Diurnal Thermal Comfort Variations and Model-User Perception Gaps in a Tropical Peatland Campus

This study investigates the diurnal variation of outdoor thermal comfort and the discrepancy between the Predicted Mean Vote (PMV) and the Thermal Sensation Vote (TSV) in a humid tropical campus environment. The research was conducted at Lambung Mangkurat University, located in a wetland area with dense tropical vegetation. Data collection combined microclimatic measurements—air temperature, relative humidity, wind speed, and solar radiation—with thermal perception surveys administered to 150 students during two time intervals: 11:00–12:00 and 15:00–16:00 over five days. The purpose of this study is to evaluate the diurnal variation in thermal comfort and examine the discrepancy between model-predicted and user-perceived sensations. The novelty of this study lies in its integration of objective PMV calculations with subjective TSV responses in a tropical peatland context, revealing critical model limitations and informing adaptive design strategies. Results indicate that midday PMV values ranged from +0.88 to +1.30, exceeding ASHRAE-defined comfort thresholds and reflecting “warm to slightly hot” conditions. In the afternoon, PMV values dropped to a more neutral range (0.00 to +0.50). However, TSV responses revealed greater discomfort, particularly at midday, with most respondents reporting sensations from “slightly warm” to “warm” (TSV +1 to +2). This indicates a notable gap between model predictions and actual user perceptions. These findings highlight limitations of the PMV model in representing outdoor comfort in humid tropical contexts and suggest the need for locally adapted or adaptive-based models. Recommendations include implementing time-sensitive design strategies, increasing effective vegetative shading in active areas, and incorporating semi-permanent architectural elements such as pergolas and porous canopies. Such interventions support climate-responsive campus design and contribute to sustainable development goals in tropical higher education settings. Keywords: thermal comfort; predicted mean vote; thermal sensation vote; tropical campus; outdoor microclimate.