The increasing densification of urban areas exacerbates challenges such as global warming, air pollution, and biodiversity loss. Facade greening offers a sustainable solution by transforming monotonous building surfaces into vibrant, climate-active zones. These green facades improve the microclimate through cooling, shading, and air purification, while promoting biodiversity and enhancing energy efficiency. This study employs novel large-diameter rolling bearings for movable greening systems, enabling adaptive botanical processes and facilitating ergonomic maintenance. The result is innovative, sustainable facades that deliver ecological, social, and aesthetic benefits, contributing to climate adaptation and improving urban quality of life.

Motivation

The increasing densification and sealing of urban areas, as exemplified by the Campus Lichtwiese of TU Darmstadt (see Figure [1] left), presents major challenges for cities regarding quality of stay, microclimate, and biodiversity. Particularly in areas with many multi-story buildings and flat facades made, for example, of concrete or glass, natural greenery is often lacking, which is essential for cooling, air purification, and habitat. Facade greening offers an effective solution here: it enables botanical processes and transforms monotonous building envelopes into vibrant, climate-active surfaces that protect against overheating in summer, bind fine dust, and promote biodiversity (see Figure [1] right).

Approach

The present study focuses on the application of novel, resource-efficiently manufactured large-diameter rolling bearings (see figure [2]) for movable facade greening systems in existing and new buildings. The aim is to enable adaptive botanical processes that optimize plant-specific supply of sunlight, nutrients, and (rain)water. The mobility of plants allows for ergonomic maintenance activities such as planting, sowing, harvesting, and mulching of the movable beds. This enhances natural cooling effects, enables targeted shading control, and improves the energy efficiency of buildings. Botanical knowledge underpins the development of process engineering optimizations through control and regulation of the movement paths of the beds via irrigation, supply, and shading zones. The movable greening systems also create new architectural possibilities to integrate sustainable and attractive green spaces on complex or large-scale facades. The project combines three scientific disciplines: research on plant growth and urban gardening conditions, design of architecturally and functionally optimized planting containers by additive manufacturing, and the development of sustainable, cost-effective lightweight large-diameter rolling bearings. The consortium benefits from complementary expertise focused on these objectives. Novel technologies allow production of large bearing rings from high-strength sheets, enabling a functional prototype that demonstrates feasibility and effective facade mounting. Computer-aided architectural design simulates time-resolved daylight, evaporative cooling, and shading patterns throughout the year, providing the basis for promoting botanical processes that positively impact air purification, temperature regulation, solar radiation absorption, and rainwater utilization. Digital fabrication data sets for planting containers and fixation technologies are also generated.

Acknowledgements

The research presented here was conducted within the framework of an interdisciplinary project generously supported by the Fritz and Margot Faudi Foundation. We would like to express our sincere gratitude to the Foundation for their financial support and the trust placed in our work. Furthermore, we extend our thanks to all project partners involved for their valuable collaboration and constructive contributions, which have been integral to the success of this project.

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