Retrofit Costs Research Articles

Environmental Impact Analysis of Functional Retrofitting Measures in Buildings

A large number of existing building stock in India was built before the implementation of government guidelines mandating the Green Building Codes. These buildings have been operating with various inefficiencies pertaining to their resource consumption and emissions. Literature suggests that the option of functional retrofitting of building has a potential to reduce this inefficiency by up to 50%. This paper investigates this potential by analysing actual cases of functional retrofitting of buildings (for achieving greater operational efficiency) in Indian context. The environmental impact analysis in this study includes the impact categories of primary energy demand, global warming potential, abiotic depletion potential, ozone depletion potential and water resource consumption for both pre-retrofit and post-retrofit scenario of building. The results are then correlated to the initial cost of functional retrofitting for each case in order to identify the inter-relationship and trend with respect to the level of intervention opted for the cases.

Evaluation of a strengthening approach for existing RC buildings in terms of resilience and cost efficiency

The aim of the present study is to assess the performance of a reinforced concrete (RC) building been retrofitted with a new precast insulated steel and concrete composite sandwich wall. The applied retrofitting method, as well as the selection of the performance level for design have been studied with reference to their impact on the retrofit cost and the estimated cost due to possible earthquake losses. As a case study an existing 8-story RC building has been selected that is strengthened with inverted-V steel bracings as well as with the application of the proposed insulated composite walls, respectively. By applying inelastic dynamic analyses with artificial accelerograms scaled to represent earthquake scenarios with specific probabilities of recurrence, the seismic response of the strengthened structure is defined for each scenario. The results of the aforementioned analyses are being correlated with the earthquake losses based on an established methodology. Eventually, the performance of each retrofit method is determined and then compared with the respective performance of the existing building. The most efficient method is defined by considering both the construction cost and the earthquake losses cost of each earthquake scenario.

Long-term sustainability and resilience enhancement of building portfolios

The role of community building portfolios in socioeconomic development and the growth of the built environment cannot be overstated. Damage to these structures can have far-reaching consequences on socioeconomic and environmental aspects, requiring a long-term perspective for recovery. As communities aim to enhance their resilience and sustainability, there is a cost burden that needs to be considered. To address this issue, this paper proposes a community-level performance enhancement approach that focuses on optimizing the long-term resilience and sustainability of community building portfolios, taking into account recurrent seismic hazards. A Gaussian process surrogate-based multi-objective optimization framework is utilized to optimize the cost objective while considering performance indicators for resilience and sustainability. The proposed framework involves using performance-based assessment methods to evaluate the socioeconomic and environmental consequences under stochastic and recurrent seismic hazard scenarios. These evaluated indicators are then used to efficiently optimize the community resilience and sustainability, taking into account the retrofit costs. Finally, approximate Pareto-optimal solutions are extracted and utilized for decision-making. In summary, this paper presents a novel approach for optimizing the long-term resilience and sustainability of community building portfolios by considering recurrent seismic hazards. The proposed framework incorporates performance-based assessment methods and multi-objective optimization techniques to achieve an optimal balance between cost, resilience, and sustainability, with the ultimate goal of enhancing community well-being and decision-making in the face of seismic hazards.

Data driven economic scenarios for retrofitting residential buildings in a northern Italian region

European directives and strategies, such as the ‘European Green Deal’ and the ‘Ren-ovation Wave’, point out the importance of the building sector in achieving the climate goals set by the European Union for 2050. However, a higher renovation rate for the existing buildings is required to achieve these goals. Many barriers prevent the renovation rate from growing. Regarding financial barriers, the long payback times of renovation interventions and the high risk perceived by the potential investors make the renovation rate remain low. Based on data from energy performance certificates, this research proposes a data-driven method to create economic retrofit scenarios for residential buildings using Artificial Intelligence techniques and Monte Carlo simulations. Namely, energy savings have been predicted using an Artificial Neural Network on clusters of residential buildings and the Life Cycle Costs forecasted by Monte Carlo simulations taking into account the uncertainty in many of the inputs. Results obtained by applying the method to a region in northern Italy illustrate two scenarios for the energy retrofit of the built environment, one assuming a payback time of fifteen years and the other of twenty-five years. In both cases, the maximum allowable investment, which varies according to the specific characteristics of the buildings, is much lower than the retrofit costs recorded in the same area in recent years.

