CFD investigation of temperature distribution, air flow pattern and thermal comfort in natural ventilation of building using solar chimney Maher Dhahri Department of Horticultural Systems Engineering and Natural Environment, High Institute of Agronomy of Chott Mariem, Sousse University, Sousse, Tunisia and Department of Physics, Laboratory of Energy and Materials (LabEM), High School of Sciences and Technology of Hammam Sousse, Sousse University, Hammam Sousse, Tunisia, and Hana Aouinet Higher Private School of Engineering and Applied Techniques (IHE-ESPITA), Sousse, Tunisia Abstract Purpose – The purpose of this study is to investigate air flow, temperature distribution and thermal confort in natural ventilation induced by solar chimney for different operating. Design/methodology/approach – Numerical simulation is performed using a commercial computational fluid dynamics (CFD) package ANSYS CFX software to understand the effects of air temperature, air velocity and solar heat flux on the performance of the solar chimney and thermal comfort. The comfort level was evaluated using the air diffusion performance index (ADPI) according to ASHRAE (55-210). The flow was investigated at inclination angles 45° solar heat flux 550-750 W/m 2 and in a solar chimney of 1.4 m length, 0.6 m width and 0.20 m air gab. Findings – The numerical results from the present simulation were first validated with experimental data, which was used for the thermal comfort indexes calculation. The obtained results of the analysis showed that the used numerical technique could accurately predict air flow and temperature distribution in natural ventilated building using solar chimney; the air temperature, air velocity and solar heat flux have a significant impact on thermal comfort; the temperature of 19°C with velocity of 0.15 m.s 1 gives the best effective draft temperature (EDT) satisfy ASHRAE (55- 210) criteria that V = 0.35 m.s 1 and EDT range between 1.7 and 1.1. Originality/value – In the present paper, air flow, temperature distribution and thermal comfort inside a room equipped with inclined solar chimney were numerically investigated and analyzed. The commercial CFD package (CFX 15) is used. Calculations are carried out in an empty room without any human or mechanical activity and the numerical results are compared with measurement points. Keywords CFD, Comfort thermal, Naturally ventilated, Solar chimney Paper type Research paper 1. Introduction Solar chimney assures the improvement of air progress in naturally ventilated buildings. Previous papers confirm that higher air velocities can counteract indoor temperature increases by removing sensible and latent heat from the body (Ge et al., 2019; Wua et al., 2019; Jing et al., 2015; Khanal and Lei, 2015; Amori and Mohammed, 2012; Harris and Helwig, 2007; Ho et al., 2009). In the literature, there are many works regarding the advantages of using renewable and clean solar energy in terms of energy necessities, economic impacts and environmental advantage. Mathur et al. (2006) found that there was a tradeoff between the absorber inclinations and stack height. Measurements showed that the optimum absorber inclination angle varies from 408 to 608 depending on the latitude of the place. With comparison to the proposed mathematical model, the authors found an excellent agreement. Jing et al. (2015) presented a solar chimney experience; the experimental results expose that a gap-to-height ratio of 0.5 maximizes the air flow rate through the chimney. Moreover, this work developed a new model to calculate the air flow rate, in particular, for chimneys with large gap-to-height ratios. The idea of using solar energy still attracts research interests because of its potential to save energy, as well as maintain acceptable indoor air quality. Numerical and experimental study of natural ventilation using a solar chimney is presented by Saifi et al. (2012). In this study, the solar chimney angle variation of 30-40°, and the air gap between the absorber plate and glass are used 10, 20 and 30 cm. The results confirm that the width of the air gap has can increase air flow and reach to optimal thermal pull in the chimney angle of 45°. More recently, Ahmed Abdeen et al. (2019) examined numerically and experimentally the efficiency of using an inclined solar chimney to elevate indoor air motion. The solar chimney used is 1.85 m height, The current issue and full text archive of this journal is available on Emerald Insight at: https://www.emerald.com/insight/1708-5284.htm World Journal of Engineering 17/1 (2020) 78–86 © Emerald Publishing Limited [ISSN 1708-5284] [DOI 10.1108/WJE-09-2019-0261] Received 18 September 2019 Revised 1 December 2019 Accepted 27 December 2019 78