Natural Ventilation And Its Potential Evaluation Of Dwellings In Southern Anhui

Natural ventilation is beneficial to indoor thermal comfort and air quality.Evaluation of natural ventilation potential is an important part of buildings design of natural ventilation,which is very important for the building to use natural ventilation efficiently.This paper studies natural ventilation and its potential evaluation of dwellings in southern Anhui.Through investigation,measurement and theoretical analysis,the research on natural ventilation construction technology of Wannan dwellings is carried out.It uses CFD software to simulate natural ventilation performance of Wannan dwellings under wind pressure and thermal pressure.Natural ventilation potential evaluation model constructed is apply to assessment application potential and energy saving potential of natural ventilation of dwellings in southern Anhui.And natural ventilation of dwellings is optimized according to the research conclusions.The comfortable temperature range of Wannan dwellings under natural ventilation conditions is 10.7-30.9?and the humidity is 20%-90%.The ventilation strategy of dwellings in southern Anhui is night ventilation in summer,natural ventilation inhibited in winter,sufficient ventilation in spring and autumn and appropriate reduction of night ventilation.Ventilation time of the four seasons can be extended in terms of humidity.The patio plays a role in the ventilation system of Wannan dwellings.Under wind pressure,patio has a weakening effect on indoor ventilation and inhibiting cross ventilation of hall,but it has a certain uniform effect on wind speed flow field of hall.Under thermal pressure,the airflow direction of Wannan dwellings in daytime is opposite to that at night,and the thermal pressure intensity during the daytime is greater than that of nighttime.The patio enhances the hall ventilation under thermal pressure,and the air change per hour from 2.49 h^-1 to4.62 h^-1.Average air change per hour difference hours?AHDH?and the effectiveness of natural ventilation???are the evaluation indexes of natural ventilation potential for improving air quality and thermal comfort respectively.AHDH of Wannan dwellings under all doors closed is 2.8-4.4,and the dwellings infiltration ventilation is strong,which has great natural ventilation potential for improving air quality.The internal heat source is 200 W.When the air change per hour increases from 0.5 h^-1 to20 h^-1,?of spring,summer,autumn and winter changes from 56.9%,3.5%,67.9%,88.2%to 81.2%,81.8%,72.8%,18.6%respectively.That is to say,increasing the air change per hour can significantly increase natural ventilation potential of improving thermal comfort of dwellings in the summer and transition seasons,but reduces ventilation potential of dwellings in winter.From the perspective of improving thermal comfort,natural ventilation in summer and transitional seasons of dwelings should be strengthened,and natural ventilation in winter should be weakened.Hot temperature hours?HTH?is the evaluation index of natural ventilation energy saving potential.When there is strategic ventilation,HTH of the Wannan dwellings is 32193?·h in summer,and the natural ventilation has the greatest energy saving potential.In summer,dwellings should be ventilated strategically and ventilated from 20:00 to 6:00 at night.Renovation of old dwellings,the patio was transformed into open-close type.The design of the new dwellings,the building layout is facing south,the patio should be retained,and high airtight doors and windows and control strategies are used to regulate natural ventilation.