Theoretical And Experimental Research Of A New Type Automatic Wind Catcher And Ventilation System

Natural ventilation as a passive method of ventilation to save energy and improve indoor air quality has become increasingly significant advantages.Most buildings achieve natural ventilation by opening the doors and windows,and this is one of the most simple and effective means of natural ventilation.There are many specific factors limit the opening of the doors and windows for natural ventilation. When the dominant wind direction and the door are parallel,it's not conducive to realize natural ventilation.The controllability of the natural ventilation is poor through the doors and windows and easily lead to the heating and air-conditioning load increase in the room.How to achieve natural ventilation in the conditions above? The author has given full consideration to the adoption of wind pressure and hot pressure for natural ventilation and designs a new type of automatic wind catcher and ventilation system which can make the air inlet always on the windward side and the air outlet just at the leeward side;The positive pressure on the windward side can introduce the fresh air into the room,and the negative pressure on the leeward side can exclude the dirty air out of the room.It can greatly increase the indoor thermal comfort without consume energy.First,the mechanical properties of the wind catcher have been studied though the theoretical calculations and experimental methods.A wind catcher which can start-up with low wind speed has been designed though calculation according torque balance principle.The reliable opening wind tunnel test-bed has been set up which can get stability and homogeneous wind environment.The main factors including wind speed v(m/s) and initial positionθ(°) which affect the mechanical properties of the wind catcher have been studied.The results show that:①The start-up wind speed is 0.5m/s, and when the outdoor wind speed rises up to 1.5 m/s or higher,the device can track any point of the dominant wind direction.②The average reaction time is about 10 seconds.Second,the flow characteristics of the wind catcher have been studied though numerical simulation and experimental study.The wind catcher 3d calculation model has been set up and the flow field distribution in and around the wind catcher is also been understand.The research of the resistance characteristic which cause by the especial structure of the wind catcher give a good foundation for the further study of the wind catcher structure.The air flow rate performance of the wind catcher has been researched though the comparison of the numerical simulation and experiment.The results show that the wind speed and air flow rate of the section inlet and outlet increase with the outside wind speed linearly,the error between the simulation and experimental result is about 30%while the error of outlet2 air flow rate is very large, the main reason may be the calculation mode,error of experiment instrument,reading error and the condition of the experimental table.Third,this paper has given a comprehensive investigation of the wind environment in Beijing,at the same time test the wind environment of the single building in Beijing through wind anemoscope.The assessment system of the potential for the wind catcher applied in Beijing has been established.It provides a preliminary basis for the practical application of the wind catcher.Finally,the wind catcher and ventilation system has been applied to the monomer building.The performance of the wind catcher applied in Beijing has been studied though the theoretical of natural ventilation including wind pressure and hot pressure. The interaction between the wind pressure and hot pressure has been researched though the data of a typical winter wind day,and the air flow rate has also been tested. The specific conditions have been proposed for the application of the wind catcher in of Beijing winter.The research of the automatic wind catcher and ventilation system provides a new way of thinking and methods for the design of the building natural ventilation.