Net Zero Energy Building

Predicted and Unintended Consequences

Ming Hu

• Editorial: Routledge
• Año: 2019
• ISBN:
  9781351256506
• Edición: 1
• Categoría: Architecture
• Categoría: Architecture General

What do we mean by net zero energy? Zero operating energy? Zero energy costs? Zero emissions? There is no one answer: approaches to net zero building vary widely across the globe and are influenced by different environmental and cultural contexts.

Net Zero Energy Building: Predicted and Unintended Consequences presents a comprehensive overview of variations in 'net zero' building practices. Drawing on examples from countries such as the United States, United Kingdom, Germany, Japan, Hong Kong, and China, Ming Hu examines diverse approaches to net zero and reveals their intended and unintended consequences.

Existing approaches often focus on operating energy: how to make buildings more efficient by reducing the energy consumed by climate control, lighting, and appliances. Hu goes beyond this by analyzing overall energy consumption and environmental impact across the entire life cycle of a building—ranging from the manufacture of building materials to transportation, renovation, and demolition. Is net zero building still achievable once we look at these factors?

With clear implications for future practice, this is key reading for professionals in building design, architecture, and construction, as well as students on sustainable and green architecture courses.

Chapter 1

The evolution of net zero energy building

Background and ecological origin: ecological economics

The concept of “net energy” has its origin in, as well as a close relationship to, ecology. In 1920, English chemist Frederick Soddy first offered a new perspective on economics rooted in physics: the laws of thermodynamics. Soddy highlighted the importance of energy in social progress based on real wealth formation—as distinct from virtual wealth—and a debt accumulation process.¹ He suggested a detailed accounting structure for energy use as a good alternative to the monetary system. The latter treated economics as a perpetual motion machine; however, as with any commodity, actual wealth flow should obey the laws of thermodynamics.² Soddy argued that real wealth was derived from the use of energy to transform materials into physical goods and services.³ However, his theory was largely criticized and ignored in his time, due to his standing as a critic—not a scholar—of orthodox economics. The contempt was pervasive—in one review of his book Wealth, Virtual Wealth, and Debt, The Times Literary Supplement remarked: “it was sad to see a respected chemist ruin his reputation by writing on a subject about which he was quite ignorant . . . .”⁴ Consequently, the ignorance and criticism of Soddy’s theory contributed to a long-term lack of associated research development between 1920 and 1970 on the concept of energy flow, resulting in stalled progress in energy accounting for a lengthy period.

During the above-mentioned gap, there was one notable development: the Technical Alliance, a professional group of architects, engineers, economists, and ecologists that was formed in 1919 before later disbanding in 1921. The group started the Energy Survey of North America with the aim of documenting the wastefulness of the entire society, marking the first attempt to quantify net energy.² The ensuing silence during the following 50 years set the stage for the blossoming of new concepts and ideas that would emerge in the 1970s.

In the 1970s, Romanian-American mathematician and economist Nicholas Georgescu-Roegen further developed ecological economics, or eco-economics, based on Soddy’s concepts. Eco-economics is a transdisciplinary and interdisciplinary field of research that includes ecology, economics, and physics. Georgescu-Roegen proposed the application of the entropy law in the field of economics, where he argued that all natural resource consumption is essentially irreversible, which has a profound impact on the net energy flow or life cycle thinking of natural resources. He was the first economist of some standing to put forward theories on the premise that all of Earth’s mineral resources would eventually be exhausted at some point,⁵ and this concept of natural resource depletion eventually led to a movement of sustainable development. As he stated, “An unorthodox economist—such as myself—would say that what goes into the economic process represents valuable natural resources, and what is thrown out of it is valueless waste.”⁶ To some extent, we can consider Nicholas Georgescu-Roegen as the original gardener who planted the seeds of sustainable development in our society.

