What is Green Technology?

Environmental technology , green technology or clean technology is the application of one or more of environmental science, green chemistry, environmental monitoring and electronic devices to monitor, model and conserve the natural environment and resources, and to curb the negative impacts of human involvement.

It includes:

• Renewable energy• Recycling• Water purification• Air purification• Energy conservation• Alternative and clean power• Solid waste management

Green Building• Green building (also known as green

construction or sustainable building) refers to a structure and using process that is environmentally responsible and resource-efficient throughout a building's life-cycle: from siting to design, construction, operation, maintenance, renovation, and demolition.

• This requires close cooperation of the design team, the architects, the engineers, and the client at all project stages. The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort.

m

Goals of green

building

Life cycle assessment (LCA)

Siting and structure design efficiency

Energy efficiency

Water efficiency Materials efficiency

maintenance

Waste reduction

Life Cycle Assessment (LCA)A life cycle assessment (LCA) can help avoid a narrow outlook on environmental, social and economic concerns by assessing a full range of impacts associated with all cradle-to-grave stages of a process: from extraction of raw materials through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling. Impacts taken into account include (among others) embodied energy, global warming potential, resource use, air pollution, water pollution, and waste

Four main phases

• Goal and scope• Life cycle inventory• Life cycle impact assessment• Interpretation

Goal and scope• A starts with an explicit statement of the goal and scope of the study,

which sets out the context of the study and explains how and to whom the results are to be communicated. This is a key step and the ISO standards require that the goal and scope of an LCA be clearly defined and consistent with the intended application. The goal and scope document therefore includes technical details that guide subsequent work.

Life cycle inventory

• Life Cycle Inventory (LCI) analysis involves creating an inventory of flows from and to nature for a product system. Inventory flows include inputs of water, energy, and raw materials, and releases to air, land, and water. To develop the inventory, a flow model of the technical system is constructed using data on inputs and outputs. The flow model is typically illustrated with a flow chart that includes the activities that are going to be assessed in the relevant supply chain and gives a clear picture of the technical system boundaries. The input and output data needed for the construction of the model are collected for all activities within the system boundary, including from the supply chain (referred to as inputs from the techno-sphere).

Life cycle impact assessment

• Inventory analysis is followed by impact assessment. This phase of LCA is aimed at evaluating the significance of potential environmental impacts based on the LCI flow results. Classical life cycle impact assessment (LCIA) consists of the following mandatory elements:

1.selection of impact categories, category indicators, and characterization models; 2.the classification stage, where the inventory parameters are sorted and assigned to specific impact categories; and 3.impact measurement, where the categorized LCI flows are characterized, using one of many possible LCIA methodologies, into common equivalence units that are then summed to provide an overall impact category total.

Interpretation• Life Cycle Interpretation is a systematic technique to identify,

quantify, check, and evaluate information from the results of the life cycle inventory and/or the life cycle impact assessment. The results from the inventory analysis and impact assessment are summarized during the interpretation phase. The outcome of the interpretation phase is a set of conclusions and recommendations for the study. According to ISO 14040:2006, the interpretation should include:

1.identification of significant issues based on the results of the LCI and LCIA phases of an LCA;2.evaluation of the study considering completeness, sensitivity and consistency checks; and3.conclusions, limitations and recommendations.

Siting and structure design efficiency

• The foundation of any construction project is rooted in the concept and design stages. The concept stage, in fact, is one of the major steps in a project life cycle, as it has the largest impact on cost and performance.

• In designing environmentally optimal buildings, the objective is to minimize the total environmental impact associated with all life-cycle stages of the building project.

• However, building as a process is not as streamlined as an industrial process, and varies from one building to the other, never repeating itself identically.

• In addition, buildings are much more complex products, composed of a multitude of materials and components each constituting various design variables to be decided at the design stage. A variation of every design variable may affect the environment during all the building's relevant life-cycle stages.

Sustainable design principles• While the practical application varies among disciplines, some common principles are as follows:• Low-impact materials: choose non-toxic, sustainably produced or recycled materials which require little energy to

process• Energy efficiency: use manufacturing processes and produce products which require less energy• Emotionally Durable Design: reducing consumption and waste of resources by increasing the durability of

relationships between people and products, through design• Design for reuse and recycling: "Products, processes, and systems should be designed for performance in a

commercial 'afterlife'."• Design impact measures for total carbon footprint and life-cycle assessment for any resource used are increasingly

required and available. Many are complex, but some give quick and accurate whole-earth estimates of impacts. One measure estimates any spending as consuming an average economic share of global energy use of 8,000 BTU (8,400 kJ) per dollar and producing CO2 at the average rate of 0.57 kg of CO2 per dollar (1995 dollars US) from DOE figures.

