Search Results (814)

Biomimetic structures inspired by evolutionary optimized biological systems offer promising solutions to overcome current limitations in passive daytime radiative cooling (PDRC) technology, which efficiently scatters solar radiation through atmospheric windows and radiates surface heat into space without additional energy consumption. While structural biomimicry provides excellent optical performance and feasibility, its complex manufacturing and high costs limit scalability due to micro–nano fabrication constraints. Material-based biomimicry, utilizing environmentally friendly and abundant raw materials, offers greater scalability but requires improvements in mechanical durability. Adaptive biomimicry enables intelligent regulation with high responsiveness but faces challenges in system complexity, stability, and large-scale integration. These biologically derived strategies provide valuable insights for advancing radiative cooling devices. This review systematically summarizes recent progress, elucidates mechanisms of key biological structures for photothermal regulation, and explores their application potential across various fields. It also discusses current challenges and future research directions, aiming to promote deeper investigation and breakthroughs in biomimetic radiative cooling technologies. Full article

In arid countries like Oman, fan–pad cooling systems are commonly used in greenhouse cultivation. However, in such harsh environmental conditions, a fan–pad cooling system can be inefficient, result in high water and energy consumption, and may cause plant and soil pathogens issues. To address these challenges, this study evaluated the technical performance of a greenhouse designed with the new concept of an on-grid, solar-powered, and fan-chiller tube bank (FCTB) cooling system, focusing on water use efficiency (WUE) and energy use efficiency (EUE) following pot-grown okra. In addition, greenhouse gas (GHG) emissions and financial aspects were evaluated through cost–benefit and cash flow analyses. This research was conducted with a Quonset side-walled single-span greenhouse equipped with a solar-powered FCTB cooling system and automatic scheduled irrigation system. Water and electricity consumption was recorded, and surplus energy supplied to the electricity grid was estimated. The greenhouse efficiencies were evaluated by computing the EUE, total WUE, cooling water use efficiency (CWUE), and irrigation water use efficiency (IWUE). The solar-powered FCTB greenhouse enhanced EUE, achieving a value of 1.16 and a positive net energy of 163.87 MJ·m⁻². The WUE, CWUE, and IWUE were 0.91 kg·m⁻³, 1.63 kg·m⁻³, and 2.07 kg·m⁻³, respectively. The economic assessment showed that okra cultivation with a solar-powered FCTB cooling system was economically unfeasible, as indicated by a benefit–cost ratio of 0.88. However, cucumber (IRR 46%, NPV 2.13 × 10⁴ USD) and cherry tomatoes (IRR 38%, NPV 1.98 × 10⁴ USD) demonstrated economic feasibility as supported by positive net present value (NPV) and the internal rate of return (IRR) values. Furthermore, incorporating solar energy with the FCTB cooling system enhanced the greenhouse’s sustainability, efficiencies, and profitability. This study recommends further research with this system for Oman’s seasonal effect with high-value crops and optimizing the size of the solar panel system to see how the energy and other efficiency components will vary. Full article

Community Earth System Model-Large Ensemble (CESM-LE) simulations are used to partition the Surface Air Temperature (SAT) trends over East Asia into the contribution of external forcing factors and internal variability. In the historical period (1966–2005), the summer SAT trends display a considerable diversity (≤−2 °C to ≥2 °C) across the 35 member ensembles, while under the RCP8.5 scenario, the region is mostly dominated by a strong warming trend (~1.5–2.5 °C/51 years) and touches the ~4 °C mark by the end of the 21st century. In the historical period, the warming is prominent over the Yangtze River basin of China, while under the RCP8.5 scenario, the warming pattern shifts northward towards Mongolia. In the historical period, the Signal-to-Noise Ratio (SNR) is less than 1, while it is higher than 4 under the RCP8.5 scenario, which indicates that, in the early period, internal variability overrides the forced response and vice versa under the RCP8.5 scenario. In addition, over much of the East Asian region, the chances of cooling are relatively high in the historical period, which partially counteracted the warming trend due to external forcing factors. In contrast, under the RCP8.5 scenario, the chances of warming reach ~100% over East Asia due to contributions from the external forcing factors. The novel aspect of the current study is that, in the negative phase (from the mid-1960s to ~2000), the Atlantic Multidecadal Oscillation (AMO) accounts for ~70–80% of the cooling trend or the SAT variability over East Asia, and thereafter, natural variability exhibits a slow increasing trend in the future. However, the contribution of external forcing factors increases from ~55% in 2000 to 95% in 2075 at a rate much faster than natural variability, which is primarily due to increasing downward solar radiation fluxes and albedo feedback on SAT over East Asia. Full article

