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Peter Demeyer – One of the best experts on this subject based on the ideXlab platform.

  • Effect of sampling density on the reliability of Airflow Rate measurements in a naturally ventilated animal mock-up building
    Energy and Buildings, 2017
    Co-Authors: Gerlinde De Vogeleer, Jan Pieters, Philippe Van Overbeke, Peter Demeyer
    Abstract:

    Abstract Measuring natural ventilation Rates in buildings with large vents with high accuracy and precision is not straight forward due to high spatial and temporal variabilities in the velocity distribution. Simplification of Airflow Rate measurements are mostly effectuated by lowering sampling density. Different sampling densities were investigated for both direct and tracer gas methods and compared with a detailed direct measurement method were in a naturally ventilated animal mock-up building. The results obtained by the reference method indicated that using only sampling locations in the middle of the side openings overestimated the Airflow Rate. In view of wind variations, better accuracy, precision and lower coefficients of variation were obtained with a higher number of sampling locations. The coefficients of variation varied between 5% for the reference and 29% using only one sampling location in the side outlet. In the ridge opening, only one middle sampling location was sufficient for an accuracy of 2% and a precision of 3%. The indirect tracer gas method gave varying concentrations with high confidence intervals resulting in non-significantly different measurement results between the different sampling stRategies. The pattern of sampling locations was found to be very important resulting in different accuracies for a given sampling density.

  • Methodology for Airflow Rate measurements in a naturally ventilated mock-up animal building with side and ridge vents
    Building and Environment, 2016
    Co-Authors: P. Van Overbeke, Peter Demeyer, G. De Vogeleer, Eva Brusselman, Luciano Barreto Mendes, J.g. Pieters
    Abstract:

    Currently there exists no generally accepted reference technique to measure the ventilation Rate through naturally ventilated (NV) vents. This has an impact on the reliability of Airflow Rate control techniques and emission Rate measurements in NV animal houses. As an attempt to address this issue a NV test facility was built to develop new Airflow Rate measurement techniques for both side wall and ridge vents. Three set-ups were used that differed in vent configuration, i.e. one cross ventilated set-up and two ridge ventilated set-ups with different vent sizes. The Airflow through the side vents was measured with a technique based on an automatic traverse movement of a 3D ultrasonic anemometer. In the ridge, 7 static 2D ultrasonic anemometers were installed. The methods were validated by applying the air mass conservation principle, i.e. the inflow Rates must equal the outflow Rates. The calculated in – and outflow Rates agreed within (5 +/- 8)%, (8 +/- 5)% and (-9 +/- 7)% for the three different set-ups respectively, over a large range of wind incidence angles. It was found that the side vent configuration was of large importance for the distribution of the Airflow Rates through the vents. The ridge proved to be a constant outlet, whilst side vents could change from outlet to inlet depending on the wind incidence angle. The range of wind incidence angles in which this transition occurred could be clearly visualized.

  • Assessing Airflow Rates of a naturally ventilated test facility using a fast and simple algorithm supported by local air velocity measurements
    Building and Environment, 2016
    Co-Authors: G. De Vogeleer, P. Van Overbeke, Eva Brusselman, Jan Pieters, Luciano Barreto Mendes, Peter Demeyer
    Abstract:

    Abstract The high spatial and temporal variations of Airflow patterns in ventilation openings of naturally ventilated animal houses make it difficult to accuRately measure the Airflow Rate. This paper focusses on the development of a fast assessment technique for the Airflow Rate of a naturally ventilated test facility through the combination of a linear algorithm and local air velocity measurements. This assessment technique was validated against detailed measurement results obtained by the measuring method of Van Overbeke et al. (2015) as a reference. The total air velocity | U ¯ | , the normal | Y ¯ | and tangential velocity component | X ¯ | and the velocity vector U ¯ measured at the meteomast were chosen as input variables for the linear algorithms. The Airflow Rates were split in a group where only uni-directional flows occurred at vent level (no opposite directions of | Y ¯ | present in the Airflow pattern of the opening), and a group where bi-directional flows occurred (the air goes simultaneously in and out of the opening). For Airflow Rates with uni-directional flows the input variables U ¯ and | Y ¯ | yielded the most accuRate results. For this reason, it was suggested to use the | Y ¯ | instead of | U ¯ | in ASHRAE’s formula of Q = E × A × | U ¯ | . For bi-directional flows a multiple linear model was suggested where input variable U ¯ gave the best results to assess the Airflow Rate.

