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Features of Convective Heat-Exchange in Flat-Plate Solar Water-Heating Collectors

  • SOLAR POWER PLANTS AND THEIR APPLICATION
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Abstract—

Low-potential solar plants, including flat-plate water-heating collectors (FSWHC), are complex systems in terms of heat engineering. A problem in the development of both stationary and non-stationary heat engineering FSWHC models is to specify convective heat exchange in SWHC channels. This paper considers the features and conditions of convective heat transfer in SWHC channels to water. It is shown that the water flow hydrodynamic and thermal stabilization sections in FSWHCs and at potential speeds of their heat carriers reach only 10 to 13 cm in length and the convective heat exchange in SWHCs can be calculated at a constant value of Nu. It is found that the differences in temperature between the walls of a SWHC channel and between the wall and the liquid will not exceed 10 and 5°C, respectively. These conditions make mixed free and forced convection in SWHC channels possible. Since the heat mainly comes from the upper walls of the channel, this determines the need for pilot studies to determine the distribution of temperature on the walls and in the liquid along the channel length and the difference in temperature between them. The heat exchange in SWHC channels can be heavily affected by free convection. An important issue when elaborating design models of heat exchange in SWHCs is the possibility of applying the convective heat exchange formulas used for plates to the walls of SWHC channels.

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ACKNOWLEDGMENTS

We thank the reviewers for a high-quality discussion of the paper.

Funding

The work was financially supported by the Ministry of Innovation Development of the Republic of Uzbekistan, research project no. OT-F3-14.

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Authors and Affiliations

  1. Scientific and Technical Center with Design Bureaus and Experimental Production, Academy of Sciences of the Republic of Uzbekistan, 100125, Tashkent, Uzbekistan

    Sh. I. Klychev, S. A. Bakhramov & D. E. Kadyrgulov

  2. Federal Scientific Agroengineering Center VIM, 109456, Moscow, Russia

    V. V. Kharchenko

  3. Bukhara Branch of the Tashkent Irrigation Institute, 100365, Bukhara, Uzbekistan

    Kh. Nuriddinov

Authors
  1. Sh. I. Klychev
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  2. S. A. Bakhramov
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  3. V. V. Kharchenko
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  4. Kh. Nuriddinov
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  5. D. E. Kadyrgulov
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Corresponding author

Correspondence to Sh. I. Klychev.

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Published for discussion

Translated by S. Kuznetsov

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Klychev, S.I., Bakhramov, S.A., Kharchenko, V.V. et al. Features of Convective Heat-Exchange in Flat-Plate Solar Water-Heating Collectors. Appl. Sol. Energy 55, 321–326 (2019). https://doi.org/10.3103/S0003701X19050062

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  • DOI: https://doi.org/10.3103/S0003701X19050062

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