A Finite-Time Thermodynamic Framework for Optimizing Solar-Thermal Power Plants

McMahan, Andrew C.; Klein, S.A.; Reindl, Douglas T.

doi:10.1115/1.2769689

Cited by 35 publications

(10 citation statements)

References 5 publications

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“…The dimensionless hyperbolic type equations are solved numerically by the method of characteristics. This numerical method overcomes the numerical difficulties encountered in McMahan's work-explicit, implicit, and the restriction on infinite-NTU method (McMahan, 2006(McMahan, , 2007. The current model yields a direct solution to the discretized equations (with no iterative computation needed) and completely eliminates any computational overhead.…”

Section: Numerical Methods and Solution To Governing Equations 531 mentioning

confidence: 97%

“…(41) are independent of * z , * t , f θ , and r θ , thus they can be evaluated once for all. Therefore, the numerical computation takes a minimum of computing time, and is much more efficient than the method applied in references (McMahan, 2006(McMahan, , 2007. The above numerical integrations used the trapezoidal rule; the error of such an implementation is not straightforwardly analyzed but the formal accuracy is on the order of ) t ( O 2 * Δ for functions (Ferziger, 1998) such as those solved in this study.…”

Section: Numerical Methods and Solution To Governing Equations 531 mentioning

confidence: 99%

“…The solution for the complete power plant with thermocline storage provided by the TRNSYS model in Kolb's work (Kolb & Hassani, 2006) cites the short time step requirement for the differential equations of the thermocline as one major source of computer time consumption. To overcome the problems encountered in the explicit and implicit methods, McMahan et al also proposed an infinite-NTU method (McMahan, 2006(McMahan, , 2007. This model however is limited to the case in which the heat transfer of the fluid compared to the heat storage in fluid is extremely large.…”

Section: Numerical Methods and Solution To Governing Equations 531 mentioning

confidence: 99%

See 2 more Smart Citations

Transient Heat Transfer and Energy Transport in Packed Bed Thermal Storage Systems

Li¹,

Lew²,

Karaki³

et al. 2011

Developments in Heat Transfer

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Section: Numerical Methods and Solution To Governing Equations 531 mentioning

confidence: 97%

Section: Numerical Methods and Solution To Governing Equations 531 mentioning

confidence: 99%

Section: Numerical Methods and Solution To Governing Equations 531 mentioning

confidence: 99%

See 1 more Smart Citation

Transient Heat Transfer and Energy Transport in Packed Bed Thermal Storage Systems

Li¹,

Lew²,

Karaki³

et al. 2011

Developments in Heat Transfer

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“…In this section, a simplified model of a Rankine cycle solar thermal power plant is developed based on previous work [1][2][3][4][5][6][7][8]. In our analysis, we choose to treat solar irradiation as an incident heat flux, specified as a rate of heat input per unit solar collector area, s q  .…”

Section: Optimal Receiver Irradiance Of Solar Thermal Plantsmentioning

confidence: 99%

Optimal concentration and temperatures of solar thermal power plants

McGovern

Smith

2012

Energy Conversion and Management

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Publication informationEnergy Conversion and Management, Publisher Elsevier Item record/more information http://hdl.handle.net/10197/4904 Publisher's statementThis is the author's version of a work that was accepted for publication in Energy Conversion and Management. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Energy Conversion and Management (60, , (2012) Abstract:Using simple, finite-time, thermodynamic models of solar thermal power plants, the existence of an optimal solar receiver temperature has previously been demonstrated in literature. Scant attention has been paid, however, to the presence of an optimal level of solar concentration at which the conversion of incident sunlight to electricity (solar-to-electric efficiency) is maximized. This paper addresses that gap. The paper evaluates the impact, on the design of Rankine-cycle solar-trough and solar-tower power plants, of the existence of an optimal receiver temperature and an optimal level of solar concentration. Mathematical descriptions are derived describing the solar-to-electric efficiency of an idealized solar thermal plant in terms of its receiver temperature, ambient temperature, the receiver irradiance (radiation striking unit receiver area), solar receiver surface to working fluid conductance, condenser conductance, solar collector efficiency, convective loss coefficients and radiative loss coefficients. Using values from the literature appropriate to direct-steam and molten-salt plants, curves of optimal solar receiver temperature, and optimal solar-to-electric conversion efficiency, are generated as a function of receiver irradiance. The analysis shows that, as the thermal resistance of the solar receiver and condenser increases, the optimal receiver temperature increases whilst the optimal receiver irradiance decreases. The optimal level of receiver irradiance, for solar thermal plants employing a service fluid of molten salts, is found to occur within a range of values achievable using current solar tower technologies. The tradeoffs (in terms of solar-to-electric efficiency) involved in using molten salts rather than direct steam in the case of solar towers and solar troughs are investigated. The optimal receiver temperatures calculated with the model suggest the use of sub-critical Rankine cycles for solar trough plants, but super-critical Rankine cycles for solar tower plants, if the objective is to maximize solar-to-electric efficiency.

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“…Several investigators have made an economic analysis of a particular ORC system, e.g. [1,2], but relatively few attempts have been made to create explicit integrated thermo-physical and economic models for an ORC system using some specified or unspecified thermal source [3,4]. To date no comprehensive general model (including thermodynamic, mechanical, electrical and economics components) for a solar thermal driven ORC, with its unique thermal source fluctuation characteristics, has been developed.…”

Section: Introductionmentioning

confidence: 99%

Sorce: A Design Tool for Solar Organic Rankine Cycle Systems in Distributed Generation Applications

Orosz¹,

Quoilin²,

Hemond³

2010

Proceedings of the EuroSun 2010 Conference

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SynopsisRecent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine. Much existing research touches on aspects of the underlying physics and mechanics of this technology, but a holistic treatment including economic evaluation is lacking. Design and analysis tools are needed to specify the solar collector and power block configurations for meeting performance and financial targets for a range of applications in disparate environments. In this paper we present the Solar Organic Rankine Cycle Economic (SORCE) model combining semi-empirical multi-physics computation modules for solar resource and site environmental parameter characterization along with optical, thermal and electromechanical performance prediction of trough collectors and ORC systems with technical specifications and costs of standard system equipment. The model is tested with data from experimental solar ORC systems at MIT and deployed in Lesotho, southern Africa (29°12'48.44"S, 27°51'37.36"E). SORCE is available for download 1 as an executable program derived from Engineering Equation Solver (EES) that enables site-specific evaluation of a solar ORC system for performance and cost comparison with alternatives (e.g. wind, solar PV, diesel, etc.).

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A Finite-Time Thermodynamic Framework for Optimizing Solar-Thermal Power Plants

Cited by 35 publications

References 5 publications

Transient Heat Transfer and Energy Transport in Packed Bed Thermal Storage Systems

Transient Heat Transfer and Energy Transport in Packed Bed Thermal Storage Systems

Optimal concentration and temperatures of solar thermal power plants

Sorce: A Design Tool for Solar Organic Rankine Cycle Systems in Distributed Generation Applications

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