Biomimicry in Temporary Architecture: Biomimetic Concepts for Responsive Skins

BIOMIMICRY IN TEMPORARY ARCHITECTURE

BIOMIMETIC CONCEPTS FOR RESPONSIVE SKINS Stephanie Bashir

1

ABOUT/ This publication compiles a selection of architecture student projects developed at Phoenicia University as part of ARCH 300/ Design Studio III taught in Fall 2019/2020.

Design Studio III is the first of eight architectural Design Studio courses, systematically and sequentially expanding upon the theoretical, critical, empirical and technical skills and information acquired in the two foundation level studios at the College of Architecture and Design. DSIII is a research based, process oriented studio. For its third edition, the studio introduced students to Biomimicry and the principles of Biomimetic design in the context of environmentally responsive architecture. Students stepped into the study of Biology for inspiration in answering some of the environmental challenges faced in Architecture. The purpose is to train a new breed of interdisciplinary designers to analyse and emulate integrated design solutions as well as to harness a kind of design sensitivity that caters for a responsible contribution to the built environment.

Credits Author: Stephanie Bashir College: College of Architecture and Design, Phoenicia University, Lebanon Program: Bachelor of Architecture 2019-2020 Course: ARCH 300 Tutors: Stephanie Bashir (MArch IaaC Bracelona), Jamil Abou-Assaly (MArch ALBA/ University of Chaillot, Paris), Zahraa Makki (MArch SED, AA London) Students Karim Hamieh, Ahmad Fakih, Alaa Sabra, Ali Matar , Ali Hmede, Ali Shehab, Ali Al Amine, Ali Mzannar, Ali Olaek, Ali Bzeih, Ali Youssef, Almaza Aoun, Fatima Hachem, Fatimah Zangi, Ghadeer Youness, Hala Mansour, Hanan Fakih, Hassan Kobeissi, Hussein Arnaout, Ibrahim Issawi, Inaam NaserAldin, Jana Chmaissani, Jana Fakih, Layla Ghaddar, Mahdi Hijazi, Mariam Eidi, Maya Fakih, Mohammad Akkoush , Moustafa Saleh, Nour Sbeiti, Nourhan Kattin, Rawan Azzam, Remi Hattab, Rima Fakih, Saleh Dirani, Sara Hamieh, Sara Shaaban, Yara Harkous, Yara Fakih, Zainab Shami, Zeinab

Stephanie Bashir is a multidisciplinary architect, computational designer and educator based in Beirut. She earned her BArch from the American University of Beirut (AUB) and pursued graduate studies at the Institute for Advanced Architecture of Catalunya (IaaC) in Barcelona, specializing in Parametric Design and Digital Fabrication.

Stephanie’s professional experience includes working on medium to large scale architecture and urban design projects. She received professional training at KPF London and Bernard Khoury Architects prior to joining Atelier des Architectes Associés where she oversaw projects from concept to completion (‘09-’13). Since her return to Lebanon in 2014 she has been actively pushing for the proliferation of new technologies in the local design industry and education, leading and cotutoring IaaC’s Global Summer School program in Beirut (‘16-’18) and participating in Beirut Makers collective. Stephanie is currently an assistant lecturer at LAU and a member of the co-founding team of academics at the College of Architecture and Design at Phoenicia University, South Lebanon.

Copyright ©2020 Stephanie Bashir All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any information storage and retrieval system, without permission in writing from the copyright owners.

CONTENTS

Introduction

2

Studio Methodology

4

Projects 1/ PASSIVE SOLAR SHADING USING SHAPE MEMORY ALLOY

6

2/ WATER HARVESTING TENSILE STRUCTURE

12

3/ AERODYNAMIC BENDING-ACTIVE STRUCTURE

18

4/ REPTILE SKIN-INSPIRED PAVILION

24

5/ FOG AND MOISTURE COLLECTING BAMBOO STRUCTURE

30

6/ AIR PURIFYING PAVILION

36

7/ HEAT ABSORPTION THROUGH RADIATION

42

References

48

1

INTRODUCTION

_ The amount of primary energy consumed by buildings and the resulting volume of CO2 emission are posing serious threats to the environment and aggravating the impacts of climate change. In effect, energy conservation has become one of the key aspects of sustainable design, a now widely adopted design strategy.

Environmentally conscious practices and designers are increasingly employing advanced design tools early in the design process in order to inform design decisions and optimize building energy performance based on feedback loops.

