Sustainable Energy Technologies and Assessments最新文献

Structure supercapacitors (SSC) have aroused tremendous interest in building energy storage due to their dual function of electrochemical-mechanical properties. As well known, the low energy storage capacity limits their development. To enhance the energy density of SSC, lots of high-performance structural electrodes were developed. Herein, Mg and S elements were used to regulate the microstructure of the binary metal hydroxide, which could improve the electrode’s electrochemical performance. As we expected, rGO/N₁C₃Mg-S₄′ electrode exhibits high areal capacitance (10.20F/cm²), which boosts the electrochemical capacitance of SSC. Our device based on rGO/N₁C₃Mg-S₄′ electrode exhibits a high areal capacitance (179.21 mF/cm²) and a high energy density (56 μWh/cm²) at 3 mA/cm². More importantly, the electrochemical performance of our device doesn’t change obviously under a certain amount of pressure, demonstrating its good practical application potential in buildings.

In the effort to conserve energy and reduce emissions, waste heat recovery for power generation offers a significant advantage by enabling energy recycling. The turbo-expander, a critical component within expansion power generation systems, plays a pivotal role. However, flow during various operation can generate vibrations that negatively affect operational efficiency and trigger safety hazards. Therefore, studying the flow-induced vibration of the turbo-expander is of significant value. We apply computational fluid dynamics (CFD) and transient structural mechanics to examine the flow-induced vibration characteristics of the turbo-expander influenced by stator-rotor interaction using a two-way fluid structure interaction (FSI) strategy. The flow field modeling and calculation approach discussed here is validated through actual operating data from a prototype. Subsequent stages involve coupling the steady-state flow field with the structural field and performing pre-stress modal analysis on the impeller. In the end, we integrate flow-induced excitation from flow field calculations with the transient structural field to calculate the impeller’s flow-induced vibration at the expansion end of the turbo-expander. Our analysis reveals that guide vane frequency (3267 Hz), its harmonic frequencies, and pre-stress modal frequency (1465 Hz) prominently manifest in pressure pulsation and the dynamic response of the turbo-expander impeller under the influence of stator-rotor interaction.

Lateral sliding triboelectric nanogenerators LS-TENGs promise to combine low cost and high-efficiency mechanical energy harvesting at low frequency with the advantages of light weight and simple device architecture. To date, device power generation optimization has only been addressed on the framework of the optimal load resistance through the maximum power transfer theorem (MPTT). However, MPTT is a concept to optimize the power transferred from TENGs to loads, but not for optimizing the power generated by the TENG itself. In response, this work reports a concept that resembles the population growth model of species for designing enhanced performance LS-TENGs with optimal charge-generating rate. In this way, devices designed under the proposed concept possess a significantly enhanced optimal charge and power generation rate up to 3-fold and 8-fold respectively superior to those found for conventional rectangular TENGs with similar capacity, which allows us power up sustainably for hours low power consumption devices with a few minutes of mechanical energy harvesting. Thereby, this model aids in the development of enhanced performance LS-TENGs capable of collecting mechanical vibrations and optimally converting them into electrical energy by breaking the limits set by the MPTT, as well as opening a route towards batteryless power autonomy.

Cold chain logistics involves all aspects of food storage, transport, and sales. This study focuses on innovating cold storage disinfection within this context. Regular disinfection reduces microorganism growth, improves food quality, and ensures safety. Traditional methods lack automation, accurate monitoring, and responsive control. Conventional sensors are unsuitable for curved bottles and need frequent power changes. This paper proposes a light energy harvested flexible wireless sensing for disinfection sterilization in food storage (FLWDS). FLWDS comprises five parts: light energy harvesting and power supply node (LEPN), sensing node, control node, monitoring node, and host computer. A predictive control model improves response speed and accuracy. Bluetooth technology ensures real-time communication between nodes. FLWDS collects light energy inside the cold store as a supplementary energy source and can be used in curved structures with a response time of less than 1 s. The maximum communication distance is 40 m. The flexible level sensing system can be designed according to the induction pad’s length, with a measurement accuracy of 0.3 mm, sampling every 4.8 ms, and a resolution of 0.2 mm. FLWDS provides self-powered flexible wireless sensing, ensuring accurate liquid level measurement, improved food quality, reduced pollution, and increased sustainability.

High global warming potential gases (“high GWP”) are the fastest growing sector of greenhouse gas emissions in the world and in California and are primarily used as refrigerant gases in refrigeration and cooling equipment. Hydrofluorocarbons (HFCs) refrigerants are the dominant type of high GWP gases with GWP values thousands of times larger than CO₂ on a 100-year timescale. Refrigerant-grade propane (“R290”) has a very low GWP (GWP = 3.3) with good thermodynamic properties and good cooling equipment performance but the flammability of any leaked refrigerant makes equipment design, handling, and maintenance critical factors to manage. This paper focuses on the potential climate benefits and costs of transitioning to R290 refrigerant in small room air conditioning (AC) units, specifically window AC, packaged terminal AC/heat pumps (PTAC/PTHP), and mini-split heat pumps. Overall climate impact for a transition to all three types of air conditioning units in the 2022–2051 timeframe is found to be from 15 to 64 million metric tons of greenhouse gas (GHG) savings in California with a cost of saved CO₂eq that ranges from $14.50 per ton of CO₂eq saved to −$50.30 per ton of CO₂eq saved (net savings) depending on whether the baseline refrigerant is R32 or R410A and depending on the relative energy efficiency for R290 units compared to baseline units.

