Evaluation of ventilation system efficiency using CFD analysis

This paper deals with the development of 2 approaches for the modelling of the transport of gaseous pollutant with CFD code Fluent. The pollutant is either considered as a scalar and modelled with a transport equation, or it is described through species transported modelling. The 2 methods are presented and the results compared to those obtained from an experiment made in a test cell with tracer gas SF6.

Predictions of flow, turbulence, heat-transfer and air humidity patterns in operating theatres

Advances in infection control practices include improved operating room environment (airflow velocity, turbulence level, temperature, and relative humidity). Operating theatres are complex spaces. CFD modelling is a powerful tool to enhance the knowledge of the air characteristics. The 3DHVAC program was used to predict the performance of HVAC system design in operating theatres of a 1200-beds Egyptian modern teaching hospital.

Individually controlled local heating

For workers sharing the same office, there is normally a need for slightly different temperatures to fit their own optimal thermal comfort. In a laboratory experiment with thermal manikin, local radiant heaters have been placed behind office chair , providing heat at their backs, shoulders and necks .
The heat loss from the whole body or from specific body segments was measured during the experiment. The system proved efficiency for keeping the heat balance of the body and reducing the sensation of draught.

Individually control by individual VAV

Concerning thermal comfort (number one complaint in most offices), the range of occupants needs is very wide. An individual control ventilation system based on VAV (varying air velocity) and integrated into desk was installed in a bank in 20 work areas. The article describes several possible arrangements of this system and mentions air temperatures and flow rates to achieve individual thermal comfort as determined from a preliminary study with a mannequin in laboratory.

CFD Study of the micro-climate around human body with inhalation and exhalation

This paper deals with the CFD (Computational Fluid Dynamics) method used for the analysis of the micro-climate surrounding the human body. The airflow characteristics of inhalation and exhalation are analysed under both steady and unsteady breathing conditions. The various examples given in this report make clear that CFD is a very effective and powerful tool for analysis and design of healthy indoor environments.

Transient modelling of convective movements in a dwelling cell

Numerical modelling of convective air movements inside a heated room was built, using a coupling of a zonal model and integral analysis. The model describes the heat transfer between air and walls, between different air layers inside the room, between air in the room and cold air jet from ventilation air supply, and between air and heat emitter. Experiments were conducted in a testing chamber with floor heating or heating by a hot water radiator, with steps in hot water and ventilation flow rates. Validation results are satisfying.

An analysis of some subjective assessments for inddor air quality in five european countries

The study in 5 European countries has shown that indoor air quality was noted depending on the country first and on the perceived thermal comfort. Moderate humidity is perceived better while temperature in comfort zone less influence indoor air quality. When it is too hot or too humid, indoor air quality is badly perceived. CO2 levels have few relationship with perceived indoor air quality.

Ventilation, energy, and indoor air quality

This paper presents a complete overview of energy and indoor air quality issues related to ventilation. It comments ventilation in standards and in practice and gives information on the human response, health effects, air distribution, ventilation efficiency and different types of ventilation systems.

Building design for good indoor air quality

This paper discusses architectural design of buildings for a good indoor air quality, material selection, building design process, relationships between indoor and outdoor air quality. It shows that the roles of architects and engineers are complementary to obtain a good indoor air quality.

Experimental study of facial air supply method for the reduction of pollutant exposure

A thermal manikin with a simulated lung was placed in an air-conditioned office with fresh air supplied in close proximity to the facial area at flow rates from 0.1 to 2 l/s. CO2 concentration measurements allow to define the fresh air utilization efficiency and the pollutant exposuer reduction efficiency.

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