Gebäudethermik

Gebäudethermik, or building thermics, is a subfield of building physics that studies the thermal behavior of built environments. It concerns the generation, transfer, and storage of heat in buildings, and how outdoor climate, internal gains, and ventilation shape energy use and indoor comfort. The aim is to analyze, predict, and optimize thermal performance across design, operation, and retrofit phases.

Key concepts include heat transfer by conduction through envelopes (walls, roofs, windows), convection in air flows, and radiative exchange with the environment; the role of thermal mass and thermal bridges; insulation and performance metrics such as U-values, thermal resistance, and thermal lag; solar gains, ventilation losses, and overheating risk in warm climates. Dynamic behavior is central, reflecting the time-dependent response to weather and occupancy.

Methods and tools: experimental measurements such as heat flux, surface and air temperatures, and airtightness testing; numerical simulation with building energy models and tools like EnergyPlus, TRNSYS, or Modelica; use of climate data and multi-zone models to assess year-round performance. Standards and guidelines govern calculation methods and comfort criteria; notable references include ISO 13790 for building energy needs and EN 15251 for indoor environmental quality, with standards addressing insulation and thermal performance of components.

Applications: design optimization for energy efficiency (including passive houses), retrofit planning, HVAC sizing, and passive cooling strategies, as well as integrating solar gains. It informs policy and certification schemes, such as energy performance certificates and near-zero-energy building targets, and supports diagnostic assessments of existing stock.