Search Results (209)

Urban areas are responsible for most of Europe’s energy demand and emissions and urgently require building retrofits to meet climate neutrality goals. This study evaluates the energy efficiency potential of three public school buildings in western Macedonia, Greece—a cold-climate region with high heating needs. The buildings, constructed between 1986 and 2003, exhibited poor insulation, outdated electromechanical systems, and inefficient lighting, resulting in high oil consumption and low energy ratings. A robust methodology is applied, combining detailed on-site energy audits, thermophysical diagnostics based on U-value calculations, and a techno-economic assessment utilizing Net Present Value (NPV), Internal Rate of Return (IRR), and SWOT analysis. The study evaluates a series of retrofit measures, including ceiling insulation, high-efficiency lighting replacements, and boiler modernization, against both technical performance criteria and financial viability. Results indicate that ceiling insulation and lighting system upgrades yield positive economic returns, while wall and floor insulation measures remain financially unattractive without external subsidies. The findings are further validated through sensitivity analysis and policy scenario modeling, revealing how targeted investments, especially when supported by public funding schemes, can maximize energy savings and emissions reductions. The study concludes that selective implementation of cost-effective measures, supported by public grants, can achieve energy targets, improve indoor environments, and serve as a replicable model of targeted retrofits across the region, though reliance on external funding and high upfront costs pose challenges. Full article

Global climate change has intensified the challenges of low-temperature, low-light, and high-humidity microclimates in North China’s greenhouses during winter, exposing the limitations of traditional controlled-environment agriculture (CEA) facilities. This study monitored air temperature, relative humidity, and light intensity in three greenhouse types—an externally insulated plastic greenhouse, soft-shell solar greenhouse, and brick-walled solar greenhouse—across three overwintering periods (pre-, mid-, post-) using high-precision sensors (monitoring period is from 1 October 2024 to 31 March 2025). A Comprehensive Evaluation Index (CEI) based on the entropy method was developed, integrating seven indicators (daily average temperature, temperature range, hours below 5 °C, average humidity, hours above 80% humidity, average light intensity, and light utilization efficiency) to systematically evaluate greenhouse microclimate regulation performance. Results showed that the brick-walled solar greenhouse exhibited superior thermal insulation, with nearly zero hours below 5 °C during mid-overwintering, while the soft-shell solar greenhouse achieved the highest light utilization efficiency (75.1–79.6%). The externally insulated plastic greenhouse exhibited the highest relative humidity (>80% for 13–19 h/day) but a poor thermal insulation performance. The CEI ranked the brick-walled solar greenhouse (0.86) and the soft-shell solar greenhouse (0.84) significantly higher than the externally insulated plastic greenhouse (0.39), with the relative humidity significantly negatively correlated with light indicators (P < 0.05), and the temperature and light indicators strongly correlated with the CEI (P < 0.01). Structural design and material innovation are critical for climate adaptation. Brick-walled and soft-shell solar greenhouses balance thermal and light performance, while the externally insulated plastic greenhouse faces structural limitations. The findings provide a scientific basis for greenhouse optimization and regional layout planning. Full article

Lecture halls are characterized by large spatial dimensions, deep floor plans, and high occupant densities. Lectures are typically conducted using multimedia and blackboard-based teaching, placing higher demands on the indoor light and thermal environment compared to standard classrooms. This study aims to simulate the interrelationships between multiple building envelope parameters and building performance, in order to improve visual and thermal comfort while reducing energy consumption in cold-region lecture halls. Based on seven key envelope parameters—including openable window area ratio, west-facing window-to-wall ratio, exterior insulation thickness, shading element spacing, angle and width, and window glass type—a multi-objective optimization framework was established. The optimization process targeted three key performance indicators—useful daylight illuminance (UDI), energy use intensity (EUI), and thermal comfort percentage (TCP)—in the context of a stepped classroom. The results show that increasing the thickness of exterior insulation and reducing the width of shading components contribute positively to photothermal comfort without compromising thermal and visual performance. Compared with the baseline design, optimized schemes that incorporate appropriate west-facing window-to-wall ratios, openable window areas, insulation thicknesses, and external shading designs can reduce annual energy consumption by up to 10.82%, and increase UDI and TCP by 12.79% and 36.41%, respectively. These improvements are also found to be economically viable. Full article

