Zero Energy: Designing and Monitoring a Zero Energy Building that Works: The Science House in Minnesota
Jason Steinbock, David Eijadi, Tom McDougall, Prasad Vaidya, Jeff Weier | 2006
Recognized at European Council for an Energy-Efficient Economy (ECEEE) 2005 for innovation, the challenge of the Science House at the Science Museum of Minnesota was to create habitable, cold climate architecture that was a net zero energy building and to get it built in a “low bid” environment. The team used science to resolve design integration conflicts between functionality, aesthetics and performance. The team significantly reduced annual energy consumption beginning with expectations of use by the owner and architectural form and then adding a renewable energy source. The defining question became “how much building and power generation can we build with the given budget?” The resulting building uses passive solar design, daylighting, ground source heat pumps and photovoltaic (PV) panels as the major design strategies. This paper documents the predicted energy use, the actual monitored performance and compares back to a calibrated DOE-2 model. It shows the extent of load reduction achieved with passive solar design. A challenge for getting to ‘real zero’ is the difference between expected performance and actual building performance. This paper illustrates how measured data is used to trace the causes to unexpected equipment performance, heat pump behavior and off-line PV panels. Assumptions regarding occupancy and building use during the design phase often differ from their actual use; this makes operating a building for zero energy an additional challenge beyond just designing one. Overall, the actual building is exceeding the goals, using on average 6.6 kWh/ sf annually and generating 9.1 kWh/sf to actually become a building that generates more energy than it uses.