Zero Energy Architecture-2

Zero Energy Architecture

School of Architecture & Landscape Design, S.M.V.D.U. Avjeet S. Plaha, 2006 EAL 02

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CHAPTER 1

1.1 INTRODUCTION Zero – Energy Architecture can be termed as a practice that exemplifies energy usage at optimum needs and also serves as a flag-bearer for ―off the grid‖ energy production practices. The usage of such a practice in the modern world is a big boost for the human populace as it deals in curbing the energy crisis being faced by the globe, but at the same time providing enough energy so that the living environment is not disturbed, and also to help in cutting down the levels of green-house-gas emissions to a very minute level. With the theme of creating buildings that consume and produce the same amount of energy in a year & that in huge numbers is quite an eye-opening concept and a formidable proposition for the current global energy consumption scene and for developers. Hence, it won‘t be long enough that the ZERO ENERGY BUILDING concept finds a permanent foothold in the building industry which it is currently gaining on.

Through an extensive study of existing zero energy buildings and technologies, this research elaborates on the essence to zero-energy building design. It has been shown by the study of various examples that varied approaches to zero-energy architecture may lead to different outcomes in terms of overall sustainability or regenerative potential.

Fig.1.11:Masdar Headquarters Building, Masdar City, U.A.E – a zero emission building



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1.2 SCOPE

In the pages that follow, an endeavor has been made to emphasize upon the ideology of designing a zero-energy building or inculcating the practice of zero-energy architecture as a solution to increasing urban concerns with clearly indicating various definitions, techniques and examples.

1.3 OBJECTIVES

To get a picture of the global energy consumption and energy emissions

scenario with a specific reference to the energy consumption and green house gas emissions for buildings

To comprehend what the term zero-energy architecture/building means and relate it with terms like energy-plus building and ultra-low energy building.

To understand and compare the various definitions of zero-energy architecture with respect to site energy, source energy, energy costs & energy emissions.

To highlight in brief the theme of energy harvest and energy consumption.

To recognize and highlight the role of organizations dealing in the promotion of this ideology like ―Architecture 2030‖.

To discuss the association of the term zero-energy architecture with green architecture and sustainable architecture.

To discuss in depth the design techniques used to make a zero-energy building supplemented with relevant case studies.

To evolve a conclusion that signifies the relevance of the ―zero-energy‖ theory in the modern urban context.

1.4 METHODOLOGY

For the purpose of this document, the data, by means of internet and library, has

been collected for the following topics of discussion:- - Energy consumption as well GHG emissions for the building industry. - Varied definitions evolved for zero energy buildings. - Zero-energy architecture – green architecture - Techniques to make a zero-energy building or a net zero-energy building

or to regulate the energy consumption of a building. - Overall energy regulation data for buildings by means of examples of

existing buildings or of proposed buildings. - The significance of the concept in the current scenario with relation to

climatic changes as well the mounting urbanization.



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CHAPTER 2

2.1 Energy Consumption by The Building Sector

The construction industry is one of the globe‘s most important economic sector. More than US $3 trillion are expended annually in the world, which is equal to 1/10th of the global economy and as far as construction businesses are concerned, it constitutes 30% of the businesses in Europe, 22% of the businesses in USA, 21% in Japan and 23% in the developing countries. Buildings have a significant impact on energy use and the environment. Globally speaking on an average, the construction and building sector uses almost 40% of the primary energy and approximately 70% of the electricity produced globally with the commercial buildings contributing to this percentage in amounts more than half that is contributed by the residential sector. The WBCSD (World Business Council for Sustainable Development) identified buildings as one of the five main users of energy where ―mega trends‖ are needed to transform energy efficiency. The International Energy Agency (IEA) estimates that current trends in energy demand for buildings will stimulate about half of energy supply investments to 2030. The energy used by the building sector continues to increase primarily because new buildings are constructed faster than old ones are retired. It was observed that electricity consumption in the commercial building sector doubled between 1980 and 2000, and is expected to increase another 50% by 2025 (EIA 2005). Energy consumption in the commercial building sector will continue to increase until buildings can be designed to produce enough energy to offset the growing energy demand of these buildings. One significant fact that accompanies the usage of the conventional resources of energy to supply our energy requirements is their contribution to the green house gas (GHG) emissions, leading to the commonly observed phenomenon of global warming. With so much attention being given to transportation emissions, many people are surprised to learn that buildings are the single largest contributor to global warming. For instance, Data from the US Energy Information Administration illustrates that buildings are responsible for almost half (48%) of all energy consumption and GHG emissions annually. Seventy-six percent (76%) of all power plant generated electricity is used just to operate buildings. Furthermore, the annual building construction and materials embodied energy estimate for residential buildings sector, the commercial building sector and the industrial buildings sector was computed. It was found that the total annual 2000 Building Sector consumption was 48.17 QBtu and the total annual 2000 US Energy consumption was 99.38 QBtu , more than 50%.



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The annual embodied energy of building materials and the energy used to construct buildings is estimated at 1.146 MBtu/sf of building for new construction and half of this for renovation. At the current rate of construction in the US of approx. 5 Bsf of new building and 5 Bsf of renovation (EIA and Dodge), the total annual energy consumed is

approx. 8.6 QBtu, or 8.6% of the total US annual energy consumption. [1]

Fig.2.11: The Building Sector Charts , source:- US Energy R&D administration

2.2 An Energy Study – India , China [2]

If building site energy consumption in China and India grows to current US levels, China‘s and India's consumption will be respectively about four and seven times greater than they are today. Figure 2.21 shows a projection based on current population forecasts combined with current energy use per capita based on Japanese and US levels – what could be considered the best and worst case scenarios. This highlights the fact that energy consumption will grow dramatically regardless of any action to improve energy efficiency substantially. The construction boom, especially in China, is increasing energy demand significantly, but economic development and other factors are adding to the challenge because they also increase buildings‘ energy needs.

Fig.2.21: Best & Worst case projections for site energy demands

[1] http://www.Architecture2030.com/Why

[2] “Energy Efficiency in Buildings: Business realities and opportunities”, WBCSD

http://www.architecture2030.com/Why



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The scale of current property stock in several countries or regions, broken down into commercial and residential occupancy, is shown in Figure 2.22. The property market in China is particularly notable and is growing rapidly; China is adding 2 billion square meters a year, equivalent to one-third of Japan's existing building area. This means China is building the equivalent of Japan's building area every three years.

Fig.2.22: Existing Building Floor Space

There are large differences in space per person between regions (see Figure 2.23), especially the much greater residential space per capita in the US. The differences are less marked in commercial buildings, except for China, which currently uses much less

commercial space per capita than other regions. This has significant implications for energy use, assuming that space demands in China move toward those in Europe and Japan, if not the US.

Energy use for buildings in the US is substantially higher than in the other regions, and this is likely to continue (see Figure 2.24). Consumption in China and India will grow rapidly, however, and China‘s building energy consumption will

Fig.2.23: Building Floor Space per Person

be approaching Europe‘s by 2030, while

India will have overtaken Japan. If current trends continue, commercial building energy use in China will more than double during this period. Energy consumption in Western Europe will rise only moderately and will remain flat in Japan. Building energy in Brazil will grow, but will remain relatively small in 2030 compared with other regions. Focusing on the energy demands of buildings (site energy), the sources of energy vary greatly (see Figure 2.25), with a significant amount of coal and biomass burned on site in China and India, but with a much higher share of electricity being used in other countries. This variation contributes to large differences in primary energy consumption (see Figure 2.26) because of the additional energy demands of power generation and distribution. Development and urbanization are associated with increased electricity use, which will significantly increase primary energy demand in China and India. Figure 6 also emphasizes the scale of primary energy demand by US commercial space.



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Fig.2.24: Building Energy Projection by Region

Fig.2.25: Site Energy Sources

Fig.2.26: Primary Energy (2003)

More than four-fifths of site energy use typically occurs in the operational phase of a building‘s life, as Figure 2.27 shows. The proportion of energy embodied in materials and construction will rise if operational energy efficiency increases and if building life spans shorten.



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Fig.2.26: Life Cycle Energy Use

2.3 Green House Gas (GHG) emissions from the building sector

GHG are released in the atmosphere during each stage of buildings life[3]

:

- Building construction - Building operation - Building renovation and deconstruction

Building Construction: [4]

GHG emissions associated with buildings construction are mainly coming from: - Materials manufacturing (e.g., concrete) - Materials transport - Demolition wastes transport - Demolition wastes treatment The construction, renovation, and deconstruction of a typical building are on average responsible for the emissions of 1,000-1,500 kg CO2e/m2 (around 500 kg CO2e/m2 for construction only).

