Tracer gas technique, air velocity measurement and natural ventilation method for estimating ventilation rates through naturally ventilated barns

Authors

  • 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.

Keywords:

Natural ventilation, tracer gas technique, radioactive isotope 85Kr, air velocity, air exchange rate, dairy barn

Abstract

Naturally ventilated barns have the advantage of providing an energy-efficient and low-noise micro-environment for animals.  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.  The VR of naturally ventilated barns are directly influenced by atmospheric conditions.  Therefore, the estimation of VR involves high uncertainties; furthermore, there is no reference method for VR estimation.  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.  The investigations were performed in two naturally ventilated dairy barns (each with a volume of 5,670 m3) during mild (T≥17℃) and cold weather (T<17℃) conditions.  The VR ranged between 48,000 and 475,000 m3/h.  There was a significant (p<0.01) correlation between all three methods for barn A (Pearson’s correlation coefficient 0.59-0.86).  For barn B only, the tracer gas and the natural ventilation method showed a significant (p=0.03) correlation (Pearson’s correlation coefficient 0.62).  The season (mild or cold) and the VR estimation method both had a significant (p<0.03) effect on the estimated VR for both barns.  The outside wind speed had a significant (p<0.005) effect on the estimated VR for barn A.  For barn B, this effect was not significant (p=0.052).  The tracer gas technique used has the advantage of measuring the tracer with high resolution in time (1 Hz) and space (18 or more measured points).

Keywords: Natural ventilation, tracer gas technique, radioactive isotope 85Kr, air velocity, air exchange rate, dairy barn

 

 

 

Author Biographies

Alaa Kiwan Kiwan, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

PhD Student at Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Department of Engineering for Livestock Management, Potsdam, Germany, and Lecturer Assistant, Department of  Rural Engineering, Faculty of Agricultural Engineering, Aleppo University, Aleppo, Syria, E-mail: akiwan@atb-potsdam.de; kiwanala@cms.hu-berlin.de

Werner Berg, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Head of the Department of Engineering for Livestock Management, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Potsdam, Germany.

Reiner Brunsch, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Scientific Director of Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Sezin Özcan, K.U. Leuven, Faculty of Bioscience Engineering, Leuven, Belgium.

K.U. Leuven, Faculty of Bioscience Engineering, Division of Measure, Model & Manage Bioresponses (M3-BIORES),

Kasteelpark Arenberg 30. box 2456. 3001 Leuven, Belgium

fax +32 16 321480

Hans-Joachim Müller, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Research Scientist (Retired) at Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB),  Potsdam, Germany

Manfred Gläser, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Research Scientist and Nuclear Physicist  (Retired) at Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB),  Potsdam, Germany

Merike Fiedler, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Research Scientist at Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB),  Potsdam, Germany

Christian Ammon, Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Germany.

Technician at Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB),  Potsdam, Germany

Daniel Berckmans, K.U. Leuven, Faculty of Bioscience Engineering, Leuven, Belgium.

Director of Division of Measure, Model & Manage Bioresponses (M3-BIORES), Faculty of Bioscience Engineering, K.U. Leuven

Kasteelpark Arenberg 30. box 2456. 3001 Leuven, Belgium

tel. +32 16 321726 or +32 16 321436

fax +32 16 321480

Downloads

Published

2012-09-23

Issue

Section

II-Farm Buildings and Construction