• Sustainable design standards and project design guides are also increasingly available and are vigorously being developed by a wide array of private organizations and individuals. There is also a large body of new methods emerging from the rapid development of what has become known as 'sustainability science' promoted by a wide variety of educational and governmental institutions.

• Biomimicry: "redesigning industrial systems on biological lines ... enabling the constant reuse of materials in continuous closed cycles..."

• Service substitution: shifting the mode of consumption from personal ownership of products to provision of services which provide similar functions, e.g., from a private automobile to a carsharing service. Such a system promotes minimal resource use per unit of consumption (e.g., per trip driven).

• Renewability: materials should come from nearby (local or bioregional), sustainably managed renewable sources that can be composted when their usefulness has been exhausted.

• Robust eco-design: robust design principles are applied to the design of a pollution sources).

Energy efficiency

• Green Energy is energy that can be extracted, generated, and/or consumed without any significant negative impact to the environment. The planet has a natural capability to recover which means pollution that does not go beyond that capability can still be termed green.

• Green power is a subset of renewable energy and represents those renewable energy resources and technologies that provide the highest environmental benefit.

• In several countries with common carrier arrangements, electricity retailing arrangements make it possible for consumers to purchase green electricity (renewable electricity) from either their utility or a green power provider.

• When energy is purchased from the electricity network, the power reaching the consumer will not necessarily be generated from green energy sources. The local utility company, electric company, or state power pool buys their electricity from electricity producers who may be generating from fossil fuel, nuclear or renewable energy sources. In many countries green energy currently provides a very small amount of electricity, generally contributing less than 2 to 5% to the overall pool.

• By participating in a green energy program a consumer may be having an effect on the energy sources used and ultimately might be helping to promote and expand the use of green energy. They are also making a statement to policy makers that they are willing to pay a price premium to support renewable energy. Green energy consumers either obligate the utility companies to increase the amount of green energy that they purchase from the pool

GREEN PRICING

• Some power companies provide an optional service, called green pricing, that allows customers to pay a small premium in exchange for electricity generated from clean, renewable ("green") energy sources. The premium covers the increased costs incurred by the power provider (i.e., electric utility) when adding renewable energy to its power generation mix.

GREEN CERTIFICATES• Buying green certificates allows you to contribute to the

generation of clean, renewable power even if you can't buy clean power from your power provider (i.e., electric utility) or from a clean power generator on the competitive market.

• An increasing number of clean power generators are now separating the power that they sell to power providers from the environmental attributes associated with that power. These environmental attributes, called green certificates (also known as "green tags," "renewable energy certificates," or "tradable renewable certificates"), are then sold to companies and individuals who want to help increase the amount of clean power entering our nation's electricity supply.

• By separating the environmental attributes from the power, clean power generators are able to sell the electricity they produce to power providers at a competitive market value. The additional revenue generated by the sale of the green certificates covers the above-market costs associated with producing power made from renewable energy sources. This extra revenue also encourages the development of additional renewable energy projects.

Materials Efficency• Building materials typically considered to be

'green' include lumber from forests that have been certified to a third-party forest standard, rapidly renewable plant materials like bamboo and straw, dimension stone, recycled stone, recycled metal (see: copper sustainability and recyclability), and other products that are non-toxic, reusable, renewable, and/or recyclable (e.g., Trass, Linoleum, sheep wool, panels made from paper flakes, compressed earth block, adobe, baked earth, rammed earth, clay, vermiculite, flax linen, sisal, seagrass, cork, expanded clay grains, coconut, wood fibre plates, calcium sand stone, concrete (high and ultra high performance, roman self-healing concrete), etc.

THE FRAMING AND BUILDING STRUCTURE

• • Wood — Two types of wood are gaining traction among green builders — engineered lumber and wood certified by the Forest Stewardship Council (FSC). Engineered wood is very common on both green and conventional homes. It uses wood scraps and smaller trees to produce framing that’s stronger than traditional sawn logs. Engineered wood allows the builder to use less wood per structure and make use of wood scraps that would otherwise go to waste. Where conventional sawn timbers are used, some green builders use wood that bears FSC approval, meaning wood harvested from a managed forest.

