Home Articles New Designing Sustainable Green Building: Focus on Energy Conservation – Part I

Designing Sustainable Green Building: Focus on Energy Conservation – Part I

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A.N.Sarkar

 

Dr. A N Sarkar
Ex-Senior Professor (International Business) & Dean (Research), Asia-Pacific Institute of Management, New Delhi

 

Introduction

Global Sustainability Goals (GSG) have led to the development of the Green building movement. The Green Building Programme, stemming from the movement, has had unprecedented success as it provides a quantifiable metric to people’s efforts towards Sustainable development. Sustainable development and Green buildings are often used interchangeably. Although, sustainable development and Green buildings are related, they are not the same. Green Building is the “practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building Life-cycle from sitting to design, construction, operation, maintenance, renovation, and deconstruction.” This definition has evolved over the years. “Green Buildings” is an ever evolving, dynamic term. Green building is the status of our efforts in attaining sustainability in construction practices. As technology evolves and new materials are developed, the status of our efforts are also changing. Hence, the essence of Green buildings is changing. Some of the key sustainable features of Green building may accordingly be summed up as follows:

– The building is fully compliant with the ECBC (Energy Conservation Building Code).
– Sustainable site planning has been integrated to maintain favourable microclimate.
– The architectural design has been optimized as per climate and sun path analysis.
– The building has energy-efficient artificial lighting design and daylight integration.
– Water body to cool the micro climate.
– Orientation of building: North – South.
– It also has energy-efficient air conditioning design with controls integrated to reduce annual energy consumption.
– Passive strategies such as an earth air tunnel have been incorporated in the HVAC design to reduce the cooling load.

A Green building is one whose construction and lifetime of operation assure the healthiest possible environment while representing the most efficient and least disruptive use of land, water, energy and resources. The optimum design solution is one that effectively emulates all of the natural systems and conditions of the pre-developed site – after development is complete. This paper provides an overview of how green building relates to sustainable development practices in the special context of Energy Conservation.

The expression “Passive building” refers to a construction standard that can be achieved using various types of construction materials. It can also mean a Green building construction that guarantees an interior climate as comfortable in summer as it is in winter without a conventional heating system. Taken from the German word “Passivhaus,” this expression concerns both collective and individual habitats. The purpose of the “Passivhaus” is to reduce energy consumption in residential buildings by capturing a passive solar energy contribution, reinforcing building insulation, using renewable energies and recuperating heat. Individual passive houses are often compact. This is one condition for achieving low energy consumption. To build a ‘Passive building’, the following requirements must be satisfied: High quality triple-glazed windows; Building orientation to capture Passive solar energy etc..

1.0. Benefits of Green Building

The benefits of Green building are well-documented. The USGBC estimates that green building, on average, currently reduces energy use by 30 percent, carbon emissions by 35 percent, and water use by 30 to 50 percent, and generates waste cost savings of 50 to 90 percent (Green Outlook, 2011). In addition, green building can help foster stronger communities and provide important benefits to human health and productivity. The following profiles are offered as examples of new and retrofitted construction in different climates in the three countries as a modest attempt to illustrate something of the variety possible in commercial, institutional, and residential green building.

Saving Energy

Green building addresses climate change and other energy-related air emissions in two basic ways: first (and most importantly), by reducing the amount of energy used to light, heat, cool and operate buildings and their appliances, and second, by substituting for what currently is mostly carbon-based energy with alternatives that do not involve the production of greenhouse gases and other harmful air emissions. It is common now for more advanced green buildings to routinely reduce energy usage by 30, 40, or even 50 percent over conventional buildings, with the most efficient buildings now performing more than 70 percent better than conventional properties.

Improving Water Usage

Green building uses a number of techniques to improve water quality and availability. These techniques can help reduce water usage, provide for on-site cleaning and reuse of wastewater, and on-site filtering of storm water. Water management is a significant cost and an important environmental issue in all three countries. Water stress is particularly high in parts of Mexico, the United States, and western Canada.

Reducing Wastes

Reducing waste through better product design, recycling, and re-use of materials will result in tremendous reductions in both raw material usage and also in associated environmental impacts, as well as the cost to the private sector and local governments of disposing of these materials. Building-related construction and demolition debris totals approximately 136 million tons per year in the United States, accounting for nearly 60 percent of the total non-industrial waste generation there (U.S. Environmental Protection Agency). An estimated 20 to 30 percent of building-related construction and demolition debris is recovered for processing and recycling. In Canada, construction, renovation, and demolition waste accounts for about 17 to 21 percent of the total mass of waste land-filled annually (Watson, 2011). The volume of demolition waste in Mexico City is estimated between 3,500 and 5,000 tons a day. Reducing construction waste and creating reusable and recyclable building components are key strategies in addressing these environmental impacts.

Reduction of GHG Emissions

Reports from leading scientists throughout the world underline the need for urgent global action on climate change. The IPCC projects that without more immediate action to limit greenhouse gas emissions, global warming could cause irreversible and possibly catastrophic consequences.

