Case Study Design and Application of Concrete Tiles Enhanced with Microencapsulated Phase-Change Material Javed Narain 1 ; Weihua Jin 2 ; Masoud Ghandehari 3 ; Evan Wilke 4 ; Nitin Shukla 5 ; Umberto Berardi 6 ; Tahar El-Korchi 7 ; and Steven Van Dessel 8 Abstract: Phase-change materials (PCMs) have a high heat of fusion compared to that of traditional material, and for this reason, they are able to store and release larger amounts of energy at their transition temperature. The inclusion of PCMs in buildings has attracted much interest worldwide because of their ability to reduce building energy demand and increase indoor comfort. This paper presents the development and test- ing results of a concrete tile system with microencapsulated PCMs. The concrete tiles were cast for use in a high-performance house built for the Solar Decathlon China 2013 competition. The paper shows that the addition of PCMs reduced the overall compressive and flexural strength prop- erties of the concrete. A more than 25% decrease in compressive strength was observed with the addition of 20% PCM per volume of concrete. However, a significant improvement in the thermal properties of the concrete tile PCMs was measured. The thermal energy storage capability of the PCM-enhanced concrete tiles was determined using the dynamic heat flowmeter apparatus method. It was demonstrated that a 3.8-cm-thick concrete tile with 13.5% PCM had a thermal storage capacity equivalent to a 5.9-cm-thick tile of regular concrete, a 155% increase in thermal storage capability. Finally, the results indicate that the use of PCM in concrete floor tiles can significantly improve their thermal behavior, espe- cially in lightweight buildings, while also keeping the concrete’s strength loss within an acceptable range. DOI: 10.1061/(ASCE)AE.1943- 5568.0000194. © 2015 American Society of Civil Engineers. Author keywords: Phase-change material; Concrete tile; Recycled glass; Building energy conservation; Energy storage; Latent heat; Solar Decathlon. Introduction Phase-change materials (PCMs) have been successfully used to increase the thermal energy storage capacity of buildings. In fact, buildings that incorporate PCMs can store isothermally large por- tions of the thermal energy provided by solar irradiation during the daytime and then release this energy during the night (Kenisarin and Mahkamov 2007; Konuklu and Paksoy 2009). Numerous reviews on the use of PCMs in buildings have been recently pub- lished (Baetens et al. 2010; Ascione et al. 2014; Cabeza et al. 2011; Sharma et al. 2009; Soares et al. 2013; Zhou et al. 2012; Zhu et al. 2009). There are generally two ways to include PCMs in buildings: (1) by introducing PCMs as a passive thermal storage system incorporated into building elements (Kuznik et al. 2011) or (2) by using them as independent storage units coupled to the building’s HVAC system (Lazaro et al. 2009). The direct integra- tion of PCMs into building products, such as plasterboard panels and ceramic tiles, has already resulted in several commercial prod- ucts now available on the market (Zhang et al. 2008; Xu et al. 2005; Hittle 2002). Concrete is considered a suitable matrix for the inclusion of PCM because of its low cost and good fireproofing properties. Ling and Poon (2013) provided a detailed overview of the various meth- odologies for incorporating PCMs into a concrete mixture: (1) immersion of porous concrete in melted liquid PCM, (2) impregna- tion of PCM in porous aggregates, or (3) direct mixing of encapsu- lated PCM in fresh concrete. Hawes et al. (1990) studied the effects of PCM temperature, con- crete temperature, immersion time, and PCM dilution during the preparation process on the properties of PCM-enhanced concrete. Bentz and Turpin (2007) specified potential applications of PCM- enhanced concrete by analyzing the calorimetry of PCM embedded in porous lightweight aggregates. Concrete with different PCMs in lightweight aggregates were tested. In addition, to improve heat absorption characteristics, freeze-thaw performance improvements of PCM-enhanced concrete systems were recently studied by Sakulich and Bentz (2012). When using the direct mixing method for including PCMs in concrete, the encapsulation ensured that none of the liquid PCM leaked into the concrete during melting. Cabeza et al. (2007) 1 Researcher, Dept. of Civil and Urban Engineering, New York Univ. Polytechnic School of Engineering, Six MetroTech Center, Brooklyn, NY 11201. 2 Researcher, Dept. of Civil and Urban Engineering, New York Univ. Polytechnic School of Engineering, Six MetroTech Center, Brooklyn, NY 11201. 3 Professor, Dept. of Civil and Urban Engineering, New York Univ. Polytechnic School of Engineering, Six MetroTech Center, Brooklyn, NY 11201. 4 Dept. of Civil and Urban Engineering, New York Univ. Polytechnic School of Engineering, Six MetroTech Center, Brooklyn, NY 11201. 5 Researcher, Fraunhofer Center for Sustainable Energy Systems, 5 Channel Center St., Boston, MA 02210. 6 Assistant Professor, Faculty of Engineering and Architectural Science, Ryerson Univ., 350 Victoria St., Toronto, ON, Canada M5B 2K3 (corresponding author). E-mail: uberardi@ryerson.ca 7 Chair, Dept. of Civil, Environmental, and Architectural Engineering, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609. 8 Associate Professor, Dept. of Civil, Environmental, and Architectural Engineering, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609. Note. This manuscript was submitted on November 19, 2014; approved on August 26, 2015; published online on December 14, 2015. Discussion period open until May 14, 2016; separate discussions must be submitted for individual papers. This paper is part of the Journal of Architectural Engineering, © ASCE, ISSN 1076-0431. © ASCE 05015001-1 J. Archit. Eng. J. Archit. Eng., 05015001 Downloaded from ascelibrary.org by Ryerson University on 12/28/15. Copyright ASCE. For personal use only; all rights reserved.