Air change rates driven by the flow around and through a building storey with fully open or tilted windows: An experimental and numerical study

Abstract Air change rates (ACH) through open and tilted windows in rooms of residential buildings driven by atmospheric motions are investigated to evaluate natural ventilation concepts. Model experiments in wind tunnels, numerical flow simulations (CFD) and thermal building simulations are used. Pressure profiles are measured on the facade of a building model for selected wind directions and velocities. A separated sample storey and a sample single room in larger scales were used to measure air transport through window openings under the influence of the external pressure distribution. The ACH was obtained by velocity measurements in the window cross sections and by tracer gas measurements using the decay method. ACH from CFD computations of the wind tunnel environment agreed well with the experimental values. Therefore the numerical simulations were extended to real dimensions. The dependency of the ACH on the position in the external flow field and a scaling law for the ACH are presented. The wind-driven ACH obtained are much larger than the temperature-driven values prescribed in the Austrian standard O-NORM B 8110-3 on the prevention of high room temperatures during summer. A comparison of the impact of temperature-driven with wind-driven ACH, i.e. natural ventilation concepts, in thermal building simulations is presented.

[1]  Takashi Kurabuchi,et al.  Study on airflow characteristics inside and outside a cross-ventilation model, and ventilation flow rates using wind tunnel experiments , 2001 .

[2]  Nikos Nikolopoulos,et al.  Characterization and prediction of the volume flow rate aerating a cross ventilated building by means of experimental techniques and numerical approaches , 2011 .

[3]  Tine Steen Larsen,et al.  Natural Ventilation Driven by Wind and Temperature Difference , 2006 .

[4]  David S.-K. Ting Ventilation and Airflow in Buildings: Methods for Diagnosis and Evaluation , 2008 .

[5]  Qingyan Chen,et al.  Natural Ventilation in Buildings: Measurement in a Wind Tunnel and Numerical Simulation with Large Eddy Simulation , 2003 .

[6]  Andreas K. Athienitis,et al.  Wind Driven Flow through Openings – A Review of Discharge Coefficients , 2004 .

[7]  Alireza Afshari,et al.  Numerical predictions of the discharge coefficient of a window with moveable flap , 2012 .

[8]  Per Heiselberg,et al.  Characteristics of Airflow from Open Windows , 2001 .

[9]  Markus Rösler,et al.  Calculation of wind-driven cross ventilation in buildings with large openings , 2006 .

[10]  Ursula Eicker,et al.  Controlled natural ventilation for energy efficient buildings , 2013 .

[11]  Guglielmina Mutani,et al.  Experimental and theoretical analysis of natural ventilation by windows opening , 2002 .

[12]  Maria K. Koukou,et al.  Natural cross-ventilation in buildings: Building-scale experiments, numerical simulation and thermal comfort evaluation , 2008 .

[13]  Atila Novoselac,et al.  Cross ventilation with small openings: Measurements in a multi-zone test building , 2012 .

[14]  Walter Meile,et al.  Flow around and through a building storey with fully opened or tilted windows , 2013 .

[15]  Leon R. Glicksman,et al.  Design analysis of single-sided natural ventilation , 2003 .

[16]  Andreas K. Athienitis,et al.  Wind-induced natural ventilation analysis , 2007 .

[17]  Helmut Sockel AERODYNAMIK DER BAUWERKE , 1984 .

[18]  Konstantinos-Stefanos Nikas,et al.  Experimental and numerical investigation of the tracer gas methodology in the case of a naturally cross-ventilated building , 2012 .

[19]  Monika Hall Untersuchungen zum thermisch induzierten Luftwechselpotential von Kippfenstern , 2004 .

[20]  Elena G. Dascalaki,et al.  Predicting single sided natural ventilation rates in buildings , 1995 .

[21]  Nikos Nikolopoulos,et al.  Numerical study of a naturally cross-ventilated building , 2010 .

[22]  Michael Wetter,et al.  Multizone Airflow Model in Modelica , 2006 .

[23]  Cb Christof Gromke Einfluss von Bäumen auf die Durchlüftung von innerstädtischen Straßenschluchten , 2009 .

[24]  Nicholas John Cook,et al.  The Designer's Guide To Wind Loading Of Building Structures , 1986 .

[25]  Andreas Bott,et al.  Dynamics of the Atmosphere: A Course in Theoretical Meteorology , 2003 .

[26]  G. Evola,et al.  Computational analysis of wind driven natural ventilation in buildings , 2006 .

[27]  Bodo Ruck,et al.  Die Simulation atmosphärischer Grenzschichten in Windkanälen , 2005 .

[28]  Girma Bitsuamlak,et al.  Wind-driven natural ventilation in a low-rise building: A Boundary Layer Wind Tunnel study , 2013 .

[29]  J. Counihan,et al.  An improved method of simulating an atmospheric boundary layer in a wind tunnel , 1969 .

[30]  J. Counehan,et al.  Wind tunnel determination of the roughness length as a function of the fetch and the roughness density of three-dimensional roughness elements , 1971 .

[31]  Mohamed B. Gadi,et al.  A comparison between CFD and Network models for predicting wind-driven ventilation in buildings , 2007 .

[32]  Per Heiselberg,et al.  Single-sided natural ventilation driven by wind pressure and temperature difference , 2008 .

[33]  Chia-Ren Chu,et al.  Wind-driven cross ventilation with internal obstacles , 2013 .

[34]  O. G. Martynenko,et al.  Handbook of hydraulic resistance , 1986 .