The Tool Of Natural Ventilation Adided Design In Residential Buildings And Its Application

In the dual goal of reducing energy consumption and improving the indoor air quality,natural ventilation,as an ancient ecological technology,is regarded again in current society with the role of cooling,dehumidification,providing fresh air as well as meeting the people's request of approaching to nature.Accurate prediction of natural ventilation is the basis of its design and application.At present,qualitative analysis is mostly applied to research of natural ventilation at home,because of lacking corresponding mature and reliable tools.Firstly,summarizes the mechanism and calculation method of natural ventilation, through which we analyze that multi-zone network model is an effective means to study natural ventilation.At the same time,clarify the principles as well as physical and mathematical description of multi-ventilated network model and study numerical solution of nonlinear equations of the ventilation network system.Then,expatiates the process of how N-vAD(Natural ventilation Aided Design) come true by introduce its structure and main modules,on the base of "Multi-zone network model".Gives the original procedural codes for some difficult technic,such as the communication with CAD and MATLAB,the universal procedures for establishing the nonlinear equations of the ventilation network system.The discharge coefficient(Cd),reflecting resistance characteristics of opening,is a key parameter of natural ventilation.Presently,the general view that the traditional flow coefficient value:0.65 to 0.6 is no longer applicable to the large openings model of natural ventilation.On the basis of summing up the research status quo of Cd,the author analyzes the aperture rate and flow angle-θ's impact on Cd with the use of CFD method. It shows that the opening at the windward side is significantly affected by 0 and Recommended values suitable for application of Cd are provided,settled the base for optimizing the N-vAD.N-vAD is validated by the simulation results of CFD,which shows that,natural ventilation calculation software based on the model of multi-zone network can accurately reflect the distribution of wind pressure,errors in ventilation room are relatively reduced which meet the application requirements.Then,the author points that window screens should be taken into account to modify the flow rate for residential buildings.Finally,by two examples,analyses the influence of air flow rate and body's thermal comfort feeling on energy calculation of air-conditioning in the summer for naturally ventilated buildings,doing some exploration for the broad application of N-vAD.The work we have done provides a software platform and tool of quantitative calculation for the optimization of design and engineering application of natural ventilation,which has the practical engineering significance.