Multifunctional glass membranes

Although there are a number of definitions around, the overarching concept of zero-energy buildings is that the building produces as much in renewable energy as the energy it consumes. Much of a building's energy consumption powers heating and cooling needs, so windows are an important target of energy-saving campaigns.

Novel insulated glass units under development within the EU-funded project MEM4WIN target significant weight, heat loss and cost reductions with modular solutions for energy harvesting. The smart window concept exploits ultra-thin glass membranes in a quadruple glazing to yield frameless windows that can be opened. The insulated glass unit already achieves its targeted level of heat transmission and optimisation is ongoing. The window is expected to cut weight and heat loss in half compared to other solutions.

Low-cost ink-jet printed organic photovoltaics and integrated solar thermal collectors will enable energy harvesting for power generation and hot water, respectively. Replacing expensive materials like indium titanium oxide and silver with graphene and exploiting cost-effective processing such as inkjet printing is expected to lower fabrication costs by about 20 %.

Scientists have established the processes to produce transparent graphene contacts. The organic photovoltaics are also ready for printing and lamination of modules. A solar thermal collector has already been integrated in an insulated glass unit. Finally, production of the movable micro-mirror arrays that will control incident energy for optimised energy efficiency is ready to start. The system will enable transmission between 75 % and 2 %.

MEM4WIN's advanced smart windows for building facades could help Europe's buildings achieve zero net emission status. Given that buildings contribute to approximately 40 % of Europe's overall energy consumption and close to 40 % of its emissions, the project could have invaluable benefits.

Commercialisation of the technology will slow global climate change and help meet energy challenges. Importantly, at a time of difficult economic crisis, it will also contribute to a leadership position for the EU in a market poised for tremendous expansion.