A COMPREHENSIVE STUDY ON DIFFERENT METHODS FOR AIR EXCHANGE RATES MEASUREMENT IN A NATURALLY VENTILATED DAIRY HOUSE

Samer, M.

doi:10.21608/mjae.2012.101385

A COMPREHENSIVE STUDY ON DIFFERENT METHODS FOR AIR EXCHANGE RATES MEASUREMENT IN A NATURALLY VENTILATED DAIRY HOUSE

Document Type : Original Article

Author

M. Samer

Assistant Professor, Cairo University, Faculty of Agriculture, Department of Agricultural Engineering, El-Gammaa Street, 12613 Giza, Egypt

10.21608/mjae.2012.101385

Abstract

The major problem of natural ventilation is the lack of accurate, continuous and online measuring and controlling techniques for air exchange rates (AER) which is crucial for the quantification of gaseous emissions. Therefore, this papers aims at comparing four measurement methods and to recommend thereof one method for further developments. Thirty six experiments were performed to study the AERs in a naturally ventilated dairy barn through four summer seasons and three winter seasons. The AERs were determined using moisture (H₂O) balance, heat balance (HB), CO₂-balance and tracer gas technique (TGT). The statistical analyses were correlation analysis, regression model, ANOVA model and t-test. Continuous measurements of CO₂ concentrations, temperature and relative humidity inside and outside the building were performed. The H₂O-balance showed reliable results through winter seasons and slightly acceptable results through summer seasons. The error sources of H₂O-balance are: the difference between the internal and external humidity levels which depend in turn on the accuracy of the used temperature-humidity sensors and their locations, the correctness of the used factors (e.g. the moisture produced by one cow and per mass unit), and the accuracy of the calculations of the humidity ratios. The HB showed acceptable results to some extent through summer seasons and unsatisfactory results through winter seasons. The error sources of HB are: the calculations accuracy of the net area of the different building components and the determination of the relevant overall heat transfer coefficients, the temperature difference which depends in turn on the accuracy of the used temperature-humidity sensors and their locations,

and the sensible heat produced by the animals which depends on the physiological changes of the animals. The CO₂-balance showed unexpected high differences to the other methods in some cases. The error sources of CO₂-balance are: the use of calculation models for metabolic energy, the amount of CO₂ produced per energy unit, the quantity of CO₂ produced emitted from manure, variations of ambient temperatures and the location of CO₂ measuring points. The TGT showed reliable results compared to HB, H₂O-balance and CO₂-balance. Therefore, the TGT should be further developed, where it delivers comparable results and is independent on the physiological parameters. The airflow rates (AFRs), subject to TGT, were 0.12 m³ s^-1 m^-2, 1.15 m³ s^-1 cow^-1, 0.88 m³ s^-1 LU^-1(LU is livestock unit of 500 kg), 395 m³ s^-1 and 470 kg air s^-1 through summer seasons, and 0.08 m³ s^-1 m^-2, 0.83 m³ s^-1 cow^-1, 0.64 m³ s^-1 LU^-1, 275 m³ s^-1 and 328 kg air s^-1 through winter seasons. The AERs were 37, 81, 63 and 62 h^-1 through summer seasons, and 40, 143, 61 and 39 h^-1 through winter seasons subject to H₂O-balance, HB, CO₂-balance and TGT, respectively.

Keywords

Main Subjects

Agricultural Constructions Engineering

References

Albright, L. D. 1990. Environment Control for Animals and Plants. St. Joseph, Michigan, USA: ASAE.

BfS. 1993. Radiation and radiation protection. Information brochure. Salzgitter, Germany: Federal Office for Radiation Protection.

CIGR. 2002. Climatization of animal houses. In S. Pedersen, & K. Sallvik (Eds.), Climatization of animal houses. Working Group Report on: Heat and moisture production at animal and house level. Denmark: DIAS, ISBN 87-88976-60-2.

CIGR. 1984. Climatization of animal houses. Working Group Report on: Climatization of animal houses. Scotland, UK: International Commission of Agricultural Engineering (CIGR).

Gläser, M., Klich, W., & Creifelds, A. 1986. Vergleichende Untersuchungen an ⁸⁵Kr und ¹³³Xe als Tracer, in German (Comparison between ⁸⁵Kr and ¹³³Xe as tracer). Isotopenpraxis, 22(11), 411-416.

Hatem, M. H. 1993. Theory of Structures and Agricultural Buildings, and Environmental Control (2^nd ed.). Egypt: Faculty of Agriculture, Cairo University.

Hellickson, M. A., and Walker, J. N. 1983. Ventilation of Agricultural Structures. St. Joseph, Michigan, USA: ASAE.

Liddament, M. 1996. A Guide to Energy Efficient Ventilation. IEA Energy Conservation in Buildings and Community Systems Programme, Annex V Air Infiltration and Ventilation Centre, Coventry, England.

