Architectural Science and the Sun

The poetics and pragmatics of solar design

Dason Whitsett, Matt Fajkus

• Editorial: Routledge
• Año: 2018
• ISBN:
  9781317481669
• Edición: 1
• Categoría: Architektur
• Categoría: Nachhaltigkeit in der Architektur

Architectural Science and the Sun synthesizes physics, climate, program, and perception to provide a foundation in the principles of architectural science related to the sun: solar geometry, solar analysis and design techniques, passive design principles, and daylighting. Part analytical handbook, part inspiration source for schematic design, the content comprises a critical component of effective sustainable design.

Beyond the purely technical aspects of these topics, Architectural Science and the Sun begins with the premise that great architecture goes beyond energy performance and the visual-aesthetic to engage all of the senses. Given that the stimuli to which our senses respond are physical phenomena such as light, heat, and sound, the designer must manipulate these parameters through the craft of building form and technology to create the desired qualitative experience. This book is designed to help the reader develop that skill.

1
Introduction

Light and Existence: Trajectory of Light and Form

Our eyes are constructed to enable us to see forms in light … The key is light, and light illuminates shapes and shapes have an emotional power …

I use light abundantly, as you may have suspected; Light for me is the fundamental basis of architecture. I compose with light.¹

—Le Corbusier

Dependence on Daylight: Global Sustainability

In the broadest sense of the term “sustainability,” the sun is perhaps the most important ingredient to sustain life on Earth. The ability of design to adapt to the sun is critical to the very existence of any living being. Sun patterns and natural light have been a driving force in the development and prosperity of humankind. Our very understanding of the world around us is dictated by daily cycles and the specificities of our given climate, all animated by mysterious and awe-inspiring skies as the backdrop to our existence. The sun has been heralded for its many powers and meanings by the ancients (Figure 1.1), and even today we must appreciate the sun as the basis for all organic existence.

Light pervades our universe, literally and figuratively, yet it is often not at the forefront of architecture and spatial design thinking or everyday routines. As humans currently spend an average of 90% of their time indoors, natural light is often considered an indirect or supplemental asset, but not of primary importance to existence. Sunlight is not merely beneficial to humans; it is actually an absolute necessity.²

Thus, the design of spaces around us and how they embrace the sun is of paramount importance not only to our physical existence but also to our emotional and psychological well-being. Sunlight is elemental to vegetation and is just as important to the chemical balances of humans. A proper level of natural light is required to maintain physical health and to provide basic sustenance for all natural cycles on Earth.

Natural light has also been shown to have a direct connection to human health and productivity. Student performance is also connected to natural light, and is seen in test score differentials due to classroom light levels.³ Conversely, clinical light therapy is recommended by doctors to overcome depression and other illnesses related to a lack of proper daylight exposure. Rather than reaching this point, it is far more preferable to be preventative by designing space that carefully considers the sun and daylight to enrich and balance the lives of occupants.

Figure 1.1 Arizona petrified-forest petroglyphs of Anasazi origin, c. 700–1300 A.D.

Marilyn Angel Wynn/Nativestock Pictures

Historical Perspectives on Light and Vision

In order to appreciate our current comprehension of light, it is helpful to trace a trajectory of discovery from the past. Vision is one of the principal perceptual senses in humankind. It is understandable, then, that vision (and therefore light) has been pondered and considered by humankind since prehistoric times.

The story of light includes a history going back multiple millennia, in which humankind has struggled to understand it. Many ancient civilizations worshipped the sun or some type of sun deity, as Gary Waldman establishes and lays out a framework for.⁴ The development of a global comprehension of light and vision has not been a linear nor consistent path, as it has spanned across geographical areas of concentration, and has had moments of steady progress and pauses along the way. Around 1400 B.C., Egyptian Pharaoh Akhenaton began the worship of a more complex sun deity that included a parsing of the individual rays of sunlight.⁵ In this way of thinking, the light from the sun is seen as life-generative. The Amarna style of Egyptian art represents this idea, where separate rays are isolated with unique qualities in each (Figure 1.2).⁶ Interestingly, this account of sun rays bears some similarities to our current understanding of light, with variation along the electromagnetic spectrum. Although there is evidence that simple optical instruments such as plane and curved mirrors and convex lenses were used by some early civilizations, it is the ancient Greek philosophers who are generally credited with the first secular and pragmatic speculations about the nature of light. The Greeks developed a series of philosophies on light and perception in quick succession, in relative terms. Their research and theoretical development went far beyond properties related to vision, including advancements in mathematics, psychology, and ethics.

From Pythagoras to Anaxagoras, progress was made in the definition of light and dark, as well as an improved understanding of darkness as the absence of light,

Figure 1.2
Solar rays depicted in the Amarna style of Egyptian art, 1370 B.C.

The Amarna art style of Egyptian art, 1370 B.C., depicting the worship of individual rays of sunlight, which is surprisingly consistent with wave theory which breaks light down into wavelengths along a spectrum.

