Experimental and numerical investigation of a phase change material: Thermal-energy storage and release Annabelle Joulin a,b,⇑ , Zohir Younsi c , Laurent Zalewski a,b , Stéphane Lassue a,b , Daniel R. Rousse d , Jean-Paul Cavrot e a Univ Lille Nord de France, F59000 Lille, France b UArtois, LGCgE, F-62400 Béthune Cedex, France c HEI, rue de Toul, 59000 Lille, France d Department of Applied Sciences – Université du Québec à Chicoutimi, 555, boulevard de l’Université, Chicoutimi QC, Canada G7H 2B1 e UCCS Artois, IUT de Béthune, BP819, 62408 Béthune Cedex, France article info Article history: Received 14 June 2010 Received in revised form 7 January 2011 Accepted 13 January 2011 Available online xxxx Keywords: Phase change material Energy storage Supercooling Enthalpy method Fluxmetric experiments abstract The application of phase change materials (PCMs) for solar thermal-energy storage capacities has received considerable attention in recent years due to their large storage capacity and isothermal nature of the stor- age process. This study deals with the comparison of numerical and experimental results for a PCM condi- tioned in a parallelepipedic polyefin envelope to be used in passive solar walls. The experimental results were obtained by use of a genuine set-up involving heat flux sensors and thermocouples mounted on two vertical aluminium exchanger plates squeezing the samples. Numerical predictions were obtained with a custom one-dimensional Fortran code and a two-dimensional use of Fluent. Both methods showed a very good agreement with experimental observations for the melting process (65%). However during solidification, both numerical codes failed to predict the phase change process accurately, the maximal relative error was as high as 57% (with an average of 8%). Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction An extensive amount of research of problems involving phase change solid–liquid (fusion or solidification) has been done in var- ious scientific and technological domains as well as for industrial applications [1], such as, metallurgy and petrochemical industries, glass and plastic companies, food industries, thermal control of spacecrafts, heat exchanger [2], water purification [3] and so on. These systems are used in order to store thermal energy for a per- iod while the supply is sufficient or cheaper, to be discharged when the supply becomes insufficient or expensive [4,5]. The high ther- mal storage capacity of a phase change material (PCM) can reduce energy consumption in buildings [6,7]. PCM can be used to absorb heat gains during daytime and release heat at night. They could also be used for cooling and ventilation application to reduce energy consumption in buildings during summer period [8,9]. Thermal-energy storage can be accomplished either by using sensible heat storage or latent heat storage. Sensible heat storage has been used for centuries by builders to store/release passive thermal energy. In general, a much larger volume of material is required to store the same amount of energy in comparison to la- tent heat storage [4,10,11]. The principle of the use of phase change materials (PCMs) is simple. As the temperature increases, the material changes phase from solid to liquid. Because the reaction is endothermic, the PCM absorbs heat. Similarly, when the temper- ature decreases, the material changes phase from liquid to solid, and the PCM releases heat [2]. Zalba et al. [12] carried out of the history review of thermal- energy storage with solid–liquid phase change materials in mate- rials selection, heat transfer and applications. A great number of organic, inorganic, polymeric and eutectic compounds have been used as phase change materials, such as polyethylene glycol (PEG) and their composites (PEG/SiO2 [13] and so on). In order to improve the thermal conductivity of these PCMs, Wang et al. [14,15] added b-Aluminium nitride and expanded graphite into the organic PCMs. Salt hydrates are popular phase change materi- als (PCMs) for thermal-energy storage because of their high value of latent heat. Many of these substances are prone to supercooling, which for normal applications is problematic as it prevents the release of the stored latent heat. In the present paper, a detailed study on the thermal storage capacity of a phase change material for energy conservation in buildings, and in particular in solar walls, is analyzed and discussed. 0306-2619/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.apenergy.2011.01.036 ⇑ Corresponding author at: Univ Lille Nord de France, F59000 Lille, France. Tel.: +33 321632356; fax: +33 321632366. E-mail address: annabelle.joulin@univ-artois.fr (A. Joulin). Applied Energy xxx (2011) xxx–xxx Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy Please cite this article in press as: Joulin A et al. Experimental and numerical investigation of a phase change material: Thermal-energy storage and release. Appl Energy (2011), doi:10.1016/j.apenergy.2011.01.036