Office Südwestmetall, Esslingen a.N., Germany

The new administration building of Südwestmetall in Esslingen has an innovative energy and comfort concept. The building's heat demand is covered by a groundwater heat pump with an open loop well system as heat source. A relatively constant groundwater temperature of approx. 12°C (53,6 °F) throughout the year and the low-temperature heating system lead to a high heat pump COP and thus to very efficient energy generation. In addition, ground water is also used for free cooling, covering the cooling demands of the active slab system, chilled ceilings and supply air conditioning.
The building consists predominantly of single and double offices arranged along the façade. The auditorium on the ground floor holds 100 people and can be opened and enlarged. A generous atrium connects the ground level with both upper floors. Active slabs systems in the ceiling ensure comfortable work spaces all year round. To reduce noise levels, acoustic absorbers were integrated in the ceiling. However, the function of the ceiling as a thermally activated component with a smooth surface was maintained.
Due to its location, exposed to a railway line and main road, an all-natural ventilation approach using the façade windows would have caused high indoor noise levels. Therefore, a displacement ventilation system introduces fresh air at low velocity into the offices via infloor convectors. The return air transfers from the office to the corridors via air transfer elements integrated in the partition walls and is then exhausted at central locations. The omission of return air ducts saves material and space. Integrated infloor convectors serve as a fast-acting heating system and allow users to control the temperature individually. The air intake for the ventilation system is located at the facade on the ground floor level. After an efficient heat recovery, the exhaust air is used for ventilating the underground parking garage.