A CFD SIMULATION OF PM1 AND CO AIR CONTAMINANTS IN A BUS PASSENGER COMPARTMENT

2015 ◽  
Vol 77 (30) ◽  
Author(s):  
Noor Emilia Ahmad Shafie ◽  
Haslinda Mohamed Kamar ◽  
Nazri Kamsah
Keyword(s):  
Carbon Monoxide ◽  
Particulate Matter ◽  
Distribution Systems ◽  
Cfd Simulation ◽  
Ventilation System ◽  
Air Distribution ◽  
Passenger Compartment ◽  
Displacement Ventilation ◽  
Three Dimensional Model ◽  
Air Contaminants

Air distribution systems inside a bus compartment are important for providing healthy and comfortable environment for passengers. Lack of ventilation inside the bus passenger compartment causes an increase level of air contaminants concentration. Particulate matters and carbon monoxide are indoor air contaminants which can affect the passenger’s health such as respiratory problem and lung cancer. This article reports the results of a CFD simulation on transport of carbon monoxide and particulate matter 1 inside a passenger compartment of a university’s shuttle bus. Fluent CFD software was used to develop a simplified three-dimensional model of the bus passenger compartment. Flow analysis was carried out using RNG k-e turbulent model for air flow, discrete phase and species transport for the air contaminants. Four variations of ventilation system namely two mixing ventilation types, combined mixing with displacement ventilation and combined mixing ventilation with underfloor air distribution was examined. The CFD simulation results show that the use of the combined mixing and displacement ventilation and also the combined mixing and underfloor ventilation types are capable of reducing the concentration of carbon monoxide and particulate matter 1 inside the bus passenger compartment by 81% and 54%, respectively.

Energy Use Comparison of Air Distribution Systems Serving a Section of a School Building

2012 ◽  
Author(s):  
Stillman Jordan ◽  
Randall D. Manteufel
Keyword(s):  
Total Energy ◽  
Distribution System ◽  
Energy Recovery ◽  
Distribution Systems ◽  
Energy Savings ◽  
Ventilation System ◽  
Space Distribution ◽  
Air Distribution ◽  
Displacement Ventilation ◽  
Humid Climate

An optimal air distribution design accomplishes both comfort and ventilation requirements while consuming as little energy as possible. This paper analyzes four different air distribution systems and technologies including single duct variable air volume air handlers, chilled beam cooling systems, total energy recovery wheels, displacement ventilation, and dedicated outside air systems; in an effort to determine the best air distribution system for a representative section of a school in hot and humid climate. The effectiveness of the air distribution systems is evaluated by analyzing how the different technologies take advantage of the natural convective properties of air to create a comfortable environment for the occupied region of the space. Distribution effectiveness and energy consumption must be weighed against considerations such as system complexity and ease of operation. This paper compares several alternative air distribution systems to a baseline single inlet VAV system that is commonly used in new schools designed today. Calculations show that the total energy recovery wheels result in a 16% energy savings over the baseline air distribution system because of the large amount of outside air required in school buildings. Chilled beams are not well suited for schools because of the large amount of outside air required by the space and the sophisticated design and operation needed to prevent condensation from occurring at the chilled beam. The results show that the air distribution system that consumes the least amount of energy is a displacement ventilation system. The system also inherently promotes better indoor air quality as it allows air to naturally rise out and return out of the space with minimal mixing of contaminates that may be recirculated within the room for others to breath. The displacement ventilation system’s overall energy savings of 20% over the baseline is mainly attributed to its total energy recovery wheel and the system’s ability to drastically reduce the cooling load seen by the air cooled chiller by effectively ventilating spaces using less outside air.

scholarly journals Experimental Investigation of the Ventilation Performance of Different Air Distribution Systems in an Office Environment—Cooling Mode

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1354 ◽  
Author(s):  
Arman Ameen ◽  
Mathias Cehlin ◽  
Ulf Larsson ◽  
Taghi Karimipanah
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Ventilation System ◽  
Impinging Jet ◽  
Air Distribution ◽  
Displacement Ventilation ◽  
Cooling Mode ◽  
Distribution Method ◽  
Ventilation Performance ◽  
Velocity Turbulence

The performance of a newly designed corner impinging jet air distribution method with an equilateral triangle cross section was evaluated experimentally and compared to that of two more traditional methods (mixing and displacement ventilation). At nine evenly chosen positions with four standard vertical points, air velocity, turbulence intensity, temperature, and tracer gas decay measurements were conducted for all systems. The results show that the new method behaves as a displacement ventilation system, with high air change effectiveness and stratified flow pattern and temperature field. Both local air change effectiveness and air exchange effectiveness of the corner impinging jet showed high quality and promising results, which is a good indicator of ventilation effectiveness. The results also indicate that there is a possibility to slightly lower the airflow rates for the new air distribution system, while still meeting the requirements for thermal comfort and indoor air quality, thereby reducing fan energy usage. The draught rate was also lower for corner impinging jet compared to the other tested air distribution methods. The findings of this research show that the corner impinging jet method can be used for office ventilation.

