The paper is concerned with mathematical modeling of heat and mass transfer in subsurface geothermal systems. Heat exchanger is driven as a vertical channel in an impermeable rock massive. The temperature of rock is driven in accord with a usual thermal conductance equation on a cylinder coordinates basis. The boundary conditions between the rock and heat exchanger are given by the equality of a thermal flow.

The drainless basins are widespread in the zones of steppes, semi-deserts and deserts over a vast area, from Transbaikalia in the east to the Black Sea in the west. Sometimes they reach considerable sizes and great depth. Morphology, geological structure of the basins, their origin are very diverse, but all of them are united by one common feature — absence of runoff. The feeding conditions of lakes located at the bottom of many basins are also diverse. The main sources of feeding of these lakes include waters of: 1) surface runoff, including carved waters; 2) large reservoirs; 3) groundwater; 4) artesian waters.