English

One of the reasons for using displacement ventilation is that it may provide better indoor air quality in the occupied zone than conventional mixing ventilation. It is therefore important to understand the importance of the system on this aspect. A validated CFD model was employed to generate concentration distribution data for CO2, radon and moisture in a Hong Kong shop with displacement ventilation. Analysis found that the concentration distribution affected by factors such as the source type and location, its associated plume strength and human body convection, etc.

A research initiative, aimed at obtaining status-quo measurements of Indoor Air Quality (IAQ) and ventilation characteristics in air-conditioned office buildings in Singapore, has resulted in an extensive database, which details are presented in this paper. An integrated IAQ audit methodology developed during the course of the research will be presented and its application to nine buildings will be discussed in chemical, biological and particulate dimensions as well as the thermal comfort parameters.

The indoor environment is by far the most important environment from a health perspective. Allergies, airways infections, lung cancer etc. are associated with indoor air quality (IAQ) in developed countries and they are related to the use of energy for buildings. The main problems related to buildings, energy conservation and health in the developed world concern 'dampness' and inadequate ventilation. It is well established that if there is no 'building dampness' and if the ventilation is adequate then the risk of IAQ-related diseases is low.

Apart from Government's legislations and regulations, standards and guidelines, administration and publicity, ecological design [1-3] is a necessary approach to a clean environment. The fundamental rationale is to minimize the detrimental impact on our ecological environment. The study illustrates urban design and city planning are one of the "tools" and approaches to achieving the goal of a cleaner air quality, energy conservation and good, natural ventilation.

Recently the air quality has caused people's great attention, and the appraisal of the air quality has become a hot issue in the worldwide. This paper assets that the age-of-air should be an important index to evaluate the air quality. Since the architecture place becomes more and more complicate and diversity, the traditional searching method has a lot of limitations. With the development of computer technique, the superiority of computational fluid dynamics (CFD) method becomes more and more obvious, thus the CFD begins to be applied to the HVAC.

The paper proposes the definitions of the micro-climate zoned indoor and the controlling, it says apply the micro-climate zoned controlled can decline load and reduce the energy of the air-conditioning system. The paper proved the effectives measures of realizing the microclimate zoned controlling by applying airflow partition or displacement ventilation. The aim of this paper is qualitatively found a basal definition of microclimate controlling.

With the increasing number of private cars possessed by salaried people, there has been a change in the condition of ventilation for underground garage. In accordance with this new situation, and from the point of energy saving, this article specially points out an approach, which can determine and control the quantity of ventilation for underground garage.

As researches on air delivery to air-conditioning room are turning from static mode to dynamic mode, especially the natural airflow simulation plan is being put forward, these, in turn, require more thorough understanding and more effective evaluation method of various airflow turbulence patterns. On the basis of large amount of carefully controlled measurements of air velocities which are generated in air-conditioning room, outdoor and by local fan, a detailed calculation and analysis has been made in the light of the rapidly developing nonlinear science - chaotic theory.

This paper deals with the performance evaluation of three types of low-level ventilation systems: the wall displacement ventilation, the floor displacement ventilation and the impinging jet ventilation systems. The comparison between the performances of these three systems is based on air movement, comfort assessment, mean age of air and ventilation efficiency for contaminant removal. Data from measurements and CFD simulations are used for comparisons.

If the swirling airflow is formed in the room, the ventilation effectiveness in the room becomes better than by the other method, as the airflow pattern has the fixed direction and the stable airflow path is built up. To make swirl the room air, it is necessary to supply getting larger airflow rate toward outer zone from center. To supply such an airflow distribution simply is used the multi-openings square duct. The reason is that the supply airflow distribution of multi-openings duct has a tendency to increase toward the tip.