5 original retrofit projects from around the world by the experts of tomorrow

At the international Solar Decathlon Europe competition, students compete in ingenuity to think about construction in a sustainable and inventive way. From Taiwan to Sweden, let’s focus on the most innovative projects of this edition!

Construction durable et inventive

Created in the United States in 2002, the Solar Decathlon is an international competition dedicated to energy-efficient housing. Based on the model of the World Fairs, students in architecture, electrical engineering or urban planning present a prototype of sustainable, passive, or bioclimatic housing using renewable energy.

Since its launch, the event has been held on different continents. In June 2022, the new edition of Solar Decathlon Europe is being organised in Germany, in Wuppertal. 18 university teams from 11 countries will submit urban renewal projects corresponding to one of these three issues:

  • the extension of a poorly insulated building often built shortly after the end of the Second World War with poor-quality materials
  • building on vacant spaces between two buildings to fill the space
  • raising the height of a building by adding one or more floors

In all cases, the aim is to increase the capacity of buildings while promoting energy and resource efficient solutions.

Selected from the 18 projects in competition, here are five innovative proposals imagined by the young generation of future sustainable construction professionals!

1 House For All (Taïwan)

The team: Team Transdisciplinary Design Innovation Shop (TDIS)

The school: National Yang Ming Chiao Tung University, Taipei

The project: With an average of almost 650 inhabitants per square kilometre, the island of Taiwan has an extremely high population density - more than twice that of the UK, and more than six times that of France. In this East Asian island country where 80% of the population lives in cities, every vacant lot in urban areas represents a valuable opportunity. This is particularly the case in Taipei, the island's political, cultural and economic capital, where almost a third of the population lives.

The 1 House for All project, presented by students from National Yang Ming Chiao Tung University, aims to be a more environmentally friendly alternative to traditional shop-houses. These mixed-use buildings of 4 or 5 floors usually have a shop on the ground floor for commerce and housing on the first floor. Designed as a modular construction that can be easily disassembled and relocated to a different place, this project for all generations of residents is based on three elements: its carbon neutrality, shared household electrical goods and a convivial space open to all. The aim is to develop social relations and mutual aid between generations while making the most of the available space.

More info: https://www.instagram.com/team.tdis.taiwan/

Col de l’Arzelier (France)

The team: Team Auvergne-Rhône-Alpes (Team AuRA)

The school: École Nationale Supérieure d’Architecture de Grenoble (and its partners)

The project: If you're going to renovate an existing building from top to bottom, you might as well tackle an abandoned building and bring it back to life. In mountainous areas, the number of such buildings is increasing as winter sports resorts are forced to close due to poor snow conditions. The AuRA team found a striking example 35 km from Grenoble, at the Col de l'Arzelier.

Located at an altitude of 1,154 metres, a typical old hotel from the 1970s, which has been closed for almost two decades, symbolises the consequences of climate change in this area. Committed to a resource protection approach, the students are relying in part on the reuse of materials to renew the building's insulation, an essential prelude to its reopening... but not as a hotel.

To rehabilitate this 2,500 m² building, the project plans to keep spaces open to the public on the ground and first floors, thought of as third places (café, workshops, etc.). The AuRA team advocates for ‘the revitalisation of rural communities as an alternative to the development of mega-cities’, without opposing the two: the notion of territorial balance is at the heart of its approach.

More info: http://team-aura.org/

The Cube (Germany)
Le cube

The team: LOCAL+

The school: University of Applied Sciences Aachen

The project: ‘We bring movement to your life!’ With this credo, the Local+ team sums up their amazing project. The concept is aimed at single residents who wish to live in a community. The solution they have come up with reinvents the concept of shared accommodation: it takes the form of a small, enclosed, private room measuring 4 square metres. A Cube, then. It contains a bed, storage space and a multi-functional table, while a lateral desk can be unfolded from one of the outer sides.

On each floor of the building, a flat occupies the entire space, without partitions. Instead of conventional rooms separated by walls for the flatmates, three Cubes are available per flat. Thanks to wheels, the cubes can be moved around the flat to suit the needs of the three residents. Like a Tetris game, the layout of the flat varies according to the time of day, with priority given to common space rather than individual space. Such an operation combines space saving and diversity of spatial configurations: the flat can become a studious coworking space during the day, a convivial place in the evening and then a dormitory at night.

More info: https://www.team-localplus.com/project

Ripple (Pays-Bas)



The team: VIRTUe

The school: Eindhoven University of Technology

The project: Like other teams participating in this edition of the Solar Decathlon, VIRTUe has designed its project for an installation in the event's host city, Wuppertal. More specifically, in one of its most famous places of conviviality, the ADA café, even if the sixty or so students in this multidisciplinary team insist on the transposable nature of their concept. Called ‘ripple’ in reference to the ripple effect, the project is intended to be the first stage of a progressive change in the neighbourhood in question. The idea is to increase the height of a public place (restaurant, shop) by adding a residential part with a roof terrace that is accessible from the street via an outdoor staircase. Residents can thus access certain parts of the building to discover its renovation and architecture, with the aim of instilling the same desire for change within their community.

Inside, conviviality is encouraged by a simple choice: the same kitchen equips two neighbouring flats, which are not separated by a corridor, as in a traditional building, but by a common room that encourages exchanges - and saves space. An intelligent electricity network called EQUI optimises energy production and consumption. EQUI's photovoltaic sensors automatically start appliance operation cycles at the sunniest time of the day.

More info: https://teamvirtue.nl/project/

C-Hive (Suède)

The team: Team Sweden

The school: Chalmers University of Technology, Gothenburg

The project: In the heart of the city of Gothenburg, the students of Team Sweden spotted a typical 1970s supermarket that was rather discreet. This was the ideal place to test their intuition: due to their size and age, this kind of soulless building will easily be suitable for renovations and changes of use in the medium term. The idea here consists of building a structure on the roof that will mix housing and workspaces. Called C-Hive, this extra height project must obviously consider several constraints such as the weight of the new structure, hence the choice of light materials.

The structure of C-Hive will be made out of wood but will also benefit from 3D cellulose printing. Through this revolutionary process developed at their university, students will be able to have reusable ‘printed wood’ parts designed to order. This resource will come from the recycling of waste from the Swedish forestry industry, which seems logical: the design of the building is inspired by trees, with clear references between walls and trunks, façade and bark, roof, and canopy. Team Sweden uses the plant metaphor to sum up their project: ‘like a mushroom sprouting from the ground, the new grows on top of the old’.

More info: https://www.c-hive.com/




All the other projects in the competition can be found on the Solar Decathlon website. As the name suggests, the Solar Decathlon is based on ten events, including architecture, engineering, energy efficiency, innovation, and financial viability. An international jury is responsible for selecting the winning team.


Credit : © SUM / SDE 21/22 ; © TDIS / SDE 21/22 ; © AuRA / SDE 21/22 ; © LOCAL+ / SDE 21/22 ; © SDE 21/22 ; © VIRTUe / SDE 21/22