Bjarne Bjerg

• Professor (Associate) at University of Copenhagen

This chapter gathers information about the current legal requirements related to the emission of ammonia from animal housing in 24 out of the 27 EU countries and in 7 non-EU countries. Overall, the chapter shows that most of the included countries have established substantial procedures to limit ammonia emission and practically no procedures to lim...

Increased metabolic heat production caused by breeding for higher productivity puts sows at a high risk of suffering from heat stress. To reasonably predict the actual thermal status of sows becomes essential for efficiently mitigating heat stress. However, the existing thermal indices for pigs neither have been verified by experimental data of sow...

High indoor temperatures in traditional finisher pig buildings may lead to deteriorating production results, increased pen fouling and increased respiration rate and rectal temperature. Floor cooling may improve the thermal conditions for pigs on solid floors during warm periods, and therefore the objective was to investigate whether floor cooling...

Global warming combined with increased production (i.e. more piglets, more milk and consequently more heat) means that sows are more often challenged by heat stress. The objective was to develop an effective temperature (ET) equation to predict how air temperature, velocity and humidity affect the respiration rate (RR), rectal temperature (RT) and...

Due to the climate change and the increasing heat production of modern pigs (e.g. larger size sows having a larger number of piglets nowadays), pigs are more frequently suffering heat stress. In order to prevent the occurrence of heat stress, there is a need to develop a model which can effectively and efficiently predict the effect of ambient ther...

The performance of the mechanistic two-node thermophysiological model was assessed using the experimental data with respect to gestating sows and fattening pigs. The relation between the convective heat transfer coefficient and local airspeed was derived from CFD simulation. The improvement brought by the newly proposed active module over the selec...

There is a comprehensive body of literature on how increased air temperature affects the physiology, production and behaviour of sows, while very few studies consider the thermal effects of air humidity and air velocity. This review summarises studies that have investigated effects of air temperature by reviewing published literature in which sows...

This review gathers information about the current legal requirements related to the emission of ammonia and greenhouse gases from animal housing in 21 out of the 28 EU countries and in 5 non-EU countries. Overall the review shows that most of the included countries have established substantial procedures to limit ammonia emission and practically no...

This paper reviews methods to mitigate heat stress among high productive sows. The investigated methods comprise increased ventilation, increased air velocity, snout cooling, air cooling, floor cooling, radiative cooling, drip cooling, sprinkling of water onto the sows and increased insulation. The review shows that it is very different how well th...

Two-dimensional CFD modelling was used to gain knowledge on how the presence of laying pigs affects the heat transfer in heated or cooled concrete solid floor laying areas. The study included three different floor types; A) an insulated concrete ground floor, B) an uninsulated concrete floor element with no insulation underneath, and C) a concrete...

Existing knowledge on the relative significance of air temperature, humidity, and velocity in a hot environment for housed pigs and poultry is reviewed and synthesized in an effective temperature (ET) equation. The suggested unit has an easily perceivable scale where ET is equal to air temperature if the relative humidity is 50% and the air velocit...

Optimal thermal conditions for farm animals are crucial preconditions for development of improved climate control methods. Both low and high temperatures are known to comprise both daily gain and feed efficiency. The aim of this work was to utilized published studies to determine how the ambient temperature affects the daily gain and the feed effic...

Thermal stress imposed on cows adversely affects health and productivity. Various thermal indices exist in the literature that can be used to assess the level of heat stress on cattle by linking environmental conditions with physiological responses. However, many of these indices either do not incorporate all of the environmental variables or may c...

Using solid floor instead of drained or slatted floor in the lying areas of pig pens has distinct advantages in relation to animal welfare, odour abatement and ammonia emission, energy consumption and reduced building costs. However, pig producers often opt out of providing a solid floor due to the risk of manure fouling in the lying area during wa...

A desire to reduce energy consumption associated with mechanical ventilation in conventional pig housing has led to the development of a new hybrid ventilated building design, where large adjustable openings for natural ventilation are combined with a mechanical ventilation system for under floor removal and subsequent cleaning of a limited amount...

Negative pressure ventilation with diffuse air inlet through a layer of mineral wool in the ceiling is the dominant ventilations method in Danish pig production. The method constitutes a simple way to generate appropriate thermal conditions among the animals, especially in periods with relatively low outdoor temperatures. To improve the chilling of...

The purpose of this report was to assess • how much heat it would be appropriate to remove by the floor cooling system, • which cooling source that will be most the cost effective strategy for cooling water led into the floor pipe system. The analysis assumed utilisation of the existing solid floor element (from Agrifarm) including the embedded h...

