"Preface The thermal use of the shallow subsurface is increasingly promoted and implemented as one of many promising measures for saving energy. The energy extracted from such systems is referred to as shallow geothermal energy or low-enthalpy energy. Open and closed systems are distinguished usually consisting of boreholes combined with heat pumps. A series of questions arises with respect to the design, the management of underground and groundwater heat extraction systems, such as the sharing of the thermal resource, the long-term sustainability of the thermal use, and the assessment of its long-term potential. For the proper design of thermal systems, it is necessary to assess their impact on underground and groundwater temperatures. The theoretical basis of heat transport in soil and groundwater systems is therefore introduced, and the essential thermal properties are discussed. In the planning and design of geothermal systems, hydrogeological and thermal site investigations have to be combined with modeling. Therefore, a series of mathematical tools and simulation models based on analytical and numerical solutions of the heat transport equation are presented. Finally, some case studies are introduced for illustration. The book is directed toward MSc students in civil or environmental engineering, engineering geology, and hydrogeology and junior professionals. It provides a platform of principles and outlines the essential models and parameters to assess and design technical systems for the thermal use of the shallow underground"-- Provided by publisher.