Operation: [4]

GHG emissions associated with buildings operation are mainly coming from: 1-Electricity consumption 2-Consumption of fossil fuels on-site for the production of electricity, hot water, heat etc. 3-On-site waste water treatment 4-On-site solid wastes treatment 5-Industrial processes housed in the buildings [3] THE BUILDING SECTOR AND GREENHOUSE: KEY FACTS

[4] U.S. Greenhouse Gas Inventory Report, 2009



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Depending on the region where the building is located and the building energy mix, operation emissions can vary from 0 to over 100 kgCO2 e/m2 per year. Institutional buildings account for about one-third of the primary global energy demand.

They represent a major source of energy-related GHG emissions. [5]

In the U.S. for instance, emissions from buildings, including those emissions from both fuel combustion and use of electricity derived from CO2 emitting sources, account for nearly 37 % of total U.S. CO2 emissions (electricity accounts for about 45 % of energy use in U.S. buildings and about 70 % of the electricity

generated is consumed in buildings). [5]

There were 83 million buildings having a total floor space of almost 15 billion m2 in the U.S. in 2000. Annual new construction is about 1-3 %. The relatively slow growth in new construction means that much of the opportunity in the U.S. for energy efficiency comes

through retrofits. This is not true of other countries. [5]

Economic growth in the developing nations will drive dramatic increases in their building construction. It is estimated that fully 50% of all new buildings will be constructed in China and India. China alone is adding over 2 billion m2 / year. At this rate, in the next decade China will construct new buildings having a floor space equivalent to all of the

current U.S. building stock. [5]

Typically, over 80% of the life cycle energy use is associated with operation of the building rather than construction or renovation (including material manufacturing and transport).

2.4 The move towards energy efficiency and zero energy As the construction scene is booming, the absolute figure regarding energy consumption continues to rise quickly especially in countries like India and China. It is essential to act now, because buildings can make a major contribution to tackling climate change and energy use. Progress can begin immediately because knowledge and technology exist today to slash the energy buildings use, while at the same time improving levels of comfort. Behavioral, organizational and financial barriers stand in the way of immediate action, and three approaches can help overcome them: • Encourage interdependence by adopting holistic, integrated approaches among the stakeholders that assure a shared responsibility and accountability toward improved

energy performance in buildings and their communities [6]

[5] US Energy Research and Development Administration

[6] “Energy Efficiency in Buildings: Business realities and opportunities”, WBCSD



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• Make energy more valued by those involved in the development, operation and use of

buildings [7]

• Transform behavior by educating and motivating the professionals involved in building

transactions to alter their course toward improved energy efficiency in buildings. [7]

The drive towards energy efficient and net-zero energy buildings is the latest phase in the ongoing process of raising the bar on sustain-ably designed buildings. Since the 1990‘s the LEED rating system has increased the adoption of green building technologies and spurred competition to reach sustainable building goals. However many LEED-certified buildings did not improve energy efficiency beyond code allowances. Nowadays, a number of architecture firms and organizations are striving for the ambitious goal of creating zero-energy buildings that fully offset their energy consumption and carbon emissions by generating electricity and/or heat onsite using renewable resources. A number of factors, some which are under the possible control of human beings as well as some that are not in control of the human beings, contribute towards this re-thinking or re-inventing process. The devastation that accompanies natural calamities like typhoons, hurricanes (hurricane ―Katrina‖ for instance), evidences about the melting polar ice cap have increased the concern regarding the rapid global climate change. This was demonstrated in ―An Inconvenient Truth‖, an eye-opening documentary by Al

Gore regarding the climate change and the mounting concern about global warming. [8]

The documentary lead to or rather initiated a change in the numerous energy policies in the United States to transform its electrical grid to rely solely on renewable energy sources within a decade and change its tax policies to encourage use of renewable

sources of energy. [8]

As per the WBCSD‘s ―Energy Efficiency in Buildings‖ (EEB) project [9]

, the new world

vision is that of buildings that consume net zero energy, and working with an ambition to address climate change and energy use. End uses vary by sector, region and climate. For example, refrigeration is a major user of energy in food retailing, while non-food retail uses substantially more energy for lighting than other sectors do. Food service and food sales are high-intensity sub-sectors, but the large amount of office space means this is likely to be the greatest overall energy user. Energy use varies among residential buildings, but space and water heating are substantial components in most regions.

[7],[9] “Energy Efficiency in Buildings: Business realities and opportunities”, WBCSD

[8] “centerline”, newsletter of the Center for the Built Environment, University of California, Berkeley, Summer 2008



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Dramatic improvements in the energy performance of buildings can reduce greenhouse gas (GHG) emissions more quickly and more cost-effectively than many other options – while helping reduce the impact of rising and increasingly volatile energy prices. Many stakeholders, including industry and professional associations; voluntary high-performance building organizations; codes and standards organizations; and many leading utilities, state and local agencies, and private building designers, developers, owners and operators, and equipment manufacturers have all recognized the need for

more aggressive and effective action. [10]

Transforming energy performance in commercial buildings requires a comprehensive and concerted industry effort, sufficient in scale to influence the more than $500B per year that the sector spends on new construction, renovation and energy. [10] “Energy Efficiency in Buildings: Business realities and opportunities”, WBCSD



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CHAPTER 3

3.1 Zero –Energy Architecture :: What is it??

With the mounting concern raised by global warming, architectural organizations and firms have adopted many new design practices keen to impede the growing stockpile of environmental problems that the buildings are adding on to and concurrently do not substantially alter the standard of living conditions to which we are so familiar with. Some of these practices/solutions heavily involve the optimal usage of energy by the building, principally emphasizing the usage of renewable sources of energy as prime energy generation sources; using the features of the site such as bio-climatic conditions, wind direction, sun paths etc and the inclusion of certain measures that can regulate the energy utilization for a building like fenestration material and control, use of shading devices to regulate the entry of sunlight etc. Of the typical practices that are applied in the current design processes are green architecture, sustainable architecture, energy –efficient architecture and a new and not so-old practice – zero - energy architecture.

For anyone who hears the term zero-energy architecture or zero-energy building or event the term zero energy, he/she‘s foremost interpretation of the term would be an edifice that operates on no energy at all. Imagine, a building running on no energy, wouldn‘t that be a sight to see! But the fact remains that the only building or structure or edifice ever to be built that uses no energy is……. a cave (figure 3.11), and taking into consideration the luxury

Fig.3.11: The Cave – earliest form of a Zero-energy building

Source: National Geographic

or the standard of living conditions that people have grown accustomed to, no one would be too enthusiastic to go back to the stone-age life-style. So the question remains, what is a zero-energy building?? Before going further, let‘s just clear one question of skepticism. The term zero in reality refers to ―net-zero‖, meaning, the amount of energy consumed is also produced and it implies no zero flows. So a zero-energy building will be any structure be it residential or commercial that operates on greatly reduced needs of energy by means of efficiency gains such that the balance of the energy needs



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can be supplied by renewable technologies.

It can further refer to a building's use

with zero net energy consumption and zero carbon emissions annually or in short a zero energy building will be a structure with highly reduced energy needs such that the amount of energy it consumes in a year is also produced by the building in the span of one year accompanied

by zero carbon emissions. [11]

Fig.3.12: Marin Country Day School – a Zero Energy Building

Zero energy buildings or ZEB‘s can be used autonomously from the energy grid supply

– energy can be harvested on-site. [12]

The net zero design principle is overlaid on the

requested comfort of the building occupant. Generally, the more extreme the exposure to the elements the more energy is needed to achieve a comfortable environment of human use.

