Only a few weeks ago, in the parking lot of an old Mitsubishi dealership not far from the campus of Appalachian State University in Boone, N.C., six modular building pieces were craned one at a time into place, then cladded with an “urban shell” — an insulated structural envelope — to create a two-story, 1,100 sq. ft. solar powered row house.

The house is called Maison Reciprocity, an amalgam of English and French that means “reciprocal house,” and it is the work of Team Réciprocité, a collaboration between Appalachian State and Université d’Angers, a school located in the Loire Valley in France. On June 4th, the six disassembled modules were packed in shipping containers and sent overseas as the team’s entry in the Solar Decathlon Europe 2014 to be held in Versailles — a fitting location, as it was once the home of the “Sun King,” Louis XIV.

Twenty teams from 16 different countries will compete for awards in such categories as energy efficiency, materials sustainability, innovation, livability and even public communications and outreach. The entire team consists of undergraduate and graduate students, faculty members and industrial partners (from both sides of the Atlantic) working in fields as diverse as project site administration, typography and environmental design.

The communications manager for Team Réciprocité is Mark Bridges, who is a graduate student at Appalachian State getting his degree in sustainable design and construction.

“I’ve been involved in the program here for almost five years,” Bridges says, referring to his involvement in the U.S. Solar Decathlon back in 2011.

The Solar Decathlon began as a project sponsored by the U.S. Department of Energy in 2002 to spur research and development in new technologies. Since then, the event has spread to Europe and China, with its standards and parameters becoming ever more exacting in the hope of driving innovation.

“In 2010 you were allowed 15 kW [to power your house],” Bridges says. “In 2012 you were allowed 10 kW, and now we’re allowed only 5 kW.” The official rules for the contest now run to 47 pages.

Along with innovation, the contest tries to encourage affordability and usability.

“You don’t want a home that’s going to cost you $350,000, and be superlight, energy-efficient, but that no one can afford,” Bridges explains.

Contestants are working to solve the problems not of individuals but of communities, and for the Decathlon Europe the emphasis is on dense urban communities. Problems of density were what led Team Réciprocité to a row house design.

“It has spanned generations and cultures and still survives today as an effective density solution,” Bridges says. “It gives you even lot lines, shared, idiomatic walls; it gives you community access; it gives you rentable space if you want mixed-income, mixed use.”

All the building’s mechanical, electrical and plumbing systems are located within the CHORD, which stands for Container for High-Performance Operation, Recirculation and Distribution. A student-created algorithm coupled with Arduino-based software and hardware control the systems using feedback loops to determine how quickly comfort conditions are met.

The mechanical systems include a custom, student-designed and manufactured Integrated Solar Air-to-Air collector and Air-to-Air Phase Change Storage system (ISAAC and AAPS), a Zhender ComfoAir 200 energy recovery ventilator, a customized desiccant wheel dehumidification system, a Viessmann solar thermal system, and a high-efficiency water-to-air heat pump made by Panasonic, model Aquarea 5 kW MonoBloc.

The building’s algorithm seeks to first use energy from ISAAC and AAPS, then the solar thermal system, and finally the heat pump. The dehumidification system and the ERVs are used as necessary throughout both heating and cooling cycles based on sensors, feedback loops or passive conditioning strategies like night flushing. A Haiku ceiling fan from Big Ass Fan Co. prevents stratified temperatures in the building’s high vaulted rooms.

The three-collector (18 tubes per collector) Viessmann Vitosol 200-T SPE solar thermal system is sized to provide nearly 100% of the building’s predicted hot water demand and meet a significant portion of its annual heating requirement. The drainback system uses evacuated tube collectors as well as variable speed, high-efficiency Grundfos Magna 3 circulators and two A.O. Smith SUNX-80 hot water storage tanks.

One storage tank is used for domestic hot water and the other is used as an HVAC process heat storage tank. A three-way valve switches between which tank is heated by the solar thermal collectors, again based on the algorithm that gives priority to heating domestic hot water. The 4.5 kW backup heating element can represent a significant electrical load when activated. Heat from the process heat storage tank is used in a heat exchanger located directly in a modified air handler as well as for regenerating the desiccant wheel in the dehumidification system.

The building features two bathrooms, one for each level, and a rail kitchen located on the main floor. Both use low-flow fixtures from Produits Neptune and Moen. Toilets from Toto are low-flow, dual-flush models with space-saving, in-wall tank design.

The building is constructed using innovative, sustainable materials such as cross-laminated timber, insulating glass and polyisocyanurate board and mineral wool. When the CHORD control module is combined with the living and shelter module (called the Brise-Soleil) and then wrapped with the insulated urban shell, the result is a solar-powered prototype home that is market-ready and adaptable.

Contestants began to construct their buildings June 16, giving them just 10 days before opening ceremonies on June 27.

“Actually, it’s more like nine days because the French do not work on Sundays,” Bridges says. “We could have really used that extra day. But the modules will be put back together with a team of about 36 students doing around-the-clock construction work in three different teams in eight-hour shifts.”

The competition will include three weeks of tours for the public, press, sponsors, educators and industry professionals from all over the world. Some of those professionals will be tasked with judging, and almost no aspect of the project is overlooked. Six juries are set up to evaluate: architecture; engineering and construction; energy efficiency; communication and social awareness; urban design, transportation and affordability; and sustainability.

“For example,” Bridges says, “there are four professional communications people that I will speak to on two occasions to tell them how we’ve raised awareness and done outreach for our project.”

To learn more about Solar Decathlon Europe 2014, visit To follow the progress of Maison Reciprocity, friend them on FaceBook at, or read Mark Bridges’ blog at