Search Results (1,266)

Waste prevention begins upstream, in decisions made long before a product becomes waste. This article examines product lifetime management as an upstream environmental strategy and asks when longer product use can reduce waste generation, resource consumption and environmental impacts across the life cycle. An integrative literature review combined exploratory searches in Google Scholar and citation tracking with a structured search of Scopus. Records were screened by title, abstract and keywords. Publications in English were considered without a date limit and selected according to their relevance to product lifetime, premature replacement, repair and lifetime extension, consumer and business decisions, regulation, waste prevention and life cycle assessment. The selected studies were supplemented with relevant legal, regulatory, institutional and standardisation documents, producing a final reference base of 240 sources. The review shows that actual product lifetime is shaped not only by technical durability, but also by repairability, access to spare parts and information, continued software and service support, opportunities for upgrading and reuse, business incentives and consumer behaviour. Extending product use can reduce waste and resource demand, but environmental benefits are not automatic. They depend on product characteristics, energy consumption, technological progress and, above all, whether prolonged use genuinely replaces the production and purchase of new products. Product lifetime management should therefore be understood as a coordinated upstream strategy linking design, repair, reuse, business models, regulation and consumption with environmental assessment across the life cycle. Full article

Orange waste (OW) is an example of biomass that has a potential for nutrients and energy recovery. However, its use in biological processes, e.g., anaerobic digestion (AD), still poses a significant technological challenge due to the presence of hardly biodegradable lignin and compounds toxic to the microorganisms. To release its energetic potential, the use of an adequate pre-treatment method might be a solution. This research evaluated the efficacy of various pre-treatment strategies, i.e., acoustics (AC) and hydrodynamic cavitation (HC), microwave radiation (MR), and the impact of solidified carbon dioxide (SCD) in improving the properties of OW, including organic compound content, fiber components, morphological structure, and generation of toxic intermediates. The obtained results showed that HC might be considered as the most efficient pre-treatment strategy prior to its further AD decomposition. For this strategy, an over 2-fold increase in biodegradability index, expressed as the DOC/TOC (dissolved to total organic carbon) ratio, was found. In turn, the other analyzed parameters, i.e., removal of organic compounds and delignification degree, were established at the favorable level of 63 and 56%, respectively. This effect was achieved with the lowest energy demand of 0.35 MJ/kgVS. However, HC favored the generation of AD inhibitors. However, to fully assess the impact of selected methods on AD performance, further experiments should be conducted. Full article

Indoor exposure to fine particulate matter (PM2.5) is a major environmental-health concern in Northern China, where severe ambient pollution, coal-based district heating and diverse residential building stocks coexist. Previous studies have been constrained by small numbers of independent residences, limited geographic coverage, and predominantly pairwise (bivariate) analyses. This study presents a seasonal monitoring campaign covering 48 residences across eight Northern Chinese cities. Paired indoor and outdoor PM2.5 was measured at 5 min intervals and aggregated to 31,094 valid hourly observations (from 32,256 scheduled hourly slots after exclusion of 1162 h with missing or invalid 5 min readings) over seven consecutive days in four seasons, alongside building, behavioural and meteorological covariates. Because repeated hourly measurements are clustered within residences, the primary analysis is a linear mixed-effects model (LMM) with a residence-level random intercept and a first-order autoregressive residual structure (marginal R² = 0.71; conditional R² = 0.91; intra-class correlation = 0.34), supported by ordinary-least-squares (OLS) models with CR2 finite-cluster-robust standard errors and a daily average sensitivity analysis. Adjusted LMM coefficients indicate that outdoor PM2.5 (β = 0.872, p < 0.001), window-open fraction (β = 0.548, p < 0.001) and cooking events (β = 0.046, p < 0.001) were positively, and air-purifier operation (purifier-on fraction β = −0.902, p < 0.001) was negatively, associated with indoor PM2.5; continuous purifier operation was associated with 59.4% lower indoor PM2.5 (an observational association, not a causal effect). Building-level infiltration factors (F_inf) averaged 0.28 ± 0.15. Estimated outdoor contributions to indoor PM2.5 ranged from 54.8% to 66.3% across an assumed penetration factor of p = 0.6–1.0 (60.7% at p = 0.8), peaking in the heating season. The mass-balance analysis estimated a median deposition rate of 0.53 h⁻¹ and a median air change rate of 0.52 h⁻¹ (window-open periods > 2 h⁻¹); these are model-derived, not directly measured quantities. These findings provide multivariable, cluster-aware evidence for envelope airtightness, informed window operation and correct air-purifier use to reduce residential PM2.5 exposure in Northern China. Full article

