Effective Ventilation Parameters and Thermal Comfort Study of Air-conditioned Offices

Abstract

The study presents objective and subjective studies of thermal comfort levels and ventilation characteristics of two air-conditioned postgraduate study offices. The observations were performed at the offices of Department of Electrical and Electronic Engineering, in University Putra Malaysia. Thermal comfort variables were measured while the students answered a survey on their sensation of the indoor climate. Concurrently, tracer gas analysis, based on concentration decay method, is employed to determine air exchange rate, age of air and air exchange effectiveness. During the air conditioner is working, the study offices had not conditions within the comfort zone, of ASHRAE standard 55 causing occupants to report cold thermal sensations and the objective data analysis showed that the offices were uncomfortable. The thermal neutralities were significantly higher that proposed by ASHRAE Standard 55:1992. The monitored air exchange rates are indicated that the provisions of outside air for ventilation based on design occupancy are adequate for these two study offices. In addition, questionnaires were completed by the students in order to provide a subjective assessment of thermal comfort and indoor air quality. Finally, the outcomes of over 30 surveys for each office responses to the thermal comfort questions are presented and discussed.