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Friedrich-Wilhelm-Lübke-Koog, Germany

Samer M.,Leibniz Institute for Agricultural Engineering | Samer M.,Cairo University | Ammon C.,Leibniz Institute for Agricultural Engineering | Loebsin C.,State Institute for Agriculture and Fishery MV | And 4 more authors.
Building and Environment | Year: 2012

Experiments were performed to study the ventilation rates in a naturally ventilated animal building through four summer seasons and three winter seasons. The ventilation rates were determined using moisture (H 2O) balance, tracer gas technique (TGT) and CO 2-balance. The statistical analyses were correlation analysis, regression model and t-test. Continuous measurements of gaseous concentrations (NH 3, CH 4, CO 2 and N 2O), temperature and relative humidity inside and outside the building were performed. The H 2O-balance showed reliable results through winter seasons and acceptable results to some extent through summer seasons. The CO 2-balance showed unexpected high differences to the other methods in some cases. The TGT showed reliable results compared to H 2O-balance and CO 2-balance. The air exchange rates (AERs) were 37.2, 61.6 and 63 h -1 through summer seasons, and 40.3, 38.9 and 60.5 h -1 through winter seasons subject to H 2O-balance, TGT and CO 2-balance, respectively. The emission rates through summer seasons, subject to TGT, were 191, 855, 73,877 and 45.6 g d -1 AU -1; and through winter seasons were 88, 463, 55,976 and 47.3 g d -1 AU -1, for NH 3, CH 4, CO 2 and N 2O, respectively. © 2011 Elsevier Ltd. Source


Samer M.,Leibniz Institute for Agricultural Engineering | Samer M.,Cairo University | Fiedler M.,Leibniz Institute for Agricultural Engineering | Muller H.-J.,Leibniz Institute for Agricultural Engineering | And 5 more authors.
Applied Engineering in Agriculture | Year: 2011

Measuring the ventilation rates and then quantifying the gaseous emissions from naturally ventilated barns is a particularly difficult task and associated with large uncertainties; where no accurate, reliable, and online method is available for ventilation rate measurements. Therefore, the objective of this study was to develop further the tracer gas technique (TG) for ventilation rate measurements through winter seasons. Fifteen field experiments were carried out to study the ventilation rates in a naturally ventilated dairy barn located in North Germany through three consecutive winter seasons. During each field experiment, continuous measurements of gaseous concentrations (NH3, CO 2, CH 4, and N 2O) inside and outside the barn and tracer gas experiments were carried out. Meanwhile, the microclimatic and climatic conditions were measured and recorded. The air exchange rates (AERs) and then the ventilation rates were estimated by the TG and the CO 2-balance which was set as reference method, in this study, for the purpose of statistical analysis. Three factors with two levels each were tested and they are: 85Kr point release source versus 85Kr line release source, average a-values versus sum impulses, selected radiation counters versus all radiation counters; resulting in eight factor combinations. The results were compared with each other by developing a linear regression model and carrying out Pearson correlation analysis. The differences between the reference method and the eight factor combinations were tested using the ANOVA model. The results showed that the best factor combinations were: (1) line release source considering the impulses recorded by selected radiation counters and implementing the sum method of all impulses where high R-square value of 0.82 and reliable parameter estimate of 1.00±0.19 were found for this combination, and (2) point release source considering the impulses recorded by all radiation counters and implementing the sum method of all impulses where high R-square value of 0.91 and reliable parameter estimate of 1.19±0.15 were found for this combination. The average gaseous emissions through the different winter seasons, subject to the reference method, were 2.9, 14.5, 1785, and 1.6 g h -1 AU -1 for NH 3, CH 4, CO 2, and N 2O, respectively. © 2011 American Society of Agricultural and Biological Engineers. Source


Samer M.,Leibniz Institute for Agricultural Engineering | Samer M.,Cairo University | Loebsin C.,State Institute for Agriculture and Fishery MV | Fiedler M.,Leibniz Institute for Agricultural Engineering | And 4 more authors.
Energy and Buildings | Year: 2011

