Significant limitations in applying computational fluid dynamics (CFD) to predict room air distribution: guidelines for beginners.

Computational Fluid Dynamics (CFD) has been used to predict the indoor environment airflow and overall ventilation effectiveness of natural or mechanical air distribution systems. This paper highlights some applications and criticism work made on CFD in order to establish an understanding of the limitations of CFD in predicting room airflow. It is concluded that though CFD is a powerful tool for simulation, the software complexities, computational power and the level of expertise that CFD codes require shape the greatest challenges to beginners in this field.

Duct leakage in European buildings: status and perspectives.

A large number of modem European buildings are equipped with ducted air distribution systems. To investigate the implications of duct leakage, a field study was performed on 42 duct systems in Belgium and France. The measurement data confirm the findings of the few earlier experimental investigations on these matters in Europe. In our sample, the leakage rate appears to be typically three times greater than the maximum permitted leakage adopted in EUROVENT 2/2 (Class A).

Air distribution and air quality in a large open space.

A case study of the ventilation characteristics of office accommodation forming part of a recently refurbished building is presented. A mechanical system has been installed to ventilate and cool two floors that are interconnected by a series of atria, with a novel application of displacement ventilation applied where there is a very low ceiling height. The air distribution and air quality within the space have been studied by the application of computational fluid dynamics (cFD) to allow the computation of air change effectiveness in terms of local mean age.

Improving ductwork: a time for tighter air distribution systems.

A large number of modern European buildings are equipped with ducted air distribution systems. Because they represent a key parameter for achieving a good indoor climate, increased attention has been given to their performance during the past fifty years. One aspect that is particularly developed in this handbook concerns the airtightness of the ductwork, which has been identified as a major source of inadequate functioning and energy wastage of HVAC systems. The investigations were carried out within the framework of the DUCT project (1997-1998).

 

 

Ventilation in 2 or 3 unit multifamily buildings before and after weatherization.

This study investigates the fresh air distribution in 2 or 3-unit multifamily buildings before and after weatherization and evaluates the effectiveness of exhaust-only ventilation in providing the minimum recommended fresh air flows to dwellings in such buildings. Lowrise multifamily buildings often have no mechanical ventilation system and rely on the air leakage through the exterior envelope to provide outdoor air to occupants.

Energy efficient room air distribution.

An environmental chamber has been used to compare the effectiveness of mixing and displacement ventilation in terms of heat and contaminant removal. Results are presented for CFD simulations of the air movement in the chamber and for measurements using a heated mannequin with displacement ventilation. The CFD simulations and the measurements suggest that displacement ventilation is more energy efficient than a mixing system.

Individual air distribution control panel on partition panel at personal task area.

A general trend in intelligent buildings is the decentralization of environmental controlsystems. Decentralized environmental control systems have many advantages over centralizedsystems. In order to filly utilize a decentralized control system, the control zone should becompletely individualized so that one occupant can feel free to adjust the air volume andtemperature without being concerned about affecting the comfort of other occupants. Afurniture integrated air distribution control system can provide highly individualizedenvironmental control.

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