Search Results (1,850)

The growing demand for low-carbon building materials and the challenges of handling agroforestry waste and discarded EPS particles have spurred research toward developing novel building composites that utilize solid waste. Therefore, this study aims to develop a lightweight geopolymer composite incorporating these recycled materials to balance thermal insulation, mechanical strength, and waterproofing properties. In this work, geopolymer served as the binder, with various types of raw biomass (sawdust, rice husk, rice straw, and coconut fiber) as the primary aggregates and EPS particles as an additive to create a closed-pore structure. The microstructure of the raw biomass was characterized by SEM, while its specific surface area and average pore diameter were determined by BET analysis. Furthermore, the prepared composites were comprehensively evaluated in terms of their microstructure, pore structure (MIP), density, thermal conductivity, compressive strength, total water absorption, capillary water absorption, surface wettability, and UV aging behavior. The results showed that the prepared composites exhibited a porosity of 59.9–65.7%, a density of 492.9–586.3 kg/m³, a compressive strength of 7.3–10.9 MPa, a thermal conductivity of 0.115–0.142 W/(m·K), a total water absorption of 35.2–42.2%, capillary water uptake coefficients of 4.9–11 kg/m², and a water contact angle exceeding 140° (after modification). In addition, the developed composites offered significant environmental and economic benefits, with a low carbon footprint and an estimated cost of 100.6–150.3 USD/m³, making them more competitive compared to traditional insulation materials. Meanwhile, this study provides a scientific basis for developing high-strength building insulation materials from agroforestry waste, thus outlining a promising direction for future research and industry development. Full article

University dormitories in cold climate regions face the dual challenges of high heating energy consumption and poor outdoor pedestrian comfort during winter. Existing studies on university dormitories have primarily focused on individual building performance optimization, while insufficient attention has been paid to the optimization of dormitory cluster layouts and their multi-objective performance. To address this gap, this study establishes a parametric multi-objective optimization framework to simultaneously minimize building energy use intensity, minimize wind speed at pedestrian height, and maximize outdoor thermal comfort. Based on three floor area ratio scenarios, 24 dormitory prototypes are extracted from three building typologies: row-type buildings, detached buildings, and enclosed buildings. The optimization process was implemented on the Grasshopper platform using the NSGA-II algorithm. Cluster analysis is conducted on the Pareto front, and Pearson correlation analysis is applied to investigate the relationships between six urban morphological parameters and the three optimization objectives. The results indicate that: (1) enclosed buildings (E-1 type) and detached buildings (D-1 type) dominate the Pareto-optimal solution set; (2) high-FAR buildings are predominantly distributed in the northeastern part of the site, while public spaces are concentrated in the central-southern area; (3) correlation analysis indicates that shape coefficient (SC) exhibits the strongest correlations with the three objectives; and (4) compared with dominated solutions, Pareto-optimal solutions reduce WS by 10.46% and EUI by 6.57%, while improving UTCI by 0.05 °C. This study provides quantitative decision-making support for efficient planning and low-carbon design of university dormitory clusters in cold climate regions. Full article

The large-scale integration of wind and solar photovoltaic (PV) power is a cornerstone of low-carbon, sustainable energy systems. However, the uncertainty of the output brings great challenges to the operation and dispatching of power systems. To clearly describe the fluctuation characteristics of wind–PV power output and the spatial–temporal coupling relationship, a two-stage wind–PV scenario-generation method is proposed. This method is based on Difference-Constrained Variational Autoencoder and Mixture of Factor Analyzers (DVAE-MFA). In the first stage, a differential constraint term is added to the reconstruction loss of the Variational Autoencoder (VAE) to build the Difference-Constrained Variational Autoencoder (DVAE) model. This helps the model better learn the fluctuation characteristics of output sequences. In the second stage, to solve the problem of the posterior distribution of the DVAE latent variables deviating from the standard normal prior, the Mixture of Factor Analyzers (MFA) model is introduced for secondary probability modeling of the latent space. The simulation experiment results show that the proposed DVAE-MFA model outperforms comparison models in terms of the scenario temporal fluctuation characteristics, spatial–temporal correlations, and statistical distribution similarity. The generated output scenarios can reproduce the features of historical data, providing high-quality data support for the stochastic optimization scheduling of sustainable power systems. Full article

