Dr. A N Sarkar
Ex-Senior Professor (International Business) & Dean (Research), Asia-Pacific Institute of Management, New Delhi
Case Study 2: Wisconsin Energy Conservation Corporation
Solar photovoltaics, solar hot water heating and day-lighting LEED 2.1 Registered
Building Name: Wisconsin Energy Conservation Corporation Building
Location: Madison WI
Project Size: 34,500 SF
Building Type(s): Commercial Office
Project Type: New Construction
Total Building Costs: $5.4 million
Owner: Wisconsin Energy Conservation Corporation; non-profit corporation
Building Architect/Project Team: Architect: Eppstein Uhen Architects
Contractor: Vogel Brothers Building Co.
Commissioning: Sustainable Engineering Solar: Seventh Generation Energy Systems Project
Wisconsin Energy Conservation Corporation (WECC) champions innovative energy initiatives that deliver short and long-term economic and environmental benefits to consumers, businesses and policy makers. WECC is making a commitment to sustainable design and is striving for LEED Gold certification1. WECC’s building will be a showcase for energy efficiency, affordability, renewable energy and sustainable design. The 19 kW solar energy systems are composed of four pole-mounted solar arrays and a large solar array on the roof of the two-story building. These were engineered and installed by Seventh Generation Energy partnering with Conergy. The Suntech panels are expected to supply 23,000 kWh per year, or 14% of the building’s annual energy needs2. A solar water heating system, donated by Hot Water Products of Milwaukee and also installed by Seventh Generation Energy Systems, will provide approximately 40% of the building’s domestic hot water needs Figure 7.
The sun is the most reliable, renewable and clean energy source we have, so it’s amazing to me that more people don’t use solar power. Not only can you use passive solar design to heat and cool your house more efficiently, but you can generate your own heat and electricity using photovoltaics. Typical barriers to entry in the past have included high costs, low efficiency, and plain old reticence to stick bulky and ugly looking things like solar panels atop our roofs. Fortunately, there have been massive improvements in photovoltaic technology in the past few years, and solar power is now accessible to pretty much everyone. Photovoltaic systems have become cheaper, more efficient, and most importantly, a lot better looking in the past few years. Say goodbye to the ugly awkward roof-mounted panels of the 70s – today’s photovoltaics are often incorporated directly into the materials you use to clad your house. There are now solar roofing shingles, solar side-cladding, and even solar-powered glass windows.
6.0. Integrated Building Design of Green Building for Energy Conservation
An integrated building design of Green building meant for effective energy conservation entails a systematic linkage with sustainable urban design system; as conceived in Figure 8 below.
Today, it is possible to apply green materials and advanced technologies in the building design projects to consume less energy. Building design for green buildings involves many professionals across different areas. Many factors need to be taken into account, including climate, building share, comfort levels, material and systems, and health. Figure 9 illustrates the interrelationships among these four main influences on energy efficiency and the key energy consumers. It shows that energy use are affected by many factors, for example, four factors including design, building envelope, equipment and infrastructure all have impacts on the energy needs for heating, ventilation and air conditioning (HVAC). HVAC systems consume the most
Energy – accounting for 37% of total energy use in buildings. Integrated building design requires all participants including owners, architects, engineers and others involve at the early phase of the building project. Building energy performance depends not only on the performance of an individual technology but also on how these perform as an integrated system. The building envelope is the starting point of energy efficient buildings, interacting with HAVC system and lighting, while design will bring together all elements influences on energy efficiency (WBSCD, 2009).
An integrated design process involves all relevant participants from the start. Integration of both passive and active measures is crucial to effective building design and construction. Figure 9 indicates that integrated design approaches will achieve the best performance in terms of energy saving. Integrated design approaches could reduce energy use by as much as 72% (WBSCD, 2009). But projects could be more expensive than individual solutions and thus require financial support and incentives from government regulation to reinforce this holistic approach.
