Solar photovoltaic firm Heliatek GmbH and Reckli GmbH, a maker of elastic moulds for concrete building facades to enable vertical concrete walls of buildings to become highly efficient solar energy harvesters by integrating Heliatek's organic solar panels directly onto concrete façade blocks. This new Building Integrated Photovoltaic (BIPV) solution will combine energy harvesting to reduce a building's carbon footprint with a discrete and more aesthetic appearance.
Heliatek's organic photovoltaic (OPV) technology is suited to this application as it is ultra-light, ultra-thin, and ultra-powerful, and harvests the sun's energy at peak efficiency across a ange of real world conditions for more of the time than traditional solar technologies. A major problem with conventional solar panels is that their efficiency drops off with every degree in temperature gained. Heliatek's solar technology, in contrast, is unique in that the efficiency of its organic photovoltaic modules remains constant up to 80 °C. This is also the reason why Heliatek's panels can be integrated onto the concrete without any need for ventilation.
Also, if the light intensity decreases, the efficiency of conventional solar panels decreases as well. Heliatek's panels are consistently efficient from full sun down to a tenth of full sun, such as on a cloudy day or when not directly facing the sun, only receiving indirect light. Heliatek estimates that, under real world conditions, the combination of these two factors - temperature independence and superior low light performance - will increase the specific annual harvesting yield of its panels by 10-20 % compared to conventional solar panels, depending on the location and orientation of the PV façade system.
"Today, vertical walls are rarely used for solar energy gathering, despite the fact that the vertical building walls offer a much larger installation area than roof tops that are the focus of today's solar building installations. Several factors such as unpleasant design, high system prices and limited performance potential are the reasons why vertical solar installations are not widespread," said Thibaud Le Séguillon, CEO, Heliatek.
"By 2020, an Euorpean Union directive will require new buildings to be nearly zero-energy as part of the drive to be green and so, having every wall being an active producer of solar electricity will be a major contributor to achieving truly green buildings. This solar technology has a truly green, zero environmental impact thanks to no toxic ingredients, non-toxic manufacturing with very little energy and material consumption, and ease of disposal as the modules are 99% PET plastic (the same plastic used in water bottles) with the rest also being harmless materials. Until now, architects have only had a limited choice of expensive and complex ways of adding solar harvesting to their building. This new BIOPV application will serve as a strong lever to start a new, truly green revolution in building design," said Bernd Trompeter, Managing Director, Reckli.
Architecturally, the new Heliatek and RECKLI solar concrete façade offers many benefits. The solar cells are deposited on a thin, flexible, lightweight plastic sheet so that there are no safety issues unlike with glass modules, which require very secure handling and installation, so that they do not fall. At only 0.5 kilograms per square meter, compared to conventional panels at 10 to 15 kilograms per square meter, structural support issues are minimized. Aesthetically, the BIPV modules can be added to a building's façade in non-intrusive ways and will be available in a variety of colors and dimensions to enable the architect to be creative with the external appearance of the building.
Heliatek uses a low temperature, roll-to-roll deposition process on plastic to manufacture solar panels, which will be highly cost competitive in mass production within a few years when the new solar façade modules will be available. The manufacturing technology is already in use in the OLED industry, providing Heliatek with proven, mass manufacturing machines and reliable processes that it can draw on to rapidly get to market with high volume production.