Lindley, J. A., and Whitaker, J.H. 1996. Agricultural Buildings and Structures. St. Joseph, Michigan, USA: ASAE.

LLBB. 2005. Jahresbericht Verbraucherschutz und Gesundheitsschutz fur Mensch und Tier: Umweltschutz und nachhaltiger Ressourcenschutz, in German (Annual report on consumer and health protection for people and animals: Environmental protection and sustainable resource protection). Berlin, Germany: Berlin-Brandenburg State Laboratory.

Sallvik, K. 1999. Environment for Animals. In E. Bartali, A. Jongebreur, & D. Moffitt (Eds.), CIGR Handbook of Agricultural Engineering, Vol. 2 (pp. 31-88). St. Joseph, Michigan, USA: ASAE.

Samer, M., C. Ammon, C. Loebsin, M. Fiedler, W. Berg, P. Sanftleben, R. Brunsch. 2012. Moisture balance and tracer gas technique for ventilation rates measurement and greenhouse gases and ammonia emissions quantification in naturally ventilated buildings. Building and Environment, Vol. 50(4): 10-20.

Samer, M., W. Berg, H.-J. Müller, M. Fiedler, M. Gläser, C. Ammon, P. Sanftleben, and R. Brunsch. 2011a. Radioactive ⁸⁵Kr and CO₂-balance for ventilation rate measurements and gaseous emissions quantification through naturally ventilated barns. Transactions of the ASABE, Vol. 54(3): 1137-1148.

Samer, M., H.-J. Müller, M. Fiedler, C. Ammon, M. Gläser, W. Berg, P. Sanftleben, and R. Brunsch. 2011b. Developing the ⁸⁵Kr tracer gas technique for air exchange rate measurements in naturally ventilated animal buildings. Biosystems Engineering, Vol. 109(4): 276-287.

Samer, M., M. Fiedler, H.-J. Müller, M. Gläser, C. Ammon, W. Berg, P. Sanftleben, R. Brunsch. 2011c. Winter measurements of air exchange rates using tracer gas technique and quantification of gaseous emissions from a naturally ventilated dairy barn. Applied Engineering in Agriculture, Vol. 27(6): 1015-1025.

Samer, M., C. Loebsin, M. Fiedler, C. Ammon, W. Berg, P. Sanftleben, R. Brunsch. 2011d. Heat balance and tracer gas technique for airflow rates measurement and gaseous emissions quantification in naturally ventilated livestock buildings. Energy and Buildings, Vol. 43(12): 3718-3728.

Samer, M., C. Loebsin, K. von Bobrutzki, M. Fiedler, C. Ammon, W. Berg, P. Sanftleben, and R. Brunsch. 2011e. A computer program for monitoring and controlling ultrasonic anemometers for aerodynamic measurements in animal buildings. Computers and Electronics in Agriculture, Vol. 79(1): 1-12.

Samer, M., M. Fiedler, C. Loebsin, W. Berg, H.-J. Müller, M. Gläser, C. Ammon, P. Sanftleben, and R. Brunsch. 2011f. Tracer gas technique to estimate the ventilation rate through a naturally ventilated dairy barn. Landtechnik, Vol. 66(4): 286–288.

Samer, M., W. Berg, M. Fiedler, H.-J. Müller, M. Gläser, C. Ammon, R. Brunsch, C. Loebsin, O. Tober, P. Sanftleben. 2011g. Implementation of Radioactive ⁸⁵Kr for Ventilation Rate Measurements in Dairy Barns. Proceedings of the 2011 American Society of Agricultural and Biological Engineers (ASABE) Annual International Meeting, pp. 847-863, Paper No. 1110679, Louisville, Kentucky, USA.

Samer, M., M. Fiedler, K. von Bobrutzki, W. Berg, H.-J. Müller, M. Gläser, C. Ammon, C. Loebsin, O. Tober, P. Sanftleben, R. Brunsch. 2011h. Luftwechselmessungen im freigelüfteten Milchviehstall, in German (Measurements of air exchange rates in a naturally ventilated dairy barn). Tagung des Förderkreises Stallklima (Annual Conference on Supporting Stable Climate), 5-6.10.2011, Dummerstorf, Germany.

Samer, M., K. von Bobrutzki, W. Berg, A. Kiwan and D. Werner. 2011i. A computer program for monitoring and controlling ultrasonic anemometers for aerodynamic measurements in animal housing. Proceedings of the 5^th European Conference on Precision Livestock Farming, pp. 506-516, Czech Centre for Science and Society, Prague, Czech Republic.

Teye, F. K., and Hautala, M. 2007. Measuring ventilation rates in dairy buildings. International Journal of Ventilation, 6(3), 247-256.