M. Ben Amor – One of the best experts on this subject based on the ideXlab platform.

P. Van Overbeke – One of the best experts on this subject based on the ideXlab platform.

  • Methodology for Airflow Rate measurements in a naturally ventilated mock-up animal building with side and ridge vents
    Building and Environment, 2016
    Co-Authors: P. Van Overbeke, Peter Demeyer, G. De Vogeleer, Eva Brusselman, Luciano Barreto Mendes, J.g. Pieters
    Abstract:

    Currently there exists no generally accepted reference technique to measure the ventilation Rate through naturally ventilated (NV) vents. This has an impact on the reliability of Airflow Rate control techniques and emission Rate measurements in NV animal houses. As an attempt to address this issue a NV test facility was built to develop new Airflow Rate measurement techniques for both side wall and ridge vents. Three set-ups were used that differed in vent configuration, i.e. one cross ventilated set-up and two ridge ventilated set-ups with different vent sizes. The Airflow through the side vents was measured with a technique based on an automatic traverse movement of a 3D ultrasonic anemometer. In the ridge, 7 static 2D ultrasonic anemometers were installed. The methods were validated by applying the air mass conservation principle, i.e. the inflow Rates must equal the outflow Rates. The calculated in – and outflow Rates agreed within (5 +/- 8)%, (8 +/- 5)% and (-9 +/- 7)% for the three different set-ups respectively, over a large range of wind incidence angles. It was found that the side vent configuration was of large importance for the distribution of the Airflow Rates through the vents. The ridge proved to be a constant outlet, whilst side vents could change from outlet to inlet depending on the wind incidence angle. The range of wind incidence angles in which this transition occurred could be clearly visualized.

  • Assessing Airflow Rates of a naturally ventilated test facility using a fast and simple algorithm supported by local air velocity measurements
    Building and Environment, 2016
    Co-Authors: G. De Vogeleer, P. Van Overbeke, Eva Brusselman, Jan Pieters, Luciano Barreto Mendes, Peter Demeyer
    Abstract:

    Abstract The high spatial and temporal variations of Airflow patterns in ventilation openings of naturally ventilated animal houses make it difficult to accuRately measure the Airflow Rate. This paper focusses on the development of a fast assessment technique for the Airflow Rate of a naturally ventilated test facility through the combination of a linear algorithm and local air velocity measurements. This assessment technique was validated against detailed measurement results obtained by the measuring method of Van Overbeke et al. (2015) as a reference. The total air velocity | U ¯ | , the normal | Y ¯ | and tangential velocity component | X ¯ | and the velocity vector U ¯ measured at the meteomast were chosen as input variables for the linear algorithms. The Airflow Rates were split in a group where only uni-directional flows occurred at vent level (no opposite directions of | Y ¯ | present in the Airflow pattern of the opening), and a group where bi-directional flows occurred (the air goes simultaneously in and out of the opening). For Airflow Rates with uni-directional flows the input variables U ¯ and | Y ¯ | yielded the most accuRate results. For this reason, it was suggested to use the | Y ¯ | instead of | U ¯ | in ASHRAE’s formula of Q = E × A × | U ¯ | . For bi-directional flows a multiple linear model was suggested where input variable U ¯ gave the best results to assess the Airflow Rate.

  • Development of a reference method for Airflow Rate measurements through rectangular vents towards application in naturally ventilated animal houses
    Computers and Electronics in Agriculture, 2015
    Co-Authors: P. Van Overbeke, G. De Vogeleer, Eva Brusselman, Jan Pieters, Peter Demeyer
    Abstract:

    A naturally ventilated test facility was built.An Airflow Rate measuring method using 3D ultrasonic anemometers was developed.The method was successfully validated through the law of mass conservation.The effect of the wind incidence angle and speed on the Airflow Rate was studied.The necessity of measuring the 3D in-/outflow pattern was proven. In order to measure the Airflow Rate and emission Rate of a naturally ventilated livestock building correctly, more reliable measuring techniques need to be developed. A test facility with a cross ventilated room was built at the Institute for Agricultural and Fisheries Research (Belgium) to study a new Airflow Rate measuring method. This method is based on an automated traverse movement of a 3D ultrasonic anemometer across 2 vents of 0.5mi?1.0m. To cope with the fluctuating wind velocity profile, a velocity measurement of 10s in 16 equally distributed measuring points is needed. Moreover, 10 traverse replicates are needed to obtain a representative average flow Rate. Based on the law of mass conservation, the accuracy of the method was determined by calculating the relative deviation between the simultaneously measured Airflow Rates through both vents. A relative error of -1?11% was found, averaged over all wind incidence angles. However, wind angles parallel to the vent resulted in larger relative errors. A 3D velocity measurement in the in- or outlet opening of the test facility is necessary to obtain a correct flow Rate. This was especially true in the outlet where up to 30% of the Airflow Rate was delivered by velocity components other than normal to the vent. The test facility and the developed ventilation Rate measuring method can serve as a reference to study and validate new and existing ventilation Rate measuring methods.

