Enhanced heat transfer in a parabolic trough solar receiver by inserting rods and using molten salt as heat transfer fluid

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS (Solar Electric Generating Systems located in Mojave Desert, California) plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems exist, and the quantification of performance and electricity cost using preliminary cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% CaNO32, 7% NaNO3, and 45% KNO3). Assuming a two-tank storage system and a maximum operation temperature of 450°C, the evaluation showed that the levelized electricity cost can be reduced by 14.2% compared to a state-of-the-art parabolic trough plant such as the SEGS plants. If higher temperatures are possible, the improvement may be as high as 17.6%. Thermocline salt storage systems offer even greater benefits.

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Development of Molten-Salt Heat Transfer Fluid Technology for Parabolic Trough Solar Power Plants - Public Final Technical Report

10.2172/1090096 ◽

2013 ◽

Cited By ~ 9

Author(s):

Dylan C. P. Grogan

Keyword(s):

Heat Transfer ◽

Molten Salt ◽

Power Plants ◽

Solar Power ◽

Heat Transfer Fluid ◽

Parabolic Trough ◽

Technical Report ◽

Solar Power Plants

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Evaluation of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field

Solar Energy ◽

10.1115/sed2002-1065 ◽

2002 ◽

Cited By ~ 19

Author(s):

D. Kearney ◽

U. Herrmann ◽

P. Nava ◽

B. Kelly ◽

R. Mahoney ◽

...

Keyword(s):

Heat Transfer ◽

Molten Salt ◽

Eutectic Mixture ◽

Heat Transfer Fluid ◽

Diphenyl Oxide ◽

Parabolic Trough ◽

Solar Salt ◽

Electricity Cost ◽

Critical Issues ◽

Solar Field

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems existed, and the quantification of performance and electricity cost using preliminary, but reasonable, cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO3)2, 7% NaNO3, and 45% KNO3).

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Corrigendum to “Object-oriented modeling for the transient performance simulation of parabolic trough collectors using molten salt as heat transfer fluid” [Solar Energy 95 (2013) 192–215]

Solar Energy ◽

10.1016/j.solener.2014.08.014 ◽

2014 ◽

Vol 109 ◽

pp. 93-94

Author(s):

Fritz Zaversky ◽

Rodrigo Medina ◽

Javier Garcìa-Barberena ◽

Marcelino Sànchez ◽

David Astrain

Keyword(s):

Heat Transfer ◽

Solar Energy ◽

Molten Salt ◽

Object Oriented ◽

Heat Transfer Fluid ◽

Transient Performance ◽

Parabolic Trough ◽

Performance Simulation

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Heat transfer enhancement of a molten salt parabolic trough solar receiver with concentric and eccentric pipe inserts

Energy Procedia ◽

10.1016/j.egypro.2017.12.103 ◽

2017 ◽

Vol 142 ◽

pp. 624-629 ◽

Cited By ~ 6

Author(s):

Chun Chang ◽

Xiaodong Peng ◽

Binjian Nie ◽

Guanghui Leng ◽

Chuan Li ◽

...

Keyword(s):

Heat Transfer ◽

Molten Salt ◽

Heat Transfer Enhancement ◽

Transfer Enhancement ◽

Parabolic Trough ◽

Solar Receiver

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Feasibility Study of Freeze Recovery Options in Parabolic Trough Collector Plants Working with Molten Salt as Heat Transfer Fluid

Energies ◽

10.3390/en12122340 ◽

2019 ◽

Vol 12 (12) ◽

pp. 2340 ◽

Cited By ~ 5

Author(s):

Cristina Prieto ◽

Alfonso Rodríguez-Sánchez ◽

F. Ruiz-Cabañas ◽

Luisa Cabeza

Keyword(s):

Heat Transfer ◽

Molten Salt ◽

Molten Salts ◽

Heat Transfer Fluid ◽

Operational Experience ◽

Parabolic Trough ◽

Solar Salt ◽

Parabolic Trough Collector ◽

Overall Performance ◽

Solar Field

Parabolic trough collector (PTC) technology is currently the most mature solar technology, which has led to the accumulation of relevant operational experience. The overall performance and efficiency of these plants depends on several components, and the heat transfer fluid (HTF) is one of the most important ones. Using molten salts as HTFs has the advantage of being able to work at higher temperatures, but it also has the disadvantage of the potential freezing of the HTF in pipes and components. This paper models and evaluates two methods of freeze recovery, which is needed for this HTF system design: Heat tracing in pipes and components, and impedance melting in the solar field. The model is used to compare the parasitic consumption in three molten salts mixtures, namely Solar Salt, HiTec, and HiTec XL, and the feasibility of this system in a freezing event. After the investigation of each of these subsystems, it was concluded that freeze recovery for a molten salt plant is possible.

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Thermofluidynamic Model and Comparative Analysis of Parabolic Trough Collectors Using Oil, Water/Steam, or Molten Salt as Heat Transfer Fluids

Journal of Solar Energy Engineering ◽

10.1115/1.4001399 ◽

2010 ◽

Vol 132 (2) ◽

Cited By ~ 48

Author(s):

M. J. Montes ◽

A. Abánades ◽

J. M. Martínez-Val

Keyword(s):

Heat Transfer ◽

Molten Salt ◽

Point Of View ◽

Heat Transfer Fluid ◽

Steam Generation ◽

Parabolic Trough ◽

Water Steam ◽

Temperature And Pressure ◽

Energy Gains ◽

Gains And Losses

This paper describes the development and use of a thermofluidynamic model for parabolic trough collectors, specifically suited for carrying out systematic calculations on different design options. The model is based on detailed energy balances, and it has been applied to evaluate collector thermal performances with different working fluids: oil, molten salt, or water/steam. For each heat transfer fluid technology, four parameters have been analyzed: collector length, absorber tube diameter, working temperature, and pressure. The influence of these factors has been studied from the point of view of heat loss, pressure drop, energy, and exergy efficiencies. Exergy is considered the suitable magnitude to guide any optimization process in this field, because it accounts for all relevant energy gains and losses, characterized by their corresponding temperature and pressure. Preliminary conclusions point out that direct steam generation is more efficient than oil and molten salt systems.

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