3.2 Modern Evolution Driven on by the extensive use of fossil energy, zero energy buildings are being regarded as the prime solution to zero fossil energy consumption and as a promoter of renewable energy harvesting to cut down on the green-house gas emissions The development of modern zero-energy buildings became possible not only through the progress made in new construction technologies and techniques, but it has also been significantly improved by academic research on traditional and experimental buildings, which collected precise energy performance data. Today's advanced

computer models can show the efficacy of engineering design decisions. [12]

Energy use can be measured in different ways (relating to cost, energy, or carbon emissions) and, irrespective of the definition used, different views are taken on the relative importance of energy harvest and energy conservation to achieve a net energy balance. Although zero energy buildings remain uncommon in developed countries, they are gaining in importance and popularity. Most ZEB definitions do not include the emissions generated in the construction of the building and the embodied energy of the structure. So much energy is used in the construction of a new building that this can dwarf the operational energy savings over its

useful life. [13]

[11] http://www.zeroenergycbc.org

[12] http://en.wikipedia.org/wiki/Zero-energy buildings

[13] “centerline”, newsletter of the Center for the Built Environment, University of California, Berkeley, Summer 2008

http://en.wikipedia.org/wiki/Building

http://en.wikipedia.org/wiki/Developed_country

http://en.wikipedia.org/wiki/Zero-energy



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Using ZEB design goals takes us out of designing low-energy buildings with a percent energy savings goal and into the realm of a sustainable energy endpoint. The goals that are set and how those goals are defined are critical to the design process. The definition of the goal will influence designers who strive to meet it (Deru and Torcellini 2004). Because design goals are so important to achieving high-performance buildings, the way a ZEB goal is defined is crucial to understanding the combination of applicable

efficiency measures and renewable energy supply options. [14]

A building approaching net zero-energy use may be called a near-zero energy building or ultra-low energy building. Buildings that produce a surplus of energy during a

portion of the year may be known as energy-plus buildings. [15]

3.3 The Energy-Plus Movement[15]

Another movement that accompanies the zero-energy movement is the positive-energy or energy plus buildings consisting of buildings that work on the essential principle of zero energy buildings but they produce a significantly higher amount of energy than they consume, thus enabling them to be called as mini- transformer units.

Some of their features of this movement include [16]

:-

- a very high energy efficiency - highly intensified use of renewable sources for energy

production - production of more energy than consumption

Certain elements that will be a key element behind this movement

are [16]

:-

- Reduction of transmission losses Fig.3.31: Pearl Tower

- Reduction of ventilation losses an energy plus building

- Increase of solar gains - Increased efficiency of heat and cold generation - Increased daylight availability and efficiency of luminaires - Measures for avoiding air conditioning - Consideration of the life cycle analysis and adequate business ideas

Though this concept is still yet to stretch its wings in the real-world scene but in theory it sounds like a highly cost effective solution for any locality to meet its any energy shortages by using the surplus energy from the buildings around it instead of importing from an external grid supply. [14] “centerline”, newsletter of the Center for the Built Environment, University of California, Berkeley, Summer 2008


[16] Prof. Dr. Gerd Hauser “Neutral/ Energy Positive Buildings”, April 13, 2010

http://en.wikipedia.org/wiki/Low_energy_house

http://en.wikipedia.org/wiki/Energy-plus-house




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CHAPTER 4

4.1 Defining a Zero Energy Building When energy goals are set as percent savings, an energy scale is implied. The question of ―savings from what?‖ is often asked. Zero is the crossover point between a building that consumes a resource and one that produces the resource. Conceptually, it is envisioned as the point where the energy needs of the building has no impact. A zero energy building can be defined in several ways, depending on the boundary definition and the quantum of energy flow. Different definitions may be appropriate, depending on the project goals and the values of the design team and building owner. For example, building owners typically care about energy costs. Organizations such as DOE are concerned with national energy numbers, and are typically interested in

primary or source energy. [17]

A building designer may be interested in site energy use

for energy code requirements. Finally, those who are concerned about pollution from power plants and the burning of fossil fuels may be interested in reducing emissions. The zero energy definition affects how buildings are designed to achieve the goal. It can emphasize energy efficiency, supply-side strategies, purchased energy sources, utility rate structures, or whether fuel-switching and conversion accounting can help meet the goal. The following concepts and assumptions have been established to help guide

definitions for ZEBs [17]

:-

1. Grid Connection Is Allowed and Necessary for Energy Balances [17]

A ZEB typically uses traditional energy sources such as the electric and natural gas utilities when on-site generation does not meet the loads. When the on-site generation is greater than the building‘s loads, excess electricity is exported to the utility grid. By using the grid to account for the energy balance, excess production can offset later energy use. Achieving a ZEB without the grid would be very difficult, as the current generation of storage technologies is limited. Despite the electric energy independence of off-grid buildings, they usually rely on outside energy sources such as propane (and other fuels) for cooking, space heating, water heating, and backup generators. [17] P. Torcellini, S. Pless, M. Deru, D. Crawley. “Zero Energy Buildings: A Critical Look at the Definition”. National

Renewable Energy Laboratory (NREL), June 2006



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2. Prioritize Supply-Side Technologies to Those Available On Site and within

the Footprint [18]

Various supply-side renewable energy technologies are available for ZEBs. Typical examples of technologies available today include PV, solar hot water, wind, hydroelectric, and bio-fuels. All these renewable sources are favorable over conventional energy sources such as coal and natural gas; however, experts have developed a ranking of renewable energy sources in the ZEB context. Table 4.1

shows this ranking in order of preferred application. The principles [18]

that have been

applied to develop this ranking are based on technologies that:

• Minimize overall environmental impact by encouraging energy-efficient building designs and reducing transportation and conversion losses.

• Will be available over the lifetime of the building. • Are widely available and have high replication potential for future ZEBs.

Option Number

ZEB Supply-Side Options

Examples

1. Reduce site energy use through low-energy building

technologies Day-lighting, high-efficiency HVAC

equipment, natural ventilation,

evaporative cooling, etc.

On-Site Supply Options

2. Use renewable energy sources available within the

building’s footprint PV, solar hot water, and wind located

on the building. 3. Use renewable energy sources available at the site PV, solar hot water, low-impact

hydro, and wind located on-site, but

not on the building. Off-Site Supply Options

4. Use renewable energy sources available off site to

generate energy on site Biomass, wood pellets, ethanol, or

bio diesel that can be imported from

off site, or waste streams from on-site

processes that can be used on-site to

generate electricity and heat.

5. Purchase off-site renewable energy sources Utility-based wind, PV, emissions

credits, or other “green” purchasing

options. Hydroelectric is sometimes

considered.

Table 4.1: ZEB Renewable Energy Supply Option Hierarchy

This hierarchy is weighted toward renewable technologies that are available within the building footprint and at the site. Rooftop PV and solar water heating are the most applicable supply-side technologies for widespread application of ZEBs. Other supply-side technologies such as parking lot-based wind or PV systems may be available for limited applications. Renewable energy resources from outside the boundary of the building site could arguably also be used to achieve a ZEB. [18] P. Torcellini, S. Pless, M. Deru, D. Crawley. “Zero Energy Buildings: A Critical Look at the Definition”. National




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This approach may achieve a building with net zero energy consumption, but it is not the same as one that generates the energy on site and should be classified as such. Hence for a building of such a nature is termed as an ―off-site ZEB‖ as it uses renewable energy from sources outside the boundaries of the building site.

4.2 The types of Zero Energy Building definitions [19]

Four commonly used definitions are: 1. Net Zero Site Energy Building 2. Net Zero Source Energy Building 3. Net Zero Energy Costs Building 4. Net Zero Energy Emissions Building

- Net Zero Site Energy Building

A net zero site energy building produces as much energy as it uses when measured at the site. This definition as a goal is useful, as it can be verified through on-site metering. It tends to encourage energy-efficient designs. However, it does not distinguish between fuel types or account for inefficiencies in the utility grid. The site must also be defined. Is the site just the building footprint, or does it include the entire property? What happens if you cover a parking lot with photovoltaic (PV) panels to achieve your zero energy building, only to develop that space later into a new building? This would give higher priority to PV systems that are within the building footprint because it is always part of

the building. [19]

- Net Zero Source Energy Building A net zero source energy building produces as much energy as it uses compared to the energy content at the energy source. The system boundary is drawn around the building, the transmission system, the power plant, and the energy required getting the fuel source to the power plant. It tends to be a better representation of the total energy impact. However, it is challenged by difficulties in acquiring site-to-source conversions and by the limitations of these conversions. Fixed conversion factors do not account for dispatch of energy with time of day, and the changes in dispatch as new buildings and the new power plants to supply them come on-line. [19] P. Torcellini, S. Pless, M. Deru, D. Crawley. “Zero Energy Buildings: A Critical Look at the Definition”. National




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This definition can depend on how the utility is buying or producing the power, rather than on the energy performance of the building. So, if someone wants to construct a building in an area with a large percentage of hydroelectric energy, it may have a low source energy impact. However, placing the building in that location may necessitate new fossil fuel generation plants and the building may actually use the new generation

capacity, which is coal. This analysis is very difficult. [20]

- Net Zero Energy Cost Building

Building owners are typically most interested in net zero energy cost buildings, and tend to use energy efficiency and renewable energy as part of their business plans. This definition, like the site ZEB definition, is easy to verify with the utility bills. Market forces provide a good balance between fuel types based on fuel availability. Costs also tend to include the impact of the infrastructure. Reaching zero may be difficult or impossible because of utility rate structures. Many rate structures will give credit for energy returned to the grid, but will not allow this number to go below zero on an annual basis. As a result, no way exists to recover costs incurred by fixed and demand charges. Finally, imagine a day when all buildings approach zero energy. Utility rates will need to

be changed to maintain a reliable utility grid. [20]

