Investigation into effect of non-uniform thermal environment on thermal sensation under stratum ventilation for heating by using interpolation-based multi-level fuzzy comprehensive evaluation

Abstract

Stratum ventilation for heating is applied to provide satisfactory indoor thermal environments with great potentials in winter. Indoor non-uniform environments are important for both overall and local thermal sensations in the same occupied subzone (i.e., vertical spaces) as well as different subzones of the occupied zone (i.e., horizontal spaces) under the effect of supply air jets. This study carried out field chamber experiments to consider the effect of non-uniform environments on both overall and local thermal sensations under stratum ventilation for heating using the multi-level fuzzy comprehensive evaluation (MFCE) method. This method has a multi-level structure to simultaneously investigate thermal sensation in both vertical spaces and horizontal spaces. The interpolation models of thermal sensation are helpful to enlarge the experimental sample size investigated by MFCE. The results showed that the interpolation-based MFCE method can quantitatively analyze the effect of non-uniform environments on thermal sensation in different subzones of the occupied zone from vertical spaces and horizontal spaces under the effect of supply air parameters. Compared with supply air temperature, supply air velocity has the opposite influence on the variation range of both integrated thermal sensations of feet, head and overall body and local thermal sensation of feet between the occupied subzones 1 and 2. Supply air temperature and velocity of 25–27 °C and no less than 1.1 m/s were recommended to improve the non-uniformity of thermal environments.