Comparison of Thermal Comfort Condition of Naturally Conditioned Semi-Outdoor, Courtyard and Indoor Air-Conditioned Spaces in Tropical Climate

Abstract

Universiti Tun Hussein Onn Malaysia library is in the tropical climate of Malaysia and has a distinctive feature of the circular courtyard and semi-outdoor spaces for practical public spaces and energy saving. This study was conducted on the ground level of the library which consists of an open terrace consisting of a cafeteria, a garden in the circular courtyard and an air-conditioned seminar room. This study aimed to compare the thermal comfort condition of these spaces through physical and subjective measurements. Physical measurement was conducted for air temperature, relative humidity, air velocity and mean radiant temperature at the two selected sampling points on each investigated area positioned at 0.6 meters from the floor. Data were collected for three days in each area during two periods of time; 9 to 11 am and 2 to 4 pm. Subjective measurements were also collected through the distributed questionnaire to 150 respondents to determine the thermal sensation votes (TSV) of each investigated area. Calculation based on physical measurement showed the thermal comfort for both cafeteria and garden were within 90% thermal comfort acceptability limit. PMV value for the air-conditioned seminar room was -0.45 with PPD value of 9.03%. Both results complied with the ASHRAE 55 Standards for the acceptable condition for both naturally and air-conditioned spaces.  Meanwhile the averaged TSV values at the cafeteria, garden and seminar room were +0.40, +0.12 and -0.36 respectively. Results of the study concluded that respondents perceived a higher comfort temperature range in the courtyard and cafeteria compared to indoor air-conditioned spaces, but still within the recommended range of ASHRAE 55 standard. The results of the study showed that semi-outdoor places can potentially be designed as practical public spaces for comfortable and sustainable spaces.