opus ARCHITEKTEN BDA
www. opus-architekten. de
194 opusHouse I Darmstadt | Germany | Fig. 1 above | Fig. 2 opposite
The design team employed a mainly passive strategy towards the goal of achieving an energy efficient development. A triple glazed facade with krypton filled cavities ensures the high insulation values of the building’s envelope.
The internal environment is controlled zonally by each tenant via an adjustable ventilation system, complete with heat recovery unit to mitigate energy loss. A ground heat exchanger provides additional temperature balancing. If heat energy is required, the air temperature can be raised and controlled by a minimised gas calorific value thermostat.
To supplement this strategy, the new sloping roof is covered with both solar thermal and photovoltaic panels. The solar thermal units warm the domestic water and support the heating system. Energy costs for opusHouse are reduced by feeding the energy from the photovoltaic units into the public network. The detailed systems are illustrated on the architect’s schematic drawings (Fig. 11, Fig. 13).
The construction details and colouring of the pitched eco-roof were carefully considered to blend with the existing roofscape of the perimeter block (Fig. 4, Fig. 12). Rainwater falling onto the building is collected and stored in a cistern for re-use in flushing toilets or garden watering.
Inside the building, the white finishes to walls and ceilings maximise the natural daylight provided by the glazed external walls and clerestory windows. A contemporary, engineered finish to the fixtures, flooring and staircases completes the transformation from an Empirical cellular layout, to 21st century, open plan, flexible accommodation (Fig. 5, 6, 7, 8, 9,10).
The bold modernisation of the streetscape is tempered to a certain extent, as opusHouse provides mirrored reflections of surrounding properties on its glazed, faceted frontage (Fig. 6). Furthermore, the tree filled open space in the centre of the block is enveloped and preserved by the closure provided by the scheme (Fig. 4).