Study Of Influence Of Shading Louvers On Wind Environment Of A Multi-Storey Building With Natural Ventilation

With the increasingly serious problems of environment and energy,energy conservation and emission reduction has become an important measure to maintain China’s low-carbon economy and sustainable development.Building energy consumption accounts for a large proportion of the total energy consumption,so building energy conservation plays an important role in promoting energy conservation and emission reduction,which has attracted great attention.In built environment,shading devices are usually used to reduce heat gain from solar radiation and the energy consumption of buildings.Meanwhile,shading devices have a impact on natural ventilation in the transitional season,which can not only change indoor light and heat environment,but also change wind environment and air quality.In this paper,the wind environment of a multi-storey building with shading louvers was investigated.The influence of shading louvers on the indoor and outdoor wind environment was analyzed by the method of computational fluid dynamics.The main contents and conclusions are as follows:(1)Numerical simulation is carried out for the outflow field of the shaded building,and the data in the previous study are used to verify the simulation results and sensitivity analysis.The influence of computational domain,grid resolution,turbulence model,geometric scale and near-wall treatment on the distribution of air velocity and wind pressure coefficient are evaluated.The results show that the largest deviation occurs between different turbulence models.And the accuracy of k-ε model is the highest.(2)The distribution of wind pressure coefficient on different positions of multi-storey building surface under different shaded conditions is investigated.The results show that when the approaching wind is perpendicular to the shaded facade,the average values of wind pressure coefficient in shaded condition are mostly lower than those in the non-shaded condition.The highest reduction of average value is 0.54,which occurs in the shaded condition with 75°rotation angle.The highest increment of average value is 0.19,which occurs in the shaded condition of 15° rotation angle.(3)The coupled indoor and outdoor airflow model is carried out to evaluate ventilation capacity in the shaded building.The deviations between coupled airflow model and simplified engineering model are calculated to evaluate the accuracy of simplified model based on the orifice equation.Compared with the non-shaded condition,the results show that the ventilation rate is mostly reduced in cross ventilation,while that is mostly increased in single-sided ventilation.In cross ventilation,the highest reduction of ventilation rate occurs in the shaded case with 75° rotation angle and 0° wind direction,where the average ventilation rate decreases by 45%.Both two ventilation modes meet the requirements of the relevant standard.(4)The age of air and the particle deposition velocity on the interior wall are studied in the coupled airflow field of the shaded building.The results of deposition velocity show that the average deposition velocity in shaded condition is mostly lower than that in non-shaded condition.Compared with the non-shaded condition,the results of age of air show that the highest increment of age of air for the shaded building is over 100s in cross ventilation,while that is over 1000s in single-sided ventilation.The presence of shading louvers can significantly increase the air freshness in some regions,but the particle deposition velocity will mostly be reduced.