Experiments were performed to study the airflow rates (AFRs) in a naturally ventilated building through four summer seasons and three winter seasons. The AFRs were determined using heat balance (HB), tracer gas technique (TGT) and CO 2-balance as averages of the values of all experiments carried out through the different seasons. The statistical analyses were correlation analysis, regression model and t-test. Continuous measurements of gaseous concentrations (NH 3, CH 4, CO 2 and N 2O) and temperatures inside and outside the building were performed. The HB showed slightly acceptable results through summer seasons and unsatisfactory results through winter seasons. The CO 2-balance showed unexpected high differences to the other methods in some cases. The TGT showed reliable results compared to HB and CO 2-balance. The AFRs, subject to TGT, were 0.12 m 3 s -1 m -2, 1.15 m 3 s -1 cow -1, 0.88 m 3 s -1 LU -1, 56 h -1, 395 m 3 s -1 and 470 kg s -1 through summer seasons, and 0.08 m 3 s -1 m -2, 0.83 m 3 s -1 cow -1, 0.64 m 3 s -1 LU -1 39 h -1, 275 m 3 s -1 and 328 kg s -1 through winter seasons. The AFRs are not independent values, rather they were estimated for specific reference values, which are: area, cow and LU as well as rates. The emission rates through summer seasons, subject to TGT, were 9.4, 40, 3538 and 2.3 g h -1 cow -1; and through winter seasons were 4.8, 19, 2332 and 2.6 g h -1 cow -1, for NH 3, CH 4, CO 2 and N 2O, respectively. © 2011 Elsevier B.V. Source


Saha C.K.,Leibniz Institute for Agricultural Engineering | Saha C.K.,Bangladesh Agricultural University | Ammon C.,Leibniz Institute for Agricultural Engineering | Berg W.,Leibniz Institute for Agricultural Engineering | And 4 more authors.
Biosystems Engineering | Year: 2013

Natural ventilation (NV) of buildings refers to the exchange of indoor air with outdoor air due to pressure differences caused by wind and/or buoyancy. Increased knowledge of the factors that affect NV and emissions from naturally ventilated dairy (NVD) buildings may lead to a better understanding of indoor air quality, an improvement of emission abatement technologies and a refinement of emission models. The influence of external wind speed and direction on point concentration, air change rate, ammonia (NH3) and methane (CH4) emissions was evaluated in an NVD building located in northern Germany. The measured data were classified according to four wind direction groups: 0°-10° (N), 85°-95° (E), 175°-185° (S), and 265°-275° (W), with consideration for similar wind frequencies and representation of each major side for further analyses and comparisons. The results showed that wind speed and wind direction had significant influence on air change per hour (ACH) (P < 0.05) both individually and when interacting. In contrast, only wind speed and interactions of external wind speed and direction significantly affected NH3 and CH4 emissions (P < 0.05). The surrounding obstacles, other climate parameters (temperature and relative humidity) and other emission sources should be taken into account when interpreting the effects of wind direction on ACH and emissions. Empirical models for ACH, NH3 and CH4 emissions were developed. Intensive experiments in the lab (e.g. scale model in boundary layer wind tunnel) and long-term measurement including all seasons at full scale are required to establish a good empirical model. © 2012 IAgrE. Source


Samer M.,Leibniz Institute for Agricultural Engineering | Samer M.,Cairo University | Loebsin C.,State Institute for Agriculture and Fishery MV | von Bobrutzki K.,Leibniz Institute for Agricultural Engineering | And 5 more authors.
Computers and Electronics in Agriculture | Year: 2011

Ultrasonic anemometers (USAs) are widely implemented in animal housing to measure the air velocity in different measuring points throughout the whole barn, which ultimately leads to determine the velocity fields and the air flow patterns drawing a clear vision of aerodynamics inside animal buildings. The problem is the timely inconsistent data transmission from the different USAs leading to varied data recording, which makes the comparison between the recorded velocities in different points timely inappropriate. One key issue is to monitor and control the USAs, meanwhile, debug and record the data. Therefore, LabVIEW 8.5, which is a platform and development environment for a visual programming language, was used to configure a computer program to monitor and control the USAs. The principal functions of the system are represented in a main block diagram which consists of 39 sub-diagrams. Five versions of the program were consecutively developed, and then each version was validated and further developed to get the next enhanced version, and so on till Version 5.0. The evaluation and data recording are carried out simultaneously, where the data are transferred from the USAs to the program which detects accidental errors that may have been introduced during data transmission or storage using a checksum algorithm. The developed computer program has been implemented successfully for monitoring and controlling USAs used for carrying out air velocity measurements in livestock housing. Three measurements campaigns were performed to investigate the air profile inside a dairy barn under two conditions, which are "ceiling fans on" and "ceiling fans off", where the average air velocities were 0.98 and 0.59ms -1, respectively. © 2011 Elsevier B.V. Source

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