Numerical Investigation of the Indoor Environmental Factors With Stratum and Underfloor Air Distribution Systems in an Educational Institute Computer Laboratory

Abstract

Ventilation with optimal airflow patterns is the most significant aspect in controlling airborne transmission as well as providing an improved indoor thermal environment and air quality in an energy-efficient way. Conducting the air-conditioned computer laboratory in educational institutes during the pandemic is challenging. This article presents a comparative study on various aspects related to indoor environmental quality factors, including thermal comfort indices, vertical air temperature differences, draught rate, air distribution effectiveness, CO2 concentration levels, energy saving, and dispersion of exhaled droplets of aerosols in different sizes (0.5 μm, 6 μm, 20 μm, and 45 μm). The study examines these factors by comparing 12 cases with different air distribution strategies (stratum, underfloor), air change rates (15 ACH and 20 ACH), and return outlet positions (1.3 m, 1.8 m, and 2.3 m). The numerical investigation is carried out in the educational institute computer laboratory model with the dimensions of 10 m (length), 5 m (width), and 3 m (height). The findings indicated that stratum ventilation and underfloor air distribution (UFAD) at a rate of 20 ACH, along with the placement of the return outlet in position 2, would ensure adequate ventilation, acceptable thermal comfort, and optimal energy savings. Compared to the overhead air distribution system, the maximum energy savings were obtained at 10.15% and 10.07% in both stratum and underfloor air distribution systems. Furthermore, the higher air distribution index and ventilation parameter were acquired in the UFAD system at 20 ACH. This study provides a better understanding of air distribution systems and aerosol particle dispersion in the indoor environment of a computer laboratory.