Sustainable Energy Technologies and Assessments最新文献

Vehicle emissions can rise due to traffic conflicts and aggressive driving behaviors, such as frequent acceleration and deceleration. This issue is particularly pronounced at non-signalized intersections with a high proportion of non-motorized vehicles. In this study, we propose a framework that integrates a microscopic vehicle emission model with trajectory data. By utilizing trajectory data collected from a non-signalized intersection in Shanghai, we analyzed vehicle emissions linked to driving behaviors and traffic conflicts. Our findings reveal that pre-braking at the entrance of non-signalized intersections can significantly reduce vehicle emissions, lowering them by nearly 80 % for straight maneuvers. However, this reduction is less substantial for turning maneuvers. Additionally, conflicts involving more than two types of targets lead to a significant increase in vehicle emissions. On average, stop-and-go emissions are 1.13 % higher than those resulting from traffic conflicts. Interestingly, when non-motorized vehicles constitute more than 80 % of the traffic volume, stop-and-go emissions fall below those generated by traffic conflicts. The results of this study provide valuable insights for optimizing eco-driving strategies and advancing towards a low-carbon transportation system.

To effectively improve the quality of dried Auricularia auricula and reduce drying energy consumption, based on a designed heat pump experimental device, the impacts of drying temperature as a critical factor, on the drying characteristics of Auricularia auricula and the performance of the heat pump system as well were investigated experimentally. The results show that, within the drying temperature range of 40–65 °C, as the drying temperature increases, the decrease in the moisture ratio (MR) becomes more pronounced. Drying time decreases from 495 min to 255 min, with an average drying rate (DR) increasing by 93.8 %. The average coefficient of performance of the system (COP_sys) decreases by 14.9 %, the average specific moisture extraction rate (SMER) and the rehydration ratio (R_f) both initially increases and then decreases. At a drying temperature of 55 °C, the average SMER reaches its maximum value at 0.74 kg/kWh, indicating the optimal dehumidification performance for the system. Meanwhile, at a drying temperature of 50 °C, R_f for Auricularia auricula reaches its maximum value at 14.16, signifying the optimal quality of Auricularia auricula. Compared to hot air drying, the heat pump drying (HPD) system demonstrates lower energy consumption and superior economy, while also yielding higher-quality Auricularia auricula. The findings can provide valuable insights into the employment of heat pump drying system in the drying process of Auricularia auricula.

High-alkali coal is abundant and can cope with the current energy supply and demand gap. However, the sustainable utilization of high-alkali coals is limited by their abundance of alkali metal species, which can lead to severe ash-related problems such as ash accumulation, slagging, and corrosion during its combustion in boilers. To explore the clean and sustainable utilization of high-alkali coal in coal-fired boilers, it is crucial to study the release and transformation behavior of alkali metals in the combustion process. First, this paper reviews the alkali metal measurement methods for high alkali-coal combustion processes. Further, the migration properties of alkali metals are summarized in terms of coal composition, temperature, and combustion atmosphere. Current co-combustion technologies for high-alkali coals with additives/other fuels and their effects on alkali metals are summarized and evaluated. Finally, the authors propose suggestions for the development of high-alkali coal combustion technologies based on current research on the behavior of alkali metals.

PV arrays are susceptible to various types of failures such as partial shading that can negatively affect their performance and efficiency. Studying the impact of these circumstances in the performance of the PV array is key for the development of more efficient PV systems. In this study, the definition of the expected value of power (EVP) that a PV array can produce under a random failure scenario is revised and improved. An algorithm to compute EVP that minimizes the number of simulations is developed and tested in three different PV arrays. Results show a 96.6% reduction on average of the number of simulations needed to compute the EVP for PV arrays made up of 9 modules. The model is validated through an experiment that reproduces the random fault scenario and determines the mean power produced by the PV arrays. For all three experiments, the computed EVP fits the experimental data with $R^2>0.995$.

The fundamental reason developed countries can cater to their lifestyle demands is their energy security, employment creation, and containment of greenhouse gases. Concerning the rising global temperatures due to the increasing levels of ozone depletion, sustainable energy adoption into mainstream energy generation has become predominantly accepted. Various governments and agencies have promoted renewable energy sources with desirable policies and financial investments in these projects. However, the efforts have not met the requirements to keep the temperatures below 1.5 degrees or a maximum of 2 degrees. The COVID-19 pandemic has caused a major decline in Nepal’s economy, which is primarily dependent on agriculture and remittances. Around 2% GDP growth is expected in the nation, which will affect approximately 18% of the populace living in poverty. As a result, Nepal’s conditional Nationally Determined Contributions (NDC) reflect emissions levels between 69 and 76 MtCO₂e, with a reduction goal of 1.9 to 5.6 MtCO₂e by 2030. Nepal’s total carbon dioxide emissions will rise in 2021 despite the country’s meager 0.027% contribution to world emissions. This would lead to the implementation of the Green, Resilient and Inclusive Development (GRID) approach, which aims to promote sustainable green growth and resilience. Singapore’s mitigation efforts and energy generation prospects in different sectors, such as transportation, industry, building, biogas, wind, nuclear, solar, and waste to energy. This paper will be a comparative study of the energy markets of the Federal Democratic Republic of Nepal & the Republic of Singapore. It will also reveal the relationship between policy scenarios and greenhouse gas emissions. It will enlist the current challenges of the growth of renewable energy markets and explore prospective economically viable energy production methods. In conclusion, it will also predict the energy mix for the agenda years of 2035 and 2050, thereby creating an economically reliable roadmap for energy generation for both countries to have a sustainable future by studying the varying socio-economic populations in this study.