- Net Zero Energy Emissions Building

A net zero emissions building, looks at the emissions that were produced by the energy needs of the building. This is probably a better model for sustainable energy

sources. However, like the source ZEB definition, it can be difficult to calculate. [20]

People often use definitions to meet their own needs but it is ultimately the design team that must determine, as part of the goal setting process, which definition is being used. Each definition uses the grid for net use accounting and has different applicable renewable energy sources. The definitions do apply for grid independent structures. In support of DOE‘s ZEB research needs, the above listed definitions refer to ZEBs that

use supply-side options available on site. [20]

For ZEBs that have a portion of the renewable generation supplied by off-site sources, these buildings are referred to as ―off-site ZEBs.‖ Off-site ZEBs can be achieved by purchasing renewable energy from off-site sources, or in the case of an off-site zero emissions building, purchasing emissions credits. A table on the following page summarizes all aspects of the 4 types of definitions. [20] P. Torcellini, S. Pless, M. Deru, D. Crawley. “Zero Energy Buildings: A Critical Look at the Definition”. National




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Definition Positives Negatives Other Issues

Site ZEB

• Easy to implement.

• Verifiable through on-site

measurements.

• Conservative approach to

achieving ZEB.

• No externalities affect

performance, can track

success over time.

• Easy for the building

community to understand and

communicate.

• Encourages energy-efficient

building designs.

•Requires more PV export to

offset natural gas.

• Does not consider all utility

costs (can have a low load

factor).

• Not able to equate fuel

types.

• Does not account for non

energy differences between

fuel types (supply

availability, pollution).

Source ZEB

•Able to equate energy value

of fuel types used at the site.

• Better model for impact on

national energy system.

• Easier ZEB to reach.

• Does not account for non

energy differences between

fuel types (supply

availability, pollution).

• Source calculations too

broad (do not account for

regional or daily variations in

electricity generation heat

rates).

• Source energy use

accounting and fuel

switching can have a larger

impact than efficiency

technologies.

• Does not consider all

energy costs (can have a low

load factor).

•Need to develop

site-to-source

conversion factors,

which require

significant amounts

of information to

define.

Cost ZEB

•Easy to implement and

measure.

• Market forces result in a

good balance between fuel

types.

• Allows for demand-

responsive control.

• Verifiable from utility bills.

•May not reflect impact to

national grid for demand, as

extra PV generation can be

more valuable for reducing

demand with on-site storage

than exporting to the grid.

• Requires net-metering

agreements such that

exported electricity can offset

energy and non- energy

charges.

• Highly volatile energy rates

make for difficult tracking

over time.

• Offsetting

monthly service

and infrastructure

charges require

going beyond ZEB.

• Net metering is

not well

established, often

with capacity limits

and at buyback

rates lower than

retail rates.

Emissions ZEB

• Better model for green

power.

• Accounts for non energy

differences between fuel types

(pollution, greenhouse gases). • Easier ZEB to reach.

•Need

appropriate

emission factors.

Table 4.2: ZEB Definitions Summary



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The table highlights the key-notes and aspects of these ZEB definitions by means of a study (Torcellini et al. 2004; Barley et al. 2005) of seven commercial buildings that were designed to impede energy consumption and environmental impacts using a combination of low energy and renewable energy technologies and these serve as an important step towards reaching the ZEB goal and also as a guide to facilitate the commercial side of a ZEB.



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CHAPTER 5

5.1 Energy Harvest[21]

ZEBs harvest available energy to meet their electricity and heating or cooling needs. In the case of individual houses, various micro-generation technologies may be used to provide heat and electricity to the building, using solar cells or wind turbines for electricity, and bio-fuels or solar collectors linked to seasonal thermal stores for space heating. To cope with fluctuations in demand, zero energy buildings are frequently connected to the electricity grid, export electricity to the grid when there is a surplus, and drawing electricity when not enough electricity is being produced. Other buildings may be fully autonomous. Energy harvesting is most often more effective (in cost and resource utilization) when done on a local but combined scale, for example, a group of houses, co-housing, local district, village, etc. rather than an individual basis, an example being the BedZED development in the U.K. An energy benefit of such localized energy harvesting is the virtual elimination of electrical transmission and

electricity distribution losses. These losses amount Fig.5.11: The BedZED Development, a

to about 7.2%-7.4% of the energy transferred.

zero energy neighborhood

Energy harvesting in commercial and industrial applications is chiefly benefited from the topography of each location. The production of goods under net zero fossil energy consumption requires locations of geothermal, micro-hydro, solar, and wind resources to sustain the concept. The ZEB technologies are getting an immense support from the energy harvest phenomenon in establishing cities that are totally off the electricity supply grid, i.e. : net zero energy use cities, with their districts functioning by means of distributed energy generation schemes which, in some cases, may include district heating, community chilled water, shared wind turbines, etc. [21] http://en.wikipedia.org/wiki/Zero-energy buildings

http://en.wikipedia.org/wiki/Microgeneration

http://en.wikipedia.org/wiki/Solar_cell

http://en.wikipedia.org/wiki/Wind_turbine

http://en.wikipedia.org/wiki/Biofuel

http://en.wikipedia.org/wiki/Solar_collector

http://en.wikipedia.org/wiki/Seasonal_thermal_store

http://en.wikipedia.org/wiki/Electricity_grid

http://en.wikipedia.org/wiki/Electrical_transmission

http://en.wikipedia.org/wiki/Electricity_distribution

http://en.wikipedia.org/wiki/Commerce

http://en.wikipedia.org/wiki/Industry

http://en.wikipedia.org/wiki/Topography

http://en.wikipedia.org/wiki/Geothermal_power

http://en.wikipedia.org/wiki/Microhydro

http://en.wikipedia.org/wiki/Solar_energy

http://en.wikipedia.org/wiki/Wind

http://en.wikipedia.org/wiki/Distributed_generation

http://en.wikipedia.org/wiki/Distributed_generation

http://en.wikipedia.org/wiki/District_heating




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5.2 Energy Harvest VS Energy Consumption[22]

One of the key areas of debate in zero energy building design is over the balance between energy conservation and the distributed point-of-use harvesting of renewable energy (solar energy and wind energy). Most zero energy homes use a combination of the two strategies. As a result of significant government subsidies for photovoltaic solar electric systems, wind turbines, etc., there are those who suggest that a ZEB is a conventional house with distributed renewable energy harvesting technologies. Entire additions of such homes have appeared in locations where photovoltaic (PV) subsidies are significant, but many so called "Zero Energy Homes" still have utility bills. This type of energy harvesting without added energy conservation may not be cost effective with the current price of electricity generated with photovoltaic equipment (depending on the local price of power company electricity), and may also require greater embodied energy and greater resources, thus it will be the less ecological approach.

Since the 1980s, passive solar building design and passive house have demonstrated heating energy consumption reductions of 70% to 90% in

Fig.5.21: A Passive House

many locations, without active energy harvesting. For new builds, and with expert design, this can be accomplished with little additional construction cost for materials over a conventional building. Very few industry experts have the skills or experience to fully capture benefits of the passive design. Passive solar designs are much more cost effective than adding expensive photovoltaic panels on the roof of a conventional inefficient building. A few kilowatt-hours of photovoltaic panels (costing 2 to 3 dollars per annual kW-hr production, U.S. dollar equivalent) may only reduce external energy requirements by 15% to 30%. A 100,000 BTU (110 MJ) high seasonal energy efficiency ratio 14 conventional air conditioner requires over 7 kW of photovoltaic electricity while it is operating, and that does not include enough for off-the-grid night-time operation. Passive cooling, and superior system engineering techniques, can reduce the air conditioning requirement by 70% to 90%. Photovoltaic generated electricity becomes more cost-effective when the overall demand for electricity is lower. [22] http://en.wikipedia.org/wiki/Zero-energy buildings

http://en.wikipedia.org/wiki/Energy_conservation

http://en.wikipedia.org/wiki/Renewable_energy



http://en.wikipedia.org/wiki/Solar_energy

http://en.wikipedia.org/wiki/Wind_energy

http://en.wikipedia.org/wiki/Passive_solar_building_design



http://en.wikipedia.org/wiki/Passive_house



http://en.wikipedia.org/wiki/Seasonal_energy_efficiency_ratio

http://en.wikipedia.org/wiki/Off-the-grid

http://en.wikipedia.org/wiki/Passive_cooling




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5.3 The Occupant’s Behaviour[22]

The energy used in a building can vary greatly depending on the behavior of its

occupants. The acceptance of what is considered comfortable varies widely. Studies of

identical homes in the United States have shown dramatic differences in energy use,

with some homes using more than twice the energy of others. Occupant behavior can

vary from differences in setting and programming thermostats, varying levels

of illumination and hot water, and the amount of miscellaneous electric devices used.


http://en.wikipedia.org/wiki/Thermostat

http://en.wikipedia.org/wiki/Over-illumination

http://en.wikipedia.org/wiki/Miscellaneous_electric_load




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CHAPTER 6

6.1 Development Efforts

Wide acceptance of zero energy building technology requires more government incentives or building code regulations, the development of recognized standards, or significant increases in the cost of conventional energy.

