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1. Construction Cost Decomposition of Residential Building Energy Retrofit

   https://doi.org/10.3390/buildings13061363  

   Zhao, Dong; Mo, Yunjeong (June 2023, Buildings)

   Buildings are responsible for significant energy consumption and carbon emissions. Green buildings, which incorporate advanced building technologies, offer a solution to reducing energy use. However, high costs associated with green building development present a barrier to widespread adoption. Retrofit projects, involving remodeling, renovation, and redevelopment of existing buildings, offer a viable solution. While prior studies have examined the cost analysis of green and non-green buildings, there is a lack of evidence comparing new and retrofit projects. This study aims to address this gap by providing empirical evidence for the cost decomposition and benefits of new and retrofit projects. Data on energy use, building technology, and costs from 235 certified green homes in the United States were collected, and cost benefits were evaluated. Results show that retrofit projects cost, on average, $1270.5/m2 ($118.0/ft2), which is 30% less than new projects. Land acquisition and development account for 35% of retrofit costs, six times greater than new projects. Excluding land costs, retrofit projects cost, on average, $733.88/m2 ($68.2/ft2), 49% less than new projects. Retrofit projects use similar building technologies as new projects and produce larger energy savings. The cost-benefit values generated by retrofit projects are 86% greater than new projects when considering land costs and 142% greater without considering land costs. These findings contribute to cost management for complex building projects and energy policy for sustainable development. Retrofitting offers great potential to promote the green building movement and suggests effective subsidy programs as a public policy implication. 

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2. (2023, June). Moralizing Design Differences in the North: An Ethnographic Analysis. In 2023 ASEE Annual Conference & Exposition.

   Nicewonger, T. E.; Fritz, S. A.; McNair, L. D. (June 2023, 2023 ASEE Annual Conference & Exposition.)

   Addressing the 2023 theme of Global Responsibilities of Engineers, in particular the disproportionate impacts of climate change on communities in remote regions of Alaska, this paper tracks the “social life” of a prefabricated frame assembly system designed for constructing homes in emergency contexts in northern Alaska (Appadurai 1986). An Alaskan housing research center began using this prefabricated system over a decade ago, in a time of crisis caused by major spring flooding in an Alaskan riverine community that has long grappled with housing shortages. The destruction of these homes, along with the possessions of the people living in them, was a tremendous loss to this community. The region’s short building season and dependency on barge and aerial transportation services for shipping in building supplies further compounded these challenges. In response, local and federal agencies came together and decided on a housing design that uses an integrated wall and truss system that could be prefabricated off-site, shipped out, rapidly assembled by volunteer building crews in the affected site, and that facilitated a highly insulated energy efficient home. As a result, this design played a critical role in mediating further disaster. Fast-forward to the present, the housing research center continues to opt for this system for most remote designs, but builders and engineers have begun to debate whether its advantages outweigh some of its logistical challenges. Some argue that its value has been overstated, while others describe it as a practical and affordable method for building energy efficient homes in remote Alaskan communities. Still others have adapted its design to fit their needs, thus producing new variations of the design, while also showing how the design of this building system might be reimagined. A deep dive into this debate provides an opportunity to analyze how both knowledge building and moral stances inform the ways that engineers assume global responsibilities related to communities affected by climate change. Drawing on three years of ethnographic research among Alaskan engineers, builders, housing advocates, and community stakeholders, this case study reflects what design scholars describe) as the “moralization of technology” through engineering practices (Verbeek 2006: 269). From this perspective, engineering systems may take on multiple meanings and applications, including marking differences in thought, creativity, and moral affinity among experts who are working to addressing affordable housing needs in Alaska. Reflecting on these differences in perspective, this paper tracks the “cultural biography” of this engineered system across time, place, and institutional, cultural, and geographic settings to probe how debates about the efficacy of this prefabricated system come to index varying moral stances and value systems that are deeply qualitative but also very much a part of the technical and materializing processes of the building design (Kopytoff 1986). As a case study, this analysis also can serve as a teaching tool in engineering and interdisciplinary classrooms for examining the integrative nature of ethics and technology as related to a range of human impacts on the environment and marginalized communities. 

