Sustainable engineering

Sustainable urban design and innovation: Photovoltaic ombrière SUDI is an autonomous and mobile station that replenishes energy for electric vehicles using solar energy.

Sustainable engineering is the process of designing or operating systems such that they use energy and resources sustainably, in other words, at a rate that does not compromise the natural environment, or the ability of future generations to meet their own needs.

Common engineering focuses

As an aspect of engineering disciplines

Every engineering discipline is engaged in sustainable design, employing numerous initiatives, especially life cycle analysis (LCA), pollution prevention, design for the environment (DfE), design for disassembly (DfD), and design for recycling (DfR). These are replacing or at least changing pollution control paradigms. For example, concept of a "cap and trade" has been tested and works well for some pollutants. This is a system where companies are allowed to place a "bubble" over a whole manufacturing complex or trade pollution credits with other companies in their industry instead of a "stack-by-stack" and "pipe-by-pipe" approach, i.e. the so-called "command and control" approach. Such policy and regulatory innovations call for some improved technology based approaches as well as better quality-based approaches, such as leveling out the pollutant loadings and using less expensive technologies to remove the first large bulk of pollutants, followed by higher operation and maintenance (O&M) technologies for the more difficult to treat stacks and pipes. But, the net effect can be a greater reduction of pollutant emissions and effluents than treating each stack or pipe as an independent entity. This is a foundation for most sustainable design approaches, i.e. conducting a life-cycle analysis, prioritizing the most important problems, and matching the technologies and operations to address them. The problems will vary by size (e.g. pollutant loading), difficulty in treating, and feasibility. The most intractable problems are often those that are small but very expensive and difficult to treat, i.e. less feasible. Of course, as with all paradigm shifts, expectations must be managed from both a technical and an operational perspective.[2] Historically, sustainability considerations have been approached by engineers as constraints on their designs. For example, hazardous substances generated by a manufacturing process were dealt with as a waste stream that must be contained and treated. The hazardous waste production had to be constrained by selecting certain manufacturing types, increasing waste handling facilities, and if these did not entirely do the job, limiting rates of production. Green engineering recognizes that these processes are often inefficient economically and environmentally, calling for a comprehensive, systematic life cycle approach. Green engineering attempts to achieve four goals:[3]

  1. Waste reduction;
  2. Materials management;
  3. Pollution prevention; and,
  4. Product enhancement.

Green engineering encompasses numerous ways to improve processes and products to make them more efficient from an environmental and sustainable standpoint. Every one of these approaches depends on viewing possible impacts in space and time. Architects consider the sense of place. Engineers view the site map as a set of fluxes across the boundary. The design must consider short and long-term impacts. Those impacts beyond the near-term are the province of sustainable design. The effects may not manifest themselves for decades. In the mid-twentieth century, designers specified the use of what are now known to be hazardous building materials, such as asbestos flooring, pipe wrap and shingles, lead paint and pipes, and even structural and mechanical systems that may have increased the exposure to molds and radon. Those decisions have led to risks to people inhabiting these buildings. It is easy in retrospect to criticize these decisions, but many were made for noble reasons, such as fire prevention and durability of materials. However, it does illustrate that seemingly small impacts when viewed through the prism of time can be amplified exponentially in their effects. Sustainable design requires a complete assessment of a design in place and time. Some impacts may not occur until centuries in the future. For example, the extent to which we decide to use nuclear power to generate electricity is a sustainable design decision. The radioactive wastes may have half-lives of hundreds of thousands of years. That is, it will take all these years for half of the radioactive isotopes to decay. Radioactive decay is the spontaneous transformation of one element into another. This occurs by irreversibly changing the number of protons in the nucleus. Thus, sustainable designs of such enterprises must consider highly uncertain futures. For example, even if we properly place warning signs about these hazardous wastes, we do not know if the English language will be understood. All four goals of green engineering mentioned above are supported by a long-term, life cycle point of view. A life cycle analysis is a holistic approach to consider the entirety of a product, process or activity, encompassing raw materials, manufacturing, transportation, distribution, use, maintenance, recycling, and final disposal. In other words, assessing its life cycle should yield a complete picture of the product. The first step in a life cycle assessment is to gather data on the flow of a material through an identifiable society. Once the quantities of various components of such a flow are known, the important functions and impacts of each step in the production, manufacture, use, and recovery/disposal are estimated. Thus, in sustainable design, engineers must optimize for variables that give the best performance in temporal frames.[3]