For example, the Google photovoltaic campus, and the Microsoft 480-kilowatt photovoltaic campus relied on U.S. Federal, and especially California state, subsidies and financial incentives. California is now providing $3.2 billion USD in subsidies for residential-and-commercial near-zero-energy buildings, due to California's serious electricity shortage, frequent power outages, and air pollution problems. The details of other American states' renewable energy subsidies (up to $5.00 USD per watt) can be found in the Database of State Incentives for Renewables and Efficiency.

[23]

In this section we shall analyze the contribution of certain organizations that are seen as stepping stones for promoting the net zero-energy culture as well as sustainable development as a whole. Some of these are:-

1. WBCSD - World Business Council for Sustainable Development

2. The “ Architecture 2030 ” Organization


http://en.wikipedia.org/wiki/Power_outage

http://en.wikipedia.org/wiki/Air_pollution




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6.2 WBCSD - World Business Council for Sustainable Development

The WBCSD was founded on the eve of the 1992 Rio Earth Summit to involve business in sustainability issues and give it a voice in the forum. The World Business Council for Sustainable Development (WBCSD) is a CEO-led, global association of some 200

companies dealing exclusively with business and sustainable development. [23]

The council believed that business could act as a catalyst for change toward the achievement of sustainable development; at the same time, business needs sustainable

development in order to fulfill its potential. [23]

Today, the WBCSD has some 200 members drawn from more than 35 countries and 20 major industrial sectors, involving some 1,000 business leaders globally. The Council also comprises a Regional Network of 55+ national and regional partner organizations – called Business Councils for Sustainable Development (BCSDs) – mostly located in

developing countries. [23]

The Council provides a platform for companies to explore sustainable development, share knowledge, experiences and best practices, and to advocate business positions on these issues in a variety of forums, working with governments, non-governmental and intergovernmental organizations.

The Council‘s objectives [24]

are to:

Be a leading business advocate on sustainable development; Participate in policy development to create the right framework conditions for

business to make an effective contribution to sustainable human progress; Develop and promote the business case for sustainable development; Demonstrate the business contribution to sustainable development solutions and

share leading edge practices among members; Contribute to a sustainable future for developing nations and nations in transition.

[23] http://www.wbcsd.org/History

[24] http://www.wbcsd.org/About the WBCSD

http://www.un.org/geninfo/bp/enviro.html

http://www.wbcsd.org/templates/TemplateWBCSD2/layout.asp?type=p&MenuId=NDEx&doOpen=1&ClickMenu=LeftMenu

http://www.wbcsd.org/includes/getTarget.asp?type=p&id=NjM&doOpen=1&ClickMenu=LeftMenu

http://www.wbcsd.org/History

http://www.wbcsd.org/About



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In order to achieve this, the Council focuses on four key areas: [25]

Energy and Climate Development The Business Role Ecosystems

6.21 WBCSD & the future

The WBCSD has launched a major initiative to support the development of ZEB‘S. Led by the CEO of United Technologies and the Chairman of Lafarge , and with the backing of both the support of large global companies and the expertise to mobilize the

corporate world and governmental support to make ZEB a reality [26]

. Their first report,

[Energy Efficiency in Buildings] a survey of key players in real estate and construction, indicates that the costs of building green are overestimated by 300 percent. Survey respondents estimated that greenhouse gas emissions by buildings are 19 percent of the worldwide total, in contrast to the actual value of roughly 40 percent.

During its first decade, the WBCSD was guided by the need to engage with business to highlight the importance of sustainable development and the relationship between business and sustainable development. Working through its membership, stakeholders, partners and regional networks, the WBCSD has reached out to an extensive network and assisted these diverse groups in articulating a common vision of the business contribution to sustainable development.

In 2005, realizing that the momentum for business engagement with sustainability issues had been created, the WBCSD decided that the time was ripe to look to the future and move towards advocacy. At its meeting in Nagoya, Japan, the WBCSD

adopted its strategy to 2015 [26]

. This strategy acknowledges that the world is shifting

towards partnerships between government, business and civil society to address the major challenges.

In order to respond adequately to this shift, the WBCSD has recognized that there is a need to more clearly articulate the business case for sustainable development; to encourage members to take a more active leadership role in sustainable development efforts; and to increase its outreach to those regions where the WBCSD‘s representation is presently weak.

[25] http://www.wbcsd.org/About the WBCSD

[26] http://www.wbcsd.org/History

http://www.wbcsd.org/includes/getTarget.asp?type=p&id=NjY&doOpen=1&ClickMenu=LeftMenu

http://www.wbcsd.org/includes/getTarget.asp?type=p&id=Njc&doOpen=1&ClickMenu=LeftMenu

http://www.wbcsd.org/includes/getTarget.asp?type=p&id=MTEzOA&doOpen=1&ClickMenu=LeftMenu

http://www.wbcsd.org/includes/getTarget.asp?type=p&id=NzE&doOpen=1&ClickMenu=LeftMenu

http://en.wikipedia.org/wiki/United_Technologies

http://en.wikipedia.org/wiki/Lafarge

http://www.wbcsd.org/About

http://www.wbcsd.org/History



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6.3 The “Architecture 2030” Organisation

Architecture 2030 is a U.S. based, non-traditional and flexible environmental advocacy group focused on protecting the global environment by using innovation and common sense to develop, and quickly implement, bold solutions to global warming as well as energy consumption. The organization was founded by Edward Mazria in 2003 in response to rapidly accelerating climate change. Locally, nationally and globally, Edward Mazria and Architecture 2030 have been responsible for reshaping the debate surrounding climate change, energy consumption and global greenhouse gas (GHG) emissions by identifying the ‗Building Sector‘. Data from the U.S. Energy Information Administration illustrates that buildings are responsible for almost half of all greenhouse gas emissions annually; globally, the percentage is even greater. The organization helped in bringing together the architects/planners, scientists, politicians, the media and academia to learn about and discuss the ‗Building Sector‘ and its role in

global warming. [27]

Architecture 2030‘s mission is to create, and quickly respond to, opportunities that shape the dialogue and address the crisis situation surrounding the ‗Building Sector‘ and its contribution to global warming. As discussed earlier, the ‗Building Sector‘ is the major source of demand for energy and materials that produce by-product greenhouse gases (GHG). Stabilizing and reversing emissions in this sector is key to keeping future

global warming under one degree Celsius (°C) above today‘s level. [27]

[27] http://en.wikipedia.org/wiki/Arcihtecture 2030

http://en.wikipedia.org/wiki/Edward_Mazria

http://en.wikipedia.org/wiki/Arcihtecture



Page | 27

6.31 'The 2030 °Challenge’ [28]

To accomplish this, and avoid dangerous climate change, Architecture 2030 has issued 'The 2030 °Challenge‘ foresees that the global architecture and building community adopt to the following targets:

All new buildings, developments and major renovations be designed to meet a fossil fuel, greenhouse gas (GHG) emitting, energy consumption performance standard of 50% of the regional (or country) average for that building type.

At a minimum, an amount of existing building area equal to that of new construction be renovated annually to meet a fossil fuel, greenhouse gas (GHG) emitting, energy consumption performance standard of 50% of the regional (or country) average for that building type.

The fossil fuel reduction standard for all new buildings be increased to: - 60% in 2010 - 70% in 2015 - 80% in 2020 - 90% in 2025 - Carbon-neutral by 2030 (zero fossil-fuel, GHG emitting energy to operate).

These targets may be accomplished through innovative design strategies epitomizing sustainable design, application of renewable technologies generating on-site renewable power and/or the purchase (maximum 20%) of renewable energy or certified energy credits.

To successfully impact global warming and world resource depletion, it is imperative that ecological literacy become a central tenet of design education. Yet today, the interdependent relationship between ecology and design is virtually absent in many professional curricula. To meet the immediate and future challenges facing our professions, a major transformation of the academic design community must begin today.

