Contents lists available at ScienceDirect Solar Energy Materials & Solar Cells journal homepage: www.elsevier.com/locate/solmat Characterization of different sugar alcohols as phase change materials for thermal energy storage applications E. Palomo del Barrio a , A. Godin b, ⁎ , M. Duquesne c , J. Daranlot d , J. Jolly d , W. Alshaer e , T. Kouadio b , A. Sommier b a Université de Bordeaux, I2M UMR 5295, F-33400 Talence, France b CNRS, I2M UMR 5295, F-33400 Talence, France c Institut National Polytechnique de Bordeaux, I2M UMR 5295, F-33400 Talence, France d SOLVAY, Laboratoire du Futur, 178 Av du Dr Schweitzer, 33608 Pessac, France e Mechanical Engineering Department, Benha 13512, Egypt ARTICLE INFO Keywords: Thermal energy storage PCM Sugar alcohols Characterization ABSTRACT Sugar alcohols (SA) are attractive phase change materials (PCM) for thermal energy storage applications at low- to-medium temperatures (70–180 °C). Five pure sugar alcohols (xylitol, adonitol, L-arabitol, erythritol, D- mannitol) and three eutectic blends (eythritol/xylitol, L-arabitol/erythritol, L-arabitol/xylitol) are investigated in this paper. Experimental characterization of such materials as PCMs is provided. This encompasses the measurement of their melting point and latent heat of fusion, as well as the experimental determination of all key physical properties (specific heat, thermal conductivity, thermal diffusivity, density, viscosity) as a function of the temperature. The performances of the studied materials are compared to those of most currently used PCMs (paraffin waxes, salt hydrates etc.) in the field of thermal energy storage. The most significant applications, including solar seasonal energy storage, are also discussed. 1. Introduction Sugar alcohols (SA), also called hydrogenated carbohydrates and polyols, belong to the family of low molecular weight carbohydrates. More than 900 SA are listed in the dictionary of carbohydrates edited by Collins [1]. However, only few of them are commonly used and produced at a large scale. The most commonly used SA are sorbitol, mannitol, xylitol, lactitol, maltitol, erythritol and isomalt. Some SA are found naturally in various fruits and vegetables. However, most of them are produced by chemical reduction of carbohydrates. The production of polyurethane is the largest and the oldest industrial application of polyols, with a market which is nowadays mature. SA are also widely used in the food industry, mainly as sugar replacers, and in the pharmaceutical sector. Detailed information about SA (production, applications and market) can be found on the web-site of the European Association of Polyol Producers (www.polyols-eu.com)(Tables 1 and 2). The use of SA as PCMs for thermal energy storage applications was described for the first time in the patents of Guex et al. [2] and Hormansdorfer [3]. They noted that some of the SA have volumetric latent heat as much as twice that of commonly used PCMs (i.e. paraffin waxes). Besides, SA are of natural origin, they are non-flammable, non- toxic and non-corrosive, and they have affordable cost. Since then, different SA have been considered and studied for storage applications at medium temperatures (100–200 °C). Among them, erythritol has received the most attention so far and has been used in various applications such as waste-heat transportation [4,5], solar cookers [6,7], absorption chillers [8], and as an automotive coolant waste heat storage system [9]. It is characterized by a melting temperature around 118 °C and relatively large latent heat of 340 J/g (see Table 3). For applications at higher temperatures, other SA such as D-mannitol, dulcitol, mio-inositol and their mixtures have also been investigated [10–15] and envisaged for thermal energy storage in industrial applications. More recently, SA have been considered as candidates for latent heat storage applications at temperatures below 100 °C (e.g.: solar heating and DHW, district heating). New SA-based mixtures with a melting point in the temperature range from 75 °C to 100 °C and relatively high latent heat (170–260 J/g) have been proposed by Hidaka et al. [16], Nakada et al. [17] and Diarce et al. [18]. In the recent European project SAM.SSA (FP7 2012–2015; www.samssa.eu/) sugar alcohol-based materials for solar thermal seasonal storage http://dx.doi.org/10.1016/j.solmat.2016.10.009 Received 7 August 2016; Received in revised form 26 September 2016; Accepted 5 October 2016 ⁎ Corresponding author. E-mail address: alexandre.godin@u-bordeaux.fr (A. Godin). Solar Energy Materials & Solar Cells 159 (2017) 560–569 0927-0248/ © 2016 Elsevier B.V. All rights reserved. crossmark