International Scientific Journal


Spherical cavity receiver of solar concentrator is made up of Cu tubing material having cavity diameter 385 mm to analyze the different heat losses such as conduction, convection and radiation. As the convection loss plays major role in heat loss analysis of cavity receiver, the experimental analysis is carried out to study convective heat loss for the temperature range of 55-75°C at 0°, 15°, 30°, 45°, 60°, and 90° inclination angle of downward facing cavity receiver. The numerical analysis is carried out to study convective heat loss for the low temperature range (55-75°C) as well as high temperature range (150-300 °C) for no wind condition only. The experimental set-up mainly consists of spherical cavity receiver which is insulated with glass wool insulation to reduce the heat losses from outside surface. The numerical analysis is carried out by using CFD software and the results are compared with the experimental results and found good agreement. The result shows that the convective loss increases with decrease in cavity inclination angle and decreases with decrease in mean cavity receiver temperature. The maximum losses are obtained at 0° inclination angle and the minimum losses are obtained at 90° inclination angle of cavity due to increase in stagnation zone in to the cavity from 0° to 90° inclination. The Nusselt number correlation is developed for the low temperature range 55-75°C based on the experimental data. The analysis is also carried out to study the effect of wind speed and wind direction on convective heat losses. The convective heat losses are studied for two wind speeds (3 m/s and 5 m/s) and four wind directions [α is 0° (Side-on wind), 30°, 60°, and 90° (head-on wind)]. It is found that the convective heat losses for both wind speed are higher than the losses obtained by no wind test. The highest heat losses are found for wind direction α is 60° with respect to receiver stand and lowest heat losses are found for wind direction α is 0° (side-on wind). The heat losses obtained for wind direction, α, is 30° condition are higher than the heat losses obtained for wind direction α is 0° (side-on wind) condition, while the heat losses obtained by wind direction α is 90° (head-on wind) condition are less than the heat losses obtained for wind direction, α, is 60° condition.
PAPER REVISED: 2015-09-29
PAPER ACCEPTED: 2015-09-29
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  1. Clausing, A.M., An analysis of convective losses from cavity solar central receivers, Solar Energy, 27 (1981), pp. 295-300.
  2. Harris, J.A., Lenz, T.G., Thermal performance of concentrator/ cavity receiver systems, Solar Energy, 34 (1985), pp. 135-142.
  3. Taumoefolau, T., Paitoonsurikarn, S., Hughe, G., Experimental investigation of natural convection heat loss from solar concentrator cavity receiver, J. Solar Energy Eng., 126 (2004), pp. 801-807.
  4. Leibfried, U., Ortjohann, J., Convective heat loss from upward and downward-facing cavity solar receivers: measurements and calculations, J. Solar Energy Eng., 117 (1995), pp. 75-84.
  5. Stine, W.B., McDonald, C.G., Cavity receiver heat loss measurements, Proceeding of Int. Solar Energy Society World Congress, Kobe, Japan, 1989, pp. 1318-1322.
  6. Jilte, R.D., Kedare, S.B., Nayak, J.K., Natural convection & radiation heat loss from open cavities of different shapes & sizes used with dish concentrator, Mech. Eng. Reasearch, 3 (2013), pp. 25-43.
  7. Koenig, A.A., Marvin, M., Convection heat loss sensitivity in open cavity solar receivers, Final report, DOE Contract No: EG77-C-04-3985, Department of Energy, Oak Ridge, Tennessee, 1981.
  8. Prakash, M., Kedare, S.B., Nayak, J.K., Determination of stagnation and convective zones in a solar cavity receiver, Int. J. Therm. Sci., 49 (2010), pp. 680-691.
  9. Clausing, A.M., Convective losses from cavity solar receivers- comparisons between analytical predictions and experimental results, J. Solar Energy Eng., 105 (1983), pp. 29-33.
  10. Quere, P., Penot, F., Mirenayat, M., Experimental study of heat loss through natural convection from an isothermal cubic open cavity, Sandia Laboratory Report SAND81-8014, Livermore, California, 1981.
  11. Sendhil Kumar, N., Reddy, K.S., Comparison of receivers for solar dish collector system. Energy Conver. Manag., 49 (2008), pp. 812-819.
  12. Prakash, M., Kedare, S.B., Nayak, J.K., Investigations on heat losses from a solar cavity receiver. Solar Energy 83 (2009), pp. 157-170.
  13. Ma, R. Y, Wind effects on convective heat loss from a cavity receiver for a parabolic concentrating solar collector, Sandia National Laboratories Report SAND92-7293, 1993.
  14. Paitoonsurikarn, S., Lovegrove, K., Numerical investigation of natural convection loss in cavity-type solar receivers, Proceeding of Solar 2002, ANZSES Annual Conference, Newcastle, Australia 2002.
  15. Prakash, M., Kedare, S.B., Nayak, J.K., Numerical study of natural convection loss from opens cavities. Int. J. Therm. Sci., 51 (2012), pp. 23-30.
  16. Hess, C.F., Henze, R.H., Experimental investigations of natural convection losses from open cavities, J. Heat Trans., 106 (1984), pp. 333-338.
  17. Chan, Y.L., Tien, C.L., A numerical study of two-dimensional laminar natural convection in shallow open cavities, Int. J. Heat Mass Trans., 28 (1985), pp. 603-612.
  18. James, A., Terry, G., Thermal performance of solar concentrator cavity receiver systems, Solar Energy, 34 (1985), pp. 135-142.
  19. Reddy, K.S., Kumar, K.R., Satyanarayana, G.V., Numerical investigation of energy efficient receiver for solar parabolic trough concentrator, J. Heat Trans., 29 (2008), pp. 961-972.
  20. Paitoonsurikarn, S., Lovegrove, K., On the study of convection loss from open cavity receivers in solar paraboloidal dish application, in: Proceedings of Solar 2003, ANZSES Annual Conference, Melbourne, Australia, 2003.
  21. McDonald, C.G., Heat Loss from an Open Cavity, Sandia National Laboratories Report SAND95-2939, 1995.
  22. Sendhil Kumar, N., Reddy, K.S., Numerical investigation of natural convection heat loss in modified cavity receiver for fuzzy focal solar dish concentrator, Solar Energy, 81 (2007), pp. 846-855.
  23. Sendhil Kumar, N., Reddy, K.S., Study of combined natural convection and surface radiation heat transfer in a Modified cavity receiver of solar parabolic dish, Int. J. Therm. Sci., 47 (2008), pp. 1647-1657.
  24. Wu, S.Y., Guan, J.Y., Xiao, L., Shen, Z.G., Xu, L.H., Experimental investigation on heat loss of a fully open cylindrical cavity with different boundary conditions, Exp. Therm. Fluid Sci., 45 (2013), pp. 92-101.

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