Case Study: Biohaus Bemidji, MN | Concordia Language Villages | May 2006

Case Study: BioHaus Bemidji, MN | concordia language villages | may 2006

Photographer: Cal Rice PROJECT OVERVIEW DESIGN CHALLENGES The mission of Concordia College of The real challenge of the BioHaus Location Waldsee - German Lan- Moorhead, Minnesota, focuses on project was not its construction or the guage Village, Bemidji, MN “influencing the affairs of the world” unprecedented use of certain building 7 (very cold/hot and humid) and is reinforced by the mission of components but the integration of de- Climate Zone its Concordia Language Villages, sign, products, detailing and construc- Size 5,000 s.f. which emphasizes “responsible global tion to achieve an astonishing level of citizenship.” Waldsee BioHaus brings building performance—a point, which Levels 1 Level plus basement this mission to life, dazzling a new the Passive House’s stringent build- generation with a rich immersion ing envelope airtightness requirement experience in German language and [0.6 ACH50] necessitates. One partic- Construction Educational/Residential culture. It offers a natural extension to ular component that has great impact Walls Total of 6” thick with the content-rich programs of Waldsee, on the airtightness is exterior windows vacuum insulation panels the German Language Village. Stu- and doors. At the BioHaus the design for the exterior walls with dents of all ages learn about energy team sourced windows from Optiwin—a aluminum cladding, R-70 use, natural resources and how we can German manufacturer who designed all live more holistically in a sustain- one of the first certified Passive House Roof Flat with an extensive- green roof able global community. Better yet, the windows—and invited them to not just entire educational experience happens manufacture but also install the prod- Floors In-floor heating in German, using the metric system, uct on site—integrating design param- surrounded by the incredible, hands- eters, product, and installation. Mechanical Lüfta air exchange and on, natural playground of Waldsee. heat recovery system What better way to learn about the The Waldsee BioHaus is located near future than to live it! Bemidji, Minnesota, in US climate Windows Triple paned Optiwin “3-wood-window” with Waldsee BioHaus serves as a power- zone 7—the coldest part of the country shading device ful catalyst for debate appealing to a with 10,200 heating-degree days. The new generation of villagers, students Passive House standard was devel- Cost/Benefit Less than $900 of energy and architectural, construction and oped in—and for—a much more moder- costs per year. Perfo,rs environmental professionals commit- ate central European climate with an 85% below the current ted to advancing sustainable design average of only 6,300 heating-degree Minnesota energy code and quality of life. days. With the BioHaus project, it would see its first real-world test in an environment with seriously limiting conditions.

01 DESIGN SOLUTIONS - BUILDING ENVELOPE to illustrate a maximum of 0.6 air changes at 50 Pascal In response to its location and the design parameters the pressure [0.6 ACH50]. Thanks to the diligent design and BioHaus’ building envelope is extremely well insulated to construction the BioHaus excelled with a measured 0.18 prevent heat loss. Walls achieve an R-value of 70, while the ACH50 surpassing not only the Passive House limit by an roof’s insulation value sits at 100. Stephan Tanner and his impressive margin but besting conventional new construc- design team at Intep engineered two different wall sections tion [2.0 – 5.0 ACH50] considerably. to illustrate different paradigms. A 20-inch ‘thick’ wall uti- lizes conventional building materials, while an 8-inch ‘thin’ wall assembly leverages cutting-edge vacuum insulation DESIGN SOLUTIONS - BUILDING SITE panel (VIP) technology from Germany. Both perform at the The extremely cold climate is one reason the Bemidji area same level. The building envelope is designed to minimize serves as a cold weather automotive performance-testing the need for ‘useful energy’. Useful energy is defined as site for automobile manufacturers from around the world, the energy that is directly accessible to the user. Useful including some German companies. The use of the Passive energy includes space heat, domestic hot water or lighting. House performance standard produced a design for the BioHaus, which uses 85% less energy than a comparable Once again, windows play a major role in the design and structure built to local codes. On campus the BioHaus is achievement of the performance goals. In this design, win- located adjacent to the central Marktplatz [market place] dows facing East, South and West are optimally protected to the east of the Stadtpark [city park] on a south-sloping from summer heat gains while allowing low winter sun lot with partial winter views of Turtle River Lake. angles to provide heating energy. An active shading system comprised of exterior venetian blinds modulates solar The site is moderately wooded with a variety of tree heat gains and daylighting on the south façade. The top species. An opening in the tree cover to the south of the and bottom of each shade can be individually controlled to site was cut to allow sufficient solar access. The Waldsee achieve both at the same time. campus is predominantly a pedestrian only environment. Vehicle access is limited to emergency vehicles to the Bio- The airtightness of a Passive House building envelope Haus’ main entrances on the West and South sides. Trails demands special attention. Uncontrolled air exchanges are connect to the neighboring language villages surrounding to be minimized and a blower door test to be performed Turtle River Lake, as well as the local beach.

Photographer: Cal Rice 02 “In Europe, architects don’t view green technologies as individual building components. Their approach is a more holistic one, for all the sustainable design components to work in harmony ... for the building itself to be integrated with nature not stand separate from it ... for the living and learning spaces Photographer: Cal Rice of BioHaus to reinforce the rich, hands-on learning experience that is core to Concor- dia Language Villages. It’s this wholeness of the building that I believe makes Waldsee BioHaus so special.”