CFD Simulation of Particle Transport and Dispersion in Indoor Environment by Human Walking

2012 ◽  
Author(s):  
Iman Goldasteh ◽  
Goodarz Ahmadi ◽  
Andrea Ferro
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Study Data ◽  
Turbulent Dispersion ◽  
Experimental Chamber ◽  
Indoor Environments ◽  
Three Dimensional Model ◽  
Particle Resuspension

Particle resuspension is an important source of particulate matter in indoor environments that significantly affects the indoor air quality and could potentially have adverse effect on human health. Earlier efforts to investigate indoor particle resuspension hypothesized that high speed airflow generated at the floor level during the gate cycle is the main cause of particle resuspension. The resuspended particles are then assumed to be dispersed by the airflow in the room, which is impacted by both the ventilation and the occupant movement, leading to increased PM concentration. In this study, a three dimensional model of a room was developed using FLUENT™ CFD package. A RANS approach with the RNG k-ε turbulence model was used for simulating the airflow field in the room for different ventilation conditions. The trajectories of resuspended particulate matter were computed with a Lagrangian method by solving the equations of particle motion. The effect of turbulent dispersion was included with the use of the eddy lifetime model. The resuspension of particles due to gait cycle was estimated and included in the computational model. The dispersion and transport of particles resuspended from flooring as well as particle re-deposition on flooring and walls were simulated. Particle concentrations in the room generated by the resuspension process were evaluated and the results were compared with experimental chamber study data as well as simplified model predictions, and good agreement was found.

scholarly journals A REVIEW OF AIR DISTRIBUTION PATTERNS IN SURGERY ROOMS UNDER INFECTION CONTROL FOCUS

2005 ◽  
Vol 4 (2) ◽  
Author(s):  
M. L. Pereira ◽  
A. Tribess
Keyword(s):  
Distribution Systems ◽  
Control Strategies ◽  
Ventilation System ◽  
Distribution Patterns ◽  
Infection Process ◽  
Air Distribution ◽  
Detailed Knowledge ◽  
Surgical Infections ◽  
Airborne Contamination ◽  
Wide Range

The problem of airborne contamination in surgical infections still raises discussion. The success of the aseptic methods and the use of medicines for the combat of infections are making most surgeons contempt the danger of the aerial particles course. A detailed knowledge of the characteristics of the contamination sources and of the ventilation system performance used at surgery rooms is necessary to guarantee that the ventilation system supplies the pollutant control in ventilation rates that assure the health and the comfort of the occupants. There are many configurations of air distribution systems and a wide range of potential conditions inside a surgery room that are influenced by their performance. In the same way, it is evident the lack of information in the literature regarding which characteristics of the systems of air treatment have stronger influence on the amount of particles in suspension. This paper provides a review of the distribution patterns and air movement at surgery rooms, describing the importance of airborne particles in the infection process, making a comparative analysis of the efficiency of microbiological control of the main airflow systems, identifying and demonstrating the control strategies that can reduce the risks of airborne contamination in surgical infections.

EFFECTS OF VENTILATION SETUPS ON AIR FLOW VELOCITY AND TEMPERATURE FIELDS IN BUS PASSENGER COMPARTMENT

2015 ◽  
Vol 77 (30) ◽  
Author(s):  
Noor Emilia Ahmad Shafie ◽  
Haslinda Mohamed Kamar ◽  
Nazri Kamsah
Keyword(s):  
Flow Velocity ◽  
Air Temperature ◽  
Numerical Study ◽  
Air Flow ◽  
Ventilation System ◽  
Temperature Fields ◽  
Passenger Compartment ◽  
Three Dimensional Model ◽  
Air Flow Velocity ◽  
Ventilation Setup

A bus compartment requires a good ventilation system to provide sufficient fresh air and a uniform air flow to passengers. This article presents a numerical study using CFD method to investigate the effects of using different ventilation setups on the air flow velocity and temperature distributions inside a passenger bus. Fluent software was used to develop a simplified three-dimensional model of a quarter section of a bus passenger compartment. Turbulent flow simulation was carried out based on a standard k-epsilon model to predict the distributions of air temperature and velocity inside the passenger compartment. The effects of two ventilation setups, namely mixing and displacement ventilations on the air temperature and air flow velocity distribution were also examined. Results of CFD simulations show that the displacement ventilation setup results in more uniform distribution of air flow velocity and air temperature inside the bus passenger compartment.

scholarly journals A REVIEW OF AIR DISTRIBUTION PATTERNS IN SURGERY ROOMS UNDER INFECTION CONTROL FOCUS

2005 ◽  
Vol 4 (2) ◽  
pp. 113 ◽  
Author(s):  
M. L. Pereira ◽  
A. Tribess
Keyword(s):  
Distribution Systems ◽  
Control Strategies ◽  
Ventilation System ◽  
Distribution Patterns ◽  
Infection Process ◽  
Air Distribution ◽  
Detailed Knowledge ◽  
Surgical Infections ◽  
Airborne Contamination ◽  
Wide Range

The problem of airborne contamination in surgical infections still raises discussion. The success of the aseptic methods and the use of medicines for the combat of infections are making most surgeons contempt the danger of the aerial particles course. A detailed knowledge of the characteristics of the contamination sources and of the ventilation system performance used at surgery rooms is necessary to guarantee that the ventilation system supplies the pollutant control in ventilation rates that assure the health and the comfort of the occupants. There are many configurations of air distribution systems and a wide range of potential conditions inside a surgery room that are influenced by their performance. In the same way, it is evident the lack of information in the literature regarding which characteristics of the systems of air treatment have stronger influence on the amount of particles in suspension. This paper provides a review of the distribution patterns and air movement at surgery rooms, describing the importance of airborne particles in the infection process, making a comparative analysis of the efficiency of microbiological control of the main airflow systems, identifying and demonstrating the control strategies that can reduce the risks of airborne contamination in surgical infections.

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