Three recent reports illustrate that energy-efficient buildings are one of the quickest and cheapest ways to reduce significantly greenhouse gas emissions.

Mitigating Climate Change and rendering Economic benefits

According to a recent IPCC report, buildings represent the greatest opportunity for considerable reductions in CO2 emissions. Its fourth assessment report states that about 30 percent of the projected global greenhouse gas emissions in the building sector can be avoided by 2030 with net economic benefit (IPCC Fourth Assessment Report, 2007). According to the report, limiting CO2 emissions would also improve indoor and outdoor air quality, improve social welfare, and enhance energy security.

Using Green Space and Local Vegetation

Features such as gardens and green walls provide much better experiences for users. Low water-use plants can also help improve air quality.

High Quality Property Management

Good auditing, metering, and care of the property can ensure that the energy and water savings from a green building are captured (Figure 1).

Figure 1 The River-House Development Project in Manhattan’s Battery Park City
Figure 1 The River-House Development Project in Manhattan’s Battery Park City

 

 

 

 

 

 

1.0. Fundamental Principles of Green Building and Sustainable Site Design

Sustainable Site Design Key Principles include the following: Minimize urban sprawl and needless destruction of valuable land, habitat and green space, which results from inefficient low-density development. Encourage higher density urban development, urban re-development and urban renewal, and Brownfield development as a means to preserve valuable green space. Preserve key environmental assets through careful examination of each site. Engage in a design and construction process that minimizes site disturbance and which values, preserves and actually restores or regenerates valuable habitat, green space and associated eco-systems that are vital to sustaining life.

1.1. Key Strategies and Technologies

Subscribing to the above perceptions the following should ideally be some of the key strategies and technologies that can be put in place for achieving sustainable site designs of Green building in green space.

– Make more efficient use of space in existing occupied buildings, renovate and re-use existing vacant buildings, sites, and associated infrastructure and consider re-development of Brownfield sites. Design buildings and renovations to maximize future flexibility and reuse thereby expanding useful life.
– When new development is unavoidable, steer clear of sites that play a key role in the local or regional ecosystem. Identify and protect valuable Greenfield and wetland sites from development.
– Recognize that allowing higher density development in urban areas helps to preserve green space and reduce urban sprawl. Invest time and energy in seeking variances and regulatory reform where needed.
– Evaluate each site in terms of the location and orientation of buildings and improvements in order to optimize the use of passive solar energy, natural day-lighting and natural breezes and ventilation.
– Make best use of existing mass transit systems and make buildings and sites pedestrian and bike friendly, including provisions for safe storage of bicycles. Develop programs and incentives that promote car-pooling including preferred parking for commuters who carpool. Consider making provisions for re-fueling or recharging alternative fuel vehicles.
– Help reduce the urban heat island effect by reducing the building and site development footprint, maximizing the use of pervious surfaces, and using light colored roofs, paving, and walkways. Provide natural shading of buildings and paved areas with trees and other landscape features.
– Reduce impervious areas by carefully evaluating parking and roadway design. Pursue variances or waivers where local ordinances may unintentionally result in the over-design of roadways or parking.
– Optimize the use of on-site storm water treatment and ground water recharge. Minimize the boundaries of the construction area, avoid needless compaction of existing topsoil, and provide effective sedimentation and silt control during all phases of site development and construction.
– Use landscape design to preserve and restore the region’s natural habitat and heritage while emphasizing the use of indigenous, hardy, drought resistant trees, shrubs, plants and turf.
– Help reduce night-time light pollution by avoiding over-illumination of the site and use low cut-off exterior lighting fixtures which direct light downward, not upward and outward.
To start off with the learning process, here, in rough order of importance, are seven key Green building concepts.

1. Design

The single most important green design decision is size. Smaller houses automatically consume fewer resources both during construction and after occupation. “Houses should be sized to work for you every day,” says Sarah Susanka, architect and author of ‘The Not So Big House’. Susanka further suggests that we stick to basic shapes. “Simpler forms lose less energy because the ratio of exterior surface area to volume is smaller. Every projection from a house is like a cooling fin.”

Solar orientation is the most important design element. Heating and cooling loads in a home could be cut significantly by orienting the long walls of houses east-west, exposing south facing windows in winter, and shading them in summer, and avoiding expanses of glass on west-facing walls that get the full brunt of the flat afternoon sun. Even in lots where the street dictates layout of the home, there are still steps you can take. One can reverse plans to place the garage on the west side of a house. Porches and broad roof overhangs can shade south and west facing windows. Plant, or don’t cut down in the first place, trees that shade the west side of a house.

