A procedure to verify, validate and report CFD analyses in indoor environment applications has been developed. The process on how to use this procedure is explained through the example of CFD modeling of an office with mechanical displacement ventilation.
Ventilation airflow rates and internal air distribution were measured in four poultry slaughter plants (250 to 775 workers), equipped with negative pressure ventilation systems (exhaust flow rate from 7.1 to 27.4 m3/s - no air intakes - supply air entering through various openings). Results lead the authors to recommend the installation of diffusers for makeup air supply, changes in the organisation of rooms to avoid contamination of one by the other and regular maintenance and cleaning of ventilation components.
An audit of 20 hospital operating rooms was operated in Grece in order to collect information about the HVAC installations and the indoor physical parameters. Data were also collected from 560 medical personnel through a questionnaire about the assessment of the indoor conditions.
Tests have been performed on several ceiling air diffusers supplied with low air temperatures (6 to 16°C - 90% humidity) to study water vapour condensation on diffusers surface. Results show that a supply air temperature of 11°C avoids most of condensatio
The risk of contaminant deposition (10 microns particles) on an operating room surgical site is evaluated for different ventilation systems - conventional, laminar, non-aspirating, displacement -, using airflow modeling and particle tracking methodologies. Results show that laminar flows are the most appropriate to avoid particles deposition.
The paper gives an explanation of the phenomenon of attachment of a cold air jet to a ceiling, based on a theoretical analysis. A formula to calculate the distance between the blowing slot and the point where the cold air jet will separate from ceiling is given. The results of calculations using this formula show good agreement with experimental data.
The market evolution of domestic exhaust air heat pumps since 1979 in Sweden is described. Some information is also given about the German market. Technologies of different exhaust air heat pumps systems are shown and results of several monitoring projects in Sweden are summarized : they show for houses built in the 1980's an electricity consumption of 90 to 130 kWh/m2/year (including domestic hot water and household electricity), depending on the thermal characteristics of the building envelope. The energy savings thanks to the exhaust air heat pump are about 30%.
Flow and heat transfer calculations have been operated in a typical office room equipped with a displacement ventilation and a chilled ceiling system. Results show quasi-periodic flow when the values of internal thermal loads are high. They also show lateral oscillations of the plumes above heat sources which create after impact on the cold ceiling recirculating flows in the room.
Suggests that particularly for outdoor thermal comfort assessments in cold conditions, non-steady state models should be applied. This and other new aspects are to be considered in a new internationally standardised Universal Thermal Climate Index (UTCI), at present being developed by the International Society of Biometeorology. Psychological factors also need to be considered, such as diverging thermal expectations indoors and outdoors. States that as a consequence, different approaches are needed to assess indoor or outdoor thermal comfort.
Describes the thermal model available, both simple and complex and outlines capabilities and limitations. States that all of the models have limitations for use in standards, including the accuracy of the physical simulation and the accuracy of the inputs to the model. States that the biggest limitation is probably the accuracy with which comfort perceptions can be related to the physiological variables simulated in the thermal models.