Seasonal energy storage effectively addresses seasonal electricity supply–demand imbalances. This study proposes a cross-seasonal compressed air energy storage system using a depleted gas reservoir as the storage reservoir. A six-stage compression–expansion system with intercooling and reheating is designed. Also, the heat of compression is recovered for district heating, and the expansion of cold energy is for cooling supply, thereby avoiding cross-seasonal heat storage costs. For the YD1 depleted gas reservoir case, the system achieves a round-trip efficiency of 57.85% and an exergy efficiency of 70.9%. The total energy utilization ratio, which represents the combined utilization of the electricity, heating, and cooling outputs relative to the corresponding energy input, reaches 166.6%. Incorporating revenue from the heating and cooling sales, the dynamic payback period is 2.38 years, and the investment recovery ratio reaches 4.40. Parametric analysis indicates that thermodynamic performance improves with the increase in discharge pressure and decrease in discharge power. Economic performance improves with longer daily operating hours and plant lifetime. This study demonstrates that depleted gas reservoirs combined with well-designed surface combined cooling, heating, and power systems offer a new research and development direction for large-scale, long-duration seasonal storage, facilitating renewable energy integration and grid stability. Full article

This study presents the FlowPCM concept, a mobile thermal energy storage (M-TES) system based on encapsulated phase change material (PCM) for waste heat recovery and potential integration with district heating and local heat supply systems. Unlike conventional M-TES solutions with stationary PCM beds, FlowPCM uses capsules containing ferromagnetic elements, enabling their magnetic handling and potential direct-contact charging in selected waste heat streams. The study combines a state-of-the-art comparison, capsule design and packing assessment, preliminary thermal calculations, and laboratory magnetic interaction tests. For the analysed industrial waste streams at 70–90 °C, the available thermal potential substantially exceeded the nominal storage capacity of a single FlowPCM unit (7.2 GJ), indicating that heat availability would not be the limiting factor in the considered application. Preliminary magnetic tests confirmed capsule attraction and lifting using permanent magnets. Depending on the magnet configuration, the first observable capsule interaction occurred at approximately 85–110 mm, while effective attraction suitable for practical handling occurred below approximately 50–60 mm. These results provide preliminary support for the technical feasibility of magnetically assisted capsule handling; however, direct-contact charging, long-term capsule durability, thermal performance, and magnetic recovery under representative industrial conditions still require experimental validation. Full article

This study assesses roadside grass biomass harvesting and allocation to collection centers using spatially explicit methods for preliminary district-heating supply-chain planning. Road-network data combined with mowing data for county roads were used to estimate theoretical, technically recoverable, and annual energy potentials in Kołobrzeg County, Poland, while high-resolution aerial imagery was used to identify roadside sections where biomass cannot be harvested, such as bridges, paved shoulders, gravel surfaces, and bicycle paths. Dijkstra’s algorithm calculated shortest network distances, after which a custom assignment procedure allocated road nodes and associated biomass to collection centers using either the baseline distance-based rule or its capacity-constrained extension. The estimated annual energy potential ranged from 14.9 to 38.1 TJ/a among the analyzed municipalities. In the two-center scenarios, the number of nodes assigned to the southern center increased from 25 under its $3000\mathrm{t}$ limit to 41 under equal $5875\mathrm{t}$ limits at both centers. The results show that combining aerial-image interpretation, biomass-to-energy estimation, and network-based allocation provides a transparent framework for identifying priority collection areas and organizing roadside biomass transport. The proposed workflow can support local authorities in preliminary biomass supply-chain planning and can be adapted to other regions with suitable spatial data. Full article

