Edith A. Gonzalez

Abstract

Angesichts des steigenden Energiebedarfs im Gebäudebetrieb gewinnt die Entwicklung adaptiver Fassadensysteme zunehmend an Bedeutung. Insbesondere solaraktive Gebäudehüllen bieten Potenzial, durch gezielte Steuerung von Sonneneinstrahlung, Belüftung und Tageslichtnutzung den Energieverbrauch zu senken und gleichzeitig den Nutzerkomfort zu erhöhen. Das Forschungsprojekt FlectoLine-Fassade verfolgt das Ziel, intelligente, materialbasierte adaptive Fassadenlösungen ohne klassische Antriebs- und Steuerungssysteme zu realisieren. Im Zentrum stehen dabei flexible Faltelemente, die auf bioinspirierten, nachgiebigen Mechanismen basieren und sich durch die elastische Verformbarkeit von FVK-Platten ohne Gelenke auszeichnen. Durch integrierte pneumatische Aktuatoren, präzise programmierte Materialsysteme und gezielte Differenzierung der Steifigkeiten kann eine kontrollierte Faltbewegung bis 90° erreicht werden. Neben einem Hybridmaterialsystem wurde eine thermoplastische Variante entwickelt, die einfacher zu fertigen und recycelbar ist. Umfangreiche Belastungstests belegen die Langlebigkeit beider Systeme. Ergänzend wurden flexible Photovoltaikzellen integriert, um Energie zu gewinnen. Ein digitaler Zwilling mit Sensorik und Wetterdaten steuert die Fassade in Echtzeit. Der Demonstrator mit 101 individuell verformbaren Elementen auf 83,5 m2 zeigt die technische Umsetzbarkeit und das energetische Potenzial adaptiver Fassadentechnologien der nächsten Generation.

Abstract

Adaptive facades can greatly impact a building’s energy balance by responding to external climates and by regulating internal conditions. With the integration of solar energy harvesting components, they have the potential not only to reduce the energy loss of buildings but also to gain energy. This premise has been tested within the framework of bio-inspired compliant mechanisms for adaptive façade elements, developed at the University of Stuttgart. Due to the flexible kinematic behavior of bio-inspired adaptive architectural elements, an innovative and simple alternative to common, more complex applications of adaptive façade components is obtained. The research presented aims at establishing the environmental criteria that will lead to an improved energy performance of a building using elastically deformable, adaptive faҫade elements with integrated photovoltaics. Through simulations and physical testing, the influence of daylight, solar radiation, and the building´s thermal balance are evaluated. The findings of this research are showcased on an adaptive façade consisting of pneumatically actuated, glass fiber-reinforced plastic laminates with integrated photovoltaics, assembled at Botanical Garden in Freiburg, Germany. Relying on environmental sensing, this façade is able to adapt over time in response to solar conditions with the goal of finding the right balance between low-energy building operation, high indoor environmental quality, and high energy harvesting. This study provides a novel, integrative design method utilizing adaptive building envelopes that successfully react to varying environmental conditions in an energy-efficient and cost-effective manner.

Abstract

This paper aims to define the influencing design criteria for compliant folding mechanisms with pneumatically actuated hinges consisting of fiber-reinforced plastic (FRP). Through simulation and physical testing, the influence of stiffness, hinge width as well as variation of the stiffness, in the flaps without changing the stiffness in the hinge zone, was evaluated. Within a finite element model software, a workflow was developed for simulations, in order to infer mathematical models for the prediction of mechanical properties and the deformation behavior as a function of the aforementioned parameters. In conclusion, the bending angle increases with decreasing material stiffness and with increasing hinge width, while it is not affected by the flap stiffness itself. The defined workflow builds a basis for the development of a predictive model for the deformation behavior of FRPs.