- Stephan Tanner, INTEP, LLC BioHaus architect

Photographer: Cal Rice

DESIGN SOLUTIONS - MEP SYS- roof, which also serve as the sources TEMS for the domestic hot water system. Be- The mechanical system in a Passive tween the coefficient of productivity House is typically dominated by a of the heatpump and the solar thermal high-performance ventilation system. input both system dramatically reduce The one in the BioHaus continu- source-energy needs. ously supplies outside air—there is no recirculation. Wetrooms and auxiliary DESIGN BENEFITS spaces are continuously exhausted Concordia Language Villages believes to the outside. In an effort to reduce that architects, engineers, contractors operations energy for pre-heating and staff are responsible for creat- or pre-cooling and dehumidification, ing the most educationally inspiring, the ventilation system connects to an efficient and cost-effective building earthtube system. Fresh air is taken possible. Through the BioHaus project, into the building is via this under- Concordia Language Villages is able to ground network of pipes. A bypass was commit to: installed to allow for the direct intake of outside air during times when tem- • Reduced life cycle costs pering of the intake air is not needed. • Enhanced occupancy comfort • Improved learning environments The BioHaus’ Passive House design did not require a stand-alone heating • Extended life expectancy of system as the heating demand can be each building met with a post-heater for the venti- • Reduced maintenance lation system. Due to a request of a • Reduced environmental impacts project sponsor however the decision was made to install an in-floor heating system to provide the heating load and Waldsee BioHaus occupants enjoy to forego ventilation air heating. The an improved quality of life inside the system is fueled by a combination of building that uses 85% less energy a ground-source heatpump and solar than a conventional structure. thermal energy from collectors on the

Photographer: Cal Rice

03 ACHIEVEMENTS design, a carefully selected team of designers and builders, Built in 2005/06 the BioHaus is the first certified Passive effective collaboration and communication, quality control, House in North America. Located in a severe heating cli- and proper commissioning. mate, it is also the first commercial Passive House building in the U.S. It is now in its sixth year of operation producing LESSONS LEARNED – MEP DESIGN amazing results for the owner: The design of a small-load heating system requires a great amount of professional know-how and experience. In this • It works! The first five years of operation have shown case, the design of the hydronic heating system proved that it is possible to build a Passive House in an ex- too difficult for the team and as such does not work as treme climate and with a local contractor designed—even though individual components are fully • The initial investment cost (approx. $260/sf) for this functioning. As a result, space heat is only being provided prototype and first of its kind were only about 20% by the ground-source heatpump system, and not augment- above comparable educational facilities. This includes ed by the solar thermal panels on the roof. The building’s added cost for imported products like windows/doors, performance however, has exceeded the predicted perfor- ventilations system, exterior shading needed for the mance 4 out of 5 years. design, redundant systems, as well as the cutting-edge vacuum insulated panel (VIP) insulation system, that is typically only used in projects where useable square A GREAT IDEA THAT WORKED REALLY WELL : footage is extremely expensive Trying to have fun while working on the project. • The space heating demand is reduced by 90% com- pared to conventional designs. At the same time occupants experience a new higher level of comfort OWNER FEEDBACK Concordia Language Villages and its deans ‘Karl’ Hamilton LESSONS LEARNED - PROCESS and Edwin Dehler-Setter have been able to develop and ex- The design of a high-performance structure like the Wald- pand their vision of an ‘environmental living center’ and stu- see BioHaus requires detailed planning by a highly skilled dents ‘fight’ to stay and live at the BioHaus year-in and out. design team. The achievement is comparable to extreme mountaineering—necessitating strong and experienced COST ANALYSIS leadership and a highly motivated team to make it safely The German Foundation for the Environment funded most all the way to the peak. The long-term success relies on of the cost of the Waldsee BioHaus with the intention to carefully crafted details and a proper understanding of demonstrate the German understanding of world-leading building science, the design of appropriate building enve- environmentally appropriate living, and to support Concor- lope systems, the evaluation and design of thermal-bridge dia Language Villages’ goal to develop an environmental free connection details, and a clear strategy for a durable immersion curriculum that leverages a building as its main air infiltration barrier. These skills need to be combined tool. With the building being built on budget, and annual with a “keep it simple” approach to allow for effective energy cost of only $900 [5-year average] the BioHaus is execution on the job site. In summary, the BioHaus suc- considered a huge success by its owners. cess is founded in concise planning for a high-performance

Architect: Client Building Technical Systems

Intep, LLC Concordia Language Villages 8659 Intep, Integrale Plannung GmbH 212 2nd St. SE, Suite 222E Thorsonveien NE Bemidji, MN 56601 Innere Wiener Strasse 11 Minneapolis, MN 55404 USA USA D-81667 München Germany Contact: Contact: Stephan Tanner, Principal Warren Schulze, Director of Facilities Contact: ++1-612-339-5515 ++1-218-586-8502 Thomas Rühle, Principal ++49- [email protected] [email protected] (0)89-45-99-490 [email protected]