David Janke

Leibniz Institute for Agricultural Engineering and Bioeconomy | ATB · Engineering for Livestock Management

In natural ventilation system-enabled dairy buildings (NVDB), achieving accurate gas emission values is highly complicated. The external weather affects measurements of the gas concentration of pollutants (c P) and volume flow rate (Q) due to the open-sided design. Previous research shows that increasing the number of sensors at the side opening is...

The quantification of gas emissions from livestock housings is a complex and challenging measurement task because performing emission measurements under practice conditions requires a high level of expertise and poses significant challenges to obtaining a careful evaluation and a reliable validation. Many measurement methods have been developed in...

The infrared photoacoustic spectroscopy is a common gas sensing technique used for research activities to perform continuous measurement of gas concentrations. Few research works have investigated how to collect data and obtain reliable measurements in open and semi-open dairy houses for gas concentration estimation. In the present study, measureme...

Accurate internal air distribution prediction facilitates the analysis of occupant thermal comfort and the control of gaseous contaminants within naturally ventilated livestock buildings (NVLB). However, the dynamic and random change in external wind conditions makes it difficult to predict the air distribution. This study compares three scenarios...

One way to estimate ammonia emission rates from naturally ventilated housing systems is to scale-up mechanistic modeling results. However, obtaining the relevant data to set initial and boundary conditions adequately is usually very challenging and for a whole barn barely possible. This study has investigated the potential of coupling different mec...

An increasing number of large pig farms are being built in multi-floor pig buildings (MFPBs) in China. Currently, the ventilation system of MFPB varies greatly and lacks common standards. This work aims to compare the ventilation performance of three popular MFPB types with different placement of fans using the Computational Fluid Dynamics (CFD) te...

Ammonia and greenhouse gases have a negative impact on the environment. The most important agricultural sources of ammonia are dairy cattle housing systems, which are mainly naturally ventilated. Estimating emissions for naturally ventilated barns (NVB) is challenging due to the large number of influencing factors. Most notably, the direct coupling...

Methane (CH4) emissions from dairy husbandry are a hot topic in the context of active climate protection, where housing systems with slatted floors and slurry storage inside are in general expected to emit more than systems with solid floors. There are multiple factors, including climate conditions, that modulate the emission pattern. In this study...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Content NIR Sensors Challenges and potential of NIR sensors to simplify the generation of nitrogen flow balances – Digital mapping of nitrogen cycles ..... 1 On Farm Validation of different NIR Sensors for Manure Sensing ..... 9 Combine Harvester Analysis of Combine Harvester Threshing Systems Across Different Climate Regions ..... 17 An interactiv...

Agriculture is a major emitter of particulate matter (PM), which causes health problems and can act as a carrier of the pathogen material that spreads diseases. The aim of this study was to investigate an open-source solver that simulates the transport and dispersion of PM for typical agricultural applications. We investigated a coupled Eulerian–La...

With an increasing number of naturally ventilated dairy barns (NVDBs), the emission of ammonia and greenhouse gases into the surrounding environment is expected to increase as well. It is very challenging to accurately determine the amount of gases released from a NVDB on-farm. Moreover, control options for the micro-climate to increase animal welf...

The tracer gas method is one of the common ways to evaluate the air exchange rate in a naturally ventilated barn. One crucial condition for the accuracy of the method is that both considered gases (pollutant and tracer) are perfectly mixed at the points where the measurements are done. In the present study, by means of computational fluids dynamics...

Ammonia emissions from naturally ventilated livestock buildings (NVLBs) pose a serious environmental problem. However, the mechanisms that control these emissions are still not fully understood. One promising method for understanding these mechanisms is physical modelling in wind tunnels. This paper reviews studies that have used this method to inv...

The determination of air exchange rates (AER) and emissions from naturally ventilated livestock systems is subject to great uncertainty. The aim of this thesis was to investigate the influence of the number and positions of gas and velocity samplings on the determination of AER and emissions as well as to optimize and further develop currently appl...