In response to the growing demand for sustainable and performance-driven building design, this study proposes an integrated digital methodology that combines Building Information Modeling (BIM), parametric scripting, and multi-criteria decision-making (MCDM) to optimize external wall assemblies. The approach leverages Autodesk Revit and Dynamo to automate the parametrization of insulation thickness while ensuring compliance with regulatory thresholds for thermal transmittance and surface mass. Acoustic performance is estimated using ECHO software, and a Weighted Sum Model (WSM) is applied to evaluate and rank configurations based on four criteria: economic cost, Global Warming Potential (GWP), embodied energy, and acoustic insulation. A case study involving 24 wall assemblies—generated from eight base stratigraphies and three insulation materials—demonstrates the method’s ability to balance environmental impact, occupant comfort, and construction feasibility. The results indicate that natural and bio-based materials, such as rammed earth and cork, offer the best overall performance, while conventional systems remain competitive in terms of cost. The proposed workflow reduces design time, increases transparency, and supports informed decision-making during early design stages. This research contributes to the digitalization of sustainability assessment in architecture by promoting integrative, replicable, and regulation-aligned practices for low-impact building envelopes. Full article

The aim of this study is to systematically investigate the influence of hydrophobic aerogel on the performance of aerogel cement-based expanded polystyrene (EPS) insulation board (ACEPS board) under freeze–thaw cycles (FTCs) and to predict its service life in four typical climate zones: Beijing, Harbin, Urumqi, and Nanjing. The effects of aerogel content on compressive strength, volumetric water absorption, thermal conductivity, and pore structure evolution of ACEPS were thoroughly analyzed through FTC testing. The results demonstrated that aerogel significantly reduced the volumetric water absorption of ACEPS due to its excellent hydrophobicity, thereby decreasing the compressive strength attenuation from 40% to 24%, suppressing the increase in thermal conductivity from 0.0130 to 0.0055 W/(m·K), and mitigating pore structure degradation. In the regional service life prediction, aerogel-modified ACEPS exhibited significantly improved freeze–thaw resistance in the cold climates of Harbin and Urumqi, as well as in the high freeze–thaw frequency environment of Beijing. Notably, specimens with high aerogel content demonstrated outstanding structural and functional durability. This study provides a theoretical foundation and practical guidance for incorporating aerogel in the optimized designs and applications of thermal insulation building materials in cold regions. Full article

Building facade insulation technologies have evolved from primitive thermal barriers to high-performance, multifunctional systems that enhance energy efficiency and indoor comfort. Historical insulation methods, such as thick masonry walls and timber-based construction, have gradually been replaced by advanced materials and innovative facade designs. Studies indicate that a significant proportion of a building’s heat loss occurs through its external walls and windows, highlighting the need for effective insulation strategies. The development of double-skin facades (D-SFSs), adaptive facades (AFs), and green facades has enabled substantial reductions in heating and cooling energy demands. Materials such as vacuum insulation panels (VIPs), aerogels, and phase change materials (PCMs) have demonstrated superior thermal resistance, contributing to improved thermal regulation and reduced carbon emissions. Green facades offer additional benefits by lowering surface temperatures and mitigating urban heat island effects, while D-SF configurations can reduce cooling loads by over 20% in warm climates. Despite these advancements, challenges remain regarding the initial investment costs, durability, and material sustainability. The future of facade insulation technologies is expected to focus on bio-based and recyclable insulation materials, enhanced thermal performance, and climate-responsive facade designs. This study provides a comprehensive review of historical and modern facade insulation technologies, examining their impact on energy efficiency, sustainability, and future trends in architectural design. Full article

In Saudi Arabia’s hot and arid climate, residential buildings account for over half of national electricity consumption, with cooling demands alone responsible for more than 70% of this use. This paper explores the hypothesis that contemporary villa designs are inherently inefficient and that current building regulations fall short of enabling adequate thermal performance. This issue is expected to become increasingly significant in the near future as external temperatures continue to rise. The study aims to assess whether passive design strategies rooted in both engineering and architectural principles can offer substantial reductions in cooling energy demand under current and future climatic conditions. A typical detached villa was simulated using IES-VE to test a range of passive measures, including optimized window-to-wall ratios, enhanced glazing configurations, varied envelope constructions, solar shading devices, and wind-tower-based natural ventilation. Parametric simulations were conducted under current climate data and extended to future weather scenarios. Unlike many prior studies, this work integrates these strategies holistically and evaluates their combined impact, rather than in isolation while assessing the impact of future weather in the region. The findings revealed that individual measures such as insulated ceilings and reduced window-to-wall ratios significantly lowered cooling loads. When applied in combination, these strategies achieved a 68% reduction in cooling energy use compared to the base-case villa. While full passive performance year-round remains unfeasible in such extreme conditions, the study demonstrates a clear pathway toward energy-efficient housing in the Gulf region. Full article

