L. Rong

• PhD
• Professor (Associate) at Aarhus University

Maintaining proper interior thermal condition during transportation is vital for animal welfare and sustainability of livestock supply chain. This study investigated the air temperatures inside a multi-deck naturally ventilated vehicle when transporting weaner pigs under warmer weather condition by using computational fluid dynamics (CFD). Predicti...

Conventionally, the airflow fields outside and inside the naturally ventilated livestock buildings are modelled simultaneously in one computational domain using CFD (Computational Fluid Dynamics). The presence of surrounding buildings, indoor facilities and animals for large scale cattle barns make the required computational power extremely high an...

Transporting pigs poses a significant challenge in maintaining proper interior thermal conditions. This study conducted 36 field trials run in Denmark and collected data from a certified livestock vehicle, during journeys of 8 h and 23 h respectively. This study aims to investigate the air temperature inside a livestock vehicle during the transport...

Field-applied liquid animal manure (slurry) is a significant source of ammonia (NH3) emission, which is harmful to the environment and human health. To evaluate mitigation options, reliable emission measurement methods are needed. A new system of dynamic flux chambers (DFCs) with high-temporal-resolution online measurements was developed. The syste...

The Passive Daytime Radiative Cooler (PDRC) exhibits potential in enhancing building energy conservation due to its high emissivity in wavelength between 8 μm and 13 μm. However, current building energy simulation programs, e.g., EnergyPlus, generally adopt a constant emissivity. To implement the wavelength-dependent PDRC model into EnergyPlus, a r...

Field applied liquid animal manure (slurry) is a significant source of ammonia (NH3) emission, which is harmful to the environment and human health. To evaluate mitigation options, reliable measurements of effects are needed. A new system of dynamic flux chambers (DFC) with high time resolution online measurements was developed. The system was inve...

Animal welfare closely depends on its ability to adapt and thrive in a harmonious relationship with its environment, ensuring both physical and psychological well‐being. Over the years, the welfare of farm animals has gathered global attention and has become increasingly important to the general public and scientific communities. The connection bet...

Within this chapter, a simple ammonia emission model is described that can be used as a design tool for low-ammonia housing systems for pigs. Within this model, ammonia emission is calculated by summation of the ammonia emissions of the different sources that can be distinguished within a pig pen: manure channel(s), slatted floor, and solid floor (...

The surface temperature of a passive daytime radiative cooler (PDRC) can be lower than the ambient temperature without consuming any extra energy. Thus, the technology of the PDRC has attracted the attention of researchers recently. However, most current studies only focused on the short-term performance of the PDRC during sunny and cloudless days....

Computational fluid dynamics (CFD) has been widely used for studying the indoor environment of livestock houses. However, the detailed geometrical models of pigs in commercial pig production houses induce extremely high grid numbers which require huge computational capacity. Therefore, simplifying the pigs in the occupied zone into porous media mod...

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...

Quantifying the conductive heat loss of sows is important in establishing the heat balance equation of sows to evaluate the heat stress because sows spend a significant amount of time lying on the floor. However, previous studies did not offer explicate relationships between the floor heat transfer coefficient (FHTC) and the potential influential f...

Alleviating the heat stress suffered by dairy cows in order to increase their productivity depends on an effective ventilation system. For this reason, this study evaluated the heat mitigating performance of a perforated air ducting (PAD) system with special attention given to significant design parameters (e.g., the shape and size of the orifices...

In laying hen farm, odor measurement and reduction are necessary for clean environment management and human/animal health care. However, limited quantitative data and expensive detection technologies preclude an accurate assessment of odor reduction practices. This study compared the odor prediction ability of three different machine learning model...

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...

Microclimatic conditions affect the thermal comfort and health of sows kept in confined spaces. Individualised ventilation strategies (IV) have been shown to be more effective in providing homogeneous cooling effects and fresh air across the highly sectioned sow houses than conventional ventilation strategies. However, using computational fluid dyn...

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...

Individualized ventilation strategies were more effective in providing homogeneous cooling effect and fresh air across the highly sectioned sow houses than conventional ventilation strategies. However, past studies have primarily concentrated on the physiological reactions of the sows under individualized ventilation ; few of them discussed the per...

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...

