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.

Key words： parabolic trough receiver; vacuum annulus; rarefied gas; DSMC (direct simulation Monte Carlo); heat loss

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).

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