Use of microencapsulated PCM in buildings and the effect of adding awnings

In 2004 the University of Lleida began working on the inclusion and effects of PCM into concrete and performed experiments employing microencapsulated PCM integrated into concrete walls under different configurations (free-cooling, open windows, etc.). One of the main drawbacks found was the severe influence of high outdoor temperature peaks and solar radiation over the PCM during the summer, which prevented its solidification during night and thus diminished its achievable potential benefits. The main objective of this work is to overcome such a problem and increase the operation time of the PCM and the thermal comfort achieved. For such a purpose, in 2008-2009 similar experiments have been performed with awnings added to the set-up, providing them with solar protection. This paper discusses the observed effects over the PCM activation, comfort conditions inside the building, and compares them to those obtained without employing awnings. Results showed that peak temperatures were reduced about 6%. Moreover, PCM remained active for at least 4% more hours, and the comfort time was increased at least 10% in cubicles with awnings. However, the effect of high outdoor temperatures and solar radiation was not overcome completely as PCM did not complete full phase change cycles everyday as desired. (C) 2011 Elsevier B.V. All rights reserved.