Energy Utilization Efficiency Research Articles

Topology optimization design for voltage enhancement in variable structure double-layer flexible thermoelectric devices

Flexible thermoelectric devices possess the capability to generate electricity by harnessing temperature differences, rendering them highly promising for applications in wearable devices and powering the Internet of Things. This paper introduces a topology optimization design approach for double-layer thin-film flexible thermoelectric devices with the aim of enhancing the device's output voltage and improving the efficiency of green energy utilization. The design process took into consideration the coupled effects of mechanical, electrical, and thermal aspects. It not only optimized the force transmission paths of the variable structure device but also accounted for heat dissipation and circuit topology configuration. The study employed a field function model to concurrently optimize the structure of both the substrate and thermoelectric materials in an integrated design, with the primary objective being the maximization of output voltage. The efficacy of this methodology was confirmed through a series of numerical simulations and experiments conducted under various load and operational conditions. The optimized flexible thermoelectric devices exhibited an output voltage increase of more than threefold when compared to flat devices.

Quasi-homogeneous photoelectrochemical organic transformations for tunable products and 100% conversion ratio

Photoelectrochemical (PEC) organic transformation at the anode coupled with cathodic H2 generation is a potentially rewarding strategy for efficient solar energy utilization. Nevertheless, achieving the full conversion of organic substrates with exceptional product selectivity remains a formidable hurdle in the context of heterogeneous catalysis at the solid/liquid interface. Here, we put forward a quasi-homogeneous catalysis concept by using the reactive oxygen species (ROS), such as ·OH, H2O2 and SO4•−, as a charge transfer mediator instead of direct heterogeneous catalysis at the solid/liquid interface. In the context of glycerol oxidation, all ROS exhibited a preference for first-order reaction kinetics. These ROS, however, showcased distinct oxidation mechanisms, offering a range of advantages such as ∼ 100 % conversion ratios and the flexibility to tune the resulting products. Glycerol oxidative formic acid with Faradaic efficiency (FE) of 81.2 % was realized by the H2O2 and ·OH, while SO4•− was preferably for glycerol conversion to C3 products like glyceraldehyde and dihydroxyacetone with a total FE of about 80 %. Strikingly, the oxidative coupling of methane to ethanol was successfully achieved in our quasi-homogeneous system, yielding a remarkable production rate of 12.27 μmol h−1 and an impressive selectivity of 92.7 %. This study is anticipated to pave the way for novel approaches in steering solar-driven organic conversions by manipulating ROS to attain desired products and conversion ratios.

Allosteric Regulation of Pyruvate Kinase Enables Efficient and Robust Gluconeogenesis by Preventing Metabolic Conflicts and Carbon Overflow.

Glycolysis and gluconeogenesis are reciprocal metabolic pathways that utilize different carbon sources. Pyruvate kinase catalyzes the irreversible final step of glycolysis, yet the physiological function of its regulation is poorly understood. Through metabolomics and enzyme kinetics studies, we discovered that pyruvate kinase activity is inhibited during gluconeogenesis in the soil bacterium Bacillus subtilis . This regulation involves an extra C-terminal domain (ECTD) of pyruvate kinase, which is essential for autoinhibition and regulation by metabolic effectors. Introducing a pyruvate kinase mutant lacking the ECTD into B. subtilis resulted in defects specifically under gluconeogenic conditions, including inefficient carbon utilization, slower growth, and decreased resistance to the herbicide glyphosate. These defects are not caused by the phosphoenolpyruvate-pyruvate-oxaloacetate futile cycle. Instead, we identified two significant metabolic consequences of pyruvate kinase dysregulation during gluconeogenesis: increased carbon overflow into the medium and failure to expand glycolytic intermediates such as phosphoenolpyruvate (PEP). In silico analysis revealed that in wild-type cells, an expanded PEP pool enabled by pyruvate kinase regulation is critical for the thermodynamic feasibility of gluconeogenesis. Our findings underscore the importance of allosteric regulation during gluconeogenesis in coordinating metabolic flux, efficient energy utilization, and antimicrobial resistance.