This growing awareness regarding building performance coupled with the availability of advanced software enables novel design approaches with complex outcomes of which is Biomimicry, an innovative design approach that uses nature as reference to propose smart solutions to human problems. This analogy is based on the many parallels shared by the two disciplines (Architecture and Biology), particularly for what relates to the relationship between form and function (morphology), between part and whole, and relationship to surrounding environment. It is well established that nature has evolved through billions of years and developed sophisticated and numerous means to adapt to its environment and survive adverse climatic conditions suggesting that certain laws and principles in nature may be studied through Biology and applied in Architecture.

It is worth noting that the application of lessons found in nature transcends the mere copying of form and delves deep into the underlying principles that govern physiological and behavioural evolutions and adaptations necessary for the well-being and survival of an organism within its respective climatic environment.

ABOVE Bio-inspiration: Cuttlefish skin layers BELOW Cuttlefish displaying electric skin

2

Among the subcategories of Biomimicry is the study of Skins. In biology, skin is the largest organ that contains and protects all other body organs; it provides sensation and regulates water and heat to ensure the comfort and wellbeing of the respective organism. In architecture, skin represents the boundary separating interior and exterior space.

Similar to natural skin, it acts as the interface, the envelope through which a building interacts with the environment through layers reacting to light, heat, air, moisture, and sound in order to maintain optimal internal conditions.

Exploring nature’s strategies in thermoregulation and water management, and applying them in architecture gives rise to a new type of performative structures capable of responding to various dynamic environmental conditions while potentially reducing the heavy impact of energy consuming systems on the environment: That has been the focus of our studio.

Stephanie Bashir, Lecturer, Phoenicia University ABOVE LEFT Photochromic facade* (non-active) ABOVE RIGHT Photochromic facade* (active) BELOW Different design options based on location* *taken from Chromatic Skins by Stephanie Bashir, Carlos Bausa Martinez, Hristo Kovachev

3

STUDIO METHODOLOGY

_ The studio adopted a solution-based approach (Biology to Design) or a bottom-up approach, meaning that the design process was informed by the scientific knowledge of biologists rather than centred around a specific human design problem.

We started by having a general overview of some of the adaptive properties displayed by living organisms through their skin systems and bahavior within specific climatic environments. Students studied the physical properties responsible for the skins’ performance such as surface form, texture, layers, structure, and patterns, and catalogued their findings.

They were then asked to narrow down their search to establish a focused topic, a theme of interest represented by a thesis statement and tackling one environmental parameter such as sun, water, or air.

They were asked to identify 3 “champion” organisms that master adaptation in response to that particular climatic parameter and represent, using sectional drawings and diagrams, the underlying principles that rendered the organisms’ skin a smart/responsive system.

BELOW Students working on models

4

TOP Process models in desk-crits

The students synthesized their findings and conceptualized them to develop a modular skin system. First, they developed a 3-dimensional interpretation of the natural skin in the form of an architectural component. They explored the tectonic qualities of their design by building a real scale prototype identifying its variable parameters.

Based on their respective systems, students were given the freedom to choose an appropriate site for a small scale pavilion structure onto which the skin would be applied. Following a thorough analysis of the climatic, physical and visual characteristics of the site’s environment, the students developed, using low-tech and analogue form finding methods, physical models that allowed the performative aspect of their designs to be experienced, tested, and optimized.

The projects realized by year 2 students depart from the analysis of scientific information made accessible through a number of reliable sources. The projects are by no means final products but rather concepts showcasing some of the possibilities of biomimetic or bio-inspired design. Given the level of the course we focused on parametric logics rather than the use of software and stressed a hands-on approach that relied on model making to prototype components.

The original content of the book has been entirely revised and developed by the author.

5

6

1/ PASSIVE SOLAR SHADING USING SHAPE MEMORY ALLOY Student: Sara Chaaban Proposed location: Parc de la Ciutadella, Barcelona

A responsive installation provides passive shading on the lake bridge of Cuitadella park in Barcelona. The structure draws biomimetic principles from the dragonfly, applying a number of temperature-regulating techniques.

