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.

Inorganic alumino-silicates polymer or geopolymers are amorphous materials with a chemical composition similar to zeolites and an empirical overall chemical formula: M n[−(SiO2) z−AlO2] n · wH2O...

The scope of this work covers a proposal for the implementation of sustainable, low-cost, environmentally friendly, and affordable housing for low-income people. This paper aims to address the current housing issues, namely that many people lack decent housing and that the built houses are usually of a poorly sustainable nature. The work consists of three main parts: an evaluation of housing sustainability, measurement of parameters related to their internal comfort and a simulation of thermal enclosure with the COMSOL Multiphysics^® software. An important objective is to propose a sustainability assessment format, which, besides being explained in detail, is presented in a percentage scale for ease of understanding. This work seeks a methodology for evaluating the level or degree of sustainability for the construction and inhabitation stages of housing. Using a prototype constructed with polyethylene terephthalate (PET) bottles, temperature and humidity were measured. There was a contrasting behavior of these two parameters, which tended towards an inverse behavior, except on cloudy or rainy days. The roof of the prototype contained some waste materials that provided thermal insulation: galvanized steel, polyethylene bags for upcycling as waterproofing, PET bottles, soil and endemic plants (green roof). The results obtained in the simulation are in accordance with the real internal behavior of the prototype.

Geopolymers have been mainly utilized as structural materials; their chemical structure and morphologies have been explored for their potential as a high-performance material in emerging applications. Geopolymer composites reinforced with materials based on agro-waste are attracting interest in engineering applications due to their easy processing, low cost, low density, and high strength-to-weight ratio. This investigation pursues an experimental methodology that consists of a scheme to make composites with a geopolymer matrix and agro-waste (rice husk, barley, and coffee) as aggregate material, that can be applied in various fields of construction. The study was intended to determine the influence of adding various agro-wastes on the mechanical properties of the geopolymer. According to the respective ASTM standards, the materials obtained were prepared and analyzed to determine their compressive strength, flexural strength, hardness and scanning electron microscopy (SEM)-determined characteristics. The results revealed that, for the compression tests, the composites formed by a sol-gel matrix and barley husk showed a better yield, obtaining the highest value of 3.5 N/mm². Concerning hardness testing, the composites with a geopolymer matrix and coffee husks obtained higher values compared to the other composites. For the flexural tests, the compounds with the sol-gel/fly ash matrix obtained the highest yield stress value, which was 5.25 MPa with an elastic modulus of 7.59 GPa. The results of the microstructural analysis showed good husk-matrix interaction, together with failure mechanisms. The conformation of such waste-based compounds may enable them to replace natural wood in some applications, such as in the finishing of interiors of homes, during the final stages in the construction of buildings, or in the decoration of inhabited houses, as well as in finishing in the manufacture of furniture.