The air leakages can have a large impact on heating needs and thermal comfort in industrial buildings. This is sometimes poorly taken into account, both due to the lack of theoretical approach and knowledge of air tightness.

The design of natural, including passive, ventilation systems assumes one of two genericforms: the nasty design problem where the designer seeks to size ventilation openings givenclimatic conditions and thermal comfort criteria or the nice design problem where the designerseeks to size ventilation openings given climatic conditions, indoor temperature distributions,and specified airflow rates - presumably determined from separate thermal or air qualityconsiderations.

The air distribution effects of floor mounted swirl diffusers are investigated and described inthis paper. Results are based on a case study of an office typical of those in urban commercialenvironments. The effects of the swirl applied to the supply air as well as temperaturedifferentials between supply and room air are explored. The investigation is restricted tosituations where cooling is required.The results of the work, which is undertaken by way of CFD analysis, are presented in termsof appropriate ventilation effectiveness parameters.

When designing a new, or retrofitting an existing building it is desirable to minimise theheatinglcooling load, total energy use and emissions from combustion. Solutions toaccomplish this has to be held up against investment costs, maintenance costs,longevity and of course indoor climate (among other things). Optimisation betweenthese different and often competing criteria is complex, and involves a lot ofparameters.

Infiltration has traditionally been assumed to affect the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Results from detailed computational fluid dynamics simulations of five wall geometries over a range of infiltration rates show that heat transfer between the infiltrating air and walls can be substantial, reducing the impact of infiltration.

Simulations have been performed to investigate the performance of intelligent algorithms for control of indoor air quality through natural ventilation strategies whilst simultaneously meeting the requirements of thermal and visual comfort. The proposed control algorithms are founded on the knowledge base of the building physics and support the control of natural ventilation through control of the window opening, whilst simultaneously controlling the lighting, heating and cooling systems of the building.

Similar to supply air jets in mixing ventilation this paper describes a comprehensive flow model for displacement ventilation derived from the integrated Navier-Stokes differential equations for boundary layers. A new test method for low velocity diffusers in displacement ventilation is developed based on this new flow model. Contrary to jet flow, it is shown that the only independent variable in the new model is the buoyancy flux.

Includes sections on modelling and control algorithms, equipment and envelope characteristics, ventilation performance and building airtightness, ventilation strategies and pollutant transport, NATVENT - overcoming technical barriers, and cooling and indoor air quality in commercial and public buildings.

The purpose of the work described in this paper is to develop a mathematical model of downdraft exhaust hoods in order that ways of improving these hoods efficiency can be examined. In this initial study the model developed is twodimensional. The flow has been assumed to be ideal and the complex potential considered. By use of conformal mappings the airflow in the vicinity of a bench, which is extracting air and also has air being blown down from above, is modelled. Various ratios of extraction to downdraft are considered in order to investigate the most efficient method of operation.

The air leakages can have a large impact on heating needs and thermal comfort in industrial buildings. This is sometimes poorly taken into account, both due to the lack of theoretical approach and knowledge of air tightness.