TY - GEN
T1 - Entropy Generation Minimization To Optimize Heat Transfer In CSP Technologies Using Molten Salt System NaCl/KCl/MgCl2 As Heat Transfer Fluids
AU - Haddad, Fouad
AU - Li, Peiwen
N1 - Publisher Copyright:
© 2021 by ASME.
PY - 2021
Y1 - 2021
N2 - In order to optimize the flow and heat transfer of solar collectors and heat exchangers that use molten salts NaCl-KCl-MgCl2 or KCl-MgCl2, entropy generation minimization principle is used as the criterion. Gnielinski correlation and Dittus-Bölter correlation for Nusselt number versus Reynolds number as well as Moody friction factor given by Petukhov were used for the calculation of heat transfer coefficient and pressure loss due to friction. The objective function, the entropy production of the heat transfer system, was expressed as the function of Reynolds number, Prandtl number, heating flux, pipe diameter, etc. The minimum entropy production could be found from the first order deviation of the entropy production versus Reynolds number. As a result of the analysis, the optimum Reynolds number was determined and thereby determined the optimum Nusselt number, convective heat transfer coefficient, friction factor, and tube diameter, which helps the selection of optimum flow velocities and diameter of fluid pipes. The analysis was conducted in the fluid temperature range of 550 oC to 700 oC which covers the operation temperature for supercritical CO2 cycles. Results from using different heat transfer correlations (Gnielinski correlation and Dittus-Bölter correlation) have been compared and some obvious deviations were identified. It indicates that the selection of heat transfer correlations can cause some deviation of the optimal parameters of Reynolds number and pipe diameter. From the researcher's experience and experimental studies to molten chloride salts heat transfer, Gnielinski correlation for heat transfer is favorably recommended.
AB - In order to optimize the flow and heat transfer of solar collectors and heat exchangers that use molten salts NaCl-KCl-MgCl2 or KCl-MgCl2, entropy generation minimization principle is used as the criterion. Gnielinski correlation and Dittus-Bölter correlation for Nusselt number versus Reynolds number as well as Moody friction factor given by Petukhov were used for the calculation of heat transfer coefficient and pressure loss due to friction. The objective function, the entropy production of the heat transfer system, was expressed as the function of Reynolds number, Prandtl number, heating flux, pipe diameter, etc. The minimum entropy production could be found from the first order deviation of the entropy production versus Reynolds number. As a result of the analysis, the optimum Reynolds number was determined and thereby determined the optimum Nusselt number, convective heat transfer coefficient, friction factor, and tube diameter, which helps the selection of optimum flow velocities and diameter of fluid pipes. The analysis was conducted in the fluid temperature range of 550 oC to 700 oC which covers the operation temperature for supercritical CO2 cycles. Results from using different heat transfer correlations (Gnielinski correlation and Dittus-Bölter correlation) have been compared and some obvious deviations were identified. It indicates that the selection of heat transfer correlations can cause some deviation of the optimal parameters of Reynolds number and pipe diameter. From the researcher's experience and experimental studies to molten chloride salts heat transfer, Gnielinski correlation for heat transfer is favorably recommended.
UR - http://www.scopus.com/inward/record.url?scp=85124414930&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85124414930&partnerID=8YFLogxK
U2 - 10.1115/IMECE2021-67195
DO - 10.1115/IMECE2021-67195
M3 - Conference contribution
AN - SCOPUS:85124414930
T3 - ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
BT - Heat Transfer and Thermal Engineering
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME 2021 International Mechanical Engineering Congress and Exposition, IMECE 2021
Y2 - 1 November 2021 through 5 November 2021
ER -