2. Durability

Moisture control is a huge focus of building science–inspired components like generous overhangs, proper window and door flashings, and rain-screen walls that allow siding to dry, improve paint durability, and avoid water wicking. Normal construction details assume greater importance. Controlling air and moisture leakage from inside to out not only saves energy, but also can prevent damaging condensation from forming in framing cavities. The use of vapor barriers in cold climates is an important moisture control element. Attention to detail is another key. We must follow a careful step-by-step flashing, sealing, and installation sequence to ensure proper performance over the life of the building. Other details can be as basic as properly installing house-wrap or builder’s felt as a secondary weather barrier, so that water that gets in behind the siding was directed out again.

3. Energy Efficiency

Insulation is a job that needs careful detailing. From a green perspective, this is very important. And air sealing-filling the holes where inside air can leak out or outside air can leak in-is at least as important as insulation, because no insulation can achieve its potential if air can leak through it. Air infiltration must be kept as low as possible. It is vital to eliminate areas that allow inside air access to the thermal envelope, including areas behind bathtubs, showers, and kitchen soffits. These areas should be closed off from the wall behind them with an air and moisture barrier. Recessed ceiling lights are another source of leakage. New models are available that are air sealed to help control infiltration.

Fluorescent lighting gives more light for your energy dollar, (compared to incandescent or halogen), and they also produce less heat than incandescent and halogens and can save significantly on cooling loads. Fluorescent lights don’t necessarily give off a sickly green light anymore, either. Commonly available lamps with a color temperature of 2,600 to 2,800 Kelvin give off light that’s nearly indistinguishable from a cool white incandescent bulb. Supplying Energy Star–rated appliances is another simple way to cut down energy use. Similar Energy Star–rated appliances can vary in actual consumption, so go one step further and compare annual energy use printed on each appliance’s label.

4. Waste Reduction

If ever there was a green building strategy that’s a no-brainer, waste reduction is it. A simple expedient is to design in 2-foot modules to use materials most efficiently. Optimum Value Engineering is an approach to framing that questions the use of every stick of lumber to optimize materials use. For example, most openings don’t require double 2×12 headers for structural purposes. If a double 2×12 can be replaced with a single member, it will save lumber and create space to add insulation. Recycling is another simple approach. Cardboard and metal are easy to recycle. Not only does this keep material out of the landfill, but recycling saves some of the cost of buying new, and saves the cost of a Dumpster.

5. Indoor Air Quality

If there is a downside to air sealing, it is the potential to trap pollutants inside. Typical indoor pollutants include formaldehyde (off-gassing from OSB, most forms of particle board, and some carpet and their glues), volatile organic compounds (VOCs) (solvents from paints, finishes, automotive products, etc.), combustion by-products such as carbon monoxide (from gas stoves and any improperly vented fuel-burning appliance), and excessive moisture. There are two approaches to improving indoor air quality (IAQ). The first is reducing the use of products that off-gas. Use plywood floor sheathing, which off-gasses less formaldehyde than OSB. Detached garages separate exhausts, fuel, and pesticide storage from living spaces. Providing dedicated combustion air for furnaces, boilers, and water heaters can prevent back-drafting stack gasses into the house.

Proper ventilation, the second approach, is as important as reducing sources. Using Heat Recovery Ventilators (HRVs) in northern climates bring fresh outside air in, while exhausting stale inside air. The two air streams pass each other in the ventilator’s heat exchanger, with the outgoing indoor air tempering the incoming outdoor air. An added benefit is that in the winter an HRV ventilates the house and retains some indoor humidity. It exhausts air from bathrooms, and laundry and kitchen areas, and directs the tempered incoming fresh air into the living areas and bedrooms.

6. Water Conservation

Many of us remember the inadequate flushing and frequent clogs from the federally mandated change to 1.6-gallons-per-flush toilets in the 1980s. But that has changed, and low-consumption toilets perform very well today. Water issues also include managing storm-water runoff to maintain natural ground percolation that recharges aquifers, as well as preventing siltation of waterways. It’s often possible to reduce the storm sewer infrastructure by increasing the ability of individual home sites to absorb storm flows. Techniques include draining roof runoff to absorption fields and the use of pervious concrete pavers on driveways. This approach may even ease the path through local land-use boards by showing that you are doing the right thing.

7. Focus on Green Products

Simply choosing one product over another is the easiest, yet the least important path to going green. Look for swaps that take something not as green and replace it with something greener that requires no changes in worker skills. Examples include specifying concrete that incorporates fly ash (a waste product from coal-burning power plants) as a partial substitute for Portland cement. Another example is using bamboo flooring, which regenerates quickly, instead of wood species that are not as sustainable. Look for Forest Stewardship Council certified lumber and low-VOC paints. Although low-VOC paints cost a little more, the major brands all include a mildew-cide, which makes them an easy sell. Prefab foundation panels are one possible swap. Not only does a Superior Wall foundation go up in a day, its waterproof, it requires no concrete footer, and it’s insulated. Elk’s reflective roof shingles are another, which use a 3M mineral coating that reflects about 25 percent of unwanted solar radiation versus other shingles.

