One of the solutions for overheating the interior in the summer without increasing energy consumption is the integration of phase change material (PCM) into interior plasters. However, adding PCM to plasters deteriorates their properties and thus their usability. The aim of this paper is to determine how the microencapsulated PCM affects the mechanical, thermal, and fire properties of plasters and how much PCM can be added to the plaster. Two sets of samples were prepared: in set S, part of the aggregate was replaced by PCM; and in set R, only PCM was added. The bulk density, flexural strength, compressive strength, tensile strength perpendicular to the surface, thermal conductivity coefficient, specific heat capacity, melting, and solidification temperatures and enthalpy were measured. A single-flame source fire test and a gross heat of combustion fire test were performed to determine the reaction to the fire class. The results show that with an increasing proportion of PCM, the strength of the samples of set R decreased more significantly than it did with the samples of set S. It was found that only up to about 10% PCM could be added to set R, while up to 30% PCM could be added to set S.

The external walls of buildings account for a substantial part of the financial costs of the entire construction, and there can be a loss of up to 35% of thermal energy through them. By properly optimizing the price for the construction of m² of the external wall structure and its thermal technical parameters, interesting savings can be achieved. At present, there is no multi-criteria analysis for designing external wall structure compositions involving broader input options according to the user’s technical parameters and priorities. There is a large selection of special software in the Czech and European markets, but the software is focused only on the narrower area of design and ignores the issue of building material prices. The aim of this work is to create an algorithm that reliably finds the composition that best meets the user’s requirements using a wide database of materials and selected mathematical methods. This article presents an algorithm that would design the ideal composition of an external wall. This algorithm has two options for searching. The first is based on eight technical criteria and the prices of materials used in combination with user priorities. The second option is to find the best composition based only on the specified interval of the selected technical parameters. Materials databases and the use of existing computational methods, such as the Saaty method and the WSM—weighted sum method, applied to the algorithm are essential to find the composition. According to the assignment, the structures will be clearly quantified in values from 1 (best) to 0 (worst). The algorithm, which is based on the analysis of data, sources, and theories of multi-criteria decision-making, should, therefore, facilitate the design of the external wall. At the end of this article, there is a verification of the functionality of the algorithm on a case study. We believe that software that uses the proposed algorithm could be very useful for practice.

Geochemical modeling in TOUGHREACT code was used to simulate chemical processes in CO₂–rock–brackish water systems in a pilot research environment of CO₂ storage in the Brodske area (Czech Republic). Models studied mineralogical changes in rock samples resulting from acidification of the aqueous phase caused by the dissolution of pressurized supercritical CO₂. Rock samples of the reservoir horizon and cement from the grouting of an injection borehole were considered, and the water phase represented the mineralized groundwater. The aim of the study was to characterize the influence of CO₂ in the geological structure on mineralogical rock changes and to predict gas distribution through the rocks bearing brackish water. The most important chemical processes are dissolution of carbonates and clay minerals during the injection of CO₂ into the structure, as the increase in porosity in the structure affects the sequestration capacity of the reservoir rock. In the CO₂–cement–brackish water system, the models confirm the rapid dissolution of portlandite and its replacement with calcite. The CSH gel is also dissolved, and silica gel appears. The porosity of the cement decreases. Further studies on such a cement slurry are needed to prevent the possibility of mechanical damage to the integrity of the borehole.