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Contaminant transport in the aircraft cabin became one of the most vital issues that should be concerned; because there are over 4.6 billion passengers choose travelling by aircrafts, as they are safe, comfortable, and fast. In addition, aircrafts manufacturers aim to produce large aircrafts that are able to contain the highest number of passengers. Airborne diseases, for example, SARS and Influenza are considered the most fatal diseases, which can transport in the cabin rapidly, due to the large number of particles or droplets in one cough or sneeze as well as the velocity of these particles, as a consequence these characteristics, airborne pathogens such as cough and sneeze can spread and reach great number of passengers at one time. This study shows the result of simulation of cough droplets that produced from an infected moving passenger using computational fluid dynamics simulation (CFD) and dynamics mesh and discrete phase models in ANSYS FLUENT program, also it reveals the effects of these produced droplets on the other passengers inside the cabin. The results reveals that, cough droplet that produced during the movement of the passenger are extremely detrimental, as it could spread to a distance more than 4 meters along the cabin, moreover, it affected too many passengers in the cabin. [ABSTRACT FROM AUTHOR]

Thermal comfort in automobile cabin can affect drivers and passenger's health, performance and comfort. Due to spatial and temporal variation of state variables and boundary conditions in the automobile cabin, the heating, ventilating and air-conditioning (HVAC) does not have to be designed to provide a uniform environment, especially because of individual differences regarding to physiological and psychological response, clothing insulation, activity, air temperature and air movement preference, etc. The main objective of this research is to study the air flow regimes and thermal comfort in automobile cabin using computational fluid dynamics (CFD) software. For this purpose, the CFD software from ANSYS Inc., called FLUENT 17.2, is employed. In which the solar load model is embedded s2s (surface to surface) as a solar radiation model. The CFD modeling techniques solved the continuity, momentum and energy conservation equations in addition to standard k - e model equations for turbulence closure. Meshing is processed around 4.0 million unstructured tetra-elements approximately. The performance of the air conditioning system is characterized by airflow regimes (air temperature, air velocity, relative humidity, PMV and PPD contours), the present work is focus on the effect of air terminal shape of Hvac system, two configurations are used case (1) and case (2). Case (1) is the existing design of air terminals of the HVAC system of the selected car (Skoda Superb), the air terminals are in rectangular shape. While case (2) are in circle shape. [ABSTRACT FROM AUTHOR]

The design criteria of air conditioning in ships became more refined especially with the development of shipping industry, crew's health and personnel comfort strongly affected by inside thermal environment in air-conditioned spaces, the distribution of air temperature and relative air velocity should consider the presence of occupants and other factors such as food vapors and heat from other sources. This thesis focuses on analyzing indoor thermal comfort inside a hall in a cruise ship through numerical investigation of changing the location and distribution of air supply and air extract grilles on air properties such as temperature and velocity. The present investigation studies thermal comfort in a dining hall at the top floor of a cruise ship, which is basically, used as multifunction hall. Five suggested design alternatives were studied and in each case the location, dimensions and even number of air supply and air extract grills and boundary conditions changed to assess the effect of these parameters on thermal comfort levels for occupants. The effectiveness of thermal comfort on occupants is portrayed through discussing velocity contours, temperature patterns, local relative humidity, PMV and PPD based on Fanger's model at various locations in the cruise ship. The numerical investigation has been performed with the aid of computation fluid dynamics technique (CFD) which is commercially available as (ANSYS 17.2) with number of mesh elements around 5,000,000. The simulation has been carried out using different boundary and operating parameters of solar energy and climatic conditions, the paper ends with a brief summary of conclusions and design recommendations. [ABSTRACT FROM AUTHOR]

