Renovation Strategies Research Articles

Energy-Saving Potential of Building-Integrated Photovoltaic Technology Applied to a Library in Changsha, China

With the increasing number of public buildings worldwide, their energy consumption has garnered significant attention. This study aims to promote building energy efficiency and emission reduction by exploring the application of Building-Integrated Photovoltaic technology in library retrofitting. Using a library in Changsha City as a case study, we conducted an energy consumption analysis of the building’s envelope and identified the window section as the highest energy consumer. We proposed a novel improvement scheme—the sun-shading photovoltaic panel (which shades the sun while generating electricity). Additionally, we utilized the roof space for the installation of conventional photovoltaic panels. Simultaneously, the primary objective of this paper was to derive a renovation strategy for public buildings in regions characterized by high summer temperatures and low winter temperatures based on the renovation case of this library. This paper comprehensively investigates the length and angle of sun-shading photovoltaic panels facing different directions, as well as the azimuth angle, tilt angle, and installation spacing of the conventional photovoltaic panels on the roof. Two retrofitting schemes were proposed. Through simulation and comparison, the second scheme was found to reduce the annual electricity consumption by 1,233,354 kWh, achieving a 35.4% decrease compared to the original building. Using the Changsha library as a template for public buildings, this study provided a retrofitting approach with Building-Integrated Photovoltaic technology via DesignBuilder, which could be extended to other geographic locations. The results demonstrated the significant energy-saving effects of the proposed retrofitting scheme.

Multi-Domain Environmental Quality of Indoor Mixed-Use Open Spaces and Insights into Healthy Living—A Quarantine Hotel Case Study

In the post-pandemic context, data-driven design interventions that can endow architectural spaces with mixed-use and open characteristics that are adaptable and environmentally resilient are increasingly important. Ubiquitous semi-public architecture, such as hotel buildings, plays a crucial role in public health emergencies. Many hotels adopt mixed-use and open room spatial layouts, integrating diverse daily functions into a single tiny space, fostering flexible utilization and micro-scale space sharing; however, these also introduce potential health risks. This study offers a comprehensive evaluation of the indoor environmental quality (IEQ) of a hotel room space and discusses feasible intervention strategies for healthier renovation and rehabilitation. Taking a hotel in Shenzhen as a case, a multi-domain environmental assessment was conducted during the COVID-19 quarantine period in the summer of 2022. The study examines the health risks inherent in the hotel’s guest room and the varying patterns of IEQ factors across the hotel’s domains, including volatile organic compound concentrations, physical environmental parameters, and heat stress indices. The results illustrate diverse change trends in the chemical, physical, and heat stress factors present in the tested quarantined hotel room space throughout a typical summer day. Although most of the examined environmental factors meet local and global standards, some problems draw attention. In particular, the PM2.5 concentration was generally observed to be above the World Health Organization (WHO) air quality guideline (AQG) standards, and the interior lighting did not meet required standards most of the time. Moreover, correlation and multiple regression analyses uncover significant influence by physical environmental conditions on the concentrations of chemical pollutants in the hotel room. The study preliminarily identifies that higher relative humidity could lead to a lower concentration of CO2 while a higher PM2.5 concentration. Wet bulb globe temperature (WBGT) was observed to positively affect CO2 concentration. Further, the results suggest that even with relatively rigorous initial adjustment and re-renovation, multi-domain environmental quality in air-conditioned quarantine hotel rooms should be monitored and ameliorated from time to time. Overall, this study offers a scientific foundation for healthier upgrades of existing hotel buildings as well as provides insights into achieving environmental resilience in newly constructed hotel buildings for the post-pandemic era.

Urban Renovation from Precarious to Sustainable Districts: Study Case of Mvog-Ada in Yaounde

This article explores the possibility of transforming precarious neighbourhoods, commonly known as slums, into good-living and environmentally- friendly places by rethinking their layout. It examines the state of the study case and highlights the relationships between the road system, parcels of land and other components of the urban fabric, with the aim of resolving the problems caused by the poor occupation of urban space and the lack of architectural knowledges and basic infrastructure necessary for people's lives in Cameroon. This research addresses the problems of anarchic urbanisation, urban densification and unhealthy living conditions, it proposes concrete solutions for decongesting the area, strategically redeveloping the space and ensuring the sustainable development of the site, while incorporating a biomimetic and circular approach. To achieve this goal, it was important to put in place a renovation strategy that is both up-to-date and adapted to the local context. With this in mind, this work presents a comprehensive and innovative master plan designed to solve the problems of development, bad urban traffic and degradation of the area through the use of an appropriate methodology of sustainable urban planning. Finally, the concept of sustainable district is presented as a pillar of the development of precarious districts and as an opportunity of growth for the development of their country.

