Optimization of energy extraction for closed shallow geothermal systems using linear programming

Simulating thermal pollution caused by a hypothetical groundwater heat pump system under different climate, operation and hydrogeological conditions

“…The degree of thermal interference in each case was compared to the movement of a 2 °C temperature anomaly (Paly et al 2012) in the horizontal and vertical directions after 10 and 100 years. Due to the symmetric nature and large lateral extent of the model boundaries (Fig.…”

“…The allowable degree of thermal interference at a depth of 20 m after 100 years of operation time is considered to be 2 °C (Paly et al 2012). The numerical model was then run with different combinations of injection temperatures, injection rates and injection depths under four common geothermal gradients to obtain the predetermined 2 °C warming at the 20 m depth.…”

“…Some other countries impose legal regulations or recommendations based on the minimum distance to the next property line (for example, 2.5 m in Austria and 10 m in Finland), geothermal system (for example, 5-10 m in Germany) or building (for example, 5 m in Greece) as well as the temperature threshold for environmental sensitivity. For example, the allowable groundwater temperature change at a distance of 50 m from a geothermal system is less than 2 °C in the city of Stuttgart in southern Germany (Paly et al 2012), and a minimum distance of 300 m is required between a geothermal system and a drinking groundwater well in Denmark. Haehnlein et al (2010) also noted that the legal status of the use of geothermal energy can vary considerably even among the different states of a single country and that the defined threshold values are generally not based on reliable scientific analysis but rather appear to be arbitrary.…”

Formulation of a 1D finite element of heat exchanger for accurate modelling of the grouting behaviour: Application to cyclic thermal loading

“…This consists in finding the maximum level of energy production allowing a constant production for a very long time. Therefore the optimisation of single or fields of BHE is carried out in order to limit their impact or increase their efficiency [7,8,9]. Limitations of temperature variations within the soil, 25 the carrier fluid and the grouting is another constraint.…”

Geophysical Methods for Monitoring Temperature Changes in Shallow Low Enthalpy Geothermal Systems

“…In situ tests, such as thermal response tests [12,13] or laboratory measurements [14] are sometimes possible, but the values obtained may deliver only well-centered information or may not always (if not at all) be representative of in situ conditions at a larger scale. Such data are often scarce if not missing and authors often have to rely on standard calculation charts, values found in the literature, or simply default values implemented in standard software (e.g., [15][16][17][18]). In addition, the heterogeneity of the material properties and their potential anisotropy, which are difficult to detect with standard integration methods, make the problem more complex.…”