Performance of passive application of PCM in Spain

Abstract

Contemporary construction systems tend to be thinner, lighter and better insulated than ever, but usually lack thermal mass. In order to improve the indoor temperature and reduce the energy consumption in the lightweight building it is necessary to add thermal energy storage capacity to the construction elements. Phase change materials (PCM) have high a heat of fusion so they can absorb a lot of thermal energy before melting or solidifying without adding physical mass. The stored energy can be released later when it is necessary. The main purpose of this study is to quantify the effectiveness of PCMs as interior temperature stabilizers in the Spanish construction. Another goal was to identify the influence of the windows sizes and their shading factor in a PCM´s passive application, and find out the most convenient combinations. A comparative study has been made, simulating a Test Room, with and without PCM, to predict the annual interior temperature behavior in each case. The thermal performance of the test rooms was evaluated on an hour to hour basis, in several Spanish climate zones with diverse combinations of facade glazing ratio and window shadow factors (Fs). The results indicate that the addition of PCM to building partitions help to maintain the interior thermal comfort, reducing the high and low temperature peaks in all Spanish climates studied. The PCM thermal stabilizing capacity is more noticeable in summer. However, the Test Room in the warmer climate falls behind in the overall results. The PCM passive application has demonstrated to help to maintain a uniform interior temperature and to save energy, but its use is not a cost effective solution for all the cases in the study. This study helps to identify when, and where, the use of this PCM application should be more appropriate.