PMV based assessment for Summer Thermal Comfort in Sub Tropical, Temperate and Mountain regions of Nepal

The design and load calculation of Heating Ventilation and Air Conditioning (HVAC) system is done to bridge the gap between atmospheric and occupant desired thermal comfort level. American Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE) established Predicted Mean Vote (PMV) scale is the internationally adopted metric to determine thermal comfort. The PMV method provides a comprehensive assessment of thermal comfort by considering factors such as air temperature, humidity, air velocity and clothing insulation. While previous studies have calculated comfort temperature using Griffith’s method, they lack in establishment of national baseline scenario for thermal comfort in Nepal. This study examines summer thermal comfort in the Sub Tropical (Terai), Temperate (Hilly) and Mountain (Himalayan) regions using the PMV method and quantifies the national thermal comfort scenario. Likewise, concurrent to PMV measurement, questionnaire survey was conducted to gather the subjective thermal comfort sensation. This makes the study more novel and nuanced in the context of Nepal. While the overall trends in PMV values and survey responses align, we observed discrepancies at a detailed level (variability of +1 for Sub Tropical, ∼+0.5 for Temperate and ∼+0.1 for Mountain Region). These differences may be attributed to thermal acclimatization and regional climate adaptation. Hence, this study contributes valuable insights into the summer thermal comfort preferences of people across different climatic regions in Nepal.