Indoor space thermal cycle design and animation 3D modeling based on digital light processing technology

With the continuous development of architectural design concepts, the thermal cycle optimization of interior space has become an important topic to improve energy efficiency and comfort. The introduction of digital light processing (DLP) technology provides new possibilities for 3D modeling and thermal cycle analysis. This study uses digital light processing technology to design and optimize the thermal cycle of indoor space, and explores its application in real-time animation 3D modeling to provide a more intuitive visual display. DLP technology is used to build a three-dimensional model of interior space, and heat flow analysis software is combined to simulate the thermal cycle of different design schemes. The dynamic simulation method was used to analyze the change of heat circulation in the exhibition room and its influence on the indoor environment. The results show that the indoor thermal cycle optimized by DLP technology can effectively improve the heat distribution uniformity and energy efficiency utilization, and the simulation results show that the improved scheme has significant advantages in thermal comfort. This study proves the feasibility and effectiveness of digital light processing technology in indoor space thermal cycle design, and provides a new idea for future architectural design and thermal cycle management.

Damage behavior of the surrounding medium caused by different blast-induced dynamic and static loadings

The combination of the dynamic action of explosion stress wave and the static action of explosion gas expansion is what primarily drives rock-breaking blasting, and their different intensities lead to different blasting effects. Therefore, experiments were conducted to explore the damage behaviour of the surrounding medium caused by different blast-induced dynamic and static loadings using digital laser Schlieren and digital laser dynamic caustic systems. The results were as follows: In the air medium, when the explosives detonated, TATP (triacetone triperoxide) had the strongest quasi-static effect, and the highest velocity explosion shock wave and products compared with those of NHN (nickel hydrazine nitrate) and DDNP (diazodinitrophenol). Part of the TATP explosion product was ahead of the shock wave front, whereas for NHN and DDNP, their explosion products were behind the propagation of the shock wave front. The highest pressure peak of TATP was the result of the combined action of the shock wave and explosion product impacting the sensor. In the solid medium, NHN, the explosive with the strongest dynamic load, had the strongest stress wave and highest stress intensity factor peak of the main crack. The velocity reached the peak value at the early stage of propagation, and the dynamic action had a dominant effect on the cracking of the crack; the stronger the dynamic action, the higher the crack initiation energy. The stress intensity factor and propagation rate of the main crack of TATP with the strongest quasi-static effect decreased slower than those of the other explosives; therefore, the main crack propagation time and length were the longest. After cracking, the quasi-static effect dominated the process of crack propagation, where the stronger the quasi-static effect, the longer duration of the driving force of crack propagation. The research results provide a basis for customising explosives for different functions in practical engineering and realising the fine and efficient utilisation of explosion energy.

Simulation of low energy building thermal energy cycle in IoT smart city planning based on environmental sensors and deep learning

With the intensification of global climate change, the reduction of building energy consumption has become an important goal of smart city development. By optimizing the thermal energy circulation system, low energy buildings can not only reduce energy consumption, but also improve living comfort. In recent years, with the help of environmental sensors and deep learning technology, the intelligent management of building heat energy cycle has become a research hotspot. The research constructs an intelligent thermal energy circulation system that integrates multiple environmental sensors for real-time monitoring of indoor and outdoor temperature, humidity and other key environmental parameters. A deep learning algorithm is used to analyze the collected data to optimize the control strategy of the thermal energy cycle. Through simulation, the energy efficiency performance of the scheme under different climatic conditions and building types was evaluated. The experimental results show that the control strategy based on environmental sensors and deep learning can significantly improve the thermal energy utilization efficiency of low-energy buildings, and the average energy consumption is greatly reduced compared with the traditional management mode. The system shows good adaptability and stability under different climate conditions. Therefore, the application of environmental sensors and deep learning technology in the thermal energy cycle of low-energy buildings can effectively promote the energy efficiency management of smart cities.

Mechanism of the rapid generation of superheated and saturated steam using a water-containing porous material

Superheated steam (SHS) is employed in various fields for everyday activities and industrial production, e.g., drying, cleaning, and reaction engineering. Although a facile method for realizing rapid SHS and saturated steam generation from water-containing porous materials has been proposed, with a second order start-up/cut-off response time and high energy utilization efficiency, the mechanism of this rapid SHS generation has not been clarified despite the proposition of a two-step process, including heating-based evaporation beneath the wire heater and reheating in the flow path. In this study, further experiments were conducted to separately consider both heating processes. The steam temperature directly beneath the wire heater correlated well with the film temperature, which is equal to the average temperature of the wire heater and the saturation temperature of the surface of the porous material. The measurement results of the temperature distribution inside the porous material block as well as the results of the electrical resistance directly beneath the wire heater revealed that no dry-out area was formed directly beneath the wire heater during SHS generation. Further, the three-dimensional laser scanning results revealed significant roughness on the surface of the porous material. The narrow gap, which was formed between the wire heater and the surface of the porous material, was critical to SHS generation, and the detailed mechanism was presented.

