EVA - Evaluation of Energy Concepts: Case Study of Siedlungswerk, Stuttgart

This paper presents the evaluation and optimization results of the office building Siedlungswerk as part of the EVA project. Within EVA, 19 German office buildings are being “eva”-luated in terms of energy efficiency and user comfort. Built in the early 1990s in the city center of Stuttgart the building Siedlungswerk provides office spaces for 135 employees on a net heated floor area without a parking garage (NGFr) of 5.589 m2. The evaluation showed an annual consumption of primary energy of 614 kWh/(m2NGFra). This was the highest within the EVA sample and significantly above reference values. Users complained about high temperatures in summer and low temperatures in winter especially during the morning hours. A short term monitoring of the indoor climate confirmed these problems. A comprehensive concept of improvement was implemented at the end of 2004 at a total cost of 250 T€ including 100 T€ for improvements in energy efficiency. The following year showed a reduction of 36 % in consumption of electrical energy and 49 % in gas consumption. The energy savings generate annual cost savings of 50 T€, which equals a return on invest in energy efficiency after two years. The optimized building operation also significantly improved the user comfort.