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Case Studies: Science House at the Science Museum

GENERAL INFORMATIONScience House

Project name: Science House

Location: Science Museum of Minnesota, St. Paul, MN

Web sites: www.smm.org/sciencehouse/about , www.smm.org/trc, www.bldgdesign.com, www.twgi.com, www.lsblack.com, www.eere.energy.gov/buildings/database/overview.cfm?ProjectID=284

Architect: Janis LaDouceur, Barbour LaDouceur Design Group

Builder: LS Black Constructors, Inc.

Energy consultant: Jason Steinbock, The Weidt Group

Building size: 1,690 sf

Building use: Teacher Resource Center

Date construction was completed: Original construction - June 2003. Remodeling - May 2007

Ratings and awards:

  • Most Innovative Method or Result (Getting to zero: Experiences of designing and monitoring a zero-emissions building - the Science House in Minnesota), European Council for an Energy-efficient Economy, May 29, 2005, Mandelieu, Côte d'Azur, France
  • Environmental Sensitivity Award, Minneapolis-St. Paul Chapter of the Construction Specifications Institute, Annual Awards Banquet, May 10, 2004, Minneapolis.
  • Environmental Achievement Award in the Energy Category, Minnesota Environmental Initiative, Annual Awards Banquet, May 6, 2004, Minneapolis.
  • Excellence in Building Educational Achievement Award, The Energy & Environmental Building Association, Building Solutions Conference, October 18, 2003, Chicago, Illinois

OVERVIEW

The Science House at the Minnesota Science Museum was designed as a zero-emissions demonstration facility and is currently used as a Resource Center for Educators. Through careful planning and collaboration, the design team chose to match energy efficient strategies with solar electric technology for developing a project that integrates the sun's energy for providing light, power, and heat. The Science house was equipped for ongoing monitoring of the building's performance, providing educational data for informing future building designs.

The Science House runs entirely on solar electricity. Producing more electricity than it uses from mid March through early November, it then consumes more than it generates from early November to mid March. The resulting net surplus of energy means that the Science House produces more electricity than it uses on an annual basis. Instead of storing electricity, the Science House feeds energy to the Science Museum whenever it is producing a surplus and draws current from the Museum whenever it is consuming more electricity than it is producing.

The solar electric system powers the ground-source heat pump that uses the Earth's constant temperature below the frost line of about 9oC (49oF) to heat the building in winter and cool it in summer. Energy-efficient windows and doors and wall insulation are combined with passive solar heating and careful lighting design.

BUILDING PERFORMANCE

Effective energy use solutions:

  • Econar ground-source heat pump to heat and cool the building and to supplement the domestic hot water
  • Energy-efficient Andersen windows and doors
  • Icynene insulation
  • Lighting controls

Orientation: South

Daylighting strategies:

  • Ground floor south-facing windows combined with both north and south-facing clerestory windows help ensure that daylight is distributed evenly through most of the building, minimizing the need for artificial lighting.
  • Properly sized overhangs to prevent solar heat gain in warm seasons.
  • Light colors were selected for the interior to help with daylighting.
  • Motion detectors automatically shut off lights if rooms are left unoccupied.
  • Photosensors automatically dim and brighten the fluorescent lights in response to changes in the amount of lighting being provided by the sun.

Passive Heating and Cooling Strategies:

  • The building's south-facing, energy-efficient windows combined with a tight, well-insulated building envelop permit the sun to provide all of the heat energy necessary to keep the Science House at its temperature set point even on cold winter days.
  • Sun angles were used to determine the size of the overhangs tallow for winter season solar heat gain.
  • The concrete floor serves as thermal mass for storing the heat gain during the day and helping to balance the inside temperatures by slowly releasing captured heat.
  • Building placement set into the northern slope allows for an Earth berm to insulate a portion of the structure.
  • Natural ventilation occurs through operable low windows on the south side combined with clerestory windows and the entry tower allow for a chimney effect to help cool the building by exhausting heat during the summer.