Water-land-energy efficiency and nexus within global agricultural trade during 1995–2019

Agricultural product demand driven by population and economic growth poses challenges to water, land, and energy utilization, and this increasing local demand is largely met through trade. However, the efficiency and nexus pattern of the water, land, and energy embodied in agricultural trade are not well understood. This study uses the multi-regional input–output framework to analyze agricultural water, land, and energy utilization efficiency of resource footprints per unit economic output as well as their transfer and nexus pattern in global agricultural trade for 1995–2019. The results show that many international agricultural trade paths are inefficient in the water, land, and energy resource use because the agricultural products in these paths are exported from relatively low- to high-efficiency economies/regions. However, these inefficient transfer paths show an increasing trend over the study period. Regarding the water-land-energy nexus, conflicts are prevalent in land-energy and water-energy couplings. Most trade paths are conducted to alleviate the pressure on a specific resource, inadvertently increasing the pressure on other resources. Although agricultural trade is important for meeting global food demands, it is not consistently beneficial to the local environment when considering agricultural resources use efficiency. This study is expected to improve our understanding of agricultural trade impacts to the agricultural resources and support the sustainable development of global agriculture.

The effects of green finance on pollution and carbon reduction: Evidence from China’s industrial firms

Reducing pollution and carbon emissions is important but requires a large amount of capital. Green finance is becoming an important market-based instrument. Few literatures have focused on the direct impact of green finance on corporate environmental performance. This study investigates the effects of green finance on air pollution and carbon reduction in China’s industrial firms from 2008 to 2015. Results show that green finance promotes CO2 and air pollution reduction. Moreover, green finance has a synergistic effect on SO2 and carbon reduction, but not on reduction of dust and carbon emissions. Our findings suggest that green finance reduces emissions by improving corporate energy utilization efficiency. Furthermore, we find that the effects of green finance on emission reduction are more significant among non-state and non-listed firms. These findings have important implications for the development of green finance and synergistic reduction of air pollutants and carbon.

Gut microbiome reveals contrasting enterotypes and health statuses of semi-wild Saiga antelopes (Saiga tatarica)

Gut microbiome studies based on fecal samples can non-invasively reflect the survival and health status of endangered species. This study presents the first characterization of the gut microbiome in the semi-wild population of the critically endangered Saiga antelope (Saiga tatarica), unveiling the existence of two distinct enterotypes within the semi-wild Saiga: the Oscillospiraceae UCG-005 enterotype and the Arthrobacter enterotype. These enterotypes show significant differences in microbiome diversity, composition, and predicted functions. The Arthrobacter enterotype has lower alpha diversity, fewer short-chain fatty acids (SCFAs)-producing bacteria, more potential pathogens, lower energy metabolism and higher lipid metabolism abundance. The findings imply that Saiga with the Arthrobacter enterotype have lower energy utilization efficiency and higher disease risks, particularly for obesity. Microbial correlation network analysis indicates SCFAs-producing bacteria play a key role in the formation of these enterotypes. This suggests that next-generation probiotics, primarily composed of SCFAs-producing bacteria, could be used to regulate and improve the health of the Saiga. Additionally, the similarity of the enterotype associated with a healthier survival state to that of wild counterparts suggests that incorporating gut microbiome monitoring into the key indicators for the reintroduction of endangered species could be significant for wildlife conservation and management.

An efficient acoustic energy harvester by using deep learning-based traffic prediction

With rapid urbanisation, traffic noise pollution has become a growing community concern. However, traffic noise can be valuable due to its ubiquity and cleanliness, which can be exploited for acoustic energy harvesting systems. This paper aims to develop an efficient acoustic energy harvester to improve energy utilisation efficiency and reduce noise levels by using deep-learning methods. We propose a temporal graph attention convolutional network (TGACN) to predict noise frequency, providing guidance for the acoustic energy harvester design. Power efficiency can be maximised by adjusting the harvester's neck size to the frequency predicted by the TGACN model. The relationship between neck size and the optimum frequency range is obtained through simulations and experiments. We analysed the performance differences among the various cavities in multiple-cavity acoustic energy harvesters and discussed the circuit connection methods between each cavity to identify the optimal configurations. Additionally, we evaluated the superiority of TGACN over the state-of-the-art methods in terms of prediction accuracy by conducting extensive experiments with two real-world datasets.

