Experimental investigation of thermal characteristics of a mortar with or without a micro-encapsulated phase change material Annabelle Joulin a, b,1 , Laurent Zalewski a, b, * , Stéphane Lassue a, b, 2 , Hassane Naji a, b, 3 a Laboratoire de Génie Civil et géo-Environnement (LGCgE), Université Lille Nord de France, F-59000 Lille, France b UArtois, LGCgE, Technoparc Futura, F-62400 Béthune, France highlights  Achievement of an experimental investigation of a composite phase change material (PCM).  Use of a thermophysical approach to achieve the main thermal characteristics.  Improvement of the stored and released energy via PCM integration.  Implementation of a composite PCM with potential applications in buildings. article info Article history: Received 9 July 2013 Accepted 17 January 2014 Available online 10 February 2014 Keywords: Micro-encapsulated phase change materials Cement mortar Heat flux measurement Latent heat Apparent specific heat abstract This article deals with a method of thermal characterization of buildings materials including micro- encapsulated phase change materials (PCMs) incorporated into cement-mortars from simultaneous heat flux and temperature measurements. The thermal behavior of the sample and the conventional mortar are compared. The main goal of this method is to determine the latent heat and the temperature of the studied PCM to provide reference solutions allowing validating numerical simulations. In this work, the thermophysical characterization carried out here yields the experimental determination of conductivities, heat capacities and the latent heat of solid/liquid phase change as well as the phase change temperature of micro-encapsulated PCM embedded into cement mortars and common mortars in their implementation state. From the obtained results, it can be concluded that the considered composite PCM has potential thermal energy storage purpose in buildings. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Since several decades, the thermal regulation requirements for buildings have increased significantly in order to reduce fossil en- ergy use. They have brought in some changes in the envelope and systems to an efficient level allowing the conception of low energy use buildings. These buildings, often fitted with an internal insu- lation, have low thermal mass and may be subject to large tem- perature fluctuations [1]. It is generally accepted that thermal mass contributes to energy efficiency in buildings, playing a stabilizing role and allowing comfortable ambient temperatures reducing the requirement for air conditioning in summer and reducing heating fuel consumption in winter. The use of phase change materials (PCMs) can be very helpful on challenging sites where otherwise the provision of thermal mass would be difficult. To overcome this low thermal mass issue, PCMs have enjoyed renewed popularity as they enable to absorb large energy amounts in a tiny volume [2e4]. They are considered as a solution for the lack of inertia with the additional advantage to store energy (in- takes) at times and to release it at some useful point [5e7]. Several types of materials (hydrated salts [8,9], organic and inorganic PCM into polymers, microencapsulated PCM [3,10,11], shape stabilized PCM [12,13]) with a large panel of melting temperatures [14], in extremely various containers have been studied recently [15]. However, the behavior of these materials is complex, with ther- mophysical properties difficult to measure. Moreover, they are prone to supercooling and hysteresis phenomenon [8,16,17]. Their * Corresponding author. UArtois, LGCgE, Technoparc Futura, F-62400 Béthune, France. Tel.: þ33 321637153. E-mail addresses: annabelle.joulin@univ-artois.fr (A. Joulin), laurent.zalewski@ univ-artois.fr (L. Zalewski), stephane.lassue@univ-artois.fr (S. Lassue), hassane. naji@univ-artois.fr (H. Naji). 1 Tel.: þ33 321632356. 2 Tel.: þ33 321637154. 3 Tel.: þ33 321637141. Contents lists available at ScienceDirect Applied Thermal Engineering journal homepage: www.elsevier.com/locate/apthermeng http://dx.doi.org/10.1016/j.applthermaleng.2014.01.027 1359-4311/Ó 2014 Elsevier Ltd. All rights reserved. Applied Thermal Engineering 66 (2014) 171e180