Erich Lessing/Art Resource, NY

rather than as an entity in itself. In the 4th century B.C., Aristotle deeply explored ideas of sensory perception, and he attempted to break down the components of perception into their own respective realms, including the human biological sensory component, the medium through which light traveled, the object being seen, and the process of transmission between each element. He advocated a theory of intromission in which the eye received rays rather than directing them outward. Furthermore, Aristotle proposed a more holistic view of light and the circumstances in which it operates in a more specific and general sense.⁷ The predominant way of understanding the universe at the time was the assumption that the Earth was at the center with the other celestial bodies orbiting around it. The assumption that the Earth is at the center of the orbits of celestial bodies is known as the geocentric model. Aristotle laid the foundations of modern science with his argument that theory should agree with observations. He advocated a geocentric model of the universe composed of concentric spheres centered around the Earth. In his conception, the sun’s sphere was between Venus and Mars. This model was largely accepted even though the Greeks had recorded planetary phenomena with contradictions to this notion, which were unexplained by Aristotle.⁸ Aristotle began to speculate that “vision” goes beyond what is literally seen, and that concepts can be understood, or “seen,” without having been directly witnessed.

Aristotle brought a theory that light and heat and even gravitational forces are disseminated across the spaces between planets, and he therefore needed to account for how this occurred. He suggested that there was a medium that allowed for the transmission of light, and thus was the first to describe physical space in the way we currently understand it. Because the term “spatium” was used for “room” or “interval,” but not as an abstract notion of a void with some mass and particulates, he was incorrect in his postulation that there existed a sort of “fire” emanating from objects within said physical space. Claudius Ptolemy, a Roman citizen of Egypt in the 1st century A.D., sought to improve the Aristotelian model of the universe so that it would better agree with empirical observations by adding extra loops known as epicycles to planetary orbits. Although Ptolemy’s model matched observations better than Aristotle’s, its predictive power was still poor. Nevertheless, it eventually became part of Roman Catholic Church doctrine and was accepted as the dominant view for over 1,500 years. There was then a large gap in time regarding development of vision theories; it was not until the 16th and 17th centuries that humankind’s understanding of light began to progress once again. Thinkers such as Copernicus, Kepler, and Galileo refuted and reconstructed Aristotelian concepts in astronomy, geometry, and thus light—beginning a platform for contemporary scientific thought. Kepler made great strides in optics with his description of how the eye works, explaining how the eye manages the light rays that enter. Kepler’s work brought together geometrical optics and intromission theories of vision, which had been started by Alhazen.⁹

The Heliocentric Perspective

Although the ancient Greek philosopher Aristarchus had proposed such a model over 1,800 years earlier, Nicolaus Copernicus is generally credited with developing the first detailed heliocentric model of the universe. Working in the 16th century, Copernicus threw out several key assumptions held by previous philosophers to devise a much more elegant model describing planetary motion. Most importantly, he put the sun at the center of the orbits of all the planets and explained apparent retrograde motion as the result of planets passing one another in their concentric orbits. Copernicus’s model was a substantial improvement in terms of elegance, but still did not provide strong predictive power because he retained the assumption that planetary orbits were circular.

In the early 17th century, Galileo Galilei made observations using the telescope he invented, which provided strong support for the heliocentric model. He observed moons orbiting Jupiter and phases of Venus relative to the sun that would have been impossible under the Ptolemaic model. The Catholic Church punished Galileo for his views, which were considered to be in opposition to church doctrine, but, as a result of his observations, most astronomers had accepted the heliocentric viewpoint by the end of the 17th century.

It was Johannes Kepler, a contemporary of Galileo, who resolved the mathematics of the heliocentric model with his three laws of planetary motion. Most important among these was the recognition that the orbits of the planets were ellipses rather than circles. Using his model, astronomers could finally predict the locations of celestial bodies with accuracy. Willebrord Snell studied and developed theories involving refraction. Snell’s Law explains the relationship between angles of incidence and refraction, thus bearing his name.¹⁰

Today, we understand our entire solar system to be an insignificant speck in our galaxy and our galaxy one of billions in the universe. Chapter 2 and Chapter 3 and the following will examine solar geometry, the geometry of the sun’s position relative to a point on Earth. A solid working understanding of this material is essential to successful design. Chapter 2 frames the earth–sun relationship from a heliocentric perspective. Because we and our buildings are located on Earth, however, it is more convenient to work from a geocentric perspective in design. Chapter 3 covers the geocentric model useful to designers.

Figure 1.3 Descartes’s Theory of Light and Perception

Diagrammatic representation of Rene Descartes’s scientific research of light perception theory, using geometry and “ether” theory.

Public domain

In the 17th century, Descartes, a French philosopher, developed a new concept of space that related to light perception and ultimately furthered the standing body of knowledge at the time (Figure 1.3). Descartes’s system proposed the use of only matter and motion to explain perception. In the view of Descartes, space was filled with small masses of a material called the “ether” that could transmit f...