Waste from metallurgic industry: A sustainable high-temperature thermal energy storage material for concentrated solar power

Nicolas Calvet, Guilhem Dejean, Lucía Unamunzaga, Xavier Py

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

23 Scopus citations

Abstract

The ambitious DOE SunShot cost target ($0.06/kWh) for concentrated solar power (CSP) requires innovative concepts in the collector, receiver, and power cycle subsystems, as well as in thermal energy storage (TES). For the TES, one innovative approach is to recycle waste from metallurgic industry, called slags, as low-cost hightemperature thermal energy storage material. The slags are all the non-metallic parts of cast iron which naturally rises up by lower density at the surface of the fusion in the furnace. Once cooled down some ceramic can be obtained mainly composed of oxides of calcium, silicon, iron, and aluminum. These ceramics are widely available in USA, about 120 sites in 32 States and are sold at a very low average price of $5.37/ton. The US production of iron and steel slag was estimated at 19.7 million tons in 2003 which guarantees a huge availability of material. In this paper, electric arc furnace (EAF) slags from steelmaking industry, also called "black slags", were characterized in the range of temperatures of concentrated solar power. The raw material is thermo-chemically stable up to 1100 °C and presents a low cost per unit thermal energy stored ($0.21/kWht for ΔT=100 °C) and a suitable heat capacity per unit volume of material (63 kWht/m3 for ΔT=100°C). These properties should enable the development of new TES systems that could achieve the TES targets of the SunShot (temperature above 600 °C, installed cost below $15/kWht, and heat capacity ≥25 kWht/m3). The detailed experimental results are presented in the paper. After its characterization, the material has been shaped in form of plates and thermally cycled in a TES system using hot-air as heat transfer fluid. Several cycles of charge and discharged were performed successfully and the concept was validated at laboratory scale. Apart from availability, low-cost, and promising thermal properties, the use of slag promotes the conservation of natural resources and is a noble solution to decrease the cost and to develop sustainable TES systems.

Original languageBritish English
Title of host publicationASME 2013 7th Int. Conf. on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology, ES 2013
DOIs
StatePublished - 2013
EventASME 2013 7th International Conference on Energy Sustainability, ES 2013 Collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology - Minneapolis, MN, United States
Duration: 14 Jul 201319 Jul 2013

Publication series

NameASME 2013 7th Int. Conf. on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology, ES 2013

Conference

ConferenceASME 2013 7th International Conference on Energy Sustainability, ES 2013 Collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology
Country/TerritoryUnited States
CityMinneapolis, MN
Period14/07/1319/07/13

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