Solar Decathlon House
Austin, TX | Irvine, CA
Fall 2014- Fall 2015
Instructor: Petra Liedl, Adam Pyrek, Michael Garrison
The Solar Decathlon is a triennial competition that takes place in the United States with the aim of challenging universities and their students to design the most efficient and sustainable residential home. The competition takes place over a period of two years
and requires student teams to design and build a fully functioning house.
Built and exhibited in Irvine, California for the 2015 US Solar Decathlon, the NexusHaus addresses environmental issues and efforts in sustainability through four core concepts: energy, water, food and density.
Through a collaboration between the University of Texas at Austin and the Technische Universitat Munchen, the project also took on an international role as it fostered learning and innovation in construction methods and technology. The house was preassembled
in Austin, TX and hauled to California for final assembly under competition conditions, with the final assessment covering 10 different categories that included: energy balance, architectural innovation, engineering innovation, affordability, marketability and
efficiency. The team took 4th place overall and brought home 1st prize in energy balance, 2nd place prize in affordability and 3rd place prize for engineering.
Nexushaus incorporates a unique energy-water nexus (ExW), a system that essentially utilizes solar energy and captured water to support the house. Serving as an accessory dwelling unit, (commonly known as an inlaw) the house can be placed in the backyard
of a residential lot in Austin to operate as a unit of resource production. The house serves as a prototype for increased density in Austin as part of the Alley Flat Initiative, the goal of which is to enable lower income families to have more affordable living options that
are in the neighborhoods close to the city. By maximizing the usability of lots there is a more natural density growth without the typical gentrification that occurs with planned neighborhoods.
“The house serves as a prototype for increased density in Austin”
Environmental and economic affordability are the goals of the NexusHaus concept. The house harnesses resources (solar energy, rainwater, and auxiliary water) that would otherwise be wasted and be a burden on municipal infrastructure. Because lower-income families are more vulnerable to water and energy cost fluctuations, the ExW-Unit will increase occupants’ independence while contributing to their long-term economic, environmental, and social stability.
Air conditioning is an unavoidable fact of life in Texas and serves as the single largest load on the electricity grid during peak summer afternoon hours. To alleviate afternoon electricity grid congestion – and avoid higher-priced power – NexusHaus incorporates
an Integrated Thermal Energy and Rainwater Storage (ITHERST) system to shift air conditioning load off-peak to the early morning hours. Furthermore, the NexusHaus PV array is optimized for maximum production during hours of peak demand, decreasing the
overall load which is currently outpacing the generating capacity in Central Texas.
To reduce reliance on city water, NexusHaus will capture rainwater to provide all of its potable water needs and will only be connected to the city supply by a small refill line. The minimal supply from the city will serve as a backup during long dry spells. This potable
rainwater harvesting system minimizes added stress to the region’s water supplies and minimizes the additional load of more residents on the existing neighborhood water and wastewater infrastructure while increasing density in the city. Additionally, the on-site treatment system avoids the water losses along the municipal distribution system by approximately 10 percent, and the thermal storage tank acts as a secondary storage volume for rainwater, giving the system additional capacity while also providing beneficial load shifting. In addition to providing potable water for the home, NexusHaus’ integrated rainwater thermal storage system shifts cooling off peak to low-demand nighttime hours while reducing storm water runoff which taxes the aging infrastructure in the City of Austin.
With the need to increase food production to 70 percent by 2050 to meet demand, NexusHaus proposes an all-food residential landscape using only recycled greywater for drip irrigation – providing intensive, water-efficient gardening. An aquaponics system is also introduced for food production and water treatment. With fish, microbes, and plants, 10 to 20 times more food is produced while using 90 percent less water providing significant savings on food for the inhabitants and providing free produce in areas typically
devoid of such resources.
*My role in this project ranged from SD and DD through to construction. I specifically worked on the facade and deck elements and took part in the assembly in Irvine, CA.