Double-glazed windows could soon be green. Organic photovoltaics company Heliatek GmbH has announced that its transparent solar films could be applied in between the glass sheets of double-glazed windows, turning windows into solar energy harvesters.
Heliatek says the windows would look like tinted glass as the company’s vapour deposition technology allows for a homogeneous coating of the solar layer without any distracting patterns of irregularities. The transparency level, as well as the colour, can be adjusted to suit customers’ requirements.
Recently, Heliatek announced an agreement with Reckli, a manufacturer of elastic moulds for concrete facades, to integrate Heliatek solar films onto concrete building walls. The companies say this will enable vertical concrete walls to become solar energy harvesters without needing supporting structures or cooling mechanisms.
According to Dr Martin Pfeiffer, co-founder and CTO of Heliatek, the film’s low-light capabilities mean that the orientation and angle of the film is not critical and it maintains efficiency even when cloudy, north-facing (in the Northern Hemisphere) or in the morning and evening.
In its laboratories, Heliatek can produce a transparency level of up to 40% and hopes to increase this to 50% when the transparent solar films are supplied to the building industry in 2014. Independent testing confirms the company’s lab cells have an efficiency of 7% at a light transmission level of 23.5%.