Research shows that a dragonfly uses basking to tilt its wings towards the sun directing solar radiation towards its body. At other times, it uses rapid wing movement to increase body temperature. To avoid overheating, it takes the obelisk position, minimizing wing exposure to sun. Another interesting feature is varying its wing color patterns depending on temperature. This project suggests that thermoregulation is primarily achieved by changing the angular position of wing surfaces with respect to the sun. The skin system interprets the dragonfly’s geometric tessellation, wing coloration and corrugated surfaces through a folded lineage of pentagonal modules offset by a second layer of SMA sheets, programmed to reflect the sun on hot days and allow it in on cooler ones, rendering the structure responsive. Nestled between the trees and greens the installation will seem to breathe life with its responsive “leafs”.

ABOVE Dragonfly in obelisk Position MIDDLE Wing corrugations BELOW Wing gradient coloration LEFT Close up of proposed skin

7

Module Design Dragonflies, have a complex network of hierarchical veins that provide stiffness for the wing and subdivide it with Voronoi tessellations into hundreds of small, simple shapes. The shape and position of these secondary veins vary endlessly, generating unique patterns on each individual wing, yet most of which are either 4, 5 or 6-sided polygons. For the design of the modular system, the geometry is simplified and the pentagon shape is used for the base unit. The dragonfly’s obelisk position is interpreted through a second layer, also pentagonal, that would be offset from the base at a variable distance. The spontaneous change of wing coloration in response to heat, resulting in variable degrees of shade, inspires the use of a Shape Memory Alloy (Copper based), that would be programmed to flatten out when temperature rises blocking the sun and curl up when temperature drops.

ABOVE 1:1 Prototype of 3 modules BELOW Diagram showing responsiveness

8

Growth pattern A regular pentagon cannot tessellate without either leaving gaps or having to deform its shape. The formal logic for arranging the units departs away from the regular enclosed space and uses branching and folding as space generating techniques following the creases found on dragonfly wings. Modules attach edge to edge, folding systematically at 30, 45 and 60 degrees. Unit distribution, density and angle is based on the site’s average exposure to the sun. A solar analysis at the said location informs the overall distribution of the units.

The area most exposed to the sun has the highest density of units. Modules are folded to optimum angles facing the sun. Shading, or the lack thereof, is then determined by the spontaneous transformation of the SMA. This passive behavior of the SMA coupled with the animated overall form, offer a dynamic experience as if the structure were alive.

ABOVE Branching/folding skeleton following solar analysis BELOW Final model in context

9

10

11

12

2/ WATER HARVESTING TENSILE STRUCTURE Student: Ali Mzannar Proposed location: Eyl, Somalia

A water harvesting pavilion draws principles from the behaviour of water on different types of hydrophilic and hydrophobic surfaces found in nature.

The pavilion is conceived as a prototype to be located in parts of the world suffering water scarcity. Research begins by studying water collection techniques found in each of the: Texas horned lizard, darkling beetle, and cactus spine.

The darkling beetle of the Namib deserts survives in one of the world’s driest climates. To collect water from dew and fog, it uses its body surface structure comprising a series of bumps and valleys. Water slides on the hydrophobic surfaces of the bumps and condenses in the valleys where a hexagonal microstructure helps direct water to the mouth. Similarly, the thorny devil adapts to limited water resources by passively collecting moisture through its spiky body surface. Dew condenses on the spikes and water is canalized through grooves to the lizard’s mouth by a capillary action system within its skin. Cactus spines harvest fog and humidity through gradient grooves on their conical surfaces by means of Laplace pressure difference.

ABOVE Darkling beetle (fog-basking) MIDDLE Texas horned lizard BELOW Cactus spines LEFT Close up of proposed skin

13

Water Behavior Studying the physical properties of the three examples delineates the impact of surface structure and chemistry on the behaviour of water. The following physical phenomena are extracted: Capillary action- the ability of a liquid to flow in narrow spaces without the assistance of external force like gravity.

Adhesion/cohesion forces- adhesion is the property of different molecules or surfaces to cling to each other. Cohesion is the property of like molecules to stick to each other due mutual attraction. Laplace force- the tension of the surface applied on a fluid in relation to the surface area and the radius of a cylindrical form. The combination of these physical properties suggests a surface that, with its morphology and material composition can collect, retain, and channel water efficiently.

ABOVE Capillary action, Adhesion/Cohesion, Laplace Pressure difference BELOW An early concept model of the skin system

14

Module Design Inspired by the hexagonal morphology of the thorny devil’s water channel network structure, the module takes for a base a hexagonal geometry, a shape well suited for tessellation.

