Short-circuiting of ventilation air reduces significantly the efficiency of ventilation in diluting and removing contaminants and excess heat. Therefore the prevention of short-circuiting is very significant to consider at the design stage of air distribution in ventilated rooms. The paper reports on results obtained experimentally from both full-scale and small-scale laboratory tests. Air distribution was quantified by measuring the local mean age of air and the air-exchange efficiency using a trager gas technique.
This paper gives an outline of the work that has been carried out in developing a positive ventilation chiller. The demand for air cleaning equipment in public areas and work places (especially where smoking is permitted) had previously prompted the development of a highly innovative ventilator, featuring a combination of ventilation, recirculation and filtration of air. A refrigeration system was successfully retrofitted into the ventilation unit. The chiller is aimed at improving the working and living environment where modem air conditioners are beyond affordability.
Ventilation design has a long history in China. The ancient pioneers used engineering skills to change the indoor environment. In this review, basic natural ventilation design ideas are introduced from both a historical and modern viewpoint. Attention is paid to new natural ventilation system developments, such as the design and testing of natural ventilation inlets and outlets for the stack and solar chimneys. Theoretical aspects of ventilation design are also considered. Today, the use of mechanical ventilation systems in China is growing for both domestic and non-domestic buildings.
The feasibility of designing ventilation routes in the house with passive ventilation system is investigated using the numerical experiments and the measurements on its ventilation rates and indoor air quality. As a result, the ventilation design using the used-air in the rooms on the second floor is proved to be one of the simplest ways to keep good indoor air quality. And the required airtight level of the house with the ventilation design is lower than that with the general ventilation design where the air is supplied to every room.
In designing thermal and ventilation systems in buildings, an examining process of exchange between the designers and analysts is needed. This study aims to expand the simulation system of thermal and ventilation into an automated process for the design of optimum thermal and ventilative conditions, based on the expertise of analysts, the analysis of the thermal environment and the modification of the design, by automating these functions.
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