Thermal Comfort Measurements in a Hybrid Ventilated Office Room

SUMMARY Global climatic warming trends are becoming more and more obvious. They are characterized by longer and more intense heat wave periods as witnessed in extreme by the summers 2003 and 2006. This situation asks for mechanical cooling applications in office buildings. Is it possible to reach good indoor environmental conditions using hybrid ventilation strategies only? This question has been investigated by measurements in the Forum Chriesbach, a new low energy office building located in Dubendorf, Switzerland. The ventilation concept of this building is based on an earth-to-air heat exchanger system for hygienic air supply during daytime and a passive night cooling strategy by stack ventilation through window openings in the facade and towards a large atrium with roof outlets. Outdoor and indoor climatic conditions as well as internal heat loads have been measured in an office room over the summer heat wave period 2006. The measured data shows, that the hybrid ventilation system is able to hold the operative room temperatures during the heat wave period 2006 in the acceptable comfort range of ±0.5 PMV and to meet the requested indoor air quality limits (CO2 < 1000 ppm). It thus confirms the thermal simulation results made by the project design team.