Retrofitting Europe's older building façades

The European Union is looking to create a "universal envelope" to make old buildings use less energy.
13 February, 2017
Aluminium frames play a key role in building more energy-efficient buildings in Europe.
As European countries move forward in planning for a sustainable future, they are confronted with the challenge of how to improve efficiency in older housing stock. It's a daunting task, because more than 40 percent of the buildings across member nations were built before 1960.

For economic and cultural reasons, it's simply not feasible to replace them. The old architecture didn't have the energy efficiency technologies needed today, and a study earlier this decade found precious few had been retrofitted.
Adding to the challenge is the vast range of climates across the EU, which demand different solutions in Spain or Italy than one might see in Finland, where thermal building requirements began more than 40 years ago.

Solving the climate puzzle for more than 500 million European residents is the task for the "Breakthrough Solutions for Adaptable Envelopes in Buildings" project, which understandably enough goes by the shorter BRESAER acronym. The EU-funded initiative focuses on technologies to improve a building's exterior envelope, using products and materials that can be adapted to a standardized frame.
Those frames are made of lightweight, durable aluminium, making them easy to manufacture, ship and assemble, but also modular enough to work with the solutions most appropriate for any specific site. The emphasis is on wall insulation, windows and roofs with integrated solar and thermal solutions – as well as natural ventilation and other techniques – relying on the overall framing to lower energy usage.
Basically, the standard aluminium grid is laid out across the rooftop and exterior façade, and materials for that building are attached. Solutions include a combined solar thermal and photovoltaic panel envelope; dynamic louvered windows with airtight seals and insulated solar blinds; and insulation or ventilated panels, all of which can be combined with other components for that climate's best answer.

The project seeks to apply cutting edge technologies, including nanocoatings, in sequences that begin with the existing exterior and traditional insulation layer. The "universal façade" frame is then affixed, with the new solutions added. They are also designed so that access to the original building exteriors, for maintenance and necessary repair of the existing structures, is made as easy as possible.
BRESAER is testing its solutions in five countries, with real-world applications on real buildings. The Turkish Ministry of National Education, one of the project partners, is home to a four-story building in Ankara that is testing the concept. By reducing the demand for heating and cooling, and adding some renewable features, the 1800-square-meter building is expected to become a near-zero building, defined as total consumption of less than 60 kWh/m2 per year, with a payback time of seven years.
Four other "virtual demo" buildings across Europe were chosen because they were built before the Energy Performance of Buildings Directive requirements for the EU were enforced, and therefore are retrofit candidates. The virtual sites – in Spain, France, Poland and Norway – all reflect different climate zones, and they were selected because they include different types of buildings and uses. For these sites, too, a customized energy envelope is configured and tested with an ROI in seven years as target.

Researchers at BRESAER also are working on building energy management systems, using algorithms to evaluate weather models and simulations to best evaluate energy performance. These are designed for humans to interact with the system, while automation better calculates the optimal energy usage.
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