2.0. Sustainable Architecture and Green Design: The Concept

Sustainable architecture and green design have become one of the most widespread areas of focus in the scholarly studies related to build environments. Accordingly, with view to the environmental assessment and energy performance of buildings, it is vital to develop an overview of current theoretical perspectives, trends, applications and constraints towards the development of green environmentally sustainable buildings. To confirm that, previous studies put forward a theory representing that the performance of green buildings is substantially related to the level of their environmental assessment, thus, versatile studies highlight the necessity of the identification and consideration of sustainable energy performance indicators in the environmental evaluation and any green implementations. In this regard, the building energy efficiency, the thermal performance of buildings and the material efficiency are considered as significant parameters of sustainable energy performance indicators to be fully taken into consideration during the performance evaluations (Mwasha et al, 2011). According to the study by Joelsson (2009), with view to the effectiveness of green buildings towards decreasing the use of energy and its negative impacts on the environment, there are fundamental strategies including ‘reducing the energy demands’, ‘enhanced energy efficiency’ and ‘application of passive design techniques’. Likewise, the utilization of appropriate building envelopes is influential in more than half of the embodied energy distribution in a building, particularly in residential buildings (COAG, 2009).

The building industry is a vital element of any economy but has a significant impact on the environment. By virtue of its size, construction is one of the largest users of energy, material resources, and water, and it is a formidable polluter. In response to these impacts, there is growing consensus among organizations committed to environmental performance targets that appropriate strategies and actions are needed to make building activities more sustainable (Mwasha et al, 2011). With respect to such significant influence of the building industry, the sustainable building approach has a high potential to make a valuable contribution to sustainable development. Sustainability is a broad and complex concept, which has grown to be one of the major issues in the building industry. The idea of sustainability involves enhancing the quality of life, thus allowing people to live in a healthy environment, with improved social, economic and environmental conditions (Ghaffarian et al, 2011). A sustainable project is designed, built, renovated, operated or reused in an ecological and resource efficient manner (Alnaser et al, 2008). It should meet a number of certain objectives: resource and energy efficiency; CO2 and GHG emissions reduction; pollution prevention; mitigation of noise; improved indoor air quality; harmonization with the environment (Yilanci et al, 2009). An ideal project should be inexpensive to build, last forever with modest maintenance, but return completely to the earth when abandoned (Ghaffarian et al, 2009).

2.2. An Integrated View of Green Buildings – Life Cycle Engineering

Green Buildings are buildings of any usage category that subscribe to the principle of a conscientious handling of natural resources. This means causing as little environmental interference as possible, the use of environmentally friendly materials that do not constitute a health hazard, indoor solutions that facilitate communication, low energy requirements, renewable energy use, high-quality and longevity as a guideline for construction, and, last but not least, an economical operation. In order to achieve this, an integrated, cross-trade approach is required to allow for an interface-free, or as interface-free as possible, handling of the trades of architecture, support structure, façade, building physics, building technology and energy while taking into account both usage considerations and climatic conditions. To this end, innovative planning and simulation tools are employed, according to standards, during the design and planning stages for Green buildings. They allow for new concepts since – by means of simulation of thermal, flow and energy behaviour – detailed calculations can be achieved already during the design stage. Attainable comfort levels and energy efficiency can thus be calculated in advance and this means that, already during the design stage, it is possible to achieve best possible security in regards to costs and cost efficiency.

Equipped with these kinds of tools, Green Building designers and planners can safely tread new paths where they may develop novel concepts or products. Aside from an integrated design and work approach, and the development and further development of products and tools, sustainability must be expanded so that the planners are able to gather valuable experience even during the operation of the buildings. This is the only way that a constructive back-flow of information into the building design process can be achieved, something that, until now, does not apply for contemporary building construction. This approach is to be expanded to encompass renaturation, in order to make allowances for the recycling capability of materials used even during the planning stage. In other industrial sectors, this is already required by law but, in the building sector, we are clearly lagging behind in this aspect. On account of consistent and rising environmental stress, however, it is to be expected that sustainability will also be demanded of buildings in the medium-term and thus not-too-distant future. The path from sequential to integral planning, hence, needs to be developed on the basis of an integral approach to buildings and is to be extended in the direction of a Life-Cycle engineering approach. This term stands for integral design and consultation knowledge, which always evaluates a given concept or planning decision under the aspects f its effects on the entire Life-cycle of a given building (Figure 2). This long-term evaluation, then, obliges a sustainable handling of all resources; including natural resources.

Figure 2 Life-Cycle Engineering approach of Green Building Products
Figure 2 Life-Cycle Engineering approach of Green Building Products

 

 

 

 

 

 

 

3.0. Concept of Energy Efficiency of a Building

The energy efficiency of a building is the extent to which the energy consumption per square metre of floor area of the building measures up to established energy consumption benchmarks for that particular type of building under defined climatic conditions. Building energy consumption benchmarks are representative values for common building types against which a building’s actual performance can be compared.

