Abstract | In this review, we assessed the validity of two commonly used thermal comfort models. The first, Fanger's Predicted Mean Vote (PMV) Model, combines four physical variables (air temperature, air velocity, mean radiant temperature, and relative humidity), and two personal variables (clothing insulation and activity level) into an index that can be used to predict the average thermal sensation of a large group of people. The second, Fanger's Draught Model, predicts the percentage of occupants dissatisfied with local draught, from three physical variables (air temperature, mean air velocity, and turbulence intensity). Our review indicated that the PMV model is not always a good predictor of actual thermal sensation, particularly in field study settings. Discrepancies between actual and predicted thermal sensations reflect, in part, the difficulties inherent in obtaining accurate measures of clothing insulation and activity level. In most practical settings, poor estimations of these two variables are likely to reduce the accuracy of PMV predictions. Our review also suggested that the bias in PMV predictions varies by context. The model was a better predictor in air-conditioned buildings than naturally ventilated ones, in part because of the influence of outdoor temperature, and opportunities for adaptation. |
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