• • Structural insulated panels (SIPS) — SIPS are large panels (4' x 8' up to 24' x 8') typically constructed at a factory. They are composed of foam insulation sandwiched between two sheets of oriented strand board (OSB). You can consider SIPS green because of their superior insulation and air-sealing qualities, but they often must be set in place with a crane. SIPS construction is typically slightly more expensive than conventionally built structures.

Interior finish• Green builders and designers typically try to replace the more

common synthetic materials used inside the structure with lower-impact natural materials.

• Natural clay plaster — Natural clay plasters are a green alternative to the more common gypsum-based plasters.

• Low/no-VOC (volatile organic compound) paints, stains, and coatings — Paints and stains are a common source of indoor air-quality issues due to the amount of harmful VOCs needed to keep them in a usable liquid form. VOCs spur the quick evaporation of liquids in paint to leave behind a solid film of color. Many manufacturers are now offering low- or no-VOC alternatives to address this environmental concern.

• Natural fiber flooring — Whatever type of flooring is desired, there are green alternatives. Rugs and carpets are available in natural materials such as wool and cotton, while wood and other solid alternatives such as bamboo and cork offer high durability and/or sustainable harvesting methods.

• •Paperless drywall — Paperless drywall helps save on deforestation by eliminating the paper surface manufactured from trees.

Heating and conditioning• The proper orientation of a building with respect to the sun and other

design details can contribute significantly to minimizing the heating and cooling needs of a building. There are also nonconventional HVAC systems that can play a significant role in using less energy in any structure.

• Geothermal — Heat pumps can provide heating and cooling to a building using a fraction of the energy of a conventional system. They work very much like a refrigerator — by using a compressor, evaporator, and condenser, heat can be moved. Heat pumps use the earth, ground water, or even the air as a source of heat, or a place to remove it, depending on the season.• Solar hot water — Solar water heating has been commercially available for decades for domestic hot water needs, but these systems can be used as the primary source of space heating as well when coupled with radiant flooring. By using radiant rather than convective heat transfer, the system can heat water to a lower temperature, which works very well with solar hot water systems.• Focus on high efficiency and proper sizing — Using the most efficient equipment available not only conserves energy but saves money as well. By properly matching the system to the building, you can avoid purchasing an unnecessarily large and expensive system.

Insulation• Insulation is critical for any building. Whether the builder is trying to keep the heat out or in, the amount of

insulation will indicate how resistant a building is to losing energy.

• Fiberglass — Builders generally don’t consider fiberglass insulation a green material because it typically contains a toxic binding agent and is very energy-intensive to make. However, superinsulating a structure beyond building-code requirements is a fundamental principle of green building. Many green builders take advantage of the low cost and ease of installation to superinsulate and save money that they can use for other green features.

• Cellulose — Made from recycled paper, cellulose is the second most common insulation material and is considered a very green choice when used properly. Also, it is relatively inexpensive, with costs similar to fiberglass.

• Natural fiber (cotton, wool) — Cotton insulation is typically made from recycled cotton fibers formed into a batt, a preformed section of insulation sized to fit snugly in a framed cavity. Wool is an excellent insulator and a rapidly renewable resource. However, while it is commercially available, you can typically find it only in areas where wool is abundant.

• Polyurethane — Expanding spray-on polyurethane foams are quickly becoming very popular. They offer the highest insulation value for a given thickness and, because of their expansion during installation, are excellent at eliminating air leakage.

• Polystyrene and isocyanurate — These foams are typically installed as preformed sheets. Builders commonly use them to insulate below grade, such as beneath a slab, but also use them as exterior-mounted insulation in some applications.

Roofing• Keeping the weather out of a structure is not only key to making it a

comfortable environment but is also critical to making it last. Like the variety of choices for other building components, there are now numerous ways to cover a building. The color of the material can also have an impact. Light colors are preferable for all types of roofing, as they reflect more energy away from the structure and thus reduce the cooling load.

• Steel — Steel roofing (both panels and shingles) is an increasingly popular green choice because of its high recycled content and longevity.

• Slate/stone — These natural materials are excellent green choices but are very expensive due to both material and labor considerations. While mining companies typically mine and ship natural materials long distances, they have a very long life.

• Composites — Manufacturers often make composites from plastics and rubber, and they mimic the appearance of natural materials such as slate and wood. They have the advantage of being lighter than their natural counterparts. Composites are frequently made from recycled materials and so have a lower embodied energy than materials that must be mined.