Search Results (59)

Applying circular economy principles to the renovation of existing buildings is increasingly recognized as essential to achieving Europe’s climate and energy goals. However, current decision-making frameworks rarely integrate life cycle carbon assessment with multi-criteria evaluation to support circular renovation strategies. This paper introduces an innovative framework that combines life cycle carbon assessment with multi-criteria decision analysis to identify and sequence circular renovation measures. The framework was applied to a residential case study in the Netherlands, using IES VE for operational carbon assessment and One Click LCA for embodied carbon assessment, with results evaluated using PROMETHEE multi-criteria analysis. Renovation measures were assessed based on operational and embodied carbon (including Module D), energy use intensity, cost, payback period, and disruption. The evaluation also introduced the embodied-to-operational carbon ratio (EOCR), a novel metric representing the proportion of embodied carbon, including Module D, relative to operational carbon savings over the building’s lifecycle. The homeowner’s preferences regarding these criteria were considered in determining the final ranking. The findings show that circular insulation options involving reused materials and designed for disassembly achieved the lowest embodied carbon emissions and lowest EOCR scores, with reused PIR achieving a 94% reduction compared to new PIR boards. The impact of including Module D on the ranking of renovation options varies based on the end-of-life scenario. The framework demonstrates how circular renovation benefits can be made more visible to decision-makers, promoting broader adoption. Full article

Ensuring proper indoor air quality in high-rise apartment buildings is a crucial challenge, particularly when upgrading ventilation systems during deep energy renovation of existing buildings. This study evaluates the condition of existing ventilation systems and assesses the performance, cost, and energy efficiency of different mechanical ventilation solutions with heat recovery, including centralized and decentralized balanced ventilation with heat recovery, single-room ventilation units, and mechanical extract ventilation with heat pump heat recovery or without heat recovery. An onsite survey revealed significant deficiencies in existing ventilation systems, such as airtight window installations without dedicated fresh air valves, misaligned and decayed exhaust shafts, and inadequate extract airflow in kitchens and bathrooms. SWOT analyses for each system highlighted their strengths, weaknesses, opportunities, and threats, providing valuable insights for decision-makers. The results indicate that while centralized and decentralized mechanical ventilation with heat recovery enhances energy efficiency and indoor air quality in high-rise multifamily apartment buildings, challenges such as high installation costs, maintenance complexity, and architectural constraints must be addressed. Heat recovery with exhaust air heat pumps is a viable alternative for high-rise apartment buildings when more efficient options are not feasible. Full article

Most of Italy’s residential building stock predates contemporary structural safety and energy efficiency regulatory frameworks. Today, policymakers face the challenge of choosing whether to prioritise renovation or opt for demolition and reconstruction; both options carry significant socio-economic and environmental consequences and require extensive knowledge of the built heritage. However, detailed architecture-specific data remain scarce, as existing databases lack granular information. Moreover, traditional urban-level knowledge mapping approaches may be resource-intensive. To address this data gap, this study proposes a semi-automated methodology for generating graph-based digital models representing residential building floor plans. Using graph theory, floor spatial layouts are mapped into connectivity graphs and transformed into topological models. These models are enriched with functional data about spaces by assigning conditional topological rules based on node centrality metrics. The method was tested on 98 buildings in Bologna, Italy, yielding an 89.8% success rate and demonstrating its effectiveness in data-limited contexts. The resulting dataset facilitates the analysis of floor spatial configurations and the extraction of geometric attributes, laying the foundation for future analyses that will integrate machine learning techniques for functional detection and typological clustering. Full article

This paper provides a methodology for improving the modelling and design of BIPV façades through in-depth solar irradiation calculations using free and open-source software, mainly GIS, in addition to free data, such as LiDAR, cadastres and meteorological databases. The objective is to help BIPV design with a universal and easy-to-replicate procedure. The methodology is validated with the case study of Building 42 in the CIEMAT campus in Madrid, which was renovated in 2017 to integrate photovoltaic arrays in the east, south and west façades, with monitoring data of the main electrical and meteorological conditions. The main novelty is the development of a methodology where LiDAR data are combined with building vector information to create an enhanced high-definition DSM, which is used to develop precise yearly, monthly and daily façade irradiation estimations. The simulation takes into account terrain elevation and surrounding buildings and can optionally include existing vegetation. Gridded heatmap layouts for each façade area are provided at a spatial resolution of 1 metre, which can translate to PV potential. This methodology can contribute to the decision-making process for the implementation of BIPV in building façades by aiding in the selection of the areas that are more suitable for PV generation. Full article