Ammonia emissions damage the environment and have negative consequences for human and animal health. In the German livestock sector, most ammonia emissions come from naturally ventilated dairy barns. To reduce emissions, Germany has signed the EU Directive 2016/2284 to achieve a stepwise decrease in the ammonia emissions ceiling. The aim of this st...

Limited available land for livestock farming and increasing land-use costs have forced some large animal feeding operations to build animal barns from conventional one-floor to multi-floor in China recently because multi-floor animal building (MFAB) has a great advantage in saving land utilization. The ventilation system is an important part of ani...

Along with industry and transportation, agriculture is one of the main sources of primary particulate matter (PM) emissions worldwide. Bioaerosol formations and PM release during livestock manure field application and the associated threats to environmental and human health are rarely investigated. In the temperate climate zone, field fertilization...

The airflow in dairy barns is affected by many factors, such as the barn’s geometry, weather conditions, configurations of the openings, cows acting as heat sources, flow obstacles, etc. Computational fluids dynamics (CFD) has the advantages of providing detailed airflow information and allowing fully-controlled boundary conditions, and therefore i...

The direct measurement of emissions from naturally ventilated dairy barns is challenging due to their large openings and the turbulent and unsteady airflow at the inlets and outlets. The aim of this study was to quantify the impacts of the number and positions of sensors on the estimation of volume flow rate and emissions. High resolution measureme...

A reliable quantification of greenhouse gas emissions is a basis for the development of adequate mitigation measures. Protocols for emission measurements and data analysis approaches to extrapolate to accurate annual emission values are a substantial prerequisite in this context. We systematically analyzed the benefit of supervised machine learning...

The air change rate (ACR) of naturally ventilated dairy buildings (NVDBs) plays an important part in the design and control of the ventilation system, as well as in the estimation of the gaseous emission rate. The objectives of this research were to model the ACR based on a quantitative investigation of the relationship between the ACR and its pote...

Airflow inside naturally ventilated dairy (NVD) buildings is highly variable and difficult to understand due to the lack of precious measuring techniques with the existing methods. Computational fluid dynamics (CFD) was applied to investigate the effect of different seasonal opening combinations of an NVD building on airflow patterns and airflow ra...

Emissions and ventilation rates (VRs) in naturally ventilated dairy barns (NVDBs) are usually measured using indirect methods, where the choice of inside and outside sampling locations (i.e. sampling strategy) is crucial. The goal of this study was to quantify the influence of the sampling strategy on the estimation of emissions and VRs. We equippe...

Two transient open source solvers, OpenFOAM and ParMooN, and the commercial solver Ansys Fluent are assessed with respect to the simulation of the turbulent air flow inside and around a dairy barn. For this purpose, data were obtained in an experimental campaign at a 1:100 scaled wind tunnel model. All solvers used different meshes, discretization...

The application of naturally ventilated pig buildings (NVPBs) with outdoor exercise yards is on the rise mainly due to animal welfare considerations, while the issue of emissions from the buildings to the surrounding environment is important. Since air pollutants are mainly transported by airflow, the knowledge on the airflow characteristics downwi...

The application of naturally ventilated pig buildings (NVPBs) with outdoor exercise yards is on the rise mainly due to animal welfare considerations, while the issue of emissions from the buildings to the surrounding environment is important. Since air pollutants are mainly transported by airflow, the knowledge on the airflow characteristics downwi...

The mandate to limit global temperature rise calls for a reliable quantification of gaseous pollutant emissions as a basis for effective mitigation. Methane emissions from ruminant fermentation are of particular relevance in the context of greenhouse gas mitigation. The emission dynamics are so far insufficiently understood. We analyzed hourly meth...

Naturally ventilated livestock buildings (NVLB) represent one of the most significant sources of ammonia emissions. However, even the dispersion of passive gas in an NVLB is still not well understood. In this paper, we present a detailed investigation of passive pollutant dispersion in a model of a cattle barn using the wind tunnel experiment metho...