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3. Thermal Impacts of Air Cavities Associated with Insulated Panels Deployed for Exterior Building Envelope Assemblies

   https://doi.org/10.3390/en18133573  

   Dahal, Utsav; Krarti, Moncef (July 2025, Energies)

   MDPI (Ed.)

   This paper presents a comprehensive investigation to evaluate the impacts of air cavities between existing walls and insulated panels on the overall R-values of the retrofitted building envelope systems, addressing a key challenge in exterior envelope retrofitting. The effects of several factors are considered including the air cavity thickness (ranging from 0.1 cm to 5 cm), airflow velocity (varying between 0.1 m/s and 1 m/s), and surface emissivity (set between 0.1 and 0.9), in addition to the thickness of the insulated panels (ranging from 1 cm to 7 cm). It is found that any increase in the air cavity thickness increases the overall R-values of the building envelope assemblies when air is trapped within the sealed cavity. However, when air convection is prevalent, the overall R-value of the retrofitted walls decreases with any increase in air velocity and air cavity thickness. For sealed air cavities, the analysis results show a 9% improvement in R-value of the retrofitted walls. However, the R-value of retrofitted walls with unsealed air cavities can degrade by 76% and 81% for natural and forced air flows, respectively. Emissivity adjustment is found to be the most effective in improving the thermal performance of building envelopes with sealed air cavities, increasing the R-value of retrofitted walls by 13.6% when reduced from 0.9 to 0.1. 

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4. Decision-Making Approach to Urban Energy Retrofit—A Comprehensive Review

   https://doi.org/10.3390/buildings13061425  

   Shu, Lei; Zhao, Dong (June 2023, Buildings)

   This research presents a comprehensive review of the research on smart urban energy retrofit decision-making. Based on the analysis of 91 journal articles over the past decade, the study identifies and discusses five key categories of approaches to retrofit decision-making, including simulation, optimization, assessment, system integration, and empirical study. While substantial advancements have been made in this field, opportunities for further growth remain. Findings suggest directions for future research and underscore the importance of interdisciplinary collaboration, data-driven evaluation methodologies, stakeholder engagement, system integration, and robust and adaptable retrofit solutions in the field of urban energy retrofitting. This review provides valuable insights for researchers, policymakers, and practitioners interested in advancing the state of the art in this critical area of research to facilitate more effective, sustainable, and efficient solutions for urban energy retrofits. 

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5. Seismic and Durability Assessment of Externally Bonded FRP Retrofits in Reinforced Concrete Structures After 2018 Anchorage, AK Earthquake

   https://doi.org/https://doi.org/10.1007/978-3-030-88166-5_106  

   Milev, Sandra; Ahmed, Shafique; Hassan, Mariam; Sattar, Siamak; Goodwin, David; Tatar, Jovan (November 2021, CICE 2021: 10th International Conference on FRP Composites in Civil Engineering)

   Ilki, Alper; Ispir, Medine; Inci, Pinar (Ed.)

   Externally bonded fiber-reinforced polymer (EBFRP) composites are a cost-effective material used for repair and seismic retrofit of existing concrete structures. Even though EBFRP composites have been extensively utilized over the past 20 years as seismic retrofits, there are few data documenting their performance in a real shaking event or after long-term use on concrete structures. In this study, semi-destructive and non-destructive techniques were employed to evaluate the performance and durability of EBFRP-retrofitted buildings that had experienced the 2018 Cook Inlet Earthquake in Anchorage, AK. The performance of EBFRP was evaluated and documented through photographic evidence. Acoustic sounding, infrared thermography, and bond pull-off tests were utilized to evaluate the quality of bonding between the EBFRP and concrete. EBFRP samples were also collected from building interiors and exteriors for chemical and thermal analysis to evaluate the long-term effects of environmental exposure. Although environmental conditions were found to influence the bond quality between the EBFRP composite and concrete substrate, no major signs of earthquake damage to the building components retrofitted with EBFRP were noted. Materials characterization results demonstrated no evidence of polymer matrix degradation in exterior EBFRP samples. 

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