Highway to the Comfort Zone: History of the Psychrometric Chart

The psychrometric chart is the most common data visualization technique for the designers of thermal comfort systems worldwide. From its humble roots as means of expressing the characteristics of air in building systems design, the use of the chart has grown to include the representation of the zones of human thermal comfort according to both conventional and adaptive models. In this paper, we present an extensive history of this development and the fallacies with representing comfort simply as a box that sometimes moves on the chart. The origins of the link between refrigeration control and comfort control are examined through archival reviews, examining the works of Carrier, Yagoglou, and their contemporaries in the context of modern comfort mischaracterizations. A clearer understanding of the mapping of comfort, control, and climate metrics with psychrometrics is reported, and a critique of the conflation is reported to increase awareness of the limitations of such treatment of these three critical domains.