Freiburg Heliotrop. Photo Credit: Andrew Glaser, Wikimedia Commons

The Ignite session I attended on building design provided a glimpse into strategies to attain zero-energy buildings. Whether it was rebuilding a safe and eco-friendly city in Kaimishi, Japan; retrofitting a cooling-intensive ice cream shop; or students building a passive solar residential home with solar PV, solar thermal, and geothermal we learned the techniques to make existing structures or even new construction energy efficient. Key highlights from the session included:

• Thomas Spiegelhalter’s “Designing Carbon Neutral Plus Energy Buildings With Site Adaptive Heliotropism Cycles”: I must admit I had to look up heliotropism but this was by far the most interesting presentation since it involved a bit of biomimicry, a subject close to my heart. These German presenters studied how native plants in the area used their flowers or leaves to follow the sun (heliotropism). The engineers then incorporated the physics of this motion into the building design. Essentially, the building’s solar PV module on the roof mimicked the motion of these native area plants through the day to maximize the capture of solar radiation. The building ends up with a surplus of energy at the end of the year.

• Dan Staley’s “Trees and Solar Power, Coexisting in Urban Forest Near You”: We all know solar PV’s nemesis is tree shading. However, trees are an effective means of cooling, air cleaning, storing carbon, and providing natural beauty to the urban environment. How can we solve this dilemma? Through cooperation of course. Staley provided a blueprint of how arborists and solar providers can work together and plan an urban environment so that structures receive maximum benefit from trees and solar radiation. Staley suggested designing houses and tree placement before the lots are built and also changing street orientation for optimum solar gain. And he advised that there should be plant lists for neighborhoods with information on how fast they will grow and the canopy size as well as training arborists on solar smart pruning.

We all know the importance of making our buildings more energy efficient first and then adding renewables second and from the sound of it these presenters not only did it in that order, but it seemed like they came up with some unique methods in the process. What are others doing to make buildings more energy efficient?