Efficient ventilation in urban area can dilute air pollution and remove surplus of heat in summer. The urban wind and thermal conditions are influenced by the interaction between local meteorological condition and urban geometry. This study investigated the impacts of building height, building distance and layout form on outdoor ventilation within...

This study investigated outdoor thermal comfort within 5 × 5 idealized building arrays on five consecutive days by conducting unsteady computational fluid dynamic (CFD) simulations. The dynamic interacting effects of building height topology, building distance and building layout on airflow patterns, spatial distributions and spatially averaged out...

Many CFD simulation studies substitute Animal Occupied Zone (AOZ) as porous media to reduce computation time and resources. With the improved computational capacity, it is now possible to include realistic geometric models of individual animals and partition walls. This study presents a CFD model of a large commercial-sized, hybrid ventilated pig b...

Methods to model animal occupied zones in computational fluid dynamics (CFD) for predictions of air properties are explored. The study was based on CFD analysis supported by experimental validation. Animal occupied zone (AOZ) are modelled as a porous media to reduce the computational cost. Here, the porous media was modelled in two ways. The first...

Ammonia (NH3) concentrations in summer were continuously monitored from three typical laying hen houses of CC (conventional cage), AV (aviary), and NM (natural mating colony cage) with manure belt systems in North China Plain to quantify their emission levels, to characterize the diurnal variations, and to investigate the impact of environmental fa...

Due to the quick development of urbanization, it is important to provide a healthy urban environment for the dweller. Previous studies have obtained valuable conclusions of how to improve the urban airflow distribution under isothermal conditions. How to adopt and interpret those conclusions when considering the solar-induced atmospheric stability...

A partial pit exhaust ventilation (PPEV) system installed below the slatted floor has been widely used in fattening pig barns nowadays in Denmark. Experimental tests showed that annually around 50% of ammonia emissions was collected by PPEV system. However, the percent of emissions collected by PPEV system from different emission sources including...

Previous studies investigated the urban wind airflow under the isothermal condition, solar-induced thermal wall and uniform wall temperature boundary conditions. The differences in spatially-averaged airflow properties among those three boundary conditions have not been investigated yet. This study investigated different scenarios to identify: (1)...

Infrared (IR) photoacoustic spectroscopy (PAS) using band-pass filters is a widely used method for measurement of NH3 and greenhouse gas emissions (CH4, N2O and CO2) especially in agriculture, but non-targeted gases such as volatile organic compounds (VOCs) from cattle barns may interfere with target gases, causing inaccurate results. This study ma...

The selection of sampling bags for odour measurement by olfactometry is critical and challenging since the loss of odorants during storage and transportation is usually high. However, there are no recommendations or limitations on the storage time for the standard Triangle odour bag method used in China. In order to optimise the selection of sampli...

Ventilation for the animal house is important since it is highly linked with the convective heat removal from animals. In this context, the animals as obstacles affect the ventilation airflow and consequently the air distribution within Animal Occupied Zone (AOZ). To study the convective heat transfer (CHT) of animals and the pressure drop (PD) res...

Ammonia emissions from animal production systems are a concern due to their potential adverse effects on the environment. It is important for governments to adjust their policies to control ammonia emissions from animal production. To evaluate and quantify emission factors, process-based modelling is a cost-effective procedure, particularly due to...

Simplified engineering models are essential to design and control natural ventilation, yet there are not many theories that can predict cross ventilation with reasonable accuracy. Models based on the orifice equation are known to be inadequate for large openings, but there is no precise definition of the large opening. In this paper, we show that i...

Infrared photoacoustic spectroscopy (PAS) is a widely used method for measurement of NH3 and greenhouse gas emissions especially in agriculture, but non-targeted gases such as volatile organic compounds (VOCs) from cattle barns may interfere with target gases causing inaccurate results. This study made an estimation of NH3 interference in PAS cause...

Volatile organic compounds (VOC) and hydrogen sulfide are emitted from land spreading of manure slurry to the atmosphere and contribute to odour nuisance, particle formation and tropospheric ozone formation. Data on emissions is almost non-existing partly due to lack of suitable quantitative methods for measuring emissions in full scale. Here we pr...

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...

The use of computational fluid dynamics (CFD) to study the airflow within farm animal buildings is increasing. The choice of turbulence model within CFD is generally considered to be important due to the approximations of the turbulence in varied scales. Although some studies have been conducted on evaluations of turbulence models in simulation of...

