Building Retrofit Projects Research Articles

Advanced Decision- Making Framework for Sustainable Energy Retrofit of Existing Commercial Office Buildings

In the background of rising global initiatives to combat climate change and promote better energy management, retrofitting of current structures has become a major strategy. This abstract and literature review aims at presenting a full review of a decision-making approach that can be used in choosing sustainable options for energy retrofitting. This particular framework is designed to help guide retrofit decision-making due to the many issues that surround the process by providing an economic as well as an environmental and social context. Energy retrofitting means improving the existing structure or complex to decrease its energy intensity and have a negative impact on the environment. As stated earlier, it is a critical process for attaining sustainability goals and advancing the performance of buildings. But the decision on which retrofit measures should be implemented can be rather difficult because of the availability of a vast number of technologies and because more factors must be considered, such as cost and energy savings. The decision-making framework provided in this article aims at categorizing retrofit selection into this list of features and views the current article as a way of making the process more efficient. It encompasses the life-cycle cost analysis (LCCA), the economic valuation, and the multi-criteria decision analysis tools and criteria. These tools facilitate the evaluation of financial viability, the advantages of climatically retrofitting, and the environmental effects of distinct retrofitting choices. The above-mentioned framework is exemplified with a case study of an office building retrofit project. The following case includes an example of the application of the mentioned framework and illustrates the explanation of how it helps to make decisions. Due to the consideration of costs, energy, and environmental performance, the framework enables the stakeholders to choose appropriate retrofit measures. Other than the case study, the framework also focuses on the need to establish a sustainable energy retrofit DSS. Thus, the DSS supplements collected data on building performance, retrofit technologies, and economic aspects, which can be accessed by the stakeholders in real-time and with built-in facilities for scenario analysis. This system improves decision-making since retrofit results can be monitored and evaluated frequently. Both tools and strategies for the decision-making of sustainable energy retrofits bring a logical and systematic approach aimed at neutralizing the decision-making challenges related to retrofit selection. By applying economic, environmental, and social factors in the decision-making process, the framework assists the stakeholders in reaching energy efficiency and sustainability goals. The development of another strong decision-support system also improves the working of the framework and checks that retrofit projects are done efficiently and are strategic to the general goal of sustainable development.

Meta learning regression framework for energy consumption prediction in retrofitted buildings: A case study of South Korea

Building energy consumption (BEC) prediction is crucial for optimizing energy efficiency in building retrofit projects, particularly during the early design phase. However, existing machine learning (ML) models often face challenges with overfitting and complexity, limiting their accuracy and generalizability. This study addresses these issues by proposing a novel meta-learning regression framework for energy prediction in green retrofitted buildings. The framework employs optimized base regressors using various ML models and integrates them through stacking regression to enhance predictive accuracy and generalization. The model’s performance is evaluated against advanced methods like Deep Neural Networks and Ensemble Learning Regression using data from over 811 green retrofitting projects in South Korea. The proposed method demonstrates superior efficiency, achieving the lowest mean absolute error (19.899 for Primary Energy Consumption and 11.301 for Energy Required Amount), lowest root mean squared error (29.494 for Primary Energy Consumption and 19.977 for Energy Required Amount), and highest R-squared score (0.786 for Primary Energy Consumption and 0.542 for Energy Required Amount). This research contributes a novel approach to ensemble modeling for BEC prediction, showcasing its superior accuracy, generalizability, and practical applicability in the context of green building retrofits.

An ontology-based tool for safety management in building renovation projects

Managing deep renovation projects is challenging due to the interactions with their surroundings, the issues of limited access and space, and the uncertainty around the composition and conditions of existing buildings. The interplay between the building areas, the building elements involved in the deep renovation, and the renovation scenarios and activities present challenging situations for managing safety risks. Research on enhancing safety in building projects using digital approaches such as BIM has mainly focussed on new construction works, yet limited research is available for deep building renovation projects. Using a Design Science Research (DSR) methodology, this paper develops an ontology for representation and identification of hazards in deep building renovations, instantiates the ontology through the development of a digital tool, and demonstrates its usefulness in hazard representation and identification by performing tests with real industry data from deep renovation projects, as part of a Horizon Europe 2020 research project, called RINNO. The testing involved a multi-residence apartment case study and three different renovation scenarios and successfully demonstrated the ability to automatically identify potential hazards relating to a particular renovation strategy. While the proposed ontology can be used to reduce the risk of accidents and injuries in building retrofit projects, its main implication is in laying the foundation for future digitally enabled approaches for managing safety in building renovation projects.

