The TU Wien (Vienna University of Technology): Award-Winning Plus-Energy Retrofit of a High-Rise Office Building

The Plus-Energy Office High-Rise Building of the TU Wien (Vienna University of Technology), completed in 2014, is the first example of a sustainable renovation of an office tower building, which generates more energy than it consumes. It is also a great example of successful interdisciplinary collaboration, simultaneous, integrated planning, as well as a well-developed usage concept.

In addition to drastically reduced energy consumption (by up to 88%), the building produces electricity directly through a photovoltaic system integrated into the facade and mounted on the roof and via energy recovery from the elevator. Energy recovered from the server’s waste heat is the main source of heating for the building.

This building proves that renovation with a plus-energy concept is not only technically possible but also commercially feasible.

Read the whole case study here.

The Aerem Factory: An Ecological Co-Designed Factory Building

The Aerem building in the South of France proves that also factories, which typically have a relative high carbon footprint, can reach positive energy standards. The building was constructed in 2018 and uses a modular steel structure as a basis which can be adapted and extended to adapt the factory for varying future uses.

The steel structure is insulated with locally harvested straw to further reduce the carbon footprint of the construction materials. The combination of steel and straw, used in an industrial context, is one of the key innovations in this project. Heating and cooling are provided by a geothermal heat pump system in combination with (high flow) night ventilation. Electricity is generated by photovoltaic panels on the roof.

The building was designed in close collaboration with its future occupants in order to understand and meet up with their functional needs. Special attention was paid to acoustic comfort, air quality and visual aspects to increase occupants’ satisfaction and well-being. The Aerem factory has won the low Carbon Prize of the Green Solutions Awards both in France and internationally.

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NEWTONPROJEKT Collective Housing: a Role-Model for Residential Positive Energy Buildings

Realised in 2018, the NEWTONPROJEKT in Berlin can be seen as a great model for the future of residential positive energy building (PEB) construction in Germany and elsewhere. Benefiting from attractive financing options for energy efficient buildings and applying a collective user-centric approach to property development, the building ensemble delivers not only more energy than it consumes but incorporates a host of environmental considerations.

NEWTONPROJEKT House 1, which is the focus of the case study, uses renewable and recyclable materials where feasible and its residents benefit from adaptable, accessible and comfortable apartment units. Moreover, sustainable mobility solutions have been incorporated in the design and the collaborative planning approach has created a stronger sense of community. A key success factor underpinning this project was the partnership with the local district heating network operator. Not only is renewably generated electricity exported to the grid during times of surplus, but also solar thermal heat can be fed back into the network. Such an integrated approach would greatly enhance the replication potential and broader adoption of PEBs in Germany and beyond.

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Powerhouse Kjørbo: Taking a Life-Cycle Approach to Positive Energy Buildings

Powerhouse Kjørbo is a renovation project of two former office buildings that were originally constructed in 1979. It was the first time that buildings were renovated to a positive energy building standard.

An important first step towards reaching this target was to reuse and select environmental friendly construction materials. In addition, a ground-source heat pump system was installed in combination with an efficient ventilation system.

Special attention was paid to visual comfort by maximising the use of natural daylight. The heavy concrete structure optimises thermal comfort as the thermal mass tones down temperature fluctuations. Powerhouse Kjørbo received great national and international attention from authorities, politicians and professionals.

The project demonstrates that the positive energy building concept is feasible even in colder climates, both in a commercial and environmental context.

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Passivistas: Transforming a 1960's residential building in Papagos, Greece

TheHouseProject demonstrates that even in economically difficult times retrofitting existing residential buildings so that they generate more energy than they consume is both financially and technically feasible.

Bringing together a team of experts and finding support from private sector partners as well as via crowdfunding, renovation works were carried out in 2015 and 2016 using materials and technologies available on the market. The cost for transforming the 125 m² two-level structure into a positive energy building (PEB) will be amortised in under seven years by energy savings.

The Passivistas team has made a great contribution to raising awareness and building capacities for PEBs with over 1,000 visitors taking part in open house events and seminars. Whilst the project already has great replication potential in Greece and beyond, scaling up the energy efficient renovation of residential buildings could be catalyzed further by tailored financial solutions, more ambitious regulations, and incentive schemes.

Read the whole study here.