Renewable energy resources and solutions are the main concern, nowadays; lack of energy is the future nightmare .The world HVAC associations are implementing codes from the beginning of the design stage for energy savings. The research paper investigates an existing energy problem in a district cooling plant in Egypt. The existing price for electricity is high which affected the price of the ton refrigerant produced by the district cooling plant which is sold to all the buildings in areas of the district. The research investigates and make use of an artificial lake and propose that the lake is a solution as heat sink instead of the existing cooling towers. The methodology for the above research was carried out by site temperature measurement and energy modeling perspective for a sample chiller of the district cooling plant. [ABSTRACT FROM AUTHOR]

The selection and control of the cooling, ventilation and air conditioning systems to provide controlled internal conditions in historic and heavy weighted buildings requires knowledge not only of the effectiveness of the proposed system providing the required conditions quickly and efficiently, but also on the long term effects of the system and any sudden fluctuations of the internal climatic conditions on the comfort and on the life of the building envelope itself and any work of arts that are there. Places of worship, are of high spiritual nature and commonly architecturally elite. The occupants are usually praying either standing or bowing, kneeling and sitting as well. The level of activities should be accounted for the thermal load calculations. The present work is a numerical investigation to point out the factors affecting the air outlets position, size and orientation in various places of worship. A commercial package was utilized with more than 1000000 tetrahedral grid volumes. The activity level, position of occupant and arrangement in the designated spaces are investigated. The performance of the air conditioning system is characterized by air flow patterns, temperature and relative humidity contours as well as the PMV and PPD. Three examples are shown here for an archaeological mosque of moderate size (900 prayers) in Cairo, Egypt, The grand mosque extension project (500000 prayers) in 'Mecca', Saudi Arabia, And the St. Mary's Orthodox Church (450 prayers) in Cairo, Egypt. The paper ends with a brief summary of conclusions and guidelines for design remarks. [ABSTRACT FROM AUTHOR]

This paper is devoted to critically analyze the air distribution, thermal patterns and thermal comfort parameters in an air-conditioned enclosure. A computational fluid dynamics model is developed to examine the air flow characteristics of a room with different supply air diffusers at different blade angles. The work focuses on airflow patterns, thermal behavior in the room where few number of occupants. As an input to the full-scale 3-D room model, a 3-D air supply diffuser is numerically modeled to supply air at different directions into the room. Air distribution effect on thermal comfort parameters was investigated depending on changing the air supply diffusers angels. The thermal comfort predictions through this work were based on the PMV (Predicted Mean Vote) model and the PPD (Percentage People Dissatisfied) model, the PMV and PPD were estimated using Fanger's model. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics model is developed to examine the air flow characteristics of a room with different supply air diffusers. The paper is devoted to numerically investigate the influence of location and number of air supply and extracts openings on air flow properties in a typical seating room. The work focuses on air flow patterns, thermal behavior in the room where few number of occupants. As an input to the full-scale 3-D room model, a 2-D air supply diffuser model that supplies direction and magnitude of air flow into the room is developed. Air distribution effect on thermal comfort parameters was investigated depending on changing the air supply diffusers type, angels and velocity. Air supply diffusers locations and number were also investigated. The pre-processor Gambit is used to create the geometric model with parametric features. Commercially available simulation software "Fluent 6.3" is incorporated to solve the differential equations governing the conservation of mass, three momentum and energy in the processing of air flow distribution. Turbulence effects of the flow are represented by the well developed two equation turbulence model. In this paper work, the so-called standard k-ε turbulence model, one of the most widespread turbulence models for industrial applications, was utilized. Basic parameters included in this work are air dry bulb temperature, air velocity, relative humidity and turbulence parameters are used for numerical predictions of indoor air distribution and thermal comfort. The thermal comfort predictions through this work were based on the PMV (Predicted Mean Vote) model and the PPD (Percentage People Dissatisfied) model, the PMV and PPD were estimated using Fanger's model. [ABSTRACT FROM AUTHOR]

