Building Energy Retrofit Research Articles

Green Campus Transformation in Smart City Development: A Study on Low-Carbon and Energy-Saving Design for the Renovation of School Buildings

In the context of increasingly deteriorating global ecological conditions and rising carbon emissions from buildings, campus architecture, as the primary environment for youth learning and living, plays a crucial role in low-carbon energy-efficient design, and green environments. This paper takes the case of Yezhai Middle School in Qianshan, Anhui Province, to explore wind environment optimization and facade energy-saving strategies for mountainous campus buildings under existing building stock renovation. In the context of smart city development, integrating advanced technologies and sustainable practices into public infrastructure has become a key objective. Through wind environment simulations and facade energy retrofitting, this study reveals nonlinear increases in wind speed with building height and significant effects of ground roughness on wind speed variations. Adopting EPS panels and insulation layers in facade energy retrofitting reduces energy consumption for winter heating and summer cooling. The renovated facade effectively prevents cold air intrusion and reduces external heat gain, achieving approximately 24% energy savings. This research provides a scientific basis and practical experience for low-carbon energy retrofitting of other campus and public buildings, advancing the construction industry towards green and low-carbon development goals within the framework of smart city initiatives.

Life Cycle Sustainability Assessment: An Index System for Building Energy Retrofit Projects

As a major contributor to global energy consumption and greenhouse gas emissions, the building sector is crucial in shaping energy and climate change policies. Understanding building energy consumption is essential for developing effective policies, and comprehensive datasets and analyses are increasingly important. This paper outlines a structured methodology for developing a sustainability assessment index for building energy efficiency retrofits throughout a building’s life cycle, covering the design, construction, use, and out-of-use phases. It highlights the interdependencies among these phases, with the design plan influencing energy efficiency and material selection, the construction plan ensuring these goals are met, and the plans for energy management, demolition, and resource recovery focusing on sustainable practices. The keys to energy-efficient retrofits are sustainable materials, energy-efficient equipment, and green technologies, which help reduce energy consumption, emissions, and operating costs. Oversight and regulation are necessary to maintain standards. This research combines a literature review, surveys, interviews, the Delphi method, and an analytic hierarchy process (AHP) to develop a comprehensive evaluation system, categorizing 20 factors across a building’s life cycle and assigning weights based on environmental, economic, and social dimensions. The system provides a scientific basis for assessing the sustainability of energy efficiency programs, validated through consistency testing.

Incentive mechanism and scenario simulation of residential energy-efficiency retrofits – From the perspective of tripartite evolutionary game

Energy-efficiency retrofits (EER) are increasingly becoming a key tool for sustainable building development. Compared to extensive urban renewal, refined building energy retrofits hold more practical value. Of this, the complexities arising from the differences in the claims of multiple stakeholders deserve our attention. However, limited efforts have been made in the existing literature to explore this issue. This paper constructs a tripartite evolutionary game model for residential EER from the perspective of engineering management. Taking a typical building in an old neighborhood in Nanchang, Jiangxi Province as an example, the theoretical model is validated. The results indicate that participants in the residential EER market display varying decision-making behaviors at different developmental stages. The government’s implementation of appropriate punitive measures in the early stages will encourage enterprises to participate in EER. Simultaneously, attention should also be paid to the demands of residents to ensure the smooth progress. Market-based renovation models should be actively promoted, and specific renovation programs should be created to accommodate varying requirements. This paper offers theoretical guidance for decision-making and developing residential EER.

Correction: Examining building energy retrofit effects on indoor environmental quality before the Covid-19 era: a critical assessment

Correction: Examining building energy retrofit effects on indoor environmental quality before the Covid-19 era: a critical assessment

Energy retrofitting of hospital buildings considering climate change: An approach integrating automated machine learning with NSGA-III for multi-objective optimization

