Thermal Comfort Assessment Based on Measurement and Questionnaire Surveys in a Large Mechanically Ventilated Space

Abstract

This paper presents a thermal comfort study in a large occupied office (floor-to-ceiling height >5m) ventilated by a simple mixing ventilation system. The evaluation was conducted during the summer seasons of 2016 and 2017 using three different tools; (a) long term monitoring, (b) short term detailed measurements and (c) occupant questionnaire. Long term monitoring included air temperature and relative humidity at several locations and heights within the space with external conditions retrieved form a weather station on the roof of the building. The short term spot measurements included air temperature, relative humidity and air speed each at three vertical occupancy heights and the inlet diffusers. The surveys involved collection data using questionnaires developed based on ISO 10551. Analysis of long term data using temperature clouds indicate that the building can be approximated to be free running. A comparison between the measurement (analysed using PMV/PPD and adaptive thermal comfort) and the questionnaire surveys’ results show good agreement between predictions and occupant evaluation. The existing ventilation system was able to meet the requirement for thermal comfort in this large enclosure. However, with regards to the air movement, it did not achieve the recommended levels and this has affected occupant responses.