Measurement of the Basic Properties of Ternary Eutectic Chloride Salts Used as High Temperature Heat Transfer Fluids and Thermal Storage Media

2016 ◽  
Author(s):  
Ghazal Dehghani ◽  
Xiankun Xu ◽  
Peiwen Li
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
High Temperature ◽  
High Temperatures ◽  
Ternary Eutectic ◽  
Heat Transfer Fluid ◽  
Heat Of Fusion ◽  
Gravimetric Analysis ◽  
Salt Mixtures ◽  
Temperature Heat

Concentrated solar power (CSP) technologies tend to work at more and more high temperatures, which correspondingly need a high temperature heat transfer fluid (HTF) to transmit the heat from solar concentrator to power plant. The objective of this work is to study heat capacities of a HTF which can work at upper limit temperature of around 850 °C. The ideal HTF should have low melting temperature and be thermally stable at high temperatures. High specific heat capacity is also favorable. The eutectic ternary salt mixtures studied in this work are formed by NaCl, KCl and ZnCl2. The heat capacity, heat of fusion, and melting temperatures of three salt mixtures were measured by using Differential Scanning Calorimetry (DSC)/Thermal Gravimetric Analysis (TGA) simultaneously. The accuracy of the measurements was validated by measuring three metals, Indium, Tin, and Zinc, which have standard reference data. Each of the three eutectic mixtures by NaCl-KCl-ZnCl2 ternary system had 10 to 11 samples tested for heat of fusion, the melting point, and heat capacity. Mixing rule from literature was used to estimate the heat capacity of the new HTF, which showed very good agreement to experimental data.

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.

Calculation and Optimization of Molten Salt for Solar High Temperature Heat Storage

2012 ◽  
Vol 178-181 ◽  
pp. 62-65
Author(s):  
Qiu Hui Yan ◽  
Hong Na Wang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Energy Storage ◽  
Sodium Chloride ◽  
Potassium Chloride ◽  
Heat Storage ◽  
Chloride Salt ◽  
Salt Mixtures ◽  
Temperature Heat ◽  
Carbonate Salt

The development of energy saving technologies is very actual issue of present day. One of perspective directions in developing these technologies is the thermal energy storage in various industry branches. To meet the requirement of high temperature of solar heat transfer and thermal storage, this paper calculated several sets of data for lots of pure salts and salt mixtures. The results show that, comparing with the ternary carbonate salt (potassium carbonate (0.7) - sodium carbonate (0.1) -potassium chloride (or sodium chloride)), the ternary chloride salt (potassium chloride (0.037) - calcium chloride (0.5) - sodium chloride) is more perspective.

Experimental Investigation to the Properties of Eutectic Salts by NaCl-KCl-ZnCl2 for Application as High Temperature Heat Transfer Fluids

2014 ◽  
Author(s):  
Kai Wang ◽  
Edgar Molina ◽  
Ghazal Dehghani ◽  
Ben Xu ◽  
Peiwen Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Melting Point ◽  
Vapor Pressure ◽  
Mole Fraction ◽  
Heat Transfer Fluid ◽  
Test Facility ◽  
Vapor Pressures ◽  
Heat Transfer Fluids ◽  
Temperature Heat

A group of eutectic ternary halide salts were surveyed and studied for the objective of developing a high temperature heat transfer fluid with a freezing point below 250°C and a low vapor pressure, below 1.0 atm, at temperatures up to 800°C. The studied salts include: 1) NaCl-KCl-ZnCl2 with a mole fractions of 18.6%-21.9%-59.5% and a melting point of tm=213°C; 2) NaCl-KCl-ZnCl2 with a mole fraction of 13.4%-33.7%-52.9% and a melting point of tm=204°C; and 3) NaCl-KCl-ZnCl2 with mole fraction of 13.8%-41.9%-44.3% and a melting point of tm=229 °C. Vapor pressures of these salts at different temperatures were experimentally obtained using an in-house developed test facility. The results show that vapor pressures of all the three eutectic molten salts are below 1.0 atm at a temperature of 800 °C. The salt of ZnCl2-KCl-NaCl in mole faction of 44.3%-41.9%-13.8% has lowest vapor pressure which is only about 1.0 atm even at a temperature of 900 °C. Viscosities of these salts were measured in the temperature range from after melting to 850°C. At low temperatures near their melting points of the salts, the viscosities are about 16 × 10−3Pa s, while at high temperatures above 700°C the viscosities are around 4 × 10−3Pa s, which is satisfactorily low to serve as heat transfer fluid for circulation in a CSP system. Both the vapor pressure and the viscosities of the studied three eutectic salts demonstrated satisfaction to serve as high temperature heat transfer fluids. Other thermal and transport properties of these salts are expected to be reported in the future for screening out a satisfactory high temperature heat transfer fluid.

High Temperature Thermochemical Energy Storage Using Packed Beds

2016 ◽  
Author(s):  
Qasim A. Ranjha ◽  
Nasser Vahedi ◽  
Alparslan Oztekin
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Energy Storage ◽  
Solar Energy ◽  
Latent Heat ◽  
High Temperatures ◽  
Heat Storage ◽  
Three Dimensional ◽  
Heat Transfer Fluid ◽  
Latent Heat Storage

Thermal energy storage units are vital for development of the efficient solar power generation systems due to fluctuating nature of daily and seasonal solar radiations. Two available efficient and practical options to store and release solar energy at high temperatures are latent heat storage and thermochemical storage. Latent heat storage can operate only at single phase change temperature. This problem can be avoided by some of the thermochemical storage systems in which solar energy can be stored and released over a range of high temperature by endothermic and exothermic reactions. One such reaction system is reversible reaction involving dehydration of Ca(OH)2 and hydration of CaO. This system is considered in the present study to model a circular fixed bed reactor for storage and release of heat at high temperatures. Air is used as heat transfer fluid (HTF) flowing in an annular shell outside the bed for charging and discharging the bed. The bed is filled with CaO/Ca(OH)2 powders with particles diameter of the order 5μm. Three dimensional transient model has been developed and simulations are performed using finite elements based COMSOL Multiphysics. Conservation of mass and energy equations, coupled with reaction kinetics equations, are solved in the three dimensional porous bed and the heat transfer fluid channel. Parametric study is performed by varying HTF parameters, bed dimensions and process conditions. The results are verified through a qualitative comparison with experimental and simulation results in the literature for similar geometric configurations.

scholarly journals ISSUES OF USING HIGH-TEMPERATURE HEAT-TRANSFER FLUID WITH IMPROVED THERMOPHYSICAL PROPERTIES IN FIRE-TUBE BOILERS

2021 ◽  
pp. 038-041
Author(s):  
E. N. Slobodina ◽  
◽  
A. G. Mikhailov ◽  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Thermophysical Properties ◽  
Heat Transfer Fluid ◽  
Temperature Heat ◽  
In Fire

В работе представлены особенности использования высокотемпературных теплоносителей с наночастицами в котлах, классификация методов получения наножидкостей, описание основных теплофизические свойства и коэффициенты теплопроводности материалов, используемых для получения наножидкостей. Рассмотрены механизмы теплопереноса в наножидкостях, определяющих эффективность работы котла. Полученные данные являются предпосылками для создания эффективного жаротрубного котла с высокотемпературным теплоносителем.

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