A Multi-Stage Decision Framework for Optimal Energy Efficiency Measures of Educational Buildings: A Case Study of Chongqing

Buildings consume large amounts of energy resources and emit considerable amounts of greenhouse gases, especially existing buildings that do not meet energy standards. Building retrofitting is considered one of the most promising and significant solutions to reduce energy consumption and greenhouse gas emissions. However, finding suitable energy efficiency measures for existing buildings is extremely difficult due to the existence of thousands of retrofit measures and the need to meet various objectives. In this paper, a multi-stage decision framework, including a multi-objective optimization model, and a ranking method are proposed to help decision-makers select the optimal energy efficiency measures. The multi-objective optimization model considers the economic and environmental objectives, expressed as the retrofit cost and energy consumption, respectively. The entropy weight ideal point ranking method, an evaluation and ranking method that combines the entropy weight method and ideal point method, is adopted to sort the Pareto front and make a final decision. Then, the proposed decision framework was implemented for the retrofit planning of an educational building in Chongqing, China. The results show that decision-makers can quickly identify near-optimal energy efficiency measures through multi-objective optimization and can select suitable energy efficiency measures using the ranking method. Moreover, energy consumption can be reduced by building retrofitting. The energy consumption of the case building was 64.20 kWh/m2 before retrofitting, and the value can be reduced by 6.79% through retrofitting. Furthermore, the reduction in building energy consumption was significantly improved by applying the decision framework. The highest value of energy consumption was 59.84 kWh/m2, while the lowest value was 27.11 kWh/m2 when implementing the multi-stage decision framework. Thus, this paper provides a useful decision framework for decision-makers to formulate suitable energy efficiency measures.

Construction Cost Decomposition of Residential Building Energy Retrofit

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.

Improving Project Performance Based on Building Information Modelling 6D & LCCA in High-Rise Office Building

Of the total 5.9 million existing buildings, the Office occupies the 2nd position of the most types of buildings with 16% of the Total Total. The least used aspect of BIM (Building Information Modeling) is the ability to obtain building energy models using the 6D BIM methodology. This digital information model is to simulate building energy and improve building energy systems. In this way, 6D BIM simulation allows us to make building design and operational decisions. In the case of increased energy, which leads to greater quality and comfort in the sustainable use of buildings. This issue has a special relationship in public buildings. Where energy efficiency and comfort are two fundamental criteria that are highly valued by society. Once the building's energy model is prepared, it will study and identify possible ones to improve energy efficiency, as well as analyze the incorporation of other, more efficient forms of renewable energy such as the use of natural light. From this research, "10 factors that affect cost performance in Office Building Projects" Maintenance costs, Use of Photovoltaic Solar Panel Materia, Model Obyetifiability, Office Equipment (TV, Computer, Printer etc.), Use of refrigen without ODP, Use of Elevators, Initial cost of retrofit, Materia Façade, Environmentally friendly materials.

The Use of Normative Energy Calculation beyond the Optimum Retrofit Solutions in Primary Design: A Case Study of Existing Buildings on a Campus

