By Gary Rasp
UT Austin students and their counterparts at Technische Universitaet Muenchen (TUM) in Germany are putting the finishing touches on construction of an ultra-energy efficient, solar-powered home that will compete next month in the U.S. Department of Energy (DOE)’s Solar Decathlon 2015.
With the assistance of faculty advisors, students from the two universities have spent two years designing and building NexusHaus, an affordable residential home that features a modular green building design.
The NexusHaus unit, which includes day and nighttime living areas separated by a breezeway, is capable zero net water and has a low-carbon footprint in its use of sustainable building materials. A wooden prefabricated house forms the superstructure for photovoltaic technologies, rainwater collection, and food production.
The unit also features generous amounts of insulation, weather stripping, energy efficient LED lighting, Energy Star rated appliances, a heat pump hot water heater, and energy recovery ventilators that combine to reduce the unit’s thermal load to less than 1 ton of conditioning per 800 square foot of living space.
In the coming week, the NexusHaus team will ship the unit to California for the Solar Decathlon, in which 13 collegiate groups will compete in several categories, including architecture, engineering, and market appeal. Each team will earn points based on their entries’ performance, livability, and affordability. The competition will be held in Irvine, CA October 8 – 18.
Learn more about the competition and how Solar Decathlon entries are measured and judged.
The NexusHaus design features extensive use of wood, both as the structure for the house and as a finish material.
Solar Decathlon officials recently enacted rule changes requiring that units entered in the competition be zero net energy, meaning they are capable of generating all the electricity needed to power fixtures, appliances, and other devices and consume not more than 175kWh during the 10-days of the competition.
Because the NexusHaus unit is extremely energy efficient, it can generate enough power from its 8kW roof-mounted PV system to meet its needs and also power a BMWi3 electric vehicle. Any excess electricity is sent back to the community grid.
“The competition is much more in line with how homes are actually built,” said Charlie Upshaw, a PhD student in Mechanical Engineering who serves as NexusHaus team co-captain and project engineer.
“They’ve gone beyond just solar-powered units to sustainable advanced energy systems.”
The roof and breezeway canopy of the unit are designed to collect over 17,000-gallons of rainwater per year – more than necessary to meet potable water needs. The rainwater is stored in a 2000-gallon polyethylene bladder tank under the patio deck and is treated with a 5-micron paper filter and charcoal filter, and is disinfected with an ultraviolet light.
Students are working with representatives of the City of Austin’s Green Alley Demonstration Project and local non-profit organizations to use the NexusHaus design as a prototype for mass-produced, prefabricated housing units, known as ‘Alley Flats’ because they often face onto an alley between existing dwellings.
“Hopefully, we will be producing units in Austin,” said Megan Recher, a Masters of Architecture student and construction manager for the NexusHaus team.
“There are at least 120 different modular varieties to the design,” Recher added, noting that the units can be built on a chassis to make them easier to move.
Learn more about all of the UT Austin students participating in the NexusHaus project and view videos explaining the team’s concept, including an animated walkthrough of the project’s design.
Faculty members from the School of Architecture serve as project coordinators for the project and provide leadership in design, energy, water and lighting coordination. The UT Austin team is led by professors Petra Liedl, Michael Garrison, and lecturer Adam Pyrek.
In addition, Atila Novoselac in the Cockrell School of Engineering’s Department of Civil, Architectural and Environmental Engineering provides engineering systems analysis and integration, supported by senior lecturer Gregory Brooks. Michael Webber, Deputy Director of UT’s Energy Institute, also has been supporting the team from outset. Michael Gatto, director of the Austin Community Design and Development Center, is a consultant to the team. Professor Werner Lang leads the TUM team.
Gary Rasp is communications director for UT Austin’s Energy Institute.