Recycled Material for Sensible Heat Based Thermal Energy Storage to be Used in Concentrated Solar Thermal Power Plants

Abstract

Current technologies of concentrated solar power plants (CSP) are under extensive industrial development hut still suffer from lack of adapted thermal energy storage (TES) materials and systems. In the case of e.xtended storage (some hours), thousands of tonnes of materials are concerned leading to high investment cost, high energy and GHG contents and major conflicts of use. In this paper, recycled industrial ceramics made by vitrification of asbestos containing wastes (ACW) are studied as candidates to be used as sensible TES material. The material presents no hazard, no environmental impact, good thermophysicalproperties (/.= 1.4 W m~' K~': Cp = 1025 J kg'' K'': p= 3100 kg m~^) and at very low investment cost. Thanks to the vitrification process of the wastes, the obtained ceramics is very stable up to 1200 °C and can be directly manufactured with the desired shape. The vitrified ACW can be used as TES material for all kinds of the CSP processes (from medium up to high concentration levels) with properties in the same tange than other available materials but with lower cost and without conflict of use. The proposed approach leads also to sustainable TES allowing a pay back of the energy needed for the initial waste treatment. Eurthermore, this new use of the matter can enhance the waste treatment industry instead of landfill disposal.

Compatibility tests between Jarytherm® DBT synthetic oil and solid materials from wastes

“…Since alumina is a nearly pure crystal, the corresponding XRD figures show less noise than in the case of the other solid materials, especially in the case of the coal fly ashes. Crystalline structures already identified in precedent works [2], [6], [8] are found: Wollastonite and Ferrobustamite in Cofalit ® , Anorthite and Mullite in coal fly ashes. In the case of alumina, nearly all peaks correspond to aluminum oxide, and the others seem to correspond to impurities, like iron oxides.…”

“…Cofalit ® is a ceramic glass which comes from asbestos that has been melted and vitrified [2]. Coal Fly Ashes (CFA) come from coal power plants and can also be melted into inert solid materials [6].…”

“…The latter comprises a thermocline thermal energy storage tank filled with solid materials. Alumina, which is a natural aluminum oxide, Cofalit ® [6], which is vitrified asbestos, and fly ashes which are coal power plant wastes, are three solid materials chosen for this study. Compatibility tests were performed in order to evaluate the effects of the contact between the solid materials and the oil.…”

Thermal performance evaluation of bischofite at pilot plant scale

“…An important manner to reduce costs related to the TES materials is the usage of recycled materials, wastes and industrials by-products, which are known for their low cost. Moreover, these materials should have high availability and lack of conflict of use [1] due to the fact that a large range of material amount is needed for TES purposes, from few kilograms in domestic systems to thousands of tones in solar plants [2].…”

Thermal energy storage for CSP (Concentrating Solar Power)

“…This concerns asbestos-containing wastes (ACW) [8], fly ash (FA) [9,10] and bottom ash (BA), slags from metallurgy [11] and all other mineral-like industrial wastes [12].…”