Abstract
The paper analyses the problems occurred at air conditioning in the underground railway. The causes of soil temperature increasing when operating the ventilation systems of underground structures were examined as well. The authors offer the model of calculation of a daily heat accumulation in the soil surrounding a subsurface air duct. The method of calculation of a specific heat flow on the surface of a similar duct for two types of soil typical for Moscow is presented. The model is based on the analytical solution of the problem of nonstationary heat conductivity in the soil at asymmetrical nature of outdoor air temperature change. The model allows calculating not only the heat exchange intensity on the surface of the air duct but also the change of an average temperature as well as an average heat content of soil layers adjacent to the air duct. These changes influence the temperature of the transient flow of supply air, and so, impact considerably the sanitary conditions in the underground railway.