In the context of sustainable development, energy-saving renovation of existing buildings can not only effectively reduce energy consumption but also improvement the residential comfort and office environments. This study proposes an optimization method for building energy-saving renovation based on automated machine learning and the NSGA-III algorithm, aiming at efficiently and accurately identifying the best energy-saving renovation schemes. The results showed that automated machine learning could provide a predictive model for multi-objective optimization analysis in a relatively short training time, with an average prediction accuracy of over 95%. And the Stacked Ensemble algorithm and Gradient Boosting Machine algorithm perform the best among all the algorithms considered in this study. Additionally, climate change significantly affects the energy-saving benefits and thermal comfort performance of renovation measures, thereby altering the choice of optimal schemes. The final renovation schemes obtained through the NSGA-III and entropy weight TOPSIS method can achieve an energy saving rate of 22.06% to 26.48% under typical climate scenarios, while also improving thermal comfort time by 31.87% to 43.73%. In future climate scenarios, an energy saving rate of 32.73% to 33.02% and a thermal comfort time of 40.20% to 42.29% can be achieved. Combining these two technologies can quickly and effectively find the best balance among energy consumption, whole life cycle cost, and thermal comfort time. The method proposed in this paper offers new perspectives and tools for researchers in the field of building energy conservation, demonstrating the application potential of automated machine learning and the NSGA-III algorithm in the energy-saving renovation of hospital buildings.

Passive Envelope Measures for Improving Energy Efficiency in the Energy Retrofit of Buildings in Italy

Passive Envelope Measures for Improving Energy Efficiency in the Energy Retrofit of Buildings in Italy

Examining building energy retrofit effects on indoor environmental quality before the Covid-19 era: a critical assessment

Examining building energy retrofit effects on indoor environmental quality before the Covid-19 era: a critical assessment

Evaluation of cooling energy saving and ventilation renovations in office buildings by combining bioclimatic design strategies with CFD-BEM coupled simulation

Bioclimatic design knowledge and measures, including passive techniques and natural ventilation cooling, are urgently for building renovation to mitigate global warming. The performance of indoor airflow, energy, economic, and environmental aspects has been researched separately. However, developing a comprehensive framework to investigate bioclimatic strategies under the impact of climate change is challenging. This study aims to integrate bioclimatic design strategies with a coupled simulation approach using Fluent and EnergyPlus to evaluate retrofitting techniques for a single-room office in a university building in a hot summer and cold winter climate. A bioclimatic analysis was conducted to recommend cost-effective passive cooling strategies, including natural ventilation and window shading systems. Two passive measures, changing window types and furniture layouts, were included in renovation packages. Results indicated that the empty model is not valid compared to the fully furnished model when calculating room air change per hour (ACH). Natural ventilation was the most cost-effective strategy to mitigate climate change, with a net present value (NPV) ranging from USD 135.09 to 402.81 over 30 years. However, a higher ACH did not ensure a longer natural ventilation period. By changing the top-hung window to a vertical sash and implementing a movable furniture layout, can achieve better ventilation efficiency. The installation of window vertical shadings had the highest annual emission savings by 2080, while it performed negative economic viability in both the present and the 2050 climates. This research demonstrated how combining bioclimatic measures with a co-simulation approach can offer a thorough evaluation of building energy retrofitting. The results could support architectural and engineering design by integrating bioclimate measures to identify the most effective strategies.

Challenges to energy retrofitting of existing office buildings in high-rise high-density cities: The case of Hong Kong

Achieving carbon neutrality by 2050 has become a global goal, sparking concerns regarding energy consumption and carbon emissions in building operations. Office buildings in high-rise high-density cities serve as central business districts, contributing significantly to the city’s economic activity and consuming a lot of energy. The process of retrofitting existing office buildings for energy efficiency in high-rise high-density cities tends to be challenging. However, there is a lack of comprehensive understanding of the challenges involved in office buildings’ energy retrofitting, as they have not been thoroughly explored. This study aims to investigate the challenges to the existing office building energy retrofitting (EOBER) in high-rise high-density cities with real cases in Hong Kong. Initially, a systematic literature review was undertaken to identify 49 potential EOBER challenges and categorized into seven groups: technical, financial, institutional, social, environmental, regulatory, and other categories. Afterward, 23 EOBER challenges were identified through 24 semi-structured interviews with 36 real office building energy retrofitting cases in Hong Kong. Moreover, these challenges were quantified by the Z-numbers-based Delphi survey and analysis. Results show that regulatory challenges are the primary challenges, followed by financial challenges. The lack of government incentives, policies, legislation and regulations significantly hinders practitioners’ ability to engage in energy retrofitting initiatives. The long payback period of building energy retrofitting poses a critical financial concern for practitioners embracing such initiatives. In the end, this research proposed integrated strategies to tackle these challenges and increase building energy efficiency, including launching financial and regulatory incentives, shortening the interval for mandatory energy audits, disseminating knowledge, and diversifying finance channels of building energy retrofitting. The findings contribute to the body of knowledge by employing systems thinking to identify and evaluate EOBER challenges in high-rise high-density cities through empirical methodologies. Moreover, this study provides valuable references for practitioners in navigating these challenges and minimizing risks associated with the retrofitting process.

