Study On Heat Transfer Performance And Application Of Underground Ventilation Corridor

The intensification of building energy has caused serious environmental pollution.The increase of energy consumption and the destruction of environment stimulate the soft spot of China’s economic development,so energy conservation and environmental protection are imperative.As a relatively mature building energy efficiency technology,the underground wind system has been widely applied both at home and abroad.With the further development of urban underground space,the underground ventilation corridor system arises at the historic moment.In order to explore the heat transfer performance of underground corridor system in hot summer and cold winter zone,the following studies are carried out in this paper.First,based on the thermophysical parameters and temperature characteristics of soil materials,we establish a soil temperature calculation model.Through theoretical calculation and experimental test,the temperature distribution of shallow rock and soil in the main city area of Chongqing is obtained,and the soil test values in summer and winter are compared with the calculated values.The accuracy of the soil temperature model is verified by the error within the allowable range.Secondly,based on the calculation model of soil temperature and outdoor meteorological parameters,the principle of unsteady heat and mass transfer in corridor air heat exchanger is analyzed,and the mathematical model of continuous operation and intermittent operation is established according to the differential equation of heat and humidity exchange between air and corridor.Then,taking an underground corridor system in Chongqing as the experimental object,the experimental test platform was designed and built to test the parameters of outdoor meteorological parameters,corridor wall surface air temperature and humidity,fan power consumption and other parameters,and from the corridor wall temperature,air supply state,fresh air temperature,moisture content and enthalpy value and so on.The results show that the average temperature drop of the new wind in summer and winter is 5.49 degrees,the average daily dehumidification is 5.49,the average daily dehumidification is 0.79g/kg,the ratio of energy efficiency is 8.65,the average temperature rise of the new wind is 3.18,the daily dehumidification is 0.72g/kg,the energy efficiency ratio is 4.95,and the energy saving effect is remarkable.Finally,a three-dimensional physical model is set up according to the actual corridor.The temperature distribution of the new wind in the corridor is simulated with the fluent simulation software,and the simulated values are compared with the measured values.The results show that the deviation of the simulated and measured values is 18% under the working condition in summer and the deviation of the simulated and measured values under the working condition of the winter is 19%.The result is reasonable.Based on the calculation and simulation analysis of the influencing factors of the heat transfer performance of the corridor system,the economic and reasonable corridor parameters are determined to facilitate the popularization and application of the corridor system.To sum up,this paper uses three methods of theoretical analysis,experimental test and simulation calculation to make qualitative and quantitative analysis of heat transfer effectiveness of underground ventilation corridor system in summer and winter.The research results can provide theoretical support for the application of underground corridor system in hot summer and cold winter areas.