GEMA – Assessment of the performance of energy-efficient demonstration buildings

Starting point/Motivation

In Austria, in recent years, numerous innovative, energy-efficient buildings have been built and existing buildings renovated. Low-energy and passive houses have to face stiff requirements: a significant reduction in the use of energy and materials, the increased use of renewable energy sources, in particular solar and geothermal energy, the use of ecological building materials, an increase in room comfort and all this with comparable cost to conventional construction. In order to ensure that the planned energy performance and claimed level of sustainability are actually achieved, the real energy consumption compared with the energy demand calculated in advance of numerous buildings has been assessed within the funding program "Stadt der Zukunft".

Contents and Objectives

The objective of this report is to present to the public additional innovative energy-efficient buildings in Austria and to make the potential of innovative building concepts and technologies visible. The selected buildings focus on service buildings, the monitoring and assessment results shall serve future building projects to realize the optimization potential with regard to energetic, ecological and social aspects. The buildings investigated are: the office buildings IZM Illwerke (Vorarlberg), Ecoport Saubermacher (Styria) and Fröschl Haus (Tyrol), the laboratory building WEIZIV (Styria), a supermarket of MPREIS (Tyrol), the Hotel Mondschein (Vorarlberg), the nursing home Steinfeld (Carinthia), the culture and event center Hallwang (Salzburg) and the students dormitory PopUp Dorms (Vienna).

Methods

In all buildings, the energy flows for the supply and distribution of heating, hot water and cooling energy, the object-related electricity consumption and, if available, power generation with PV systems were recorded during a period of at least twelve months. The collection of the measured data mostly at fifteen-minute intervals and data validation was carried out using a professional web-based hardware and software solution. The primary objective was the evaluation of the measured data based on energy indicators and existing guidelines. The room parameters temperature and relative humidity, and in some cases the CO2 content in at least three rooms, were also recorded mostly at fifteen-minute intervals. The use behavior was described based on the users of the building as well as on the operation and parametrization of the buildings energy facilities. All buildings were classified in a sustainability assessment according to the Total Quality Building (TQB-) system, including technical, ecological, economic and social criteria.

Results

For most of the nine service buildings presented, the evaluation of the measured data shows that the measured end-energy consumption corresponds well to the planned values calculated in advance. Naturally, deviations occur when the type of use or the buildings energy supply concept deviate significantly from the planning in reality. In most buildings energy efficiency potentials could be identified in the operation of the buildings energy facilities. For the first time, the building operators were given a comprehensive insight into the operation of the facilities, especially in buildings with complex energy supply and distribution systems, which led to retrofitting measures in two buildings during the project period. The classification of buildings according to the TQB system resulted for all buildings in the range of more than 80% of the maximum score, which also confirms the high quality and sustainable orientation of all presented buildings. The recommendations to future building designers and operators relate primarily to the operation of the building energy facilities and to challenges of energy monitoring itself.