Geothermal energy in loess

MAKASIS, NIKOLAS; CARRO PEREZ, MAGALI EVELIN; NARSILIO, GUILLERMO A.; BIDARMAGHZ, ASAL; FRANCISCA, FRANCO M.

ICE Themes Geothermal Energy, Heat Exchange Systems and Energy Piles

Thomas Telford Ltd

Año: 2018; p. 3 - 21

Ground-source heat pump (GSHP) systems efficiently heat and cool buildings using sustainable geothermal energy accessed via ground heat exchangers (GHEs). Loess covers vast parts of the world, about 10% of the landmass; therefore, the use of piles or ?micropiles ? is extensive in these areas, particularly where the thickness of loessic soils is significant. These deep foundations have the potential to be used as ?energy piles? in GSHP systems, with a minimal additional cost. This paper presents a case study of a representative real building in Cordoba, Argentina where foundations are also used as GHEs. The thermal properties of local soils were experimentally measured and used in detailed state-of-the-art finite element models recently developed. Results from the realistic simulations show that the partial substitution of electrical heating and cooling systems with geothermal systems could significantly reduce energy consumption and the size of associated infrastructure, despite the relatively low thermal conductivity of local loess. Moreover, accounting for natural surface thermal recharge (i.e., the effects of surface air temperature fluctuations), which is routinely ignored in GHE design, increases the ability of the energy piles to supply energy to the heat pumps in the case that was analysed. This case study shows the potential of GSHP technology in loessic environments and gives incentives to engineers to start considering the technology in their designs and practices.