A funnel shape is then created within an apparatus setup, by stretching the hexagonal membrane from the centre. Pulling the centre to variable heights affects the module’s overall proportions and radii which eventually allows for a total water condensation and channelling control. The fabric is then coated to perform as a hydrophobic surface. Alternatively, a composite textile comprising elastic filaments within a matrix of hydrophobic fibers may be used for the same purpose. The funnel shaped modules maximize area of contact with the air while optimizing water condensation with their variable height property.

ABOVE 1:2 Prototype of 5 units MIDDLE Concept diagram BELOW Drawing showing adjustable height

15

Site the project is located in the hot town of Eyl in Somalia, one of the countries facing increased water shortage. According to a study by Unicef, a child in Eyl would go up to 20km in order to get clean water. In addition to the need for a proper water source, the city has high humidity levels being near the equator, making it an ideal location for the structure.

ABOVE Final model BELOW Child travels long distances for clean water OPPOSITE TOP Diagram explaining form generation OPPOSITE MIDDLE Sectional drawing OPPOSITE BOTTOM Final model

16

Form Finding The design development of the skin system resulted in a continuous exoskeletal double skin system comprising 3 layers: an irregular hexagonal base frame, a polyester mesh layer taking the form of tensioned fabric, an irregular triangular grid connecting the hexagon centres elevated to variable heights. Inspired by the fog-basking behaviour observed in some species of the darkling beetle where it would lift its rear end up to face the foggy wind, the pavilion surface is manipulated in a form finding process, to maximize area of contact with humid air. Starting with a square surface, 2 arched openings are introduced giving access to the interior space. The vertex facing the direction of prevailing winds is then elevated enough to maximize water condensation. Water is then channelled by gravity to a reservoir.

17

18

3/ AERODYNAMIC BENDINGACTIVE STRUCTURE Student: Mahdi Hijazi Proposed location: Chicago, Illinois

This project looks at aerodynamic features found in natural organisms and applies principles extracted from their physical and behavioural properties in order to propose a skin system that can reduce the wind load affecting the structure while optimizing natural ventilation.

Biological systems have evolved a wide range of drag reducing mechanisms that have inspired the design of a range of products, from synthetic skins/ wearables to aircraft vehicles. In architecture, the aerodynamic properties of a structure make an important factor to consider during the design process due to the great impact of wind loads on the building’s structural performance and the importance of ensuring adequate and comfortable airflow inside of it. In this project, an aerodynamic modular skin system is developed by drawing from: shark skin, bird feather structure and flying snake body shape.

ABOVE Flying Snake MIDDLE Shark BELOW Bird in flight LEFT Close up of proposed skin

19

Research Flying snakes display aerodynamic characteristics that enable them to glide.

During flight, the snake flexes its ribs causing its body to morph its circular cross section into an elongated shape. The flattened body resembles a wide triangle with a rounded upper vertex and a slightly concave lower edge that acts as a lifting surface in the absence of wings. This new body geometry accounts for its aerodynamic properties that make gliding over a range of angles of attack possible. Shark skin is a well-known example of drag reducing skin with its riblet surface structure. On the skin are many micro scales named dermal denticles. Riblet geometry on these denticles is said to prevent vortices formation allowing water to move easily over the shark skin, due to its spanwise curvature. The fragmented configuration and variation in riblet size and shape along the surface of the body are optimized for maximum drag reduction.

Bird feathers are necessary for flight, insulation and courtship displays. The feather structure has barbs branching from the central shaft that have further branches called barbules.

The microscopic filaments have hooklets that attach adjacent barbs to each other like a zipper, stiffening the vane and forming a tight, smooth continuous surface. These strong linkages maintain the form of the feather and are necessary to withstand air resistance during flight.

ABOVE Flying Snake body cross section MIDDLE Shark denticles under microscope BELOW Bird feather barbules under microscope

20

Module Design A key aspect has been extracted from each precedent and translated into a design feature: The module comprises of 2 wood planks, curve bent, interlocked and slotted into steel rods. The skin module takes its curved geometry from the cross section of the flying snake. This form reduces wind velocity and impact as it slides gently along the structure’s fragmented surface. The wooden parts have variable depths and curved edges inspired by shark riblets. The lower unit extends beyond the limit of the upper, directing the wind into the pavilion space to create a circular air stream. Adjacent modules are stacked, slotted, into the same bars in an alternating manner. This interlocking system draws from the interlocking mechanism of barbules, stiffening the overall structure. This structural solution contributes to the overall strength of the structure. The modules retain flexibility of movement as shark denticles are loosely embedded in the skin and bristle in motion.