Accurate photovoltaic (PV) energy forecasting is vital for grid stability and the global low-carbon transition. However, existing data-driven and channel-independent PV energy forecasting models struggle to capture nonlinear meteorological couplings, heterogeneous physical scales across stations, and high-frequency non-stationary fluctuations. To address these limitations, this study proposes a Physics-Guided Cross-Variable Temporal Transformer architecture. Building upon a channel-independent foundation, we introduce a Cross-Variable Attention mechanism to explicitly reconstruct nonlinear photothermal couplings via dynamic attention weights. To resolve multi-station physical scale discrepancies, a Physical Feature-wise Linear Modulation network utilizes installed capacity as a static prior for adaptive cross-station scale alignment. During optimization, a Time Dynamics-Aware Perceiving Loss jointly penalizes absolute errors and first-order time differences, constraining the network’s tracking ability for transient ramping. Experiments demonstrate that the proposed architecture overcomes traditional channel-isolation limitations. The model achieves a 21.6% reduction in MSE compared to PatchTST, a 44.0% reduction compared to Autoformer, and a 2.7% improvement in R² over Informer. This provides an accurate, generalizable, and physically interpretable solution for collaborative multi-station distributed PV energy forecasting. Full article

Multistorey timber construction (MTC) is widely promoted for lowering embodied carbon, yet its uptake across Europe remains uneven. This study asks which drivers and barriers shape mid-rise wood buildings and how they differ across regions and stakeholders. We combine a structured literature review with a survey of 116 construction professionals across three deliberately contrasted national construction contexts. Belgium as an emerging market, Austria with a growing timber culture, and Norway as a mature policy-driven setting advancing timber. Respondents rated 31 literature-derived factors and 16 strategies. Across all contexts, respondents converge on a shared core: timber was perceived positively when it offered predictable project value, especially construction speed, image/marketing value, sustainability, and user-related benefits. Conversely, obstacles clustered around economic, technical, and legal uncertainty—especially building cost, fire performance, acoustics, conventional procurement, and path dependency. Country patterns suggest different priorities: Belgium may require increased ecosystem readiness, Austria standardisation and clearer regulatory interpretation, and Norway continued political support and market legitimacy. Stakeholder patterns further suggest differentiated support needs across architects, engineers, contractors, clients, suppliers, and verifiers. These findings explore MTC challenges and opportunities as contextual policy and industry priorities for empowering low-carbon construction and the circular economy transition in the built environment. Full article

Flexible organic solar cells (FOSCs) are a promising green energy technology due to their mechanical flexibility, light weight, low cost, and compatibility with large-area solution processing. Although the power conversion efficiency (PCE) of rigid organic solar cells has exceeded 20%, a significant performance gap remains for flexible devices, primarily constrained by the limitations of two key components: the flexible substrate and the transparent electrode. This review systematically summarizes recent research progress on flexible substrates, including ultrathin glass, polymer substrates, stretchable substrates, and bio-based substrates, and flexible transparent electrodes, including ITO, conductive polymers, carbon-based nanomaterials, ultrathin metal films, metal grids, and metal nanowire networks. Building on this, the review explores strategies for the synergistic design of substrates and electrodes, analyzing critical pathways for their co-optimization across four dimensions: interface engineering, mechanical compatibility, optical coupling, and process integration. Examining representative case studies from the literature, optimal substrate–electrode pairings for different application scenarios are summarized. Finally, the review outlines a future perspective on the evolution from compatibility toward functional integration, offering a systematic framework for the development of next-generation flexible photovoltaic devices that are efficient, stable, and adaptable to diverse application requirements. Full article

Sustainability certification schemes (SCSs) such as LEED, BREEAM, etc., are widely accepted as an effective tool for the promotion of sustainable design principles and lifecycle carbon reduction in building projects. Greece, despite having a relatively small real estate market, presents solid activity in this field, but the related research remains extremely limited. Following a comprehensive quantitative data analysis regarding the use of SCSs in Greece and Europe, this paper examines adoption determinants, challenges, and prospects in the Greek construction sector, drawing on semi-structured interviews. The findings show that LEED dominates the Greek market, and although the SCS benefits are well documented in the literature, the overall market demand is largely confined to office and commercial developments and constrained by affordability concerns, low market awareness, supply chain constraints, administrative complexity, and project coordination challenges. Nevertheless, as future prospects are positive overall, the research provides recommendations towards targeted actions for policy-makers, industry professionals, and other stakeholders. This can encourage supply chain development and accelerate certification uptake, thereby supporting national sustainability objectives and the implementation of European climate and energy policies. Full article