As energy-efficient buildings become central to climate change mitigation, the opportunity for interior and interstitial moisture accumulation and mould growth can increase. This study investigated the potential simulation-based mould growth risks associated with the current generation of insulated low-rise timber framed external wall systems within southeastern Australia. More than 8000 hygrothermal and bio-hygrothermal simulations were completed to evaluate seasonal moisture patterns and calculate mould growth potential for nine typical external wall systems. Results reveal that the combination of increased thermal insulation and air-tightness measures between the 2010 and 2022 specified building envelope energy efficiency regulations further increased predicted Mould Index values, particularly in cool-temperate climates. This was in part due to insufficient moisture management requirements, like an air space between the cladding and the weather resistive layer and/or the low-water vapour permeability of exterior weather resistive pliable membranes. By contrast, warmer temperate climates and drier cool-temperate climates exhibit consistently lower calculated Mould Index values. Despite the 2022 requirement for a greater water vapour-permeance of exterior pliable membranes, the external walls systems explored in this research had a higher calculated Mould Index than the 2010 regulatory compliant external wall systems. Lower air change rates significantly increased calculated interstitial mould growth risk, while the use of interior vapour control membranes proved effective in its mitigation for most external wall systems. The addition of ventilated cavity in combination with either or both an interior vapour control membrane and a highly vapour-permeable exterior pliable membranes further reduced risk. The findings underscore the need for tailored, climate-responsive design interventions to minimise surface and interstitial mould growth risk and building durability, whilst achieving high performance external wall systems. Full article

Adaptive façades, also known as climate-adaptive building shells (CABSs), could make a significant contribution towards reducing the energy consumption of buildings and their environmental impacts. There is extensive research on glazed adaptive façades, mainly due to the available technology for glass materials. The technological development of opaque adaptive façades has focused on variable-thermal-resistance envelopes, and the simulation of this type of façade is a challenging task that has not been thoroughly studied. The aim of this study was to configure and validate a simplified office model that could be used for simulating an adaptive façade with variable thermal resistance via adaptive insulation thickness in its opaque part. Software-to-software model comparison based on the results of an EnergyPlus Building Energy Simulation Test 900 (BesTest 900)-validated model was used. Cooling and heating annual energy demand (kWh), peak cooling and heating (kW), and maximum, minimum, and average annual hourly zone temperature variables were compared for both the Adaptive and non-adaptive validated model. An Adaptive EnergyPlus model based on the BesTest 900 model, which uses the EnergyPlus SurfaceControl:MovableInsulation class list, was successfully validated and could be used for studying office buildings with a variable-thermal-resistance adaptive façade wall configuration, equivalent to a heavyweight mass wall construction with an External Insulation Finishing System (EIFS). An example of the Adaptive model in the Denver location is included in this paper. Annual savings of up to 26% in total energy demand (heating + cooling) was achieved and could reach up to 54% when electro-chromic (EC) glass commanded by a rule-based algorithm was added to the glazed part of the variable-thermal-resistance adaptive façade. Full article

The challenge of thermally upgrading traditional stone masonry buildings is addressed through the analysis of a representative example typical of regional rural architecture in central Poland, constructed using soft silica limestone and clay mortar. These buildings, which form an important part of the local cultural heritage, are increasingly becoming the subject of interdisciplinary research and conservation initiatives. This study presents a detailed characterization of the materials and architectural features specific to this building typology. Thermal transmittance calculations were performed and analyzed, with the use of THERM 7.6.1.0 software enabling precise modeling of the wall’s heterogeneous structure. The physical and thermal properties of natural materials—particularly soft silica limestone and clay—were taken into account. The analysis included evaluation of the heat transfer coefficient, temperature distribution, and heat flux density for a reference wall model, as well as for variants with both internal and external insulation layers. The study explores thermal comfort and energy performance within the broader context of preserving and reusing historic rural buildings. Furthermore, the findings are discussed in relation to current European energy efficiency regulations and heritage protection frameworks. The scientific value of this work lies in its context-specific, material-sensitive methodology and in providing practical insight into balancing energy retrofitting with architectural conservation. Full article

The building sector is a major global energy consumer, particularly in Lebanon, where heating and air conditioning demand remains high. Integrating Phase Change Material (PCM) into building envelopes presents a promising solution for latent heat storage and enhanced energy efficiency. This study investigates the optimal wall configurations for improved thermal performance using PCM in two Lebanese regions: Beirut and Bekaa. Using ANSYS Fluent, various wall configurations were analyzed to determine the most effective placement of PCM. The optimal configurations were then evaluated in DesignBuilder to estimate energy savings. Results indicate that in Bekaa, external PCM and insulation provide the best performance due to strong dependence on external conditions, whereas in Beirut, internal PCM and insulation are more effective. PCM implementation in both regions significantly reduces energy consumption, with Bekaa proving more advantageous as it does not require additional cooling mechanisms. This research underscores the potential of PCM as a viable strategy for enhancing energy efficiency in building envelopes, with relevance to the climatic conditions of Beirut and Bekaa. Full article