There are significant differences between expectations and fulfillment in the building delivery process. Many researchers have emphasized the need for design strategies that establish a direct correlation between design proposals and building performance. One of the main objectives is to support performance-driven primary design, which occurs before the design performance modeling (DPM) phase. To achieve this, a case study of retrofitting existing buildings on campus is presented. A normative calculation approach is used to identify the optimal combinations of a dozen retrofit strategies based on the Energy Performance Calculator (EPC) model. This approach reduces or eliminates the impact of parametric uncertainties on modeling assumptions and simplifies calculations, particularly in restrictive studies. These retrofit solutions involve structural and functional zoning renovation, meaning that disparity between expectations and fulfilments is considered, and a timely related information feedback route to architects is achieved. In the first step of the narrative development of the EPC model, EPC-Calib was used to find the optimal combination of input variables in the model that satisfies the desired target and complies with the problem constraints. Secondly, the retrofit study was implemented with EPC-TechOpt, and 16 retrofit solutions for three design performance models were examined based on the local climatic conditions, building features, and retrofit costs. Finally, design schemes were determined, and the cost-optimal mix of the measures was desired with a 40% energy saving.

Uncertainty-based optimal energy retrofit methodology for building heat electrification with enhanced energy flexibility and climate adaptability

To reach net zero emissions by 2050, the UK government relies heavily on heat degasification in buildings by using heat pump technology. However, existing buildings may have terminal radiators that require a higher operating temperature than what heat pumps typically provide. Increasing the size of radiators and thermally insulating building envelopes could be a potential solution, but the feasibility of these practices is uncertain due to space constraints and high retrofit costs. This study investigates the feasibility and potential benefits of incorporating air-source heat pumps into existing gas boiler heating systems to meet heating demands. The proposed probabilistic optimal air-source heat pump design method enhances energy flexibility and climate adaptability, taking into account a wide range of uncertainty sources and multiple flexibility services (e.g., energy and ancillary services). Heating systems of three educational buildings at the University of Cambridge are used as a testbed to assess and validate the effectiveness of the proposed method, under future climate scenarios and projected decreases in heating demand due to climate change. Results indicate that the best retrofit alternative of the hybrid heating system reduces carbon emissions by 88%, total costs by 54% over its lifespan, and has an average payback period of around 3 years. Air-source heat pumps can meet the majority of the heating demand (around 80%) with gas boilers used for “top-up” heating during high demand. Furthermore, air-source heat pumps' design capacity can fulfil future cooling demand even if retrofit optimization is initially focused on meeting heating needs.

Do housing rental and sales markets incentivise energy-efficient retrofitting of western Germany’s post-war apartments? Challenges for property owners, tenants, and policymakers

A post-World War 2 building boom in western Germany (the original Bundesrepublik) produced a cohort of some 8 million apartments, built in 1946–1979, that are relatively homogeneous in design and materials. On average, these apartments are very energy-inefficient, consuming around 147 kWh of heating energy per square meter of floor area per year (kWh/m2/y). Retrofitting them to about 50 kWh/m2/y is necessary to meet Germany’s climate goals. Considerable skill and infrastructure have developed to attempt to achieve this, but it is expensive. This study investigates whether sales and rental markets disincentivise property owners from retrofitting these apartments to high energy efficiency standards. Data from sales and rental advertisements in 2019–2021 in Germany’s largest online housing advertisement portal, Immoscout24, were used to estimate market sales and rental premiums for energy efficiency in these apartments. For property owners who retrofit apartments then sell them, sales premiums for energy efficiency generally fail to compensate for the retrofit costs, unless the renovation is subsidised. Meanwhile, for purchasers, the reduction in energy costs due to higher energy efficiency does not compensate for the higher purchase price. Likewise, for landlords/landladies who retrofit apartments then rent them out, the rental premiums due to higher energy efficiency are nowhere near sufficient to compensate for the retrofit costs. Tenants, however, can often offset the rental premium through energy savings. In all four cases, there is regional variation. Based on a detailed investigation of this market for energy efficiency, this study suggests specific policy interventions to compensate for these market anomalies.