Industrial buildings play vital roles in a society, from shaping the economic, technological, cultural, and social fabric of society to contributing to its growth, development, and resilience. Hence, often at the end of their lifespans, they are “preserved” for their historical value through renovation. Considerations for renovation often include their historical significance, structural integrity, adaptive reuse, social sustainability, financial viability, and environmental impacts. Among these considerations, the carbon emissions associated with a project are increasingly becoming a factor of relevance when a historical building is to be sensitively renovated so that it can continue to contribute to local sustainability. However, embodied carbon is often overshadowed by operational carbon and overlooked in the development of renovation options. This paper argues for the need to include embodied carbon in the consideration of any renovation process and for guidelines for doing so. The argument is built upon a systematic review of current practices in the renovation of industrial heritage buildings across selected representative countries from the Global South and the Global North, in the belief that the former could learn valuable lessons from the latter, which has more extensive experience in considering embodied carbon in such processes. The argument also shows the difference in policy between different countries and articulates how the inclusion of embodied carbon might support environmental targets in the Global South. Based on a quantitative comparison, this review explains why embodied carbon (EC) is missing in renovations of industrial heritage buildings in the Global South. This study estimates the proportion and value of EC within the total life cycle in renovations of industrial buildings to support the argument. Above all, a calculation using a standard life cycle assessment (LCA) tool (ISO14040 & 14044) applied to four successful examples and a quantitative comparison highlight the benefits of including embodied carbon in renovations of industrial buildings and the carbon savings in the Global South and further supports our argument. Full article

This review examines Ghana’s progress in sanitation. These efforts include the containment, transport, treatment, and disposal or reuse of human waste. This research specifically examined the current sanitation processes and programming efforts within Ghana, West Africa. Some reports indicate that Ghana is the second dirtiest country in Africa and the seventh dirtiest country in the world. A review of the current water, sanitation, and hygiene (WASH) options within the country indicates that significant efforts need to be undertaken. There are multiple toilet options and current practices within the country for the disposal of excrement. Unfortunately, the municipal sewer systems and wastewater treatment facilities within the country are either broken down or severely inadequate compared to their surrounding population. Current WASH programming, extension efforts, and key factors affecting the uptake of sanitation investment are reviewed. The price point where consumers would utilize sanitation products and services was analyzed, as well as the cost-to-benefit ratio of specific technologies for community members. This review demonstrated that initiatives should be undertaken to provide more sanitation professionals, renovate and expand urban municipal sewerage systems, and provide basic access to rural community areas. It was recommended that future programming, extension, and policy efforts be intentional and include relevant stakeholders and community members to provide a greater opportunity for establishing successful and substantial efforts. Full article

A common retrofitting method for wind farms is the replacement of low-power turbines with high-power ones. The determination of the optimal replacement sequence for the purpose of maximizing revenue is a significant challenge. This paper employs a combination of FLORIS and a sequencing algorithm to simulate the power output resulting from the replacement of 1.5 MW small turbines with 5 MW large turbines. This study demonstrates that the optimal strategy for maximizing the overall power output is to replace the turbines in the first column. When the turbines situated in the first column have already undergone replacement or are unable to be replaced due to the characteristics of the terrain, it would be prudent to prioritize those in the final column. In the case of staggered arrangements, priority should be given to diagonal points that do not have turbines situated behind them. In the case of replacing the same number of large wind turbines, the preferred replacement option has a minimal impact on the power output of the existing small wind turbines, with an estimated reduction of 0.67%. This effectively enhances the economic efficiency of wind farm renovation. Full article

Limited material options and economic conditions significantly restrict the potential for energy efficiency improvements in rural houses in China’s cold regions. It is worth exploring how to propose suitable energy-saving renovation plans for rural houses in cold regions under practical constraints. By using Grasshopper within Rhinoceros 8 software, an algorithm integrates material selection, energy consumption calculations, and economic analysis. The method efficiently generates thermal optimization schemes, providing insights into energy use, costs, and payback periods. In a case study of a typical rural house in Daqing City, the optimized scheme achieved over 70% energy savings compared to traditional homes, with renovation costs amounting to less than 40% of residents’ annual income and a 2-year payback period. This significant improvement highlights the potential of the proposed method in enhancing the energy efficiency and economic viability of rural house renovations. Full article