The aim of this work is to describe the previous experiences with floor cooling in pig facilities, with focus on physical, physiological and behavioural parameters of the exposed surroundings and pigs.

The aim of this report is to determine the dimensions of pipes for a potential EAHE system and to calculatethe related cost of implementation. A newly constructed finisher pig facility in Denmark is used in determination of the design requirements for the system.

Studies on the mechanisms of natural ventilation in livestock buildings are reviewed and influences on discharge and pressure coefficients are discussed. Compared to studies conducted on buildings for human occupation and industrial buildings which focus on thermal comfort, ventilation systems, indoor air quality, building physics and energy etc.,...

Ved miljøgodkendelse af husdyrbrug vil det typisk være nødvendigt at anvende ammoniak- og/eller lugtreducerende teknologi for at overholde de emissionsgrænseværdier for ammoniak og lugt, der er definerede i lov om miljøgodkendelse. Af Miljøstyrelsens Teknologiliste fremgår teknologier, som Miljøstyrelsen har anerkendt med en given reduktionseffekt...

One of the major objectives of precision livestock farming (PLF) is to provide an optimal thermal climate control in the animal occupant zones for promoting animal production and wellbeing. To achieve this goal, smart climate models that reflect the needs of different animal species and ages or feasible sensor techniques that can measure animal fel...

Danish farmers that wish to establish or expand animal production facilities have to document that the expected odour nuisances at the neighbours are kept below certain thresholds. To do so the expected odour emission must be calculated from norm figures for expected odour emission from the wished production, and a certain atmospheric dispersion mo...

Increased air velocity is a frequently used method to reduce heat stress of farm animals housed in warm conditions. The main reason why the method works is that higher air velocity increases the convective heat release from the animals. Convective heat release from the animals is strongly related to the temperature difference between the surfaces o...

Use of solid floor as an alternative to drained or slatted floor in the laying area of pig pens includes significant advantages in relation to animal welfare, low odour and ammonia emission, low energy consumption and reduced building costs, however solid floor is most often deselected by the pig producers due to the risk that fouling in the laying...

Computational Fluid Dynamics (CFD) is increasingly used to study airflow around and in livestock buildings, to develop technologies to mitigate emissions and to predict the contaminant dispersion from livestock buildings. In this paper, an example of air flow distribution in a room with two full scale pig barns was simulated to show the procedures...

En komposteringsstald er både dyrere at bygge og bruge end en sengebåsestald med sand. Den må forventes at koste ca. 3.000 kr. mere pr ko, primaert pga. større udgifter til strøelse. Denne meromkostning kan udlignes af en ydelsesstigning på ca. 3 kg maelk pr ko pr dag, eller ved en tilsvarende forbedring via en kombination af øget ydelse, laengere...

Du er her: LandbrugsInfo > Byggeri > Stalde > Kvaegstalde > Lav ammoniakemission pr. kvadratmeter i komposteringsstald Lav ammoniakemission pr. kvadratmeter i komposteringsstald Ammoniakemissionen fra komposteringsstalden er lav målt pr. m2. Trods det store areal pr. ko i komposteringsstalden, ligger ammoniakemissionen samlet set indenfor variation...

Besides welfare advantages of the compost bedded pack system (CBP) there could be a negative effect of the organic bedding on udder health. Our objectives were to evaluate the effects of a CBP on udder health compared to a free stall system (FS) with sand bedded cubicles. Within the same Danish organic farm, 330 multiparous cows were randomly alloc...

Commercial chemical or biological air cleaning systems are capable to remove more than 90 % of the ammonia in exhaust air from mechanical ventilated pig housing, but it is costly to install cleaning systems large enough to treat the large amount of air needed in warm periods. Introduction of partly pit ventilations systems where the first 10 % of v...

The paper reports experiences from the first composted bedded pack (CBP) barn for 330 dairy cows in Denmark. The design of the barn differs from corresponding barns in the US by including an under floor aeration system to enhance water evaporation from the CBP. As bedding material were mainly used garden residuals, chopped roots and heathland veget...

Ammonia, dust and odour emission from livestock production system caused negative impact to atmosphere environment and local society. It is therefore important to find a costeffective method to reduce these emissions effectively. Application of air cleaning methods including chemical and biological filter techniques has been proposed to be used to...

This review shows the theoretical background for development of lumped ventilation models that can be integrated into models that aim to aid either design or operation of low emission naturally-ventilated buildings. The strength of lumped parameter modelling methods is that they have the potential to include effects of varying outdoor climate condi...