The benchmarks can be derived by analysing data on different building types within a given country. The typical benchmark is the median level of performance of all the buildings in a given category and good practice represents the top quartile performance. Comparisons with simple benchmarks of annual energy use per square metre of floor area or treated floor area (kWh/m2 /annum) allow the standard of energy efficiency to be assessed and priority areas for action to be identified. Benchmarks are applied mainly to heating, cooling, air-conditioning, ventilation, lighting, fans, pumps and controls, office or other electrical equipment, and electricity consumption for external lighting (Figure 3). The benchmarks used vary with the country and type of building. The measure of heat loss through a material, referred to as the U-Value, is also used as a way of describing the energy performance of a building. The U-value refers to how well an element conducts heat from one side to the other by rating how much the heat the component allows to pass through it. They are the standard used in building codes for specifying the minimum energy efficiency values for windows, doors, walls and other exterior building components. U-values also rate the energy efficiency of the combined materials in a building component or section. A low U-value indicates good energy efficiency. Windows, doors, walls and skylights can gain or lose heat, thereby increasing the energy required for cooling or heating. For this reason most building codes have set minimum standards for the energy efficiency of these components. In this regard, a typical energy flow pattern in a building is illustrated in Figure 3 below.

Figure 3 A Typical Energy Flow pattern in a Building
Figure 3 A Typical Energy Flow pattern in a Building

 

 

 

 

 

The building’s gross energy needs represent the anticipated buildings requirements for heating, lighting, cooling, ventilation, air conditioning and humidification. The indoor climate requirements, 8 outdoor climatic conditions and the building properties (surface/transmission heat transfer and heat transfer due to air leakage) are the parameters used for determining what the gross energy needs of the building will be. As illustrated in the diagram above (Figure 3), delivered energy, natural energy gains and internal heat gains all contribute to providing the energy needs of a building.

3.1. Criteria for Green Building: LEED Certification

There has been a realization that building design plays an important role in our society, and that sustainable design is crucial not only to human well being but also the well being of our environment. This has led to the evolution of sustainable building practices. To recognize those who have taken the initiative to implement green building design, the U.S. Green Building Council introduced the LEED rating system. To date, LEED encompasses 17,000 registered and 2,200 certified projects in 91 countries.
The Leadership in Energy and Environmental Design (LEED) Rating System has become a national standard synonymous with green building design. LEED is a third-party, points-based certification program made available for public use in 2000 by the United States Green Building Council (USGBC). The rating system reflects the USGBC dedication to the promotion of sustainable building practices. LEED certification is dependent upon a series of criteria developed in collaboration with industry professionals and experts in a consensus-based process to establish what determines a high-performance structure. Criteria established for all certification categories address five key areas for the improvement of human and environmental health. The core categories of criteria of the LEED program influence the sub-criteria and possible points awarded to high-performance structures. Structures are awarded a points-based score for the particular technological and mechanical innovations incorporated to satisfy established criteria requirements. Criteria items are assessed and awarded a given number of points for the project-specific application.

The final total of awarded points determines the level of LEED certification awarded to the project. Structures are assessed according to the category-specific criteria developed to measure high-performance provisions. Upon completion of construction and project assessment, one of four levels of certification is awarded to the structure. The four levels of LEED-Certification Procedure and the criteria for achievement are listed in Table 1.

Table 1 Attainment Criteria for LEED Certification
Table 1 Attainment Criteria for LEED Certification

 

 

 

 

 

3.1.1. LEED Green Building Rating System

LEED is a highly quantified and systematic approach to buildings of all types. Because it has accomplished so much and been so broadly accepted, LEED is becoming the standard by which many green buildings are measured. LEED quantifies a building’s performance in the following major categories as shown in Table 2. LEED operates through the U.S. Green Building Council (USGBC) and takes a much broader “triple bottom line” approach considering people, planet and profit, not just energy use. The triple bottom line factors in the economic, environmental and social issues present throughout the entire building process from concept, design, development and future operation.

Table 2 LEED Scoring and Rating Award for New Construction Building &
Table 2 LEED Scoring and Rating Award for New Construction Building &

 

 

 

 

 

4.0. Sustainable Energy Performances of Green Building

Back to US Congress 1992 towards assessment of building energy efficiency, there has been attempts to educate the professionals and ordinary people towards the considerable substance of building energy, level of consumption and conservations for future. The study states that this level of consumption and conservation is highly correlated with technological innovations, technology adoptions, user’s lifestyle, economic growth, etc. In regards to the significant importance of this research, it is repeatedly cited that approximately 20–40 percent of the entire energy consumption in developed countries (40 percent in Hong Kong, 37 percent in US, 39 percent in UK, & 31 percent in Japan) refers to the energy usage of buildings (Juan et al, 2010). Globally, this high level of energy consumption leads to environmental crisis including the climate change, global warming, lack of energy resources, difficulties in energy supplies, and ozone layer deterioration (Perez-Lombard et al, 2008). Hence, it is prudent to express the severe necessity for analyzing the energy consumption level of buildings and to innovate new solutions for achieving sustainability in built environments. Referring to the role of materials, the use of kenaf-fibres insulation boards is highly recommended for application in green buildings according to the study by Ardente et al (2008). Reduced energy consumption, and the consequent reduced energy costs, is one of the defining features of any green building. Estimates for the reduction in a green building’s energy use compared to a conventional code-compliant building range from 25% – 30% (based on LEED-certified buildings in the United States) to up to 35% – 50% (based on a similar study of green buildings in New Zealand) (Mwasha el al, 2011).

