Predicting the thermal comfort of occupants in an indoor auditorium space with different UFAD ventilation arrangements

Abstract

An “Underfloor Air Distribution” (UFAD) system employs the open area underneath a raised floor system to drive conditioned air to the supply outlets situated in the floor. To understand a UFAD, think of it as an “upside-down version” of an overhead (OH) system. The idea behind it is to increase both energy efficiency as well as the quality of air in a home. In this paper, an auditorium model has been simulated for analysing the temperature distribution as well as thermal comfort of human occupants provided with 4 different cases of ventilation. The auditorium has two AC inlets ducts, each 2.50 m wide further branched into a number of small diffusers over the auditorium ceiling in order to distribute the inlet air evenly throughout the theatre space. The first case involves an upward ceiling outlet at the front of the theatre near the screen area while the second case has a downward outlet on the floor in the screen area. The third case is similar to the second one with human occupants designed as cuboids on every staircase while for the fourth case, the outlets have been provided under every seat on the staircase. It has been observed in the analysis that the downward outlets in case 2 provide better temperature distribution than the upward outlets of case 1. But the position of outlets below every seat, as in case 4, in the auditorium provides the best thermal comfort for the occupants than all the other cases. Hence, for the “maximum thermal comfort” of the human occupants, the outlets are advised to be installed downward on the floor under every seat.