Another important development in the 1970s was the publication of the article “Energy, ecology, and economics” and the book Environment, Power and Society by ecologist Howard Odum, who tackled economic issues using ecological theories based on energy fundamentals. His energy economics were based on the comprehension that energy is the foundation for all forms of life and is transformable. He stated that “the true value of energy to society is the net energy, which is that after the costs of getting and concentrating that energy are subtracted.”⁷ Odum’s view of studying ecology as a large and integrative ecosystem paved the way to an understanding of how different aspects of a whole ecosystem influence each other. In the latter part of his career, he developed a concept of energy in the 1990s, called Emergy. Odum explained that energy provides for real work and real wealth in any biophysical system, including the economy, in his 1996 publication, Environmental Accounting: Emergy and Environmental Decision Making.⁸ He stated:

Understanding the economy requires that both money circulation and the pathways of real wealth be represented together but separately. Money is only paid to people and never to the environment for its work . . . Therefore, money and market values cannot be used to evaluate the real wealth from the environment. When the resources from the environment are abundant, little work is required from the economy.”⁸

Emergy has since attracted the attention of academic researchers and is being applied beyond just the natural ecosystem, to research in the building and construction industry.^{9, 10}

1930–1969: early solar house

Some of the first documented attempts toward energy-efficient buildings were merged as an effort to achieve net zero heating and cooling in solar houses, which originated around the 1930s. One of the earliest pioneer buildings was the 1939 MIT Solar House I, which introduced the use of a large solar thermal collector and water storage in houses.¹¹ Additionally, the solar air collector and rock mass storage used in Bliss House have become two of the most applied solar technologies still in use today. In September 1936, the dean of the MIT School of Engineering, Vannevar Bush—a renowned American inventor, engineer, and early administrator of the Manhattan Projectⁱ—began to pursue research in solar energy, and his idea of flat sun collectors impressed Boston-based philanthropist Godfrey L. Cabot. Cabot donated nearly $650,000 to MIT in 1938 and instructed that the fund be used specifically “in development of the art of converting the energy of the sun to the use of man by mechanical, electrical, or chemical means.” Consequently, the fund stimulated the formation of MIT’s Solar Energy Fund. Dr. Maria Telkes was the first hire by Vannevar Bush using the solar fund. Dr. Telkes’s expertise and knowledge as a physical chemist and biophysicist enabled her research on a thermoelectric device that could convert heat directly into electrical energy. This technology was very different from those used in other solar houses within the same MIT Solar Energy Research Project. During the 50 years that the Solar Energy Project lasted (1938–1988), a series of six experimental prototype solar houses were built.¹² Among them, only Dover Sun House was built using Dr. Telkes’s technology instead of popular methods that used water as a heat storage material. Her device used sodium sulfate decahydrate (Glauber’s salt) as a storage material. The sun heat collector was composed of two layers of flat glass filled with air in between and a layer of black sheet metal completely covering the second layer of the glass panel, and these collectors and panels covered the entire south-facing façade of the house. The primary experimental and research objective of using the salt was to test the relative effectiveness of a chemical heat-of-fusion process, instead of conventional hot-water heat storage devices,¹³ with the hope of such technology eventually increasing the efficiency of solar energy conversion and making it more affordable and amenable when integrated into all types of building construction. During the daytime, hot air was circulated in the drums where the salts were stored. The salts contained crystals that were bound to water molecules; the crystals would melt at high temperatures while absorbing the heat. The heat would then be stored in a liquid form of the crystals. During the night, when the temperature dropped, the compound made of salt and water would recrystallize, releasing the heat.⁵ Interestingly, this technology could essentially be viewed as the predecessor of current phase-changing material technology (see Chapter 6 for more details).

1970–1989: first energy crisis and the emergence of net zero energy building

The first wave of energy crises, in the 1970s, sparked an energy efficiency movement. On October 17, 1973, six Arab and non-Arab members of the Organization of the Petroleum Exporting Countries decided to raise the price of oil exports by 70%. On the same day, nine Arab oil-producing countries imposed an embargo on oil supplies to the United States and the Netherlands in response to the outbreak of the Yom Kippur War.¹⁴ The consequences of the two dramatic actions were devastating to the United States and the Netherlands, but also had a global impact. At that time, scientists and engineers from various fields, including physicists and chemists, started to pay more attention to energy consumption patterns. In particular, Dr. Arthur Rosenfeld,¹⁵ the “godfather of energy efficiency,” observed that the United States consumed about twice the energy per capita as its European counterparts, yet all had comparable standards of living.¹⁶ This proved two facts: first, energy could be conserved through user behavior—such as turning off lights in unoccupied rooms—and second, higher energy consumption did not translate into faster economic development or a higher living standard. He asserted that if Americans used energy at the same rate as Europeans or the Japanese, the United States could have begun exporting oil in 1973. Dr. Rosenfeld met up with colleagues from the Princeton Center for Energy and Environmental Studies and Professor Robert Socolow and Professor Sam Berman from Stanford University...