“The sunflower effect is created by combining two motions: the rotation of the building itself, of 180° throughout the day, and the rotation of the photovoltaic roofing hood, to ensure an inclination of 90º of this surface relative to the sun’s position (angle that optimizes PV production),” according to the group’s website. Silva says the combined rotation of the building and roof produces 25,000 kWh/year of electricity or five times as much energy as a home this size would typically require to run.
Pre-programmed to track the sun, the home uses the equivalent of six 60 watt light bulbs running for one hour to rotate each day – a negligible sum considering how much energy it generates. Silva says articulated movements of the mobile hood have also been designed to control the effects of light and shade, providing protection against solar gain in summer and resulting in an 80 percent reduction in cooling costs. In winter, the roof hood moves along an axis in the upper part of the building structure, ensuring maximum solar gain. The rotation affects the home’s interior dynamic as well.
Related: Solaleya Domespace homes gently rotate to catch the most sun
“For instance, in the morning, the kitchen can be smaller, as 21st century families’ daily routine seldom allows everyone to have breakfast together; by night, it can fuse with the living room, allowing the family to spend time together at the end of the day while cooking/eating dinner.”
In Portugal, the average time for the daily movement is 9 hours in winter and 15 hours in summer. The user can manually change the speed, in which case rotation will require at least 12 minutes, according to Silva. He emphasizes that the rotation won’t create disruption inside (in other words, your dishes won’t go crashing to the floor each time the house moves to chase the sun.)
When Casas em Movimento presented their design to MIT, they were advised to initially target a high-end market, resulting in a fairly steep price of 6,387 euros per square meter. In time, they hope to bring that way down. “Our strategy is to continue to optimize the technology and all processes, so that we can in the future reach broader market segments at lower costs,” Silva said. “Our long-term objective is to reach the same price for square meter as conventional buildings.”
+ Casas em Movimento