In China, retrofitting rural dwellings is a crucial step toward enhancing living conditions and lowering energy waste. One of the most important ways to enhance building performance is to retrofit the building envelope. The Qianbei Region’s (Northern Guizhou Province, China) rural dwellings are the subject of this study. It identifies the persistent issue of inadequate thermal comfort in local rural dwellings through indoor thermal environment measurements and questionnaire surveys. Using a parametric modelling tool (Rhino-Grasshopper-Ladybug Tools), multi-objective optimization was performed using a non-dominated sorting genetic algorithm (NSGA-II), with the types of external windows, walls, and roof insulation as optimization variables, and building energy consumption (E), annual thermal discomfort hours (TDT), and life cycle cost increment (ΔLCC) as optimization objectives. After the retrofitting, the building’s energy consumption was reduced from the baseline value of 96.41 kWh/m² to 42.40 kWh/m² (a 56% reduction), and the annual duration of thermal discomfort decreased from 6173 h to 5078 h (a 17.7% decrease). This resulted in a positive economic return, with a cost saving of ΔLCC = −56,329.87 CNY. The research proposes a scientific method for the energy-saving retrofitting of rural dwellings in the Qianbei Region, which also serves as a guide for the optimization of building performance in comparable climate zones. Full article

In the tire manufacturing process, rubber compounds are vulcanized in volcanic presses. The vulcanization technology is carried out at temperatures above 150 °C, i.e., at a temperature potential that causes heat losses if the containers are not sufficiently insulated. The paper describes the mathematical model developed to detect the heat fluxes from the container walls to the surroundings. The calculation is carried out strictly in the SI system. With the help of the developed model, the back-relations of heat losses through the vertical and horizontal walls of the container enclosure were obtained as a function of the thickness of the insulation without and with a radiation shield on the inside of the enclosure. Numerical modeling using the finite volume method was used to verify the results obtained. In the numerical simulation, a 2D and a 3D model were created, and the same input conditions as in the mathematical model were simulated. Using the obtained results, an energy-energy balance of the tire vulcanization technology was performed by comparing the heat loss fraction as a function of the external temperature of the container cover and as a function of the insulation thickness. Full article

The urgent global mandate to achieve net zero carbon emissions by 2030 has accelerated innovation in sustainable construction materials, particularly natural insulation solutions. This study addresses persistent challenges such as complex production processes, non-compostable components, and limited adherence to industry standards by developing and evaluating a novel slim insulation panel made from agricultural waste, specifically wheat straw. Targeted at retrofitting Grade 2 listed dwellings in the UK—where external modifications are restricted—the panels combine simplicity, full compostability, and conformity with regulatory benchmarks. Prototypes were fabricated using wheat straw and two compostable binders, tested for thermal performance, moisture stability, and biodegradability using an innovative Actual Wall Replication Method (AWRM) to mimic real-world conditions. The findings demonstrated superior thermal conductivity and durability, with panels achieving significant energy-saving potential without compromising heritage integrity. The work highlights wheat straw’s viability as an eco-friendly insulation material and accentuates the necessity of realistic testing for accurate performance assessment. This study offers a replicable framework for integrating circular economy principles into heritage retrofitting, bridging the gap between ambitious environmental targets and historic building preservation, thereby contributing to broader sustainable development goals. Full article

A possible way to solve the problem of energy saving in construction is to introduce energy-efficient buildings at the design stage and, in particular, during retrofit. Therefore, the purpose of this study is to conduct a theoretical analysis of thermal resistance and energy loads on a building in cold climatic conditions. The study of these values was carried out in the ANSYS software package and the Maple computer algebra system, respectively. This study examines four types of structures: the existing facade of a building constructed in 1966, a traditional ventilated facade, and two designs featuring alternating insulation layers with enclosed air channels and with or without heat-reflecting screens in the insulation layer. The results of this study show that the new design incorporating heat-reflecting screens in the insulation layer is 1.15 times more energy-efficient in terms of thermal resistance than the proposed design without such screens. The effectiveness of the proposed new design with heat-reflecting screens in the insulation layer is also confirmed through an analysis of the thermal protection of the building, where the auxiliary indicators, specific characteristics, and complex values of energy efficiency and energy load of the building show greater efficiencies of 1.6, 1.03, and 1.05 times, respectively, compared to the other studied structures. The comprehensive research results presented in this study indicate that the use of energy-efficient wall structures for the retrofit of external enclosures can significantly improve the thermal performance of buildings. It was also determined that the use of such wall structures can significantly enhance the building’s overall energy efficiency rating. The findings of this study highlight that the proposed solutions can contribute to significant energy savings in buildings, while the newly developed structures can serve as valuable additions to the existing catalog of energy-efficient external wall designs. Full article