The Challenge of Integrating Seismic and Energy Retrofitting of Buildings: An Opportunity for Sustainable Materials?

Recent earthquakes and escalating energy demands are exposing building stock deficiencies, particularly in terms of seismic resilience and energy efficiency. Many aged constructions do not fulfil current regulations both in terms of seismic and thermal design principles, thus requiring suitable retrofitting solutions. Integrated approaches for concurrent seismic and energy renovation have emerged as promising strategies in recent years, offering holistic solutions that optimize interventions and maximize benefits. While these combined methods hold significant potential for practical applications, there remain opportunities for further research to enhance their advantages. Furthermore, addressing climate concerns requires concentrated effort within the construction sector, where synergetic refurbishments can serve a dual purpose by reducing emissions and promoting the use of more sustainable materials. This study discusses strategies proposed in the literature for integrated retrofitting, considering their environmental impact, both in terms of energy performance and embodied carbon. The overview shows the innovation potential for the development of materials and systems combining acceptable performance with eco-friendly attributes. Yet, their application in integrated retrofitting systems, either as structural components or insulators, is still limited, underscoring the need for continued investigation and advancement. This paper concludes with recommendations to inspire further research and advancements in this critical field.

Investigating Energy Renovation of Multi-Owner Buildings and Real Estate Market Issues in a Degraded Greek Urban Area

States establish ambitious policies and important measures to achieve targets for the energy upgrade of buildings but although some important barriers prevent their implementation in space, they are rather overlooked by research. In this paper, it is argued that extensive multi-ownership (MO) and weak performance of the real estate market in degraded urban areas impede the mass energy retrofitting of multi-owner buildings (MOBs), which are an important part of the urban building stock A deprived area of central Athens (Greece) that serves as a case study. With a pluridisciplinary approach based on extensive field surveys, cadastral data analysis and cases of energy renovation of buildings through a public–private partnership financing scheme as well as ways to overcome the MO issue were explored, according to the provisions of the Greek legal framework. The integrated urban regeneration approach is promoted as a means to encounter the MO issue and enhance the functioning of the real estate market by the generation of surplus values that will render the energy retrofitting of buildings more attractive to investors and thus achieve the deep renovation of MOBs towards the sustainability of the urban environment. This paper ultimately advocates the integration of energy planning with spatial planning.

Assessing the Energy Performance and Retrofit Potential of the 1980–1990s’ Residential Building Stock in China’s Jiangsu Province: A Simulation-Based Study

The building operation sector in China represents 22% of the national energy consumption and 22% of the carbon emission, of which urban residential buildings accounted for 24% in 2019. Such figures for the housing sector are projected to increase sharply in the near future, while China aims to peak CO2 emissions by 2030 and reach neutrality before 2060. To reduce the impacts of the urban housing sector and address the energy use and waste generated by large-scale demolition and reconstruction, the central government started promoting the energy retrofit of urban residential buildings, raising such policies to the national strategic level. Jiangsu Province is one of the most urbanised, with a rapid growth in the energy consumption of residential buildings. The Multi-Danyuan and Single-Danyuan Apartment built in 1980–1999 are the most representative residential types in its urban areas. While still adequate functionally, they were designed and built to low energy standards and show significant potential for energy retrofit. Nonetheless, their current performance and energy-saving potential are under-researched, while more detailed and reliable data would be critical to support retrofit design and policy making. This study investigates and characterises the typical use and energy performance of the two building types. Additionally, seven measures and six retrofit scenarios were identified based on the optimal energy reductions and regulations from selected countries. The simulations indicate that, without intervention, the energy consumption of the typical urban residential buildings can reach 122 kWh/m2 under the typical high-energy user scenario. By selecting a set of effective energy-saving measures, the operational energy use for heating and cooling can be reduced by up to 52.4%. Current local standards prove cost-efficient, although less effective in reducing energy use compared to international best practices, indicating potential improvements to the contribution of building retrofit towards achieving the national carbon reduction goals.