The decarbonization of industrial heating systems is one of the major challenges of the current energy transition. Gas-fired radiant tubes dominate industrial heating in large-span, high-bay buildings due to their high efficiency and low operating costs; however, the absence of equivalent electric solutions capable of replacing them represents a significant technological and scientific gap. This paper presents the design, construction, and experimental characterization of an innovative electric radiant tube prototype developed within the INFRAEL research project. The prototype consists of a 100 mm diameter steel tube housing nickel–chromium resistive elements in various configurations, powered from a 230 V AC supply. Thermal measurements were performed using Type K thermocouples distributed along the tube, a non-contact infrared thermometer, and thermovision imaging, complemented by MATLAB R2025bTrial-based interpolation for mapping the thermal field on a receiving plane placed 2 m below the tube. Experimental results show that at a total power of ~1.2 kW (two resistors in parallel), the tube surface reaches temperatures exceeding 250 °C, corresponding to medium-wave infrared emission (~4 μm). A single 630 W resistor yields surface temperatures of approximately 136–160 °C. The temperature distribution on the receiving plane is relatively uniform. The study identifies key optimization directions—resistor geometry, thermal insulation, and integration with photovoltaic sources—with the goal of developing a competitive, zero-carbon alternative to gas-fired radiant heating systems in industrial environments. Full article

Subterranean metro stations require substantial structural material inputs and can generate prolonged disruption in dense urban environments. Rather than assessing the environmental performance of an entire metro system, this study compares the embodied environmental impacts and surface-occupation effects of two representative underground station typologies from the Istanbul M7 Metro Line: a deep Top-Down station and a shallower Cut-and-Cover station. The proposed SECURE framework integrates Building Information Modelling (BIM)-based Life Cycle Assessment (LCA) with a Spatiotemporal Disruption Index (SDI), which is used as a physical proxy for cumulative surface occupation during construction. The assessment covers material production, transport, end-of-life processes, and recovery benefits in accordance with ISO 14040/14044, while excluding operational energy and on-site construction machinery from the comparative LCA boundary. The results show that the deep Top-Down typology requires 3.11 m³/m² of structural concrete, compared with 2.22 m³/m² for the Cut-and-Cover typology. Within the analysed cases, this higher structural material intensity is associated with a 54% increase in Global Warming Potential, from 9953.62 to 15,343.14 kg CO₂ eq/m². The difference primarily reflects the combined influence of excavation depth, station geometry, reinforced concrete volume, and permanent retaining elements, rather than the construction sequence alone. In contrast, the Top-Down typology substantially reduces modelled surface occupation, with cumulative SDI decreasing from 115,800 to 45,675 m²·month. These findings indicate a trade-off between embodied environmental burden and potential socio-spatial disruption. The study therefore suggests that early-stage metro station planning should evaluate excavation depth, structural mass, construction sequence, and surface continuity together. For deep urban stations where Top-Down construction is required, low-carbon cement substitution and localised material sourcing may help reduce material-related environmental impacts. Full article

