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Mixed convective flow and thermal stratification in hot water storage tanks during discharging mode

  • Solar Power Plants and Their Application
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Abstract

An analysis of transient, two dimensional, mixed convection and thermal stratification in cylindrical hot water storage tanks is presented. The governing equations together with inflow and outflow boundary conditions are written for laminar mixed convection flow using a finite volume based computational code in the dynamic discharging mode based on Boussinesq approximations and conjugate heat transfer. The equations are solved numerically and the results are obtained for aspect ratios of the tanks ranging from 1 to 4 in the Richardson number range of 105 to 108 using a finite volume based computational code. The dynamic discharging mode is considered using a conjugate heat transfer model. The transient temperature profiles in the bulk fluid reveal reduced mixing at higher Richardson numbers during discharging process. The system performance in the dynamic mode of operation is defined by a Mix Number and discharging efficiency parameter. Mixing at the bottom of the tank due to inflow of low temperature water from the load is found to have significant influence on the storage efficiency. The discharging efficiency decreases with Fourier number due to increased thermal degradation with time.

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References

  1. Jordan, U. and Furbo, S., Thermal Stratification in Small Solar Domestic Stage Tanks Caused by Draw-offs, Solar Energy, 2005, vol. 78, no. 2, pp. 291–300.

    Article  Google Scholar 

  2. Rosen, M.A., The Exergy of Stratified Thermal Energy Storages, Solar Energy, 2001, vol. 71, no. 3, pp. 173–185.

    Article  Google Scholar 

  3. Nelson, J.E.B., Balakrishnan, A.R., and Srinivasa, M.S., Experiments on Stratified Chilled Water Tanks, Int. J. Refrigeration, 1999, vol. 22, pp. 216–234.

    Article  Google Scholar 

  4. Nelson, J.E.B., Balakrishnan, A.R., and Srinivasa, M.S., Parametric Studies on Thermally Stratified Chilled Water Storage Systems, Appl. Thermal Eng., 1999, vol. 19. pp. 85–115.

    Article  Google Scholar 

  5. Spall, E.R., A Numerical Study of Transient Mixed Convection in Cylindrical Storage Tanks, Int. J. Heat Mass Transfer, 1998, vol. 41, no. 3, pp. 2003–2011.

    Article  MATH  Google Scholar 

  6. Hahne, E. and Chen, Y., Numerical Study of Flow and Heat Transfer Characteristics in Hot Water Stores, Solar Energy, 1998, vol. 64, nos. 1-3, pp. 9–18.

    Article  Google Scholar 

  7. Homan, K.O. and Soo, S.L., Model of Transient Stratified Flow into Chilled-Water Storage Tank, Int. J. Heat Mass Transfer, 1997, vol. 40, no. 18, pp. 4367–4377.

    Article  Google Scholar 

  8. Ghaddar, N.K. and Al-Maarafie, M., Study of Charging of Stratified Storage Tanks with Finite Wall Thickness, Int. J. Energy Res., 1997, vol. 21, pp. 411–427.

    Article  Google Scholar 

  9. Stewart, W.E., Cai, L., and Sohn, C.W., Thermal Stratification of Chilled Water Slot Flows into Storage Tanks, ASHRAE Transactions, 1994, pp. 305–316.

  10. Davidson, J.H., Adams, D.A., and Miller, J.A., A Coefficient to Characterize Mixing in Solar Water Storage Tanks, J. Solar Energy Eng., 1994, vol. 116, pp. 94–99.

    Article  Google Scholar 

  11. Yoo, H. and Pak, E.T., Theoretical Model of Charging Process for Stratified Thermal Storage Tanks, Solar Energy, 1993, vol. 51, pp. 513–519.

    Article  Google Scholar 

  12. Zurigat, Y., Liche, P., and Ghajar, A., Influence of Inlet Geometry on Mixing in Thermocline Thermal Energy Storage, Int. J. Heat Mass Transfer, 1991, vol. 34, pp. 115–125.

    Article  Google Scholar 

  13. Gupta, S.K. and Jaluria, Y., An Experimental and Analytical Study of Thermal Stratification in an Enclosed Water Region due to Thermal Energy Discharge, Energy Convers. Mgmt., 1982, vol. 22, pp. 63–70.

    Article  Google Scholar 

  14. Patankar, S.V., Numerical Heat Transfer and Fluid Flow, Washington: Hemisphere Publ. Corp., 1980.

    MATH  Google Scholar 

  15. Fluent User’s Manual ver. 5.0, Sheffield: Fluent Europe Ltd., 1995.

  16. Lavan, Z. and Thompson, J., Experimental Study of Thermally Stratified Hot Water Storage Tanks, Solar Energy, 1977, vol. 19, pp. 519–524.

    Article  Google Scholar 

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Authors and Affiliations

  1. Department of Mechanical Engineering, Indian Institute of Technology, Madras, India

    N. Gopalakrishnan & S. Srinivasa Murthy

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  1. N. Gopalakrishnan
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  2. S. Srinivasa Murthy
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Gopalakrishnan, N., Srinivasa Murthy, S. Mixed convective flow and thermal stratification in hot water storage tanks during discharging mode. Appl. Sol. Energy 45, 254–261 (2009). https://doi.org/10.3103/S0003701X09040070

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  • DOI: https://doi.org/10.3103/S0003701X09040070

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