THERMAL PERFORMANCE ANALYSIS OF GLAZED AND UNGLAZED RECEIVER OF SCHEFFLER DISH

Abstract

The impact of reradiation and convection losses from the receiver is substantial on the performance of solar parabolic dish concentrator. In this paper, an experimental and theoretical study to compare the performance of the glazed and unglazed receiver of Scheffler dish for direct steam generation is presented. Tempered glass cover is provided on aperture to reduce the reradiation and convection losses from the receiver. Improvement in the efficiency of the Scheffler dish is found due to suppressed heat losses from the receiver front surface. Overall heat loss coefficient, useful energy transfer rate to water, steam flow rate, and efficiency of the system with and without glass cover on the receiver are evaluated and compared. The average solar beam intensity during experimentation was 569 W/m2 and 600 W/m2 with the glazed and unglazed receiver respectively. The average temperature at the receiver with glazing is recorded as 425oC, even at low solar beam intensity in comparison with the unglazed receiver. Overall heat loss coefficient at the front surface of the receiver is reduced to 6.04 W/m2K. It has been observed that the Scheffler dish with a glazed receiver achieves thermal performance above 50.00% within the solar beam intensity range of 600-650 W/m2. The enhancement of 8.74% in the average thermal efficiency, with glass cover on the receiver is achieved.

Keywords

• Scheffler Dish
• Glazed Receiver
• Direct Steam Generation
• Thermal Efficiency

References

1. [1] Naik H, Baredar P, Kumar A. Medium temperature application of concentrated solar thermal technology: Indian perspective. Renew Sustain Energy Rev 2017;76:369–78. https://doi.org/10.1016/j.rser.2017.03.014.
2. [2] Salgado Conrado L, Rodriguez-Pulido A, Calderón G. Thermal performance of parabolic trough solar collectors. Renew Sustain Energy Rev 2016;67:1345–59. https://doi.org/10.1016/j.rser.2016.09.071.
3. [3] Gudekar AS, Jadhav AS, Panse S V, Joshi JB, Pandit AB. Cost effective design of compound parabolic collector for steam generation. Sol Energy 2013;90:43–50. https://doi.org/10.1016/j.solener.2012.12.020.
4. [4] Hussein AK, Li D, Kolsi L, Kata S, Sahoo B. A Review of Nano Fluid Role to Improve the Performance of the Heat Pipe Solar Collectors. Energy Procedia 2017;109:417–24. https://doi.org/10.1016/j.egypro.2017.03.044.
5. [5] Hussein AK. Applications of nanotechnology in renewable energies - A comprehensive overview and understanding. Renew Sustain Energy Rev 2015;42:460–76. https://doi.org/10.1016/j.rser.2014.10.027.
6. [6] Hussein AK. Applications of nanotechnology to improve the performance of solar collectors - Recent advances and overview. Renew Sustain Energy Rev 2016;62:767–92. https://doi.org/10.1016/j.rser.2016.04.050.
7. [7] Tian M, Su Y, Zheng H, Pei G, Li G, Riffat S. A review on the recent research progress in the compound parabolic concentrator (CPC) for solar energy applications. Renew Sustain Energy Rev 2018;82:1272–96. https://doi.org/10.1016/j.rser.2017.09.050.
8. [8] Fuqiang W, Jianyu T, Lanxin M, Chengchao W. Effects of glass cover on heat flux distribution for tube receiver with parabolic trough collector system. Energy Convers Manag 2015;90:47–52. https://doi.org/10.1016/j.enconman.2014.11.004.

