Thermal Comfort - CBE Model

The Centre has developed a more advanced model for understanding and determining occupant thermal comfort for the Built Environment (CBE). Focusing on the complex relationships between environmental conditions and our physiological response to them, the CBE Model relates thermal comfort to the principles of human thermal regulation instead of just external variables.

To differentiate local thermal comfort levels, such as at the head, chest, arms, and legs, a thermal manikin is used to predict thermal sensation indices similar to the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) models.

The primary difference between the CBE model and the Predicted Mean Vote (PMV) and the Predicted Percentage of Dissatisfied (PPD) models is the differentiation of comfort as positive or negative. Unlike the measure of hot or cold experience based on six key variables, the CBE model provides an absolute explicit level of the thermal state, combining both thermal comfort and thermal sensation.

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The benefit of this method can be seen above, showing interior window surface temperature and its impact on an occupant sitting 1 meter from the window. As the glazing temperature increases above or below 25 ° C, the CBE Thermal Comfort Model is more responsive than Predicted Mean Vote (PMV) to the changes in glazing temperature and its effects on thermal sensation. As such, it can better predict local discomfort caused by the window.