Revisiting an old hypothesis of human thermal perception: Alliesthesia

Many new technologies and approaches to the provision of comfort inside buildings such as displacement ventilation, mixed-mode strategies, personally controllable (task-ambient) designs, chilled beams as well as some old but recently fashionable ones such as natural ventilation are prompting a rethink of the accepted comfort wisdom. How can a single combination of thermal environmental parameters be deemed unacceptable in a conventional heating ventilation and air-conditioning setting, and yet be regarded as acceptable, or even pleasant, in a naturally ventilated or mixed-mode setting? Why do current comfort standards prescribe static and isothermal conditions for comfort in one building, and dynamic and spatially variable indoor climates for comfort in another? The phenomenon of alliesthesia is used to differentiate thermal pleasure from thermal neutrality and acceptability. Alliesthesia is proposed as the logical framework of a new approach to thermal comfort modelling, building on the solid foundation of multi-node physiological models currently available in the literature.