| Ventilation is air circulation inside a building. Two main approaches can be applied for building ventilation: (1) a fan is used to drive the airflow, and (2) natural convection due to temperature difference is used to drive the airflow. The cost of electricity on ventilation is significant, especially when it is considered together with space cooling. The second approach can take advantage of the renewable resource such as solar energy to decrease energy cost.;To provide ventilation as well as thermal comfort, a passive ventilation system combined with the solar chimney and earth tube is presented. By using the numerical method, the ventilation performance of the solar chimney and earth tube is investigated. The commercial software package, Fluent, is adopted to build the model.;The effects of solar chimney height, air gap width as well as the brick width are investigated. It is found that the flow rate increases by 100% as the chimney height increases from 1.5 to 3 m, while the air gap width has much smaller influence. It is also shown that the solar chimney works on different seasons although the solar radiation changes significantly. In addition, using an unsteady state model, it could be observed that the chimney with 0.3 m thick brick wall can work the whole day even in the night.;The effects of the earth tube length, width, and buried depth are presented. Multiple tubes in series/parallel connection are also investigated. It shows that the tube with 10 m length and 0.3 m width will cool the 30 °C ambient air to 25 °C at 0.3 m3/s flow rate. The tube length and buried depth are shown more influence on the thermal performance than the tube width. The multiple tubes in both connections are also show better performance than the single tube.;The ventilation of building with solar chimney and earth tube is presented. By using a 7 m height solar chimney and 20 m length earth tube, the room temperature is about 23 °C dropped from ambient temperature 30 °C, while the ventilation rate is 0.068 m3/s. |