Towards Achieving Zero Carbon Targets in Building Retrofits: A Multi-Parameter Building Information Modeling (BIM) Approach Applied to a Case Study of a Thermal Bath

As the urgency to mitigate climate change intensifies, the achievement of zero carbon targets in the built environment has become a critical objective. Building retrofitting plays a vital role in reducing energy consumption and carbon emissions in existing buildings. This paper presents an approach that combines Building Information Modeling (BIM) with multiple domains to strive for zero carbon targets in building retrofit projects. The proposed approach is based on a dynamic multi-parameter analysis that integrates indoor comfort, energy savings, CO2eq reduction, and the social cost of carbon while considering investment costs. Renewable energy technologies, such as photovoltaic panels and solar thermal systems, are emphasized to achieve the desired zero-carbon outcomes. Real-time monitoring mechanisms enable continuous performance evaluation and adaptive retrofit strategies for further energy savings. This approach is validated through a case study of an existing thermal bath building, known as “Terme Lucane”, located in southern Italy. The results of the study demonstrate significant reductions in energy consumption and carbon emissions, highlighting the potential of the proposed approach to achieve zero carbon targets through the integration of multi-data BIM implementation. These findings offer a promising pathway for building retrofit projects aiming for zero carbon targets through multi-data BIM modeling.

Development of an optimization model for decision-making in building retrofit projects using RETROSIM

ABSTRACT Nearly-zero energy buildings are standard for new constructions in the European Union. The challenge for decarbonized cities is retrofitting the existing buildings. Retrofitting the existing buildings provides considerable opportunities for improving occupants’ comfort and reducing global energy consumption and greenhouse gas emissions. Building retrofit is being considered one of the main approaches to achieve sustainability in the built environment at relatively low-cost and high-uptake rates. Although a broad range of retrofit technologies are readily available, methods to ascertain the most suitable set of retrofit actions for specific projects are still a practical challenge. This article first aims to develop and present a simulation-based multi-objective optimization model, named RETROSIM, to quantitatively assess technology choices in a building retrofit project. RETROSIM is a combination of a building energy simulation model and RETROSIM proprietary optimization engine. Secondly, in this study, RETROSIM is used to evaluate a building retrofit project as a case study to show the functionality of the proposed method. The study initiates with the single optimization of objective functions focusing on the building’s characteristics and performance: primary energy consumption, global costs and thermal discomfort hours. Then this methodology is used to study the interaction between these conflicting objectives and evaluate their trade-offs.

Extending urban energy transitions to the mid-tier: Insights into energy efficiency from the management of HVAC maintenance in ‘mid-tier’ office buildings

Older, smaller and poorer quality commercial buildings (the ‘mid-tier’) make up much of the commercial building stock and are crucial for urban energy transitions. Action must extend beyond new commercial buildings and high-end building retrofit projects to realise deep decarbonisation of the built environment. Mid-tier buildings offer substantial opportunity for energy retrofits, though the sector lags behind premium office buildings. Comparatively, different ownership structures, tenant profiles, and facilities management regimes challenge the value-proposition for energy transition, and little is known about how to leverage energy performance improvements in this crucial sector. Focussing on the management of heating, ventilation and air-conditioning (HVAC) systems as an entry point for improvement, this paper presents empirical evidence from the largest survey conducted with Australian HVAC contractors, facility managers, and system engineers to date. The results explicate the realities of managing energy in mid-tier office buildings in Australia as a socio-technical undertaking. Our analysis identifies limits and opportunities for shaping energy efficiency of HVAC maintenance, focussed on issues pertaining to workforce, building and systems, and maintenance practices. Further, we draw out policy imperatives needed to address hurdles created by multiple market failures that complicate energy transition in mid-tier buildings.

Comparison of Various Types of Seismic Hazard Assessment and their Influence on Structural Vulnerability

This work sought at enhancing techniques for the assessment of seismic risk in order to understand displacement effects and impacts of different seismic hazard estimation techniques on structural vulnerability. The analysis is useful because the number of earthquakes around the world is on the rise, and there is a necessity to eliminate the potential threat. Weighted Average of Ground Motion intensities was used to determine hazard parameters, along with PSHA and DSHA. The information regarding seismicity was collected from the regional networks and catalogs with the help of geotechnical investigation for site characteristics. An assessment of structural resilience was accomplished with building inventories and retrofit projects data with the help of FEA for computational modeling. The degree of earthquake was recorded to be from 4. 5 to 7. 5 Mw, with PGA ranging from 0 to 0. 2 to 0. 3g. During preliminary screening, Sites were ranked into high PSA and low PSA divides as well as Low Seismic Hazard and Medium to High Seismic Hazard. These retrofitting measures such as base isolation and strengthening further improved performance of buildings, in that they reduced peak drift ratios by up to 50% and, base shear force capacity by 30% of average value. The Effectiveness Index of retrofitting work varied from 0. 732 to 0. 912, from which one can draw the conclusion concerning appreciable enhancements of earthquake resistance. The study thereby laid a foundation to prove that it is possible to reduce the seismic risk by using the advanced hazard analysis methods and based on these analyses, some systematic retrofit interventions are effective enough in achieving the objective of sustainable urban development. The conclusions derived in this paper present quantitative information relevant for understanding actions toward earthquake prevention in vulnerable territories.

