Numerical investigation of thermal comfort in an isolated family house under natural cross-ventilation

This study uses Computational Fluid Dynamics (CFD) to predict the thermal comfort and the flow field in an average family house in Iraq under natural cross-ventilation in a hot climate. The study is performed on the effects of different building parameters, such as the inlet openings position, external boundary wall, wind speed and outdoor temperature, furniture and heat loads on the human thermal comfort indices and the flow field. Although the study showed that the flow rate through openings located near the centre of the building is higher and steadier than the flow rate of openings located near the sides of the building, these positions of the openings have only slight effects on the thermal comfort indices at both the seated and the standing levels. It was also observed that the external boundary wall created well-distributed indoor airflow and improved the indoor environment regarding the mean velocity inside the building. Also, increasing the height of the wall by 20% did not offer a noticeable improvement on the mean velocity distribution. This study has also predicted the range of wind temperatures that would allow for all rooms in the building to be of acceptable thermal comfort. The results of the study suggest that acceptable thermal conditions can be maintained with the external wind speeds ranging from 2 to 5 m/s at the temperature of 25°C. In addition, the results showed that the heat dissipated from electrical appliances found in daily life only have a small effect on the thermal comfort indices at both the seated and the standing levels because they use only relatively small amounts of energy, whereas these indices are increased remarkably at these two levels when an additional heat source was operated in conjunction with these appliances. Lastly, no significant differences between the empty building and the furniture-filled building were observed at the two levels when comparing the air velocity, temperature, and thermal comfort indices.