The architectural heritage of a particular place, in most cases, is characterised by vernacular and unique constructions that have been adapted to local climate conditions. For this purpose, specific materials and construction methods have traditionally been used that, in addition to the durability of the construction, also allow for the consideration of the energy efficiency of the building itself. The present intersection of climate change and architecture has led to new exposure to the external agents for which constructions were designed, forcing, in most cases, a review of building envelopes and very costly proposals. From the point of view of efficiency, intervention strategies with passive measures are proposed that not only improve the energy performance and maintenance of buildings themselves, but also lower the overall energy consumption. Using a heritage case study of the city of Seville, the Moroccan Pavilion, at Expo 92, this work includes an analysis and proposal of effective action through a methodological study of energy efficiency. The problem of high energy consumption during the summer months in Seville is tested in the Pavilion. The results indicate an urgent need for renovation, and among different options, new intervention measures are recommended as an alternative to consumption based on knowledge and tradition; moreover, passive construction elements are proposed in accordance with the climatic reality of the environment for optimal conservation in new climate scenarios. Full article

The preservation of historical traditional architectural ensembles faces multifaceted challenges, and the need for facade renovation and updates has become increasingly prominent. In conventional architectural updating and renovation processes, assessing design schemes and the redesigning component are often time-consuming and labor-intensive. The knowledge-driven method utilizes a wide range of knowledge resources, such as historical documents, architectural drawings, and photographs, commonly used to guide and optimize the conservation, restoration, and management of architectural heritage. Recently, the emergence of artificial intelligence-generated content (AIGC) technologies has provided new solutions for creating architectural facades, introducing a new research paradigm to the renovation plans for historic districts with their variety of options and high efficiency. In this study, we propose a workflow combining Grasshopper with Stable Diffusion: starting with Grasshopper to generate concise line drawings, then using the ControlNet and low-rank adaptation (LoRA) models to produce images of traditional Minnan architectural facades, allowing designers to quickly preview and modify the facade designs during the renovation of traditional architectural clusters. Our research results demonstrate Stable Diffusion’s precise understanding and execution ability concerning architectural facade elements, capable of generating regional traditional architectural facades that meet architects’ requirements for style, size, and form based on existing images and prompt descriptions, revealing the immense potential for application in the renovation of traditional architectural groups and historic districts. It should be noted that the correlation between specific architectural images and proprietary term prompts still requires further addition due to the limitations of the database. Although the model generally performs well when trained on traditional Chinese ancient buildings, the accuracy and clarity of more complex decorative parts still need enhancement, necessitating further exploration of solutions for handling facade details in the future. Full article

The development of high-rise buildings worldwide has given rise to significant concerns regarding their excessive electricity consumption. Among the various categories of high-rise structures, hotels used for business and conferences stand out as particularly extravagant in their energy use. The consequence arising from excessive energy usage is an escalation in carbon emissions, which is a primary driver of global warming. Therefore, this study aims to investigate the energy use intensity (EUI) of a hotel building located in Jakarta, Indonesia. In order to improve energy performance, this study explored various options for renovating the building envelope, such as incorporating insulation and a roof covering, as well as implementing building-integrated photovoltaics (BIPV). The building envelope renovations demonstrated a notable reduction in energy use by 15.8–27.7% per year. BIPV, such as curtain walls and double-skin façades, generated an energy use reduction of 4.8–8.6% per year. Remarkably, by combining the two approaches (i.e., adding insulation and a roof covering in the building envelope and adopting BIPV as double-skin façades), the potential reduction in energy use reached up to 32.2% per year. The findings can assist decision-makers in developing building renovation strategies for high-rise buildings while considering energy conservation. Full article

