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Viganella: solar power with a twist! Let there be light – and there is! by ROSS TESTER D eep in Italian Alps lies the tiny town of Viganella. It’s about as far north as you can get in Italy before you cross into Switzerland. But the Bishop who founded Viganella in the early 13th century made a fundamental error in siting the town. It didn’t occur to him at the time – midsummer 1217 – that the idyllic location between two streams near the bottom of a deep valley would also be the cause of eight centuries of winter misery. For most of the year, Viganella is beautiful. Picture postcard, even. But for 84 days in winter (November 11 to February 2) the village is completely in the shadow of a 1100m high peak to the south and receives no sunlight whatsoever. While that doesn’t translate to darkness, it does – or at least did – mean a gloomy existence, making Viganella very much less than ideal during winsiliconchip.com.au The concept is delightfully simple: place a mirror high enough up a south-facing mountain so that it can “see” the sun, normally hidden behind a tall mountain to the south. Angle the mirror so that it reflects the sun back down into the shadows and . . . ecco! (that’s Italian for voila!). But it took some seven years and 100,000 euros (approx. $AU165,000) to bring the concept to fruition. February 2007  11 For most of the year, Viganella is an idyllic place to live, nestled high in the Italian Alps (above). But come late November, it used to be plunged into gloom and perpetual cold until the sun reappeared in February – the most frustrating part was the brilliant sunshine only a couple of hundred metres away on the mountains above. ter. Temperatures plummeted, flowers died and laundry took an eternity to dry naturally, if at all. It seemed so unfair. The villagers could see brilliant blue sky above, could see the bright sunlight on the mountains overhead – yet they were destined to live in shadow. Most of the town’s 185 residents didn’t venture outside during the days of perpetual gloom. They re-emerged only for one of the town’s main festivals, held early February to mark the return of sunshine to Viganella. Many, especially the younger ones simply left town, leaving only the elderly behind. Fewer and fewer children were born, until Viganella faced the threat of extinction. Even the health of those residents that remained in Viganella suffered with a condition known as SAD – “Seasonal Affective Disorder”, whereby the lack of sunshine reduces a person’s production of melatonin, a natural hormone, making them depressed. Today, though, it’s different. While ever there is a cloudless sky, Viganella is bathed in sunshine for up to six hours each day. That mightn’t sound like much to plains dwellers but it certainly does to Viganellans! So what has changed? In a classic twist to the old proverb about moving Mohammed and mountains, Viganella resident – and now From the Viganella council’s files, this diagram shows the concept diagram for the heliostat system. The final execution looks slightly different . . . 12  Silicon Chip Mayor – Pierfranco Midali brought the sunshine to the village by erecting what is believed to be the world’s first, and only, heliostat (or mirror if you like) intended specifically for light. It’s mounted high on the 1100 metre Mount Scagiola on the northern side of the valley, catching the sun’s rays from the south and reflecting them back down into the depths of the valley – and Viganella. The village is illuminated (and warmed!) by the reflected sun rays for between five and six hours each day – assuming, of course, that the sun is shining! It’s centred on the town square or piazza. The villagers call the square “Il Cuore di Viganella” – the heart of Viganella. . . . and this is it, perched about 500m above the town on Mt Scagiola. The 5 x 8m mirror is made of steel and computercontrolled motors allow it to track the sun’s movement. siliconchip.com.au Viganellans waiting for the sun to, umm, rise? The mirror gives about 5-6 hours of sunlight in the village each day. The heliostat, made of steel, is about 40 square metres (8 x 5m). It tracks the sun’s progress across the sky with the aid of computer-driven motors so the sunlight is always aimed at the village. Architecht Giacomo Bonzani did some experiments in his back garden to prove the theory. And the mirror on Mt Scagiola is the end result. “On a clear day it produces five hours of sunlight in the piazza even in midDecember,” he said. “In theory, it could be snowing in the village but so long as the sun was out further up the valley, Power Supplies Here’s another view of the system on the mountain. Presumably this photo was taken during construction. Viganella’s piazza could have snow and sunshine at the same time.” The giant mirror was ferried to the site by helicopter and installed last November. A big inauguration party was held on December 17, close to the Winter Solstice. Residents wore sunglasses in commemoration of the event and the vision of their mayor. Midali, a former railwayman, took seven years to raise the 100,000 euros to bring the idea into reality, getting himself elected Mayor of in the process. Oscilloscopes RF Generators As this issue of SILICON CHIP goes to press, Viganella is in the old “gloom” period but latest reports have the residents – especially the elderly – sitting outside in Il Cuore di Viganella enjoying the winter sun and warmth. Interest in the Viganella sunshine project has come from many other similarly-affected villages in The Alps, on both sides of the Italian/ Swiss border. Mayor Midali might just have spawned a whole new SC industry! Frequency Counters Spectrum Analysers HAMEG Instruments have always been recognised for the consistent quality and nocompromise value of German engineering. And now the news is even better! With more new products, an attractive educational discount scheme and lower prices for 2007 you owe it to yourself to find out more. Call us please on 1-300-853-407 Test Equipment: Sales, Service and Calibration siliconchip.com.au 1-300-853-407 www.triosmartcal.com.au February 2007  13