Energy and Buildings 86 (2015) 86–92 Contents lists available at ScienceDirect Energy and Buildings j ourna l ho me pa g e: www.elsevier.com/locate/enbuild On the use of plug-and-play walls (PPW) for evaluating thermal enhancement technologies for building enclosures: Evaluation of a thin phase change material (PCM) layer Kyoung Ok Lee a , Mario A. Medina a,∗ , Xiaoqin Sun b a Civil, Environmental & Architectural Engineering Department, The University of Kansas, Lawrence, KS 66045, USA b School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha, Hunan 410004, PR China a r t i c l e i n f o Article history: Received 17 June 2014 Received in revised form 3 September 2014 Accepted 9 October 2014 Available online 22 October 2014 Keywords: Plug-and-play walls (PPW) Building enclosure Phase change materials (PCM) Thermal energy storage Wall heat transfer Construction materials a b s t r a c t Experimental research is critical for the testing and development of new products as well as for the validation and verification of simulation models. In this paper, a novel way for testing various kinds of wall constructions, known as plug-and-play walls (PPW), is introduced. The PPW concept provides the flexibility to test most kinds of wall constructions in real time. It allows for the faster installation and dismantling of the test walls. The use of the PPW concept was demonstrated by evaluating the thermal performance of a thin phase change material (PCM) layer, herein referred to as “PCM thermal board (PCMTB).” The results showed that the average daily heat transfer reductions were 27.4% and 10.5% for south and west facing walls, respectively, and the average heat flux reductions when the heat fluxes of the control walls were at their peaks were 67.0% and 80.2% for the same orientations, respectively. It was demonstrated that the integration of a thin PCM layer also delayed the peak heat transfer rate per unit of wall area on an average of two to three hours. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Experimental research is fundamental for discovery and advancement of science. Similarly, it is crucial for the development of new products. In fact, simulation models are often validated and verified against experimental data. However, compared to com- puter simulations, experiments are often more expensive. In the field of building energy research, including heat and mass transfer studies in walls, ceilings, roofs, foundations, and windows, hav- ing the appropriate test buildings is very important and necessary. However, finding appropriate test buildings represents a prob- lem, typically because dedicated unoccupied buildings are often scarce to non-existent because of their cost, space requirements, and maintenance. In addition, if appropriate test buildings exist, at least two are often required, one to be used as a control building and the other for use as a retrofit building. In such a case, the calibra- tion of both buildings (i.e., establishing their similarity in thermal performance prior to any retrofit) is difficult to accomplish and the level of difficulty increases with building size. This is the reason why researchers often use smaller replicas of typical buildings. ∗ Corresponding author. Tel.: +1 785 864 3604; fax: +1 785 864 5631. E-mail addresses: mmedina@ku.edu, mmedinaks@gmail.com (M.A. Medina). The aim of this paper is two-fold: (1) to present a novel method for testing walls (i.e., the plug-and-play wall (PPW) system, and (2) to present one example of how the PPW concept can be used. The example was the evaluation of the performance of a thin phase change material (PCM) layer, herein referred to as “PCM thermal board (PCMTB),” which was commercially-available [1]. One way to create a convenient way for testing various kinds of wall constructions with relative ease is the concept of plug-and- play walls (PPW). The advantages of the PPW system include: (a) the easiness by which new or different types of walls (e.g., brick walls, concrete walls, several types of residential walls, several types of commercial walls, traditional walls from other parts of the world, etc.) can be assembled and mounted for testing, and (b) the testing of a significant number of different wall types at the same time under real conditions where all the walls are exposed to the same identical outdoor as well as indoor conditions. In the long run this concept results in a more convenient and less expensive way of testing walls than having to construct several small test chambers. Some of the many reasons for this include material quantity, labor cost, space, indoor conditions control, and instrumentation. Recently, most PCM researchers have advocated the integration of PCMs into walls via micro-encapsulation [2–5]. This method of PCM integration may lead to incomplete melting and solidification of the PCM, mainly because of the location of the micro-capsules. In http://dx.doi.org/10.1016/j.enbuild.2014.10.020 0378-7788/© 2014 Elsevier B.V. All rights reserved.