Achieving net-zero emissions in arid and high-solar-yield regions demands innovative, cost-effective, and scalable energy technologies. This study conducts a comprehensive techno-economic analysis and assessment of a novel hybrid photovoltaic–thermal solar collector (U.S. Patent No. 11,431,289) that integrates a reverse flat plate collector and mini-concentrating solar thermal elements. The system was tested in Qatar and Germany and simulated via a System Advising Model tool with typical meteorological year data. The system demonstrated a combined efficiency exceeding 90%, delivering both electricity and thermal energy at temperatures up to 170 °C and pressures up to 10 bars. Compared to conventional photovoltaic–thermal systems capped below 80 °C, the system achieves a heat-to-power ratio of 6:1, offering an exceptional exergy performance and broader industrial applications. A comparative financial analysis of 120 MW utility-scale configurations shows that the PVT + ORC option yields a Levelized Cost of Energy of $44/MWh, significantly outperforming PV + CSP ($82.8/MWh) and PV + BESS ($132.3/MWh). In addition, the capital expenditure is reduced by over 50%, and the system requires 40–60% less land, offering a transformative solution for off-grid data centers, water desalination (producing up to 300,000 m³/day using MED), district cooling, and industrial process heat. The energy payback time is shortened to less than 4.5 years, with lifecycle CO₂ savings of up to 1.8 tons/MWh. Additionally, the integration with Organic Rankine Cycle (ORC) systems ensures 24/7 dispatchable power without reliance on batteries or molten salt. Positioned as a next-generation solar platform, the Hassabou system presents a climate-resilient, modular, and economical alternative to current hybrid solar technologies. This work advances the deployment readiness of integrated solar-thermal technologies aligned with national decarbonization strategies across MENA and Sub-Saharan Africa, addressing urgent needs for energy security, water access, and industrial decarbonization. Full article

Bacterial nanocellulose (BNC) composite films have emerged as promising candidates for sustainable building materials, yet their practical application in building-integrated photovoltaics (BIPV) facade systems is hindered by insufficient mechanical strength, poor environmental stability, and limited energy efficiency. Here, we developed bacterial nanocellulose/zinc oxide–phenolic resin (BNC/ZnO–PF) composite films with high-strength, stability, and energy efficiency for BIPV facade system through a simple strategy. Specifically, we first prepared BNC films, then in-situ grew ZnO nanoparticles on BNC films via ultrasound assistance, and finally hot-pressed the BNC/ZnO films with PF resin. The BNC/–PF composite films exhibit high mechanical strength (tensile strength of 93.8 MPa), exceptional sturdiness (wet strength of 92.3 MPa), and thermal properties, demonstrating their durability for long-term outdoor applications. Furthermore, the BNC/ZnO–PF composite films show high transparency (86.47%) and haze (82.02%) in the visible light range, enabling effective light propagation and scattering, as well as soft, uniform, and large-area light distribution. Meanwhile, a low thermal conductivity of 21.7 mW·m⁻¹·K⁻¹ can effectively impede the transfer of high outdoor temperatures into the room, significantly reducing the energy consumption demands of heating and cooling systems. Coupled with its ability to en-hance the photovoltaic conversion efficiency of solar cells by 12.9%, this material can serve as the core encapsulation layer for BIPV facades. While enabling build-ing-integrated photovoltaic power generation, through the synergistic effect of light management and thermal insulation, it is expected to reduce comprehensive building energy consumption, providing a new solution for building energy efficiency under carbon neutrality goals. Full article

The global energy landscape is transforming, driven by the urgent need to address climate change, reduce dependency on fossil fuels, and promote sustainable economic growth. Renewable energy sources (RESs) have emerged as a cornerstone of this transition, offering environmental benefits and significant potential to catalyze economic development. By harnessing inexhaustible natural resources, such as solar, wind, hydro, and biomass, renewable energy systems provide a pathway to achieving energy security, fostering innovation, and generating new economic opportunities. In this article, the economic effect on the RES sector development was examined. The authors defined the set from seven indicators: real GDP growth, unemployment rate, inflation rate, exports of goods and services, government debt, foreign direct investments, and labor cost index, which allowed them to evaluate the EU countries’ economic situation and rank the countries by economic stability level. The results, which were obtained using a multi-criteria evaluation method, show that the EU countries whose economies are the strongest according to the evaluated macroeconomic indicators are Luxembourg, Malta, Estonia, and Ireland. The countries with the lowest scores are Greece, Italy, and Spain. Seeking to evaluate the development level of the RES sector in all ranked EU countries, the analysis of RES sector development during the 2012–2022 period, using these RES indicators—share of renewable energy in gross final energy consumption by sector—in general, in transport, in electricity, and in heating and cooling, was carried out and, through a different multi-criteria method, the countries were ranked by RES development. After the analysis was carried out, it could be stated that the economic situation stability in the country does not directly affect the growth of the RES sector development, and the two rankings by different indicators are heavily uncorrelated. RES sector development can be affected by many other circumstances. RES development is still stagnating in some countries, despite macroeconomic stability, for several reasons: institutional and political barriers, differences in the availability of finance, infrastructure limitations, and technological and human resource shortages. Full article

