Enhanced Single-Sided Ventilation with Overhang in Buildings

Abstract

Abstract:Enhancing the ventilation performance of energy-efficient buildings with single-sided openings is important because their ventilation performance is poor and strongly depends on the wind conditions. We considered an overhang as a potential building façade for improving the single-sided ventilation performance. We performed numerical simulations of three-dimensional unsteady turbulent flows over an idealized building with an overhang in order to investigate the effect of the overhang on the ventilation performance. Parametric studies were systematically carried out where the overhang length, wind speed, and wind direction were varied. The numerical results showed that the overhang drastically enhanced the ventilation rate in the windward direction regardless of the wind speed. This is because, for windward cases, the overhang produces a vortex with strong flow separation near the tip of the overhang, which promotes a net airflow exchange at the entrance and increases the ventilation rate. However, the ventilation rates for the leeward and side cases are slightly decreased with the overhang. Using an overhang with single-sided ventilation greatly reduces the local mean age of air (LMA) in the windward direction but increases it in the leeward direction.

Elevational Earth-Sheltered Buildings with Horizontal Overhang Photovoltaic-Integrated Panels—New Energy-Plus Building Concept in the Territory of Serbia

“…One more review paper (for different types of shading devices for windows [24]) was published in 2014. Two interesting papers [25,26] were published in 2016. In [25], the use of overhangs as a potential building facade for improving single-sided ventilation performance was analyzed.…”

“…Two interesting papers [25,26] were published in 2016. In [25], the use of overhangs as a potential building facade for improving single-sided ventilation performance was analyzed. The influence of horizontal overhangs (HOs) and glazing with special spectral radiative properties on the annual thermal balance of buildings, as well as the thermal and visual comfort of the users, is presented in [26].…”

Effect of Summer Ventilation on the Thermal Performance and Energy Efficiency of Buildings Utilizing Phase Change Materials

“…In addition, the direct natural ventilation may bring in polluted air and noise from outside to affect the indoor environment. In this case, using mechanical means to assisted ventilation can ensure good indoor air quality [20]. In places where the cooling load exceeds 40 W/m 2 mechanical ventilation can also increase air flow locally and enhance heat transfer.…”