Experimental investigation of buoyancy-driven natural ventilation in a building with an atrium using particle image velocimetry (PIV) method

Abstract

ABSTRACT Natural ventilation is one of the main passive ways to reduce energy needs by delivering fresh air into the building without the help of mechanical systems. In this perspective, using the water bath model and particle image velocimetry, an experimental study of the relationship between fluid velocity caused by buoyancy-driven natural ventilation in a building with single-sided and cross ventilation has been conducted. A case study building with a jointed atrium has been considered for the six initial conditions tests. In the test model which has two low-level inlet openings, fluid velocity in single-sided ventilation mode was meaningfully higher than in cross-ventilation mode, ranging from 18% to 32%. In contrast, by changing the position of the windows to higher levels, cross ventilation creates a flow with 28% higher velocity. Analyzing velocity data demonstrates that, in all tests, the air change rate caused by buoyancy force in cross ventilation mode is more than in single-sided one. Furthermore, in the tests with two high-level openings acting as outlet openings, by opening both sides’ windows in the building, the air change rate increases significantly by 71.75%.