ESDA2008-59591 HEAT TRANSFER AND TEMPERATURE DISTRIBUTION OUTSIDE THE BOREHOLE

ABSTRACT In this paper a theoretical analysis of the non-stationary distribution of temperature outside a borehole in the ground is presented. The ground, surrounding the cylinder, is the source to heat or cool the medium flowing inside the cylinder. Direction of temperature distribution in the ground depends on the circumstance if the cylinder is responsible for heating or cooling. The discussion will concern the effect of an accumulation of heat in time by the deposit ( ground) and the distance from the borehole to the place where there is no heat exchange, as well as the influence of temperature distribution on cooling or heating effects. An analytical model was designed to determine a profile of temperature in the ground and the Nusselt number in the borehole dependents on both the time and the outward radius. An attempt is made to define the radius of the thermal influence of the