The widespread use of fossil fuels in Pakistan has seriously challenged society and the environment. Transitioning to electric fuels such as hydrogen can not only help reduce air pollution but also reduce dependence on fossil fuels and enhance Pakistan’s economic sustainability. Recent studies show a lack of comprehensive investigation of renewable hydrogen for providing an informative roadmap to energy policymakers in Pakistan. This paper deals with discovering the renewable electricity potential and capacity assessment of hydrogen production by electrolysis in 62 stations in Pakistan using ArcGIS and HOMER software. The techno-economic feasibility study indicates that the lowest levelized cost of energy (LCOE) for solar electricity is $0.189/kWh (Quetta), while for wind-generated electricity is $0.3/kWh (Peshawar). The results also indicate that the annual energy production of 143.5 MWh and 109.7 MWh from solar and wind energy, respectively. Moreover, the generated electricity can be used for water electrolysis to produce around 2.7 and 1.5 tons/year of hydrogen by solar and wind energy, respectively. According to the results, Mardan and Peshawar are the most suitable stations for renewable hydrogen production, while Islamabad is the least appropriate.

This research raises the possibility for households in energy poverty to participate in shared photovoltaic systems in renewable energy communities (REC) to reduce their energy costs, with investment costs covered by public institutions. It begins by evaluating the current solution for vulnerable households, which relies on public subsidies to lower energy costs without addressing root causes or improving environmental impacts. The study compares traditional subsidies with REC participation for vulnerable households. By simulating a REC composed of such households, the results indicate that REC participation is more cost-effective for public institutions than energy subsidies. At the economically optimal size of 31 kWp, the cost of subsidies decreases by 58,000 €, a 50% reduction, with household savings increasing by 6%. At 58 kWp, the need for additional support checks is eliminated, increasing household savings by 65% but with a lower NPV of 22,500 €. The largest viable system, 75 kWp, increases average household savings by 82%. This approach also leads to a net reduction in GHG emissions, engaging previously excluded households in the energy transition.

Novel design methodology for low-cost solar simulator for testing standard-sized solar collectors at various incidence angles is introduced. Ray tracing and theoretical approach are used to define development stages. Simulator dimensions are defined in the initial stage. Light source selection and ray tracing analysis are shown for prototype system combining visible spectrum LED reflectors and infrared quartz heaters. Configurations of light sources are assessed using ray tracing to achieve uniform test area irradiation. Prototype assembly and testing are presented and JIS C 8904-9 compliance standard characteristics are determined. Spectral match to solar spectrum results in Class C. Spatial non-uniformity of irradiance is 7.8 % and classified as B. Short-term and long-term temporal instability yields values of 0.39 % and 0.63 %, respectively. Temporal instability achieved Class A. The overall classification of the simulator is CBA. Total simulator power draw is 9.07 kW with a conversion efficiency of 33.6 %. Using the developed prototype, stagnation temperature measurements of polymer collector prototype was conducted using solar simulator and outdoor setup. Prototype collector stagnation temperature without any overheating protection was 95 °C in the simulator and 90 °C in the outdoor test setup. With overheating protection it reached 73 °C in the simulator and 70 °C in the outdoor setup.

As amphibious vehicles, hovercrafts glide over nearly frictionless surfaces thanks to a unique lift fan design that counteracts gravitational forces. However, this design leads to high energy consumption. Typically, hovercrafts operate their lift fan at maximum capacity or adjust it manually. This paper introduces an adaptive control method to mitigate a significant drawback of hovercrafts, which is excessive energy consumption stemming from their unique lift fan design. It discusses a methodology for identifying the most energy-efficient design, based on computational fluid dynamics analysis. Hovering and propulsion principles are addressed in detail to demonstrate the forces acting on the hovercraft and the motor selection process. This study’s pioneering integration of adaptive and hysteresis controls for the lift fan represents a significant advancement in hovercraft energy management, offering a novel approach that markedly enhances operational efficiency and environmental sustainability. The paper proposes and evaluates various drive cycles to assess the control method’s effectiveness and environmental impact. The results show that this approach can reduce energy use and, as a result, carbon emissions by up to 48.3 %.

Passive strategies involving greenery significantly increase energy performance in buildings and comfortable microclimate conditions. However, few studies model and simulate their effect on buildings’ energy performance. Thus, this work assesses modelling approaches for conducting building performance simulations where detached vertical green trellises (DVGT) are included. The DVGT characteristics are modelled by: (i) large solid component blocks and (ii) small opaque solid component blocks to form a grid. A building with glazed façades is evaluated through dynamic simulation under the tropical climate of Panama City, using DesignBuilder. Parametric analysis is performed to study the impact of the trellis configuration on the performance in reducing the annual cooling, lighting, and total electricity consumption. A cost-effective evaluation is also conducted based on the net present value for each trellis configuration. Results showed strong agreement with previous studies reporting significant cooling needs reduction while increasing lighting needs and promising return periods. This concludes that the correct optical and radiative properties of the vegetation layer that are wanted to be modelled in a detached vertical trellis are crucial.