On one of the main roads to the site of the Floriade Almere Expo 2022, the Dutch horticultural exhibition held in 2022 in Almere, Netherlands, one can find the new building of the Aeres University of Applied Sciences, a green education and knowledge institute. The building has been designed to provide a healthy, inspiring working and learning environment while itself being energy-neutral, climate-adaptive, green and circular. The building stands out with its extensive green facade.
Trigger and context
The design of the building reflects both the sustainable identity of the education at the Aeres University of Applied Sciences in Almere and the central theme of the world horticultural exhibition Floriade Expo 2022: ‘Growing Green Cities’. Being ‘Green’ was therefore an important design principle of the new building. On the one hand, incorporating sustainable, circular and self-sufficient solutions. On the other hand, it is literally a green school. A ‘green lung’ with different types of green walls, plants and trees, swings through the building like a landscape, from entrance to roof. The greenery stimulates the senses and in addition plays a role in education: students in Almere are conducting research into urban food supply and healthy living in a green city as also how the greenery in the school contributes to learning performance. The design, construction and management of the greenery are all in one hand.
Besides becoming a sustainable Floriade showcase, the new college had to be, above all, a place that students love to go to. The health and well-being of staff and students and the ease of use of the building therefore received a lot of attention in the design. Aeres is the first school in the Netherlands that received the Platinum WELL building standard certificate.
The building’s green concept was developed together with teachers and students. The students devised a bee ladder that was integrated into the facade.
The building was designed holistically. The designer of the greenery was involved in the design of the building at an early stage, as were the designers of other disciplines. This made it possible to realise all facets of sustainability in the building in a coherent manner.
Design and design issues
The new Aeres University of Applied Sciences building is smart with energy: depending on the position and orientation of the facades, these have different properties. For example, PV panels on the west side provide solar shading in addition to generating energy. The east side, facing the Floriade grounds’ tree garden, is completely green and changes colours with the seasons. The lively, nature-inclusive green roof is both a pleasant living space and an inspiring learning and experimentation area: a shade roof of semi-transparent PV panels protects the students from the sun and reduces the heating of the school.
The ample presence of living greenery has already a significant positive effect on the indoor climate. In addition, other relevant factors such as the entrance of daylight, ventilation, thermal comfort, acoustics, movement and the use of non-toxic materials have been optimised. Per room, users can control lighting, climate and shading themselves. Building performance is continuously monitored and controlled by an intelligent building management system. The inspiring interior furthermore reflects the educational vision and sustainability ambitions.
In line with the sustainable ambitions for the new college, various circular materials have been incorporated in the building, such as biocomposite cladding, concrete granulate, recycled wood for the grandstand steps, decking and outdoor furniture, and recycled metal studs for the interior walls. In turn, the demountable design itself enables future reuse of materials that were registered with Madaster.
The building produces more energy than it consumes. The Energy Performance Coefficient is negative. There are 400 semi-transparent solar panels on the roof and 300 panels against the facade. There is an automated building management system that regulates daylight and ventilation, ensuring minimal energy consumption. Heat and cold storage in the ground has been chosen for heating and cooling.
Green and water
To provide water to the ample greenery on the facade and roof, water storage has been built on the roof as well as under the building. Rainwater is directed to the plants under data-control.
As many plants as possible with the letter L were chosen for the façade, because the plots of the Floriade grounds each have a letter from the overarching Arboretum idea. The entire Floriade grounds then form a flower and plant library. From Aeres it was the wish to provide housing for as many insects and birds as possible. Together with teachers and students, the robust planting plan came about.
The collected rainwater serves as a heat/cooling buffer and is used to water the plants. This saves 50% of the drinking water normally needed for watering. 70% of the rainwater is used and 30% is drained with a delay: there is a water storage of 28,000 litres on the roof and of 59,600 litres under the building. Excess rainwater that cannot be stored in the buffers is discharged to the street. Note that in Almere, it is compulsory to store rainwater on the plot. The Floriade site does not have a rainwater sewer.
By choosing a modular system for the green facade, the plants could be planted in their containers already at the nursery as early as spring. The modules were hung on the façade with fully grown plants. The advantage of this system is that the plants have already rooted well when installed and plants could be replaced if necessary. A ‘bee ladder’, devised by the students under the supervision of an ecologist, was realised on the façade, leading the bees to the roof via the strategically placed assortment.
The roof is a meeting space and garden of which the design was based on supporting local biodiversity. Native plants were used and the roof garden substrate was adapted to better match the natural vegetation. There are six trees on the roof.
Tropical and subtropical plants were used for the indoor planting. A planted wall along the void stores rainwater to provide the plants with sufficient water. Various forms of indoor planting systems have been used.
Maintenance of the roof and façade greenery is similar to that of similar greenery at ground level. The façade is inspected every month. Twice a year, the façade is maintained using an aerial platform. Pruning is done and plants are replaced if necessary. The roof garden is checked every 3-4 weeks and seedlings are removed or plants replaced if necessary. The indoor planting is inspected once every month.
The main big lesson of this project is that such an integral project with substantial greening, a sustainable energy concept and the use of rainwater requires that the various professional disciplines work together from the start. These include the architect, the construction design engineer, the green planner, the building physicist, etc. For instance, the additional weight of the green roof must be taken into account and the fixing of the green façade must be considered. Plants have to be ordered on time; pre-cultivating the plants at the landscaper’s workshop in the trays that would be attached to the façade has ensured that the plants grew better and there was less failure.
Another lesson was that the basic idea of structuring the Floriade grounds as an arboretum with only plants in each quadrant with a name beginning with a certain letter, in the case of the Aeres University of Applied Sciences the letter L, was too compelling. It is better to choose plants that suit the location and environment; those plants are then most successful and therefore more sustainable and also make the greatest contribution to biodiversity. For example, six trees among which only one apple tree have been planted on the roof; the green planner would have liked to have planted more apple trees for biodiversity.
The construction cost of the green facade, green roof and indoor planting was about EUR 1,000,000 incl. 1.5 years of maintenance.
Interview with and material by Marc de Jager, The Royal Ginkel Group
Project book Aeres Hogeschool Almere ‘Built to let the city live’