Sustainable building retrofit model for high-rise, high-density city: a case in Hong Kong

Considering the significant consumption of energy in existing building stocks, effective retrofitting has great potential for reducing such consumption and promoting sustainability in existing buildings. This study aims to develop a sustainable retrofit decision-making mechanism for high-rise buildings in Hong Kong, China, by uncovering the optimum set of retrofit solutions based on the local climatic conditions, building features and cost. Based on a prototype building in Hong Kong, the study employed the net present value (NPV) to unveil the most suitable solutions to maximise the energy efficiency of existing buildings and minimise their retrofit costs, integrating the energy simulation. This study revealed that it is desirable to adopt an optimal set of measures for achieving a 40% energy improvement since the energy conservation can be as much as 82 (kWh/m2)/year with the optimal NPV of more than US$3300 over a 20 year life span. However, the cooling system, building energy management system and thickness of wall insulation are the most influential factors to the optimum NPV and energy conservation in Hong Kong. The identified optimal set of cost-effective retrofit measures can be effectively implemented for sustainable retrofit projects in the existing building, and the developed methodological framework can be suitably adapted for sustainable building retrofit projects in different climatic zones. The decision-making model is validated by the process of calculating energy consumption, selecting practical retrofit measures and analysing retrofit benefits when taking the local building standards into account.

Factors influencing existing medium-sized commercial building energy retrofits to achieve the net zero energy goal in the United States

ABSTRACT Despite the increased awareness of benefits and opportunities resulting from energy retrofits, there is a lack of information regarding the factors influencing the success of energy retrofits – especially deep energy retrofits – aiming to achieve a net zero energy goal. The aim of this study is to identify factors and variables that could contribute to the successful implementation of energy retrofit measures in buildings with the goal of achieving net zero energy. A database of 34 small- and medium-sized commercial building retrofit projects was developed for this analysis, which was derived from the New Buildings Institute’s Net Zero Energy Building Database. Five factor categories were investigated: physical, technical, environmental, economic, and policy. A total of 11 variables from the 5 categories were analysed. The results show that success stems from a combination of certain variables: the number of floors, the climate zone, and the building cost. In general, the results indicate a trend: compact buildings with a construction cost range between $19/m2 and $42/m2 in a mild climate have a higher likelihood of achieving a net zero energy goal. Also, the analysis provides new evidence toward the importance of understanding a building’s physical characteristics in an existing building energy retrofit.

Barriers to retrofitting buildings for energy efficiency in South Africa

Literature has established the enormity of energy consumed by buildings. The processes involved in generating and distributing this energy, and most especially its usage is identified as causing a significant adverse environmental impact. As a strategy for enhancing the effectiveness and efficiency of existing buildings through the introduction of new technologies, retrofitting has become another avenue for achieving sustainability in the construction industry. This paper, therefore, seeks to identify the major barriers to retrofitting buildings for energy efficiency in South Africa. A structured questionnaire survey was used as the instrument for data collection. Data for the study were gathered from construction professionals (architects, civil engineers, quantity surveyors, project managers, construction managers, and energy engineers) with experience in building retrofit projects. A quantitative approach to data analysis was adopted using percentage, standard deviation, and mean item score. From the data analysed, the results revealed low income, high investment costs, occupant’s resistance, high upfront cost, and low consumer appeal as the top five barriers. The findings from this study will help improve and encourage retrofitting buildings for energy efficiency which is believed to have the potential of drastically reducing the long-term cost of energy consumption, greenhouse gas emissions and carbon footprint.