Heat pumps are core equipment for efficient low-grade thermal energy utilization and low-carbon transformation of the energy structure, offering significant energy-saving potential in building heating and industrial waste heat recovery. This paper reviews the research progress and technical challenges of compression, absorption, and adsorption heat pumps as well as nanofluid-enhanced heat transfer technology and elastocaloric heat pump systems. Air source heat pumps can delay frosting through variable frequency, heat storage, and waste heat recovery. However, accurate prediction models for performance degradation under extreme cold conditions are lacking. Although ground source and water source heat pumps exhibit significant energy efficiency advantages, ground source systems may suffer from performance degradation due to underground thermal imbalance. The application of water source systems is strictly constrained by water resource conditions. Driven by low-grade waste heat, absorption heat pumps employing traditional working pairs suffer from crystallization, corrosion, or high rectification energy consumption. The COP of a single-effect cycle under 80~100 °C waste heat is only 1.2~1.9, while hybrid cycles can reach approximately 3.2 at 120~150 °C. Although adsorption heat pumps achieve significantly improved performance under continuous heat recovery cycles, the full-scale power density of novel adsorbents such as metal–organic frameworks is inferior to the power density of traditional silica gel. Moreover, under off-design conditions, the performance drops by 23~48% compared to theoretical values. Nanofluids can enhance heat transfer, but the long-term effects of particle agglomeration at high temperatures on pump power consumption and system compatibility remain to be systematically evaluated. Elastocaloric heat pump systems can achieve refrigerant-free cooling, but current prototypes still cannot compete with traditional vapor compression systems in long-cycle fatigue reliability and power density. Current heat pump technologies generally face challenges such as insufficient adaptability to extreme conditions, bottlenecks in working fluids and materials, and a lack of long-term validation. Future research must construct a multi-source coupling optimization system, address common problems in working fluids and materials, promote long-term validation and kilowatt-level prototype demonstrations, and drive the large-scale deployment and engineering application of heat pump technology toward high efficiency, intelligence, and high reliability. Full article

The building industry is central to climate change mitigation because it generates substantial energy use and carbon emissions across the full building life-cycle, from material production to operation. Passive and energy-efficient designs, renewable energy integration, use of low-carbon and reusable materials, digital optimization, and circular waste management can minimize operational and embodied emissions, and climate-responsive design can enhance heat, water stress, and other environmental resilience. This study explores sustainable construction practices and climate change mitigation strategies in four different economies: China, Malaysia, South Africa, and Peru. Based on questionnaire data collected from professional engineering and green building networks associated with the World Federation of Engineering Organizations (WFEO), the study applies thematic analysis to compare national priorities and strategies. The findings show that each country pursues sustainability according to its resources, development needs, environmental challenges, and technological strengths. China and Malaysia emphasize energy-efficient design and digital building systems, South Africa focuses on climate-responsive design and material recovery, while Peru prioritizes bio-based materials and local solutions. Overall, renewable energy, circularity, resource optimization, and digital technologies emerge as key trends in advancing low-carbon, climate-resilient construction. Full article

Rapid and reliable prediction of embodied carbon emissions is essential for supporting sustainable design decision-making and reducing the environmental impacts of building engineering projects. However, existing studies have mainly focused on single buildings, with limited attention to project-level prediction and variations in information availability across design stages. To address this gap, this study developed a machine learning framework for project-level embodied carbon prediction based on a dataset of 78 projects involving 426 individual buildings. Using project attributes, scale indicators, structural characteristics, material quantities, and construction-related information, nine machine learning models were developed for the schematic design stage and the construction drawing design stage. Two residual-corrected weighted ensemble models were further introduced to improve predictive performance. The results show that the Extra Trees–KNN residual-corrected weighted ensemble model achieved the best performance at the construction drawing design stage, with a test-set R² of 0.949. SHAP analysis further revealed a stage-dependent shift in dominant drivers: gross floor area and land area dominated at the schematic design stage, whereas concrete and reinforcement quantities became the leading predictors at the construction drawing design stage. The proposed framework provides interpretable and stage-specific quantitative support for low-carbon design decision-making, thereby facilitating embodied carbon reduction and the transition toward a more sustainable built environment. Full article

Improving the operational energy and carbon performance of hotel buildings is an important environmental dimension of sustainable building design. This study develops a reproducible EnergyPlus-based framework that combines parametric simulation, interpretable sensitivity analysis, machine learning surrogates, and carrier-resolved operational carbon accounting for Beijing hotel buildings. From 20,000 Latin hypercube candidates, input-side physical and functional screening retained 4640 successful EnergyPlus simulations. The simulated EUI mean was 140.6 kWh/(m²·a), 14.3% above the published Beijing hotel mean; surrogate performance is therefore interpreted as fidelity to the simulator rather than direct measured-building prediction. SRC with bootstrap uncertainty and a SHAP cross-check identified the main domestic-hot-water, building-form, and HVAC drivers. Of 17 models, Poly3-RidgeCV achieved the highest held-out fidelity (R² = 0.9976; RMSE = 1.72 kWh/(m²·a)). Baseline OCEI averaged 48.20 kgCO₂e/(m²·a); EUI and OCEI were strongly correlated (r = 0.954) but not interchangeable, with 71.8% overlap between the top-10% low-EUI and top-10% low-OCEI cases. Emission-factor scenarios showed robust but non-static energy-carbon coupling. The framework supports early-stage comparison of energy-efficient alternatives with comparatively lower operational carbon emissions within the stated accounting boundary, contributing to sustainable hotel design without constituting a whole-life or measured-building sustainability assessment. Full article