The collaborative pollutants and carbon dioxide emission reduction and cost of ultra-low pollutant emission retrofit in China's cement kiln

Promoting the ultra-low pollutant emission retrofit of the cement industry, as the third largest industry in terms of air pollutants and carbon dioxide (CO2) emissions in China, has become an important part of achieving carbon peaking and carbon neutrality. In this work, the current status of pollutant emission in cement industry and the pollutant emission limit value of ultra-low emission retrofit in typical provinces were analyzed. And, the collaborative air pollutants and CO2 emission reduction potential and cost-benefit were assessed in six types of ultra-low pollution emission retrofit scenarios. The results indicate that the emission reduction of particulate matter (PM)，sulfur dioxide (SO2) and nitrogen oxides (NOx) in six scenarios are 10%–15%, 1%–5% and 26%–64%, respectively. The construction investment of 43.8 billion Yuan is needed to complete the retrofit of production lines when the pollutant emission limit value is set as 10 mg/m3, 35 mg/m3 and 50 mg/m3 for PM, SO2 and NOx, which is 6 times of that when the pollutant emission limit value is set as 10 mg/m3, 50 mg/m3 and 100 mg/m3. However, the cost per unit equivalent of pollutant abatement of the former is only 36% of the latter. The emission reduction potential of CO2 in six scenarios is 0.4%–0.6%, indicating that the ultra-low pollutant emission retrofit in cement kiln has limited effect on CO2 emission reduction potential. Comprehensive analysis of emission reduction potential and cost-benefit, it is more economical and reasonable for China cement kilns to choose the path of ultra-low emission retrofit in scenario 4.

Empirical predictive model for seismic damage and economic losses of Italian school building heritage

Schools should be safe places where children and young people are hosted during their training years to develop their abilities and skills and to receive an education that makes them prepared to become the future of the nations where they live. Even though these aspects are of paramount importance and widespread recognized, the same importance does not seem to be equally ensured to school facilities. Educational institutes, indeed, are often old and realized without recent safety Standards, becoming consequently non-resilient, nor robust structures towards multiple natural hazards. This aspect concerns lots of countries worldwide, without making distinction among their richness level.In this paper empirical models for the prediction of damage and retrofit costs expected after earthquakes are presented. These probabilistic models relate seismic intensity to expected damage and economic losses, through the definition of continuous indexes, and are based on data collected after a recent earthquake occurred in Central Italy. Empirical data, required to define the probabilistic models, have been obtained by combining information coming from shaking maps, provided by the National Institute for Geophysics and Volcanology (INGV), information on the building properties (e.g. locations, dimensions, construction typology), provided by the Ministry of Education, and data about the damage suffered by constructions and funding for retrofit actions including damage repairing and seismic upgrading, provided by the Reconstruction Office. Proposed models provide the opportunity to directly derive fragility curves, to make it possible the use of the research outcomes in risk frameworks based on a discrete description of the damages and losses.Model parameters have been calibrated for the considered set of available data, but the methodology is general and can be also applied to different contexts, given data are available. Finally, the proposed models have been used to simulate the post-earthquake damage and losses scenario following a seismic event. A proposal for the analyses of probabilistic outputs have been developed to provide information useful to decision making purpose.

A multi-objective decision-making framework for implementing green-grey infrastructures to enhance urban drainage system resilience

Green-grey infrastructures implementation for addressing urban flood damages and urban drainage system’ (UDS) resilience (respectively) needs comprehensive evaluation under various planning and design influencing factors. In this paper, a multi-objective decision-making framework is developed for the optimization of green-grey infrastructures to understand the trade-off between benefits and retrofit costs under various design configurations, rainfall intensities, and system performance indicators. In the developed framework, the grey infrastructure locations are optimally determined by using Analytic Hierarchy Process (AHP) method with three defined indicators (e.g., flood volume and flood duration of flooding nodes, sensitivity of flooding nodes) and maximum percentage of each type of green infrastructure (GI) in each sub-catchment based on land-use analysis as a preliminary step of the multi-objective optimization process, followed by decision-making procedure. The application results reveal that optimal designs of grey infrastructure are more cost-effective and may have a significant influence on the reduction of flood damages and outlet peak flow compared to GI from their individual evaluations, while GI improves UDS’ functionality performance indicators (e.g., resilience, reliability, and sustainability) better than grey infrastructure. However, a combined implementation of both infrastructures boosts their advantages because of the synchronization effect compared to individual scenarios, providing the most cost-effective optimal UDS designs. Moreover, the cost-effectiveness of coupled green-grey infrastructures designs could be enhanced from lower to higher design storms because of higher rate of utilization of stormwater infiltration and storage capacities of both infrastructures. The framework presented in this study can be conveniently generalized to other case-studies for optimal implementation of green-grey infrastructures as long as including their local economic parameters, climatic patterns, urban development plans and green-grey infrastructures design guidelines.

