Thermische Behaglichkeit - Unterschiede zwischen frei und mechanisch belüfteten Gebäuden aus Nutzersicht

At present a lack of guidelines for the design of thermal comfort in naturally ventilated office buildings leads to uncertainty when planning such buildings in Germany. The present work was carried out in order to identify differences in the perception of thermal comfort of office workers in naturally ventilated and air-conditioned buildings. It is based
on both subjective data from interviews as well as on objective data from physical measurements. The analysis includes data collected in 14 German office buildings from the ProKlimA-Survey. The analysis of the interviews shows that occupants in naturally ventilated office buildings are significantly more often satisfied with their thermal environment than occupants in
air-conditioned buildings. Several non-thermal parameters influence thermal comfort. The impact of the non-thermal variables depends on the type of ventilation and the perception of the indoor environment temperature (hot or cool).
In the literature it is mentioned that occupants in naturally ventilated offices accept a wider range of indoor temperatures than occupants in air-conditioned offices. The bandwidths of temperature found in the present work are the same for both types of ventilation. Relevant literature comprises four major approaches. On the one hand there is the PMV-Model by Fanger and its modification by Mayer. On the other hand there are two adaptive approaches: a Dutch guideline and the ASHRAE approach.
Both adaptive approaches determine the indoor comfort temperature dependent on a mean outdoor temperature.
The suitability of the four approaches for assessing and predicting thermal comfort in naturally ventilated and air-conditioned offices was investigated. The closest agreement between predictions and interviews for air-conditioned
offices is achieved by Mayer’s modification of the PMV-Model. For naturally ventilated offices the ASHRAE approach shows the best match.
So far Fanger's PMV-Model is the standardized method to assess thermal comfort in Germany and Europe. The results demonstrate that new guidelines
for assessing and planning of thermal comfort in office buildings are required for both natural ventilation and air-conditioning.