Main content:
Conversion of a factory building into an office building in Einbeck, Germany
Project participants:
Client: KWS SAAT AG
Architect: Bünemann & Collegen
Energy planner: Büro für Wärmetechnik
Building data:
Building type: Bürogebäude
Location: Grimsehlstrasse 31, 37555 Einbeck
Gross floor area: 6.088 m²
Jury evaluation
"On a complex overall operational site, a mechanical-engineering workshop is being converted into a modern administrative building with impressive architectural and technical standards. 120 office workplaces will be created on 6,200 m² of GFA on four storeys, arranged around a central atrium. Heating and cooling take place using building element temperature control in the newly installed floor slabs, combined with an external biogas CHP plant and use of waste heat from machinery (compressed air generation). Mechanical ventilation with heat recovery completes the indoor environment concept. A former conveyor belt duct will be used as an underground duct. The project sets an example for ambitious conversion of existing commercial buildings to meet changing user requirements."
Project_characterisation
Building concept
At its headquarters in Einbeck, KWS Saat AG plans to convert an existing mechanical-engineering and storage building into an office building for the research and development department. Being the oldest building on the company site (dating from 1946), it has a particular significance in KWS’s history, as it represents the company’s successful new beginning after the Second World War.
The building concept concentrates primarily on limiting the energy requirement and thermal loads by means of suitable construction measures. Alongside the compact and largely division-free design of the building structure, these measures also include: a high thermal insulation standard, the use of thermal mass, a favourable proportion of window openings, and the use of effective sun-protection equipment. The construction measures will put the prerequisites in place to minimise the investment in building systems equipment necessary to cover the energy requirements and loads.
Energy concept
The energy concept foresees the integration of site-specific energy resources into the building’s energy supply. A large fraction of the heating requirement (around 75%) is supplied from the recovery of waste heat from a compressed air generation process with high degrees of utilisation during the winter months. Also part of the supply concept is the connection to the company’s central energy facility with a biogas CHP plant and an absorption cooling system (on the CHP plant).
The ventilation concept, which is limited to the provision of the minimum proportion of outdoor air, also includes the use of resources available on site. Preconditioning of the supply air is carried out in a disused conveyor belt duct: this is an underground duct underneath a storage hall which borders onto the planned building. This duct was originally used to transport seeds via a conveyor belt. The planned use of supply air preconditioning will achieve annual energy savings of around 10%, with only a low additional investment required.
Despite the reduced investment in building systems equipment, the building still achieves good thermal comfort conditions. Simulations have shown that even in critical usage areas a summer room temperature of 26 °C will be exceeded for less than 10% of the annual usage period. The maximum summer temperatures to be expected are around 28 °C.
With a primary energy requirement of 38 kWh/m² p.a., the planned building is 74% below the current legal requirements as per EnEV. The energy supply is CO2-neutral due to the energy requirement largely being supplied by waste heat and renewable resources. As regards sustainability, building components and materials with long service lives and which are as low-maintenance as possible are used. Additional contributions are made by the wood-aluminium composite windows with integrated blinds, which are protected from the weather and simultaneously provide variable sun protection, the necessary glare protection for office workplaces and increased thermal insulation.