Renovation Strategies for Energy Conservation in Multi-Story Residential Buildings in Turkey

Renovation Strategies for Energy Conservation in Multi-Story Residential Buildings in Turkey

Global Warming Potential as Key Performance Indicator to steer renovation strategies for the built environment

Abstract The 2050 climate neutrality target has to deal with the challenge of upgrading the existing, highly energy-intensive building stock into a highly efficient one. Long-term renovation strategies aimed not only at optimizing operational energy, but also at reducing embodied energy and carbon are needed to facilitate the transition to a low CO2 emission. All measures adopted by the EU go in this direction and promote the use of indicators such as the Global Warming Potential (GWP) to quantify emissions from the operational phase and those embodied in building materials from cradle to grave. Material choice will play a key role. This paper analyzes the use of GWP as a Key Performance Indicator (KPI) to evaluate sustainability of building envelope renovations in relation to the materials used. In particular, GWP was used to compare the emissions associated with different solutions for insulating an existing wall to meet ZEB standards. The comparison was made between traditional thermal insulating materials and those made from recycled material, to highlight the benefits of circular design strategies that aim to reuse materials for the reduction of primary raw materials and waste. The GWP approach can be a useful decision support tool for designers, stakeholders and policy makers.

Comprehensive Enhancement and Renovation Strategies for Old Hospitals in Urban Central Areas: A Case Study of Huiai Hospital in Guangzhou

The renovation project of Huiai Hospital in Guangzhou serves as a typical example of comprehensive updating, overall planning, and phased construction for old urban hospitals. It addresses representative and complex issues encountered in the renovation of outdated hospitals. By analyzing cases of renovation in urban center old hospitals, this study identifies the constraints faced in hospital renovation, summarizes the complex issues in the construction of old hospitals, and proposes targeted renovation strategies. These strategies include vertical and horizontal development, establishing transportation interfaces, reorganizing planning structures, integrating regional characteristics, and coexisting of old and new elements. These insights provide a reference for future related hospital construction projects

Advancing Sustainability in a Residential Building in Europe: A Case Study on LCA and LCC across Different Scenarios

This study evaluates the environmental and economic performance of the "ESTIA of Athens" residential building considering its energy consumption and greenhouse gas (GHG) emissions. It also explores the potential for improvements in these areas. The European Union's strategy to reduce GHG emissions from buildings by 55% compared to 1990 levels by 2030, as part of its broader aim for climate neutrality by 2050 is a background for the study. The methodology involves a Life Cycle Assessment (LCA) using SimaPro software, monitoring energy consumption, temperature and humidity of the building. The thirteen impact categories and damage impact assessment that include human health, ecosystem and resources were examined. The study compares various scenarios, including historical data from 2018 to 2022 and two hypothetical scenarios to assess environmental impacts across different categories. Additionally, Life Cycle Costings (LCC) are performed to evaluate the economic aspects of the building's performance. The results highlight substantial differences in energy consumption, GHG emissions and economic costs among the scenarios. The findings suggest that a hypothetical scenario, referred to as Case 3, demonstrates lower environmental impacts and economic costs compared to other scenarios, indicating its potential as an optimal renovation strategy for the building. This includes reductions of 32%, 40% and 58% in the human health, ecosystems, and resources categories, respectively. A similar trend is observed across the impact categories, with reductions ranging from 4% in the Mineral Resource category to 47% in the Global Warming category. The study underscores the importance of holistic assessments in informing energy policy and renovation strategies for achieving both environmental sustainability and economic viability in buildings.

