Comparative evaluation of natural ventilated and mechanical cooled non-residential buildings in Germany: Thermal comfort in summer

This paper presents a detailed analysis of thermal comfort in summer for 19 lowenergy non-residential buildings in Germany, applying the comfort standard EN 15251:2007-08. The study aims to propose (1) a methodology for the evaluation of thermal comfort, (2) to discuss redefined constraints for the thermal comfort standard EN 15251:2007-08, (3) to analyze the thermal comfort, and (4) to assign the buildings studied to three comfort classes I, II and III. In summer, eight buildings employ a nighttime ventilation concept in order to condition the building. The other 10 buildings use geothermal energy (ground and ground water) as environmental heat sinks to cool the buildings via thermo-active building systems (TABS). For comparison, one building is air-conditioned. A method is proposed to determine and evaluate thermal comfort in a building. It is suggested, to present the time of occupancy, where 84 % of the building area complies with comfort class I, II, and III. There fore, each building with its energy concept for heating, cooling, and ventilation gets its individual thermal comfort footprint.