Assessing Fatigue Damage in the Reuse of a Decommissioned Offshore Jacket Platform to Support a Wind Turbine

AbstractAn offshore energy transition, even if only a gradual one, from carbon-emitting fossil fuel extraction to cleaner sources is recommended, if we are to slow the harmful impacts of climate change. The potential for sustainable reuse of decommissioned offshore jacket platforms to support wind turbines is being considered as an attractive proposition in such a transition. To maximize the benefits of such reuse of assets, what is needed is a rational optimization strategy that considers the remaining life of a repurposed platform, associated retrofit and construction costs, and a future period of gross renewable energy generation following installation of the wind turbine. We outline a study that employs a fatigue reliability-based framework, based on the global fatigue approach and Palmgren–Miner’s rule, to aid in such sustainable reuse planning and optimization. The framework proposed identifies an optimized reuse plan that incorporates metocean data analysis, structural analysis, life cycle evaluation, and revenue optimization. We employ a case study and sustainable reuse scenario for a site in the vicinity of Porto (Leixões), Portugal.

Sustainability-Oriented Optimization and Decision Making of Community Buildings under Seismic Hazard

Optimization and decision-making tools are often utilized to enhance the performance of community buildings under extreme events, but this may compromise the ability of future generations to enhance performance. Hence, a sustainability-oriented approach is required to enhance the performance of community buildings under extreme events. In this context, this paper proposes an optimization and decision-making framework considering multiple performance indicators, including socioeconomic and environmental consequences as well as retrofit costs. These performance indicators are assessed by utilizing performance-based assessment methodologies in terms of sustainability dimensions. The performance indicators are then exploited as multiple performance objectives in a genetic optimization to determine the Pareto optimal solutions. Finally, the Pareto optimal solutions are utilized for decision making to extract ideal solutions for the given retrofit costs. The ideal solutions provide trade-offs between the consequences of extreme events and the retrofit costs required to reduce the consequences of extreme events.

A Cost–Benefit Analysis Framework for City-Scale Seismic Retrofitting Scheme of Buildings

To improve urban seismic resilience, a reasonable seismic retrofitting scheme for buildings is required. Urban cities contain a large number of buildings, making it challenging to precisely assess the seismic retrofitting benefits of each one. This paper proposes a cost–benefit assessment framework that takes into account seismic risk, seismic damage, retrofit costs, economic losses, and cost–benefit analyses for the city-scale seismic retrofitting of buildings. The proposed framework adopts readily available building parameters, including the number of stories, construction year, total height, structural type, floor area, and response spectrum for structural design. It makes use of empirical seismic retrofitting models and a newly developed story-level seismic loss assessment method combining the physical mechanism and empirical loss ratios. For city-scale cost–benefit analysis, the framework can strike a good balance between data accessibility, computational workload, level of result details, and result accuracy. It can adapt nimbly to earthquake-induced indirect losses and budgetary constraints on retrofitting. The analysis of 98,618 buildings in Xi’an city, China, is carried out. The findings indicate that, when potential indirect economic loss ratios of buildings are neglected, the retrofitting benefits of unreinforced masonry and old buildings are the most significant.