Analysis of the energy and thermal performance of a radiant cooling panel system with integrated phase change materials in very hot and humid conditions

This study evaluates the energy and thermal performance of a radiant cooling panel system with integrated phase change materials (PCMs) for application in building retrofit projects. The focus is on the energy saving potential of using two different strategies to avoid condensation in very hot and humid climate conditions. The cooling energy consumption of a DOE medium office prototype building model with a conventional all-air system is used as a baseline for comparing the proposed configurations. The results show that the radiant system yielded energy savings of around 48% compared to the all-air system for existing office buildings. Results also show that the proposed system is able to operate only during the night-time, which improves the plant efficiency. Thus, the energy savings are mainly due to a reduction in the energy consumption of the cold generation system and lower energy use for ventilation compared with conventional air systems.

Opportunities for financing sustainable development using complementary local currencies

Financing building retrofit projects that contribute to climate change mitigation has always represented a significant barrier. With 28% of global emissions coming from existing buildings, it is of paramount importance to carry out retrofit measures that lead to significant reduction of these emissions. Whilst this is perfectly possible to achieve with current methods and current technology, there is no sufficient conventional finance to carry out zero carbon retrofit at scale required for climate change mitigation. The article introduces an alternative and sustainable business model that creates new opportunities for financing zero carbon retrofit of buildings. It demonstrates that the value of solar energy falling on roofs of buildings can become a driver for new local economic systems, and discusses the requirements for practical application.

Critical Analysis of in situ Performance of Glass Fiber Core VIPs in Extreme Cold Climate

Glass fiber core vacuum insulation panels (VIPs) are becoming an increasingly attractive option for building envelope construction due to lower cost and availability around the world. Although fumed silica core VIPs have shown superior long-term performance under accelerated aging tests compared to glass fiber core VIPS, these laboratory test results have yet to be verified with long-term field performance data. In 2011, glass fiber core VIPs were installed in a commercial building retrofit project in Yukon, Canada (one of Canada’s most northern territories), and have been continuously monitored since. This paper summarizes the thermal performance of the glass fiber core VIPs over the period of 2011 – 2018 in an extreme cold climate. Findings from this study provided data to validate glass fiber core VIP accelerated aging test results and the aging rate of VIPs in a cold and dry climate was determined. These results will help developing a better understanding of the long-term performance of glass fiber core VIPs in a real-world context.

Cradle-to-grave life-cycle assessment within the built environment: Comparison between the refurbishment and the complete reconstruction of an office building in Belgium

In the current context of the necessary sustainability transition of the built environment, it is widely recognized that buildings are a major contributor to the energy consumption of fossil fuels and the emission of CO2. Most of the debates, policies and research are however dedicated to the sole construction of new very efficient (up to zero-energy) building, neglecting the potential of actions on the existing building stock. In this context, we argue that LCA tools are of a huge interest to objectivise the need to refurbish old buildings, in order to increase their energy efficiency and extend their life span, and to compare this strategy to the demolition/reconstruction of buildings. To achieve this aim, this paper aims at updating an existing tool that enables to carry out the life cycle assessment of buildings, by taking into account demolition and construction phases. Then, the tool is applied to one case study of the low-energy refurbishment of a public office building in Brussels, to compare the impacts of the complete demolition followed by a complete reconstruction (rebuild project) to the retrofitting of the existing building (retrofit project). Our main findings confirm the huge impact of the use phase, highlight the impact (energy and CO2 emissions) of the construction and demolition phases and show that the in-depth renovation of this building leads to lower environmental indicators compared to its full reconstruction. The tool and results provided in this paper support the development of policies in favour of the retrofitting of the existing building stock and highlight the importance of including the whole life cycle of the building in the analysis.

A numerical study of adaptive building enclosure systems using solid–solid phase change materials with variable transparency

Buildings currently consume about 40% of all energy use in the US and therefore play an important role in mitigating global greenhouse gas emissions. Passive solar design strategies can be used to limit building heating and cooling demands. Current passive solar design strategies, however, require substantial design effort for each individual project, often require mechanical and electrical control systems, and the approach is also difficult to implement in building retrofit projects. Solid–solid phase change materials (SS-PCM) are currently emerging as alternative materials for thermal energy storage. Here we present an exploratory study on two innovative climate responsive building enclosure systems that employ the transparency change and latent heat storage capacity of SS-PCMs as mechanisms to passively control building temperature. The first system is based on a thin layer of SS-PCM that is placed on top of a highly reflective film to control solar heat gain. The second system uses a layer of SS-PCM foam to store thermal energy and control heat flow. The performance characteristics of the systems are evaluated using finite element modeling techniques. Simulation results shed light on the synergistic interactions between different components of the systems and indicate that both systems can reduce undesirable heat exchange between the building and its environment if designed properly. Recommendations are made regarding various material and system parameters, including the attenuation coefficient of the SS-PCM, system thickness, void ratio and distribution of the void ratio of the SS-PCM foam based system, and phase transition temperature.