Shading of structure: 2' overhangs

Envelope:

  • Wall thickness: 2" x 6" walls
  • Insulation R-values: Icynene spray-in foam insulation
    • Roof: R-43, U-0.023, 10" of ceiling insulation
    • Wall: R-28, U-0.035
    • Foundation: R-11, U-0.091 for slab perimeter insulation
  • Building tightness: Specific attention was given to detailing the seams and prevention of thermal bridging and energy loss through a tight building.
  • Windows:
    • U-0.32, R-3
    • High efficiency double pane Andersen window assembly

Climate control systems:

  • Four ton ground source heat pump
  • Forced air
  • Energy recovery ventilation

Backup heating/power:

  • Electric resistance heating
  • Utility grid inter-tie through the Science Museum

Total building energy use: 7,269 kWh, at 60% lower than the code base

RENEWABLE ENERGY SYSTEM INFORMATION

Solar system description and size:

  • The photovoltaic thin-film adhered to the troughs of the standing seam metal roofs of the building and the adjacent shed make electricity from the sun.
  • The slope of the roof was adjusted to match the sun's angle to improve production of solar energy. This integration into the design and structure of the building allows for different design decisions to be made about the shape of the building.
  • At the same time, this integration of systems extends the life of the metal roof while reducing the need for racks for mounting panels.
  • 10.2 kW Unisolar PV laminate

Financial incentives/donations: A grant from Xcel Energy's Renewable Development Fund covered the cost of the PV roof.

Date installation was completed: 1st 8.8 kW - June 2003, Additional 1.4 kW April 2007

System designer: Innovative Power Systems

Engineer: The Weidt Group

Installer: Innovative Power Systems

Estimated amount of energy delivered by system: 10,655 kWh

Actual monitored energy delivered by the system: 10,083 kWh (for the 8.8 kW system. 12 months of monitoring data on the 10.2 kW system is not yet available). To see a current Excel spreadsheet of the energy production/consumption visit: www.smm.org/buzz/media_static/science_house_data/data_latest.xls

TOOLS UTILIZED

Modeling software: DOE-2.1E was used by the Weidt Group to analyze thermal energy and lighting simulations for the building.

MOTIVATION FOR INSTALLATION

The primary objective of this project was to test the idea of whether it is possible to design, build, and operate a building in this climate that is able to supply all of its energy needs from renewable energy on an annual basis.

LESSONS LEARNED

It is possible to design, build, and operate a zero-emissions building in Minnesota.

The Science House, both as a building and as a design process, was conceived as experimental in nature. As the team developed the project, it confirmed many of the original assumptions and discovered some unexpected challenges. Site conditions had a noticeable impact on project resources and the final building location. Because of the site's geologic and commercial history, the project team devoted significant time and money to designing a stable building platform. The team even considered floating the building in a pond.

A zero-energy building comes with design trade-offs. The capability of the photovoltaic system, as well as its module size, directly impacted the size and shape of the building. The Science House's window placement, in contrast to being based exclusively on views and facade composition, was based almost entirely on its impact on the building's energy efficiency through passive solar and daylighting strategies.

During construction, additional logistic considerations had to be made to assemble the photovoltaic system on site while coordinating with other disciplines and weather conditions. The client wanted the mechanical systems visible for use as an educational tool; although this may benefit this particular program, the impact on acoustics would make this arrangement undesirable in most situations.

Source: www.eere.energy.gov/buildings/database/lessons.cfm?ProjectID=284

OTHER INFORMATION

Other Sustainable Features:

  • Solar electricity powers a ground-source heat pump that circulates a non-toxic fluid through plastic tubes looped down four, 250-feet-deep wells. The heat pump extracts heat from the Earth to warm the Science House in winter. The heat pump extracts heat from the Science House and dissipates it into the Earth to cool the Science House in summer.
  • Energy-efficient lighting and lighting controls minimize the use of electricity to light the Science House.
  • Spray-in foam insulation in the walls and ceiling creates a building envelope with a high R-value and minimal uncontrolled air infiltration.

Source: www.smm.org/sciencehouse/about/

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