• Energy Research

The design and study of low carbon buildings is a major concern in a modern economy due to high carbon emissions produced by buildings and its effects on climate change. Studies have investigated (CFP) Carbon Footprint of buildings, but there remains a need for a strong analysis that measure and quantify the overall degree of GHG emissions reductions and its relationship with the effect on climate change mitigation. This study evaluates the potential of reducing greenhouse gas (GHG) emissions from the building sector by evaluating the (CFP) of four hotpots approaches defined in line with commonly carbon reduction strategies, also known as mitigation strategies. CFP framework is applied to compare the (CC) climate change impact of mitigation strategies. A multi-story timber residential construction in Quebec City (Canada) was chosen as a baseline scenario. This building has been designed with the idea of being a reference of sustainable development application in the building sector. In this scenario, the production of materials and construction (assembly, waste management and transportation) were evaluated. A CFP that covers eight actions divided in four low carbon strategies, including: low carbon materials, material minimization, reuse and recycle materials and adoption of local sources and use of biofuels were evaluated. The results of this study shows that the used of prefabricated technique in buildings is an alternative to reduce the CFP of buildings in the context of Quebec. The CC decreases per m2 floor area in baseline scenario is up to 25% than current buildings. If the benefits of low carbon strategies are included, the timber structures can generate 38% lower CC than the original baseline scenario. The investigation recommends that CO2eq emissions reduction in the design and implementation of residential constructions as climate change mitigation is perfectly feasible by following different working strategies. It is concluded that if the four strategies were implemented in current buildings they would have environmental benefits by reducing its CFP. The reuse wood wastes into production of particleboard has the greatest environmental benefit due to temporary carbon storage.

Decorative wood panels containing pouches of bio-based phase changing materials (PCMs) were prepared. Three different PCM mixtures were used: a blend of capric and lauric acids as well as two commercial products, Puretemp®20 and Puretemp®23 (Puretemp). The panels consist of engraved Medium Density Fiberboard (MDF) filled with a plastic pouch filled with PCM. High density fiberboard (HDF) was used on top of the panels to enclose the PCM pouches. PCM mixtures were first tested by differential scanning calorimetry (DSC). Phase change temperature and total heat storage of the panels were measured for both fusion and solidification with a Dynamic Heat-Flow Meter Apparatus (DHFMA). DSC and DHFMA results were compared, allowing a better understanding of results gathered from these two techniques. DSC calibration has been revealed important when assessing PCMs. The panels present a phase change temperature and a latent heat storage suitable for buildings applications. The panel made with Puretemp®23 presented the highest energy, with 57.1 J g−1. Thermal cycling was conducted on the panels to investigate thermal reliability, which revealed small modifications of thermal properties for two products. For all cases, latent heat was found stable. Hygro-mechanical behavior of the panels was also evaluated as these where designed to be esthetic decorative panels. This study exposes the potential of a new type of wood-based panels loaded with PCM for thermal energy storage and brings overall knowledge about PCM products thermal characterization. Keywords: PCM, Wood, Biosourced, Fatty acids, DHFMA

Abstract Ecodesign is a concept that emerged few decades ago as a response to the larger concept of sustainable development. Multiple tools exist to address ecodesign. Life Cycle Assessment, a comprehensive, robust and recognized evaluation tool, enables to identify the product environmental profile. Based on previous LCA results on interior wood doors, this paper aims at proposing an ecodesign strategy based on the generation and evaluation of alternative scenarios. The three selected targets for environmental improvement are particleboard components, transportation and end-of-life. For the particleboard manufacturing, the use of adhesives based on bio-sourced resources was not very conclusive, except for the use of pine tannins in panel manufacture that showed promising results. Concerning transportation issues, switching from road to rail transportation, as well as having a local supplier, decreased the overall environmental impact of the door. The most notable alternative was the end-of-life recycling scenario. The reutilization of the door core in the door manufacturing process proved a great benefit due to the avoidance of new raw materials production. Developing services around door recovery and remanufacturing seems promising in reducing doors environmental impacts. This scenario would be readily viable and realistic.

Wood is increasingly perceived as a renewable, sustainable building material. The carbon it contains, biogenic carbon, comes from biological processes; it is characterized by a rapid turnover in the global carbon cycle. Increasing the use of harvested wood products (HWP) from sustainable forest management could provide highly needed mitigation efforts and carbon removals. However, the combined climate change benefits of sequestering biogenic carbon, storing it in harvested wood products and substituting more emission-intensive materials are hard to quantify. Although different methodological choices and assumptions can lead to opposite conclusions, there is no consensus on the assessment of biogenic carbon in life cycle assessment (LCA). Since LCA is increasingly relied upon for decision and policy making, incorrect biogenic carbon assessment could lead to inefficient or counterproductive strategies, as well as missed opportunities. This article presents a critical review of biogenic carbon impact assessment methods, it compares two main approaches to include time considerations in LCA, and suggests one that seems better suited to assess the impacts of biogenic carbon in buildings.