Building industry practitioners have begun to pay attention to controlling and correcting the environmental damage due to their activities. Architects, designers, engineers and others involved in the building process have a unique opportunity to reduce environmental impact through the implementation of sustainability objectives at the design development stage of a building project. Although new technologies such as Building Research Establishment Environmental Assessment Method (BREEAM), Building for Environmental and Economic Sustainability (BEES), Leadership in Energy and Environmental Design (LEED) etc., are constantly being developed and updated to complement current practices in creating sustainable structures, the common objective is that buildings are designed to reduce the overall impact of the built environment on human health and the natural environment.

4.1. Business Case for Energy Efficiency in Buildings

Buildings are the largest energy consumers in the world economy, accounting for over one-third of final energy use and approximately 30% of global carbon emissions. Although they are far less visible consumers of energy (and emitters of CO2) compared to similarly energy intensive sectors, such as transport or industry, buildings have a major role to play in any corporate strategy that aims to tackle climate change. This is why the World Business Council for Sustainable Development (WBCSD) has selected Energy Efficiency in Buildings (EEB) as one of the key business solutions needed to address the challenge of climate change. The Action2020 project has identified priority areas for business action that are based on scientific facts and social trends. A ‘Societal Must Have’ has been set for each priority area that business solutions should work towards achieving by 2020. The EEB 2.0 project will contribute to the climate change ‘Must-Have’. This says that in order to limit global temperature rise to 2°C above preindustrial levels, the energy and industry systems should undertake structural transformation to ensure that emissions do not exceed one trillion tonnes of carbon. Achieving this goal of limiting global temperature rise to 2°C would require a contribution from the buildings sector of approx. 80% reduction in total CO2 emissions by 2050 compared to today’s’ level (IEA). The EEB 2.0 project will work with member companies and external partners to dramatically reduce the energy consumption of buildings to help achieve this required contribution. The energy efficiency measures are driven not only by environmental concerns but also business ones. All the changes have made good business sense.

4.2. Imperative of Energy Efficiency in Emissions Reduction

Between now and 2030, energy efficiency can reduce the global cost of limiting warming to 2°C programme by up to $2.8 trillion in comparison to a more energy-intensive pathway. A new report ‘How Energy Efficiency Cuts Costs for a 2°C Future’ funded by Climate-Works and the research by a consortium of groups led by Fraunhofer ISI, analyses how energy efficiency policies and programs in Brazil, China, Europe, India, Mexico and the US can reduce the cost of economy-wide decarbonization by up to $250 billion per year for these regions, with no net cost to society through 2030. The potential annual savings of the energy-efficiency pathway vary from nation to nation. Annual savings range from 0.1 to 0.4 percent of annual GDP and are not sensitive to macroeconomic shifts or to changes in fuel price. In addition, the economic benefits of energy efficiency can help eliminate energy poverty. Recent research by the World Bank shows that the world can achieve universal access to electricity through investments of between $40 billion and $100 billion annually. The $250 billion saved in the regions studied could help finance this critical goal. China, Brazil and Mexico have already begun the process of ‘leapfrogging’ toward less energy-intense economies and are currently realizing avoided lock-in costs and related economic benefits. As part of the global commitment to limit warming to 2°C, building codes and retrofits in the US could also save roughly $20 billion annually, compared to other emissions reduction pathways.

4.3. The Implications of Sustainable Energy Performance

Recent scholarly studies have shown the implications of sustainable energy performances for green buildings and accordingly, the concept of zero energy building (ZEB) has been developed to ensure considerable reduction of energy consumption, gas emissions and the respective environmental impacts. ZEB is not a conceptual prototype but it is becoming a substantial basis of sustainable energy determinants (Marszal et al, 2011). With reference to US Energy Independence and Security Act of 2007 (EISA, 2007), half of the entire commercial buildings in US must be in comply with the standards of ZEB by 2040 while it will applicable to the entire commercial buildings in US by 2050 (Crawley et al, 2008). Referring to the European Energy Performance of Buildings (EPBD), as of 2018, the respective buildings owned by public authorities or the buildings used by public sectors must be in line with ZEB standards while from 2020 it will be applicable to all new buildings (Crawley et al, 2008). The aforementioned targets represent the critical necessity to consider the zero energy criteria for ensuring enhanced energy performances of buildings. In order to provide an explicit comparison between the zero energy buildings and the other types, the developed graph as shown in Figure 4 confirms the significant difference between the respective types (OJEU, 2010). While acknowledging the effectiveness of low energy buildings, the study represents that it is essential for governmental sectors and policy makers to consider the ZEB concept for the future energy targets of cities developments (Hernandez & Kenny, 2010)

