The SPA-TOPSIS-Based Evaluating Approach on Thermal Sensation Model at Different Vane Angles in UFAD-DV System

Under floor air distribution system and displacement ventilation (UFAD-DV) system is used to provide comfortable indoor thermal environment in summer, which largely satisfies overall and local thermal sensation. In UFAD-DV system, the selection of supply vane angle is particularly important to achieve the best thermal comfort. This paper studied thermal sensation of a manikin in sedentary state through the AIRPAK simulations. Firstly, in order to analyze the influence of the local thermal sensation on overall thermal sensation (OTS), the manikin model consisting of five local body parts was constructed. Then, the set pair analysis technique for order preferences by similarity to an ideal solution (SPA-TOPSIS) method was proposed to analyze the overall thermal sensation model and the combination model of overall and local thermal sensation at different supply vane angles. Finally, according to the SPA-TOPSIS analysis, the combination model of overall thermal sensation and local thermal sensation was determined and the best supply vane angle was 10 degrees downward. The PMV and PPD values of each part of the body and overall body were 0.1932, 0.3413, 0.2287, 0.0503, - 0.0992, 0.173 and 5.9721, 7.5005, 6.377, 5.2632, 5.2579, 6.79, respectively. The weight coefficient method was used for the validation of SPA-TOPSIS-based evaluating results with p < 0.05. In addition, the thermal sensation of foot has important impact on thermal sensation, and the ideal integrated thermal sensation of five local body parts and overall body was achieved. The proposed SPA-TOPSIS-based evaluation approach can determine the best supply vane angle, which optimizes the OTS on the premise of satisfying the local thermal sensation.