Numerical study of conduction and radiation heat losses from vacuum annulus in parabolic trough receivers

Abstract

Parabolic trough receiver is a key component to convert solar energy into thermal energy in the parabolic trough solar system. The heat loss of the receiver has an important influence on the thermal efficiency and the operating cost of the power station. In this paper, conduction and radiation heat losses are analyzed respectively to identify the heat loss mechanism of the receiver. A 2-D heat transfer model is established by using the direct simulation Monte Carlo method for rarefied gas flow and heat transfer within the annulus of the receiver to predict the conduction heat loss caused by residual gases. The numerical results conform to the experimental results, and show the temperature of the glass envelope and heat loss for various conditions in detail. The effects of annulus pressure, gas species, temperature of heat transfer fluid, and annulus size on the conduction and radiation heat losses are systematically analyzed. Besides, the main factors that cause heat loss are analyzed, providing a theoretical basis for guiding the improvement of receiver, as well as the operation and maintenance strategy to reduce heat loss.

Graphical abstract

Keywords

parabolic trough receiver / vacuum annulus / rarefied gas / DSMC (direct simulation Monte Carlo) / heat loss

References

[1] Espinosa-Rueda G, Navarro Hermoso J, Martínez-Sanz N, Gallas-Torreira M. Vacuum evaluation of parabolic trough receiver tubes in a 50 MW concentrated solar power plant. Solar Energy, 2016, 139: 36–46

[2] Liu J, Lei D, Li Q. Vacuum lifetime and residual gas analysis of parabolic trough receiver. Renewable Energy, 2016, 86: 949–954

[3] Daniel P, Joshi Y, Das A K. Numerical investigation of parabolic trough receiver performance with outer vacuum shell. Solar Energy, 2011, 85(9): 1910–1914

[4] Lobón D, Valenzuela L, Baglietto E. Modeling the dynamics of the multiphase fluid in the parabolic-trough solar steam generating systems. Energy Conversion and Management, 2014, 78(78): 393–404

[5] Ren Y, Lei D, Wang Z. Experimental analysis of residual gas of vacuum annulus in parabolic through solar receivers. In: AIP Conference Proceedings 2126, 2019, 120017: 1–10

[6] He Y, Wang K, Qiu Y, Du B, Liang Q, Du S. Review of the solar flux distribution in concentrated solar power: non-uniform features, challenges, and solutions. Applied Thermal Engineering, 2019, 149: 448–474

[7] Reddy K, Balaji S, Sundararajan T. Heat loss investigation of 125 kW_th solar LFR pilot plant with parabolic secondary evacuated receiver for performance improvement. International Journal of Thermal Sciences, 2018, 125: 324–341

[8] Kearney D, Price H. Chapter 6: Recent Advances in Parabolic Trough Solar Power Plant Technology. Boulder Co American Solar Energy Society Inc, 2005

[9] Kutscher C, Mehos M, Turchi C, Glatzmaier G. Line-focus solar power plant cost reduction plan (milestone report). Office of Scientific & Technical Information Technical Reports, 2010

[10] Lei D, Fu X, Ren Y, Yao F, Wang Z. Temperature and thermal stress analysis of parabolic trough receivers. Renewable Energy, 2019, 136: 403–413

[11] Li J, Wang Z, Lei D, Li J. Hydrogen permeation model of parabolic trough receiver tube. Solar Energy, 2012, 86(5): 1187–1196

[12] Price H, Forristall R, Wendelin T, Lewandowski A, Moss T, Gummo C. Field survey of parabolic trough receiver thermal performance. In: Proceedings of ISEC2006: ASME International Solar Energy Conference, Denver, Colorado, USA, 2006

[13] Prahl C, Röger M, Stanicki B, Hilgert C. Absorber tube displacement in parabolic trough collectors—a review and presentation of an airborne measurement approach. Solar Energy, 2017, 157(157): 692–706

[14] Ratzel A C, Hickox C E, Gartling D K. Techniques for reducing thermal conduction and natural convection heat losses in annular receiver geometries. Journal of Heat Transfer, 1979, 101(1): 108-113

[15] Tang Z, Zhao X P, Li Z Y, Tao W Q. Multi-scale numerical analysis of flow and heat transfer for a parabolic trough collector. International Journal of Heat and Mass Transfer, 2017, 106: 526–538

[16] Roesle M, Good P, Coskun V, Steinfeld A. Analysis of conduction heat loss from a parabolic trough solar receiver with active vacuum by direct simulation Monte Carlo. Numerical Heat Transfer, 2012, 62(5): 432–444

