Impact of eave and roof pitch on cross ventilation for an isolated building with sawtooth roof

Lip Kean Moey; Seng Keat Cheong; Md Akkik Al Zobaied; Vin Cent Tai; Tze Fong Go; Perk Lin Chong

doi:10.15282/jmes.17.2.2023.6.0750

Authors

Lip Kean Moey Centre for Modelling and Simulation, Faculty of Engineering, Built Environment & Information Technology, SEGi University, 47810, Selangor, Malaysia. Phone: 03-6145 1777; Fax.: 03-6145 1666
Seng Keat Cheong Faculty of Engineering, Built Environment & Information Technology, SEGi University, 47810, Selangor, Malaysia
Md Akkik Al Zobaied Faculty of Engineering, Built Environment & Information Technology, SEGi University, 47810, Selangor, Malaysia
Vin Cent Tai Centre for Modelling and Simulation, Faculty of Engineering, Built Environment & Information Technology, SEGi University, 47810, Selangor, Malaysia
Tze Fong Go Centre for Advance Materials and Intelligent Manufacturing, Faculty of Engineering, Built Environment & Information Technology, SEGi University, 47810, Selangor, Malaysia
Perk Lin Chong School of Computing, Engineering & Digital Technologies, Teesside University, Middlesbrough, TS1 3BX, United Kingdom

DOI:

https://doi.org/10.15282/jmes.17.2.2023.6.0750

Keywords:

eave inclination, roof pitch, cross ventilation, CFD, ventilation rate

Abstract

An eave refers to an extension attached to the building roof to protect the interior space from direct solar radiation and improve the performance on cross ventilation. In this study, the impact of eave inclination angle and roof pitch of an isolated sawtooth roof building on cross ventilation were investigated. The eave configurations at either windward or leeward openings were included. 3D steady Reynolds-Averaged Navier-Stokes (RANS) equation in combination with the Shear-Stress Transport model (SST k-ω model) was used for the Computational Fluid Dynamics (CFD) simulations. Grid sensitivity study was carried out and the performance of cross ventilation was evaluated based on the non-dimensional velocity magnitude, spatial distribution of pressure coefficient as well as the ventilation rate of the building. For the simulation model with 55° roof pitch, it is observed that a region with high velocity magnitude formed on top of the leeward eave due to the higher roof pitch and presence of the leeward eave. Results also indicated that the building model with 90° leeward eave and 55° roof pitch has the highest increment in ventilation rate which is 7.16%. On the other hand, the building model with 90° windward eave has the highest pressure coefficient because more blockage of airflow is caused by a steeper roof as the roof pitch of the building increases. Furthermore, the building model with 90° leeward eave shows a larger region with negative pressure at the leeward façade indicating higher airflow leaving the leeward opening. Therefore, the airflow behavior and characteristic are both dependent on the roof pitch and eave inclination angle for a naturally ventilated building.

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