This study addresses the thermal-hydraulic-mechanical and chemical (THMC) behaviour of a research well doublet consisting of the injection well E GrSk 3/90 and the production well Gt GrSk 4/05 A(2) in the deep geothermal reservoir of Groß Schönebeck (north of Berlin, Germany). The reservoir is located between 3815 and 4247 m below sea level in the Lower Permian of the North German Basin (NGB). Both wells were hydraulically stimulated to enhance productivity. For the production well three stimulation treatments were performed in 2007: these three treatments result in a productivity increase from 2.4 m 3 /(hMPa) to

The aim of our study is to evaluate the sensitivity of the volumetric flow rate of a downhole pump in a geothermal production well on different density and viscosity functions during the startup and stationary operating phases.The geothermal fluid is modeled as an aqueous sodium chloride solution and functions for its density and viscosity are compared and applied to a model of the geothermal fluid cycle. It is shown that the deviations between viscosity functions have negligible impact on the the volumetric flow rate, while the impact of the deviations between different density functions is up to 54 % of the volumetric flow rate.

Handling of the geothermal fluid, which is typically a complex mixture of salt solution and dissolved gases, is one of the main challenges for designing and operating reliable and efficient geothermal power plants. In the geothermal fluid loop, undesired mineral precipitation and fluid-material interactions must be prevented and the design and dimensioning of all components must be adapted according to the characteristics of the geothermal fluid. This paper outlines geochemical and process engineering aspects as well as research activities in these fields and introduces the Groß Schönebeck site, which is a central site for geothermal research.

Wellhead temperature and pressure are critical parameters of a geothermal well. Their prediction requires knowledge of the geofluid properties and detailed thermal modelling of the well and formation. High salinity and gas content complicate the task. This article presents a comprehensive thermal-hydraulic wellbore model, which is parameterized and validated with data from the Gross Schoenebeck site, and used for a long-term prognosis. Geofluid properties are calculated based on the specific gas and salt contents by determining the vapour-liquid equilibrium. Nomenclature Abbreviations

The work analyses thermal and electrical solar cooling systems regarding the influence of energy storages using the open source tool open energy modelling framework (oemof). The systems are optimised with respect to lowest cost, considering various storage configurations and boundary conditions such as a required solar fraction. The results illustrate the importance of the different storage options on the size of the system components and the solar fraction. Optimal solar electrical cooling achieves solar fractions above 65%, optimal solar thermal cooling solar fractions above 87%, with a clear economic advantage for solar electrical cooling. Electrical energy storage suffers from high investment cost (compared to other storage options) and is not part of the cost optimal solutions. A sensitivity analysis shows, that even 50% decreased storage costs and increased electricity prices don't allow a profitable use of large electrical storages. To increase the solar fraction of solar electrical cooling to more than 65 % it is mandatory to use electricity storage. For both concepts, higher than cost optimal solar fractions can be achieved by increasing the respective storage sizes. Solar fractions of up to 95% are still economically reasonable. However, solar fractions above 98% result in an extreme cost increase.