Performance of geothermal energy piles in buildings: A bibliometric analysis and systematic review
Muhammad Abubakar Baffa, Zahiraniza Mustaffa, Niraku Rosmawati Ahmad, Mohamed E. El-Atroush, Nura Shehu Aliyu Yaro, Mohamed El Amine Ben Seghier
Abstract
The adoption of Geothermal Energy Piles (GEPs) as an alternative renewable energy source for heating and cooling demand of buildings continues to grow rapidly. This study presents an integrated approach wherein a bibliometric analysis and systematic review are employed to offer a holistic overview of the performance of GEPs in buildings. The trend of research in the area, key contributing countries, and keyword co-occurrence networks were analyzed. The commonly studied variables were classified and discussed based on methodologies of investigations. Findings of the studies were generally found to branch into thermal performance and thermo-mechanical behavior of GEPs. Furthermore, heat exchange rate was found to be a key factor among other variables on thermal performance and is significantly affected by flow rate and the gradient between the outlet and inlet temperature of the heat carrier fluid. Similarly, pile head settlement and shaft friction were found to be a key factor on thermo-mechanical behavior. An increase in axial stresses due to thermal loading was also commonly reported, in some cases reaching up to twice the level experienced under purely mechanical loading and should therefore not be overlooked in GEP design. Finally, this paper identifies research gaps and outlines prospective future directions for the performance of GEPs in buildings.