SUMMARY
The article is devoted analytic evaluation of energy efficiency as high groundwater intermediate movable carrier phase in the presence of heterogeneity.Groundwater significantly affect the thermal conditions of the geological environment as carry on only the substance but also diffusion and convective heat.Evaluation of the energetic efficiency of groundwater as a mobile heat-transfer agent should be performed with consideration of the phase non-uniformity of the geological environment, i.e. the presence of liquid and gas components. Fluid (in this case, groundwater) significantly affects the thermal regime. When the water-bearing horizons are being filtrated, the ground water transfers not only substances dissolved in it, but also transfers heat energy. As with the migration of substances, the transfer runs in a convectional and diffusive way.Considering groundwater filtration area reduces heating medium in the presence of high-temperature sources (underground gasification and combustion of coal deposits, industrial thermal pollution). So it reduces speed and cooling medium for removing high-temperature source.Further refinement of paintings thermal state of the geological environment in the account of the possible phase transitions groundwater (so-called "Stephen’s task").To solve it in the presence of thermal groundwater (evaporation-condensation) proposed solution, which is similar to known solutions "solidification - melting." It is based on the account of heat loss in the crystallization zone, according to the state diagram solution or melt.The results of the calculation indicate the change in the heat field character of the generator over time. The areas of increase in the curve`s slope correspond to the transition zone of condensation. At the upper boundary of the phase conversion area, we see the first area of rapid temperature fall. The diameter of the gas zone does not exceed five meters (on average 3 - 4 m).Taking into consideration phase conversions and the transition zone improves the accuracy of thermal image of the object. The temperature regime, calculated separately for the water vapor, binary fluid and water, with the resultant curve gives an overview of the deviation of results obtained using standard methods of calculation from those obtained by the proposed methodsThe obtained results of environmental temperature change resulting from the operation of an underground gas-generator, which are based upon a calculation using familiar equations of heat-conductivity, coincide with the data obtained from the locality and may be used for the calculation of heat regimes of underground burning.