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AbstractThis paper presents the experimental plans and designs as well as examples of predictive modeling of a pilot-scale CO2 injection experiment at the Heletz site (Israel). The overall objective of the experiment is to find optimal ways to characterize CO2 -relevant in-situ medium properties, including field-scale residual and dissolution trapping, to explore ways of characterizing heterogeneity through joint analysis of different types of data, and to detect leakage. The experiment will involve two wells, an injection well and a monitoring well. Prior to the actual CO2 injection, hydraulic, thermal and tracer tests will be carried out for standard site characterization. The actual CO2 injection experiments will include (i) a single well injection-withdrawal experiment, with the main objective to estimate in-situ residual trapping and (ii) a two-well injection-withdrawal test with injection of CO2 in a dipole mode (injection of CO2 in one well with simultaneous withdrawal of water in the monitoring well), with the objective to understand the CO2 transport in heterogeneous geology as well as the associated dissolution and residual trapping. Tracers will be introduced in both experiments to further aid in detecting the development of the phase composition during CO2 transport. Geophysical monitoring will also be implemented. By means of modeling, different experimental sequences and injection/withdrawal patterns have been analyzed, as have parameter uncertainties. The objectives have been to (i) evaluate key aspects of the experimental design, (ii) to identify key parameters affecting the fate of the CO2 and (iii) to evaluate the relationships between measurable quantities and parameters of interest.

AbstractWe measured dissolved inorganic carbon (DIC) stable isotopes (813CDIC in ‰) of brine from an observation well within the first aquifer above the CO2 reservoir at the Ketzin pilot site, to test weather these can detect potential CO2 leakage. The monitoring revealed that DIC concentrations and 813CDIC values were masked by the used high alkaline drilling mud, even eight months after well development. However, subsequent changes in 813CDIC and DIC from of -27 ‰ and 165mg L−1 to -23.5 ‰ and 116mg L−1 reflect most likely a shift towards pristine values of the aquifer.

Abstract The complete cycle of specific processes related to the geological storage of CO 2 is investigated in detail at Ketzin since 2004. The scientific monitoring program targets different depths of the involved area and addresses the safety and reliability of the storage. The surface monitoring comprises long-term soil CO 2 flux measurements and soil gas analyses. Annual mean values of soil CO 2 fluxes ranged from 2.4 to 3.4 µmol m -2 s -1 before the injection started (2005-2008) and from 2.3 to 3.5 µmol m -2 s -1 during and after CO 2 injection (2009-2016) and thus do not indicate an upward migration of the injected CO 2 .

AbstractA high-pressure/high-temperature reactor has been used to lead PVT and H2-solubility experiments in saline solutions covering conditions for which no data are available in literature: salinity up to halite concentration, pressure up to 200bar and temperature up to 373K. The hereby presented preliminary results show significant deviations from theoretical models. Further analysis and more measurements are needed to assess precision and reproducibility of these measurements; however they pinpoint the importance of experimental work to reliably constrain predictive models.

Abstract In binary geothermal power plants based on the Organic Rankine Cycle (ORC) typically shell-and-tube heat exchangers are used as evaporators. In the shell-side, nucleate boiling of the working fluid takes place on the outer surface of the tubes. For the replacement of fluids with high global warming potential (GWP) or selection of efficient working fluids, a comprehensive evaluation has to be performed. Therefore, the knowledge about the nucleate boiling heat transfer coefficient (HTC) in combination with the electrical power output is necessary. In this study, the focus is led on the investigation of the replacement of R245fa by the low GWP fluid R1233zd(E) in geothermal applications. The nucleate boiling HTC on a horizontal tube and the electrical power of a 1 kW scroll expander are simultaneously measured with an ORC test rig for both fluids. The thermal input is provided by an electrically heated preheater and evaporator. Nucleate boiling takes place on a plain copper tube with an outer diameter of 32 mm and a heated length of 822 mm. The surface temperature of the copper tube is determined by thermocouples within the tube in consideration of thermal conduction. The obtained results, regarding power output as well as heat transfer characteristics, show that the working fluid R245fa performs better at equal saturation temperatures due to the higher density and pressure, and the lower viscosity. The HTC of R245fa is exemplarily up to 43.2 % increased in comparison to R1233zd(E).

AbstractDecreasing water resources and steadily rising water demand drive research towards new approaches for safe and reliable water supply for the municipal, agricultural and industrial sectors. One solution for fresh water provision is sea water desalination using solar thermal energy. This paper describes the coupling of a Multi Effect Distillation (MED) plant with a Clausius-Rankine cycle powered by a solar central receiver system. A steady state model of an MED plant is developed and a correlation for the Gained Output Ratio (GOR) as function of heating steam temperature, specific seawater massflow and specific heat transfer surface of the desalination plant is deduced. This correlation is integrated into a model of a central receiver plant, comprising the heliostat field, a molten salt receiver system, two-tank storage and the steam cycle. A showcase simulation for the location Al-Kosseir, Egypt is performed to show the trade-off between electricity and water production for a cogeneration situation.

AbstractGasifier based cogeneration power plants were installed in a large number of rice mills in West Bengal in India. The present study reports on performance of the rice mill cogeneration plants in the state. Viability of the programme has also been questioned in this paper.

Abstract With rising population, development, and environmental pollution, availability of potable water is shrinking fast. Thus, it is required to focus on the distillation of available water. Solar Still is one of the promising technologies available to purify water because of its low cost, energy, and skill requirement. However, the efficiency of present technology is low, so it is required to advance the designs of existing solar stills. In this study, a multi-phase three-dimensional CFD model of a simple solar still developed for simulation with using ANSYS FLUENT. The simulation has been done for transient state to validate the results with experimental data for climate conditions of Jaipur (26°13’N, 75°49’E). Within the scope of this study, simulation results were found to be in good agreement with the experimental data. It is also examined that thermal efficiency of the Solar Still is higher from 16:00 to 17:00 hrs. Parametric analyses has been done to enhance the productivity of Solar Still. Different materials were used in the basin to increase the heat capacity, absorption capacity and the evaporation rate. The impact of varying the depth of the basin water was also studied. It has been found that the Solar Still have more productivity for low water depth.