Comparative assessment of simple and detailed energy performance models for urban energy modelling based on digital twin and statistical typology database for the renovation of existing building stock

The renovation wave calls for an integrated, participatory, and neighbourhood to neighbourhood approach tailored to the local environments. This can be hindered by the lack of geometric and performance input data about the existing building stock. A parametric digital urban building energy modelling (UBEM) tool was developed for local municipalities to automate calculations for comprehensive renovation strategies utilizing public databases specifically at the neighbourhood level. This article compares the accuracy of two energy performance calculation models (seasonal heat balance method and hourly resistance–capacitance method) used within the tool to detailed energy simulation software and measured energy consumption data of existing group of residential buildings in a same neighbourhood. The accuracy for estimating the total primary energy demand was roughly below 10 % for both simplified models. The seasonal calculation method showed consistent overestimation of space heating, depending on building characteristics. Solar and internal heat gains significantly affect the accuracy of simplified heat balance calculations, particularly in well-insulated buildings, while the more detailed 5R1C lumped capacitance hourly method provides improved accuracy for space heating demand. The comparison of uniform (proportional) and project based window area distribution used in the calculation models showed only marginal difference. The study validated simple seasonal and 5R1C hourly calculation methods using data from an apartment building neighbourhood with 22 apartment buildings. Despite larger deviations in the case of individual buildings, the average deviation from measured heating demand was only around 3 %, the seasonal method slightly overestimating and the 5R1C hourly method slightly underestimating the measured values. The primary energy demand including typical values of domestic hot water and household electricity was overestimated by both simplified methods due to lower electricity and water consumption in reality although the difference was below 7 % for the entire district. This concludes that pooling the building envelope heat loss calculation on a district level improves accuracy on average allowing better assessment of comparative renovation strategies.

An innovative approach to automate BIM data retrieval and processing for building acoustic comfort calculations based on the IFC standard

Nowadays, there is a growing demand for deep renovation projects aimed at improving the energy efficiency of buildings while enhancing indoor comfort conditions for the inhabitants, both thermal and acoustic. To design effective renovation strategies, technicians need to know the current state of the building to propose acoustic or only thermal improvements. However, evaluating indoor acoustic comfort requires time-consuming and tedious calculations, which can be prone to errors when handled manually. While Building Information Modelling (BIM) can facilitate this process by leveraging the extensive contained data and offering the potential to automate these processes, such automation is not yet widespread. Typically, only geometric data is retrieved automatically from BIM models in acoustic software, while acoustic parameters must be provided manually. This paper addresses these challenges by introducing a novel approach that integrates automated data extraction from BIM with acoustic simulation tools. Specifically, an Extract, Transform and Load (ETL) solution was designed to automatically retrieve both geometric and acoustic data for an Acoustic Comfort tool, which calculates an estimation of indoor acoustic comfort, from an Industry Foundation Classes (IFC). This approach was tested in a demonstration case located in Spain, showing a significant reduction in processing time and increased accuracy compared to traditional methods of manually extracting data from BIM for acoustic assessment. This research represents a significant advance in acoustic simulations by integrating IFC data with automated processing, improving accuracy and offering practical advantages for developing more efficient and reliable BIM-based applications, thus supporting the design of deep renovation projects.

Energy Efficiency in Seasonal Homes: A Study on the Occupancy, Energy Use, and Renovation of Second Homes in Sweden

The escalating utilisation of second homes has led to an extension in heating periods and, to a certain degree, renovations to elevate the standard, resulting in augmented energy and resource consumption. A comprehensive survey was conducted in Sweden, examining user patterns across different seasons, heating systems, and implemented energy efficiency measures. The results indicate that second homes are occupied for extended periods during the summer season and intermittently throughout the year. Over half of the second homes are heated even when unoccupied, with 12% maintaining a temperature above 16 °C. The predominant heating method is direct electricity (32.2%), followed by heat pumps (29.5%) and stoves (17.5%). A variety of renovations are undertaken, primarily to enhance the standard and technical performance, but also to implement energy efficiency measures such as window replacement, additional insulation, or heat pump installation. Based on the reported user and heating patterns, and the energy renovations carried out, the potential energy savings with different energy renovation strategies were estimated for the Swedish second home stock. The results show that though lowering the temperature when a second home is unoccupied emerges as the most efficient measure, both in terms of cost-effectiveness and climate impact, it needs to be complemented with intermittent heating or dehumidification to ensure that the relative humidity is below critical levels, to avoid the risk of damages caused by, for example, mould growth. Installing a heat pump is the second most energy- and cost-effective measure and has the advantage that the indoor temperature can be maintained at rather high levels.

