Sonnengewinne

Sonnengewinne, a German term literally translating to "sun gains" or "solar gains," refers to the passive heating of a building through solar radiation. It is a fundamental concept in sustainable architecture and energy-efficient building design. When sunlight strikes a building's windows or other transparent surfaces, it enters as shortwave radiation and is absorbed by interior surfaces and objects. These surfaces then re-emit the energy as longwave infrared radiation, which cannot easily pass back through the glass, thus trapping heat inside the building.

The amount of Sonnengewinne depends on several factors, including the orientation of the building, the size and type of windows, the presence of shading devices, and the thermal mass of the building's interior. South-facing windows in the Northern Hemisphere typically receive the most direct sunlight during winter months, maximizing beneficial solar gains. Conversely, excessive solar gains during summer can lead to overheating. This is why careful design considers strategies like overhangs, awnings, or deciduous trees to shade windows during warmer periods.

Effective utilization of Sonnengewinne can significantly reduce the need for artificial heating, thereby lowering energy consumption and associated costs and greenhouse gas emissions. Architects and engineers often employ sophisticated modeling tools to predict and optimize solar gains for a specific climate and building design. The concept is integral to passive solar design, a holistic approach that aims to harness natural energy sources for heating, cooling, and lighting.