While externally insulated wall assemblies are widely recognized for their hygrothermal performance, few research projects have focused on the impact of shifting the entire wall insulation to the exterior side of a structural cavity in cold or subarctic climates or its effectiveness in terms of acoustic performance and airtightness. The objective of this study was to propose fully externally insulated assemblies that could be used in cold and subarctic climates by assessing the benefits of the hygrothermal performance of these assemblies and by achieving a comparable airtightness and sound transmission performance to the modern assemblies that are currently built in North America. The results suggested that the externally insulated assemblies limited the risk of condensation occurring inside structural cavities and allowed for faster drying than the modern assemblies when exposed to water infiltration or high water contents in all climates that were tested. The assemblies with external airtight insulation boards were more airtight than assemblies with air barrier membranes and, in addition, assemblies with external soundproof insulation were shown to be necessary to achieve a comparable sound transmission loss to that of a modern assembly.

Material selection in buildings profoundly affects project success, encompassing durability, maintenance, customer satisfaction, production systems, lifecycle, usage, environment, and costs. Yet, there is a need for further research on indicators for choosing materials in prefabricated buildings. Therefore, this study’s main objective was to identify the indicators (criteria and sub-criteria) for selecting materials for prefabricated wooden construction and, subsequently, categorize these criteria and sub-criteria based on the perspective of industry professionals. To achieve this goal, three phases were carried out. First, a literature review was conducted to identify potential criteria for choosing structural and envelope materials in wooden prefabricated buildings. Second, a pilot survey was conducted in Canada and the United States to classify the priority order of the criteria obtained from the literature based on professionals’ opinions. Finally, Monte Carlo simulations were conducted with different iterations (1000, 10,000, and 100,000) using the data obtained from the previous phase to improve decision-making and classification processes. For the indicators to select materials, the literature review identified seven main criteria: performance properties, green materials, energy efficiency, circular economy, site conditions and material logistics, standards, and social impact. These criteria contained a total of 25 sub-criteria. The pilot survey data analysis demonstrated that the performance properties, site conditions and material logistics, and social impact criteria were consistently prioritized. The critical sub-criteria identified were fire resistance, watertightness, local availability, occupant health, and safety and protection. For the Monte Calo simulations, the predictions aligned with the pilot study, enhancing the robustness of the results.

Abstract In the context of a low environmental impact energy mix, the embodied energy of building materials can account for up to 46% of a building's life cycle energy over a 50-year service life. Fifty percent of this energy corresponds to the combination of the structure and building envelope. While most studies have compared different residential building systems or wall assemblies, this study aims to quantify the contribution of initial embodied impacts to the environmental impacts of wall assemblies' life cycle for the exterior walls of an office building in Quebec City (Canada). Cradle-to-grave life cycle assessments were conducted on eight wall assemblies, three of which use light-frame construction, one lightweight steel framing, two cross-laminated timber and two glued-laminated timber in a post and beam approach. The life cycle impacts were evaluated using openLCA, the ecoinvent database and the TRACI method. Energy consumption during the use stage was simulated using EnergyPlus. The results indicate that initial embodied impacts can account for 40% to 66% of all environmental impacts throughout the wall assemblies' life cycle. These results suggest that, in this specific context, the initial embodied impacts can become the dominant source of environmental impacts in wall assemblies' life cycle. Many factors have been identified as affecting initial embodied impacts such as the choice, the quantity and the nature of materials. The results of this study will help decision makers to identify where efforts should be made to reduce a building's environmental impacts in similar context.

The popularity of prefabricated wooden buildings is increasing in North America, but choosing suitable materials for these structures can be complicated. This can lead to problems like financial losses, production delays, and lower quality. Therefore, the main goal of this study was to use the Analytical Hierarchy Process (AHP) decision-making tool to rank the criteria for material selection for prefabricated wood buildings in Canada and the United States. The methodology involved surveys experts in the prefabricated wood construction industry from Canada and the United States. The data obtained from the questionnaires utilized for the AHP analysis were modeled using R programming language. The results revealed that for structural materials, the top five subcriteria were safety and security of building occupants (0.234), location, shape, and height of the building (0.218), comfort, satisfaction, and well-being of the building (0.155), occupant health (0.121), and availability of materials (0.098). For selecting envelope materials, the top five subcriteria were comfort, satisfaction, and well-being of the building (0.252), safety and security of building occupants (0.206), location, shape, and height of the building (0.178), occupant health (0.132), and availability of materials (0.078).