Evaluating the Implementation of Energy Retrofits in Historic Buildings: A Demonstration of the Energy Conservation Potential and Lessons Learned for Upscaling

This study presents an in-depth analysis of 69 case studies focusing on the energy retrofit of historic buildings, uncovering challenges, best practices, and lessons learned to balance energy efficiency improvements with heritage preservation. The findings highlight several challenges encountered during renovations, such as complex heritage evaluations, restrictions on alterations, coordination issues with authorities, technical limitations, higher investment costs, and knowledge gaps. On the other hand, identifying factors promoting renovation, including demonstrating energy savings while respecting heritage, early collaboration between planners and authorities, and quantifying investments, could incentivize owners and authorities. The limitations of a still-limited sample size, occasional incomplete data, and potential sample bias call for cautious interpretation of the presented analysis. Despite these, the study provides valuable insights into successful projects, emphasizing the need for scalability, knowledge transfer from innovative policies, and targeted policy-making for successful replication. The study concludes with a call for further development of the HiBERatlas (Historic Building Energy Retrofit atlas), an extensive resource for historic building renovation, expanding its database, collaborating with agencies, and tailoring guidance for stakeholders to foster energy retrofits in heritage buildings.

Application of the Guidelines for the Integration of Photovoltaics in Historic Buildings and Landscapes to Evaluate the Best Practices of the Historic Building Energy Retrofit Atlas

The challenge of transforming historic buildings and city centers into energy-self-sufficient environments requires innovative solutions. The research project “BiPV meets History” addressed this challenge by providing comprehensive guidelines for assessing the integration of photovoltaic (PV) systems in protected historic architectural contexts. To validate these guidelines, this study conducts a thorough examination of best practices through the mentioned guidelines, developing an application tool. Recognizing the power of well-communicated best practices in overcoming obstacles to integrated photovoltaic adoption, this tool is used to assess PV integration quality with respect to the best practice contained in the HiBERatlas database. The analysis of 17 successful refurbishment cases highlighted the robustness and reliability of the proposed methodology, considering aesthetic, technical, and energy aspects. This study emphasizes the potential of the guidelines for achieving a harmonious integration of renewable energy solutions with historic architectural heritage and landscape and improving usability through the developed tool.

Influence of urban density on energy retrofit of building stock: case study of Spain

ABSTRACT Energy retrofitting of existing buildings plays a key role in the European targets of Green House Gas reduction. The addition or substitution of construction materials is needed to improve energy performance of buildings and its environmental impact must be considered. This paper proposes a model for the assessment of the environmental impact of neighborhood retrofit in relation with urban density. The model is based on the decomposition of buildings into functional elements and the quantification of construction materials used in building energy retrofitting. As a novelty, the need of road rehabilitation was also considered. The environmental impact was assessed in terms of Embodied Energy (EE) and Embodied Carbon (EC). The operational energy after retrofit was also calculated. The results bring the evidence of the relation between the urban density and the EE and EC derived from building retrofit, which can be up to 60% higher in low density areas. The sensitivity analysis carried out demonstrates the influence of the urban compactness on the environmental assessment results. The model proposed can assist in the design of retrofit plans at urban level by highlighting those retrofit measures with most significant environmental impact depending on the urban density.

Energy savings potential and life cycle costs of deep energy retrofits in buildings with and without habitable style loft attic conversions: A case study of Irelands residential sector

This paper evaluated the potential energy and life cycle cost (LCC) savings arising from the deep energy retrofit of residential buildings. The cost optimal model was determined for material upgrades and the addition of an air-to-water heat pump, where the household level of savings at 2023 energy prices will be dependent on the typical housing characteristics and weather conditions. LCC savings post retrofit for a detached dwelling insulated at the ceiling/rafter including installation of a heat pump amount to a €20,031-€21,370 for an uninsulated dwelling pre-retrofit, rising to €38,448 for dwellings with a habitable loft conversion. Partially insulated dwellings, pre-retrofit did not all incur favourable returns in investment, and in some cases were unviable. Although, the application of a 50% grant results in a viable return on investment for home owners. A sensitivity analysis found high discount rates, fuel prices and increasing capital costs can negate positive returns on investment. Finally, at a national level energy saving of 7.72 TWh by 2030 could be realised if the Irish Climate Action Plan 2023 retrofit targets are adhered to. In addition, total LCC savings could be valued at €1.4 billion. Where only material upgrade are pursued a loss occurs of €0.56 billion.

