抄録
We have tried to predict thermal sensation by using of thermo-regulation model, but the prediction was limited to physiological response. PMV or SET* are used as method to predict thermal sensation, but these are applicable to only uniform thermal environment and not able to predict the thermal sensation in non-uninform thermal environments. Zhang proposed a predicting model for local thermal sensation, but the sensitivity of thermal sensation to the operative temperature is not examined.
In this study we propose a new predicting model OTn based on Zhang model for local thermal sensation under non-uninform thermal environments.
OTn model is proposed for the local thermal sensation with ASHRAE seven-point scale under non-uniform thermal environments. To develop the prediction model, the subject experiments in the climate chamber was conducted under the thermal conditions from cold side to hot side. The local thermal sensations to the operative temperature under steady states are predicted by the proposed model and original Zhang model respectively, and compared with the measured values. As a result of examinations, there were three issues.
(1) Gap of set-point temperatures
(2) The prediction trend is different according to the amount of clothing
(3) Deterioration of prediction accuracy in high temperature condition
Therefore it was necessary to introduce changing neutral skin temperature, supplementary skin temperature considered latent heat load and correction term considered the amount of clothing into Zhang model. So we added three improvements.
(1) Changes to the set-point temperatures in which the amount of clothing and metabolic rate are considered.
(2) Skin temperature is corrected by the latent heat load.
(3) Addition of term where material and ventilation of clothes are considered
It was found the accuracy of the predicted local thermal sensations in the hot environment using OTn model is much improved compared to the predicted value using Zhang model on the whole.
To validate the new prediction model, it was tested with the Nilsson's subjective experimental results. The experiments were executed in a vehicle cabin and the environmental condition in summer and winter. To verify accuracy, we compared results of local thermal sensation and prediction result by the new model and Zhang model. The prediction accuracy on Head and under the hot environment were improved in particular compared with original Zhang model
We developed OTn model which predicts the local thermal sensation with the use of the thermo-regulation model JOS-2. In developing OTn model, we incorporated the elements of the latent heat loss in the thermal sensation prediction equation, and the method of setting the set point temperature was changed. As a result, we confirmed that accuracy of prediction using OTn model has been improved compared to the previous model.
