How this glazed modern building gained planning approval in this stockbroker-belt town is a mystery, but after 13 months on site the £16.75m building is taking shape at the top of Cockshot Hill on the edge of town. And, by June, more than 500 Canon employees will be enjoying splendid views over Reigate.
Designed by David Richmond & Partners, based in London's trendy Clerkenwell area, the office consists of a two-, a three- and a four-storey block linked together. The blocks have all the usual trappings of low-energy design: exposed concrete soffits to soak up excess heat during the day and release it at night; fully glazed facades to maximise natural daylight; window louvres to reduce solar gain; fully openable windows; and a building management system that automatically opens the windows at night to reduce the building's summer temperature; and glazed atria that provide chimney-effect cooling.
But the real advance at Reigate is the building's photovoltaic system. Instead of using bulky, glass-based panels, main contractor Wates is installing, for the first time in the UK, Canon's new proprietary thin-film photovoltaic roofing.
The system comprises a foil of silicon-based cells that can be easily integrated into traditional roofing systems. The foil can be laminated on to flat roofing, metal-backed "shingles" or – as at Reigate – the metal trays used in standing-seam roofs.
At the Canon HQ, the metal trays are installed on pitched roofs built with timber trusses, insulation and battens. The steel trays are simply nailed back to the battens. Electric cables run from the top and bottom of each tray and are linked in series to complete a circuit to batteries and inverters that make the electricity usable.
The 580 maroon-and-grey panels are installed in banks of 10 on the south-facing roof slopes of the building. When running at full capacity, the panels will provide 80 W/m2. This compares with 120-150 W/m2 for traditional panels. However, it has two advantages over traditional systems: it is cheaper to produce and is lighter. Its lighter weight means that loadings are reduced and structural costs therefore lower. Canon's system costs £366/m2 installed and weighs just a few kilos per square metre. Traditional panel-based systems cost more than £600/m2 and weigh 17.5kg/m2.
The leap in performance is because of a new production process based on the technology that Canon uses to make photocopiers. Traditional cells are made from crystalline silicon. The crystals grow slowly (and expensively) in the carefully controlled conditions needed to maintain the purity of the silicon. Canon's new process involves sandwiching cheaper non-crystalline silicon between two layers of a material that is usually used to make semiconductors. Experts claim that the production process is 10 times faster and uses 150 times less silicon than crystalline silicon panels.
Thin-film-based products also provide maintenance and aesthetic improvements compared with glass-panel-based products. The thin-film products are practically unbreakable – unlike their glazed counterparts – and do not reflect light into neighbouring buildings.
Thin-film technology is a major leap for the economic viability of photovoltaics. It is estimated that development of thin films in the next decade could see panels that are able to pay for themselves over the lifetime of a building, which is not currently the case.
Despite the good news, Canon is being cautious about promoting its invention. The panels have been used in Japan, but there are no firm plans yet for a UK launch, even though rival products are being developed by Solarex Corporation of Pennsylvania and United Solar Systems of Michigan. And all three want a big slice of government-funded programmes for photovoltaic roofs in Japan and the USA – but none wants a high profile for its products until they are working at maximum efficiency.
