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2015 Solar Decathlon: Aggie Sol Home

University of California, Davis

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U.S. Department of Energy


  • Team Leaders: Ben Hu, Ben White, Claire De Camp, Elsa Lu, Frank Loge, Mahan Soltanzadeh, Payman Alemi, Robert Good, Sandeep Singh, Shahab Faghri, Tina Chen, Tom Ryan, Vivian Phan

Project Status

Student Work

Year Completed



995 sq. feet
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Project Description


UC Davis is participating in the U.S. Department of Energy’s Solar Decathlon Competition for the first time in 2015 and have devoted their efforts to providing sustainable zero-net energy housing that farm workers can afford. Identifying and targeting a problem at the intersection of agriculture, energy, economic and social issues is typical of the University’s multidisciplinary approach to problem solving and this effort is intended to address the chronic problem of a lack of quality affordable housing in the state.

The Aggie Sol home is approximately 995 square feet and relies on innovative approaches to heating and cooling. The team’s “Night Sky” system utilizes evaporative cooling to passively chill water during the evening for use in an in-floor radiant cooling system during the day. Home heating is accomplished by passive solar heat gain in addition to high-efficiency electrical water heaters powered by solar photovoltaics. A highly insulated and sealed building envelope combined with the high thermal mass provided by concrete floor underlayment reduces heating and cooling demands and helps to maintain even interior temperatures throughout a 24-hour cycle. A graywater heat recovery system supplements the Night Sky system and reduces the home’s energy loads by approximately 15%.

The home’s butterfly roof works in conjunction with the Night Sky system, capturing, collecting and directing the system’s water to an insulated storage tank. Water lost through evaporation is made up for by the roof’s capture of rainfall. On an annual basis the home is anticipated to generate a water surplus based on rainfall capture and reuse as well as graywater capture and reuse, thus not adding to ongoing water supply stress in the state.

The need to reduce interior contaminants was frequently identified as a needed feature during preliminary research and design. The team’s focus on farmworker needs resulted in the inclusion of a “cleansing room”, where residents returning from a days work can bathe and change clothes without entering the main living space of the home. This space could easily be adapted for non-farm worker use into an additional small bedroom, study, or storage space.

A goal of the UC Davis team was for the Aggie Sol home to be designed and built entirely by students. With minor exceptions for specialized areas of construction such as electrical wiring, the team has realized this goal. Designing and building the home on campus has been a tremendous experiential learning opportunity for students and has introduced many of them to the building design and construction industries for the first time. Many have developed an interest in the related fields and revised their career goals as a result.

With affordability and mass-market potential as goals, the Aggie Sol team chose readily available and standard construction materials for use in the home. The team believes that it is possible to provide quality housing at below market-rate prices that will comply with California’s pending mandate for ZNE housing if creative thinking and attention to design are applied. The Aggie Sol project is the team’s attempt to address serious economic, environmental, and social problems in the state and across the country. The team’s entry into the 2015 Solar Decathlon is UC Davis’s first visible step in solving these issues.

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