Liquid Metals as Efficient High-Temperature Heat-Transport Fluids

Liquid metals have received growing attention as a potential replacement for more conventional heat transfer fluids in concentrated solar power (CSP) systems. Owing to liquid metals high thermal conductivity, an increase in solar receiver efficiency as well as higher serviceable temperatures could enable more advanced power cycles to be integrated to the CSP system. Recently, CSIRO carried out research on a solar air turbine system which includes a demonstration of a high-temperature pressurized air receiver combined with high-temperature thermal storage. Since the operation temperature of a solar air turbine system is much higher than that of conventional CSP systems, Lead-Bismuth Eutectic (LBE) alloy was chosen for its favorable high temperature heat transport properties and relative ease of storage. The heat test apparatus consisted of a LBE-air heat exchanger, storage tanks with internal heating elements and a pumping system developed by CSIRO. During the test, approximately 1,000 kg of LBE was successfully pumped while capturing and storing approximately 35MJ of solar energy. The test successfully transferred heat from the solar air receiver to the LBE, with the temperature of stored LBE reaching over 770 °C. This paper will present the concept of the test system, design of its components, procedures and results of the test, and also lessons learnt.

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Lead-Bismuth Eutectic as a High Temperature Heat-Transport Fluid for Thermal Solar Power

Volume 1: Combined Energy Cycles, CHP, CCHP, and Smart Grids; Concentrating Solar Power, Solar Thermochemistry and Thermal Energy Storage; Geothermal, Ocean, and Emerging Energy Technologies; Hydrogen Energy Technologies; Low/Zero Emission Power Plants and Carbon Sequestration; Photovoltaics; Wind Energy Systems and Technologies ◽

10.1115/es2014-6528 ◽

2014 ◽

Author(s):

D. Frazer ◽

C. Cionea ◽

M. Popovic ◽

Y. Aussat ◽

A. J. Gubser ◽

...

Keyword(s):

High Temperature ◽

Heat Transport ◽

Solar Power ◽

Liquid Metals ◽

Operating Temperature ◽

Structural Steels ◽

Nuclear Industry ◽

Temperature Heat ◽

Lead Bismuth Eutectic ◽

Transport Fluid

In order to increase the thermal efficiency and produce process heat for hydrogen production, the operating temperature of the heat-transfer fluid in thermal solar plants needs to increase, but to increase the operating temperature, new heat-transport liquids need to be evaluated. Liquid metals have been proposed as heat-transport fluids because of the large temperature ranges over which they remain liquid. One of the most studied liquid metals for non-solar applications has been lead-bismuth eutectic alloy (LBE), for the nuclear industry. The main challenge with using LBE as a coolant is that the major constituents of structural steels have high solubility in LBE. In this work, the challenges of using LBE as a high temperature heat-transport fluid are discussed, as well as initial results of high-temperature static corrosion tests of structural steels to evaluate their potential use in a thermal solar power plant.

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Very-Low-Temperature Heat Transport of High-Temperature Superconductors

Peking University-World Scientific Advanced Physics Series - Superconductivity Centennial ◽

10.1142/9789813273146_0012 ◽

2018 ◽

pp. 157-180

Author(s):

X. F. Sun

Keyword(s):

High Temperature ◽

Low Temperature ◽

Heat Transport ◽

High Temperature Superconductors ◽

Temperature Heat ◽

Very Low Temperature

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Assessment of Solar Power Tower Driven Ultra Supercritical Steam Cycles Applying Tubular Central Receivers With Varied Heat Transfer Media

ASME 2009 3rd International Conference on Energy Sustainability, Volume 2 ◽

10.1115/es2009-90476 ◽

2009 ◽

Author(s):

Cs. Singer ◽

R. Buck ◽

R. Pitz-Paal ◽

H. Mu¨ller-Steinhagen

Keyword(s):

Heat Transfer ◽

High Temperature ◽

Cost Reduction ◽

Power Plants ◽

Reduction Potential ◽

Solar Power ◽

Liquid Metals ◽

Specific Investment ◽

Temperature Heat ◽

Electricity Costs

In commercial power plant technology, the market introduction of ultra supercritical (USC) steam cycle power plants with steam parameters around 350bar and 720°C is the next development step. USC steam cycles are also proposed to decrease the levelized electricity costs of future solar power towers due to their highly efficient energy conversion. A 55% thermal efficiency with decreased specific investment costs is within the potential of USC steam cycles. The required process parameters can be achieved using nickel based alloys in the solar receiver, the tubing and other plant components. For solar tower applications, appropriate high temperature heat transfer media (HTM), high temperature heat exchangers and storage options are additionally required. Using the current development for molten salt power towers (Solar Tres) as a reference, several tower concepts with USC power plants were compared. The ECOSTAR methodology provided by [1] was applied for predicting the cost reduction potential and the annual performance of these power tower concepts applying tubular receivers with various HTM. The considered HTM include alkali nitrate salts, alkali chloride salts and liquid metals such as a Bi-Pb eutectic, tin or sodium. For the assessment, an analytical model of the heat transfer in a parametric 360° cylindrical, tubular central receiver was developed to examine the receiver characteristics for different geometries. The sensitivity of the specific cost assumptions for the levelized electricity costs (LEC) was evaluated for each concept variation. No detailed evaluation was done for the thermal storage, but comparable costs were assumed for all cases. The results indicate a significant cost reduction potential for the liquid metal HTM processes.

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