Structural aspects of building conversions in industrial areas

Abstract

The conversion of buildings in industrial locations, known as brownfields, is of interest to cities and municipalities practically all over the world. The conversion of buildings in industrial locations always includes a number of assessment aspects that need to be addressed, including the thermal and energy properties of the buildings. The research in this work focuses on the outer shell of a selected skeletal building and the analysis of critical details. It includes monitoring selected material characteristics of the new design of the outer shell, so that the appropriate design takes into account not only thermal parameters, but also climate neutrality, in accordance with the strategy of EU legislative documents. This work emphasizes conversions for residential purposes, such as apartment buildings, housing for the elderly, loft housing, etc., because the demand for affordable and sustainable housing in urban areas is growing rapidly. Reusing existing abandoned industrial buildings for residential purposes can simultaneously address environmental and social challenges by preserving the urban footprint, minimizing construction waste, and setting the rules for a circular economy. All of this is in line with sustainable development. In many post-industrial areas of Europe, existing industrial buildings are characterized by uninsulated brick walls with poor thermal properties, although their steel or concrete frame structures usually remain structurally functional. These properties make these structures strong candidates for conversion. The work presents a thermal performance assessment, structural evaluation, and compliance with current energy regulations. Building envelope models are created to investigate heat transfer through multi-layer wall systems, taking into account thermal bridges, material properties, and insulation quality. Numerical simulations are used to evaluate heat losses in different conversion scenarios. The simple additive weighting (SAW) method was used to evaluate wall systems using different performance criteria. Furthermore, a life cycle assessment (LCA), A1-A3, was assessed to quantify the carbon content of different wall configurations. The results present practical and sustainable strategies for converting and reusing abandoned industrial buildings. A comparative analysis of the U-values for the different wall systems compared to national building codes shows a significant improvement in thermal performance of the proposed retrofitted walls. The reference wall, which represents an existing post-industrial frame building, has a high U-value of 1.41 [W/(m².K)], indicating significant heat losses. In contrast, all proposed wall systems achieve much lower U-values, ranging from 0.351 to 0.17 [W/(m².K)], which meet or exceed current regulatory requirements in several European countries. It is evident that the BP-EPS wall has the lowest U-value of 0.172 [W/(m².K)], thus surpassing even the most stringent standards. The material arrangement of FC-EPSR reduces thermal bridges due to a more symmetrical and concentrated isothermal pattern. In addition, there are shorter cold zones and less deformation near the corner compared to the BP-EPS wall. In addition, the FC-EPSR wall has a better 2D heat flow distribution due to smoother thermal transitions between layers and better thermal contact between layers. All these factors ultimately lead to a smaller temperature depression at the inner corner (higher Tsi), even with a slightly higher U-value. Overall, the findings underline the importance of advanced materials to achieve efficient thermal performance while balancing architectural and structural requirements. The results of experimental modelling show that industrial buildings can be effectively thermally renovated in a manner that is in line with legislative documents and successfully extend the physical lifetime of the frame structures and create potential for carbon neutrality.