Monitoring Sunhouse Eferding
Starting point / motivation
Austria has committed itself to raise the share of renewable energies at final energy consumption to a ratio of 34 % until 2020. The increase of energy efficiency and reduction of greenhouse gas emissions are important aims of European environmental politics. Beside the use of other renewable energies, only a forced extension of solar energy use can contribute to this aims. An annual growth rate of the installed collector area of 20 % is required to achieve a share of solar heat of 10 % until 2020. Solar energy is a CO2 free primary energy source which is available nearly indefinitely hence deserves particular attention in a long-term energy strategy.
Contents and goals
With the sun house concept, there exists a power saving construction type with an extremely low primary energy demand and very low greenhouse gas emissions. The Sunhouse Eferding should stimulate the awareness of the sun house concept in Austria and is used as an event and exhibition building. It has projected CO2 emissions of 0.29 kg/m2a and a primary energy balance of zero regarding the heating energy consumption in a combined cycle with a neighbouring factory. In Austria, high solar fractions of 50 % to 100 % are not yet standard. Though large-scale solar installations and solar combination systems are strongly promoted in Austria recently, however, in handling these technologies a set of problems still exists: It is quite difficult to set complex energy systems to run in a proper operating state. The Sunhouse Eferding disposes two different storage systems: a cylindric steel buffer storage inside the building and two underground ball tanks outside the building. During the monitoring of Sunhouse Eferding the functionality of this model project was examined and the recorded solar energy gains were analysed. Moreover, complex operating situations of the energy-technical appliance were tested.
Methods of treatment
By means of numerous measuring devices, data were collected in short time intervals at different positions in the energy-technical system of the Sunhouse Eferding. The data were stored digitally and processed in regular time intervals into diagrams. In management discussions the results of the measurement were monthly analysed, malfunctions were localised and measures were set to improve the operation of the energy-technical system. The effectiveness of these measures was checked in the subsequent discussions and, if necessary, the settings were further improved. The energy balance of the object was evaluated constantly.
Expected results / conclusions
In the first operation phase of the Sunhouse Eferding the projected solar gains of the simulation were not reached. More than once false settings in the control system and other problems could be localised. Moreover, more heating energy was necessary for drying out the building materials during the first year. The fact that the energy balance of the second operational year was much better than of the first year proves the effectiveness of the adaptation measures during the monitoring process. More energy could be delivered to the factory than was needed from there for additional heating.
This example shows the great importance of system control and monitoring − even for smaller installations − for the first two or three operation periods. Only if efficiency aims are achieved by each single installation, political efficiency programmes can be effective in sum.