[28] http://en.wikipedia.org/wiki/Arcihtecture 2030




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CHAPTER 7

7.1 Overview

If anybody takes a look at the essentials of the numerous construction practices that focus on prolonging the overall life-span of the earth and the human race, one can easily find a common motto among all these practices – their prime objective is to reduce the impact of the built environment on the human health as well as the natural environment using techniques that are environmentally conscious and are mostly driven by the economic as well as political issues that are at present creating a havoc for this planet. One will also find that all these methods are actually the branches of a single tree and they are in a way linked to each other in a cyclic manner. In order to make a building ―sustainable‖, more than one of these practices can be amalgamated together to create a structure whose foot-print in totality has a very insignificant damaging impact on the environment. So the issue that arises is that if they all proceed to reducing the negative impact of the built environment on nature and humans, how is it that they are still different from each other??

7.2 Sustainable Architecture[29]

In general, this term describes the nature conscious design techniques formed to emphasize the minimization of negative impacts of buildings by highlighting energy efficiency and moderation in using materials, energy and space development; in a nutshell – it lays emphasis on an ecologically conscious approach to design.

Often used as a broad term it is a collection of many of the current practices of sustainability in architecture like green architecture, energy efficient architecture. However though, its emphasis lies in energy efficiency- reduction of energy consumption for a building and increasing the building‘s energy capture and generation potential. Its key aspects of concern are sustainable energy use, sustainable construction techniques and materials, waste and water management, negating carbon emissions, site aspect and their influence on design.

[29] http://en.wikipedia.org/wiki/Sustainable architecture

http://en.wikipedia.org/wiki/Sustainable



Page | 29

7.3 Green Architecture[30]

This practice, that dates back to the 1970‘s, aims at creating an environmentally responsible and resource-efficient architecture for a building‘s entire life-cycle taking into prior consideration all aspects of a building‘s life like design, siting, construction, operation, maintenance, renovation and demolition. It emphasizes on taking advantage of the renewable resources lie PV‘s for solar energy, wind turbines etc. It works by combining one or even more than one principles that reduce the buildings‘ negative impact on the environment like siting, water as well as materials efficiency, indoor environment quality, waste and toxics reduction etc.

7.4 Green VS Zero-Energy:: The Difference Energy efficiency is one part of Green Architecture which may or may not include any measures that may make a building a net-zero energy building. For example, to increase the energy efficiency of the building, the designer may use high efficiency windows as well as insulation for walls, ceilings, floors or include active or passive solar design systems to increase energy efficiency for the building. If the building meets its annual energy requirements from either on-site or off-site sources with very low carbon emissions, it may be termed as a zero-energy building. The difference between Green architecture and Zero-Energy architecture lies in the fact that Zero energy buildings achieve one key green-building goal of completely or very significantly reducing energy use and greenhouse gas emissions for the life of the

building. [30]

Zero energy buildings may or may not be considered "green" in all areas, such as reducing waste, using recycled building materials, etc. However, zero energy, or net-zero buildings do tend to have a much lower ecological impact over the life of the building compared with other 'green' buildings that require imported energy and/or fossil

fuel to be habitable and meet the needs of occupants. [31]

[30] http://en.wikipedia.org/wiki/Green buildings


http://en.wikipedia.org/wiki/Greenhouse_gas

http://en.wikipedia.org/wiki/Recycling

http://en.wikipedia.org/wiki/Green

http://en.wikipedia.org/wiki/Zero-energy%20buildings



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CHAPTER 8

8.1 Technologies & Techniques

Designing a building in the present scenario is considered as an environmental hazard. The energy use in buildings at an excessive rate is causing parallel damage to the environment. The implementation of energy intensive solutions to meet a buildings‘ demand for cooling, heating, ventilation & lighting is causing severe depletion of environmental resources. However, an integrated approach can increase energy resource efficiency in construction and fulfill the occupants‘ thermal and visual comfort requirements at reduced energy levels. Some steps[32] are:-

- Incorporation of solar passive techniques to minimize load on conventional systems

- Energy efficient design of HVAC & lighting systems - Use of renewable energy systems to share building load

- Use of low energy materials, construction methods & transportation energy. Low energy consumption in buildings can be achieved by studying site macro & micro climate, applying bioclimatic architectural principles to combat adverse conditions and taking advantage of desirable conditions. Certain elements that help in affecting thermal comfort conditions and the energy consumption are:-

- Landscaping - Ratio of built form to open spaces - Location of water bodies - Orientation - Plan form - Building envelope & fenestration

8.1.1 Landscaping

It alters the micro-climate and reduces direct sun striking and heating of the building, can cause a pressure difference, reduce air temperature using trees, grass, shrubs etc.

8.1.2 Ratio of Built Form to Open Spaces & Building Plan Form

For any given building form, the more compact the design the less wasteful it is in gaining/losing heat. [32] Energy Efficient Buildings in India – Mili Majumder



Page | 31

8.1.3 Location of Water Bodies

Water bodies modify the micro-climate, taking in large amount of heat in evaporation and causes significant cooling especially in the dry climates.

8.1.4 Orientation

Building orientation is affected by the various site features and the orientation depends on the site climate taking into account aspects of sunlight and wind direction so as to make these aspects desirable or undesirable to the different parts of the building.

8.1.5 Building Envelope & Fenestration

The various elements like building materials, roofing systems, walls, finishes, amount of fenestrations and shading determine the heat gains and losses and are quintessential in determining the effective building envelope performance.

ZEBs are normally optimized to use passive solar heat gain and shading, combined with thermal mass to stabilize diurnal temperature variations throughout the day, and in most climates are super-insulated. All the technologies needed to create zero energy buildings are available off-the-shelf today[33] . Zero-Energy Buildings are built with significant energy-saving features. The heating and cooling loads are lowered by using high-efficiency equipment, added insulation, high-efficiency windows, natural ventilation, and other techniques. These features vary depending on climate zones in which the construction occurs. Water heating loads can be lowered by using water conservation fixtures, heat recovery units on waste water, and by using solar water heating, and high-efficiency water heating equipment. In addition, day-lighting with sky-lights or solar-tubes can provide 100% of daytime illumination within the home. Nighttime illumination is typically done with fluorescent LED lighting that use 1/3 or less power then incandescent lights, without adding unwanted heat. And miscellaneous electric loads can be lessened by choosing efficient appliances and minimizing phantom loads or standby power. [33] http://en.wikipedia.org/wiki/Zero-energy buildings

http://en.wikipedia.org/wiki/Passive_solar

http://en.wikipedia.org/wiki/Thermal_mass

http://en.wikipedia.org/wiki/Diurnal_temperature_variation

http://en.wikipedia.org/wiki/Superinsulation

http://en.wikipedia.org/wiki/Commercial_off-the-shelf

http://en.wikipedia.org/wiki/Building_insulation

http://en.wikipedia.org/wiki/Daylighting

http://en.wikipedia.org/wiki/LED_lamp

http://en.wikipedia.org/wiki/Miscellaneous_electric_loads

http://en.wikipedia.org/wiki/Standby_power

http://en.wikipedia.org/wiki/Zero-energy%20buildings



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8.2 Eco-Design Strategies[34] The International Energy Agency, keen to promote the use of the most abundant energy source of all, the sun, has started a Solar Heating and Cooling Programme. Solar thermal energy is appropriate for both uses. Key applications for solar technologies are those that require low temperature heat, such as domestic water heating, space heating, pool heating, drying processes, and some industrial processes, Solar cooling works where the supply of sunny summer days is well matched with the demand – the desire for coolness indoors. The following table briefly describes certain eco-design strategies which are very commonly in the current practice:- Super insulation

High efficiency insulation materials, often including gases with

extremely low heat transfer values

High-performance

windows

Windows combining high level of light penetration with low level of

heat transfer, for example double-glazed windows.

Ventilation heat

recovery systems

Ventilation system that uses outgoing heated indoor air to pre-heat

incoming cold air.

Ground couple

heat exchangers

Uses the more stable ground temperature (cooler on hot days and

warmer of cold days) to adjust the temperature of incoming air.

Sunspaces/ Solarium Spaces heated by direct sun light.

Materials with

high thermal storage

capacities

Materials that keep their temperature for extended periods of time,

even if the surrounding air temperature changes, hence storing heat

gained during a hot day to heat the building during a cold night, and

vice versa.

Active solar

water systems

Water heating through direct sunlight, for example by leading water

through pipes located in the centre of concave steel mirrors focusing

sun light on the pipes.

Photovoltaic systems Panels with semi-conductor cells convert sun light to electricity

Integrated

mechanical system

Automated features of a building, e.g. sunshades, responding to

incoming sun light or indoor temperature so as to maintain

comfortable conditions.

