Small geothermal electric systems for remote powering

Entingh, Daniel J.; Easwaran, Eyob.; McLarty, Lynn

doi:10.2172/897243

Cited by 15 publications

(4 citation statements)

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“…where Revenue = net P × C el and the three later terms are particularly annualized cost of electricity, i.e., investment cost, annual operation and maintenance costs of the overall plant which are assumed to be 4% of the investment cost [31], and well cost. Well cost accounted for the geofluid-pumping and drilling costs, which are arbitrary values dependent on site-specific characteristics.…”

Section: Annual Simulation and Thermo-economic Selectionmentioning

confidence: 99%

Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

2014

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Abstract:The costs of the surface infrastructure in mid-enthalpy geothermal power systems, especially in remote areas, could be reduced by using small, modular Organic Rankine Cycle (ORC) power plants. Thermal-economic criteria have been devised to standardize ORC plant dimensions for such applications. We designed a modular ORC to utilize various wellhead temperatures (120-170 °C), mass flow rates and ambient temperatures (−10-40 °C). A control strategy was developed using steady-state optimization, in order to maximize net power production at off-design conditions. Optimum component sizes were determined using specific investment cost (SIC) minimization and mean cashflow (MCF) maximization for three different climate scenarios. Minimizing SIC did not yield significant benefits, but MCF proved to be a much better optimization function.

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Section: Annual Simulation and Thermo-economic Selectionmentioning

confidence: 99%

Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

2014

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“…A binary plant works with a geothermal resource with temperatures between 190 • C and 260 • C, using a secondary working fluid, usually organic n-pentane with a low boiling point, and a high vapor pressure, governed with low temperatures DiPippo (2016b,a); Entingh et al (1994), as indicated in Figure 2. The plant must operate through a conventional Rankine cycle, that is, the geothermal fluid gives heat to the secondary fluid through heat exchangers, where it is heated and vaporized.…”

Section: Plant Configuration and Efficiencymentioning

confidence: 99%

“…Main cost categories included in this model are briefly explained below, in accordance with Entingh et al (1994):…”

Section: Geothermal Balance Of Systemmentioning

confidence: 99%

Techno-Economic Simulation of a Geothermal Energy Generation System at the Machin Volcano in Colombia

Pantano

Betancourt

Chaves

et al. 2020

Anais Do Simpósio Brasileiro De Sistemas Elétricos 2020

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Colombian geothermal potential for power generation is interesting due to the presence of the three Andean mountain ranges and the existence of active volcanoes in junction with springs and underground reservoirs with the consequent closeness of available hydrothermal water-wells. The Machin volcano is a small mountain placed in the middle of the country, that has a considerable geothermal potential with wells in a temperature range of 160 to 260C. For that reason, a techno-economic simulation for a Geothermal Energy Generation System is proposed in this paper, using for that the System Advisor Model software. The purpose of this research is to present a more encouraging picture for public and private investors interested in exploiting this energy potential in Colombia. Simulation results include technical and economic aspects as annual and monthly energy production, geothermal resource monthly average temperature, and the Time Of Delivery Factors are also considered. Some tables with system configuration, plant and pump costs, Capacity Factor, and real and nominal Levelized Cost of Energy are also shown.

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“…On the contrary, that is the inner diameter being nearly as large as the pipe outer diameter, the flow will be hindered by the narrowness of the annular space [22,28]. In both cases, the total pressure drop to be overcome by the pump is extremely excessive.…”

Section: Optimum Diameter Ratiomentioning

confidence: 99%

Design and optimization of a downhole coaxial heat exchanger for an enhanced geothermal system (EGS)

2013

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The present study considers the design, performance analysis and optimization of a downhole coaxial heat exchanger for an enhanced geothermal system (EGS). The optimum mass flow rate of the geothermal fluid for minimum pumping power and maximum extracted heat energy was determined. In addition, the coaxial pipes of the downhole heat exchanger were sized based on the optimum geothermal mass flow rate and steady state operation. Transient effect or timedependent cooling of the Earth underground, and the optimum amount and size of perforations at the inner pipe entrance region to regulate the flow of the geothermal fluid were disregarded to simplify the analysis. The paper consists of an analytical and numerical thermodynamic optimization of a downhole coaxial heat exchanger used to extract the maximum possible energy from the Earth's deep underground (2 km and deeper below the surface) for direct usage, and subject to a nearly linear increase in geothermal gradient with depth. The thermodynamic optimization process and entropy generation minimization (EGM) analysis were performed to minimize heat transfer and fluid friction irreversibilities. An optimum diameter ratio of the coaxial pipes for minimum pressure drop in both limits of the fully turbulent and laminar fullydeveloped flow regime was determined and observed to be nearly the same irrespective of the flow regime. Furthermore, an optimum geothermal mass flow rate and an optimum geometry of the downhole coaxial heat exchanger were determined for maximum net power output.Conducting an energetic and exergetic analysis to evaluate the performance of binary power cycle, higher Earth's temperature gradient and lower geofluid rejection temperatures were observed to yield maximum first-and second-law efficiencies.

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Small geothermal electric systems for remote powering

Cited by 15 publications

References 0 publications

Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

Techno-Economic Simulation of a Geothermal Energy Generation System at the Machin Volcano in Colombia

Design and optimization of a downhole coaxial heat exchanger for an enhanced geothermal system (EGS)

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