In this paper, the indoor environmental quality for the commuter train space was analyzed for assumingthe load factor of seat capacity to be a parameter of analysis. Especially flow fields, temperature and airquality distributions in vehicle space were analyzed by using CFD technique. Furthermore, it reports onthe result of examining the controllability of indoor climate in the vehicle when the displacementventilation system was applied in it.
In this study the question whether or not and to what extend ventilation and air cleaning can contribute to the reduction of exposure to environmental tobacco smoke in the hospitality industry is answered. First a literature review on ventilation and air cleaning technologies has been executed. Unfortunately, only a few papers reporting experimental data from the hospitability industry were available to answer the proposed question. Therefore a model describing the effect of different ventilation systems and building layouts has been set up.
How to avoid or reduce the influence of suddenly released contaminant when emergency occurs ? A 3D Full scale room with displacement and mixing ventilation system is numerically studied assuming contaminant released at certain positions in the room. IACS is adopted as an index that can be applied to determine ventilation strategy with the aim of defending indoor environment against contamination.
The paper presents an extension of a two-equation turbulence model to predict the airflow fordisplacement ventilation systems. First, every flow effect is investigated separately natural convection along a vertical wall and above a person as well as mixed convection at the floor. Second, a CFD analysis of a test room is compared to full scale measurements. The modified two-equation turbulence model leads to a good agreement of the measurements and the calculations.
This paper examines airflow in rooms for a displacement ventilation system using threedimensionalCFD. A parametric study is executed for a typical office room with a dimension of 6m by 6m by 3m height according to a variety of supply air velocities, supply air temperatures and heat sourceconditions. A finite volume method and standard k- e turbulence model is employed to solve the governing equations. As a result, the temperature field in the modeled room for a displacement ventilation system is concluded according to a variety of the above parameters.
This paper presents the results of the application of building thermal simulation in the design of anew concert hall and refurbishment of interior spaces in the So Francisco Convent in Coimbra, Portugal. The proposed design uses displacement ventilation in all spaces, mechanically driven in the auditorium and hybrid in the convent rooms. A displacement ventilation model, recently implemented in EnergyPlus, is used to predict energy consumption and thermal comfort.
Experiences from cleanroom installations has frequently shown that displacement ventilation has a much higher efficiency than mixing ventilation with respect to particle and CO2 reduction, cooling efficiency etc. Another cleanroom experience is that low particle concentration benefits asthma and allergy sufferer. Low particle concentrations reduces the impact of other pollutants and enhance the quality of life for everybody. In an office, the level of discomfort this means less tiredness, better concentration and lower absenteeism.
Airborne particle concentrations of 20 nm to 10 µm particles were studied in two similar classrooms in a school. One classroom was ventilated by mixing ventilation with supply air filtration and one by displacement ventilation without supply air filtratio
Large spaces with high thermal loads and high air flow rates air conditioned by displacement flowsometimes require air supply through the raised floor. One favoured solution is to cover the perforated floor by an air permeable carpet. Successful solutions of this type of air outlets exist in many buildings in Germany since many years and work successfully. But design and installation require some knowledge which partly may have been lost in recent years. In newer buildings many difficulties appeared.
This paper presents a simple model for vertical temperature profile and heat transfer predictionin displacement ventilation. The fully-mixed room air approximation that is currently used in most whole building analysis tools is extended to a three node approach, with the purpose of obtaining a first order precision model for displacement ventilation systems. The use of three nodes allows for improved prediction of thermal comfort and overall building energy performance in low energy cooling strategies that make use of unmixed stratified ventilation flows.
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