Thermal Comfort Characteristics and Occupant Expectations in Open Plan Offices - an Investigation in Hot Humid Climate

Experimental studies and subjective evaluation of thermal comfort have been carried out with respect to an open-plan office building located in hot and humid climate of India. Experimental measurements are made using LSI Lastem indoor environmental quality monitoring system. The subjective evaluation follows the ASHRAE Class II protocols. A considerable difference is found between the simulated comfort levels and the perceived comfort levels. A considerable difference is noted in the radiant temperature and illuminance levels across the office space especially between the peripheral zone and the interior zones. Subjective analysis of thermal comfort shows that the Fanger's PMV model predicts higher level of heat discomfort compared to the actual subjective thermal sensation of the occupants. The measured PMV values ranged from 0 to +1 while the subjective votes (TSV) ranged from +1 to -1.5. However it needs to the noted that majority of the subjects view fully glazed façade as an identity for modern office building. Similarly a higher percentage of the respondents are satisfied with the outdoor views available to them irrespective of the glare related discomfort that is caused by the glass façade. The study highlighted the need for a real time performance benchmarking for office spaces in Indian scenario.