Heating performance characteristics of the ground source heat pump system with energy-piles and energy-slabs

Energy foundations and other thermo-active ground structure, energy wells, energy slabs, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy-piles and energy-slabs filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The ground source heat pump system with energy-pile and energy-slab presented high heating performance due to the stability of entering water temperature from the ground loop heat exchanger. The minimum COPs of the heat pump unit for the energy-pile and energy-slab system were 4.2 and 4.5, respectively. These results are higher than the minimum COP certification standard of 3.45 for a closed ground loop heat pump unit.