ABOVE 1:1 Prototype of 3 modules MIDDLE Assembly detail BELOW Module variations

21

22

Site The selected site is Maggie Daley Park, a public park near Lake Michigan, Chicago. Famed for its bold architecture and high rise building, the so called ‘windy city’ scores high wind speeds especially in the bay area facing Michigan.

Form and Performance The proposed pavilion resists and channels the winds generated by Michigan lake. The form of the pavilion is defined by a series of bent steel rods fixed at both ends. The simple structural system allows a formal versatility so that the overall geometry is organic. The pavilion hence works as a shell structure that takes its shape upon fixing its ends to defined borders. The variable rod lengths create variable interior heights and account for a dynamic spatial experience.

The units act as shading elements in addition to being aerodynamic. Following wind and solar analysis on the designed structure, the units are distributed such that: they are dense where the sun hits the strongest and are loosely spread apart where it’s not. The variable depth of the units is determined by the required airflow inside the pavilion.

The breathing structure prevents uplift and reduced resistance through its many openings.

Computing all the variables of the system combined generates a performative structure whose skin performance is optimized for sun and wind.

LEFT Final model

23

24

4/ REPTILE SKIN-INSPIRED PAVILION Student: Hassan Kobeissi Proposed location: Bavarian Forest, Germany

This project explores the variable properties and functions of scale-covered reptilian skin.

In most snakes and lizards, skin comprises of overlapping scales arranged in rows. This type of overlapping arrangement offers protection against predators and potential injury, as well as allows for flexibility of movement. In addition to its defensive function, the tough outer layer helps reptiles survive hot and dry climates by preventing them from losing water.

Reptilian skin patterns and textures vary according to species. In this project, different types of scales are catalogued and studied in terms of: geometry, size, color and tessellation patterns. A close up view of reptile scales reveals a gridded corrugation, a surface triangulation alternating darker color shades and lighter tones. This is due to the secretion of an oily substance that helps protect the reptile from the heat by reflecting sun rays so that the skin absorbs 20-30% heat in desert climates, 30-40% in tropical climates, and 40-60% in temperate climates. The skin structure observed in reptilian skins offers great inspiration for the design of a modular skin system that is both robust and resilient.

ABOVE Colorful Lizard head MIDDLE Snake skin BELOW Scale surface triangulation LEFT Close up of proposed skin

25

ABOVE Top view of the model BELOW Solar analysis highlighting 3 zones

26

The design interprets scale tessellations and micro triangulation through a system of diamond shape metal sheets folded and interlocked with one another through slits on the sides. The tip of the module is stretched to varying extents offering greater shade, leaving the interlocked array unaffected. A solar analysis at the chosen site identifies 3 degrees of sun exposure.

Modules are varied and distributed accordingly such that the longer ones are placed where sun exposure is maximum.

Form Finding The units are first connected to each other flat, forming a continuous corrugated surface. The continuity of the skin allows flexibility of movement while the folding offers an additional degree of structural integrity. The result is an airy, faceted skin surface that can be shaped and optimized following site and environment conditions.

Hence, to generate the final form, the surface is manipulated such that the structure features an inviting indirect entrance and the space gradually grows in height to open up completely towards the mountainous view. A concrete foundation acts as viewing platform. The shell takes its form as the base edges are fixed to the ground.

ABOVE Elevation BELOW Model showing pavilion entrance

27

28

Site The selected site is the Bavarian Forest in Munich. The touristic site remains one of the largest protected forest areas in central Europe. The pavilion is proposed on one of the several resting points along the hiking trail.

The spatial qualities of the design are explored in physical model and experienced within a virtually simulated environment.

LEFT Virtual model shows pavilion in context RIGHT Images of model showing varying degrees of visibility

29

30

5/ FOG AND MOISTURE COLLECTING BAMBOO STRUCTURE Student: Yara Fakih Proposed location: Siem Reap, Cambodia

Nature has evolved species which can survive in arid regions using efficient water harvesting techniques. This project studies the physical and behavioral properties that account for water collection from the environment in each of the: pine cone, thorny devil and cactus spine.