6.1. “Zero-energy” or “Zero-carbon” New Buildings
“Zero-energy” building, “net zero energy” building or “Zero-carbon” building is a general term applied to a building’s use with zero net energy consumption and zero carbon emissions annually. As pointed out before, much building energy is wasted because of poor design, inadequate technology and inappropriate practices. The concept of “Zero-energy” building has been introduced recently to focus on energy consumption. The carbon emissions generated from on-site or off-site fossil fuel uses are balanced by the amount of on-site renewable energy production, so it is also called as “zero-carbon” building. “Zero-energy” buildings are usually built with significant energy-saving features such as building orientation, solar panel roofs and super insulated HAVC system. The goal of green building is to increase the efficiency of resource use (including energy, water and materials) and reduce the building’s negative impacts on the environment during the building’s lifecycle. “Zero energy” buildings achieve one key green building goal of reducing energy use and greenhouse gas emissions. They may or may not be considered “green” in all areas such as reducing waste etc, but they reduce ecological impact. Meanwhile, many green building certification programs worldwide do not require a building to have net zero energy use, only require a building to reduce energy use below the standard limit by law.
The UK government made its commitment to be the first in the world to require zero carbon homes as a law from 2016. Energy efficiency standard will be required of new homes. For example, Barratt, one of leading house builder plans to build 195 zero-carbon homes on a disused hospital site near Bristol (Fickling, 2009). The labour government invested an extra £3.2 million to boost long-term research into building design and energy efficiency. The research tests new technologies and material to provide valuable evidence for future standards and how to drive down energy bills. To encourage zero carbon homes, an exemption from stamp duty land tax is planned. In Wales, the plan of zero carbon building as the standard for all new homes is to be met earlier in 2011. Some cases of green buildings are listed as followed:
Case study 1: Senedd,-the green building for the National Assembly for Wales, UK
The home of the national Assembly for Wales, the Senedd building, costs some £67 million and was completed in 2006. It has won important award for sustainable construction to recognize the “green” principles within its design (BBC, 2009). It has low environmental impact achieved through the use of renewable and low energy solutions to generate heat and maintain the building. For example, the roof plane around the top building turns down to form a funnel into the debating chamber, allowing ventilation and natural light. Natural ventilation is used in nearly all areas of the building. Offices do not have air conditioning as outlets in the floor push cool air into the rooms. The earth heat exchange system uses the earth as both a heat source and a heat sink. A biomass boiler fuelled by local wood chips helps to reduce carbon-di-oxide emission. Rainwater is collected on to roof and used to supply the toilets and window washing.
Case Study 2: Sustainability Assessment of Green City/
Buildings of MALMÖ, SWEDEN
The Bo01 high-density mixed-use development in Malmö, Sweden, was based on innovative planning procedures and products. A very broad definition of sustainability required new approaches in collaboration by the city, developers, planners, and designers. The outcomes of the project included outstanding aesthetics in the plan and the individual elements, as well as spaces that foster social interactions at the city, neighborhood, and block scales. A density of 26 residential dwelling units per gross acre balances the 50% open space dedication. Comprehensive planning for energy, water, and waste systems resulted in significant improvements, especially in energy production (100% is from renewable sources) and solid waste management. A wind turbine provides most of the electricity while a district-wide system supplied by a geothermal storage network provides almost all of the heating and cooling resources. Measures taken to replace and sequester toxic soils on the Brownfield site were coupled with the concept for the storm-water system. The surface storm-water system provides a model of effective design, due in part to high permeability requirements. While admirable by American standards, the energy efficiency of most of the 70 buildings failed to achieve the project goals. Similarly, on-site biodiversity measures achieved mixed results. Sweden’s first stage housing estate of the Western Harbour was developed in 2001. The houses are designed as sustainable buildings with well-insulated and high efficiency electrical equipment to minimise heat and electricity consumption, using 100% renewable energy supply. The waste management system is designed to use waste and sewage as an energy source. Each unit is designed to use no more than 105kW/m2/year, including household electricity.
