Energy efficiency and sustainability attributes of the solar decathlon projects

The use of solar energy as a renewable energy source to reduce fossil fuel consumption is now widely accepted as one of the best ways to mitigate pollution problems and improve living conditions. Solar Decathlon Competition has been developed by the Department of Energy (DOE) to encourage the use of solar energy and other renewable energy sources toward the goal of building sustainable houses. This competition was held in 2002 for the first time. Since then, it has taken place every two years in 2005, 2007, 2009, 2011 and 2013. In order to learn from such experiences, we need to study different components of these well-documented competition houses, which could lead to better understanding of the application of different innovative materials and methods in construction of even conventional but energy efficient homes. In this paper, the past Solar Decathlon Competition projects are reviewed in order to categorize major components of the buildings. In order to evaluate the effect of the components used on sustainability and energy efficiency, various criteria developed by the solar decathlon competition rules are used. Some of these criteria have varied over the years, but the major ones can be summarized as follows: architecture, appliances, lighting, hot water, market appeal, affordability, comfort zone performance, and energy balance. The components that will be discussed in this paper include floors, roof, structural framing type, wall systems, windows, and insulation materials. The attributes of such components are evaluated considering certain aspects of sustainability relevant to Solar Decathlon projects. Furthermore, the percentages of different structural framing, insulation and glazing types among other major components used in the design are determined and presented.