PERFORMANCE OF THERMOACTIVE MICROPILE AS LOW ENTHALPY GEOTHERMAL HEAT EXCHANGER IN DIFFERENT SEASONS

Abstract

The aim of this article is to show the results obtained from the use of a deep foundation micropile as a shallow geothermal exchanger, so that the micropile has a double functionality: on the one hand to support and transmit the building load to deeper stratus and, on the other hand, to exchange the soil temperature for heating the building through a ground source heat pump. In order to typify how the micropile performance as a geothermal exchanger is, we carried out several thermal response tests (TRT) in a micropile we made with this research purpose, that implements a reinforcing threaded steel bar designed for geothermal use. The micropile is located in a warehouse in the industrial area “La Planeta”, in Mancha Real (Jaén) This work has as purpose both to get to know the capacity of this micropile to exchange the ground heat and to typify its performance in a shallow geothermal heating system. To reach the first goal, micropile thermal resistance (Rb) is been calculated with the experimental data obtained from the thermal response tests. Meanwhile, for achieving the second objective, we made a range of heat insertion trials simulating the ground source heat pump performance in a building. This way, we determined how the soil temperature influences the heat exchange and the specific heat extraction power (W/m) we can get without thermally overloading the foundation. This value indicates the percentage of the building heating and cooling demand that can be covered by this geothermal system. Keywords: geothermal energy, energy efficiency, thermoactive foundation, self drilling micropile, geothermal heat pump