Case study 3: Googleplex, California, USA
In the US, zero energy building research is supported by the US Department of Energy (DOE) Building America Program. DOE plans to invest a $40 million fund during 2008-2012 to develop net-zero-energy homes that consume 50% to 70% less energy than conventional homes (DOE, 2007). Googleplex, Google’s headquarters in Mountain View, California is an example of a zero-energy commercial building with a 1.6 megawatt photovoltaic campus-wide renewable power system. Google has developed advanced technology for major reductions in computer-server energy consumption which is becoming a part of zero-energy commercial building design.
Case study 4: Pearl River Tower, Guangzhou, China
In China, one example of zero-energy office building is the 71-story Pearl River Tower, designed by Skidmore, Owings & Merrill LLP (SOM) in China. It will be used as headquarters of Guangdong Tobacco Corporation and became as one of the most energy-efficient skyscrapers in the world when it is completed in 2010. It uses both modest energy efficiency, and a big distributed renewable energy generation from both solar and wind. The 2.3-million square-foot tower redefines sustainable design by incorporating the latest sustainable technology and engineering advancements, including wind turbines, solar panels, double skin curtain wall, chilled ceiling system, under floor ventilation air, and daylight harvesting. The tower has received economic support from government subsidies that support the application of renewable energy technologies.
6.2. Building Design to Facilitate Energy Conservation
One of the primary ways to improve energy conservation in buildings is to use an energy audit. An energy audit is an inspection and analysis of energy use and flows for energy conservation in a building, processor system to reduce the amount of energy input into the system without negatively affecting the output(s). This is normally accomplished by trained professionals and can be part of some of the national programs discussed above. In addition, recent development of smart-phone apps enable homeowners to complete relatively sophisticated energy audits themselves. Building technologies and smart meters can allow energy users, business and residential, to see graphically the impact their energy use can have in their workplace or homes. Advanced real-time energy metering is able to help people save energy by their actions. The more energy we conserve, the fewer new sources of supply our province will need in the future. Now is the time for action, innovation and personal commitment. This strategy supports government’s goal to reduce greenhouse gas emissions by 33 per cent from 2007 levels by 2020 as well as electricity self-sufficiency by 2016. More than four million British Columbians use 315 million square metres of floor space. The amount of energy we use has grown with our population. But we can reduce our energy use by making new homes energy efficient from the start, incorporating renewable energy systems and conservation features into existing buildings, and lowering operating costs through careful planning and design.
6.3. Green Building Technology and Energy Conservation
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. While “recycle” may be a buzzword for an en¬vironmentally friendly way to manage waste, a more comprehensive approach to doing so is summarized by the “Three Rs” (Figure 10):
I. Reduce: Buy only what you need because a better way to reduce waste is by not creating it.
II. Reuse: If you have to acquire goods, try getting used ones or obtaining substitutes.
III. Recycle: When discarding your waste, find ways to recycle it instead of letting it go to landfill.
As a nation, we are generating more garbage and we don’t know what to do with it. Ineffective or irresponsible disposal of this waste can pollute the environment and pose a public health risk. We are running out of space in existing landfills. Citizens are discovering that there is no easy way to get rid of the garbage they once assumed could be buried or burned and forgotten. Current disposal methods threaten our health, safety, and environment, and pose additional indirect costs to society. Most industrial, commercial, and household waste is now being placed in landfills or surface impoundments. Waste treated in this manner may contaminate groundwater, rivers, and streams. When waste is burned, it releases hazardous gases into the air and leaves toxic residues in the form of ash. These hazardous waste byproducts find their way into humans and animals in one form or another.
8.4. Efficient Use and Conservation of Energy in Building
The main energy-using systems related to buildings are building structure elements (that is, the building envelope), heating, ventilation, and air conditioning equipment (HVAC), and energy-consuming devices and appliances, including lighting (Figure 11). The efficiency of all these energy systems can be improved by implementing various measures and by switching to energy-efficient equipment. Another way to improve energy efficiency is by implementing load management technologies. The following sections summarize the main energy efficiency measures for buildings. More detailed treatments for lighting, building envelope, and HVAC systems may be seen in Figure 11.