G. De Vogeleer – One of the best experts on this subject based on the ideXlab platform.

  • Methodology for Airflow Rate measurements in a naturally ventilated mock-up animal building with side and ridge vents
    Building and Environment, 2016
    Co-Authors: P. Van Overbeke, Peter Demeyer, G. De Vogeleer, Eva Brusselman, Luciano Barreto Mendes, J.g. Pieters
    Abstract:

    Currently there exists no generally accepted reference technique to measure the ventilation Rate through naturally ventilated (NV) vents. This has an impact on the reliability of Airflow Rate control techniques and emission Rate measurements in NV animal houses. As an attempt to address this issue a NV test facility was built to develop new Airflow Rate measurement techniques for both side wall and ridge vents. Three set-ups were used that differed in vent configuration, i.e. one cross ventilated set-up and two ridge ventilated set-ups with different vent sizes. The Airflow through the side vents was measured with a technique based on an automatic traverse movement of a 3D ultrasonic anemometer. In the ridge, 7 static 2D ultrasonic anemometers were installed. The methods were validated by applying the air mass conservation principle, i.e. the inflow Rates must equal the outflow Rates. The calculated in – and outflow Rates agreed within (5 +/- 8)%, (8 +/- 5)% and (-9 +/- 7)% for the three different set-ups respectively, over a large range of wind incidence angles. It was found that the side vent configuration was of large importance for the distribution of the Airflow Rates through the vents. The ridge proved to be a constant outlet, whilst side vents could change from outlet to inlet depending on the wind incidence angle. The range of wind incidence angles in which this transition occurred could be clearly visualized.

  • Assessing Airflow Rates of a naturally ventilated test facility using a fast and simple algorithm supported by local air velocity measurements
    Building and Environment, 2016
    Co-Authors: G. De Vogeleer, P. Van Overbeke, Eva Brusselman, Jan Pieters, Luciano Barreto Mendes, Peter Demeyer
    Abstract:

    Abstract The high spatial and temporal variations of Airflow patterns in ventilation openings of naturally ventilated animal houses make it difficult to accuRately measure the Airflow Rate. This paper focusses on the development of a fast assessment technique for the Airflow Rate of a naturally ventilated test facility through the combination of a linear algorithm and local air velocity measurements. This assessment technique was validated against detailed measurement results obtained by the measuring method of Van Overbeke et al. (2015) as a reference. The total air velocity | U ¯ | , the normal | Y ¯ | and tangential velocity component | X ¯ | and the velocity vector U ¯ measured at the meteomast were chosen as input variables for the linear algorithms. The Airflow Rates were split in a group where only uni-directional flows occurred at vent level (no opposite directions of | Y ¯ | present in the Airflow pattern of the opening), and a group where bi-directional flows occurred (the air goes simultaneously in and out of the opening). For Airflow Rates with uni-directional flows the input variables U ¯ and | Y ¯ | yielded the most accuRate results. For this reason, it was suggested to use the | Y ¯ | instead of | U ¯ | in ASHRAE’s formula of Q = E × A × | U ¯ | . For bi-directional flows a multiple linear model was suggested where input variable U ¯ gave the best results to assess the Airflow Rate.

  • Development of a reference method for Airflow Rate measurements through rectangular vents towards application in naturally ventilated animal houses
    Computers and Electronics in Agriculture, 2015
    Co-Authors: P. Van Overbeke, G. De Vogeleer, Eva Brusselman, Jan Pieters, Peter Demeyer
    Abstract:

    A naturally ventilated test facility was built.An Airflow Rate measuring method using 3D ultrasonic anemometers was developed.The method was successfully validated through the law of mass conservation.The effect of the wind incidence angle and speed on the Airflow Rate was studied.The necessity of measuring the 3D in-/outflow pattern was proven. In order to measure the Airflow Rate and emission Rate of a naturally ventilated livestock building correctly, more reliable measuring techniques need to be developed. A test facility with a cross ventilated room was built at the Institute for Agricultural and Fisheries Research (Belgium) to study a new Airflow Rate measuring method. This method is based on an automated traverse movement of a 3D ultrasonic anemometer across 2 vents of 0.5mi?1.0m. To cope with the fluctuating wind velocity profile, a velocity measurement of 10s in 16 equally distributed measuring points is needed. Moreover, 10 traverse replicates are needed to obtain a representative average flow Rate. Based on the law of mass conservation, the accuracy of the method was determined by calculating the relative deviation between the simultaneously measured Airflow Rates through both vents. A relative error of -1?11% was found, averaged over all wind incidence angles. However, wind angles parallel to the vent resulted in larger relative errors. A 3D velocity measurement in the in- or outlet opening of the test facility is necessary to obtain a correct flow Rate. This was especially true in the outlet where up to 30% of the Airflow Rate was delivered by velocity components other than normal to the vent. The test facility and the developed ventilation Rate measuring method can serve as a reference to study and validate new and existing ventilation Rate measuring methods.

Manuel Mota – One of the best experts on this subject based on the ideXlab platform.