ESTIMATION OF HEAT LOSSES FOR THE TUBE HEAT RECEIVER OF THE SOLAR TROUGH MODULES
The one-dimensional mathematical model for the quantitative estimation of the heat losses from tube receiver system of the solar trough module was created. Based on this mathematical model the numerical algorithm was developed and numerical experiments were carried out. The studies were conducted for tube heat receiver which placed inside glass envelope as «tube-in-tube». Cases with atmosphere air in annular space and with various vacuum degree were described. Analysis for a unit tube without the glass envelope was carried out separately. A system of nonlinear algebraic equations, which consist basis of the mathematical model, was solved using fixed-point iteration method. Convergence of iterates was provided through initial guess, which were chosen as close to the real values. The thermophysical parameters depend on the temperature and pressure. It was considered in the created mathematical model. The calculation method for the heat flow through a gas layer was offered. The vacuum gas degree was taken into account in the method. As physical model for numerical analysis was chosen solar though module which studied experimentally. Data of the experiments were described in scientific literature. Numerical analyses were carried out for two cases – with heat flow from concentrator and without it. Comparison of numerical and experimental data show good agreement of results. Slight discrepancies were observed for glass temperature and for heat losses in the presence of wind. Analyses show that glass envelope is mandatory design element for heat receiver system of the solar though energy modules. If atmosphere air is used inside glass envelope than heat losses decreased twice, if deeper vacuum – in tree times. Ref. 13, fig. 3.
2. Knysh L.I. Metod uchyota teplovoj provodimosti absor¬bera v ploskom solnechnom kollektore. [The method of ac-counting of heat conductivity of absorber the flat solar collec¬tor]. Vidnovluvana energetika. 2014. No. 2(37). Pp. 38-42. [in Rus-sian].
3. Knysh L.I., Goman O.G. Osobennosti modelirovaniya energoperenosa v sisteme priyoma tepla solnechnoj parabo-loczilindricheskoj stanczii. [Modeling features of energy-mass transfer in the heat receiver system of the solar parabolic cylindri-cal plant]. Visnyk Khersonskoho natsionalnoho tekhnichnoho universytetu. 2016. No. 3(58). Pp. 352-356. [in Russian].
4. Koshmarov Yu.A., Ryzhov Yu.A. Prikladnaya dinamika razrezhennogo gaza. [Applied rarefied gas dynamics]. Moscow. Mashinostroenie. 1977. 184 p. [in Russian].
5. Kudria S.A., Pepelov A.V. Vykorystannia vid-novliuvanoi enerhii: dosvid rozvynutykh krain. [The use of re-newable energy: the experience of developed countries]. Kiev. UNIDO. URL: http://www.reee.org.ua/download/trainings/%0%A2%D0% 9C28.pdf . [in Ukrainian].
6. Mikheev M.A., Mikheeva I.M. Osnovy teploperedachi. [Heat Transfer Basics]. Moscow. Еnergiya. 1977. 344 p. [in Rus-sian].
7. Rieztsov V.F., Surzhyk T.V., Okhota O.O. Eksperymentalne doslidzhennia teploprovidnosti kompozitsiinykh materialiv kolektoriv soniachnoi enerhii. [Experimental study of thermal conductivity of composite materials of solar energy collectors]. Vidnovluvana energetika. 2016. No. 2(46). Pp. 41-44. [in Ukrainian].
8. Rieztsov V.F., Surzhyk T.V., Shchokina V.A. Mozhlyvi prychyny formuvannia neodnoridnykh struktur pry heliosushtsi volohovmisnykh seredovyshch. [Possible reasons for the formation of inhomogeneous structures during the solar drying of moisture-containing media]. Vidnovluvana energetika. 2015. No. 1(40). Pp. 28-31. [in Ukrainian].
9. Surzhyk T.V. Doslidzhennia materialu absorbera soniachnoho kolektora z polimernykh kompozytsiinykh material-iv. [Investigation of the material of a solar collector absorber made of polymer composite materials]. Vidnovluvana energetika. 2015. No. 4. Pp. 28-31. [in Ukrainian].
10. Hachicha A.A., Bashria A.A. Yousef Zafar Said, Ivette Rodriguez. A review study on the modeling of high-temperature
solar thermal collector systems. Renewable and Sustainable En-ergy Reviews. 2019. V. 112. Pp. 280-298. [in English].
11. Cheng Z.D., He Y.L., Xiao J., Tao Y.B., Xu R.J. Thre¬e-dimensional numerical study of heat transfer characteristics in the receiver tube of parabolic trough solar collector. International Journal of Heat and Mass Transfer. 2010. V. 37. Pp. 782-787. [in English].
12. Theodore L., Bergman and other. Fundamentals of Heat and Mass Transfer. John Wiley & Sons. 2007. 1051 p. [in English].
13. Dudley V., Kolb G., Sloan M., Kearney D. SEGS LS2 Solar Collector Test Results. Report of Sandia National Laborat¬ories. USA. 1994. 140 р. [in English].
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