International
. Sitting on a piece of land roughly the size of a football field in a former cargo yard in Heidelberg, Germany, a new complex of 162 apartments called Heidelberg Village is part of the Bahnstadt District, which will be the largest passive house development in the world.
To meet the demanding level of the "Passivhaus" standard, buildings can only use a small amount of energy for heating and cooling. Even with the cold German winters, the resort will never use more than 15 kilowatt-hours of energy for heating per square meter in a year; a "normal" building could use 100 to 300 kWh.
The scale of development currently made it easier to save energy. "The reason is the volume-to-surface ratio," says Wolfgang Frey, director of Frey Architekten, the sustainable architecture studio that designed the complex. The buildings: one five stories high, and the other ranging from five to eight stories are covered with solar panels that produce energy on the facades, not just on the roof.
The placement of the panels and buildings also help save energy. "Because we are able to produce shade with solar panels, they have a dual purpose: energy production all the time and cooling in the summer," Says. "Because homes are so close together, you lose less heat and produce more energy by using as many surfaces as we can to generate it."
The design is as airtight as possible, but it also includes windows that can be opened, something that used to be rare in buildings meant to be ultra-efficient.
Source: www.fastcoexist.com
