The building envelope is the central element in the exchange between interior and exterior. The façade and roof are active components of the building’s energy supply concept: the solar thermal collectors installed as a parapet wall and on the roof areas supply heat for water and heating. Photovoltaic modules in the balcony balustrades generate electricity from sunlight. This simple yet clever concept is based on an elaborate system and a fully developed technology. In part, vertically irrigated trellis elements are hung in front of the garden-like balconies. During the warmer months, the climbing hydrangea planted in these elements provide shade for the outdoor areas and cools the immediate surroundings.

PCM curtain

Behind the large-scale glazing facing south, PCM curtains are additionally used in the interior spaces. These curtains were developed as a prototype in a cooperative design and production process for the building on the IBA Hamburg site. PCM stands for Phase Change Materials, which are substances that can store and later release heat in a latent form by changing their state. In the winter months, the curtains absorb the heat of the low sun and release it into the rooms at night. This enhances the thermal comfort along the extensive glass areas. The prototypes will be tested as part of the building’s monitoring in 2013/2014.

PCM is also used as a central energy storage system for excess heat from the solar thermal energy system. Additionally, the residential building is connected to the public power grid and the Energieverbund Wilhelmsburg network. The non-storable surplus energy from the house’s own energy generation is fed into the grid. During prolonged cold periods, the Energieverbund Wilhelmsburg energy network ensures the building’s heat supply. The energy concept is based on decentralised supply strategies and makes an important contribution to the gradual transition to renewable energy sources.