Claudia Valverde

Zusammenfassung

Urban surfaces play a central role in mediating microclimatic conditions, influencing not only human thermal comfort but also the viability of urban biodiversity. This study explores porous, geometry-driven design strategies for urban surfaces and evaluates their thermal performance as a preliminary step toward future building envelope systems that accommodate more-than-human inhabitants. With the nest microclimate of cavity-nesting wild bees as the target condition, three experimental setups were conducted using 3D-printed (3DP) porous nesting aids fabricated via Fused Deposition Modeling (FDM) from biobased polymers and compared to a conventional reed-based nesting aid. The samples were installed on a southeast-facing façade in Stuttgart, Germany, and internal nesting tube temperatures were monitored during August 2024. All 3DP samples maintained internal temperatures up to 1.6 K cooler on average than the conventional nesting aid and, critically, none exceeded the 40°C threshold associated with high larval mortality. In contrast, the conventional nesting aid reached peak temperatures of 41.6°C for over eight cumulative hours. While geometric and material variations produced only modest thermal differences among the 3DP configurations, the results demonstrate that porous geometries can reduce extreme heat exposure in sun-exposed urban contexts. These findings support further development of thermally responsive urban surface systems that integrate ecological performance criteria into building design.

Zusammenfassung

Urban surfaces such as Facades and rooftops are critical mediators of microclimatic conditions in cities, influencing the thermal comfort of both human and non-human inhabitants. Within a more-than-human design perspective, these surfaces may be understood as interfaces where microclimatic regulation can support ecologically relevant funtions, including nesting habitats that moderate microclimatic extremes for wild bee species in dense urban environments. This study builds on prior research into additive-manufactured (3D-printed) porous cellular geometries—specifically Triply Periodic Minimal Surfaces (TPMS) and Adaptive Density Minimal Surfaces (ADMS)—developed as structural envelopes for nesting tubes intended to mitigate heat peaks experienced by cavity-nesting wild bees under urban heat island (UHI) conditions. These species experience metabolic stress when internal cavity temperatures (Tnest) exceed 35 °C and face lethal risks above 40 °C. Previous experiments showed that such geometries can attenuate internal temperature fluctuations by up to 1.6 K compared with conventional materials, although passive geometric performance alone proved insufficient during extreme summer conditions. To enhance thermal regulation, a bio-inspired evaporative-cooling strategy was developed, modelled after the droplet collection and retention behaviour of Apis mellifera. Here, the honeybee is used solely as a biological analogue for water-management mechanisms, rather than as the species under investigation. Comparative field tests in Stuttgart, Germany, evaluated small-scale water-supplied (sWS) and control (sC) samples alongside traditional nesting materials. There resultsinformed the design of full-scale Facade panels—a water-supplied (pWS) and a control (pC) variant—later tested in a climatic chamber simulating heatwave conditions. Across experiments, pWS achieved mean temperature differentials (ΔT) of 8.6–10.2 K relative to pC, indicating the technical potential of evaporative cooling to reduce microclimate thermal stress in biologically sensitive cavities and to inform climate-responsive architectural surface design.

Zusammenfassung

Urban surfaces, far from being static architectural elements, actively mediate ecological and climatic processes in urban environments (Meggers, 2015; Barry and Blanken, 2016; Yang et al., 2023). This study is part of an ongoing Ph.D. project at the Cluster of Excellence Integrative Computational Design and Construction for Architecture (IntCDC), University of Stuttgart, investigating geometry-driven thermal regulation in bio-integrated urban surfaces. It contributes to a broader exploration of additive manufacturing and porous structures for enhancing urban biodiversity, particularly for wild bee conservation. Using wild bee nesting as a focal case study, it addresses the regulation of temperature within nests to mitigate the detrimental effects of elevated temperatures, including developmental delays, metabolic stress, and offspring mortality (Radmacher and Strohm, 2010; Hamblin et al., 2017; Maebe et al., 2021; Vilchez-Russell and Rafferty, 2024). As primary pollinators, wild bees are indispensable to biodiversity and urban ecosystem functioning (Lowenstein et al., 2015; Winfree et al., 2011). They enhance green infrastructure by supporting plant reproductive success, contributing to urban resilience and ecological balance (Kammerer et al., 2021; Ferrari and Polidori, 2022). Urban surfaces present a valuable opportunity to create continuous networks of nesting and foraging resources, promoting ecological connectivity within the built environment (Radfar, 2012; Cruz, 2016; Bornschlegl et al., 2023; Prieto and Pastén, 2024). By serving as permeable interfaces, these surfaces can facilitate species movement, provide access to various resources, and help maintain the genetic diversity necessary for adapting to environmental changes, such as climate change (Everaars et al., 2011; Scheffers et al., 2016; Zölch et al., 2016). Given the limited dispersal abilities of solitary bees, a continuous network of resources in urban areas can play an important role in their conservation (MacIvor and Packer, 2015; Ostap-Chec et al., 2021, Polidori et al., 2023). This study explores geometry-driven strategies to address microclimatic challenges, employing porous cellular structures for their thermodynamic properties and potential to support various species, from pollinators to microfauna. Additive manufacturing was chosen to fabricate these complex, adaptive geometries. 3D-printed samples were tested alongside one traditional nesting aid on a southeast-facing facade in Stuttgart, Germany, in August 2024 (see Figure 1). While the 3D-printed designs demonstrated moderate thermal benefits, their value lies in reimagining urban surfaces as components for fostering ecological resilience. Innovation and speculative approaches are central for addressing contemporary ecological challenges, which are increasingly defined by legal frameworks and policy directives (Federal Ministry for the Environment, 2010; Federal Parliament of Germany, 2020). This work examines the role of the more-than-human approach in the built environment. It presents urban surfaces as potential adaptive and multifunctional systems that could actively promote biodiversity and ecological connectivity. This perspective sets the stage for future improvements in the experiments.

Zusammenfassung

In the context of pandemic restrictions and the need for climate change adaptation, our academic exercise ventured into Biodesign by engaging honeybees in a co-design framework. Conducted in Pichincha, Ecuador, from October 15, 2021, to January 15, 2022, and November 16, 2022, to February 28, 2023, this exercise explored the co-design potential between humans, non-human entities, and machines. Using Rhino Grasshopper, we created an evolutionary algorithm to shape wax films for bee-integrated 3D printing. The iterative process depended on ecological timelines and environmental conditions, evolving with bees' natural behavior and climate factors. This approach emphasizes non-human-centric design, highlighting the roles of temperature, humidity, and flowering plant availability. While not for immediate application, this exercise speculates on future design with non-human entities, showcasing the synergy of digital, human, and biological inputs and promoting post-anthropocentric design practices.