Pre-assessment Method for Historic Building Stock Renovation Evaluation

Energy retrofit of buildings in Europe is one of the main priorities in order to reach its sustainability goals. Every building retrofit project faces with a decision making process attributed to optimal alternative selection depending on the initial retrofit goals. For each building there may be numerous alternatives which have to be objectively evaluated to meet the needs of involved stakeholders. Therefore it is necessary to develop a set of evaluation criteria tailored to each specific building or group of buildings depending on the replicability of retrofit projects. In the case of historic buildings, the decision making process may become increasingly complex. Therefore there is a necessity to introduce scientifically justified criteria, which are most suitable for each specific building retrofit case. In this paper a historic building construction evaluation method is presented, which provides preliminary overview of the condition at which buildings structures are contained. Together with the building space heating energy consumption analysis, this method provides a pre-assessment methodology for prioritising which historic buildings should be selected for renovation.

A numerical and experimental study of a cellular passive solar façade system for building thermal control

About 39% of total energy in the United States is consumed in residential and commercial buildings. Passive Solar Design (PSD) strategies have been successful in reducing building energy consumption, however, they require a substantial design effort for each individual project and are also difficult to implement in building retrofit projects. These characteristics tend to inhibit the widespread use of PSD principles in buildings today. In this paper a building envelop system is presented that incorporates small air cells backed by phase change material. The goal is to achieve quasi-constant core temperatures within a building enclosure system. The proposed technology results in a cladding system that can be used to thermally condition buildings. Initial experimental and numerical research efforts show that the system has significant potential to function properly when exposed to winter conditions. While initial results are promising, the system will require dynamic response to function properly in both winter and summer conditions.

A system for the management of old building retrofit projects in historical centres: the case of Portugal

ABSTRACTThe retrofitting works in old buildings require appropriate knowledge of the vernacular techniques. Previous researches have identified retrofitting works as more intrusive and using more unnecessary demolition materials than real needs. This study constitutes a new framework that focuses on the project management success of old building retrofitting in historical centres by developing a methodological system for this purpose. It uses a construction sector system approach, reviews legal requirements, framework specifications, recommendation practices and sustainable measures adapted to old building projects. It presents 50 parameters adapted to these works’ specificities that could be used by construction market stakeholders. The research uses a case study methodology divided in two parts. The first one involves the review of building retrofitting projects in historical centres, complemented by a questionnaire in the second part. The results of the projects review have shown little concern with th...

An approach for making optimal decisions in building energy efficiency retrofit projects

The study presents an optimization-based decision support approach to determine the optimal energy efficiency retrofit options in existing buildings. The main challenge encountered in the decision-making process of building retrofit projects is the selection of an optimal set of solutions within a wide range of solution space according to multiple criteria. In order to overcome this problem, this study uses an integrated optimization approach by combining both the variance-based sensitivity analysis and optimization methods to maximize energy savings and optimize financial returns in building energy efficiency retrofit projects. The proposed approach was applied to an existing public school building in Izmir, Turkey that represents hot-humid climate to test its validity and performance. The optimizations were performed and results were obtained for three different scenarios whose content was determined based on project objectives and constraints fulfilled by a survey conducted by building users. The case study results indicate that the proposed approach is effective in defining the application order of retrofit options by identifying the most influential parameters for building energy efficiency and finding out the optimal retrofit solutions per multiple criteria.

Evolutionary Multi-objective Optimization in Building Retrofit Planning Problem

Energy efficiency has been a primary subject of concern in the building sector, which consumes the largest portion of the world's total energy. Especially for existing buildings, retrofitting has been regarded as the most feasible and cost-effective method to improve energy efficiency. When planning retrofit in public buildings, the most obvious objectives are to: (1) minimize energy consumption; (2) minimize CO2 emissions; (3) minimize retrofit costs; and (4) maximize thermal comfort; and one must consider these concerns together. The aim of this study is to apply evolutionary multi-objective optimization algorithm (NSGA-III) that can handle four objectives at a time to the application of building retrofit planning. A brief description of the algorithm is given, and the algorithm is examined using a building retrofit project, as a case study. The performance of the algorithm is evaluated using three measures: average distance to true Pareto-optimal front, hypervolume, and spacing. The results show that this study could be used to find a comprehensive set of trade-off scenarios for all possible retrofits, thereby providing references for building retrofit planners. These decision makers can then select the optimal retrofit strategy to satisfy stakeholders’ preferences.