Practical applications such as solar power energy systems, electronic cooling, and the convective drying of vented enclosures require continuous developments to enhance fluid and heat flow. Numerous studies have investigated the enhancement of heat transfer in L-formed vented cavities by inserting heat-generating components, filling the cavity with nanofluids, providing an inner rotating cylinder and a phase-change packed system, etc. Contemporary work has examined the thermal performance of L-shaped porous vented enclosures, which can be augmented by using metal foam, using nanofluids as a saturated fluid, and increasing the wall surface area by corrugating the cavity’s heating wall. These features are not discussed in published articles, and their exploration can be considered a novelty point in this work. In this study, a vented cavity was occupied by a copper metal foam with $PPI=10$ and saturated with a copper–water nanofluid. The cavity walls were well insulated except for the left wall, which was kept at a hot isothermal temperature and was either non-corrugated or corrugated with rectangular waves. The Darcy–Brinkman–Forchheimer model and local thermal non-equilibrium models were adopted in momentum and energy-governing equations and solved numerically by utilizing commercial software. The influences of various effective parameters, including the Reynolds number ($20\le Re\le 1000$), the nanoparticle volume fraction ($0\%\le \phi \le 20\%$), the inflow and outflow vent aspect ratios ($0.1\le D/H\le 0.4$), the rectangular wave corrugation number ($N=5$ and $N=10$), and the corrugation dimension ratio ($CR=1$ and $CR=0.5$) were determined. The results indicate that the flow field and heat transfer were affected mainly by variations in $Re$, $D/H$, and $\phi$ for a non-corrugated left wall; they were additionally influenced by $N$ and $CR$ when the wall was corrugated. The fluid- and solid-phase temperatures of the metal foam increased with an increase in $Re$ and $D/H$. The fluid-phase Nusselt number near the hot left sidewall increased with an increase in $\phi$ by $\left(25–60\right)\%$, while the solid-phase Nusselt number decreased by $\left(10–30\right)\%$, and these numbers rose by around $3.5$ times when the Reynolds number increased from $20$ to $1000$. For the corrugated hot wall, the Nusselt numbers of the two metal foam phases increased with an increase in $Re$ and decreased with an increase in $D/H$, $CR$, or $N$ by $10\%$, $19\%$, and $37\%$. The original aspect of this study is its use of a thermal, non-equilibrium, nanofluid-saturated metal foam in a corrugated L-shaped vented cavity. We aimed to investigate the thermal performance of this system in order to reinforce the viability of applying this material in thermal engineering systems. Full article

One of the most important applications of solar energy is electricity generation using photovoltaic (PV) panels. Yet, as the temperature of PV modules rises, both their efficiency and service life decline. A common approach to mitigate this issue is cooling with fins, a design that is now widely adopted. However, traditional fin-based cooling systems often fail to deliver adequate performance in hot regions with strong solar radiation. In particular, passive cooling alone shows limited effectiveness under conditions of high ambient temperatures and intense sunlight, such as those typical in Malaysia. To address this limitation, hybrid cooling strategies, especially those integrating both air and water, have emerged as promising solutions for enhancing PV performance. In this study, an experimental and economic investigations were carried out on a PV cooling system combining copper tubes and aluminium fins, tested under Malaysian climatic conditions. The economic feasibility was evaluated using the Simple Payback Period (SPP) method. An outdoor test was conducted over four consecutive days (10–13 June 2024), comparing a conventional PV module with one fitted with the hybrid cooling system (active and passive). The cooled module achieved noticeable surface temperature reductions of 2.56 °C, 2.15 °C, 2.08 °C, and 2.58 °C across the four days. The system also delivered a peak power gain of 66.85 W, corresponding to a 2.82% efficiency improvement. Economic analysis showed that the system’s payback period is 4.52 years, with the total energy value increasing by USD 477.88, representing about a 2.81% improvement compared to the reference panel. In summary, the hybrid cooling method demonstrates clear advantages in lowering panel temperature, enhancing electrical output, and ensuring favorable economic performance. Full article

