Biomimicry for Sustainability: Improvement of Building Skin with Nature-Inspired Innovations

*Güneş Mutlu Avinç and Semra Arslan Selçuk* 

#### **Abstract**

Energy efficiency and related concepts of it for sustainability in architecture are the important issues of the twenty-first century architecture and "nature" has prospective ideas in terms of sustainable design. Buildings can be designed, constructed, and operated in a "holistic approach" according to the principles extracted from nature. Thus, "innovative design approaches learned from nature" is one of the most important architectural manifestos of today. This chapter focuses on the intersection of "biomimicry" and "building envelope" to discuss the skin/skin functions of organisms in nature and biomimetic design approaches in building shells as an energy management instrument. In order to examine how different skin/shell functions in nature have been transferred to the building shell, the pioneering studies in the literature have been examined and a comparison has been done to figure out functional similarities between skin of the natural organisms and the building facades. Selected studies are conceptual or applied projects and designs that are inspired/learned from different natural skin or surface characteristics in different climate regions. As a result of the evaluation, biomimetic building shell designs have been found to provide energy and resource efficiency without active energy use that can be seen as the most vital sustainable design criteria.

**Keywords:** sustainability, biomimicry, bio-skin, building envelope, facade

#### **1. Introduction**

 Although it is as old as human history, scientific conceptualization of the biomimetic approach began in the twentieth century. Biomimetics having been constructed on natural references is leading the development of many innovative ideas and practices in the field of architecture. Biomimicry imitates the forms, systems, and processes found in nature to solve the most important problems our world is facing and to produce sustainable solutions [1]. Vincent [2] defines this approach as "abstraction of a good design in nature."

So far it is observed that the biomimicry has potentials for sustainability and energy issues, particularly in the design and construction field [1]. With this approach, the deepening nature of perception provides new perspectives on the development of sustainable approaches to the scientists who are conducting research in the field of architecture. Thus, these developed sustainable approaches are included in the literature as a product of interdisciplinary studies, especially

biology, architecture, and technology. Since nature has experienced what works and what is appropriate for thousands of years [3], taking nature as a mentor can play key roles in achieving "sustainable designs." Demands for sustainable approaches in the building environment are increasing day by day. One of the main reasons behind this is that the vast majority of global environmental and social problems in the world is largely related to waste, material, energy use, and greenhouse gas emissions as well as the built environment [4].

The most important element affecting the sustainability in the built environment can be considered as the energy efficiency of the building and the climatic comfort of the users is the building shell [5, 6]. Facing many problems such as natural forces, solar effects, and humidity, the structure shell has similarities and common points with the living skin/shell in the natural environment. Many studies conducted in recent years claim that the return to nature and learning from its best ideas have potential to produce innovative solutions and they analyze the live skins to find effective answers to the problems related to building shells [7–9]. From the results of these studies, it is understood that the adaptations that enable the living creatures to survive in their habitats contain solutions that can be converted into design for adaptive building shells.

Within the scope of this study investigating the sustainable building shells, firstly, the design criteria for sustainability in architecture have been explained and then the functional properties of different skins, especially the skin of human skin and polar bear have been investigated. Then, the building shell/envelope designs which were realized by learning from these natural structures have been examined. Within the light of the data obtained, it is seen that nature-inspired ideas provide energy efficiency in the design of sustainable facades.

#### **2. Prominent design criteria for sustainable architecture**

 In every period of its existence and conditions, the concept of sustainable architecture, by considering future generations, can be defined as designing and implementing structures that use energy, water, material, and land effectively, prioritizing the use of environmentally sensitive renewable energy resources and protecting the health and comfort of people. In other words, it is the architectural design and applications that aim to meet the space requirements of people without endangering the existence and future of natural systems [10].

In this architectural approach, future generations are considered, and the design of local, social, economic, cultural, and environment-friendly structures are emphasized. In this context, firstly, the amount of energy used in buildings should be minimized (the amount of energy spent during construction, use, and demolition), passive design strategies should be used, HVAC and the use of energy consuming systems such as artificial lighting should be reduced, and the construction should be designed in accordance with the local climatic characteristics of the region [11].