Energy and economic assessments are of great relevance in the context of decision processes for the most optimal solutions for building renovations. Following the method recommended by UNIDO, economic analyses of thermal modernization options are carried out based on the Simple Payback Time (SPBT), Net Present Value Ratio (NPVR) and Internal Rate of Return (IRR) indices. Incorporating these indicators and a new approach that involves aggregating thermomodernization activities not only in the cold and warm seasons separately, but throughout the whole year, an economic evaluation of the thermomodernization of a production space was carried out. In this case study, the renovation options included wall insulation, window replacement, the installation of infrared heater, a two-flow air diffuser (TFAD) and variable air volume. The economic effect indicated by the highest NPVR over a normative period of 15 years was obtained for the installation of an infrared heater and a TFAD with a variable mode ventilation system. The SPBT for this case was also the lowest. Full article

According to the European Energy Efficiency Directive for Buildings, member states are required to develop long-term strategies to adopt more sustainable, secure, and decarbonized energy systems in buildings by 2050. In this line of approach, an optional common regime has been established to define and calculate the smart readiness of buildings and assess their ability to adapt their operation to the needs of the occupants and the network. Thus, the smart readiness indicator (SRI) emerged, which assesses technological readiness by examining the presence and evaluation of the functionality level of various smart services, aiming at energy savings, the ability of the building to respond to users’ needs, and energy flexibility. This paper focuses on examining the SRI calculation methodology’s application to an office building, which is currently being deeply renovated. Initially, there is an analysis of the SRI, its calculation methodology, and its goals. This is followed by the practical calculation part of the SRI for a typical office building located in Greece and belonging to the climate zone of southern Europe. The results indicate that the SRIs application is not a straightforward issue since parameters that need to be considered are not regulated to the same degree. On the other hand, SRI can provide a stimulus for exploiting the renovation potential of buildings, precisely by integrating the various aspects and linking those to the use of innovative technologies. Full article

To achieve climate and energy goals in the building sector, the current pace of renovating existing structures must double, overcoming prevailing barriers. Key Performance Indicators play a pivotal role in science-based decision making, emphasizing both direct and indirect benefits of building retrofits. The authors aim to contribute to proper metric identification for multi-perspective building performance assessment and formulate a methodology supporting energy planning decisions. They introduce the Global Cost per Emission Savings (GCES), an aggregated indicator encompassing both public (CO₂ emissions) and private (global cost) perspectives of diverse retrofit technologies for building HVAC systems. Applied to the Italian residential building stock via the Reference Building approach, the methodology is tested using condensing gas boilers, biomass boilers, and electric heat pumps, revealing diverse environmental and economic performances. Addressing the establishment of effective decision-support tools for policymakers, the paper explores the potential impact of various policies on the favorability of technologies. Different policy scenarios are delineated to analyze how distinct approaches may influence the attractiveness of technologies. Notably, in the baseline scenario, biomass boilers hold an advantage over heat pumps according to the GCES index. However, scenarios involving technology-specific incentives or a greenhouse gases emission tax failed to alter the technological ranking, leaving heat pumps financially uncompetitive. In contrast, the TXPM scenario positions heat pumps as the most financially appealing option, penalizing biomass boilers for high particulate matter emissions. Full article

China is committed to reaching peak carbon by 2030 and carbon neutrality by 2060. The goals of reducing energy consumption and building a “beautiful China” are being urgently pursued in China. The building studied in this paper is located in the city of Turpan, where the problem of excessive energy use among buildings is significant due to the region’s hot summers and cold winters. Additionally, the fact that the office building studied in this paper has an east–west orientation is significant: the building’s main façade is oriented to the west, comprising a large area of single-layer glass curtain wall. Based on this, this paper proposes optimization strategies from two perspectives of renovation and new construction. Four design options are proposed at the retrofit level: glazed circular curtain wall; glazed enclosed curtain wall; west-facing double-glazed curtain wall circulation combined with south-facing light from the east; recycling of windows on the inside of the exterior glass curtain wall. These suggestions focus on retrofitting the glass curtain wall on the west elevation of the building. Two design options are proposed at the new-build level: west-facing south-oriented light and west-facing north-oriented light. These suggestions were primarily built around the idea of changing the orientation of the windows on the west elevation. The results show that the optimal solution is to implement the west-facing double-glazed curtain wall circulation combined with south-facing light from the east. This program shows a 64.14% reduction in heating energy consumption, a 77.12% reduction in cooling energy consumption, and a 69.67% reduction in total energy consumption. The above research has improved the deficiencies in the performance-based energy efficiency retrofit of office buildings in the region and provided new ideas and suggestions for policymakers and designers to build energy-efficiency retrofits in the early stages. Full article