Figure 4 Comparison between Different Types of Energy Buildings Source Hernandez & Kenny 2010
Figure 4 Comparison between Different Types of Energy Buildings Source Hernandez & Kenny 2010

 

 

 

 

 

 

5.0. Green Building Approaches and Techniques of Energy Conservation

Green building emphasizes the importance of environmentally friendly building techniques, which obviously includes energy efficient construction. Green building is essentially an umbrella that encompasses any energy efficient building method or practice and everything discussed in this chapter is a component of the green building approach. Green buildings have a significant impact upon energy use, both in terms of the building envelope as well as building systems and infrastructure. As a result, the Green Building Technology working group has taken on the effort to identify ways to encourage energy conservation, implement green construction practices, suggest and identify potential funding opportunities, encourage “best practices”, and provide guidance for businesses and the community-at-large regarding green and sustainable design opportunities. One of the major objectives of designing sustainable Green building is to create sustainable building policies that promote green building practices and energy efficiency for new construction as well as the retrofitting of existing building structures. This can lead to substantial savings in both the short and long-term. With specific reference to Energy conservation in green buildings the broad approaches and techniques of energy conservation may be adopted:

– Zero net energy goals, based on intermittent occupancy patterns
– Reduced energy load and renewable energy sources for heating & cooling
– High-performance building envelope
– Cool day-lighting and advanced lighting controls
– Cut-off exterior lighting fixtures to eliminate glare and light pollution
– High-performance mechanical systems
– Fundamental building commissioning for optimal system performance
– Reduced site disturbance at building, site access roads, parking and utilities to reduce erosion
– Panelized construction to reduce construction waste
– On-site construction waste management, with 95% recycled and diverted from landfill
– Operable windows for light, views and ventilation
– Physically-isolated and separately-ventilated janitor and copier rooms for indoor air quality
– Environmentally-responsible building materials and construction methods
– Water-conserving fixtures and landscaping

5.1. Sustainable Implementation: A Framework of Strategies and Methods

In order to achieve a sustainable future in the building industry, Asif et al. (2007) suggested adoption of multi-disciplinary approach covering a number of features such as: energy saving, improved use of materials, material waste minimization, pollution and emissions control etc. There are many ways in which the current nature of building activity can be controlled and improved to make it less environmentally damaging, without reducing the useful output of building activities. To create a competitive advantage using environment-friendly construction practices, the whole life-cycle of buildings should, therefore, be the context under which these practices are carried out. A review of literature has identified three general objectives which should shape the framework for implementing sustainable building design and construction (Figure 5), while keeping in mind the principles of sustainability issues (social, environmental and economic) identified previously. These objectives are:

1. Resource conservation
2. Cost efficiency and
3. Design for Human Adaptation

Figure 5 Framework for Implementing Sustainability in Building construction
Figure 5 Framework for Implementing Sustainability in Building construction

 

 

 

 

 

 

5.2. Suitable Design Process

Building a green building is not just a matter of assembling a collection of the latest green technologies or materials. Rather, it is a process in which every element of the design is first optimized and then the impact and interrelationship of various different elements and systems within the building and site are re-evaluated, integrated, and optimized as part of a whole building solution. For example, interrelationships between the building site, site features, the path of the sun, and the location and orientation of the building and elements such as windows and external shading devices have a significant impact on the quality and effectiveness of natural day lighting. These elements also affect direct solar loads and overall energy performance for the life of the building. Without considering these issues early in the design process, the design is not fully optimized and the result is likely to be a very inefficient building. This same emphasis on integrated and optimized design is inherent in nearly every aspect of the building from site planning and use of on-site storm water management strategies to envelope design and detailing and provisions for natural ventilation of the building. This integrated design process mandates that all of the design professionals work cooperatively towards common goals from day one. Basic Elements of a Green Building Project The following pages summarize key principles, strategies and technologies which are associated with the five major elements of green building design which are: Sustainable Site Design; Water Conservation and Quality; Energy and Environment; Indoor Environmental Quality; and Conservation of Materials and Resources.

5.3. Sustainable Site Design
Key Principles

Minimize urban sprawl and needless destruction of valuable land, habitat and green space, which results from inefficient low-density development. Encourage higher density urban development, urban re-development and urban renewal, and Brownfield development as a means to preserve valuable green space.

Preserve key environmental assets through careful examination of each site. Engage in a design and construction process that minimizes site disturbance and which values, preserves and actually restores or regenerates valuable habitat, green space and associated eco-systems that are vital to sustaining life.