From September 8th to 12th, 2024, the 19th SDEWES Conference on Sustainable Development of Energy, Water, and Environment Systems was successfully held in Rome. This event drew 700 researchers, scientists, and practitioners from 62 nations across six continents, with 570 participating in person and another 130 joining virtually. A total of seven papers were selected to be published in Energies, and the corresponding literature published in the most recent year is here reviewed. The main topics of the selected papers regard the adoption of district heating and cooling and their integration with renewable energies (such as geothermal or solar, the use of innovative bifacial PV panels, the use of biomass energy for the bio-synthetic natural gas production, the short-term electric load forecasting for industrial applications, and others. The reviewed papers show that several energy measures can be addressed to reach the decarbonization goals of 2050 and that the scientific community continues to find novel, sustainable, and efficient methods for the reduction in energy consumption and related CO₂ emissions. Full article

The world’s energy system faces major challenges due to transitions from fossil fuels to other alternatives. An important part of the transition is energy-efficient homes that partially produce their own electricity. This paper explores the energy interactions between heating, cooling, and electricity usage in a planned residential area in Sweden where a significant portion of the electricity is generated by solar PV systems. Conventional district heating and cooling systems and a low-temperature district heating system that uses return cascading technology were compared with heat pump systems. Electricity sharing in an energy community has a low impact on the calculated national energy efficiency metric. It is also shown that electrifying space heating with heat pumps improves the calculated energy efficiency metric, but heat pumps increase the peak power demand in the winter due to high heat demand and a lack of solar production. Using heat pumps for heating domestic hot water and compressor chillers for cooling offers a more balanced use/production of electricity since the electric cooling load is mostly met by local solar production, as shown by an increase in self-consumption of 8% and stable self-sufficiency. There is, however, a time mismatch between production and the peak electricity demand, which could be addressed by using energy storage systems. Full article

Natural cooling and ventilation have been fundamental principles in vernacular architecture for millennia, shaping sustainable building practices across diverse climatic regions. This paper examines the historical evolution, technological advancements, environmental benefits, and prospects of passive cooling strategies, with a particular focus on wind catchers. Originating in Mesopotamian, Egyptian, Caucasia, and Iranian architectural traditions, these structures have adapted over centuries to maximize air circulation, thermal regulation, and humidity control, ensuring comfortable indoor environments without reliance on mechanical ventilation. This study analyzes traditional wind catcher designs, highlighting their geometric configurations, airflow optimization, and integration with architectural elements such as courtyards and solar chimneys. Through a comparative assessment, this paper contrasts passive cooling systems with modern HVAC technologies, emphasizing their energy neutrality, low-carbon footprint, and long-term sustainability benefits. A SWOT analysis evaluates their strengths, limitations, opportunities for technological integration, and challenges posed by urbanization and regulatory constraints. This study adopts a comparative analytical method, integrating a literature-based approach with qualitative assessments and a SWOT analysis framework to evaluate passive cooling strategies against modern HVAC systems. Methodologically, the research combines historical review, typological classification, and sustainability-driven performance comparisons to derive actionable insights for climate-responsive design. The research is grounded in a comparative assessment of traditional and modern cooling strategies, supported by typological analysis and evaluative frameworks. Looking toward the future, the research explores hybrid adaptations incorporating solar energy, AI-driven airflow control, and retrofitting strategies for smart cities, reinforcing the enduring relevance of vernacular cooling techniques in contemporary architecture. By bridging historical knowledge with innovative solutions, this paper contributes to ongoing discussions on climate-responsive urban planning and sustainable architectural development. Full article

