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by Dan Shalloway
Special to GreenGroup.com
LEED Accredited Professional
In my last column I discussed Water Efficiency. We will now examine one of the most complex subjects; Energy and Atmosphere.
Buildings consume approximately 68% of the energy in the United States, according to the U.S. Department of Energy. Green buildings address energy use in two ways: a). Reducing the amount of energy required and b). By using more benign forms. By lowering energy usage, operation costs are reduced. Environmental impacts are reduced by using sources other than fossil fuels or other non-renewable resources.
The first step is to establish a minimum level of energy efficiency for the proposed building systems. The building envelope, heating, ventilating and air conditioning (HVAC), lighting, and other systems are designed to maximize energy performance. Refrigeration and HVAC systems are specified with zero use of Chlorofluorocarbons (CFC). CFCs deplete the ozone and contribute to Global Warming. Eliminating CFCs is not as simple as it sounds because there is no “ideal” alternative. The use of alternative Refrigerants can have unintended consequences. For example, Hydro fluorocarbons (HFCC) have very low Ozone Depleting Potential but are not as efficient as CFCs. This means more electricity must be generated which increases CO2 emissions.
The balancing is accomplished by a systematic approach to building design. Ways of reducing overall energy use can include building orientation, shading, cool roofs and insulation. The ready availability of computer models allows architects to design the most efficient building possible.
Another strategy is to harvest site energy by using free resources such as daylight, solar heating, and natural ventilation. Waste energy can be recovered through exhaust air energy recovery systems and cogeneration.
A building can even produce their own electric power and/or thermal energy by utilizing renewable resources. These renewable energy systems are designed to capture solar, wind, geothermal, water or bio-based energy to satisfy on-site electricity or heating demands. If that is not possible, then Renewable Energy Certificates (RECs) can be purchased. By purchasing RECs you are essentially contributing to the production of electricity produced by a renewable resource, which is feed into the electric grid. This makes your building project more Green.
Every day, more energy reducing tools are available to the architects and engineers who design buildings. The key to a successful Green Building is to make all these complex components operate as a balanced system. In my next column I will look at the materials and resources used in constructing a Green Building.
Dan Shalloway is a Professional Engineer and a LEED Accredited Professional by the US Green Building Council. He writes a weekly column for GreenGroup.com. He is also the Developer of Florida’s first Green Industrial Park. In next week's column, Mr. Shalloway will examine what materials and resources are used in constructing a Green Building. You can find an archive of Mr. Shalloway's columns in the Contractor's Guide.
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