Home automation

systems

Computer controlled heating, cooling and ventilation adjusting the

indoor temperature and ventilation according to pre-set parameters,

often designed to minimize energy use.

Energy-efficient

lights and appliances

Appliances and lights meeting minimum criteria for energy use per

output. For example, low-energy lamps often use about 30-40% less

energy to provide the same levels of light as ordinary lamps do.

Table 8.21: Design Strategies

[34] Harry Forster, Interrelate Grenoble - "Kick The Habit ", United Nations Environment Programme, Châtelaine,

Switzerland,2008



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8.3 The Passive Solar Building Design[35]

Passive solar building design uses a structure's windows, walls, and floors to collect, store, and distribute the sun's heat in the winter and reject solar heat in the summer. It can also maximize the use of sunlight for interior illumination. Passive solar buildings aim to maintain interior thermal comfort throughout the sun's daily and annual cycles whilst reducing the requirement for active heating and cooling systems. Passive solar building design is one part of low energy building design, and does not include active systems such as mechanical ventilation or photo-voltaics.

Main Elements:

As the figure 8.31 shows, every passive solar building includes five distinct design elements: - An aperture or collector — the large glass area through which sunlight enters the building. - An absorber — the dark surface of the storage element that absorbs the solar heat. - A thermal mass — the material that stores the absorbed heat. This can be masonry materials such as concrete, stone, and brick; or a water tank. - A distribution method — the natural tendency of heat to move from warmer materials to cooler ones (through conduction, convection, and radiation) until there is no longer a temperature difference between the two. In some buildings, this strictly passive distribution method is augmented with fans, ducts, and blowers to circulate the heat. - A control mechanism — to regulate the amount of sunlight entering the aperture. This can be as simple as roof overhang designed to allow more sunlight to enter in the winter, less in the summer. Passive design techniques include elements like:-

- Trombe walls (thermal mass walls, fig 8.32) - Daylighting systems - Water walls - Wind towers - Earth air tunnels -

[35] http://en.wikipedia.org/wiki/Passive_solar_building_design#Passive_solar_thermodynamic_principles



Page | 34

Fig 8.31: Design Strategies

Fig 8.32: Trombe Walls

Fig 8.33: skylight providing internal illumination



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8.4 Renewable Technologies[35]

Zero energy building design or any sustainable building design primarily incorporates renewable energy technologies as the first primary solution towards achieving zero-energy or energy efficiency. Technologies like BIPV’s(Building Integrated Photo-voltaics) and Wind Energy are the pre-dominant renewable technologies used extensively in building design. Other such technologies are:-

CHP system – CHP or the Combined heat and power system is an integrated system that provides a portion of the electrical load and recycles the thermal energy for space heating / cooling, process heating / cooling, dehumidification, domestic hot water.

Biomass & Biofuels – these are essentially organic wastes like food wastes and garbage, pulp and paper materials, sawdust, rice, wheat, flax straw, alfalfa , potato/sugar beet and other residues which are used as sources of energy production.

Fig 8.41:wind energy Fig 8.42:photovoltaics

Fig 8.43:bio-fuels

[36] Cliff Haefke , Energy Resources Center / University of Illinois at Chicago



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8.5 Case Studies The section illustrates the growth of zero energy architecture and the scale of each of the project is also quite remarkable as they vary from a building to an entire city. These studies illustrate an effective decline in the carbon emissions and demonstrate a highly regulated energy consumption. These case studies are:-

1. BedZED – Beddington Zero Energy Development, London . 2. Masdar City, Abu Dhabi . 3. The TERI Retreat Building, Gurgaon, India .

8.5.1 BedZED – Beddington Zero Energy Development, London[37]

Introduction:

Beddington Zero Energy Development (BedZED) is an environmentally-friendly housing development in Hackbridge, London, England. It is in the London Borough of Sutton. It was designed by the architect Bill Dunster to support a more sustainable lifestyle. The 99 homes, and 1,405 square metres of work space were built in 2000–2002.

Fig 8.5.1.1:BedZED, Street View ,Source : Wikipedia

Design principles : - Zero energy—The project is designed to use only energy from renewable sources generated on site.There are 777 m² of solar panels. Tree waste fuels the development's cogeneration plant

(downdraft gasifier) to provide district heating Fig 8.5.1.2:BedZED ,Source : Wikipedia

and electricity. -High quality—The apartments are finished to a high standard to attract the urban professional.Energy efficient—The houses face south to take advantage of solar gain, are triple glazed, and have high thermal insulation.

[37] http://en.wikipedia.org/wiki/BedZED

http://en.wikipedia.org/wiki/Low-energy_house

http://en.wikipedia.org/wiki/Hackbridge

http://en.wikipedia.org/wiki/London

http://en.wikipedia.org/wiki/England

http://en.wikipedia.org/wiki/London_Borough_of_Sutton



http://en.wikipedia.org/wiki/Bill_Dunster

http://en.wikipedia.org/wiki/Zero_energy_building

http://en.wikipedia.org/wiki/Photovoltaic_array

http://en.wikipedia.org/wiki/Cogeneration

http://en.wikipedia.org/wiki/District_heating

http://en.wikipedia.org/wiki/Solar_gain



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-Water efficient—Most rain water falling on the site is collected and reused. Appliances are chosen to be water-efficient and use recycled water when possible. A "Living Machine" system of recycling waste water was installed, but is not operating. -Low-impact materials—Building materials were selected from renewable or recycled sources within 35 miles of the site, to minimize the energy required for transportation. -Waste recycling—Refuse-collection facilities are designed to support recycling. -Transport—The development works in partnership with the United Kingdom's leading car-sharing operator, City Car Club. Residents are encouraged to use this environmentally friendly alternative to car ownership; an on-site selection of vehicles is available for use. -Encourage eco-friendly transport—Electric and liquefied-petroleum-gas cars have priority over cars that burn petrol and diesel, and electricity is provided in parking spaces for charging electric cars.

Performance :

Monitoring conducted in 2003 found that BedZED had achieved these reductions in comparison to UK averages:

- Space-heating requirements were 88% less

- Hot-water consumption was 57% less

- The electrical power used, at 3 kilowatt hours per person per day, was 25% less than the UK average; 11% of this was produced by solar panels. The remainder normally would be produced by a combined-heat-and-power plant fueled by wood chips, but the installation company's financial problems have delayed use of the plant.

- Mains-water consumption has been reduced by 50%, or 67% compared to a power-shower household.

Fig 8.5.1.3:BedZED Roofs, Source : Wikipedia

http://en.wikipedia.org/wiki/Living_machines



http://en.wikipedia.org/wiki/Car_sharing

http://en.wikipedia.org/wiki/City_Car_Club

http://en.wikipedia.org/wiki/Liquefied_petroleum_gas

http://en.wikipedia.org/wiki/Gasoline

http://en.wikipedia.org/wiki/Electrical_power

http://en.wikipedia.org/wiki/Kilowatt_hour

http://en.wikipedia.org/wiki/Combined_heat_and_power

http://en.wikipedia.org/wiki/Drinking_water



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8.5.2 Masdar City , Abu Dhabi[38]

Introduction:

Masdar City is a 6 sq km sustainable development that uses traditional Arabic planning principals, together with existing and future technologies, that will redefine the design

and construction of cities in the future. Masdar has 5 integrated units[39]

:-

1 Masdar City A living city that will house around 1,500 Cleantech companies with 40,000 residents and 50,000 commuters, and provide a research and test base for its technologies.

2 Masdar Institute of Science and Technology Developed in cooperation with the Massachusetts Institute of Technology (MIT), The Masdar Institute will eventually host 800 students and 200 faculty members.

3 Utilities and Asset Management The Utilities team is a renewable energy project developer focusing on concentrated solar power (CSP), photovoltaic (PV), wind, and waste-to-energy both locally and internationally. A hydrogen fi red power plant in Abu Dhabi will be the world‘s first and produce over 500MW of power.

4 Carbon Management Aims to drive the progress of low carbon economies around the world while capitalising on monetizing carbon emission reduction projects. The Carbon Management Unit is also developing a carbon capture and storage network within the Emirate of Abu Dhabi.