In order to explore the increase in the environmental benefits of solar ground source heat pump (SGSHP) systems, this study assesses the environmental benefits of SGSHPs through a comprehensive sustainability evaluation, integrating life cycle assessment, carbon emission analysis, and emergy analysis based on a real project in Tianjin (39.13° N, 117.2° E). By comparing an SGSHP with the conventional GSHP system, improvements in sustainability performance are quantified. The analysis reveals that the SGSHP system has a full-cycle EI16 of 1.88 × 10³, which is 15% higher than the GSHP value of 1.63 × 10³. The SGSHP demonstrates a significant advantage in terms of carbon emissions at all stages, with an overall carbon emission of 31,671 kgCO₂-eq, which is a reduction of about 9.4% compared to the 34,955 kgCO₂-eq of the conventional GSHP system. The emergy conversion rate of SGSHP is 3.58 × 10³, which is 16.23% higher than that of GSHP. This shows that the system with the addition of solar energy is able to convert raw energy into useful heat or cooling energy more efficiently, reducing emergy wastage and making it operate more efficiently, with emergy saving and environmental advantages. The SGSHP system has an ESI value of 1.12, indicating that it is in a developmental or intermediate stage, with significant potential for sustainable economic contributions. In contrast, the GSHP system, with an ESI value of 0.98, demonstrates that it is not sustainable over the long term. By using a comprehensive environmental assessment framework and comparative data analysis, this study aims to better understand the SGSHP system’s performance in energy use, carbon emissions, and ecological impact, providing a scientific foundation for its wider adoption. Full article

Urbanization in China and the proliferation of high-rise office buildings have led to increased demand for daylighting and thermal comfort. These requirements often result in reliance on active systems, including heating, cooling, and artificial lighting, which increase energy consumption. Existing studies have often focused on individual cases or room-scale models, which makes it difficult to generalize findings to the design of various high-rise office building types. Therefore, in this study, parametric prototype building models for high-rise office buildings were developed based on surveys of completed and under-construction projects. These surveys reflected actual design practices and were used to support systematic performance evaluation and typology-level optimization. Building performance was simulated using Grasshopper and Honeybee to generate large-scale datasets, and stacking ensemble learning models were used as surrogate predictors for energy use, daylighting, and thermal comfort. Multi-objective optimization was conducted using the non-dominated sorting genetic algorithm III (NSGA-III), followed by strategy formulation. The results revealed the following: (1) the proposed prototype model establishes clear parameter ranges for geometry, envelope design, and thermal performance, offering reusable models and data; (2) the stacking ensemble model outperforms individual models, improving the coefficient of determination (R²) by 0.5–16.1%, with mean squared error (MSE) reductions of 4.4–70.6%, and mean absolute error (MAE) reductions of 2.8–45.8%; (3) space length, aspect ratio, usable area ratio, window U-value, and solar heat gain coefficient (SHGC) were identified as primary performance drivers; and (4) optimized solutions reduced energy use by 3.79–11.81% and enhanced daylighting comfort by 40.16–50.32% while maintaining thermal comfort. The proposed framework provides localized, data-driven guidance for early-stage performance optimization in high-rise office building design. Full article

The energy requirements for conditioning spaces have been increasing primarily due to population growth and climate change. This paper shows a comparison between an adsorption (ADC) and absorption cooling (ABC) systems to keep a building below the 25 °C set-point in dynamic conditions, utilizing a latent heat storage tank with MgCl₂·6H₂O and erythritol, and employing evacuated tube and parabolic trough collectors. The storage tank geometry is a plate heat exchanger. An auxiliary system was incorporated to control the temperature range of the solar cooling systems. The results showed that the coefficient of performance was kept around 0.40–0.60 and 0.70 for adsorption and absorption cooling, respectively. The latent heat storage tank with erythritol captured more solar energy than MgCl₂·6H₂O. A maximum solar fraction of 0.96 was obtained with MgCl₂·6H₂O, a thickness of 0.15 m, 20 m² of parabolic trough collector area, and absorption cooling, while the energy supply was fully satisfied with a solar collector with erythritol, a thickness of 0.1 m, 13 m² of parabolic trough area, and absorption cooling. In general, erythritol obtained better results of solar collector fractions than MCHH; however, it has less thermal stability than MgCl₂·6H₂O, and the cost is higher. Full article

This study developed a novel folding light shelf system that integrates reflectors, photovoltaic (PV) modules, and adaptive louvers that adjust based on solar altitude, aiming to improve daylight distribution, minimize glare, and reduce energy consumption in office buildings. The research employed an advanced optimization approach, utilizing Non-dominated Sorting Genetic Algorithm III (NSGA-III) and Latin Hypercube Sampling, a highly effective method suitable for managing complex multi-objective scenarios involving numerous variables, to efficiently identify high-performance configurations with increased precision. Key design variables across all three components of the system included angle, width, distance, and the number of folds in the light shelf, along with the number of louvers. The proposed method successfully integrates PV technology into light shelves without compromising their functionality, enabling both daylight control and energy generation. The optimization results demonstrate that the system achieved up to a 15% improvement in useful daylight illuminance (UDI) and a 16% reduction in cooling energy consumption. Furthermore, the PV modules generated 509.5 kWh/year, ensuring improved efficiency and sustainability in building performance. Full article