CO2 tracer gas concentration decay method for measuring air change rate

The measure of air change rate (ACR) in building is a difficult and usually expensive task. The tracer gas method is the reference technique but its implementation is difficult and the interpretation of results is not straightforward. In the present work, the concentration decay method by multiple CO2 transmitters is experimentally validated in the case of cross-ventilation. It is observed that in-situ CO2 transmitters lead to ACR values in good agreement with reference measurements obtained from mechanically controlled values. Whereas multiple transmitters in different sampling positions show the imperfect mixing, a sensor located at the outlet or an averaged value of all sensors can provide an accurate measure of the ACR. Moreover, the spatial variation of CO2 concentration can be used to assess the ventilation efficiency in the test chamber. Different measures and calculation methods are discussed, and the uncertainty analysis of each method is carried out.

[1]  Christian Ammon,et al.  Air exchange rate measurements in naturally ventilated dairy buildings using the tracer gas decay method with 85Kr, compared to CO2 mass balance and discharge coefficient methods , 2013 .

[2]  Mats Sandberg,et al.  A quantitative estimate of the accuracy of tracer gas methods for the determination of the ventilation flow rate in buildings , 1985 .

[3]  Z. Buliński,et al.  Experimentally validated CFD analysis on sampling region determination of average indoor carbon dioxide concentration in occupied space , 2014 .

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

[5]  Hiroyasu Okuyama,et al.  Uncertainty analysis and optimum concentration decay term for air exchange rate measurements: Estimation methods for effective volume and infiltration rate , 2012 .

[6]  Tao Lu,et al.  A novel methodology for estimating space air change rates and occupant CO2 generation rates from measurements in mechanically-ventilated buildings , 2010 .

[7]  K. Pavlou,et al.  Experimental investigation of the air flow and indoor carbon dioxide concentration in classrooms with intermittent natural ventilation , 2008 .

[8]  M. Sherman.  Tracer-gas techniques for measuring ventilation in a single zone , 1990 .

[9]  Man Pun Wan,et al.  Ventilation performance measurement using constant concentration dosing strategy , 2004 .

[10]  T. Boulard,et al.  Natural Ventilation of a Greenhouse with Continuous Roof Vents: Measurements and Data Analysis , 1995 .

[11]  Hwataik Han,et al.  Tracer gas experiment for local mean ages of air from individual supply inlets in a space with multiple inlets , 2011 .

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

[13]  Daniel Berckmans,et al.  Data-based mechanistic modelling approach to determine the age of air in a ventilated space , 2006 .

[14]  Dominique Marchio,et al.  Full scale experimental study of single-sided ventilation: Analysis of stack and wind effects , 2011 .

[15]  K.W.D. Cheong.  Airflow measurements for balancing of air distribution system — tracer-gas technique as an alternative? , 2001 .

[16]  David T. Grimsrud,et al.  AIR INFILTRATION MEASUREMENT TECHNIQUES , 1980 .

[17]  Dominique Marchio,et al.  Development of a new correlation for single-sided natural ventilation adapted to leeward conditions , 2013 .

[18]  Mattheos Santamouris,et al.  An integrated evaluation study of the ventilation rate, the exposure and the indoor air quality in naturally ventilated classrooms in the Mediterranean region during spring. , 2015, The Science of the total environment.

[19]  M. Sandberg,et al.  Building Ventilation: Theory and Measurement , 1996 .

[20]  A. H. Howland,et al.  MEASUREMENTS OF AIR MOVEMENTS IN A HOUSE USING RADIOACTIVE TRACER GAS , 1960 .

[21]  Dries Berckmans,et al.  Influence of sampling positions on accuracy of tracer gas measurements in ventilated spaces. , 2009 .