The use of shallow geothermal energy (SGE) systems to acclimatize buildings has increased exponentially in the Netherlands and worldwide. In certain areas, SGE systems are constructed in aquifers also used for drinking water supply raising the question of potential groundwater quality impact. Impacts of Shallow Geothermal Energy on Groundwater Quality provides a hydrochemical and geomicrobial overview of the effects of ground source heat pumps and aquifer thermal energy storage. The area is investigated with field and laboratory experiments, and reactive transport models, showing that shallow geothermal energy systems can influence groundwater quality in a number of ways. Most prominent in open ground source heating systems operating at low temperature (20°C) is the physical mixing of deep and shallow groundwater of different quality distorting the natural water quality stratification in aquifers. At a temperature of 25°C and beyond certain trace elements were observed to mobilize in laboratory experiments, and beyond 40°C redox conditions change significantly while the microbial community shift towards a thermophilic community. div Based on the results of this research, guidelines are presented for monitoring and permitting of SGE systems. The book is a useful resource for regulators of these systems, water companies and installers of the SGE systems. Author: Matthijs Bonte, Amsterdam, The Netherlands

This book is the outcome of more than a decade of research and technical development activities at Spain’s Geological Survey (IGME) concerning shallow geothermal energy, which were pursued in collaboration with other public bodies and European entities. It presents a compilation of papers on the theoretical foundations of, and practical aspects needed to understand the thermal regime of the topmost subsoil, up to 400 m deep, and the exceptional properties that this underground environment offers, which make it the ideal thermal reservoir for heating, ventilation, and air conditioning (HVAC). In the book’s first section, the basic theory of thermodynamics as applied to shallow geothermal energy, heat transfer and fluid mechanics in the geological porous medium is developed. The nature of the subsoil’s thermal regime in general and in the urban environment in particular is described. The second section introduces readers to the fundamental aspects of thermal installations equipped with geothermal heat pumps, describes the types of geothermal exchangers most commonly used, and reviews the techniques used to obtain the thermal parameters of the terrain. It also discusses the potential environmental impacts of shallow geothermal activity and corresponding management strategies, as well as the legal aspects of its regulation for the governance of shallow geothermal resources in the EU in general and Spain in particular. In closing, the book highlights examples of the methodologies’ applications, developed by IGME in the city of Zaragoza and the Canary Islands. The theoretical foundations, systematics and concrete applications make the book a valuable reference source for hydrogeologists, engineers and specialized technicians alike.