Revival of Halide Salts as High-Temperature Heat-Transfer Media: Key Technical and Scientific Issues

2019 ◽  
Vol 3 (35) ◽  
pp. 441-451 ◽  
Author(s):  
David F. Williams
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Temperature Heat ◽  
Halide Salts

Thermal and Transport Properties of NaCl–KCl–ZnCl2 Eutectic Salts for New Generation High-Temperature Heat-Transfer Fluids

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Peiwen Li ◽  
Edgar Molina ◽  
Kai Wang ◽  
Xiankun Xu ◽  
Ghazal Dehghani ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Transport Properties ◽  
Thermal Power ◽  
Engineering Application ◽  
Heat Transfer Fluid ◽  
Heat Of Fusion ◽  
Temperature Heat ◽  
New Generation ◽  
Halide Salts

Three eutectic salts from a system of halide salts NaCl–KCl–ZnCl2 were chosen for detailed study of thermal and transport properties with the objective of developing a next generation high-temperature heat-transfer fluid (HTF) for concentrated solar thermal power (CSP) technology. The acceptable range of the working temperatures for the HTF is from below 250 °C to at least 800 °C. The tested properties are presented here for the three candidate eutectic salts, including melting point, heat of fusion, heat capacity, vapor pressure, viscosity, density, and thermal conductivity. Data-fitted equations are provided for all the measured properties for convenience in engineering application. It is concluded that the three eutectic salts can satisfy the needs for a high-temperature HTF and thus are recommended as a new generation high-temperature HTF.

Effect of Absorptive Coating of the Hot Fluid Passage of a Heat Exchanger Employing Exergy-Optimized Pin Fins in High Temperature Applications

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Nwosu P. Nwachukwu ◽  
Samuel O. Onyegegbu
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Simple Relation ◽  
Base Temperature ◽  
Minimum Entropy ◽  
Pin Fin ◽  
Temperature Heat ◽  
Pin Fins ◽  
Minimum Entropy Generation ◽  
Fluid Parameters

An expression for the optimum pin fin dimension is derived on exergy basis for a high temperature exchanger employing pin fins. The present result differs from that obtained by Poulikakos and Bejan (1982, “Fin Geometry for Minimum Entropy Generation in Forced Convection,” ASME J. Heat Transfer, 104, pp. 616–623) for a low temperature heat recovery application. Also, a simple relation is established between the amounts the base temperature of the optimized pin fin is raised for a range of absorptive coating values. Employing this relation, if the absorptivity of the coating, the plate emissivity, the number of protruding fins, and some area and fluid parameters are known, the corresponding value for the base temperature of the fin is immediately obtained. The analysis shows that the thermal performance of the exchanger improves substantially with a high absorptivity coating hence can be seen as a heat transfer enhancement feature of the exchanger operating with radiation dominance.

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