[17] Burkholder F, Brandemuehl M, Kutscher C, Wolfrum Ed. Heat conduction of inert gas-hydrogen mixtures in parabolic trough receivers. In: ASME 2008, International Conference on Energy Sustainability Collocated with the Heat Transfer, Fluids Engineering, and Energy Nanotechnology Conferences, Jacksonville, Florida, USA, 2008: 449–458

[18] Yu Q, Mi J, Lang Y, Du M, Li S, Yang H, Hao L, Liu X, Jiang L. Thermal properties of high temperature vacuum receivers used for parabolic trough solar thermal power system. Progress in Natural Science: Materials International, 2017, (27): 410–415

[19] Setien E, López-Martín R, Valenzuela L. Methodology for partial vacuum pressure and heat losses analysis of parabolic troughs receivers by infrared radiometry. Infrared Physics & Technology, 2019, 98: 341–353

[20] Yao F, Lei D, Yu K, Han Y, Yao P, Wang Z, Fang Q, Hu Q. Experimental study on vacuum performance of parabolic trough receivers based on a novel non-destructive testing method. Energies, 2019, 12(23): 4531

[21] Kumar D, Kumar S. Simulation analysis of overall heat loss coefficient of parabolic trough solar collector at computed optimal air gap. Energy Procedia, 2017, 109: 86–93

[22] Lei D, Li Q, Wang Z, Li J, Li J. An experimental study of thermal characterization of parabolic trough receivers. Energy Conversion and Management, 2013, 69(5): 107–115

[23] Hilgert C, Jung C, Wasserfuhr C, Leon J, Valenzuela L. Qualification of silicone based HTF for parabolic trough collector applications. In: AIP Conference Proceedings 2126, 2019, 080003: 1–10

[24] Chang C, Sciacovelli A, Wu Z, Li X, Li Y, Zhao M, Deng J, Wang Z, Ding Y. Enhanced heat transfer in a parabolic trough solar receiver by inserting rods and using molten salt as heat transfer fluid. Applied Energy, 2018, 220: 337–350

[25] Nunes V, Queirós C, Lourenço M, Santos F J V, Nieto de Castro C A. Molten salts as engineering fluids – a review: Part I. Molten alkali nitrates. Applied Energy, 2016, 183: 603–611

[26] Muñoz-Anton J, Biencinto M, Zarza E, Díez L E. Theoretical basis and experimental facility for parabolic trough collectors at high temperature using gas as heat transfer fluid. Applied Energy, 2014, 135: 373–381

[27] Aguilar R, Valenzuela L, Avila-Marin A L, Garcia-Ybarra P L. Simplified heat transfer model for parabolic trough solar collectors using supercritical CO₂. Energy Conversion and Management, 2019, 196: 807–820

[28] Qiu Y, Li M, He Y, Tao W. Thermal performance analysis of a parabolic trough solar collector using supercritical CO₂ as heat transfer fluid under non-uniform solar flux. Applied Thermal Engineering, 2017, 115: 1255–1265

[29] Wu Z, Lei D, Yuan G, Shao J, Zhang Y, Wang Z. Structural reliability analysis of parabolic trough receivers. Applied Energy, 2014, 123: 232–241

[30] Forristall R. Heat transfer analysis and modeling of a parabolic trough solar receiver implemented in engineering equation solver. National Renewable Energy Lab., Golden, CO. (US) , Technical Report, 2003, NREL/TP-550-34169

[31] Shen C. Rarefied Gas Dynamics. Springer Nature, 2005, 17(5): 90–91

[32] Bird G. Molecular Gas Dynamics and the Direct Simulation of Gas Flows. Oxford: Clarendon Press, 1994

[33] Bird G, Gallis M, Torczynski J, Rader D J. Accuracy and efficiency of the sophisticated direct simulation Monte Carlo algorithm for simulating non-continuum gas flows. Physics of Fluids, 2009, 21(1): 541–546

[34] Song S, Yovanovich M. Correlation of thermal accommodation coefficient for engineering surfaces. In: Proceedings of the 24th National Heat Transfer Conference and Exhibition, Pittsburgh, PA, USA, 1987: 107–116

[35] Burkholder F. Transition regime heat conduction of argon/hydrogen and xenon/hydrogen mixtures in a parabolic trough receiver. Dissertation for the Docotoral Degree. Boulder: University of Colorado Boulder, 2011

Acknowledgments

This work was funded by the National Key R&D Program of China (No. 2019YFE0102000) and the National Natural Science Foundation of China (Grant No. 51476165).

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