Accomplishments from 1992 to 2002

Sustainable housing

In 2013, the average annual electricity consumption for a U.S. residential utility customer was 10,908 kilowatt hours (kWh), an average of 909 kWh per month. Louisiana had the highest annual consumption at 15,270 kWh, and Hawaii had the lowest at 6,176 kWh.[4] Residential sector itself uses 18%[5] of the total energy generated and therefore, incorporating sustainable construction practices there can be significant reduction in this number. Basic Sustainable construction practices include :

  1. Sustainable Site and Location: One important element of green that is often overlooked happens to simply be where we choose to build. Avoiding inappropriate sites such as farmland and locating the site near existing infrastructure, like roads, sewers, stormwater systems and transit, allows builders to lessen negative impact on a home's surroundings.
  2. Water Conservation: Conserving water can be economically done by installing low-flow fixtures that often cost the same as less efficient models. Water can be saved in landscaping applications by simply choosing the proper plants.
  3. Materials: Green materials include many different options. Most often, people assume that "green" means recycled materials. Although that recycled materials represent one option, green materials also include reused materials, renewable materials like bamboo and cork, or materials local to your region. Remember, a green material does not have to cost more or be of lesser or higher quality. Most green products are comparable to their non-green counterparts.
  4. Energy Conservation: Probably the most important part of building green is energy conservation. By implementing passive design, structural insulated panels (SIPs), efficient lighting, and renewable energy like solar and geothermal, a home can benefit from reduced energy consumption or qualify as a net-zero energy home.
  5. Indoor Environmental Quality: The quality of the indoor environment plays a pivotal role in a person's health. In many cases, a much healthier environment can be created through avoiding hazardous materials found in paint, carpet, and other finishes. It is also important to have proper ventilation and ample day lighting.[6]

Savings

  1. Water Conservation: A newly constructed home can implement products with the WaterSense label at no additional costs and achieve a water savings of 20% when including the water heater savings and the water itself.
  2. Energy Conservation: Energy conservation is definitely the most intensive when it comes to cost premiums for implementation. However, it also has the largest potential for savings. Minimum savings can be achieved at no additional cost by pursuing passive design strategies. The next step up from passive design in the level of green (and ultimately the level of savings) would be implementing advanced building envelopematerials, like structural insulated panels (SIPs). SIPs can be installed for approximately $2 per linear foot of exterior wall. That equals a total premium of less than $500 for a typical one-story home, which will bring an energy savings of 50%. According to the DOE, the average annual energy expense for a single family home is $2,200. So SIPs can save up to $1,100 per year. To reach the savings associated with a net-zero energy home, renewable energy would have to be implemented on top of the other features. A geothermal energy system could achieve this goal with a cost premium of approximately $7 per square foot, while a photovoltaic system (solar) would require up to a $25,000 total premium.[6]

See also

References

  1. ↑ Huesemann, Michael H., and Joyce A. Huesemann (2011). Technofix: Why Technology Won’t Save Us or the Environment, Chapter 13, "The Design of Environmentally Sustainable and Appropriate Technologies", New Society Publishers, Gabriola Island, British Columbia, Canada, ISBN 0865717044, 464 pp.
  2. ↑ D. Vallero and C. Brasier (2008), Sustainable Design: The Science of Sustainability and Green Engineering. John Wiley and Sons, Inc., Hoboken, NJ, ISBN 0470130628.|url=https://books.google.com/books/about/Sustainable_Design.html?id=vrj5DIQ-7m8C%7C
  3. 1 2 D. Vallero and C. Brasier (2008), Sustainable Design: The Science of Sustainability and Green Engineering. John Wiley and Sons, Inc., Hoboken, NJ, ISBN 0470130628.
  4. ↑ "How much electricity does an American home use? - FAQ - U.S. Energy Information Administration (EIA)". www.eia.gov. Retrieved 2015-09-02.
  5. ↑ "How much energy is consumed in the world by each sector? - FAQ - U.S. Energy Information Administration (EIA)". www.eia.gov. Retrieved 2015-09-02.
  6. 1 2 AP, Michael Tolson MBA, LEED. "Green Homes vs Traditional Homes - Buildipedia". buildipedia.com. Retrieved 2015-09-02.
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