Piggy-backed anchors present a promising solution to address the limitations of single Drag Embedment Anchors (DEAs). A series of centrifugal model tests were performed on the installation of piggy-backed anchors with varying spacings and attachment points in saturated sand using a magnetometer system. The experimental results validated the proposed theoretical prediction model, which can identify the trajectory, capacity, orientation, and soil failure wedge slip surface. Key findings include: (1). the embedment depth of the second anchor in piggy-backed anchors is significantly greater than that of a single anchor, resulting in the total capacity of piggy-backed anchors exceeding twice that of a single anchor at appropriate spacing; (2). investigating spacing effects shows that capacities are less than twice that of the single anchors when spacing is less than 1L_f due to overlapping failure soil wedges; optimal spacing was found to be 2L_f to 3L_f; (3). piggy-backed anchors with attachment points at the back of fluke exhibit better embedment performance and capacity stability compared to those with attachment points at the padeye. Finally, the prediction model explored the capacity performance of piggy-backed anchors at different loading angles at the final embedment depth, revealing a two-stage failure process compared to single drag anchors.

This study evaluates an innovative domestic indirect solar dryer (ISD) for drying grapes (Vitis Vinifera L.), focusing on energy, exergy, economic, and sustainability performance. Two trials with crop loads of 15% (Trial-1) and 33% (Trial-2) were conducted. Trial-2 exhibited higher energy efficiencies in the solar collector (SC) and drying chamber (DC) compared to Trial-1, with efficiencies of 61.4% and 58.5% for SC, and a 13% increase in DC efficiency. The daily average exergy efficiencies for SC and DC ranged from 11%–13% and 54%–58%, respectively. Trial-2 also showed a 113% higher life cycle savings, a 54.4% decrease in payback period, and a 23% lower waste exergy ratio compared to Trial-1. Pre-treatment of grapes resulted in superior dried product quality. The study highlights the ISD’s potential as an economically and environmentally sustainable solution for small-scale agricultural ventures, providing insights for renewable energy sectors

Fuel cells are among the best options for producing electrical energy due to their advantages, such as high efficiency, wide range of production, environmental adaptability, and no noise pollution. One of the most valuable applications of fuel cells is their use in combination with renewable systems to respond to one of the main weaknesses of these systems, namely the inability to produce electricity continuously and meet on-peak electricity demand. The surplus of electricity generation is converted to Hydrogen and used by the Fuel Cell to generate electricity on-peak gird. The total energy efficiency of these systems has reached 71.3%. In addition to electricity, heat and cooling load can be supplied in multiple hybrid systems, and energy wasted can be used to improve efficiency. The hybrid renewable energy systems could facilitate a new generation of decentralized energy, ease of life in isolated areas, high reliability, the elimination of CO₂ emissions, and a step towards sustainable development.

This paper presents an assessment of the energy harvesting potential from wave-induced motions when producing electricity by linear generators installed on ships. The study estimates an upper maximum energy extraction potential by not considering the electro-mechanical coupling; neither is mechanical and electrical dissipation considered. The analysis of the harvested energy is made using simulated data in a case study investigating three different ships (by size). Specifically, the case study reveals that, in moderate to mildly severe sea states, the power harvested from the environment using linear generators may reach values around 1–2 kW/tons of seismic mass. Thus, it is unrealistic to imagine ship designs where linear generators are thought to provide a ship’s necessary propulsion power but, on the other hand, they may serve to supplement the main engine for auxiliary power generation.

New researchers in Performance-Enhancing Thermal Management Strategies (PETS) for photovoltaic (PV) technology struggle with scattered data, hindering their efforts. This research gap is addressed by extracting key information from 1,474 documents in the Web of Science and Scopus databases and conducting a thorough data analysis. The findings reveal three phases of the trend inception, gradual growth period, tech-advanced period, and rapid progress. The bibliometric results show a 24.98% growth rate, 25.01 citations per document, 2,577 researchers involved, and 275 production sources. China, India, and other Asian countries are the main collaborators in this field, emphasizing the impact of hot climate regions in Asia on the choice of PETS methods. The main researchers collaborating with PETS are Sopian. K, Jie Ji, and Pie Gang. Furthermore, a review of keywords suggests that most experimental and numerical studies have prioritized temporal and performance outcomes, often neglecting long-term practical viability considerations. Future research should prioritize the 4E (Energy, Exergy, Economic and Environmental) analysis approach to address this gap effectively. Advancements in evaporative cooling and PVT technology have evolved in offshore solar plants, PV with heat pumps, and building-integrated PV (BIPV). This analysis sets the stage for future PV advancements in PETS technology.