Full-scale laboratory measurements combined with numerical simulations were undertaken to evaluate CFD capability to predict the pesticide dispersion in a naturally ventilated building. CFD successfully reproduced the trends but overestimates the mixing inside the building.
This paper describes the precautions that have to be taken in design and installation of ventilation systems in order to reduce their noise. They concern fans, ducts and ductwork, air inlet and outlet, air diffusers, air handling unit.
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.
This work concerns turbulence levels in a practical operating theatre of a 1200 beds Egyptian modern teaching hospital. The turbulence characteristics were represented by a modified k - epsilon model. Then a series of experimental investigations were preformed in the operating room to investigate the flow and temperature patterns and to assess the validity of the numerical model to be used.
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.
This paper deals with experiments made to test the performance of a personalised ventilation system (PVS). 30 human subjects have participated to the experiment in an office with 6 work stations equipped with a PVS supplying outdoor air.The perception of air quality and the thermal sensation for each participant has been reportedduring their exposure to combinations of 3 levels of personalized air temperature, 4 airflow rates and 3 levels of room air temperature.
30 human subjects participated in a 3 h 45 min. experiment, that took place in an office with mixing ventilation and personalised ventilation systems (PVS).Each person could choose the position of the personal air terminal device, the direction of the air supplied and the flow rate (up to 15 l/s.person).The subjects were exposed to 4 following experimental conditions : PVS supplying outdoor air at 20C, then 23C ; PVS supplying re-circulated room air ; mixing ventilation, without PVS.Results allow to know how the PVS were used by participants (choice of position and flow rate).
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.
This work deals with the characterization of the thermal performance of a LHS (Local Heating System) tested on 18 persons (9 males and 9 females) working in a real free-running office with mean room temperatures varying from 16C to 18C. Local heating systems investigated consist in a combination of two radiant panels and a foot heater. During the measuring tests, the metabolic rate, the tympanic and local skin temperatures were monitored.
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.