Fishbone vs. peripheral-ring air-conditioning layouts: Spatial thermal variation and occupant comfort in office environments

This study investigates the effect of distinct air-conditioning (AC) layouts on occupant thermal comfort in a high-performance open-plan office building in Taichung, Taiwan. The research compared two floors: one with a peripheral-ring AC system (9th floor) and the other with a fishbone-type system (11th floor). Field measurements and occupant surveys were used to assess thermal environments and subjective perceptions. Results show that the fishbone configuration produced significantly greater temperature variation (up to 3.5 °C throughout the day), indicating larger microclimatic variability. Statistical analysis revealed a significant interaction: high perceived wind speed led to drier air perception, while low wind speed was associated with dampness. GLM analysis confirmed that individual factors (e.g., male, 36-40 age group) and behavioral adjustments (e.g., clothing change, seat switching) were negatively correlated with comfort. In conclusion, AC configuration strongly impacts indoor thermal uniformity and comfort. Effective HVAC design requires consideration of localized thermal variations, individual characteristics, and behavioral adaptation.