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Buildings account for around 40 % of energy consumption in Europe and one-third of carbon dioxide emissions. Older buildings are remarkably inefficient by modern standards and with 90 % of Europe’s buildings dating from before 1990 we have a long way to go to cut their use of energy.
“We are in a different situation compared to other parts of the world, as we already have a massive built environment,” says Giulia Barbano of UK-based Integrated Environmental Solutions and coordinator of the EU-funded RESSEEPE project. “We have a lot of existing buildings that perform quite poorly and we don’t have a large capacity for new construction.”
The 27 partners of RESSEEPE set out to tackle the large and complex problem of how best to upgrade existing buildings to cut their energy consumption at an acceptable cost. The focus was on public buildings, both to lead the way by demonstrating new approaches and to prove that renovation can be cost effective even in buildings that must remain open every day and even through the night.
Over a two-year period buildings at sites in Spain, Sweden and the UK were renovated with a combination of mainstream energy-saving technologies – such as external insulation, electrochromic windows, LED lighting and solar photovoltaic (PV) panels – and five innovative technologies, some of which are only now becoming commercially available.
Innovative solutions
The project team installed the technologies at five buildings: two hospitals in Barcelona, Spain, a school in Skellefteå, Sweden and two university buildings in Coventry, UK.
In addition to the use of already existing technologies, the project tested five innovative technologies.
- Aerogel-based mortars made with super-insulating lightweight porous granules were applied to the outer facade of buildings to reduce heat loss.
- Vacuum insulated panels (VIPs) consist of an evacuated core sandwiched between air-tight layers. They are not new but the project trialled a more efficient type made in standard sizes and encapsulated in polyurethane foam, making them easier to handle and install.
- Ventilated facades are commonplace in refurbished buildings but RESSEEPE used solar photovoltaic modules as the outer surface over an air gap and VIP insulation. The solar photovoltaic panels store surplus energy in batteries using supercapacitors to extend battery life.
- Solar thermal collectors, for water heating, were covered with an insulating plastic layer to boost their effectiveness in winter months.
- Phase change materials, which absorb heat as a room warms and release it as temperatures fall, were installed in tubes in ceiling voids to moderate room temperatures without the need for air conditioning.
“All these are solutions are easy to install,” says Barbano. “They don’t require complex interventions which is fundamental to maintaining these buildings in operation during the retrofit.”
Best practice handbook
Evaluation of the work shows that energy consumption of old buildings can be cut by a half with a well-designed mix of retrofitting solutions.
With energy renovation accounting for around 15 % of all construction activity, worth some EUR 186 billion in 2015, Barbano believes there is a large potential market for the solutions demonstrated in RESSEEPE.
The findings of the project are being disseminated with a best practice handbook and several other publications and videos.
“A public authority who’s working to refurbish their building can look at these and understand the pros and cons of the different technologies, potentially comparing them to different solutions and make an informed decision on how to move forward,” says Barbano.