5 Industries Developing large-scale, strategic clean energy projects locally and internationally including a PV production facility in Germany and Abu Dhabi and a 4 sq km solar manufacturing cluster also in Abu Dhabi. It‘s salient features include: • 100% renewable energy • Carbon neutral city • Zero waste • Highest quality of life • Global exemplar of sustainability research and development in practice planning • Best-in-class technology, thinking, architecture and planning

[38] Masdar city brochure report

[39] http://www.masdarcity.ae/en/index.aspx



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Fig 8.5.2.1: the Masdar City Fig 8.5.2.2: the Masdar City Master Plan

Environmental Features: [40]

Responsive to the culture and spirit of Abu Dhabi, the design of the city is inspired by the traditional Arabic architecture and urban planning of the region and includes many examples of where traditional design techniques help to reduce energy consumption and to improve the quality of the environment. Shaded walkways and narrow streets reduce glare and solar gain, and create pleasant and attractive outside green spaces. The diagonal orientation of the streets and public spaces makes best use of the cooling night breezes and lessens the effect of hot daytime winds, whilst further reducing the effects of direct sunlight. Traditional passive features such as wind towers and blinds and solar shades help to further improve comfort levels. The buildings in the city are amongst the most advanced in the world. Intelligent design of residential and commercial spaces reduces the need for artificial lighting and air conditioning. All buildings will surpass the highest standards currently set by internationally recognized organizations and Masdar City is a key partner in the Estidama programme which sets new benchmarks in planning, design and building within cities.




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Power[41]

: A standard city would draw power from a distant power station fired by coal,

oil, gas or nuclear fuel. At Masdar, the following technologies are used: 1.Photovoltaic technology - Extensive use of photovoltaic technology is proposed, both to provide the base power load during the construction phase and integrated into the city at roof level.

2.Concentrating solar power(CSP) - CSP technology will be used to provide electricity and heat for the production of cooling with absorption chillers. The high temperature heat produced can be stored for overnight use with molten salt technology. 3.Evacuated tube collectors(ETC) - ETC will be integrated into buildings to provide hot water and a base load which can be used for cooling. 4.Geothermal- This will provide a constant source of high temperature water or steam for the production of 24-hour cooling. 5.Waste to energy- Products that cannot be recycled can be converted into energy by incineration using a number of technologies including gasification, pyrolysis and plasma arc gasification.

Fig 8.5.2.3: the Masdar City Power Energy Diagram




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8.5.3 RETREAT: Resource Efficient TERI Retreat for Environmental Awareness and Training, Gurgaon

Introduction:

The RETREAT[42]

building is a major step taken forward by TERI to create a model

sustainable building complex. This building in quite honesty does not put any pressure on the already depleting natural resources and the ecosystems and actually regenerates what it consumes in terms of energy. The building offer‘s a high level of visual as well as thermal comfort with a minimum environmental footprint and is replicable in part or in whole.

Project details

Project description- 30-room training hostel with conference and ancilliary facilities

Climate – Composite

Building type- Institutional

Architects- Sanjay Prakash and TERI

Year of start/completion- 1997–2000

Client/owner- Tata Energy Research Institute, New Delhi

Covered area- 3000 m²

Cost of the project- Civil works - Rs 23.6 million; Electrical works - Rs 2.5million; Cost of

various technologies - Rs 18.54 million

Fig 8.5.3.1: the TERI Rtreat front entrance, Source: TERI

[42]TERI



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Design features:

- Wall and roof insulation - Building oriented to maximise winter gains; summer gains offset using shading. - East and west walls devoid of openings and are shaded - Earth air tunnel for rooms – four tunnels of 70-m length and 70-cm diameter each laid at a depth of 4 m below the ground to supply conditioned air to the rooms - Four fans of 2 hp each force the air in and solar chimneys force the air out of rooms

Fig 8.5.3.2: the TERI Rtreat rear view, Source: TERI

- Hybrid system with 50 kW biomass gasifier and 10.7 kWp solar photovoltaic with inverter and battery backup to power the building - 2000 lpd building integrated solar water heating system - Energy-efficient lighting provided by compact fluorescent lamp, high efficiency fluorescent tubes with electronic chokes

Fig 8.5.3.3: Red Stone Jali as External Facade, Source: TERI

- Daylighting and lighting controls to reduce consumption - Waste water management by root zone system

Fig 8.5.3.4: the solar panels, Source: TERI



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CHAPTER 9

9.1 Conclusions

With the energy crisis rising at a steady rate, the question one has to ask is:: ―are zero energy buildings the much needed solution??‖. Like any sustainable technology this too has its drawbacks and its plusses, hence, a list of features has been jotted down below that serve as a definite conclusion for this dissertation:- Advantages:-

- isolation for building owners from future energy price increase - increased comfort due to more-uniform interior temperatures - reduced requirement for energy austerity - reduced total net monthly cost of living - improved reliability - the value of a ZEB building relative to similar conventional building should

increase every time energy costs increase - extra cost is minimized for new construction compared to an afterthought

retrofit Disadvantages:-

- initial costs can be higher - very few designers or builders have the necessary skills or experience to

build a ZEB - possible declines in future utility company renewable energy costs may

lessen the value of capital invested in energy efficiency - it is a challenge to recover higher initial costs on resale of building - climate-specific design may limit future ability to respond to rising-or-falling

ambient temperatures - without an optimized thermal envelope the embodied energy, heating and

cooling energy and resource usage is higher than needed. ZEB by definition do not mandate a minimum heating and cooling performance level thus allowing oversized renewable energy systems to fill the energy gap.

The backbone of zero energy architecture depends severely on the monitoring process as well as the improvement of operations which can either make or break the zero-energy goals, but rest assured, as various zero-energy projects are being completed, occupied and monitored; the building industry has raised the bar for sustainable development, and many developers and building industry professionals are eager to compete and take on these challenges. These targets are also spurring substantial investment from clean tech investors that may lead to disruptive industry breakthroughs and make these goals more achievable

http://en.wikipedia.org/wiki/Austerity

http://en.wikipedia.org/wiki/Cost_of_living



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References

Documents

- Zero Energy Buildings: A Critical Look at the Definition- P. Torcellini, S. Pless, and

M. Deru National Renewable Energy Laboratory

Understanding Zero-Energy Buildings -By Paul A. Torcellini, Ph.D., P.E., Member

ASHRAE; and Drury B. Crawley, Member ASHRAE - Net zero energy buildings: definitions, issues and experience – European Council

for an energy efficient economy

- Energy-Efficient Buildings in India – Mili Majumder Tata Energy Research Institute

- India: The Way Towards Energy and resource efficient buildings- Bureau of Energy Efficiency

- Renewables for Net Zero Energy Installation- Dr. Andy Walker, NREL, "Renewable Energy Optimization for Net-Zero"

- Power & Energy Architecture for NZE - Cliff Haefke, Energy Resources Center /

University of Illinois at Chicago

- Power & Energy Architecture for NZE Buildings: Thermal Management - Dr. Stephan Richter, GEF Ingenieur AG

- Biofuels and Bioenergy on U.S. Military Bases - Chris J. Zygarlicke, Energy & Environmental Research Center University of North Dakota

- Engineering Analysis of Fuel Cells and Hybrid Technologies for Support of the

Net-Zero Energy Concept - Jack Brouwer, Ph.D., Associate Director, National Fuel Cell Research Center, University of California - Net Zero Energy Building - Paul Hutton & Pete Jefferson

- BIPV for NZE Installations & Deployed Bases - Cécile Warner, P.E.NREL

- Wind Energy: Technology & Applications – Tony Jiminez



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-Zero Net Energy Buildings - Ellen Watts AIA, LEED AP Architerra Inc. -centerline- Newsletter of the Center for the Built Environtment at the University of Carlifornia, Belrkeley - Energy Efficiency in Buildings- business realities & opportunities - World Business Council for Sustainable Development - Getting to Zero Energy Buidings : AEDG’s to ZEB’s – Drury B Crawley, U.S. Department of Energy - Developments in Photovoltaics - Kevin Lynn, Senior Research Engineer; FLORIDA SOLAR ENERGY CENTER

Weblinks

- http://www.Architecture2030.com/Why - http://www.zeroenergycbc.org - http://en.wikipedia.org/wiki/Zero-energy buildings - http://www.wbcsd.org/ - http://en.wikipedia.org/wiki/Arcihtecture 2030 - http://en.wikipedia.org/wiki/Sustainable architecture - http://en.wikipedia.org/wiki/Green buildings - http://en.wikipedia.org/wiki/Passive solar building design - http://en.wikipedia.org/wiki/BedZED

- http://www.masdarcity.ae/en/index.aspx

http://www.architecture2030.com/Why


http://www.wbcsd.org/


http://en.wikipedia.org/wiki/Sustainable

http://en.wikipedia.org/wiki/Green

http://en.wikipedia.org/wiki/Passive

Zero Energy Architecture-2

Documents

Transcript of Zero Energy Architecture-2