The preservation of twentieth-century reinforced concrete buildings increasingly requires the integration of structural engineering assessment with heritage conservation principles. Although the deterioration mechanisms of reinforced concrete in marine environments have been extensively investigated, relatively few studies have examined how advanced material degradation affects the technical feasibility of preserving modern reinforced concrete heritage structures. This study addresses this gap through the structural assessment of the Patras Port Authority Building (OLPA), a reinforced concrete building constructed in the early 1970s and exposed for more than five decades to an aggressive coastal environment, providing the engineering basis for determining whether a complete code-based structural assessment is justified in accordance with KAN.EPE. and EN ISO 13822. A comprehensive inspection and testing program was carried out, including visual inspection, crack mapping, concrete core testing, carbonation-depth measurements, pH determination, chloride-content analysis, half-cell potential measurements, electrical resistivity measurements, and selective exposure of reinforcement. The engineering assessment revealed extensive deterioration of the structural system, including low concrete strength (approximately C8/10), carbonation exceeding the concrete cover, pH values between 7 and 8, chloride concentrations ranging from 0.0377% to 0.8975% by cement mass, and severe reinforcement corrosion. The measured average cross-sectional loss reached 34.5% for longitudinal reinforcement and 65.6% for transverse reinforcement (stirrups), accompanied by significant reductions in mechanical properties and ductility. It should be noted that concrete samples for chloride determination were collected at depths well beyond the reinforcement level. Additional deficiencies associated with inadequate confinement reinforcement, outdated seismic detailing, previous earthquake damage, cracking in columns and shear walls, and uncertainty regarding the geometry and condition of the foundation system further increase structural vulnerability. The engineering assessment indicates that the combined effects of long-term environmental exposure, corrosion-induced deterioration, obsolete design provisions, and existing structural deficiencies substantially reduce the reliability and seismic performance of the load-bearing system. Within this context, the study examines the implications of advanced deterioration for the preservation of reinforced concrete heritage buildings and proposes an integrated assessment framework that combines structural safety, durability, material integrity, intervention feasibility, and heritage significance. The proposed approach contributes to a more comprehensive engineering-based methodology for evaluating preservation strategies for aging reinforced concrete buildings exposed to aggressive marine environments. These findings also raise important concerns regarding the technical feasibility of preserving ageing reinforced concrete buildings located in highly seismic regions, where ensuring structural safety may require the introduction of new load-bearing elements together with the replacement of a substantial portion of the already deteriorated original material. Full article

Against global dual-carbon targets, urban residential central heating dominates building energy use and carbon emissions. Conventional LSTM forecasting requires manual hyperparameter adjustment and easily falls into local optima; micro-community carbon prediction also lacks accurate energy models and policy-based multi-scenario analysis for targeted low-carbon renovation. This study adopts the 2018–2023 hourly heating data of a community in H Province. It builds a preprocessing workflow with boxplot-Isolation Forest anomaly detection and MissForest filling, then constructs an SSA-LSTM hybrid model optimized by Sparrow Search Algorithm to predict heat and power loads precisely. Combined with carbon accounting and three policy scenarios, it evaluates carbon peak timing and emission reduction potential of heating renovations. Results show that SSA-LSTM attains 2.48% MAPE for heat and 3.20% for power, surpassing LSTM and BP. Only moderate and ideal renovation scenarios realize carbon peaks in the 2023–2024 heating period, with cumulative cuts of 138.19 t and 254.2 t by 2031–2032; household heat meters deliver 28% of total reductions. The framework offers quantitative support for community heating operation, renovation evaluation and carbon quota management. Full article