The main purpose of sustainable design is the harmless existence of naturehuman association. In this context, the basic principles for a sustainable design can be listed as follows:


*Biomimicry for Sustainability: Improvement of Building Skin with Nature-Inspired Innovations DOI: http://dx.doi.org/10.5772/intechopen.87836* 


 It is necessary to think on how the shell should work for the sustainability of the building shell. In this case, absorbing, collecting, or evaporating to regulate humidity; dissipating, gaining, or conserving to regulate temperature; filtering or exchanging to regulate carbon dioxide (air quality); reflecting, absorbing, redirecting, or diffusing to regulate light [5]; and in addition to these acts in response with the environmental conditions, not harming the natural environment, integrating action with nature gained prominence.

Sustainability is the fundamental principle of nature, and the design criteria listed above are seen in all ecosystems in nature. Animals, plants, and other organisms have survived and improved themselves heretofore because of the efficiency of source and produced waste. Therefore, imitating the forms, systems, and processes of nature offers an opportunity to maximize the resource efficiency while mitigating the negative impacts of buildings on the environment [3]. In this context, nature is seen as a source of innovation in the creation of sustainable architecture. At the same time, the biological information to be used for the design solution is transformed into architectural terminology.

#### **3. Looking to the ideas of nature for sustainability and biomimetic building skin design**

#### **3.1 Natural skin**

Human skin and animal skin/shells contain many potential ideas for natureinspired designs. These surfaces, which act as connecting elements between indoor and outdoor environments, fulfill many vital functions such as adaptation to environmental conditions, protection, and permeability. As well as, it has many features such as heat loss-gain, water balance, evaporation, temperature regulation, and color change for communication purposes. Because of these features, it inspires architectural shells and facades. In this context, in order to realize the designs which can be called "biomimetic buildings shell," firstly, the skin/shell formations in nature should be examined and the skin/shell functions and structures related to the living beings can be converted into data that can be transferred to the architecture.

If it is necessary to mention human skin which are natural skins, firstly, this layer that covers the whole body consists of three layers: epidermis, dermis, and hypodermis. Epidermis is a thin surface layer that serves as a protection. Just below the epidermis are mechanoreceptors that provide mechanical sensations such as touch, pressure, temperature, and pain. Receptors that detect pressure, vibration, and temperature are close to the skin surface (**Figure 1**) [13].

The skin also functions to regulate the temperature balance of the body. Functions such as transmission, transport, radiation, and evaporation are carried out to regulate the body temperature. Evaporation throws heat from the body to the warmer environment with the help of pores of the skin [15]. Thus, human skin structure that has many tasks such as regulating the body temperature, evaporating the water to provide moisture balance, to protect from outside effects can be transferred to the structure of the shell. In order to use these principles as an architectural information, the question of how and wherein each feature takes place is important.

**Figure 1.**  *Human skin anatomy [14].* 

 On the other hand the body temperatures of polar bears are kept constant at 37°C, and in the north pole with a temperature down to −40°C by their furs, which consist of two separate layers that are the dense substrate close to the skin and the longer, the thick outer layer. The hairs in these layers are transparent and appear to be white because they emit sunlight. On the other hand the black epidermic layer on the oil layer provides the maximum absorption of solar radiation [16]. Heat loss occurs only in the eyes and mouth of the polar bear (**Figure 2**) [17]. As it is seen, the polar bear's morphological and physiological structure acts as an insulation that protects it from cold weather conditions.

In summary, when the living systems are examined, important physiological and morphological information is obtained about how to control the temperature. In this context, this information is used in building envelopes and facades to ensure thermal comfort, energy efficiency, and sustainability.

