Design And Optimization Of Natural Ventilation System For Double Skin Facade In High-Rise Building

Compared with single glazing curtain wall,the insulation performance of Double skin fa?ade is good in winter;Double skin fa?ade can also play a very good heat insulation in summer by setting up a reasonable inlet and outlet and shade measurers;double skin fa?ade can effectively use the natural ventilation in the transition season,thus saving air conditioning ventilation energy consumption.Due to the special structure of the Double skin fa?ade,the flow and heat transfer process are complex,especially when using natural ventilation,the indoor thermal environment depends not only on the local outdoor weather conditions,but also by the micro-climate around the building,it is necessary to consider the common role of hot pressure and air pressure.In this paper,according to the architectural structure and climate characteristics,design the structure of double skin fa?ade ventilation system to meet the requirements of natural ventilation in the transition season.In order to reduce the energy consumption of the air conditioning system,the double skin fa?ade adopts a series of energy saving measures such as hollow LOW-E glass,heat-cut profiles and adjustable sunshades,and set the natural ventilation holes in the curtain wall to improve the energy efficiency of the double skin fa?ade.Then,calculate the natural ventilation of the building with Energyplus to analysis the indoor temperature of Chengdu in April.From the results of natural ventilation calculation can prove :(1)using natural ventilation in the building’s double skin fa?ade is feasible;(2)by increasing the width of the joints can improve the indoor natural ventilation effect,but in the leeward side indoor thermal comfort is poor,the natural ventilation structure must be optimized,or increasing mechanical ventilation.Finally,the three-dimensional numerical calculation method is used to calculate the indoor air flow.When the width of the seam is 81 mm and the outdoor wind speed is 1.1m / s and 1.5m / s respectively,the indoor thermal environment calculation results show that:(1)the upper and lower room temperature difference is larger;(2)The temperature of the upwind room is significantly higher than the other rooms;(3)When the width of the seam is 81 mm,the indoor temperature will decrease obviously with the increase of outdoor wind speed.However,the outdoor wind speed in Chengdu is low in the transitional season.Therefore,increasing the width of the seam is necessary so that can increasing the air intake to improve the indoor wind speed then Improve the indoor thermal environment.Based on the above calculation results,the shape of the curtain wall is modified,and the original straight strip is changed into a horn shape,and the width of the slit is expanded from the original 86 mm to 125 mm.The outdoor wind speed were 1.1m / s and 1.5m / s,respectively,when the indoor thermal environment were calculated.Through the analysis of the results,it was found that the width of 125 mm strip in the transition season of Chengdu,the outdoor temperature of 20.5 ℃ can meet the comfort requirements.