9. [9] Panchal H, Patel J, Parmar K, Patel M. Different applications of Scheffler reflector for renewable energy: a comprehensive review. Int J Ambient Energy 2018:10.1080/01430750.2018.1472655. https://doi.org/10.1080/01430750.2018.1472655.
10. [10] Ruelas J, Palomares J, Pando G. Absorber design for a Scheffler-Type Solar Concentrator. Appl Energy 2015;154:35–9. https://doi.org/10.1016/j.apenergy.2015.04.107.
11. [11] Loni R, Kasaeian AB, Asli-Ardeh EA, Ghobadian B, Najafi G. Comparison study of air and thermal oil application in a solar cavity receiver. J Therm Eng 2019;5:221–9. https://doi.org/10.18186/thermal.654628.
12. [12]Loni R, Kasaeian A, Asli-Ardeh EA, Ghobadian B, Najafi G. Thermal evaluation of cavity receiver usingwater/Pg as the solar working fluid. J Therm Eng 2019;5:446–55. https://doi.org/10.18186/thermal.624341.
13. [13]Trushevskii SN, Mitina I V. Vacuum glazing units and solar collectors. Appl Sol Energy 2008;44:172–5.https://doi.org/10.3103/s0003701x08030079.
14. [14]Bisen A, Dass PP, Jain R. Parametric Studies of Top Heat Loss Coefficient of Double Glazed Flat Plate SolarCollectors. MIT Int J Mech Eng 2011;1:71–8.
15. [15]Dafle VR, Shinde NN. Design, Development & Performance Evaluation Of Concentrating MonoaxialScheffler Technology For Water Heating And Low Temperature Industrial Steam Application. Int J Eng ResAppl 2012;2:848–52.
16. [16]Uhlig R, Flesch R, Gobereit B, Giuliano S, Liedke P. Strategies enhancing efficiency of cavity receivers.Energy Procedia 2013;49:538–50. https://doi.org/10.1016/j.egypro.2014.03.058.
17. [17]Jadhav AS, Gudekar AS, Patil RG, Kale DM, Panse S V. Performance analysis of a novel and cost effectiveCPC system. Energy Convers Manag 2013;66:56–65.
18. [18]Mbodji N, Hajji A. Performance Testing of a Parabolic Solar Concentrator for Solar Cooking. J Sol EnergyEng Trans ASME 2016;138. https://doi.org/10.1115/1.4033501.
19. [19]Chandrashekara M, Yadav A. Experimental study of exfoliated graphite solar thermal coating on a receiverwith a Scheffler dish and latent heat storage for desalination. Sol Energy 2017;151:129–45.https://doi.org/10.1016/j.solener.2017.05.027.
20. [20]Chandrashekara M, Yadav A. An experimental study of the effect of exfoliated graphite solar coating with asensible heat storage and Scheffler dish for desalination. Appl Therm Eng 2017;123:111–22.https://doi.org/10.1016/j.applthermaleng.2017.05.058.
21. [21]Abedini Najafabadi H, Ozalp N. Aperture size adjustment using model based adaptive control strategy toregulate temperature in a solar receiver. Sol Energy 2018;159:20–36.https://doi.org/10.1016/j.solener.2017.10.070.
22. [22]Stefanovic VP, Pavlovic SR, Bellos E, Tzivanidis C. A detailed parametric analysis of a solar dish collector.Sustain Energy Technol Assessments 2018;25:99–110. https://doi.org/10.1016/j.seta.2017.12.005.
23. [23]Nene AA, Ramachandran S, Suyambazhahan S. Effect of Wind Flow on Convective Heat Losses fromScheffler Solar Concentrator Receivers. J Inst Eng Ser C 2018. https://doi.org/10.1007/s40032-018-0463-5.
24. [24]Renuka M, Balaji K, Sakthivadivel D, Meikandan M, Ganesh Kumar P. Selection of optimal glazing materialfor solar thermal applications using grey relational analysis. Int J Ambient Energy 2019;0:1–13.https://doi.org/10.1080/01430750.2018.1563820.
25. [25]Li D, Li Z, Zheng Y, Liu C, Hussein AK, Liu X. Thermal performance of a PCM-filled double-glazing unitwith different thermophysical parameters of PCM. Sol Energy 2016;133:207–20.https://doi.org/10.1016/j.solener.2016.03.039.
26. [26]Hussein, Ahmed Kadhim A AW. Applications Of Nanotechnology To Enhance The Performance of TheDirect Absorption Solar Collectors. J Therm Eng 2016;2:529–40.
27. [27]Kumar A, Shukla SK. Experimental and numerical analysis of a helical coil solar cavity receiver: Thermal oilas the heat transfer fluid. Int J Green Energy 2019;16:716–32.https://doi.org/10.1080/15435075.2019.1619566.
28. [28]Bopche SB, Kumar S. Experimental investigations on thermal performance characteristics of a solar cavityreceiver. Int J Energy Environ Eng 2019;10:463–81. https://doi.org/10.1007/s40095-019-00321-4.
29. [29]López O, Baños A, Arenas A. On the thermal performance of flat and cavity receivers for a parabolic dishconcentrator and low/medium temperatures. Sol Energy 2020;199:911–23.https://doi.org/10.1016/j.solener.2019.07.056.
30. [30]MNRE. Scheffler Dish based Solar System: Operations and Maintenance Manual. 2014.
31. [31]Michaelides IM, Lee WC, Wilson DR, Votsis PP. Computer simulation of the performance of athermosyphon solar water-heater. Appl Energy 1992;41:149–63. https://doi.org/10.1016/0306-2619(92)90042-A.
32. [32]Fang Y, Arya F. Evacuated glazing with tempered glass. Sol Energy 2019;183:240–7. https://doi.org/10.1016/j.solener.2019.03.021.
33. [33]Munir A, Hensel O, Scheffler W. Design principle and calculations of a Scheffler fixed focus concentrator formedium temperature applications. Sol Energy 2010;84:1490–502.https://doi.org/10.1016/j.solener.2010.05.011.
34. [34]Duffie JA, Beckman WA. Solar Engineering of Thermal Processes. Fourth edi. Hoboken, New Jersey: JohnWiley & Sons; 2013.
35. [35]Frank P. Incropera, David P. Dewitt, Theodore L. Bergman ASL. Fundamentals of Heat and Mass Transfer.John Wiley & Sons, Inc; 2007.
36. [36]Oosthuizen PH, Kalendar AY. Natural convective heat transfer from short inclined cylinders. 2014.https://doi.org/10.1007/978-3-319-02459-2.
37. [37]J. P. Holman. Heat Transfer. sixth. McGraw-Hill; 1986.
38. [38]Kumar S, Mullick SC. Glass cover temperature and top heat loss coefficient of a single glazed flat platecollector with nearly vertical configuration. Ain Shams Eng J 2012;3:299–304.https://doi.org/10.1016/j.asej.2012.03.008.
39. [39]R. J. Moffat. Describing the uncertainties in experimental results. Exp Therm Fluid Sci 1988:3–17.