The thermal comfort of pigs is strongly correlated with the air motion around the pigs. In a pig production building, it is the ventilation system that influences the indoor air distribution significantly. In the ventilation system design, air inlet is considered to be important on the air motion in room. In this study, the Response Surface Methodo...

It is recognized that increasing the local air speed in the animal occupied zone (AOZ) is one of the effective approaches to decrease the heat stress of pigs. To predict the effects of the air speed in an AOZ, knowledge of the relationship between convective heat loss and air speed is essential. In this study, the convective heat losses from pig mo...

Evaporative cooling pad are widely used in poultry production houses in hot and arid climate to provide an appropriate indoor thermal conditions for animals. Currently, the main challenge of this system is to maintain the indoor thermal conditions stable so that the productivity is ensured. This study used wind tunnel measurements to investigate th...

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.,...

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

Under hot climatic conditions, heat stress of the animal is a general concern in livestock farming. To reduce the heat stress, an important approach is ensuring a suitable air speed in the animal occupied zone (AOZ) to increase convective heat removal for animals. Therefore, the relationship between convective heat transfer and air speed is essenti...

There is increasing tendency to use Computational Fluid Dynamics (CFD) method in study of flow distributions in farm animal buildings. Turbulence models are generally considered to be important on the results due to the approximations of the turbulence in varied scales. Although some studies have been conducted on the evaluation of turbulence model...

It is recognized that increasing the local air speed in the animal occupied zone (AOZ) is one of the effective approaches to decrease the heat stress of pigs. To predict the effects by varying the air speed in AOZ, knowledge of convection heat loss and air speed is essential. In this study, the convective heat loss from pig is studied based on nume...

Performance of pig production is strongly affected by indoor thermal conditions, especially in hot weather when ventilation running in full capacity and indoor temperature increases following out temperature rises. Generating higher air speed in animal occupied zones of a ventilated livestock building is one of the methods that can reduce animals'...

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...

The main objective of this report was to review and gather scientific information and data from the literature to test the assumption that the ammonia emission from a pig house slurry pit and outside storage is more dependent on the area of slurry surface than on the produced quantity or slurry (with the same ammoniacal nitrogen concentration) in t...

In order to model and predict ammonia emissions from animal houses, it is important to determine the concentration on the emission surface correctly. In the current literature, Henry's law is usually used to model the mass transfer through the gas–liquid surface (e.g. manure or aqueous solution). The objective of this study is to investigate the ac...

A diffuse ceiling inlet system is an air distribution system which is supplying the air through the whole ceiling. The system can remove a large heat load without creating draught in the room. The paper describes measurements in the case of both cooling and heating, and CFD predictions are given for the heating case.

This paper describes a benchmark test which can be used for tests of CFD predictions of room air distribution. The benchmark describes a box-like room with a supply slot along the side wall. Laser-Doppler measurements and hot-wire measurements are given for comparison with the obtained CFD predictions both for isothermal flow and for nonisothermal...

This paper reports the results of an investigation, based on fundamental fluid dynamics and mass transfer theory, carried out to obtain a general understanding of ammonia mass transfer from an emission surface. The effects of airflow and aqueous ammonium solution temperature on ammonia mass transfer are investigated by using computational fluid dyn...

In this paper, a 2D simulation for a typical livestock building is performed to assess the ammonia emission removal rate to the atmosphere. Two geometry models are used and compared in order to represent the slatted floor. In the first model the floor is modeled as a slatted floor and in the second model the traditional porous media is used. The re...

The present study performed a series of experiments in a wind tunnel to investigate the impact of velocity, turbulence intensity and liquid-air temperature difference on ammonia emission rates. Decreasing velocity, turbulence intensity and liquid temperature are shown to reduce the ammonia emission rates. The emission rates are more sensitive to th...

Variations of air exchanges in slurry pit with four angles of an environmental deflector, namely 0° (parallel to the side wall or without deflector), 30°, 45° and 90°, were investigated using a tracer gas method. The investigations were performed in a two-dimensional ventilation chamber in the Air physics Lab, University of Aarhus. Ventilation rate...

Airflow patterns and airflow rate have an important influence on contaminant distribution in swine buildings. The objective of this paper is to model and evaluate the effect of airflow rates and airflow patterns on CO2 concentration distribution. Contaminant sources are assumed to be modeled as a constant concentration on the manure surface. Three...