Data/hora: 02/06/2024 03:50:37

Provedor de dados: | Agricultural Engineering International : The CIGR e-journal
País: | China
Título: | Tracer gas technique, air velocity measurement and natural ventilation method for estimating ventilation rates through naturally ventilated barns
Autores: | Alaa Kiwan Kiwan; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Werner Berg; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Reiner Brunsch; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Sezin Özcan; K.U. Leuven, Faculty of Bioscience Engineering, Leuven, Belgium.; Hans-Joachim Müller; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Manfred Gläser; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Merike Fiedler; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Christian Ammon; Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.; Daniel Berckmans; K.U. Leuven, Faculty of Bioscience Engineering, Leuven, Belgium.
Data: | 2012-12-24
Ano: | 2012
Palavras-chave: | Natural ventilation; Tracer gas technique; Radioactive isotope 85Kr; Air velocity; Air exchange rate; Dairy barn.
Resumo: | Naturally ventilated barns have the advantage of providing an energy-efficient and low-noise micro-environment for animals. &amp;nbsp;Such barns are very common, especially for cattle, which are a major source of ammonia and methane emissions as well as other airborne pollutants. Emission fluxes are calculated as the product of the ventilation rate (VR) and the gas concentration. &amp;nbsp;The VR of naturally ventilated barns are directly influenced by atmospheric conditions. &amp;nbsp;Therefore, the estimation of VR involves high uncertainties; furthermore, there is no reference method for VR estimation. &amp;nbsp;For these reasons, three different methods were investigated to estimate VR through naturally ventilated dairy barns: (1) the tracer gas technique, using radioactive isotope Krypton-85 (85Kr), (2) the measurement of the air velocity through the barn openings, and (3) the natural ventilation method. &amp;nbsp;The investigations were performed in two naturally ventilated dairy barns (each with a volume of 5,670&amp;nbsp;m3) during mild (T&amp;ge;17℃) and cold weather (T&amp;lt;17℃) conditions. &amp;nbsp;The VR ranged between 48,000 and 475,000 m3/h. &amp;nbsp;There was a significant (p&amp;lt;0.01) correlation between all three methods for barn&amp;nbsp;A (Pearson&amp;rsquo;s correlation coefficient 0.59-0.86). &amp;nbsp;For barn&amp;nbsp;B only, the tracer gas and the natural ventilation method showed a significant (p=0.03) correlation (Pearson&amp;rsquo;s correlation coefficient 0.62). &amp;nbsp;The season (mild or cold) and the VR estimation method both had a significant (p&amp;lt;0.03) effect on the estimated VR for both barns. &amp;nbsp;The outside wind speed had a significant (p&amp;lt;0.005) effect on the estimated VR for barn&amp;nbsp;A. &amp;nbsp;For barn&amp;nbsp;B, this effect was not significant (p=0.052). &amp;nbsp;The tracer gas technique used has the advantage of measuring the tracer with high resolution in time (1&amp;nbsp;Hz) and space (18&amp;nbsp;or more measured points).Keywords: Natural ventilation, tracer gas technique, radioactive isotope 85Kr, air velocity, air exchange rate, dairy barn&amp;nbsp;&amp;nbsp;&amp;nbsp;
Idioma: | Inglês
Identificador: | http://www.cigrjournal.org/index.php/Ejounral/article/view/1981
Editor: | International Commission of Agricultural and Biosystems Engineering

Relação:

http://www.cigrjournal.org/index.php/Ejounral/article/download/1981/0

http://www.cigrjournal.org/index.php/Ejounral/article/download/1981/4723

http://www.cigrjournal.org/index.php/Ejounral/article/download/1981/6187

http://www.cigrjournal.org/index.php/Ejounral/article/download/1981/6188

Formato: | application/pdf
Fonte: | Agricultural Engineering International: CIGR Journal; Vol 14, No 4 (2012): CIGR Journal; 22-36
Fonte: | &lt;html /&gt;