Thermal performance analysis of a naturally ventilated system using PMV models for different roof inclinations in composite climatic conditions

Abstract

Computational analysis has become a very useful tool for a detailed understanding of building physics before actual building constructions and for predicting such system behaviors where massive urbanizations are envisaged. The present study attempts to describe the efficacies of CFD as an “analysis led design” tool, where a computationally modeled cross-ventilation system with asymmetric positions of openings is analyzed to estimate the comfort zones according to the PMV (predicted mean vote) model for evaluating the influence due to roof inclinations, thereby providing opportunities in rectifying any anomalies pertaining to it, prior to the actual construction. A numerical analysis has been carried out to examine the effects of natural ventilation in a wind-driven system using the established extended PMV model (PMVe). The study focuses on thermal comfort and the effect of roof inclination angle over the three different weather conditions in Delhi—winter season (high humidity and low temperature), summer season (low humidity and high temperature) and monsoon season (high humidity and mild temperature). Appropriate roof inclination angles provide a better ventilation rate and air distribution pattern, which significantly affects comfort condition. Study shows that for winter season, the PMV values decrease as the roof inclination angle is increased and the ventilation rate for 30° inclined roof increases about 16% as compared to the flat roof case, while PMV values increase with roof inclination for summer season, signifying zone of discomfort. It also concludes that a moderate roof inclination is beneficial for monsoon season.