The present article describes the current research focus and the future research trends associated with investigating emissions from naturally ventilated buildings as identified at the technical session entitled "Emission from naturally ventilated buildings (Measurement, modelling, reduction and assessment)", that was held during the International...

Gaseous emissions from livestock buildings are a major environmental concern worldwide and an increasing number of countries have now introduced legislation that aims to reduce the emission of pollutants like ammonia. This paper is the first of a series of three reviews focussing on the utilisation of different modelling techniques to estimate ammo...

The purpose of this review paper is to identify current capabilities of Computational Fluid Dynamics (CFD) modelling techniques and areas where further scientific research is required, in order to identify how best CFD can be utilised in the future as a comprehensive modelling tool that enables naturally ventilated (NV) livestock buildings to be de...

This work utilized CFD methods to investigate how different ventilation system layouts influence the ability of a partial pit exhaust ventilations system to capture ammonia emission in a growing pig unit with partly slatted and partly drained floor. The simulations showed that cleaning 10% of ventilations capacity expelled through the ceiling exhau...

The performance of five widely used turbulence models, the standard k–ε model (SKE), the renormalization group k–ε model (RNG), the realizable k–ε model (RKE), the standard k–ω model (SKW) and the shear stress transport k–ω model (KWSST), were evaluated for simulations of airflow velocities and ammonia concentrations in a 1:12.5 scale model swine b...

CFD methods were used to generate knowledge for optimization of adjustment of ventilations openings and location and adjustments of heat sources in order to minimise temperature differences in the animal occupied zone of a 58 m wide hybrid ventilated pig building. INTRODUCTION This work is part of the development of a new low emission and low energ...

It is a challenge to estimate the ventilation rate of a natural ventilated livestock building in varied wind conditions. Both experiment and numerical simulation approaches can be applied. In this paper, numerical simulations using computational fluid dynamics (CFD) and experiments using the pressure method and tracer gas method are compared. The s...

Cultivated compost housing systems for dairy cattle are reported in the literature from Israel the USA and the Netherlands. A deep-bedded pack is commonly supported by large amounts of wood shavings and sawdust to enhance microbial activity and evaporation. Aerobic composting processes are maintained by cultivating the bedded pack once or twice dai...

CFD simulations were carried out to assess the feasibility of using RANS (Reynolds – averaged Navier–Stokes) turbulence models to evaluate the performance of a partial pit ventilation system to reduce gas emission under slatted floor. The entire system included a pit model with slatted floor and pit exhaust system, a wind table to simulate ground a...

Determination of emission of contaminant gases as ammonia, methane, or laughing gas from natural ventilated livestock buildings with large opening is a challenge due to the large variations in gas concentration and air velocity in the openings. The close relation between calculated animal heat production and the carbon dioxide production from the a...

The objective of this study was to investigate the effect of different geometric sizes of wind tunnels on aerial boundary layers above the emission surface and therefore their effect on ammonia emission using CFD tool. Five wind tunnels of different sizes were used for the CFD simulation. Detail experimental measurements on air velocity and concent...

This technical note presents a simple, fast, reliable and cheap method to estimate the methane (CH4) production from animals by using the CH4 and carbon dioxide (CO2) concentrations in air near the animals combined with an estimation of the total CO2 production from information on intake of metabolizable energy or heat producing units. By using por...

The investigation was based on a hypothesis that applying an extra pit ventilation system may remove the highly concentrated gases and odours from the headspace above the liquid manure surface. This would improve air quality in the animal occupation zone, and utilising an air purification system to clean the pit-exhaust air may result in a reductio...

The objectives of this paper are to determine the effects of varying the ventilation rates on ammonia emission using three different control strategies: constant inlet opening area, constant inlet air velocity and constant inlet air jet momentum. In addition, methods for estimation of air exchange rates between the headspace and the room are invest...

The purpose of this work is to inquire the potentials of a simplified method of modelling radial inlets in numerical simulation of airflow in mechanically ventilated livestock rooms. This simplified method is based on simulation of an angle section of the entire air volume with starting point in the centre line of the inlet. Using symmetry planes a...

The objective of this work was to investigate the efficiency of a partly pit ventilation system with cleaning of the air exhausted from the pit. The analysis, including Computational Fluid Dynamics (CFD) methods, showed that evacuating and cleaning of 10% of the total ventilation capacity from a pit may reduce the ammonia emission of the system by...

