Numerical model for heat transfer between air and buried layer in buried tubes

Establishes a physical and mathematical model of earth-air heat exchangers (EAHE) with single layer buried tube and unidirectional flow. Integrates the two-dimensional unsteady heat conduction explicit numerical model for soil temperature and the one-dimensional convection-diffusion implicit numerical model for air temperature and moisture content. Adopts the finite volume method for spatial discretization and calculates the air parameters in the tube by the upwind scheme. Proposes a sequential algorithm for calculating air humidity, calculating air temperature, correcting air humidity and calculating soil temperature. The model is suitable for both shallow and deep buried systems. Verifies the accuracy of the model by the measured data of the deep buried tunnel.