**Figure 2.**  *Polar bear fur [18].* 

#### **3.2 Building envelopes and bio-facades in architecture**

Architectural constructions are traditionally static structures and have limited capabilities to detect and adapt to their environmental conditions. The building shell is generally solved by the joining of the stationary elements and is designed as an interface that provides the function of protecting the indoor environment from the external environment. Kieran and Timberlake [18] define the building shell as the surface where the material and energy exchange takes place. Building shells are one of the most important design parameters that determine the interior physical environment related to visual comfort, thermal comfort, and usage time efficiency. Therefore, they directly affect the energy use in buildings. Buildings activated by mechanical devices may cause the building to remain insensitive to the environment. They make heating-cooling with these devices and do not interact with the external environment. Thus, buildings do not respond to changing climatic conditions and cannot be adapted to their environment.

Innovative building shells are designs that look for adaptivity and interaction to actively respond to current climatic conditions to improve indoor comfort conditions and building energy performance [19]. In this context, in order to develop

#### *Biomimicry for Sustainability: Improvement of Building Skin with Nature-Inspired Innovations DOI: http://dx.doi.org/10.5772/intechopen.87836*

 environmentally sensitive, ecological, and sustainable building shells in recent years, the skins/shells in nature are investigated. For example, the flexibility and sensory adaptability of human epithelial tissue cells are biologically examined to develop materials and forms to develop adaptive structure coatings. With the"eSkin" project, which defines a transition from nanoscale to macroscale, it is aimed to reduce energy use in buildings, to produce responsive adaptive building materials and sensors (**Figure 3**) [20].

 In another study, a composite material based on the perspiration of human skin is produced by the Spain's Institute for Advanced Architecture of Catalonia (**Figure4**). This material is hydroceramic consisting of clay, fabric, and hydrogel. The clay surface is filled with a plurality of cavities providing sufficient space for expansion of the hydrogel components. The results of an experiment with a small-scale prototype showed that the system is reduced to the temperature in an interior by five degrees [21]. The cavities in the material responses like human skin by opening and closing against humidity change. The material used over here being sensitive to the humidity can be opened and closed in response to air changes and act as an autonomous system sensitive to ambient conditions. This system has created a sustainable adaptive architectural shell that is designed based on biomimetic principles that do not require any sensors or electrical systems.

 In another study, it was learned from the physiological adaptation of polar bear in the adaptive sustainable architectural shell design which is sensitive to sunlight and able to provide thermal regulation (**Figure 5**). The living units, which are designed as partially embedded, are considered in the south-west direction to optimize the heat gain from the sun. Solar heat and light are collected by the active shell, which consists of rotatable hollow fur-like glass tubes, and the heat and light that are stored along the tube, and slowly released, are transmitted to the insulation layer. In addition, phosphorous cells embedded in the phase-shifting material allow the light to be emitted slowly at night [22].

**Figure 3.**  *Epithelial tissue and eSkin project [20].* 

#### **Figure 4.**

*A prototype composite material created from the perspiration properties of human skin [21].* 

**Figure 5.**  *Building skin inspired by polar bear [22].* 

In this study, which was designed according to the physiological and morphological characteristics of bear fur (**Figure 6**), thermal insulation was investigated for building shell. A biomimetic design has been developed using recyclable materials and bio-based materials based on the thermal functionality of the polar bear's skin and morphological properties of the polar bear's fur. The polar bear's features including heat radiation reflection, heat insulation, solar radiation, and black absorbing skin gave a direction to design [23].

#### **Figure 6.**  *Prototype of the concept [23].*

The Techtextil Prize-winning "Polar bear pavilion" is a sustainable example based on the polar bear (**Figure 7**) [24, 25].

 The Denkendorf Institute of Textile Technology and Process Engineering (ITV) has produced a self-supporting textile membrane for energy. Researchers have produced a system that stores the thermal energy by taking into account the function of the polar bear's fur and the different characteristics related to fur during the design stage [24].

As it can be seen, the use of heat and light features of the polar bear's fur has resulted in different ways in three different projects. In the same way, two different projects have been seen which are based on the characteristics of human skin. The design principles outlined in these studies are summarized in **Table 1**.