In district heating systems where radiators and floor radiant heating terminals coexist, the high-temperature supply water must be cooled by mixing with return water before delivery to underfloor heating terminals. However, overheating frequently occurs at these terminals in practice. Taking the mixing water system for underfloor heating terminals as the research object, this study develops a required mixing ratio model and a coupled hydraulic–thermal model to investigate the underlying overheating mechanism. The results show that the supply control valve has reached its lower regulation limit, and the actual mixing ratio remains below the target value—this mismatch is identified as the primary cause of terminal overheating. Quantitative analysis reveals that the original system exhibits temperature deviations of 3.5–6.0 °C under proximal high-pressure conditions and 1.6–2.1 °C under distal low-pressure conditions. To resolve this issue, three graded retrofit schemes are proposed: supply valve parameter enhancement (Scheme A), three-way valve scheme (Scheme B), and dual-valve scheme (Scheme C). Simulation results indicate that Scheme B reduces the temperature deviation to within ±0.5 °C under distal conditions, while Scheme C achieves the same under proximal conditions. Economic analysis indicates that, under the precondition that temperature control requirements are satisfied, the recommended schemes yield static payback periods of 3.8 years for mild overheating with Scheme A, 3.9 years for moderate overheating with Scheme B, and 4.1 years for severe overheating with Scheme C. A field case study of Scheme A demonstrates that the supply water temperature deviation is reduced from approximately 2.0 °C to within 0.5 °C under low-load conditions, confirming the effectiveness of the valve enhancement strategy. Due to current field constraints, the experimental validation is limited to Scheme A, while Schemes B and C are evaluated through the validated simulation model. The findings offer a quantitative reference for overheating diagnosis and retrofit selection in existing mixing water systems for underfloor heating terminals. Full article

Green hydrogen production through water electrolysis is a key pathway to the decarbonization of future energy systems. However, part of the electrical input is transformed into waste heat. In this study, alkaline, proton-exchange membrane, anion-exchange membrane, and solid oxide electrolysis systems are compared in terms of operating temperature, heat generation, heat transfer medium, and integration constraints. Reported COP values for commercial high-temperature vapour-compression heat pumps range from 2.4 to 5.8, depending on operating conditions. The heat-pump technologies reviewed include vapour-compression systems with single-stage, multistage, cascade, and transcritical configurations, together with absorption and adsorption systems, with a focus on suitable working fluids and practical limitations. The review distinguishes between direct heat recovery and heat recovery assisted by heat pumps, and it identifies two main areas of application: external supply for district heating, industrial consumers, and energy communities; and internal support for feedwater preheating, water cycle integration, and steam generation. A selection framework is proposed in which source- and sink-temperature compatibility determines thermodynamic feasibility, COP characterizes heat-pump performance, and LCoH supports techno-economic comparison. Direct heat recovery should be preferred when temperatures are compatible, while heat pumps can operate as enabling technologies when temperature upgrading is required and system-level economic and environmental performance remains advantageous. Full article

Urban waterfront spaces play an increasingly important role in mitigating urban heat and supporting climate-resilient urban development. However, previous studies have primarily focused on individual waterfront sites or local microclimatic simulations, with comparatively limited understanding of how waterfront morphology is associated with land surface temperature across different urban functional districts and spatial scales. This study evaluates the thermal characteristics of fifty representative waterfront samples in Chengdu, China, covering five urban functional districts: commercial, office, residential, park, and suburban areas. Land surface temperature (LST) data for the period from 1 June to 30 September 2023 were integrated with GIS-derived morphological indicators, including river width, water area ratio, green space ratio, building density, and distance to water. Thermal conditions were analysed within the 200 m waterfront zone and across 500 m, 1000 m, and 2000 m buffer zones. Correlation analysis, standardized multiple linear regression, and spatial autocorrelation analysis were used to assess bivariate relationships, independent predictor effects, and the robustness of the statistical results. The results show significant thermal differences among waterfront typologies. Commercial waterfronts exhibited the highest LST, whereas suburban waterfronts showed the lowest temperatures within the immediate waterfront zone. Standardized multiple regression analysis confirmed building density as the strongest independent positive predictor of LST across all spatial scales after accounting for intercorrelations among predictors, with adjusted R² values ranging from 0.384 to 0.582. River width and the water area ratio were negatively associated with LST mainly within the immediate waterfront zone, whereas the green space ratio showed no statistically significant independent association with LST. Cooling-related thermal contrasts also varied among waterfront typologies across buffer distances; however, inter-typology differences at the 2000 m scale were not statistically significant and should therefore be regarded as preliminary. Spatial autocorrelation analysis further indicated that the principal morphology–LST relationships remained broadly stable after accounting for spatial dependence. These findings suggest that waterfront thermal conditions are strongly associated with the combined configuration of blue, green, and built-environment characteristics rather than with water-body size alone. The multi-scale analytical framework provides a practical basis for evaluating waterfront thermal conditions, while the planning implications should be interpreted as directional rather than as fixed design thresholds. Full article

