Numerical Simulation Analysis Of Displacement Ventilation Inairport Terminal

With the development of modern architectural science and technology, as well as the improvement of human’s requirements, large-space buildings have become increasingly useful in recent years. Obviously, airport terminals are the most typical large-space buildings, whose main function is to accommodate passengers and equipment. HVAC systems are usually installed to maintain comfortable indoor environment for airport terminals, consequently consuming massive energy during the system operation. It is of great significance to analyze the measures of energy conservation for airport terminals, and discuss the issue of creating comfortable thermal environment.At present, layered nozzle outlets are most commonly adopted for airport terminals. Except for the low ventilation efficiency and energy utilization rate, people have to breathe the reflux zone air of poor quality. Under this circumstance, researchers have switched their attention to displacement ventilation and followed the example of foreign acts. Compared with layered nozzle outlets, displacement ventilation can significantly improve indoor air quality, reduce energy consumption and improve ventilation efficiency simultaneously.Accounting for the particularity of space areas and exterior envelopes of airport terminals, appropriate HVAC design indoor parameters are chosen. Taking the terminal airport in Shanghai as the research project, effective cooling load is calculated by both effective heat factor method and simulation method. Analysis of cooling load of departure hall is based on the UCSD module of Energy Plus, which is not applicable when heat transfer of the retaining structure dominates. Besides, according to the result of CFD simulation, the actual value of cooling load is approximately 85% of the effective heat factor method value. To provide reference advice in future application, design methods for large-space displacement ventilation are concluded.After the establishment of geometric model and numerical model of the airport terminal, thermodynamic stratification, temperature field and velocity field under different supply air stream forms are analyzed in detail using Fluent. Results indicate that position and size of the outlets have little effect on temperature field and velocity field, while air exhaust at the top can effectively reduce indoor overall air temperature. When cooling load and volume of supply air are constant, the indoor flow field tends to be uniform, and heat removal is enhanced with the increment of air supply area. Moreover, if the cooling load of air supply is fixed, indoor overall air temperature significantly decreases when air supply temperature and air supply volume are small, resulting in energy conservation for displacement ventilation system.Aiming at local high temperature regional phenomenon around glass wall, local cooling method is adopted to improve thermal environment. On the basis of the results above, temperature field and velocity field of departure hall in airport terminal are optimized, which improves energy conservation and maintains the comfortable indoor environment.