Numerical simulation of thermal flow and comfort in an office room

Abstract

In this study, airflow and temperature fields in an office room with a table and a sitting person are computed to predict the thermal comfort by means of percent dissatisfaction (PD). The office room is ventilated with a wall type air conditioning unit for winter condition and the flow is considered to be turbulent, steady, incompressible, and two-dimensional. Governing equations are solved by using commercial computational fluid Dynamics (CFD) code of ANSYS15 Fluent. Firstly, grid independency study is evaluated by using Standard k-ε (Std. k-ε) model with standard wall function approach, and then five RANS based two-equations turbulence models and near-wall modelling approaches are compared and validated by using well-known Annex20 test room. Although all k-ε based models exhibit similar performance, Std. k-ε model with std. wall function approach was preferred due to common usage and its numerical robustness. Computations are performed for nine different cases including three different inlet velocities (1.5, 2.0, and 3.0 m/s) and three different inlet temperatures (298, 300, and 303 K). Dissatisfied space increases with increasing inlet velocity for a specified inlet temperature, and decreases with decreasing temperature for a specified inlet velocity.