Ultra-low energy homes create new benchmarks for Army housing  

Mar. 31, 2008

By Justin Ward
Europe District

The Army will soon have a new shade of green.

Through a partnership with the Installation Management Command-Europe (IMCOM-E) and the Nürnberg bauamt (or state construction office), the U.S. Army Corps of Engineers has voluntarily agreed to set a new benchmark for Army Family Housing projects in Europe - an entire neighborhood of ultra-low energy townhouses.

The new energy standards, known in Germany as Passivhaus standards, are similar to LEED (Leadership in Energy and Environment Design) or SPiRiT (Sustainable Project Rating Tool) paradigms used in the U.S., said Michael Hogg, the former project manager for the project.  But Passivhaus standards are much more rigorous, he said.  Much more.

"Although it's hard to compare scales, the goal is that our Passiv-houses will use about ¼ of the energy demanded by typical facilities constructed in Germany," Hogg said.  "And these rating system levels already surpass average American standards.  So this is really above and beyond anything we've done before."

The new neighborhood, to be located in Urlas, an Army community in Ansbach, Germany, started with a discussion between the U.S. Army Corps of Engineers, IMCOM-E, and the Ansbach Directorate of Public Works (DPW).

"The main impulse came from the project manager from IMCOM-E, who, along with the Ansbach garrison, was interested in building a showcase for the world to see," said Wolfgang Hagenau, an Ansbach DPW environmental contractor.  "These houses will be like a business card the garrison and IMCOM can give to everyone, showing that the garrison is developing in a sustainable way."

Hagenau said the Ansbach DPW and the civilian employees at the garrison were very "keen" on the project and believes that the Passiv-houses will greatly advance the reputation of the U.S. Army to the most environmentally aware German citizens.

How it works
Still in the design process, these Passivhaus townhouses will incorporate a "whole building" perspective, which entails not only responsible stewardship of natural resources, but also responsible stewardship of financial resources through lower operating costs and improved facility life-cycle management, said Karla Krieger, project manager.

They're called Passiv (or passive, in English) because the interior climate is intended to be maintained without active heating and cooling systems.  Thus, the house heats and cools itself.

The way it does this, said Krieger, is very complex, involving a precise interior airflow design using computational fluid dynamics, multizonal airflow models, and an innovative heat exchange system.

"The way in which it recovers heat during the winter is probably the most interesting part of a Passivhaus," Krieger said.  "Especially here in Central Europe, where the winters are often very cold."

Like many low-energy houses, Passivhaus standards include the employment of specialized thermal insulation, triple-paned and insulated glazed window technology, and carefully sealed air barriers, all of which serve to retain existing and incoming solar heat.

However, fundamental to the Passivhaus is the innovative heat exchange system, which controls building temperature using only the normal volume of ventilation air.  It does this by heating ventilation air from the hot water tank and then recovering about 92 percent of "waste" heat from the exhaust air.

It even recycles "waste" heat from major appliances, lighting fixtures and body heat from people or animals inside the building.

Additionally, plans are in the works to supplement the current energy demand from these houses with renewable energy sources such as thermal solar panels.

"To be honest, only mechanical engineers will probably understand how the system works," Krieger said.  "But what's important is that it works and that it's easy to operate for those living in the townhouses."

In fact, according to the Passivhaus Institute's Web site, living in a Passivhaus does not require an advanced degree.  "Passivhaus technology is so simple, there's no need to hire someone to perform annual air filter changes," the site explains.  "The ventilation system has fewer controls than a normal television."

The finished product
Living in these new townhouses will be junior and senior noncommissioned officers and field-grade officers from the 12th Combat Aviation Brigade, U.S. Army Europe's first modular aviation unit, merging Soldiers from five units around Germany.  These Soldiers will move into their new homes - anticipated to be run by low-energy appliances - in 2010, Krieger said, when Phase I is scheduled to be completed.

In total, Phase I includes 138 dwelling units, 22 of which are scheduled as Passiv-houses.  The remaining 116 units in Phase I will adhere to what's known as the EnEV standard, the current German energy-saving standard, which still bests the typical American standard.

Phases II and III, which combined call for another 392 dwelling units, might also include Passivhaus neighborhoods, Krieger said.  But that decision has yet to be made.

Another first for the Urlas community, said Dorothy Richards, Army housing program manager, is that those 12th CAB Soldiers will also be living in the Army's first townhouses to be constructed in Europe.

"Just the fact that these new dwelling units are townhouses is important for the Army, not to mention that many of them will be designed with environmentally responsible practices," Richards said.  "Generally speaking, I think the townhouse is a better option for the warfighter and their family members because it gives them the higher quality of life that they deserve - one that fits the sacrifice they're making for this country. And I hope we can continue to design and build to the townhouse standard."

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