The thorny devil harvests water through its hydrophilic spiky surface and channels it through grooves to its mouth by a capillary system within its skin. This gravity-defying system enables the thorny devil to absorb water from rain or soil moisture. The pine cone is a common example of passive responsiveness to changes in relative humidity. When dry, its scales open and release seeds; when damp, they close. This is due to the bilayer structure comprising of an outer layer of thick walled, water absorbing cells that expand when exposed to humidity and shrink when dry.

The differential expansion of cells accounts for the open/close mechanism. Cactus spines harvest fog through gradient grooves found on their conical surfaces by means of Laplace pressure.

Water condenses and is collected on the tip, then transported to the base where the radius is larger and Laplace pressure is smaller. It is then absorbed into the stem upon contact with the trichomes.

ABOVE Pine cone with half open scales MIDDLE Thorny devil on sand BELOW Cactus spines LEFT Close up of proposed skin

31

Module Design Inspired by the pinecone scales’ doubly curved geometry and varying curvature upon opening/ closing, the module takes a saddle shape defined by a doubly ruled surface. The ruled frame is made with straight bamboo sticks supporting a layer of mesh polyester fabric cut out in diamond shapes following the surface diagrid subdivision. The sticks fan out, extending beyond the frame from two sides resembling cactus spikes. The mesh acts as a hydrophilic water harvesting surface onto which atmospheric water vapour from rain, fog and dew condense. Water droplets trickle down to the sides where it’s channelled through the main structure down to a reservoir. The diamond shaped modules vary in curvature to create varying degrees of opening. Depending on its location on the surface, module curvature is determined by area of contact with the wind and optimized accordingly.

ABOVE Prototype of 5 modules showing varying degrees of curvature MIDDLE View of module underside showing ruled base frame BELOW Close up of mesh layer LEFT View of aggregated units

32

33

Form The overall form of the pavilion is a scaled up version of the module. The diamond shaped modules would hence tessellate within the subdivisions of the hypar. The doubly ruled surface providing a base for the panelling is constructed from straight bamboo beams.

Different types of bamboo may be used for the structure; long and thick walled bamboo is flexible and can be bent while retaining its strength and durability. To create a more dynamic experience, the hypar structure is slightly tilted and one of its tips elevated exaggerating the opening from one side. The module variation, inspired by the pine cone pattern, optimizes water condensation on the mesh. The airy structure prevents uplift by reducing impact of wind loads.

Site The proposed site is located in Siem Reap, Cambodia, in the vicinity of the iconic Angkor Wat, the world’s largest religious monument.

The touristic site is selected based on its high humidity as well as the abundance of bamboo as a locally sourced building material traditionally used for ages.

ABOVE Top view of model MIDDLE Surface curvature and water condensation diagram BELOW Collage of structure in context

34

Performance The structure would hence serve as an example of how traditional construction methods may be used to build contemporary performative structures. An environmental study of the site informs the orientation of the pavilion such that wind blows in the direction of the elevated tip. This creates greater contact with prevailing winds carrying moisture from the nearby lake. As water evaporates over the water body nearby, wind carries water particles to condense against the structure’s surface. The modules degree of opening increases towards the tip for the same reason.

ABOVE Close up of tessellated modules BELOW Skin Layers: base structure, module frames, mesh fabric

35

36

6/ AIR PURIFYING PAVILION Student: Fatima Zanguy Proposed location: Ancient city of Babylon, Iraq

This project looks at examples of organisms with unique filtering mechanisms to propose an air purifying structure particularly suited for desert contexts. The proposed skin system is primarily responsive to wind, its function to remove solid contaminants such as dust particles, improving air quality in and around it.

The proposed pavilion structure takes its inspiration from: barnacles, krill and fungi.

Fungi play an important role in the balance of the ecosystems as decomposers and recyclers.

They filter the surrounding environment and consume small particles with overlapping plates radiating vertically on the inside of their gills. The krill filters and cleans the water with its filtering basket legs as it feeds by compression pumping: during the expansion of the feeding basket, water and particles are sucked in from the front; once inside, the particles are retained on the filter and water is expelled from the sides. Similarly, food particles are caught and water is filtered through the barnacle’s filter feeding apparatus as it forms a cup-shaped fan when spread.

