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The energy sector is one of the fields of interest for different nations around the world. Due to the current fossil fuel crisis, the scientific community develops new energy-saving experiences to address this concern. Buildings are one of the elements of higher energy consumption, so the generation of knowledge and technological development may offer solutions to this energy demand, which are more than welcome. Phase change materials (PCMs) included in building elements such as wall panels, blocks, panels or coatings, for heating and cooling applications have been shown, when heating, to increase the heat storage capacity by absorbing heat as latent heat. Therefore, the use of latent heat storage systems using phase change materials (PCMs) has been investigated within the last two decades. In the present review, the macro and micro encapsulation methods for construction materials are reviewed, the former being the most viable method of inclusion of PCMs in construction elements. In addition, based on the analysis of the existing papers on the encapsulation process of PCMs, the importance to pay more attention to the bio-based PCMs is shown, since more research is needed to process such PCMs. To determine its thermophysical and mechanical behavior at the micro and macro levels, in order to see the feasibility of substituting petroleum-based PCMs with a more environmentally friendly bio-based one, a section devoted to the excellent PCM with lightweight aggregate (PCM-LWA concrete) is presented due to the lack of description given in other reviews.

A novel differential photoacoustic cell (DPC) for the study of dynamical processes has been developed. The DPC has the capability to measure in real time the amplitude and phase signals for the reference and the sample under study. The simultaneous measurement of both signals eliminates the instrumental function, and the presence of noise, due to any deviation originated by electrical, optical, and environmental factors. The DPC can be used at different temperature profiles in order to obtain the instrumental function IF(t,T). The DPC also has all the elements of an electrochemical cell capable of following the electrochemical processes. As a result of this new instrumentation it is possible to obtain in real time the amplitude and phase signals coming from the sample without any interference from the system and the viability to monitor in situ electrochemical and thermal processes. Two cases are presented as an illustrative demonstration of work fields: the electrodeposition of zinc on a steel substrate as well as the study of water and calcium ion diffusion into organic layers.

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