This paper reviews the previous attempts to evaluate the Indoor Air Quality (IAQ), investigates previously proposed IAQ factors and analyses the evaluation methods of these factors. The present work introduces, also, a new hypothesis of the optimum HVAC airside system design of the surgical operating theatres to achieve the comfort and hygiene levels. The present work is devoted to propose and formulate a new scale capable of adequately evaluating the airflow pattern in the surgical operating theatres. The proposed new scale is proposed to cover the local and overall air quality evaluations. A new Neuro fuzzy technique was applied to derive measures for indoor air quality indices. Indoor Air Quality (IAQ) is more critical in healthcare facilities due to the dangerous microbial and chemical agents present and the increased susceptibility of the patients. Hospitals and other healthcare facilities are complex environments that require ventilation for comfort and to control hazardous emissions. Surgical operating theatre is the most important and complex zone in the hospital, and requires more careful control of the aseptic conditions of the environment. Most of the previous researches aiming at evaluating the IAQ were based on the evaluation of the air distribution depending on the residence and leaving age of the air supplied to the enclosure. Other attempts were also reported to indicate the effectiveness of contaminant removal by the entire airflow pattern as an indication to the IAQ. This paper recommends some designs of the supply air outlets to provide the vertically downward airflow as a practical solution. The near ceiling and near floor extract ports are to be used instead of the hypothetical complete floor extract as a practical solution. [ABSTRACT FROM AUTHOR]

In this paper Artificial Neural Networks (ANN) are used to predict the energy consumption in an air conditioned administrative building. The model is constructed by a simulation package called Design Builder where EnergyPlus is the core program which is provided with the weather data for Cairo and simulated to produce the system performance hourly data (Total energy consumption of the Building, Chiller energy consumption, etc). Different experiments and cases are done to evaluate the performance of the prediction at different types of inputs introduced to the ANN. Different combinations of Input parameters and different structures of ANN are used. A feed forward backpropagation structure is used for modeling which is trained by Levenberg Marquardt algorithm. It was found that changing the input data which is introduced to the ANN has a great effect on its predicting ability. Different performance parameters are defined for assessment of the ability of the trained neural network such as Root Mean Square Error and coefficient of variation where at the best case they became 4.014KW and 0.042. This will introduce the ANN capability and will show the effect of different parameters and conditions on its predictability. This model can also be potentially used for optimization of building control systems. [ABSTRACT FROM AUTHOR]

The definition of a good indoor climate is important to the success of a passenger rail coach, not only because it will decide its energy consumption and thus influence its sustainability but also because good comfort for long journeys is essential. The intention is to use the results to optimize the control of the ventilation system to provide an indoor climate that passengers will find comfortable. The results of this study show how passengers' thermal comfort was affected by changing the supplied air conditions. This paper primary discusses and analyzes the simulation of the air flow and thermal patterns in a Subway station. Numerical simulation of a typical model is presented. Modifications were applied to the numerical model to show the improvement of the thermal comfort level. The pre-processor Gambit is used to create the geometric model with parametric features. Commercially available simulation software "Fluent 6.3" is incorporated to solve conservation of mass, momentum and energy in the processing of air distribution, and to analyze turbulence affection combined heat transfer on air distribution. In this thesis work, the socalled standard k-ε turbulence model, one of the most widespread turbulence models for industrial applications, was utilized. Basic parameters included in this work are air temperature, air velocity, relative humidity and turbulence parameters are used for numerical prediction of indoor air distribution. Measurements of air velocity, and temperature were undertaken in a plane perpindicular to the supply diffuser. These values were then compared to the obtained results from the simulated cases. The thermal comfort prediction through this work was based on the PMV (Predicted Mean Vote) model and the PPD (Percentage Predicted Dissatisfied) model, the PMV and PPD were estimated using Fanger's model. [ABSTRACT FROM AUTHOR]