8.4.1. Passive Solar Design for Innovative Heating System
Solar heating systems can be installed in all types of buildings. Using solar power to pre-heat outside air before it is allowed to enter a building can considerably reduce heating costs both in residential buildings and commercial constructions. Solar heating systems are especially efficient for large buildings such as hospitals, hangars, school and gyms, as well as multi-story residential buildings. To make solar electricity available on a large scale, scientists and engineers around the world have been trying to develop a low-cost solar cell for many years. Such cells must be very efficient and easy to manufacture, with a high yield. The vast majority of solar heating systems require the installation of solar walls. Such equipment can be installed on new or existing buildings. Solar walls require very little maintenance, feature no liquids or detachable parts other than the ventilators connected to the ventilation system. Moreover, solar walls can operate under cloudy conditions and at night time, even if their efficiency is much less. The ROI is two years due to the energy savings they produce.
A passive solar design consists of an assembly of primarily non-mechanically driven architectural components that convert solar energy into usable heat. In winter, heat gained through windows and walls when the sun is shining is stored in masonry and/or water for night-time release. In passive solar building design, windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design or climatic design because, unlike active solar heating systems, it doesn’t involve the use of mechanical and electrical devices.
The key to designing a passive solar building is to best take advantage of the local climate. Elements to be considered include window placement and glazing type, thermal insulation, thermal mass, and shading. Passive solar design techniques can be applied most easily to new buildings, but existing buildings can be retrofitted. In summer, roof overhangs and landscape features limit heat gain, and vents dissipate unwanted heat. An optimal solar design maximizes heat gain in the winter and minimizes heat gain in the summer and so minimizes the total cost of providing heating and cooling of a building during its lifetime. The assembly of components used in a passive solar design is site specific, varying with climate, building orientation, and building design. The following components are used in different combinations:
– Double-glazed, south-facing windows
– Masonry or water heat storage walls
– Sunspace or greenhouse
– Overhanging roof
– Earth berm
– Movable insulation (window blankets)
– Exhaust fans (occasionally).
High levels of weatherization are necessary in order for passive solar systems to be effective.
9.0. Green Building – Green Installations
9.1. Use of Electrical Panel
A surprising number of power companies offer the option to purchase green power, and many that don’t supply renewable energy directly offer credit schemes that effectively offset standard energy consumption by helping to fund progress towards more sustainable sources. Electrical panels can improve energy performance in a home and thereby contribute to sustainable development and the green building approach. In light of its weight in energy consumption, building energy use is a major concern. Innovative solutions now exist to compensate reactive energy and measure building consumption. The innovative offers brought out by the Legrand Group concern the whole electrical panel. Everything from the installation head, to custom equipment boxes is available. As the electrical panel is the core of the electrical installation, it is logical that it is active in the deployment of solutions that aim to support sustainable development.
9.2. Reactive Power Compensation
Reactive power causes more energy to be consumed and in the end contributes to increasing CO2 emissions into the atmosphere and to more costly electricity bills.
The conservation of natural resources and enhanced energy efficiency are the fundamental objectives of sustainable development and green building policies. Reactive power compensation can increase the energy efficiency of an installation. It is then possible to achieve a situation where only the active (useful) energy is carried, both on transport and distribution networks, and in customer networks.
The use of reactive energy compensation equipment is a major source of savings. Such equipment enables an immediate and significant reduction in energy consumption and CO2 emissions. The capacitor banks provide the reactive energy necessary for certain equipment to work (ballast, motors, etc.). They enable consumers to subscribe to a less expensive power supply contract with the utility supplier. Low Voltage and High Voltage capacitor banks are designed and sold by the Legrand group in France and around the world. They make a significant contribution to sustainable development. These capacitors compensate the installation’s reactive energy while reducing energy bills. In effect, they reduce the apparent power required by the installation by around 20%. This can avoid the replacement of a substation that has reached its power capacity or to settle for a subscription that is limited by technical conditions (many subscribers on a single transformer). Capacitors are used in industrial buildings and large commercial buildings. With the same subscription, they can eliminate the reactive energy bill, optimise the subscription and increase the installation yield. In a 1000 m² supermarket, savings can reach €1128 per year. The savings in CO2 amount to 1.6 tonnes a year and the cost is amortised in just 2 years.
