Natural and hybrid ventilation concepts are today the mean items of some international researchers about the behaviour in the innovative buildings. In fact they are utilised to contribute to the thermal comfort and the indoor air quality control. Besides there are other advantages as the low use of the energy and the reduction of noise levels. In the last years the study of the hybrid ventilation systems in the office and in the school buildings has in progress as the principal aim of Annex 35, organised by IEA. The present work wants to value the fluid dynamic phenomena organised by IEA.

Airflow pattern in an indoor sports hall of 17,325 m3 located in the sports complex of City University of Hong Kong has been investigated by computational fluid dynamics technique. The turbulence flow was taken into account by using Renormalisation Group method (RNG) k-e model. The objectives of this study are to obtain a preliminary understanding of the airflow pattern and evaluate the badminton 'playing zone' within which there should be no disturbance to the badminton shuttle behaviour.

A mathematical model has been set up for the multizone structure region in this paper. By the way of numerical simulation, the analyses are conducted of air flow and aerosol particle travel under the mechanised ventilation condition. The results of such analyses provide useful data for ventilation system design and the indoor air quality control.

By using the technique of turbulent large eddy simulation (LES) and finite element method (FEM) of computational fluid dynamics (CFD), the three dimensional flow fields in vector flow clean-room under empty state and static state condition were predicted. The partly expanded Taylor-Galerkin discretization scheme cooperated with implicit stream-upwind diffusion effect was used to deduce the finite element formulation of basic equations through Gauss filtering. The subgrid model of vortex viscosity was adopted in the numerical simulation.

In large buildings, pollutants may be emitted locally and discontinuously what can result in time dependent heterogeneous pollutant concentration fields. Efficient ventilation solutions should provide the right amount of fresh air at the right place so as to minimise energy cost and discomfort. In this paper, a new ventilation strategy is developed. It is divided in several phases. First, pollution sources are identified with a minimisation technique and then the time dependent pollutant concentration is predicted.

In modern buildings, smoke control systems are integrated into the air supply systems. It is possible that the design of the smoke control system will dominate the design process of the air supply system. Smoke reservoir size is one of the design parameters for the smoke control system. The reservoir size has been limited to 2000-3000 m2 in both Hong Kong and UK. However, this study revealed that the smoke reservoir size should be considered in connection with the slab ceiling height of the smoke zone. The higher the slab ceiling, the larger the smoke reservoir could be.

Based on the literature and our long-term investigations on indoor environment, the heat source patterns (distribution, location, size, etc) have a predominant effect on temperature efficiency as well as ventilation effectiveness. Although the heat sources of ventilated rooms are various and complicated in engineering practices, some typical characteristics still exist in common.

A large part of the housing stock in the Netherlands is ventilated badly. Exhaust systems do not work according to building standards. Bad design, bad maintenance and deterioration give a reduction in exhaust volumes of more than 50 %. Home owners and tenants compensate with extra cross-ventilation, but often the results is poor. The National Union of Tenants and the Research Institute OTB cooperated in the design of a quality assessment tool, to evaluate the provisions for ventilation in housing. The tool is a checklist for the quality of ventilation services in the house.

Ventilation effectiveness is an important means to describe and evaluate the performance of a ventilation system. In terms of ventilation tasks, this paper presents a unified physical model for the ventilation efficiency scales based on conservation principles to which a ventilation system should conform. Transport equations for the local mean age of air and contaminant are respectively obtained, which can be integrated solved by the CFD program. To validate the proposed model and CFD simulation of the ventilation efficiency, a 2-D laminar ventilation flow is analysed.

On the bases of the definitions of air conditioning period, dehumidifying period and heating period, this paper puts forward to the exchanging conditions and psychometric process of ventilation system in residences. In order to improve on thermal environment quality and indoor air quality (IAQ), new strategies must be found to control both temperature and humidity of ventilation system.