Affordability assessment of passive retrofitting measures for residential buildings using life cycle assessment

Climate change impacts have been increasingly noticeable worldwide, especially as energy concerns have increased. Because buildings consume significant amounts of energy, sustainably retrofitting existing buildings has become essential. However, several countries are pretty concerned about the affordability of retrofitting and energy conservation measures. Therefore, this research assesses the affordability of selected passive heating and cooling retrofitting strategies using the residual approach methodology. Specifically, this work studies the effects and efficiency of retrofitting the residential buildings in Irbid, Jordan, through life cycle analysis, where dynamic thermal simulation (IES-VE) is employed. This strategy determines the required heating and cooling loads, the life cycle carbon dioxide emissions, and the economic feasibility of retrofitting using the Net Present Value methodology. The results show that passive building retrofitting can generate considerable economic and environmental benefits. Additionally, the affordability assessment reveals that retrofitting measures are affordable for 73–78% of Jordanian households. Furthermore, retrofitting makes the energy required for building conditioning affordable for 82.8–85.8% of households. This affordability assessment proved that the initial investment cost of retrofitting is the major obstacle to implementing it, especially for low-income households, despite the long-term economic and environmental benefits of this process. Thus, governmental financial support for the retrofitting projects would support achieving the sustainable development goals and mitigating climate change impacts.

Urban Heat Transition in Berlin: Corporate Strategies, Political Conflicts, and Just Solutions

In the field of urban climate policy, heat production and demand are key sectors for achieving a sustainable city. Heat production has to shift from fossil to renewable energies, and the heat demand of most buildings has to be reduced significantly via building retrofits. However, analyses of heat transition still lack its contextualization within entangled urban politico-economic processes and materialities and require critical socio-theoretical examination. Asking about the embeddedness of heat transition within social relations and its implications for social justice issues, this article discusses the challenges and opportunities of heat transition, taking Berlin as an example. It uses an urban political ecology perspective to analyze the materialities of Berlin’s heating-housing nexus, its politico-economic context, implications for relations of inequality and power, and its contested strategies. The empirical analysis identifies major disputes about the future trajectory of heat production and about the distribution of retrofit costs. Using our conceptual approach, we discuss these empirical findings against the idea of a more just heat transition. For this purpose, we discuss three policy proposals regarding cost distribution, urban heat planning, and remunicipalization of heat utilities. We argue that this conceptual approach provides huge benefits for debates around heat transition and, more generally, energy justice and just transitions.

The 2012 Greek Retrofit and Borrowing Costs in the European Periphery

The 2012 Greek Retrofit and Borrowing Costs in the European Periphery

Seismic vulnerability assessment and retrofitting design of Italian public buildings

Rina Consulting, between 2019 and 2021 was involved in the seismic vulnerability assessment and retrofit design of a large public buildings stock in Italy. The project includes several buildings built between the 40′s and the 90′s located in regions prone to very high seismic hazard and characterized by strategic uses. The buildings included in the portfolio span from masonry structures to reinforced concrete structures, including precast buildings. All the structures were submitted to linear and nonlinear analysis to define their seismic vulnerability and identify their structural deficiencies; then a retrofit design was performed to guarantee the increase of the building's seismic capacity according to the requirements of National code. Alternative retrofitting scenarios were investigated, and compared by means of cost-benefit analysis, with the aim to guarantee a good balance between the costs and the structural efficiency of the interventions.The main aim of the paper is to present practical considerations regarding the main issues related to the data gathering, the seismic input definition and the seismic vulnerability index obtained for the different building typology. The study aims also to investigate the comparison between the seismic requirements assumed for the original design and the seismic requirements assumed for the seismic vulnerability according to the current national code and its influence on retrofit interventions costs. The collected data form part of a database which scope is to provide a criterion for predicting retrofit strategy and costs as a function of the seismic vulnerability index. Final purpose of the study is to provide possible improvement of the methodologies to be applied to similar projects that include large building stock to define a possible efficient framework to be proposed to the different stakeholders.