9.3. Lighting Control System
The lighting control system represents a solution to reduce consumption in commercial applications and improve the global costs in terms of building maintenance. It includes ECO1 and ECO2 stand-alone sensors, the installation on BUS/SCS and stand-alone Radio/Zigbee sensors. This control system uses various lighting control solutions to make energy savings and ensure comfort of use. It is a genuine source of energy bill reductions and makes a valid contribution to sustainable development. The system can be used both in new buildings and renovations.
BUS/SCS sensors can be used individually or for centralised installations. Their deployment is simple and usually done in technical ceilings. These detectors and controls are by default configured intuitively. The settings are calculated either by the programming software or by customising them on the equipment, by touch controls or wireless configuration via the sensors. According to a calculation based on the EN 15 193 standard and for a 100 m² area with natural lighting, BUS/SCS variable controllers in technical ceilings can make substantial annual savings. For 100 m², the savings could reach €100/year on green/yellow rate and up to €160/year on blue rate, or 160 kg of CO2 equivalent/year of pollution-generating gases. BUS/SCS sensors therefore make an efficient contribution to the green building approach.
Stand-alone Radio/Zigbee sensors are generally used in addition to BUS/SCS devices. Such sensors are also used to independently control many different applications with individual controls or centralised control depending on the programming. The Office block equipment with its 230V Radio/Zigbee control will for example, control the office lighting and turn on / cut off PC power in parallel to the BUS/SCS. According to standard En 15 193 and with an ON/OFF lighting control, this type of detection can generate annual savings of up to €80/year at green/yellow rates and up to €130/year on blue rate. This represents 120 kg of CO2 equivalent per year. The BUS/SCS – Radio/Zigbee interface is used to connect a BUS/SCS installation and an additional Radio/Zigbee installation together
9.4. Heat Insulation for a Green Building: Eco-Insulation
In our climates, whether we build new buildings or undertake renovations, seeking the maximum possible reduction in heat loss (thermal efficiency) is one of the main points to take into account in the green building approach. This reduction in heating requirements, absolutely necessary in light of economic, demographic and environmental indicators, is achieved by a three-pronged approach – “sobriety, efficiency and renewable energies.” In relation to the current trend of increasing energy needs, this approach will enable us to reach the “factor 4” objectives (commitment by western governments to reduce their CO2 emissions by a factor of 4 by 2050), by acting on three levers in a precise order, which is implemented as follows in the construction industry:
– First of all sobriety: Through architectural design that will save space (to be built and heated), reduce heat-loss surfaces, capture and manage free sun heating in winter, protect from the sun in summer. This sobriety in design is backed up by sobriety in use, which is also a major factor in reducing consumption.
– Then efficiency: Through a building envelope that drastically reduced heat loss in winter and avoids over-heating in summer, which also makes use of the thermal properties of materials, with equipment suited to needs.
– Lastly and lastly only, the use of renewable energies: As an addition to heating and hot water systems.
The efficiency of the building envelope is depended on three factors: Fully insulated walls, limited gaps in insulation (thermal bridges) and limited parasite air passages. Full insulation is a result of the project design phase: while limiting thermal bridges depends on the choice of construction systems and airtight seals are instantly associated with the quality of deployment work.
9.5. Roof Insulation of Green Building
Roofs are extremely important components in the construction of a Green building. They help to control the air flows and humidity in a building and also insulate it from exterior temperatures. In most old buildings, the protective function of the roof did not include the thermal insulation role so to speak, which was done on the last floor level, the attic floor. They were referred to as cold roofs.