The discharge coefficient (Cd) is a characteristic parameter of an opening, which represents the effect of flow contraction and frictional losses when the flow goes across the opening. It is an important parameter for the ventilation rate determination when using the orifice equation method. The objectives of this study were to investigate the rela...

Environmental protection efforts can only be effective in the long term with a reliable quantification of pollutant gas emissions as a first step to mitigation. Measurement and analysis strategies must permit the accurate extrapolation of emission values. We systematically analyzed the added value of applying modern machine learning methods in the...

In the last decades, a global warming trend was observed. Along with the temperature increase, modifications in the humidity and wind regime amplify the regional and local impacts on livestock husbandry. Direct impacts include the occurrence of climatic stress conditions. In Europe, cows are economically highly relevant and are mainly kept in natur...

The Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB) works on a range of interdisciplinary and transdisciplinary basic and applied research projects which deal with emissions, animal welfare and veterinary issues. Through activate participation in Food and Agriculture Organization (FAO) of the United Nations, The Intergovernmenta...

Air flow assessment in animal husbandry is an important issue in the context of welfare and emission. The aim of this study was to implement a porous medium approach for the numerical simulation of air flow in the animal occupied zone (AOZ) of a dairy building. Computational fluid dynamics (CFD) was used to determine the flow resistance properties,...

In the last decades, an exceptional global warming trend was observed. Along with the temperature increase, modifications in the humidity and wind regime amplify the regional and local impacts on livestock husbandry. Direct impacts include the occurrence of climatic stress conditions. In Europe, cows are economically highly relevant and are mainly...

The discharge coefficient (Cd) of an opening is an important parameter in the application of the orifice equation to calculate the airflow rate of naturally-ventilated buildings. It is questionable to regard Cd as a constant under varied external airflows for large openings that are often applied in dairy buildings. This study investigated the impa...

Gaseous emissions from livestock buildings have been a research focus for many years. In particular, quantifying emissions from naturally ventilated buildings is not trivial because it requires accurately determining the air exchange rate (AER) and representative gaseous concentration values in the exhaust and in the incoming air. Improvements are...

To provide good indoor air quality for livestock, and quantify emission of ammonia and greenhouse gases, it is essential to understand indoor air characteristics with respect to ventilation openings in naturally ventilated livestock buildings. The objectives of this study were to investigate the influence of the sidewall opening size and location o...

Well-understanding indoor air movement with respect to openings in naturally-ventilated buildings is essential to provide healthy and comfortable indoor climate for livestock. This study investigated the effects of the sidewall opening configurations on internal airflow fields and air velocity characteristics within the animal occupied zone (AOZ)....

It is important to estimate the ventilation rate of animal houses accurately for the purpose of reducing emissions and providing comfortable indoor climate. The orifice equation is widely applied for estimating the airflow rate of naturally ventilated dairy barns. However, to regard openings’ discharge coefficient (Cd) as a constant maybe not true...

The microclimatic conditions in dairy buildings affect animal welfare and gaseous emissions. Measurements are highly variable due to the inhomogeneous distribution of heat and humidity sources (related to farm management) and the turbulent inflow (associated with meteorologic boundary conditions). The selection of the measurement strategy (number a...

Discharge coefficient of the opening is one of the most important parameters in accurately estimating ventilation rate of a building when applying orifice equation, which maybe not suitable to be taken as a constant value for wind-driven cross ventilated dairy barns. This study aims to investigate the impact of wall porosity and wind speed on disch...

Integrated modelling to assess optimisation potentials for cattle housing climate - Volume 7 Issue 3 - S. Hempel, D. Janke, M. König, C. Menz, A. Englisch, S. Pinto, V. Sibony, I. Halachmi, L. Rong, C. Zong, G. Zhang, E. Sanchis, F. Estelle, S. Calvet, E. Galan, A. del Prado, C. Ammon, B. Amon, T. Amon

Emissions and climate of naturally ventilated dairy barns depend directly on external weather conditions and are highly variable in space and time. We model the complex flow patterns numerically and physically. The results of model simulations and on-farm data are mutually validated. In the framework of the FACCE-ERA-Net project OptiBarn regional s...