Review on the evaluation of ground-coupled heat pump and energy geostructures to exploit shallow geothermal energy with regional scale

With the large-scale exploitation and application of shallow geothermal energy, researches on ground-coupled heat pump and energy geostructures are gradually shifting from the individual, single-unit scale to the regional scale. Compared with the ground-coupled heat pump, energy geostructures have greater advantages in large-scale urban construction and underground space development due to their small area and low cost. This paper summarizes the existing research results on the theoretical potential of shallow geothermal energy in terms of thermal property parameters and subsurface urban heat island effect. It briefly describes the development forms of shallow geothermal energy and focuses on the systematic reviews of the adaptability evaluation of ground-coupled heat pump and energy geostructures at the regional scale. Additionally, a corresponding regional-scale energy geostructural evaluation system is established in terms of suitability zoning, heat exchange potential, and the effect of meeting building energy demand. This study presents an in-depth analysis of regional studies of ground-coupled heat pump in Linqu County, Shandong Province, China, Baden-Württemberg State, Germany, and energy piles in Xianlin Campus of Nanjing University, China, as case studies. It summarizes the problems in current research, and provides an outlook for future research on energy geostructures at the regional scale.