ABOVE Fungi gills MIDDLE Krill filter legs/ feeding basket BELOW Barnacle feeding legs/ cirri LEFT Close up of proposed skin

37

Module Design The project interprets the fungi plates as thin sheets of a filtering material radiating normal to the shell’s surface comprising the skin. There is a second layer of biomimicry in the structural system inspired by the krill’s body structure (filter legs) and comprising of a series of bent rods forming a continuous surface. The overall form draws from the smooth curvature of the barnacle’s fan. The module is comprised of a series of overlapping, “filtering plates” of variable spacing. The material proposed is one that is used in airfiltering applications. The built prototype uses felt material as an example of such material in addition to its good heat insulating and waterproof properties. Sheets are laser-cut to have a wavy border on the outside and a subtler curvature on the inside. The stacked sheets alternate the wavy edge, maximizing dust capturing surfaces while creating a textured feel. Adjacent modules attach to each other by overlapping sheets from either side.

Defining the overall form of the structure are bent steel rods through which the felt sheets are slotted and fixed.

ABOVE Diagram showing module variations BELOW 1:2 Prototype of 4 “modules”

38

Form The simplicity of the framing structure ensures a degree of flexibility of the base form which in turn allows for freeform design that can be optimized to respond to site and environmental conditions. The density of plates and spacing between them vary in a gradient manner according to exposure to wind. To optimize the air filtering performance of the skin, a wind analysis is conducted and the plate distribution is determined such that they are closely arranged where the structure is exposed to high winds and loosely fit where wind level is low.

ABOVE Final model BELOW Close up of undulating form

39

Site The structure is located in the Iraqi desert, at the entrance of the ancient city of Babylon. The pavilion is proposed as resting point for tourists situated at the base of one of Babylon’s archeological hills, an artificial mountain made from the collapse of ancient cities. The wind analysis at the selected site shows that the wind direction changes from day to night from Southeast to Northwest. The site is visited during the day for nearby archaeological sites and during the night for star gazing.

As a result, the pavilion takes an S shape for a dual functionality and enables the use of the space throughout the day.

ABOVE Model showing design concept LEFT Model showing interior

40

41

42

7/ HEAT ABSORPTION THROUGH RADIATION Student: Mohamad Akkoush Proposed location: London Tower, London

Flying insects require energy for flight. Several have evolved behavioural and physical features that enable them to warm-up before flight making this energetically demanding activity possible. One example is the Rose Butterfly, native to Southeast Asia. Since it is cold-blooded and needs sunlight to fly, its black wings have evolved to be very good at absorbing energy.

This efficient property of butterfly wings to absorb light has compelled scientists to study their diverse nanostructures triggering the proposal and design of thin, more efficient solar cells. Studies show that ultra-black butterfly scales are widespread and morphologically diverse. A view of the tiny wing scales under the microscope shows that they comprise of expanded trabeculae and inverse V ridges that minimize surface reflection and maximize absorption of light by creating a sparse material with a high surface area. The system of variably sized holes spanning ridges running the length of the scale help scatter the light and help the butterfly absorb heat regardless of the angle of exposure.

ABOVE Black butterfly basking MIDDLE Butterfly wing scale under the microscope BELOW Cross section of a scale with closely arranged ridges LEFT Close up of Skin System

43

Module Design Inspired by the butterfly basking position and inverse V ridges on its scales in their role in maximizing solar exposure and heat absorption, the module developed is a metal sheet folded at 120 degree angles. Based on material’s energy absorption percentages, aluminum composite material was selected.

To further absorb heat in larger amounts, the module is pained in black. The underside is painted white so as to help reflect sunlight within. The initial shape is an L, given that once it is tessellated, the resultant surface retains a ridge architecture. To reflect sun rays into the space, cut-outs are introduced and folded at variable angles. reflectors enhances the amount of sun entering the space. The angles ensure that the flanges continue to work throughout the day as sun angle changes. The openings admit light, air and direct heat and warmth. the flanges reflect sun into the space or back onto the skin surface to absorb the

44

Form/ Site Tessellating the zig-zagging L shape limited the possibilities of the overall form and forced a uni-directionality. Connecting the units at the vertex instead allows fluidity of form and amplifies skin performance. The selected site is in the green areas of the Tower of London. The pavilion’s oriented such that sun absorption is optimum and amount of energy transferred into the space. Once the sun’s radiation hits The structures surface, the rays are absorbed, reflected, and/or transmitted. Transmitted through the cuts, the folded plates will reflect the sun radiation in different directions based on angle of fold, scattering them inside the space. The surface is optimized to transmit radiation into the space and store the heat obtained by the sun at the same time, preserving it for a longer duration.