Actions to improve energy efficiency on the example of selected historic buildings in Poland in the context of European Union guidelines

The article presents, in the context of the guidelines of the "Long-Term Strategy for Renovation of Buildings" valid until 2050, examples of renovations of historic buildings carried out in Poland in 2018-2021, which serve as public facilities. They were designed and constructed in a manner consistent with the guidelines for the transformation of a climate-neutral economy, which stem from Article 2a of Directive 2010/31/EU of the European Parliament and of the Council of May 19, 2010. The purpose of the article is a comparative analysis of selected Polish examples of revaluation of public buildings from the point of view of the Architecture of these objects. These are: the Wagner Villa in Kostrzyn on Oder, the railway station in Białystok, the Teodor Sixt Villa in Bielsko-Biała, the office building of the Forestry Commission in Elbląg, the building of the Savings Bank in Ropczyce and the former granary in Żukowo. Also cited are the current financial tools available and the basic measures needed to ensure high energy efficiency and low-carbon performance of public buildings in the run up to 2050.

Designing with building-integrated photovoltaics (BIPV): A pathway to decarbonize residential buildings

The ambitious targets set for greenhouse gas emissions and energy efficiency by 2050 demand a critical increase of building renovation rates. This challenge is shared by most Western nations, including Europe and Switzerland, where the current annual renovation rate stands at a mere 0.6 %. In this context, designing renovation strategies using building integrated photovoltaic (BIPV) components as a new building material is one of the most promising ways to achieve decarbonization of the building stock in an economical and environmentally efficient manner. To this end, building design teams are key, especially in promoting BIPV-based projects to their clients and taking this approach into account from the initial design phase where pivotal decisions with significant impact are made. This article illustrates the potential impact of specific choices in renovation processes on the overall building performance, considering a Life-Cycle Analysis/Cost (LCA/LCC) and multi-criteria analysis. It uses a 1970's residential building as case study, examining different refurbishment scenarios. Findings reveal that scenarios integrating BIPV can significantly enhance energy savings, achieving up to 122 % in energy efficiency gains, and can meet the 2050 targets for cumulative energy demand (CED) and global warming potential (GWP). Additionally, the most effective BIPV scenarios demonstrate economic viability with a payback period of 14–18 years and internal rates of return (IRR) between 5.3 % and 5.9 %. These results underscore the economic and environmental benefits of BIPV in building renovations and advocate for its broader adoption to achieve national and international climate goals.

Built-In Environmental Construction Mechanism and Sustainable Renewal Strategies of Traditional Qiang Dwellings in Western China

Indoor air quality (IAQ) has a significant impact on human health, as people spend 90% of their time in various indoor environments. Therefore, research on IAQ is extremely necessary. However, current research on traditional Qiang residences in western Sichuan mainly focuses on the indoor thermal environment and heritage protection, with relatively little attention paid to IAQ. This study investigates the IAQ of traditional Qiang residences in western Sichuan, which have open fire pits as the core of daily life, exploring the impact of passive renovation strategies on the indoor air quality. Using simulation methods, this study employs passive strategies, such as increasing the size of windward windows, changing ventilation methods, relocating the fire pit, and enlarging interior partition openings, to improve and optimize the IAQ through natural ventilation. The results show that when the windward window sizes are 0.8 m × 1.9 m and 0.7 m × 1.55 m, the reduction in the indoor CO2 concentration is the greatest, with a maximum decrease of 0.024% at the 1.5 m plane. This paper proposes passive renovation strategies to improve the indoor air quality of Qiang residences in western Sichuan. These strategies effectively enhance the indoor air quality of Qiang residences and address the research gap on indoor air quality in regional Qiang residences in western Sichuan. The insights and methods presented contribute to the improvement of the indoor air quality in traditional buildings and support the sustainable development of traditional architecture.

