SARS Transport On Basis Of Natural Ventilation And Natural Ventilation Theory Research

The two topics on sustainable development of building are energy-saving and indoor air quality. Natural ventilation is an important technology to make building develope sustainably. However, energy consumption in buildings can be reduced and at the same time indoor air quailty can be improved by the means of natural ventilation only when natural ventilation is controlled well. The investigation of the nature of natural ventilation and pollutant transport in naturally ventilated building is very significant for the design and control of natural ventilation systems, the better use of natural ventilation technology and the control of pollutant transport.The paper first reviewed the state of study on the transmission routes of SARS, natural ventilation theory and methods. Then the Multi-zone Infiltration and eXfiltration Model (MIX) is presented.Many opinions on SARS transmission routes in the SARS super-spreading event in Amoy Gardens in Hong Kong exist, one of which is airborne transmission. The SARS transport, the dynamic variation of SARS virus concentration and airflow in Block E in Amoy Garden which is very difficult to predict are simulated by MIX after it is developed reasonably and originally. Compared MIX results with the spacial distribution of the confirmed cases of SARS in Block E, the corresponding relation between them is found. So it can be concluded that the airborne transmission routes is an important one of the major SARS outbreak in Amoy Gardens and the wind and thermal plume resulted in the air flow between flats in Block E.The paper perfected and extended the predicted model of air flow rates in natural ventilation driven by both wind and thermal force in four-opening buildings, which has been introduced in the British Standard (BS5925). Four flow modes, that is, strong wind-dominated flows.weak wind-dominated flows, strong buoyancy-dominated flows, weak buoyancy-dominated flows, exist in this problem. With the relative change of wind and thermal force, strong wind-dominated flows and strong buoyancy-dominated flows will switch each other, in which weak wind-dominated flows or weak buoyancy-dominated flows will be their transition mode. Coupled the energy-conservation equation with the calculation formula of natural ventilation rates, the new model on natural ventilation rates for heat-source-strength-given problem and dynamic control equation arc obtained by introducing some characteristic parameters.At last, the stability of fixed points on air flow rates and the effect of initial indoor air temperature on dynamic process of natural ventilation are analysed by means of non-linear dynamics method.