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Urban building energy models (UBEMs), developed to understand the energy performance of building stocks of a region, can aid in key decisions related to energy policy and climate change solutions. However, creating a city-scale UBEM is challenging due to the requirements of diverse geometric and non-geometric datasets. Thus, we aimed to further elucidate the process of creating a UBEM with disparate and scarce data based on a bottom-up, physics-based approach. We focused on three typically overlooked but functionally important commercial building stocks, which are sales and shopping, healthcare facilities, and food sales and services, in the region of Pittsburgh, Pennsylvania. We harvested relevant local building information and employed photogrammetry and image processing. We created archetypes for key building types, designed 3D buildings with SketchUp, and performed an energy analysis using EnergyPlus. The average annual simulated energy use intensities (EUIs) were 528 kWh/m2, 822 kWh/m2, and 2894 kWh/m2 for sales and shopping, healthcare facilities, and food sales and services, respectively. In addition to variations found in the simulated energy use pattern among the stocks, considerable variations were observed within buildings of the same stock. About 9% and 11% errors were observed for sales and shopping and healthcare facilities when validating the simulated results with the actual data. The suggested energy conservation measures could reduce the annual EUI by 10–26% depending on the building use type. The UBEM results can assist in finding energy-efficient retrofit solutions with respect to the energy and carbon reduction goal for commercial building stocks at the city scale. The limitations highlighted may be considered for higher accuracy, and the UBEM has a high potential to integrate with urban climate and energy models, circular economy, and life cycle assessment for sustainable urban planning. [ABSTRACT FROM AUTHOR]

Abstract A rapid development of building environmental research from the globe is witnessed in recent years to deal with the environmental issues, especially in terms of energy consumption and carbon emissions, due to the substantial environmental burdens associated with the building industry. Thus, numerous scientific efforts have been devoted to buildings through environmental assessment like a life cycle assessment (LCA) and a methodological framework development. Concerning the rapid growth of buildings, LCA is increasingly used for assessing and mitigating the associated environmental impacts from material selection to the whole building systems. This study aims to comprehensively review the LCA implication on buildings by discussing the contemporary issues related to the development of this research field. The study considers a wide range of literature including case studies, reviews and surveys, and these articles are critically examined according to the predefined criteria developed. An in-depth analysis is also conducted on selected studies to unveil the criticality of the assessments and results under different considerations. In addition to demonstrating the research gaps for comprehensive assessment of buildings, the adoption of a circular economy (CE) concept is highlighted by providing a comprehensive framework. The findings show that resource recovery and resource-efficient building construction are seldom considered in prevailing studies. As a result, the framework proposed in this paper should help support a paradigm shift towards a comprehensive research for increasing the accuracy and practicability by introducing the CE principle to the building industry for enhancing its sustainability performance. Highlights • Literature related to building-environmental research was critically analyzed. • LCA implication on buildings was comprehensively reviewed by discussing the contemporary issues. • Selected papers were critically analyzed to unveil the research trends and practices. • Knowledge gaps for comprehensive assessment of buildings under the CE principle are identified. • Comprehensive framework based on the CE principle was proposed for comprehensiveness building LCA. [ABSTRACT FROM AUTHOR]

The management of a large amount of wood waste generated from construction activities is a challenging issue. However, wood waste is an inherently renewable resource that can be recycled and utilized for the production of green products and renewable energy. In order to minimize the environmental impacts and to provide a scientific basis for the decision-making process on the wood waste management systems, a life cycle assessment (LCA) approach was employed in this study to evaluate the potential management systems from an environmental point of view. Three alternative scenarios, including the recycling and reusing of wood waste to produce organic polymer based particleboard, cement-bonded particleboard and energy were compared with the current disposal strategy (landfill disposal), with the functional unit of 1 tonne of wood waste within a cradle-to-grave system boundary. The LCA results showed that significant reductions of environmental impacts were observed for the production of particleboard (scenario 1) and wood-cement composite (scenario 2) from wood waste compared to that of using virgin wood. However, the results also showed that scenario 3 (energy generation from bio-fuel derived from wood waste) was the best strategy, as this technology reduces more than 1 tonne of CO 2 eq greenhouse gases compared to the energy generation from coal. The analysis conducted in this study can serve as guidelines to design a sustainable and resource-efficient wood waste management system. [ABSTRACT FROM AUTHOR]

Cement is traditionally regarded as an energy and emission intensive construction material. The reduction of environmental impacts in the cement industry has gained increasing concern worldwide for environmental sustainability. As a resource-scarce city, cement production in Hong Kong is associated with high CO 2 emissions, thus contributing significantly to the high environmental impacts in the construction industry. This study herein has been conducted to comprehensively assess the energy consumption and global warming potential impacts of different types of cement manufactured in Hong Kong using life cycle assessment (LCA) techniques. Two sustainable strategies for the reduction of energy consumption and greenhouse gases emission in the cement industry were then proposed. The LCA results showed that ordinary Portland cement production has high environmental impacts mainly due to the import of associated raw materials and burning of fossil fuel. The use of alternative material, such as fly ash would help to reduce the environmental impacts. Significant impacts reductions associated with cement production can be further achieved by strategies such as the use of glass powder from locally generated waste glass bottles as part of the raw materials, and the use of a bio-fuel produced from locally generated wood wastes as a co-fuel with coal. The assessment results indicated that about 12% of the total greenhouse gases emission and 15% of energy consumption can be reduced from the cement industry in Hong Kong by using waste materials to replace virgin materials (clinker/coal). [ABSTRACT FROM AUTHOR]

• A food-energy-water-waste nexus analysis can aid in low carbon city design. • System dynamic modeling analysis synthesizes low carbon city initiative. • Scenario planning helps identify decarbonization pathways for prioritization. The retrofit of existing buildings at a community scale can provide a huge opportunity to reduce the community's energy consumption and subsequent greenhouse gas (GHG) emissions in support of the United Nations agenda for net-zero emissions and decarbonization. This study demonstrates a community-scale food-energy-water-waste nexus through 6 alternatives (A1–A6) by highlighting decarbonization pathways with system dynamics modeling. Several potential retrofit alternatives are proposed for analyzing building energy consumption, energy requirements for rooftop or greenhouse crop production, and potential energy and water savings from renewable energy harvesting. Such a nexus analysis is designed to integrate (1) building energy consumption, (2) waste management and water consumption, and (3) GHG emissions based on life-cycle assessment to prioritize alternatives. The incorporation of solar photovoltaic (PV) systems (i.e., rooftop, parking lot, parking garage, and floating solar PV) sustains approximately 72% of net energy demand (alternative A3), while the integration of all solar, wind, and anaerobic digestion alternatives provides around 41% of net energy demand (alternative A6). It is vital to emphasize decarbonization pathways through the use of renewable energy by 2030 in alternative A5 (i.e., solar and wind energy) and A6, both of which avoid energy consumption from the utility grid and result in 250% total carbon emissions offset. [ABSTRACT FROM AUTHOR]