Cost-effective and environmentally responsible ways of carbon fiber-reinforced composite (CFRP) recycling are increasingly important, owing to the rapidly increasing use of these materials in many industries such as the aerospace, automotive and energy sectors. Product designers need to consider the costs associated with manufacturing and the end-of-life stage of such materials to make informed decisions. They also need to understand the current methods of composite recycling and disposal and their impact on the end-of-life costs. A comprehensive literature review indicated that there is no such tool to estimate CFRP recycling costs without any prior knowledge and expertise. Therefore, this research paper proposed a novel knowledge-based system for the cost modelling of recycling CFRP that does not require in-depth knowledge from a user. A prototype of a cost estimation system has been developed based on existing CFRP recycling techniques such as mechanical recycling, pyrolysis, fluidized bed, and supercritical water. The proposed system has the ability to select the appropriate recycling techniques based on a user’s needs with the help of an optimization module based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Estimating recycling costs has taken into consideration various factors such as different material types in different industries, transportation, and dismantling costs. The developed system can be employed to support early-stage designers and decision-making stakeholders in terms of understanding and predicting recycling costs easily and quickly.

Fiber-reinforced composites, such as carbon and glass fibers, are widely used across various industries. This is mainly a result of their outperforming properties in contrast with traditional materials. As a response to the environmental legal enforcement of the recycling of composite materials, several recycling methods such as mechanical, thermal, and chemical recycling, have been developed. Despite various merits, these recycling methods still face challenges, such as the heterogeneity of material, the quality of the recycled product, the high cost of recycling, and a lack of an established market. Since, in many cases, the financial aspect tends to be the major barrier to recycling composites, the appropriate cost modelling of the recycling process requires urgent consideration. To the knowledge of the authors, there is no prior research efforts on the reviewing of cost modelling techniques on composites recycling. Cost modelling research projects for different recycling technologies, with their findings and limitations, are sought from the literature and reported in this paper. It is found that recycling techniques still cannot compete with traditional landfilling in terms of cost, and are dependent on fiber recovery rates and plant capacities. Following a comprehensive literature review, research gaps are identified to formulate the research directions in this field.

The role of buildings in the context of addressing the consequences of climate change and the energy deficit is becoming increasingly important due to their share in the overall amount of green house gas (GHG) emissions and rapidly growing domestic energy consumption worldwide. Adherence to a sustainability agenda requires ever-increasing attention to all stages of a building′s life, as such approach allows for the consideration of environmental impacts of a building, from design, through construction stages, until the final phase of a building′s life—demolition. A life cycle assessment (LCA) is one of the most recognized and adopted models for the evaluation of the environmental performance of materials and processes. This paper aims to perform an LCA of four different types of residential buildings in Nur-Sultan, Kazakhstan. The assessment primarily considered embodied energy and GHG emissions as key assessment indicators. Findings suggest that the operational stage contributed to more than half of the GHG emissions in all the cases. The results of the study indicate that there is a dependence between the comfort levels and the impact of the buildings on the environment. The higher the comfort levels, the higher the impacts in terms of the CO₂ equivalent. This conclusion is most likely to be related to the fact that the higher the comfort level, the higher the environmental cost of the materials. A similar correlation can be observed in the case of comparing building comfort levels and life-cycle impacts per user. There are fewer occupants per square meter as the comfort level increases. Furthermore, the obtained results suggest potential ways of reducing the overall environmental impact of the building envelope components.