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.
The values of the normalized concentration in the occupied zone (Cn) in an office space arecalculated by CFD for five different ventilation systems and the minimum ventilation rate which maintains the average concentration in the occupied zone under the regulated value is analyzed. Energy consumptions associated with the change in ventilation rate are analyzed. In this analysis, for most ventilation systems, the value of Cn is around 1.0, but for large circulation flow ventilation systems it changes greatly depending on the supply inlet velocity and temperature.
The distribution of the humidity in a dwelling unit is the key factor determining the condensationrisk and the mold growth, as well as the dryness problem. As the first stage of the research project aiming at the understanding and the solutions of the above problems, the experiment on humidity distribution in multiple rooms with the simulated occupancy was carried out in a full-scale research house. The effects on the humidity distribution of the ventilation, etc. are described and compared with the numerical predictions.
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
Nowadays, the need to keep indoor air quality under control is widely known due to the fact that people spend most of their time indoors. In order to show a useful working-tool this paper aims to present a guide to evaluate indoor air quality. This work was structured in the following stages: visual inspection, check list, data analysis, experimental measurements of the physical and chemical pollutants and an analysis of the improvement of indoor environmental quality.
The performance of a passive cooling system was evaluated as part of design works for theproject of an auditorium. The passive cooling system incorporates an array of buried pipes together with a solar chimney. The natural ventilation is enhanced with the help of the solar chimney and fresh air is cooled by circulation within the buried pipes. The application of this system to the acclimatization of an auditorium was evaluated. A model was developed on this purpose, which allows foreseeing the temperature and relative humidity of the air in the auditorium.
The effects of exterior thermal transmission modeling for walls and a roof on the airconditioning heat load prediction for a large space building were analyzed using a coupled simulation of convection based on CFD, radiation and conduction. Three cases were simulated: first, a simplified model using sol-air temperature (SAT) as outdoor boundary conditions; second, a rigorous model where both outdoor and indoor spaces were calculated simultaneously; and, third, using sol-air temperature modified by the results of the second case.
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.
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