Geothermal Components Research Articles

The performance analysis of a compressed air energy storage (CAES) for peak moving with cooling, Heating, and power production

This study focuses on modeling and optimizing a multifaceted geothermal-based energy production system within the context of Denmark. The primary objectives revolve around enhancing system efficiency and reducing operational costs. The system under investigation comprises geothermal components, an organic Rankine cycle, a compressed air energy storage facility, and an absorption chiller. The organic Rankine cycle operates using refrigerants R123 and ammonia, effectively converting thermal energy into electricity and thermal energy for various applications. Optimization was carried out employing the Response Surface Method in tandem with Design-Expert software, facilitating the fine-tuning of objective functions. Two key objectives were selected: Exergy Round Trip Efficiency and cost rate, aimed at improving technical performance and curbing economic expenditure. A range of design variables were considered for optimization, including turbine and pump inlet temperatures, geothermal mass flow rate, turbine and pump efficiencies, compressor and gas turbine efficiency, inlet pressure to the compressed air energy storage tank, and evaporator pinch point temperature. The system reached an impressive exergy efficiency peak of 77.98%, accompanied by a modest cost rate of 5.48 $/h. The costliest components in the system were the compressed air energy storage unit, followed closely by organic Rankine cycle 1 and organic Rankine cycle 2. In contemplating the practical implementation of this innovative energy system, ten cities in Denmark underwent rigorous analysis, accounting for technical and economic factors. Subsequent assessments identified Aarhus as the optimal location to initiate the system. The environmental results showed that by producing 13981.9 megawatts of electricity annually in Arhus City, it is possible to help reduce CO2 emissions by 2853.2 tons of CO2/year and avoid environmental costs of 68455.3 $/year. The environmental assessment also highlighted the potential for substantial green space expansion, estimating an additional 13 hectares of green areas in the city of Aarhus, Denmark.

Structure identification of geothermal field “X” using ML-SVD method of gravity data

Understanding the main geothermal components such as clay cap, reservoir, heat source and faults structure can reduce the risk at the drilling stage. The role of the faults is very important since it can be a recharge/discharge medium of geothermal fluid. One method that can be used to identify the faults is the gravity method. The combination of the upward continuation and second vertical derivative (ML-SVD) methods is carried out to characterize the geological structure both the slope direction, depth estimation, dip estimation and type of structure. Upward continuation is carried out from a height of 0 - 2000 meters with an interval of 250 meters. SVD filter is applied at each height level. ML-SVD result shows that the fault structures at the study area have a value of dip > 70° with various fault configurations. Some faults are estimated at a certain depth under a layer of rock. ML-SVD shows a circular pattern that indicated as a caldera structure. The fault orientation of the study area tends SW-NE and NW-SE with dip perpendicular to the strike.

A tale of two lakes: the Newberry Volcano twin crater lakes, Oregon, USA

Abstract Newberry Volcano in Oregon, USA, has two small crater lakes inside its caldera: East Lake and Paulina Lake. The 50–80 m deep lakes differ in morphology, water chemistry and sediment composition, although separated only by a narrow volcanic ridge. East Lake is a terminal lake with gaseous geothermal inputs, whereas Paulina Lake has an outlet (Paulina Creek) and subaqueous, high-alkalinity hot springs. The sediment in both lakes is organic-rich and mainly consists of diatom frustules (SiO 2 ) with some volcanic ash, accumulating at sedimentation rates of 1.5–2 mm a −1 ( 210 Pb dated). In Paulina Lake the sediment has up to 14% Fe 2 O 3 of hydrothermal origin and 250 ppm As. Sediment in East Lake is Fe-poor but has up to 4 ppm Hg, and fish are also Hg-rich. Both lakes host productive ecosystems, with primary producers using geothermal CO 2 , P and Si, and nitrogen fixed by cyanobacteria ( Nostoc sp.). Water budgets and water residence times were calculated from stable isotope budgets. East Lake has a steep vertical δ 13 C (dissolved inorganic carbon, DIC) gradient, with surface δ 13 C values of up to 5.5‰, largely due to diffusional CO 2 losses and photosynthetic carbon withdrawal. Paulina Lake is better mixed, has a lower organic productivity and limited surface CO 2 evasion; its δ 13 C (DIC) gradient is small. We theorize that the lakes are fed by different geothermal components as a result of phase separation below East Lake. The gas component (CO 2 , H 2 S, Hg) enters East Lake, as indicated by the rising bubble trains in the lake. A residual fluid, depleted in Hg but rich in Si, Fe, carbonate, P and As, enters Paulina Lake. The presence of highly toxic components and the gas-charging of East Lake present natural hazards, which may change when new volcanic activity is initiated, and thus should be monitored.

Morphological characterisation of complex powder used for protective coatings for geothermal plant components

This paper aims to review the morphological characteristics, microstructures, physical and chemical properties of two complex composite powders: Ni18Cr5Si2B and Ni21Cr11Al2.5Y. These powders will be used as an option for coating geothermal turbine blades to prevent corrosion. The corrosion process in the steam turbine results in damages being recognized as the leading cause of reduced availability in geothermal power plants and is depends on temperature, mechanical and vaporous carryover of impurities and water treatment. Thermal spraying is a suitable technique for coating layers with wear and corrosion resistance. Therefore this technique could be successfully used in geothermal applications for obtaining coatings layers from new complex composite powders protecting the turbine blades from corrosions and good control of steam chemistry. The composite powders were investigated using X-ray diffraction and electronic microscopy to provide detailed information about composites morphological modifications. The results obtained after morphological evaluation are encouraging for using these composite powders as an option for coating geothermal components using thermal spraying technique.

Functionally Graded Tungsten Carbide Produced by Carburizing Method

Cemented tungsten carbide (WC-Co) is an indispensable material used in many manufacturing sectors including metalworking, oil and gas drilling, geothermal energy exploration, mining, construction, high-wear components, and other applications. The wide range of applications of WC-Co is because of its superior combination of high modulus, high hardness, wear resistance, and moderate fracture toughness. However, the wear resistance and fracture toughness of WC-Co composites are inversely related to each other. Wear resistance is often improved at the expense of the fracture toughness, and vice versa. This, in turn, limits the potential use of the material in manufacturing operations.

Noble gases as tracers identifying geothermal components in regions devoid of surface geothermal manifestations: A case study in the Baden springs area, Switzerland

Fumaroles and drowned fumaroles are formed by steam and gas, separating from ascending geothermal fluids, whereas the residual water emerges in springs. These separated phases are tagged by specific compositions of atmospheric and radiogenic noble gases, as well as by specific values of 18O, geotemperatures and age indicators. These markers may be used to recognize geothermal components in regions with no surface geothermal manifestations. In a case study at Baden, Switzerland, a drowned fumarole is identified, containing 3.3·10 −3 cm3 He/cm 3 dry gas, He/Ne = 4900 and ( 4He/ 40Ar) radiogenic = 7.3. Residual geothermal water is recognized in the springs by significant depletions of the atmospheric noble gases (retention values of Ne as low as 35%), 9.3·10 −5 Cm3 STP He/cm 3 water, He/Ne = 1200 and (4 He/ 40Ar) radiogenic = 8.9, an 18O shift of 1%o and Si0 2 and NaKCaMg geotemperatures 80° and 74 °C respectively. Discordant tritium and 14C values of 3..6 TU and 7 pmC indicate mixing of old water with of a few percent recent water. An age beyond the 14C method is indicated for the deep old end-member.