To the relation of urban building types and energy
Since the beginning, the usage of solar energy has significantly influenced the form of urban structure and architecture. First examples of this go as far back as to Ancient Greece. The Megaron an archetype of solar architecture became a guiding principle of ancient urban planning. The city of Priene is one of the examples of an urban structure that profited from maximal solar energy through passive measures. The attempt to integrate the use of solar energy into architecture and city planning has been continued into modern times through planning principles like the British Presciption Act in 1832 or the American Zoning Law in 1916 but also through designs from Architects and Planners of the „International Style“. In the 1920’s, radical counter concepts of horizontal densified European cities were composed of predominantly directed and solitary urban structures. Several of the designs of this time period work with East-West-oriented strip-like structures (e.g. Ludwig Hilberseimer: development project Friedrichstadt, Berlin, 1928; Macel Lods: reconstruction plan Wallstrasse, Mainz, 1947) The origins of energy-efficient architeture since the mid 1980s, however, turn the previously preferred East-West-Orientation by 90 degree and promote North-South line-like buildings. This row is based on the extrapolation of energy calculation methods used for thermal heat. The Passive House and now even the Surplus House, developed in the new millennium, make the North-South orientation a dogma of solar building. The latter mainly uses exposed 30 degrees South tilted roofs to produce electricity via active systems (e.g. Photovoltaic). Accounting methods developed to calculate heat requirements are also used to determine electricity demands and potentials from active solar systems. Buildings that produce more electricity throughout the year than they require were designed with the goal to maximize yield (here also titled as „Energy“ paradigm). The public electricity grid hereby serves as an unlimited storage system. However, this method doesn‘t sufficiently take the volatile character of regenerative solar energy into account. An hourly load analysis shows that the current yield varies significantly due to changing solar wave angles or changing weather situations. In addition, the demand itself changes throughout and hour, day and week. Therefore, it appears necessary to move from maximizing the yield (paradigm ‘energy’) to maximizing self-sufficiency (paradigm ‘load’). Consequently, this paper develops the hypothesis that this new paradigm leads to a re-evaluation of which structures (e.g. North-South, East-West, aligned/not aligned, etc.) are considered most load efficient in the future. In this context, this research questions if the until now preferred North-South, 30 degree tilted solar active roof top systems are still the preferred model. Additionally, the paper evaluates how different usages require different forms to be most load efficient. Finally, the work examines how useful active systems in facades or free space elements (e.g. carports, garages, canopies) are and in which ways these systems can contribute to a higher performance of urban spaces. In order to answer these research questions, a typification of urban structures is made and performance-specific day tapes are developed. These take hourly changes in terms of the side of the demand, the overall electricity demand, the side of the supplier and the current deployment potential into account. A custom programmed energy model analyzes systematically the load of different abstracted primitives (test bodies) as well as of all common urban structures (buildings types). The paper uses curve sketching to provide a qualitative and quantitative evaluation of different scenarios from an energy (energy coverage) and a load (self-sufficiency percentage) perspective. Goal of the research is to promote a new understanding of solar building under the premises of the present and anticipated technological developments in the field of active systems.
Prof. Dr.-Ing Siems, Tanja [Reviewer]
Prof. Hegger, Manfred [Reviewer]