A review of micro level indicators for a circular economy – moving away from the three dimensions of sustainability?

Traditional, state-of-the-art and renewable thermal building insulation materials: An overview

Reconfigurable manufacturing systems: Literature review and research trend

Circular economy business models and operations management

Building envelope insulation is crucial for an energy-efficient and comfortable indoor environment because the envelope accounts for 50–60% of total heat gain/loss in a building. Previous studies mostly used lifecycle cost as the criteria to select the optimum insulation materials with little or no consideration of embodied energy, emission, and summer overheating potential. This study presents a comparative analysis of building insulation materials properties (thermal, hygroscopic, acoustic, reaction to fire, environmental, and cost) and their performance in different climate zones and proposed an optimization framework. Insulation materials can be primarily categorized as conventional, state-of-the-art and sustainable. State-of-the-art insulation materials have the lowest thermal conductivity value amongst the three insulation types. However, their life cycle cost is higher compared to the other types. Sustainable insulation materials could be useful to delay and minimize indoor peak temperature and reduce overheating risk during the hot summer period. The analysis also showed that building walls with comparatively lower thermal resistance are more cost-effective for the cooling dominated region, but walls with higher thermal resistance are more cost-effective in heating-dominated regions. However, highly insulated and airtight houses may also lead to increased overheating risk and peak cooling demand during a hot summer period. In addition, hygroscopic, acoustic, and fire retardancy properties of insulation materials are critical to control indoor relative humidity in a humid region, to maintain a minimum noise level in a zone, and to reduce fire destruction. Hence, the optimization should include four criteria 1) Energy, 2) Environment, 3) Economic, and 4) Comfort.

Comparative analysis of building insulation material properties and performance

Developing a set of sustainability indicators for product families based on the circular economy model

Cellulose-based aerogels hold the potential to become a cost-effective bio-based solution for thermal insulation in buildings. Low thermal conductivities (<0.025 W·m−1·K−1) are achieved through a decrease in gaseous phase contribution, exploiting the Knudsen effect. However, several challenges need to be overcome: production energy demand and cost, moisture sensitivity, flammability, and thermal stability. Herein, a description and discussion of current trends and challenges in cellulose aerogel research for thermal insulation are presented, gathered from studies reported within the last five years. The text is divided into three main sections: (i) an overview of thermal performance of cellulose aerogels, (ii) an identification of challenges and possible solutions for cellulose aerogel thermal insulation, and (iii) a brief description of cellulose/silica aerogels.

Cellulose Aerogels for Thermal Insulation in Buildings: Trends and Challenges

The Circular Economy comprises several strategies to enhance the sustainability of products. However, most of the research in this area has focused on Recycling, Recovering and final disposal. Strategies for lifespan extension such as Reuse, Repair, Refurbish, Remanufacture and Repurpose lead to higher circularity and value throughout the lifecycle but are less studied. Here we propose a single generic indicator based on durability and environmental footprint for material selection as an early step in the design process towards extending product lifespan. The material durability indicator or MDI integrates into a single calculation chemical and mechanical durability, together with environmental impacts associated with the material. The proposed indicator incorporates parameters such as flammability resistance, resistance to ultraviolet radiation, resistance to water, resistance to organic solvents, mechanical strength, energy consumption, and carbon footprint, among others. A case study based on polymer materials selection demonstrates the usefulness of the MDI indicator, providing a holistic calculation and comparison of selection alternatives, including conventional and multicriteria approaches. The proposed indicator offers a balanced and technical measurement of durability and environmental burdens in the material selection process and can potentially be applied to any engineering material.

Developing an indicator for material selection based on durability and environmental footprint: A Circular Economy perspective

Life Cycle Assessment (LCA) is considered an innovative tool to analyze environmental impacts to make decisions aimed at improving the environmental performance of building materials and construction processes throughout different life cycle stages, including design, construction, use, operation, and end-of-life (EOL). Therefore, during the last two decades, interest in applying this tool in the construction field has increased, and the number of articles and studies has risen exponentially. However, there is a lack of consolidated studies that provide insights into the implementation of LCA on construction and demolition waste (C&DW). To fill this research gap, this study presents a literature review analysis to consolidate the most relevant topics and issues in the research field of C&DW materials and how LCA has been implemented during the last two decades. A systematic literature search was performed following the PRISMA method: analysis of selected works is based on bibliometric and content-based approaches. As a result, the study characterized 150 selected works in terms of the evolution of articles per year, geographical distribution, most relevant research centers, and featured sources. In addition, this study highlights research gaps in terms of methodological and design tools to improve LCA analysis, indicators, and connection to new trending concepts, such as circular economy and industry 4.0.

Life Cycle Assessment on Construction and Demolition Waste: A Systematic Literature Review

Nowadays sustainable design is a mandatory requirement in the product development process. For this reason, design methodologies are addressed to establish a close relationship between environmental, social and economic impact indicators and product features from early design stages, especially in those features related to its manufacturing. In this paper, the design for manufacturing and assembly—DFMA methodology is adapted to sheet metal enclosure devices, integrating functional and component relationships to minimize particular sustainability indicators such as energy consumption, carbon footprint, number of parts, required amount of material, assembly time and manufacturing costs. Savings with the proposed method are achieved following specific sub-tasks oriented to define new simplified product components, considering changes in manufacturing processes and re-defining mechanical connections between parts. Traditional DFMA approaches consider manufacturing and assembly issues related to a reduction of product complexity and economic savings. The proposed method aims to examine the benefits in life cycle stages such as raw material consumption, service, maintenance, upgrading and end of life—EOL. The methodology is validated through a redesign of a sheet metal industrial clock, in which the sustainability impacts are calculated from a comparison of an existent product vs. a new product development. The implementation of the method in the case study demonstrate reductions of more than 25% in product mass, consumed energy and CO2 footprint, and more than 50% in theoretical assembly time and product complexity. Sustainability indicators of the proposed method are selected from literature analysis and taking into account attributes of sheet metal enclosure devices.

Jaime Mesa

Papers

Developing a set of sustainability indicators for product families based on the circular economy model

Cellulose Aerogels for Thermal Insulation in Buildings: Trends and Challenges

Developing an indicator for material selection based on durability and environmental footprint: A Circular Economy perspective

Life Cycle Assessment on Construction and Demolition Waste: A Systematic Literature Review

A novel approach to include sustainability concepts in classical DFMA methodology for sheet metal enclosure devices