Jujube is an important economic fruit tree in China, with Xinjiang being the largest production region, where flowering-stage heat stress threatens yield stability. Assessing heat risk in jujube orchards requires consideration of crop-specific phenological sensitivity and heat injury thresholds. Therefore, this study developed a Heat Injury Accumulating Index for jujube (HIS_j) to assess flowering-stage heat injury by integrating temperature–humidity stress and phenological sensitivity. A Hazard–Vulnerability–Exposure framework combined with Landsat image was applied for spatial heat risk assessment, atmospheric circulation analysis and interpretable machine learning were integrated to identify the drivers of hazard and vulnerability. Results show that HIS_j exhibited pronounced spatial heterogeneity and a distinct spatial dipole-like pattern, with higher values mainly concentrated in the oasis regions of eastern and southern Xinjiang, and an approximately six-year oscillation across most regions. High risk areas were mainly concentrated in Turpan, Yizhou District, and southern Bazhou, whereas Aksu, Kashgar, and most of Hotan were predominantly characterized by moderate-risk conditions. Climatic heat hazard and integrated orchard-scale risk were not spatially equivalent, with some intensively managed orchard areas exhibiting comparatively lower risk despite relatively strong meteorological heat stress. Variations in HIS_j were associated with the Western Pacific Subtropical High, Eurasian zonal circulation, and the India–Burma trough. NDVI was used as an observational proxy for orchard vegetation condition to characterize vegetation-based vulnerability. NDVI showed nonlinear associations with hydrothermal conditions and elevation, with threshold-like responses around 0.10–0.15 cm³/cm³ for soil moisture and around 800 m for elevation. The relatively weak and non-monotonic SHAP contribution of HIS_j to NDVI suggests that the association between meteorological heat stress and orchard vegetation conditions may vary with local environmental conditions. These findings provide a spatially explicit basis for understanding flowering-stage heat risk and supporting targeted adaptation in arid oasis jujube orchards. Full article

Buildings account for roughly 37% of energy-related CO₂ emissions, and space cooling already consumes nearly 10% of global electricity. Cooling demand is rising fastest in tropical cities, where air-conditioning could reach 45% of peak load, especially in India by 2050. This review critically examines thermal energy storage (TES) as a flexibility resource across three distinct scales: individual buildings, district heating and cooling networks, and city-level multi-energy systems. Using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-based search of Scopus, Web of Science, and IEEE Xplore with primary and supplementary strings, 4447 records were identified, of which 174 were included. Each quantitative study was classified by validation level (simulation, laboratory, pilot, or operational) and by the centrality of thermal storage. Sensible, latent, and thermochemical storage technologies are compared using energy density (10–500 kWh/m³), efficiency (40–95%), cycle stability, and technology readiness. The review then evaluates the role of artificial intelligence (AI), machine learning, and Internet of Things platforms in forecasting, predictive control, and operational optimization of TES networks. Thirteen method families, grouped into AI and machine learning methods, optimization methods, control methods, and digital enabling technologies, are assessed against six explicitly defined criteria with evidence-coded scores. Among 47 quantitative studies, 37 (78.7%) are simulation-only, and only four (8.5%) report operational data. Direct TES-AI studies report simulated energy savings of 8–64% and peak load reductions of about 35%, whereas field-validated intelligent control reports 17% energy savings in a single real building experiment. The review also identifies inherent drawbacks of artificial intelligence-based operations, including limited interpretability, high data and computational demands, concept drift, and cyber vulnerabilities that increased peak electric load by 17.4% in a simulated attack. A structural imbalance in the literature is evident: most validated deployments remain at the building-scale, whereas urban-scale evidence is confined to district cooling, aquifer and pit storage, and multi-energy hub studies; no study reports the coordinated operation of distributed TES assets across multiple districts. A conceptual framework and a staged roadmap linking building, district, and urban scales are proposed. Priority research needs include urban-scale pilots in tropical climates, techno-economic assessment, interpretable and drift-robust AI, and interoperability standards that support United Nations’ Sustainable Development Goals 7, 11, and 13. Full article

The study investigates the efficacy of various Urban Heat Island (UHI) mitigation measures within the United Nations Educational, Scientific and Cultural Organization UNESCO-listed historical center of Florence. Increasingly frequent and severe heatwaves during the summer season represent significant challenges for urban sustainability and public health in the outdoor urban environment. Using ENVI-met as a simulation tool, the research assesses the current microclimate conditions of a district within a historical center and simulates alternative mitigation scenarios. It quantifies the benefits in terms of microclimate characteristics (Potential Air Temperature-Ta and Mean Radiant Temperature-MRT) and human comfort indexes (Physiological Equivalent Temperature-PET and Universal Thermal Climate Index-UTCI). The proposed interventions include blue and green infrastructures as well as shading systems installed across the district. Current climate conditions are characterized by an average Ta of approximately 32 °C and MRT exceeding 59 °C; consequently, the analyzed area falls into the very strong heat stress category for both the calculated comfort indexes. All evaluated mitigation measures result in improving microclimate conditions as well as enhancing human thermal wellbeing within the outdoor environment. The most effective district-level intervention is the installation of shading fabrics, which reduces average Ta by 0.2 °C and MRT by up to 14 °C compared to the current scenario. Interventions tailored for the main square significantly reduce both UTCI and PET values, shifting the thermal stress from very strong to strong or even moderate. These findings highlight the potential of localized and tailored interventions to successfully integrate climate mitigation strategies within sensitive historic urban districts. Full article

