Thomas Bednar

Transformation of Fundamental Parameters for Energy Demand and Indoor Temperature from Room Level to Building Level

Because the thermal optimization of a new building must be done in the planning phase, possible thermal optimizations are sought for the building by varying several parameters. This research article is based on the research of ‘climate surfaces’ by Prof. Keller and Dr Burmeister at the Federal Institute of Technology in Zurich (Burmeister and Keller, 1998). The question should be resolved whether this simplified method using climate surfaces is applicable to the entire building. The most important parameters of the building have been systematically changed and their impact on energy performance during different outdoor climate changes was observed. As a result, the impacts on the following are presented and discussed: Heat energy demands, Cooling energy demands, and Summer indoor temperatures. The results of these investigations showed that the ‘multizone climate surface’ method is a very practical and clear strategy for estimating the thermal behavior of a building by the correct selection of three determining parameters. Already in an early planning stage, it is possible to establish the optimal building data, at a sufficient level of detail, where energy consumption has been concerned. The study is carried out using the monthly energy balance method and dynamic simulation using ‘BuildOpt’ software. The objective was to establish if the much simpler monthly balance method will give sufficiently precise results for this optimization, or if a simulation must be performed. The results of the analysis indicate that the monthly balance method is inaccurate, especially for buildings with low energy demands. Subsequent studies deal with the optimization of the most important construction assembly parameters of a building for specific climates. The results of the optimization studies are presented in this article.

Sound radiation efficiency of lightweight building constructions—Study on the influence of panel fastening by numerical calculations and laser scanning vibrometry measurements

The aim of the presented work is to develop a calculation model for predicting vibration characteristics and consequent measures of the sound radiation efficiency of lightweight building structures including the influences of their connection means. An application of the currently normative covered processes for these structures is excluded in the relevant body of standards. Through the analysis of the velocity distribution on the surface by laser vibrometry and the simultaneously measurement of the introduced vibration energy, transfer functions could be identified. Within the scope of this work, different influencing parameters for the formation of the connecting joint between wall components are identified and their effects on the vibration characteristics are quantified. The measurement results offered not only the identification of parameters but can also be used in the development and validation of the simulation model based on the finite element method. A good correspondence between measurements an...

Ausweis über die Gesamtenergieeffizienz

Nachdem in den bisherigen Kapiteln die Grundlagen zur Berechnung von Energiekennzahlen dargestellt wurden, soll das gegenstandliche Kapitel — gleichsam als Hohepunkt — Umfang, Inhalt und Aussehen des Energieausweises wiedergeben. Betrachtet man dazu die letzten Monate vor der Fertigstellung der OIB-Richtlinie 6:2011 [66] — zum Zeitpunkt der Fertigstellung dieses Buches war der Diskussionsprozess noch in vollem Gange —, darf festgehalten werden, dass offensichtlich fur die Bauwirtschaft, aber durchaus auch fur die Energiewirtschaft infolge der Angabe fur Primarenergiebedarf und Kohlendioxidemissionen, insbesondere das Aussehen des Energieausweises von besonderer Bedeutung ist. Dabei wird mit Aussehen im engeren Sinne das Labeling auf der ersten Seite des Energieausweises gemeint. War dies bisher ausschlieslich dem Heizwarmebedarf vorbehalten, so konnte im Zuge des Entwicklungsprozesses vermittelt werden, dass dies wohl nicht unbedingt die Grose ist, mit der die Gesamtenergieeffizienz eines Gebaudes zum Ausdruck gebracht wird. Leider definiert die EPBD:2011 [50] den Begriff Gesamtenergieeffizienz mit einer Energiemenge, die notwendig ist, um ein Gebaude an einem bestimmten Standort mit einer bestimmten Nutzung betreiben zu konnen. Dies entspricht im Wesentlichen dem Endenergiebedarf oder vielmehr — zukunftige Entwicklungen vorwegnehmend — dem Lieferenergiebedarf.

Enhancement of impact sound insulation for “Gründerzeit‐Häuser” build around 1900 during refurbishment using concrete‐wood composite floors or suspended ceilings

During refurbishment of Viennese buidlings that have been erected around 1900 an important aspect is to enhance the impact sound insulation of the old wooden floors. Usually the floors are wood beam floors and the uppermost floor is a massive wooden floor called Dippelbaumdecke. Two important measures are taken to increase the impact sound insulation to achieve the minimum requirement of LnTw<=48dB. The paper describes the design of an optimal suspended ceiling to avoid additional measures and as an alternative the impact of an additional thin concrete floor on top of the Dippelbaum-floor to achive minimum floor heights. As the thin concrete floor has a much larger area than the rooms below the measured results showed a big influence of concrete floor area on the impact sound level.