#### **Figure 7.**

*Energy-efficient textile building with transparent thermal insulation for the solar thermal use according to the model of the polar bear's fur [26].* 


#### *Biomimicry for Sustainability: Improvement of Building Skin with Nature-Inspired Innovations DOI: http://dx.doi.org/10.5772/intechopen.87836*


*Biomimicry for Sustainability: Improvement of Building Skin with Nature-Inspired Innovations DOI: http://dx.doi.org/10.5772/intechopen.87836* 

#### **4. Conclusions**

In order to obtain a sustainable built environment, nature-adaptable and sustainable structures are needed. In order to create this cycle, it is necessary to apply the working principles of nature and integrate the obtained data into the design. It has been observed in the examples analyzed within the scope of the study that the shell design, water/humidity balance, communication and thermal regulation properties, sustainable architectural shell systems, or shell materials that are integrated with nature have been obtained by transferring the good ideas learned from nature to the building. The obtained products can be adapted to ambient conditions such as light, temperature, and humidity. The main objective of the sample studies examined is to produce solutions for adaptation, performance, and sustainability issues in architecture and to design environmentally sensitive shells. The common denominator of all studies is that it is being carried out in interdisciplinary platforms continuing in the fields of biology, architecture, and engineering. At the same time, the dynamic/physiological/morphological features of living things are investigated on a nanoscale and transferred to a macroscale. As a result, it is seen that innovative solutions have been introduced via the samples examined in this study based on the principles learned from the "organism level" in nature by using biomimetic approaches. Thanks to these studies, architectural design research integrates with laboratory-based scientific research and accelerates "sustainability in architecture" studies.

### **Author details**

Güneş Mutlu Avinç1 \* and Semra Arslan Selçuk<sup>2</sup>

1 Department of Architecture, Muş Alparslan University, Muş, Turkey

2 Department of Architecture, Gazi University, Ankara, Turkey

\*Address all correspondence to: gunesavinc@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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**51**

**Chapter 5**

**Abstract**

cultural influences

**1. Introduction**

Smart Buildings in Relation to

Human Behavior and Cultural

Technology has been dominating the world for a while now, buildings included;

seeking in part human's welfare, comfort, and security, in addition to resources conservation. Thus, it created Smart and High-Tech architecture that integrated with sustainability evolving the Eco-Tech buildings. In theory, all smart buildings with their advanced technologies can accomplish a lot, however, in the application, human behavior and cultural influences can either make the theory succeed or fail. Hence, this chapter aims at exploring the effect of these two factors on the level of success of smart buildings. This will be achieved throughout analyzing the Egyptian

**Keywords:** sustainability, smart buildings, human behavior, Egypt smart buildings,

Living in an era of widespread and ongoing extreme technological revolution, had its effect on the building industry. This wave of smartness allowed technology to take part in architectural design since the middle of the nineteenth century [1], creating intelligent, smart, and high-tech buildings. It expanded to include green and sustainable buildings, when they combine technology with living needs and environmental requirements, thus striving to meet high-performance considerations [2]. Actually, various architects were stimulated with smart buildings only for the sake of achieving sustainability [3]. This integration created the echo-tech architecture, as will be further explained. In the future, smart buildings aim at developing self-sustaining and totally automated buildings to meet the increasing demand for energy together with others cultural, environmental, and human needs [2].

While normal buildings, annually, become 3–5% less efficient; smart buildings should maintain a high-performance level, thus require smart users and smart operators [4]. Occupants spend around 80% of their living time inside buildings [5]. Thus it is crucial to engage them with the building allowing them to control their environment in order to be safe, comfortable, and sustaining a high-performance operation as well. Additionally, these buildings can monitor and analyze how occupants conduct within them [6]. They contain smart sensors, systems, and materials within buildings, which is the latest and most advanced technology [3]. For example, they use automated systems which control the internal environment

Influences in Egypt

experience and studying some of its smart buildings.

and can communicate with occupants [7].

*Reham M.M. Mohie El-Din*

#### **Chapter 5**