All countries face the challenge of assuring secure, reliable energy services in the coming decades. Almost all countries in Africa have experienced interruption of some form of energy supply in recent years. Tension in oil and gas markets, changing rainfall patterns, expanding demand, as well as internal technical, managerial and financial problems, have caused crisis in the availability of fuels or electricity. Furthermore, the challenges of climate change are putting increasing pressure on energy sector development in Africa. A large majority of African countries are heavily dependent on energy imports. Even the African countries that are major exporters of energy -- petroleum, gas, and electricity or biomass fuels -- must import at least one crucial element of their energy mix. The improvement of economic governance and the investment climate are essential elements to build Africa's economic strength and allow Africa to move away from continuous donor support and find its place in global markets. Integrating national systems into regional networks will foster sustainable economic growth and development and improve energy security. The international economic crisis has highlighted the importance of regional integration as a means to aid those countries that rely on a limited range of energy supplies. Solar, wind and other RES as well as the thermal and electrical energy are explored in our continent and the present work briefly outlined the scope, goals, methodologies and applications. Samples and case studies are shown. [ABSTRACT FROM AUTHOR]

In this paper, three dimensional model of the subway station was built, a mathematical model was developed based on the standard κ-[variant_greek_epsilon] turbulence model, and computational fluid dynamics (CFD) simulations for the air conditioning systems were performed to clarify the conditions of the temperature fields. Comparisons were made between different cases of air-conditioning with varying passengers densities showing the degree of human comfort within the space in each case. Commercially available simulation software 'Fluent 6.3' is incorporated to solve conservation of mass, momentum and energy in the processing of air distribution, and to analyze turbulence affection combined heat transfer on air distribution. In this thesis work, the so-called standard κ-[variant_greek_epsilon] turbulence model, one of the most widespread turbulence models for industrial applications, was utilized. Basic parameters included in this work are air temperature, air velocity, relative humidity and turbulence parameters are used for numerical prediction of indoor air distribution. [ABSTRACT FROM AUTHOR]

The present paper is devoted to discuss and analyze the simulation of the pollutant transmission characteristics in an office room with infectious person. The activity level, position of occupant and arrangement of air supply and exhaust grills in design spaces were investigated. It also investigated the ability of the ventilation system to reduce the risk of infection inside such rooms. Six different cases of an office room were studied in this work. The aim of the current work is to investigate which configuration is the best for reducing the danger of infection, besides temperature, velocity and relative humidity distributions. The sixth case which contains partition wall and supply airflow from the floor showed the best control of infection between all cases and good thermal comfort. [ABSTRACT FROM AUTHOR]

The vortex tube is a special industrial and refrigerator device that uses pressurized air as a working medium. The pressurized air is injected tangentially to the tube forming a swirling motion so that two regions can be exists; one is warm and the other is cold. This process of air separating called energy separation that based on the Ranque-Hilsch effect. Over years many hypotheses were proposed to demonstrate how this energy separation happens. However, the available hypotheses explained a part of the energy separation phenomena, but the nature of energy separation is still not clear completely. Vortex tubes have become needed in cooling applications in welding and cutting machines, natural gas liquefaction and cooling vests, where essential features like compactness, safety, and low equipment cost are required. To study and hence improve the vortex tube cooling performance, a three dimensional simulation of counter-flow vortex tube was computer-generated using Ansys CFD package. To obtain a flow solution in the refrigerator vortex tube, the k-Turbulence Model is selected. Selection of k- turbulence model refers to that it is the greatest well-matched turbulence model with the experimental results. Assessment of validation was attained using a standard vortex tube product simulation and compared to published experimental results. This paper aims to study the impact of some important parameters variation on refrigerating performance. These parameters are injection jets profile, inlet nozzles number, inlet pressure, cold mass fraction (CMF) and divergence angle of the refrigerator vortex tube was studied and modified to give better cooling performance. This study results to enhance the cooling performance of the refrigerator vortical tube by altering the geometry and operating conditions what enhance the resulted temperature separation effect and coefficient of performance. [ABSTRACT FROM AUTHOR]