Investigating overheating by measurement and simulation in classrooms

Abstract

New two-story wood-construction classrooms where added to an existing heavy-weight construction school building in the year 2006. The glass façade of some classrooms is south oriented. The building design meets the local thermal protection requirement of 2006, but the indoor temperature rises above thermal comfort conditions in the classrooms. As usual in Germany, no active cooling device is and shall be used. Measurements during holidays with close to none internal loads in addition to measurements during regular school occupancy documented the overheating. The measurement results were used to verify a baseline hygrothermal building simulation model that represents the status quo. Various passive measures with regards to construction, design and operation to improve the thermal comfort were assessed. Among them are ventilation strategies and solar protection foil on the glass façade. Furthermore, the already installed temporary sunscreen devices and mechanical night ventilation system coupled to mechanically openable skylights above the classroom doors and within the gravel covered flat roof were investigated with different operating strategies. This paper presents the required steps to improve the simulation model with the measured data in an iterative process. Measures to improve building performance, achieve thermal comfort, and protect overheating are identified.