LEFT TOP Diagram of skin system LEFT BOTTOM Modules arranged in initial ridge structure ABOVE Scale model of the proposed pavilion BELOW Close up of the skin system

45

46

47

REFERENCES Michael Pawlyn. Biomimicry in Architecture, Riba Publishing, 2011 Blaine Brownell. Hypernatural, Architecture’s New Relationship with Nature, Princeton Architectural Press, 2015 Veronika Kapsali. Biomimicry for Designers: Applying Nature’s Processes and Materials in the Real World, Thames & Hudson, 2016 M. Addington, D. Schodek. Smart Materials and Technologies. London, The Architectural Press, 2005 Biomimicry, an Approach, for Energy Efficient Building Skin Design by Gehan.A.N. Radwan, Nouran Osama Mazzoleni, I., 2013.

Architecture follows nature- Biomimitic Principles for Innovative Design. CRC Press.

Hoeven, M., 2012. Technology Roadmap: Energy Efficient Envelopes. (Online) Retrieved from http://www.iea. org/publications/freepublications/publication/TechnologyRoadmapEnergyEfficientBuildingEnvelopes.pdf Zari, M.P. 2007. Biomimetic Approaches to Architectural Design for Increased Sustainability. Sustainable Building Confernece. Auckland Links http://www.asknature.org/ http://www.biomimicry.net Image References Cuttlefish skin diagram https://www.sciencefriday.com/educational-resources/cephalopod-camouflage-beauty-thats-skin-deep/ Cuttlefish https://oceanbites.org/cuttlefish-freeze-out-their-predators/ Dragonfly basking https://michaelqpowell.com/2019/06/22/amber-obelisk/ Dragonfly wing https://www.washingtonpost.com/lifestyle/home/nature-got-the-dragonflys-primitive-designright--and-even-astronomers-are-taking-note/2015/08/24/33763f70-4769-11e5-8ab4-c73967a143d3_story.html Dragonfly wing pigments https://www.flickr.com/photos/lrkirsch/6012860446/ Darkling beetle https://asknature.org/strategy/water-vapor-harvesting/#jp-carousel-73068 Cactus http://www.sbs.utexas.edu/mauseth/researchoncacti/Spines.htm Thorny devil https://www.abc.net.au/news/science/2016-11-03/how-the-thorny-devil-gets-a-drink/7987598 Flying snake: https://www.charismaticplanet.com/chrysopelea-flying-snake/ Shark: https://www.forbes.com/sites/melissacristinamarquez/2019/03/04/spilling-the-secret-to-a-mako-sharksspeed/#67fa48ff1e02 Bird: https://news.usc.edu/files/2019/11/Taiwan-Blue-Magpie-web-824x549.jpg Snake cross section: https://www.researchgate.net/figure/a-e-Cross-sectional-shapes-tested-in-this-study-depicted-at-scale-The-half-full_fig1_226690809 Shark skin detail https://www.reddit.com/r/comments/8aydcq/shark_skin_135x/ Feather hooks https://www.pinterest.com/pin/464152305326543929/ Reptile https://p0.pikist.com/photos/847/345/lizard-colorful-head-view-exotic-reptile-scale-animal-close-upthumbnail.jpg Reptile skin https://www.pinterest.cl/pin/82824080617824946/?autologin=true Reptile abstract http://3.bp.blogspot.com/--0Vce0uZxL0/ViLrBvzsheI/AAAAAAAAZHY/62Z_ds_9k2k/ s1600/921-d-abstract-seamless-snake.jpg Pine cone https://www.pexels.com/photo/close-up-photography-of-purple-tubular-plant-during-daytime-163710/ Mushroom https://www.savoirflair.com/beauty/350201/mushrooms-benefits-dr-andrew-weil-origins Krill https://www.blue-growth.org/Fishing_Over_By_Catch/Krill.htm Barnacle https://www.quora.com/What-is-the-difference-between-a-limpet-and-a-barnacle Butterfly https://pixnio.com/fauna-animals/insects-and-bugs/butterflies-and-moths-pictures/wildlife-nature-animal-fern-insect-black-butterfly-herb-flower

48

49

50