A Decision Support System for the Selection of Insulating Material in Energy Retrofit of Industrial Buildings: A New Robust Ordinal Regression Approach

The criteria for selecting insulating materials in the energy retrofitting of industrial buildings can often be conflicting, leading to a multicriteria decision-making problem. This is the first study to take an indirect elicitation approach to solving this selection problem, which is particularly applicable in the preliminary phases of negotiation with all of the decision-makers involved. We introduce a nonlinear indirect elicitation approach for PROMETHEE II that uses Bézier curves as nonlinear preference curves to fit the decision-maker's preferences, i.e., indifference and/or strict preferences for insulating materials that are taken as references. In our approach, no parameters need to be initially set, and thus, it has the advantage of setting both the preference curves on the criteria and the criteria weights when the decision-maker is not confident. The set of Bézier curves and criteria weights that best fits the preferences given by the decision-maker may thus be achieved and visualized, which provides managerial insights as it makes explicit the preference structure of the decision-maker. We use a case study to validate our proposal in a real setting and confirm that linear preference curves would have achieved less clear relations between the insulating materials used as references respect to Bèzier curves.

Key Performance Indicators: their use in the energy efficiency retrofit for historic buildings

Energy efficiency in the built environment is gaining ground due to policies to mitigate climate change impact. This contribution focuses on investigating the role of Key Performance Indicators (KPIs) that can be useful for the energy retrofit of historic buildings. The KPIs were hinged upon PESTEL domains (Political, Economic, Social, Technological, Environmental, and Legislative) in order to define objective and measurable criteria that allow for a comprehensive evaluation of an energy retrofit performance. A literature review carried out through the PRISMA flow chart allowed to select 59 papers, subsequently analyzed to investigate the occurrences of the selected KPIs. The findings showed that the political domain is the less considered, differently from the legislative one, whose KPI highlighted the importance of being compliant with regulations. The domains representing economic, social, technological, and environmental KPIs are mostly present together in the scientific literature, underlining the importance of a holistic and multidisciplinary approach. Future research should be oriented towards delineation of best practices to meet sustainability and conservation needs, and to better integrate current policies and international requirements.

A pilot project for energy retrofit of educational buildings - The engineering campus of the University of L’Aquila

The engineering campus of the University of L’Aquila represents a complex use case in the context of energy efficiency, mainly due to its size, the high thermal power, the hybrid hydronic and ventilation system, the absence of a room’s thermal control, and the progressive obsolescence of the heating plant. An in-depth recognition and study of the campus’ HVAC system made it possible to assess the main energy inefficiencies and define interventions to improve its performance. The energy retrofit, carried out by the University’s “Energy Commission Workgroup”, highlighted the main criticalities and potentials of the HVAC system providing viable paths for energy optimization. Among them, one of the hypothesized interventions concerned the thermal regulation of the heating plant, which is, to date, substantially absent. This work presents the results of a Pilot Project to quantitatively evaluate the effectiveness of the closed-loop control on a thermal system. Two classrooms in the Engineering Campus, similar in geometry, orientation, and occupancy, were selected. One of them has been equipped with a control system. The results of the monitoring campaign showed that the proposed system achieved more than 30% energy savings over a three-month trial period.

Energy retrofitting of non-residential buildings with regards to heritage value and the established cultural landscape

Interior insulation can be a problematic necessity in case of renovating poorly insulated existing buildings of heritage value. The same applies to younger buildings with interior insulation that later might be qualified as worthy of protection due to their role within an established cultural landscape. This article covers a complex of non-residential buildings, which are part of a university campus. These buildings, from the 60’s, were built as a mix of poured and prefabricated concrete structures with interior insulation. The buildings’ performance, after more than 60 years in use, was analysed based on theoretical knowledge and professional experience, available project documentation, observations, and examinations regarding the current condition of materials and components. Basing on gathered data and primary simulations of hygrothermal performance, the retrofitting potential using internal insulation as a measure of retrofit in consideration of heritage value restrictions was evaluated. Protected buildings of this construction type are, to our knowledge, so far rarely part of retrofit analyses and therefore worthy of being looked at. The building technology used is considered typical for its construction place and time, making the results representative for a larger number of comparable buildings.