years ago the juice and wine export company Jucosol decided to seek out efficient renewable energy technologies for use in its business operations.

Initially, the company explored the use of solar energy in its facilities in San Felipe, in the Aconcagua Valley. Success in this endeavor was limited. As Christian Rey, General Manager of Jucosol explains, this was due to the project relying on flat collectors for capturing sunlight, which required not only a large area of land to operate but also a sizeable investment. The company itself sells 6,500 tons of concentrated wine juice per year, with annual sales of US$13 million.

Despite this initial setback, the company kept persevering. And then two years ago it contacted the multinational firm specializing in innovation, 3M, to investigate the possibility of using highly efficient parabolic collectors – which had, until that point, only been approved in the United States. Following numerous studies, a conclusion was reached that the technology was adequate for the company’s needs, given that it required a smaller area of land than traditional projects.  After a number of weeks spent on construction and an investment of US$500,000, this system – which is a pioneering one at the global level – began operating in June. The overall purpose of the system at Jucosol is to heat water in the company’s industrial boiler.

Occupying an area of 700m2, the facility provides the company with approximately 800 MW/hour per year. Rey notes that this will translate into savings of more than 10% of kilo calories of energy per year. It will also reduce diesel consumption by 78,000 liters, which in turn means generating 190,000kg less of CO2 per year. As such, the company’s overall environmental impact will be reduced in the process.

This is the first time anywhere in the world that a company has implemented the Large Aperture Trough (LAT) 73 system (developed by 3M and Gossamer Space Frames) at a commercial level. Using the technology of the parabolic trough solar collector, solar mirror film is utilized instead of the more commonly used glass, ensuring improved reflectiveness and light capture. There are currently two demonstration projects in the United States and another system under construction in Japan.

For Luis Lillo, Business Leader of 3M Purification INC at 3M Chile, the greatest asset of this system is its efficiency, as it uses fewer materials, up to almost 25% less. In fact, he says that to generate 10 MW with glass, 2,000 frames are required, compared to just 1,500 using film. Furthermore, less infrastructure and space are needed. Using glass, troughs can only reach up to 5 meters in size, whereas with film they can open to as much as 7.3 meters, thanks to their lighter support structures. In addition, their lighter weight means they can be manufactured faster and associated transport costs are reduced.  The flexibility of the film also allows additional benefits, including: solar radiation reaches interception levels of 99.3%; and a concentration range of 103 is achieved in the central absorber located in the structure where energy is concentrated. Figures such as these lend considerable support to the effectiveness of this solar energy system.

New projects

If everything goes according to plan, Jucosol intends to incorporate additional solar energy solutions into its business operations. Among their ideas is the instalment of a further eight parabolic trough solar collectors to generate steam and, eventually, in a third phase, install a turbine to generate electricity. Sustainable efforts such as these, says Christian Rey, will contribute to improved traceability of their products and less contamination – factors which are valued by customers and which also enable the company to access more environmentally-demanding markets.

 For 3M, who is responsible for developing the film, and Gossamer, which develops the support structures, growth projections in Chile are positive, especially in the agricultural and mining industries. As Lillo points out in relation to the mining industry’s high consumption of diesel, this fuel can be easily replaced by solar energy. Accordingly, rounds of meetings have already been held regarding potential business and in order to demonstrate, for the very first time, how the system actually works on-site.