The "Passivhaus Darmstadt-Kranichstein" is a 4 unit terrace house with an extremely low total annual energy consumption of less than 32 kWh/m² of living area, thereof about 12 kWh are needed for room heating /Feist 1994/. The determinig factors for the low consumption are the superinsulation, airtightness of the thermal envelope in combination with a highly efficient VAV ventilation system, and an improved window construction. The "Passivhaus" therfore is a typical example of an improved low energy house.
The present study intends to optimize the concept of a breast-wall panel while conciliating the architectural aspects and energy saving strategies of non residential buildings. Thus, the panel will permit besides a recovering of solar energy gains during the winter as in a classical Trombe wall (but without is thermal inertia) a reduction of solar energy inputs during summer. In order to estimate its thermal performance, a simplified model was developed predicting energy savings both in winter and in summer periods.