Bachelor's thesis Simon Kreischer


Assessement of the Efficiency Approach and the Renewable Energy Approach for the Renovation of Existing Buildings Based on Technical, Environmental and Economic Criteria

Renovation Copyright: EBC

​In order to reach Germany’s climate protection goals by the year 2050, a renovation of the current building stock is inevitable. The current energetic renovation rate is insufficient to achieve the desired goals. Multiple studies indicate that existing uncertainties and lack of information on the part of homeowners counteract an increased renovation dynamic. The group of homeowners is attributed with a pronounced heterogeneity, which results in different requirements for an energetic renovation. In order to take account of the heterogeneity of the homeowners, an interdisciplinary evaluation of different renovation approaches is required.
The present bachelor thesis deals with an examination of two different renovation approaches. The first approach ("efficiency approach") involves an increase of the building efficiency, in particular the heat-transferring enclosing surface and the heating technology. The second approach ("renewable energy approach") focuses on the integration of renewable energy systems into existing buildings. The main focus is on how the efficiency approach and the renewable energy approach for the renovation of existing buildings should be evaluated, taking into account technical, ecological and economic criteria. The procedure for answering this question is divided into three steps. In the first step, the theoretical foundations of various evaluation criteria are presented. The primary energy demand is used as a technical evaluation criterion. The ecological evaluation criteria are CO2-emissions and – based on the "Application of the Assessment System for Sustainable Building” – four further emissions-related environmental impacts during the use phase. Based on the VDI guideline 2067, the annuity, the resulting annuity gain and the dynamic amortization period are used as economic evaluation criteria. In the second step, these evaluation criteria are applied to a representative sample building and various renovation packages. Selected results are highlighted. The third step involves the discussion of the results presented with reference to the theoretical foundations and the formulated question.
Based on the calculations, it can be shown, that the renewable energy approach has advantages over the efficiency approach. In particular, it is the superior approach with regards to the technical evaluation criterion and CO2-emissions. In contrast, the implementation of the efficiency approach proves to be the better alternative with regards to the four other emission-related environmental impacts in the use phase and economic criteria.