Economic evaluation

In order to extend the evaluation from ecological to economical aspects, investments and running costs (cleaning, energy, maintenance etc.) have to be considered as well. The evaluation system offers an EXCEL tool for calculating cost indices according to the morphological box, based on costs of fa? ade components. For purposes of overall judgement the cost indeces can be transformed to marks comparable to the energetical indices.

1.2. Comprehensive evaluation

Finally the separate energetic and economic evalutions can be combined to a comprehensive judgement by the user. For the different aspects of the evaluation relative weights have to be determined by the user. This allows him to stress certain criteria in an individual manner for a certain purpose. A building investor, e. g., will have preferences differing from those of a building owner who intends to occupy the building.

1st International Congress on Heating, Cooling, and Buildings — 7th to 10th October, Lisbon — Portugal /


Fig. 4. Comprehensive evaluation of three fagade systems 3. Additional Applications of Energy Assessmant, Outlook

Currently the eveluation system is an EXCEL tool by which fagade parameters can be classified only stepwise within certain bandwidths. The next target is to develop a tool, which allows a stepless, continuous definition of input parameters. First tests have proved that the output of energetical data can be derived by a five dimensional intepolation tool. There was developed a free choice of interpolation for properties by regession analysis. Thus an unbounded design variety can be evaluated quickly, based on a limited number of elaborate simulations.

The assessment system was initially developed for an application by clients in early design stages. During the process of development there has been discovered a large potential of additional applications. The assessment method might be used by designers and consultants as well in early and advanced design stages for purposes of control and/or optimazation of certain aspects.

The Diploma thesis of Preibler [2] gives an example for the advanced energetical analysis of fagade systems. One objective was to visualize the influence of the five physical design parameters on the energy demand. Three dimensional diagrammes (Fig. 5) and vector-analysis can help to catch the influence on one glance.

Another application of the assessment tool might be to generate facade designs under given boundary conditions. More research is necessary to gain the full potential of energy assessment systems for an improvement of the design process.



Parameter 1

Fig. 5. Total primary energy demand for a given variation of parameters


[1] Gralla, Mike, Muller, Helmut: Unpublished research report for Bundesamt fuer Bauordnung; „Bewertung von Glasfassaden unter Berucksichtigung von Kriterien der Enrgieeinsparung und Wirtshaftlichkeit“, (2008)

[2] Preissler, Andreas: Diploma thesis “Einfluss von Fassadenparametern auf den Gesamtenergiebedarf von Gebauden”, Lehrstuhl Klimagerechte Architektur, TU Dortmund, (07/2008)