Performance Study Of Composite Enhanced Ventilation System Of Tunnel Ventilation Precooled Solar Ventilation Tower

At present,the problem of energy consumption in large space is very prominent,among which the proportion of energy consumption of air conditioning is the largest,and the energy consumption of air conditioning comes from cold source and the power equipment that conveys air.Therefore,in order to reduce the energy consumption of air conditioning,it is necessary to solve the problem of these two aspects of energy consumption.On the one hand,the soil temperature below 3m in most areas remains constant at about 18?,so the tunnel system can be considered as a cold source for large space.On the other hand,the"chimney effect"of solar energy can use hot pressure to drive gas flow and act as power equipment in air conditioning.Therefore,taking a theater in Hainan as an example,this paper puts forward an integrated system of tunnel ventilation precooling and solar ventilation tower for large space buildings,tunnel ventilation system is used as a natural cold source to cool the outdoor air.After cooling,the air first enters the static pressure box,converts the dynamic pressure into the static pressure,and then adopts the way of down-air supply.The temperature and velocity field of the working area are more uniform by conveying the tuyere under the seat to the interior of the building.The system is driven by the strong buoyancy generated by the thermal compression enhanced by the solar ventilation tower,which enables the theater to eliminate the residual heat in the theatre by natural ventilation.In this paper,fluent software is used to simulate and analyze the integrated system of tunnel ventilation precooling and solar ventilation tower in theatre by numerical simulation.The main factors such as tunnel length,single and double tunnels,air intake mode of static pressure box,air outlet size,solar ventilation tower size and optimization are studied.The conclusions are as follows:(1)For the single tunnel composite system,when the length of the local tunnel is increased from 80m to 140m,on the one hand,the air supply temperature is reduced by2.5?,which improves the comfort of the working area,but on the other hand,the ventilation volume is reduced by 17.32%.The same is true of the double tunnel composite system.In the range of study,the optimum length of single and double tunnels is 140m and120m,respectively.(2)The comparison of single and double tunnels shows that under the same ventilation rate,the gas dynamic pressure can be reduced and the uniformity of air supply can be improved by the double tunnel composite system.(3)According to the simulation and comparison of the two ways of the inlet air left and the lower inlet of the static pressure box,it is found that although the ventilation in the downwind mode is larger than that in the left wind under the condition of the same tunnel length,the vertical reserved attenuation space is smaller than that in the horizontal direction.Therefore,the distribution of temperature field is more uneven when the air is fed down.(4)When the size of the grid type tuyere increases from 0.05m×22m to 0.20m×22m,the difference of the front and rear exhaust temperature increases from 0.42?to 1.67?.It can be seen that increasing the size of the tuyere is unfavorable to the uniformity of the temperature field in the working area.(5)The simulation results show that:first,when the solar radiation intensity increases from 200w/m~2 to 800w/m~2,the ventilation capacity of the composite system increases24.05%,and the ventilation performance increases with the increase of solar radiation.Second,increasing the height of the solar ventilation tower can improve the ventilation performance of the system(when the solar ventilation tower increases from 10 m to 25 m,the ventilation capacity of the composite system increases by 63.83%);Thirdly,in the range of study,the increase of the width of solar ventilation tower can effectively improve the ventilation performance of the composite system(when the width varies from 0.5 m to 1.25m,the ventilation volume of the composite system increases by 56.13%);Finally,the veneer can rotate freely by improving the structure of solar ventilation tower.In the range of study(0.2?~0.8?),the larger the rotation angle,the stronger the ventilation ability of composite system.Thus,the rotation angle can be adjusted according to the solar radiation intensity,making the system more flexible and climatic adaptability.