Thermal pleasure in built environments: spatial alliesthesia from air movement

In recent years there has been a shift in research focus away from the negative effects of draught towards the positive benefits of air movement, particularly in the context of personal environmental control (PEC) systems. Thermal perception under targeted air movement is different from exposures in airflow uniformly distributed across the body, but is less well understood. Specification of performance criteria for PEC systems remains unresolved, as there are no clear conclusions regarding optimum target area, velocity ranges or patterns of velocity dynamics. This paper examines the effects of different local air-velocity profiles on thermal sensation and thermal pleasure experienced by human subjects near the upper boundary of the comfort zone, and interprets the findings within the theoretical framework of spatial alliesthesia. It was found that positive thermal pleasure can be achieved when contrasting relationships between local and global skin temperatures trends are established. The substantial body of research literature on local thermal discomfort can be coherently interpreted within the theoretical framework of spatial alliesthesia; local discomfort represents thermal alliesthesia with the incorrect polarity between local and global thermal states. Spatial alliesthesia therefore provides a conceptual framework to understand PEC systems and their potential to minimize occupant thermal dissatisfaction.