Masonry units made of clay or Autoclaved Aerated Concrete (AAC) are widely used in constructions from Romania and other countries. Masonry units with superior mechanical and thermal characteristics can improve the energy efficiency of buildings, especially when they are used as the main solutions for building envelope construction. Their production in recent years has increased vertiginously to meet the increased demand. Manufactured with diversified geometries, different mechanical and/or thermal characteristics have a high volume in the mass of the building and a major influence in their carbon footprint. Starting from the current context regarding the target imposed by the long-term strategy of built environment decarbonization, the aim of the paper is to analyze the potential of reusing mining waste in the production of masonry units. Mining waste represents the highest share of waste generated at national level and may represent a valuable resource for the construction industry, facilitating the creation of new jobs and support for economic development. This review presents the interest in integrating mining wastes in masonry unit production and the technical characteristics of the masonry units in which they have been used as raw materials in different percentages. Critical assessment framework using SWOT analysis highlights the key sustainability aspects (technical, environmental, social, economic) providing a comprehensive and systematic analysis of the advantages and disadvantages regarding the integration of mining waste as secondary raw materials into masonry units production.

Alternative energy resources have a significant function in the performance and decarbonization of power engendering schemes in the building application domain. Additionally, “green buildings” play a special role in reducing energy consumption and minimizing CO₂ emissions in the building sector. This research article analyzes the performance of alternative primary energy sources (sun and hydrogen) integrated into a hybrid photovoltaic panel/fuel cell system, and their optimal synergy to provide green energy for a green building. The study addresses the future hydrogen-based economy, which involves the supply of hydrogen as the fuel needed to provide fuel cell energy through a power distribution infrastructure. The objective of this research is to use fuel cells in this field and to investigate their use as a green building energy supply through a hybrid electricity generation system, which also uses photovoltaic panels to convert solar energy. The fuel cell hydrogen is supplied through a distribution network in which hydrogen production is outsourced and independent of the power generation system. The case study creates virtual operating conditions for this type of hybrid energy system and simulates its operation over a one-year period. The goal is to demonstrate the role and utility of fuel cells in virtual conditions by analyzing energy and economic performance indicators, as well as carbon dioxide emissions. The case study analyzes the optimal synergy between photovoltaic panels and fuel cells for the power supply of a green building. In the simulation, an optimally configured hybrid system supplies 100% of the energy to the green building while generating carbon dioxide emissions equal to 11.72% of the average value calculated for a conventional energy system providing similar energy to a standard residential building. Photovoltaic panels account for 32% of the required annual electricity production, and the fuel cells generate 68% of the total annual energy output of the system.

The present work examines an innovative manufacturing technique for fired clay bricks, using tuff as a secondary raw material. Samples were made of clay and tuff (0–30 wt.%) fired at 900 to 1100 °C. The chemical and mineralogical compositions and physical and thermal analyses of raw materials were investigated by using SEM-EDS, RX and DTA-TG curves. The samples were analysed from the mineralogical, technological and mechanical points of view. The result show that the tuff’s presence in the clay mixtures considerably reduced the shrinkage of the product during the firing process, and the manufactured samples were of excellent quality. The compressive strength of the bricks varied from 5–35.3MPa, being influenced by the tuff content, clay matrix properties and firing temperatures. Finally, the heat demand for increasing the temperature from room to the firing temperature of the sample with 10% tuff content was 22%.

The paper presents a simple and cost-effective way of enhancing the thermal conductivity of the paraffin/graphite phase change material (PCM) composite spheres manufactured by using a low-cost and eco-friendly method. The composite materials were made of an admixture of 5–20% vol. graphite powder. The manufacturing process of macro-encapsulated PCM consists of creating digital models, mold printing, and PCM injections. The experimental data shows that composite materials have an increased thermal conductivity, from 3 to 11 times compared to paraffin, and are effective in cooling application of electronic components where they lowered the maximum temperature up to 30 °C. For low-volume PCM sphere fabrication, it was proposed the injection molding in the 3D printed mold; the results show that fused deposition modeling (FDM) is efficient in saving energy up to 30% compared to machining. The carbon emissions generated during the fabrication technology were found to be strongly dependent on printing process parameters and the energy mix used to produce the electrical energy used.

Our aim was to investigate the feasibility of using limestone waste resulting from stone processing for the manufacturing of fired clay bricks. Waste materials were considered as a partial replacement for clays to reduce the exploitation of natural resources and as a response to the climate neutrality commitments. The samples were prepared to have a waste content of up to 15% and were fired at a temperature of 900 °C. The chemical and mineralogical composition and the physical analysis of raw materials were investigated by using SEM–EDS and XRD diffraction. The result showed an increase in CaO in the clay mixture due to the presence of limestone, which reduced the shrinkage of the products’ compressive strength, up to 55% for samples with a higher content of limestone (15 wt.%), and influenced the samples’ color by making them lighter than the reference sample.