Using buildings as energy storage - Monitoring project: Detached house H and detached house F Energy source wind power – Energy source solar power

Starting point / motivation

In the past, thermal building component activation (TBA) has already been applied frequently within office and administration buildings, schools and hospitals and partly in commercial buildings, and there almost exclusively in combination with further heating and cooling systems to compensate for peak loads. In Austria, dozens of thermally activated detached houses on differing technological standards have been constructed over the last years. Nonetheless, TBA in housing has not yet reached a wider public. Particularly in the Western Austrian provinces, several buildings were constructed with TBA in combination with solar thermal supplies. This solution was applicable only to a limited extent to the urban, less sunny but more windy East of Austria.

Contents and goals

Constructing two detached houses with TBA in the East of Austria, supplied by different renewable systems, was the aim of this project: The heat pump of house H is operated by wind electricity, house F operates on solar energy. The aim was to demonstrate how the combination of heat pump, geothermal energy and renewable energy, i.e. solar heat and wind electricity, could be used to increase the share of renewable energy for space heating. For the house supplied with wind electricity, an additional and essential aim was making use of excess wind electricity and possibly reducing the grid loads via the use of the TBA construction. With the implementation of this combination of thermal building activation and supply by wind electricity in an exemplary detached house the technology should be made applicable for multi-storey housing in the densely populated urban environments.

Methods

One of the main contents of the monitoring project was the comparison of the measured data with the projected demands for both energy supply systems (wind and solar), broken down into heating and hot water supply. Furthermore, the buildings have been tested and compared in their functionality and their temperature behaviour, their share and availability of renewable energy as well as their temporal distribution.

Collecting and transmitting of the data of both buildings to project engineer was electronically via the internet. Experiences with self-regulating facility controls were collected and analysed. After the completion of the measurement, a comparative analysis was made; in addition, the Austrian Ökologie-Institut performed an independent survey of user satisfaction with personal interviews.

Results and conclusions

Particularly for house H and the supply with wind energy, the monitoring project showed that TBA creates the preconditions for effective energy flexibility. In the bi-annual monitoring, 80 % of the electricity used for heating via heat pump in house H came from excess wind electricity. Thus, buildings can contribute directly to the decentralised stabilisation of the energy grids, for electricity grids as well as for heat grids. With the appropriate provisions, thermal building activation facilitates shifting energy demand in time and limiting the heat supply to those periods, in which renewable electricity is in excess and available at lower costs.

Prospects

The climate targets of the Austrian federal government envisage a shift in the total electricity supply to 100 % renewable energy until 2030. Fully exploiting the potential of thermal building activation as energy storage is decisive for this aim, since concrete is a relatively low-cost, easy to recycle and, in addition, inert storage. The energy flexibility of thermally activated buildings allows for a load control at demand level, tailored to building's energy demand and/or the requirements of the surrounding grids. Given the increasingly hotter summers, thermal building activation also provides for an option for passive cooling of buildings at low energy and resource demand. 2019 two housing complexes using thermal building activation in combination with wind energy for heating and cooling will be completed. The association of the Austrian cement industry contributed to the realization of these projects and supervises the thematic area thermal building activation within the framework of Mission Innovation Austria.

Project management

Baurat h.c. Dipl.-Ing. Felix Friembichler - Vereinigung der Österreichischen Zementindustrie

Project or cooperation partners

• FIN – Kuster Energielösungen GmbH.
• GRT Gebäude- und Regeltechnik GmbH.
• WEB Windenergie AG
• Zement + Beton Handels- und Werbeges. m. b. H.
• Österreichisches Ökologie-Institut

Zement + Beton Handels- und Werbeges. m. b. H.
Reisnerstrasse 53
A-1030 Wien
Tel.: + 43 (1) 714 66 81
E-Mail: Friembichler@zement.at
Web: www.zement.at