New Acoustic Design for the Piscina Mirabilis Located nearby the Port of Misenum

Many heritage buildings from ancient Rome are being refurbished based on their original plan’s structure. One of them is the piscina mirabilis located nearby in Naples, which was a cistern used by the Romans to collect drinkable water for the navy waiting in the port of Misenum. The piscina mirabilis has similar architectural characteristics to a “cathedral”; however, its current precarious architectural state is the result of high levels of humidity that have caused the proliferation of mold on its vertical and horizontal surfaces over the centuries. Acoustic measurements were conducted inside the piscina mirabilis, highlighting an existing condition of the room being very reverberant, not suitable for occasional speech and conversations. The design proposed by the authors involves some mitigation solutions for the acoustics, mainly focused on controlling the low–medium frequencies and the realization of a restoration project consisting of a raised timber-floored walkway that runs along the perimeter walls, with the addition of water covering the existing floor as a natural element dominating the room volume, which represents the primary function of the building in antiquity. A waterfall was designed to be on the northern side wall. Acoustic studies were an important part of the refurbishment strategy, and a mitigation solution was devised to control medium–low frequencies by using inflated balloons of different sizes that were suspended from the ceiling vaults instead of widely used acoustic panels. The proposed strategy lowered the reverberation time by 3–4 s to accommodate a minimal level of conversational understanding. Such a solution is appropriate for this heritage building as well as other future conservation projects.

Construction of Urban Spatial Intelligent Planning and Design System Under the Background of Big Data

Based on the induction of potentially utilisable micro-spaces in typical old residential communities, this study selects the communities located at 19 and 22 Yuhe Street, Taiyuan City, Shanxi Province, as typical research objects. By employing space syntax analysis, the spatial properties of these micro-spaces are examined and matched with the activity needs of various age groups within the community. By leveraging the characteristics of activity periods for all age groups, the study also proposes a composite design for less disruptive activity spaces. Consequently, optimisation suggestions for the renovation of public spaces in these two communities are presented, aiming to specifically meet the activity needs of residents of all ages within the limited space of the community. This research provides an analytical framework and methodological approach for the renovation strategies of old residential communities.

Optimizing decarbonation and sustainability of concrete pavement: A case study

This study focuses on the actual project of rural road ‘concrete to asphalt’ pavement renovation, deeply integrating the design concept of full structure regeneration and the innovation of in-situ regeneration technology for old cement pavement. Through the life cycle assessment method, an environmental impact quantification assessment model is used. Based on the analysis of the environmental benefits of traditional pavement renovation technology (using multi-hammer crushed stone and hot mix asphalt production technology), the environmental advantages of the full-structure regeneration technology scheme are outlined, including the recycling of recycled asphalt pavement materials, application of emulsified asphalt plant mixing cold regeneration technology, and implementation of resonance crushed stone on-site regeneration technology. At the same time, sensitivity analysis methods are used to deeply analyze the sensitivity of changes in parameters such as surface and base thickness, transportation distance, and environmental factors to the overall environmental impact. The research results indicate that the optimization plan can achieve a 57.97 % reduction in total energy consumption and a 71.45 % reduction in total carbon emissions. Additionally, the recycling and utilization of RAP materials significantly reduce the demand for new mineral materials and asphalt. For a 1-kilometer road surface, mineral materials save up to 82.39 % and asphalt saves up to 27.11 %. The energy consumption and carbon emissions generated during the raw material production stage in both schemes contribute the most to the environmental impact of road construction. The analysis found that the environmental benefits of the optimization plan mainly come from the recycling of the old cement concrete pavement as the base layer after resonance crushing, as well as the use of emulsified asphalt mixture cold recycling instead of the lower layer of hot mix asphalt concrete, achieving full-scale recycling of the pavement renovation. The relevant findings provide a data foundation or the improvement and upgrading of energy-saving and emission reduction technologies in road surface renovation and offer valuable insights for future research on sustainable road surface renovation strategies.

Generating meteorological files of future climates with heatwaves in urban context to evaluate building overheating: An energy-efficient dwelling case study

Because of climate change, present-day buildings will be subject to more extreme conditions by the end of the century. Indoor overheating will increase in summer, resulting in severe thermal discomfort or significant cooling needs to avoid heat stress. Existing buildings therefore need to be adapted. However, current renovation strategies are generally aimed at reducing heating energy consumption. This study presents a methodology for assessing the impact of climate change during summer and heatwave periods on indoor overheating of an existing building within an urban context. The proposed methodology is applied to the case study of a French urban dwelling within an energy-efficient renovated building. The thermo-aeraulic dwelling model built on TRNSYS and CONTAM, as well as the urban heat island model implemented on UWG, are calibrated and validated thanks to a field measurement campaign of a multi-family building in Lyon during the summer of 2022. Results show that thermal discomfort will rise sharply by the end of the century, and could reach extreme levels in the worst emission scenario. Use of windows and solar protections allows to reduce the percentage of time over 28 °C from 40 % to 54 % depending on the future scenario. Ventilation by opening windows, which is the most commonly used cooling passive strategies, continue to be essential to reduce indoor overheating in high insulated building under future climates. However, its efficiency is very dependent of occupant behaviour.