Today, it is rare that the two functions of protection and insulation are not merged in order to make the whole volume of space under the roof and inside the walls inhabitable. But this gain of space comes with a new role for the roof as an exterior separation. From a thermal management viewpoint, roofs are opaque walls which, for a given surface area, present both heat losses in winter and the risk of overheating in summer.
This tells us that it is the separation that must receive the highest level of insulation, both to prevent the loss of heat in winter and to prevent its entry in summer. Insulating the roof should therefore take into account not only the thickness of the insulation material, but also its density (transmission inertia) and all the thermal bridges and air leakage points. The massive use of wood in any construction approach for its mechanical properties has already helped to reduce thermal bridges due to its relatively low conductivity. To remedy the effects of transmission inertia on the roof, the first actions to take are in construction:
– A low-capture covering (plant roof)
– An air gap under the covering, sized for a real thermal draft, which depending on the gradient, may represent wide spaces (over 10 cm for a 30% gradient) and specific fittings for the entrances and exits of the air flow;
– A high-inertia interior cladding (ceiling).
The plant roof or green roof is a major ecological benefit for sustainable constructions. It brings together all the benefits of a sustainable construction. Installed on terraces or flattish roofs, a green roof is part of a sustainable development approach as it proposes natural building insulation. In the urban context, a green roof helps restore biodiversity. This solution also offers strong perspectives in terms of biological filtration and cleansing of rain water. It also captures rain water and limits rain water run-off in pipelines. Green roofs in an urban environment also help to reduce CO2 content in the air, while capturing the main culprits of pollution (atmospheric dust and pollen).
The Green Roof technique can also insulate the building naturally. The mix of earth and rooted plants on roofs produces an airtight and watertight roof but which can also resist wind and fire. For the past few years, the practice of creating green roofs is a de facto part of current sustainable construction practices, the architectural version of the sustainable development philosophy. Green roofs can in effect protect the insulating membranes from UV rays and solar thermal radiation. This natural protection means we can hope the insulating membrane may last from 30 to 50 years.
10.0. Energy Efficiency in Buildings: The Way Forward
The building stock includes residential, commercial, institutional, and public structures. Opportunities to minimize energy requirements through energy efficiency and passive renewable energy in buildings encompass building design, building materials, heating, cooling, lighting, and appliances. Commercial buildings include a wide variety of building types such as offices, hospitals, schools, police stations, places of worship, warehouses, hotels, libraries, shopping malls, etc (Figure 12). These different commercial activities all have unique energy needs but, as a whole, commercial buildings use more than half their energy for heating and lighting (EPRI- EM-4195).
In commercial buildings the most common fuel types used are electricity and natural gas. Occasionally commercial buildings also utilize another source of energy in the form of locally generated group or district energy in the form of heat and/or power. This is most applicable in situations where many buildings are located close to each other such as is in big cities, university campus, where it is more efficient to have a centralized heating and cooling system which distributes energy in the form of steam, hot water or chilled water to a number of buildings. A district system can reduce equipment and maintenance costs, as well as save energy, by virtue of the fact that it is more efficient and economic to centralize plant and distribution (National Renewable Energy Laboratory: http://www.nrel.gov).
10.1. Addressing the need to conserve Energy
Addressing the issue to minimize the effects of the present crises and future energy demands, the western and most developed countries who are considered responsible for the consumption of most of the world’s energy, reached to the conclusion on four main aspects for conserving energy resources and they are as follows (Kjeld Johnsen: Energy Conservation in the Built Environment; Session 1 & Session IV):
– Reducing energy consumption in buildings, by energy management and energy efficient measures;
– The urgent requirement for alternatives and renewable energy sources of lower price;
– The design of buildings for the attainment of thermal efficiency including better insulation;
– Conserving water, materials and energy sources.
In terms of energy conservation by alternative or renewable sources, solar energy and its applications tend to be more practical in terms of linking local generation (supply and demand) and hence are the most attractive for the future.
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