The European Union has set an ambitious goal of achieving net-zero emissions by 2050, and 90% reduction by 2040, through its Green Deal policy. A promising solution to this challenge lies in the adoption of Fifth-Generation District Heating Networks (5GDHNs) that operate at low temperatures, collecting and distributing heat from diverse sources (energy geostructures, asphalt pavement solar thermal collectors, industrial waste heat and waste heat from buildings’ cooling plants). The system’s design allows for heat storage underground, primarily during summer months, with distribution occurring via pipelines during winter. As part of the REHEAT project, a study has been conducted focusing on a simulation model developed using TRNSYS software. This model incorporates solar thermal collectors installed beneath the parking area asphalt pavements as a thermal energy source, coupled with a borehole thermal energy storage system. The setup is designed to meet the heating and cooling demands of a multiplex cinema situated in Northern Italy. The study presents the optimization of the system, reporting the monthly and annual data on energy balances and system efficiency. The findings demonstrate significant energy savings when compared to traditional heating and cooling systems (50.6% non-renewable primary energy reduction) and even greater CO₂ emission reduction (63.2%). Also, the economic analysis reveals positive results both from the point of view of operating costs and taking into account investment costs, highlighting the potential of 5GDHN as a sustainable solution for urban energy needs for a real case as the main novelty of this study. Full article

Heating and cooling account for roughly half of EU final energy demand, yet the decarbonisation of community-led district heating remains underrepresented in the finance literature. This paper examines the financial viability of heat cooperative business models through a three-model typology (administrative, leasing, asset) developed within the HeatCOOP project, applied to a financial feasibility analysis of two Slovenian biomass district heating projects. Both adopt the asset model via a public–private concession framework; capital expenditures range from €617,000 to €1.87 million and annual heat delivery from 1100 to 3300 MWh. Sensitivity analysis across grant rates of 0–65% shows that the subsidy rate is the dominant financial viability determinant: all four variants achieve positive net present value and internal rate of return of 7.3–7.8% at approximately 45% subsidy, while none are viable without public co-financing. The levelised cost of heat ranges from 85–97 €/MWh on a private basis to 114–134 €/MWh on an unsubsidised full-cost basis. Comparison with fourteen European benchmark cases shows that public subsidy functions not as a market-failure correction but as a structural substitute for cooperative member capital in environments where the cooperative tradition is nascent—with direct implications for subsidy programme design targeting cooperative district heating. Full article

Ground source heat pump (GSHP) systems contribute to sustainable building decarbonization while confronting two intertwined challenges: long-term ground thermal imbalance in shallow borefields and the requirement for coordinated operation between thermal systems and electrical grid dynamics. Hybrid shallow–deep borefield configurations have been proposed to mitigate thermal imbalance for sustainable geothermal resource exploitation, yet their grid-interactive demand–response potential remains unexplored. Here, we develop a coupled thermal–electrical model for a shallow–deep mixed GSHP (SDBHE) system equipped with water-tank thermal storage, validated against scaled sand-tank experiments (3.5–8.3% error), and assess its year-round performance under time-of-use electricity tariffs for a 200,000 m² residential district in cold-climate conditions. The SDBHE system reduces the required shallow borehole count by 28% and total drilling length by 22% compared with a shallow-only baseline, saving 11% on operational electricity costs over 10 years. Integrating water-tank thermal storage with a 50% load-shifting strategy yields an additional 10.9–11% cost reduction without degrading the system’s coefficient of performance. Under higher load-shifting ratios, the combined capital and operational savings reach 19–29%, with the optimal allocation assigning the incremental high-price-period load preferentially to deep boreholes (COP 6.29 versus 5.25 for shallow). These results demonstrate that integrating shallow and deep geothermal tiers with thermal storage enables both capital-efficient borefield design and economically viable demand-side grid participation. The findings are bound by the cold-climate residential context and the rule-based control scheme; field-scale validation and lifecycle cost analysis are needed to generalize the conclusions. Full article