Odor emissions from pig buildings have been the topic for many research projects. However, the fact that the odor emission is dependent on air as transportation medium is far less investigated. Therefore, more comprehensive investigations on the effects of odor release of airflow patterns and ventilation airflow rates are needed. The objective of t...

Climatic conditions in the animal occupied zone (AOZ) of a pig room are important for animal health, comfort and performance. Both practical measurements and numerical simulations could be used to assess the climatic conditions in the AOZ. The objective was to test the possibilities for using pig location patterns based on the real time monitoring...

ABSTRACT Odour annoyance from livestock production is an increasing problem in many countries, and efforts to reduce the odour inconvenience,are necessary to maintain or establish good relations between,animal producers and their neighbours. Ventilation exhaust is usually the most sig- nificant odour source from livestock production and full scale...

Studies of the development of the compact ceiling air jets generated by rectangular wall inlets were carried out. Two types of inlets were applied in the experimental studies. One inlet was designed with an elliptic profile in the contraction section according to the ISO standard for a long-radius nozzle (ISO inlet). Another was a pre-manufactured...

This study investigates different methods to model wall inlets in computational fluid dynamics (CFD) simulations of airflow in livestock rooms. The experiments were carried out in an 8.5 m long, 3 m high and 10.14 m wide test room equipped with a forced ventilation system. Four wall inlets were distributed symmetrically along an end wall 0.5 m bene...

The aim of this work is to develop applicable methods to model wall inlets in numerical simulations of airflow in livestock buildings. Simulations were compared with measurements in an 8.5 m long, 3 m high and 10.14 m wide test room. A prefabricated wall inlet was centred 0.50 m beneath the ceiling and 5.87 m from one side wall of the room. The inl...

This paper describes simulation of airflow and temperature distribution in livestock buildings. Four different configurations of ventilation system have been studied. Low momentum air supply was studied with air supply near the floor and through the ceiling respectively. High momentum air supply was studied in configurations with a slot inlet as we...

The aim of this work was to investigate the influence of pen partitions and heated simulated pigs on airflow in a slot ventilated test room and to evaluate computer fluid dynamics (CFD) as a tool to predict airflow in livestock rooms. To obtain two-dimensional flow in the occupied zone, four guiding plates were mounted beneath the ceiling in the te...

Symmetrical room geometry is not a sufficient condition for the design of a ventilated room where two-dimensional airflows are to be generated. Three-dimensional effects were observed in a symmetrically designed 3 m high by 5 m wide by 8·5 m long test room having a 0·019 m high slot inlet opening under the ceiling.The attached jet velocity profile...

The aim of this work was to investigate the influence of pen partitions and heated simulated pigs on airflow in a slot ventilated test room and to evaluate computer fluid dynamics (CFD) as a tool to predict airflow in livestock rooms. To obtain two-dimensional flow in the occupied zone, four guiding plates were mounted beneath the ceiling in the te...

The effects of internal occupants and supplement heating make up an essential issue for the prediction and control of fresh ventilating air distribution in an enclosure. The influence from livestock is complex, since they are mobile obstacles, producing heat and contaminants in irregular geometry. As a part of the basic studies of these influences,...

This work is part of a project to develop numerical simulation methods for predicting the effect of animals and pen partitions on the airflow in the animal-occupied zone. As a reference case for this, it was desired to create a steady two-dimensional flow near the floor in an empty test room (8·5 m long, 3 m high and 5 m wide). A plane wall jet is...

The design of modem housing systems for farm animals calls for cooperation between scientists within different disciplines. This article describes the design of a new production system for weaned and growing pigs, as well as the analyses and working processes behind its development. The aim of the study was to develop an economically competitive sy...

Summary This paper describes our experiences with Virtual Reality visualisation of CFD results in an immersive environment. The data for visualisation were simulation results of airflow and temperature distribution in livestock buildings. Four different configurations of ventilation system were studied. Low momentum air supply was studied with air...

An investigation of room airflow was carried out in an 8.5 m long, 3 m high and 10.14 m wide test room equipped with an under pressure ventilation system. Four wall inlets were distributed sym- metrically along the end wall 0.5 m beneath the ceiling. To obtain uniform and easily modeled boundary conditions the inlets were designed as rectangular fr...

Air velocity fields and their effect on CO2 distribution in the near floor region were investigated in a full-scale ventilated room with pig simulators and a partition wall. The room was 10 m wide, 3 m high and 8.5 m long. The solid partition wall was 0.8 m high and 10 m wide spanning across the room 5 m from the ventilation inlet wall. Two rows ea...