Optimization of green infrastructures for sustaining urban stormwater quality and quantity: An integrated resilience evaluation

Coupling natural green infrastructure with artificial gray infrastructure is considered a key solution for mitigating the risk of waterlogging and water quality problems caused by rapid urbanization. However, further research is needed to evaluate and optimize the utility of gray–green system considering multiple key factors. Here, the effects of gray–green system on both the water quality and quantity were investigated based on the Storm Water Management Model-InfoWorks ICM (SWMM-ICM) and bivariate copula functions. A resilience index that integrates reliability, bearing capacity, recovery speed, and recovery capacity was then proposed. Taking a typical catchment area in Beijing as an example, the results showed that the resilience index proposed is effective for evaluating the stormwater management of gray–green system. The integration of gray–green infrastructures improved the resilience of urban stormwater management, particularly in terms of controlling the water quality (improved by 1.0–4.0 %) rather than the water quantity (only 0.04–0.3 %). Direct confluence and average distribution strategies of gray–green system were more effective for water quality management, as resilience ranged from 0.7478 to 0.7605. To mitigate the ever-increasing water risks under climate change, the direct confluence, and average or downstream renovation strategies are hot spots for system renovation in the future. These results contribute to a better understanding of gray–green system and provide the foundation for sustainable water quality and quantity management in global cities.

Toward sustainable urban energy solutions: Introducing F NeCESSCity framework for energy-saving smart city configuration

This research aims to develop a Framework Necessary for the Configuration of Energy-Saving Smart Cities (F NeCESSCity) that incorporates the essential considerations for establishing an energy-saving smart city (ESSC). F NeCESSCity encompasses: (i) a Scan-to-BIM method for the digital virtualization of existing cities, and (ii) a methodology for deriving an optimal renovation strategy at the ESSC level, considering energy performance and economic factors. The application of F NeCESSCity to real-world scenarios has demonstrated that (i) fast and reliable modeling is achievable, (ii) a broad spectrum of alternatives can be developed and assessed, and (iii) an optimal renovation strategy at the ESSC level can be identified. The use of F NeCESSCity is expected to facilitate the successful development of ESSC plans, where virtual modeling and the evaluation of renovation alternatives are realized.

Numerical Analysis of Roof Wind Pressure Distribution in Renovated Historical Buildings: Preventive Protection Measures to Mitigate Typhoon Damage

Strong winds or typhoon disasters pose significant risks to historical buildings in many countries and regions. Although numerous researchers have discussed the damage caused by natural wind disasters, little attention has been paid to the potential impact of renovation and adaptive reuse strategies on the wind resistance performance of historical buildings—an avoidable human-induced factor. This study selected the representative ancestral hall building in Guangzhou, namely Lujiang Academy, for on-site investigation and Computational Fluid Dynamics (CFD) simulation analysis. It examined two renovation approaches: installing glass curtain walls around the courtyard and enclosing the top of the courtyard with a glass canopy. This study also assessed the roof wind pressure distribution in its unaltered state to evaluate the impact of different renovation strategies on roof wind load distribution. The results showed that installing glass curtain walls can effectively reduce the upward suction effect on the main hall roof, thereby improving its wind resistance performance. Conversely, enclosing the courtyard with a glass canopy may increase negative pressure on areas such as the eaves and corridor roofs, raising the risk of roof damage. This study systematically evaluated the renovation strategies for historical buildings, detailing the specific impacts of different retrofit measures on the wind resistance performance of building roofs. The methods and findings are significant not only for the renovation of ancestral hall heritage buildings in Guangzhou but also for providing practical scientific methods and technical strategies for the conservation and renovation of similar historical structures. This research demonstrates an effective approach to enhancing wind resistance and preventive protection for historical buildings.