Key Strategies and Technologies:

The Key Strategies and Technologies employed with reference to Sustainable Site Designs of Green building may include the following:

– Make more efficient use of space in existing occupied buildings, renovate and re-use existing vacant buildings, sites, and associated infrastructure and consider re-development of Brownfield sites.
– When new development is unavoidable, steer clear of sites that play a key role in the local or regional ecosystem. Identify and protect valuable Greenfield and wetland sites from development.
– Evaluate each site in terms of the location and orientation of buildings and improvements in order to optimize the use of passive solar energy, natural day lighting, and natural breezes and ventilation.
– Make best use of existing mass transit systems and make buildings and sites pedestrian and bike friendly, including provisions for safe storage of bicycles
– Help reduce the urban heat island effect by reducing the building and site development footprint, maximizing the use of pervious surfaces, and using light colored roofs, paving, and walkways. Provide natural shading of buildings and paved areas with trees and other landscape features.
– Reduce impervious areas by carefully evaluating parking and roadway design. Pursue variances or waivers where local ordinances may unintentionally result in the over-design of roadways or parking.
– Optimize the use of on-site storm water treatment and ground water recharge. Minimize the boundaries of the construction area, avoid needless compaction of existing topsoil, and provide effective sedimentation and silt control during all phases of site development and construction.
– Use landscape design to preserve and restore the region’s natural habitat and heritage while emphasizing the use of indigenous, hardy, drought resistant trees, shrubs, plants and turf.
– Help reduce night-time light pollution by avoiding over-illumination of the site and use low cut-off exterior lighting fixtures which direct light downward, not upward and outward.

Figure 6 The Schlitz Audubon Nature Center has a 10 kW Photovoltaic Solar Power System
Figure 6 The Schlitz Audubon Nature Center has a 10 kW Photovoltaic Solar Power System

 

 

 

 

 

 

5.4. Design Strategies: Energy Efficiency
Key Principles

– Building energy efficiency codes
– Building envelope, such as:
– HK-OTTV standard
– Overall thermal transfer value (OTTV)
– Codes of Practice for building services systems
– HVAC, lighting, electrical, lifts & escalators
– Performance-based building energy code
– Become mandatory in 2011 in Hong Kong, under the Buildings Energy Efficiency Ordinance

Design Strategies for Maximising Energy Efficiency:

– Minimise thermal loads & energy requirements
– e.g. by reducing heat gains from equipment
– Optimise window design & fabric thermal storage
– Integrate architectural & engineering design
– Promote efficiency in building services systems
– Use of heat recovery & free cooling methods
– Energy efficient lighting design & control
– High-efficiency mechanical & electrical systems
– Adopt total energy approach (e.g. district cooling, combined heat & power)

Promote passive design and natural ventilation

– e.g. bioclimatic buildings, passive cooling/heating
– Adopt energy efficient building services systems
– Lighting, air-conditioning, electrical, lifts
– Needs to study thermal & energy performance
– e.g. by computer simulation or energy audit
– Must also ensure efficient operation and management of the building
– User education & awareness, good housekeeping

5.5. Design Strategies: Renewable Energy

– Energy that occurs naturally and repeatedly on earth and can be harnessed for human benefit, e.g. solar, wind and biomass
– Common applications
– Solar hot water
– Solar photovoltaic
– Wind energy
– Geothermal
– Small hydros

5.6. Renewable in situ Energy Systems in Green Building: Case Studies

The following two illustrated Case studies are presented below to show the effective uses of renewable forms of energy in Green buildings in 2 different lead centres.

Case Study 1: Schlitz Audubon Nature Center

Solar Photovoltaic System: Geothermal HVAC, natural ventilation and day-lighting LEED-NC

Gold Building Name: Dorothy K. Vallier Environmental Learning Center Building
Location: 1111 E. Brown Deer Road, Milwaukee, WI
Project Size: 30,000 SF
Building Type(s): Education
Project Type: New Construction
Total Building Costs: $5.6 million
Owner: Schlitz Audubon Nature Center
Building Architect/Project Team: Architect: Kubala Washatko Architects, Inc.
Contractor: Jansen Group Engineering: Harwood Engineering Project

The Dorothy K. Vallier Environmental Learning Center is located at the Schlitz Audubon Nature Center, a privately funded, 183 acre nonprofit nature preserve dedicated to environmental education and land stewardship. Awarded LEED Gold certification, the Center provides space for classrooms, an auditorium, exhibits, a nature-focused preschool and a nature store. The Schlitz Audubon Nature Center has a 10 kW photovoltaic solar power system, donated by We Energies. This system provides between 10 percent and 20 percent of the Center’s electricity needs annually. A Geo-Exchange geothermal heat system that uses 90 groundwater wells provides heating and cooling for the Center. Additional design techniques and green products and materials used include: thermal massing, roof overhangs, passive solar design, natural ventilation, low flow plumbing and waterless urinals, site harvested lumber, reused materials and low VOC finishes. Focus on Energy’s New Construction Program awarded the Center with at $10,000 grant to study and incorporate these energy efficient features into its design.

Case study 2 onwards will feature in the next edition of the Masterbuilder Magazine.

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