Strategy to Enhance Air Electrode Performance and Durability in Soe and Co-Soe Modes: Composite Electrode with a Gradually Changing Composition

Among the key challenges of the Solid Oxide Cell (SOC) is stable, long-term operation in electrolysis (SOE, Solid Oxide Electrolysis), and co-electrolysis (co-SOE) modes. Many factors impact the SOC’s lifespan, i.e., the chemical composition of the fuel and air electrode, the type of the cell, and working conditions (e.g., current density, temperature). Therefore, the development of high-performance and durable cells seems to be crucial, as SOE/co-SOE systems may play an important role in the ongoing transformation toward a climate-neutral economy (low-emission hydrogen production; efficient utilization of CO2and renewable energy) [1,2].One of the crucial degradation mechanisms of SOC in electrolysis/co-electrolysis mode is the delamination of the air electrode, caused by the accumulation of high oxygen partial pressure on the interphase of the electrolyte, the formation of additional phases, and/or reaction of voids/cracks in the electrolyte or buffer layer [2,3]. A strategy to mitigate the risk of air electrode delamination is to use composite electrode based on the buffer layer material (GDC- Gd0,1Ce0,9O2) and state-of-the-art electrode – LSC (La0,6Sr0,4CoO3-δ), as it will lower the effect of the thermal expansion mismatch between the electrode and buffer layer/electrolyte. Moreover, by manipulating the microstructure of the electrode, e.g., by introducing a pore-forming agent, it is possible to ensure fast and effective collection of oxygen generated during operation in the SOE/co-SOE mode on the air side (preventing potential differences leading to the stresses on the electrode-electrolyte interface).In this study, the electrochemical performance of solid oxide cells with a modified, gradually changing composite LSC-GDC air electrode was verified in electrolysis and co-electrolysis modes. The following air electrode compositions were proposed for cell preparation: type 1: 1st layer 50LSC:50CGO, 2nd layer: 75LSC: 25GDC, 3rd layer: LSC, type 2: 1st layer 75LSC:25CGO, 2nd and 3rd layers: LSC with PMMA as a pore former; type 3: 1st layer 75LSC:25CGO, 2nd and 3rd layers: 90LSC:10GDC, and type 4: 1st layer 85LSC:15CGO, 2nd layer: 90LSC:10GDC; 3rd layer: LSC with PMMA as a pore former. The proposed air electrode was tested at the single-cell level (cells size of 50 mm x 50 mm), and the most promising solutions were implemented in the SOC stack (a stack consisting of 3-5 cells with a size of 110 mm x 110 mm). The electrochemical analysis of the developed cells includes measurements of the j-V dependences and EIS spectra under different modes (SOE and co-SOE), various temperatures, current densities, and different gas flows delivered at the air side of the cell. The microstructure, morphology, and composition of the prepared cells and samples after testing were analyzed using SEM, SEM-EDS, and, for selected samples, the FIB-SEM method. The obtained results showed that by a gradually changing the electrode composition, specifically by reducing the GDC content in the electrode, it is possible to obtain a stable electrode (a strategy to prevent air electrode delamination) with high catalytic activity in both electrolysis and co-electrolysis modes. The composite GDC-LSC electrodes with various compositions seem to be promising air electrodes for SOE and co-SOE systems. The study achieves relatively high current densities compared to the SoA cells, with only negligible degradation changes observed after long-term testing (>300 h in single cell configuration). Acknowledgments The presented research was financially supported by: the National Centre for Research and Development, Poland, within project no. LIDER/1/0003/L-12/20/NCBR/2021, which focuses on research related to composite electrodes. Anna Niemczyk acknowledges support from the Foundation for Polish Science (FNP) through a scholarship from the START program. References B. Mogensen et al., Clean Energy 3 (2019) 175; DOI: 10.1093/ce/zkz023Hauch, P. Blennow, Solid State Ionics 391 (2023) 116127; DOI: 10.1016/j.ssi.2022.116127Subotić, C. Hochenauer, Progress in Energy and Combustion Science 93 (2022) 101011; DOI: 10.1016/j.pecs.2022.101011

Compact Energy Storage Devices Developed from Waste-Derived Electrodes via Facile Recycling Technology

Indeed, the development of sustainable and renewable energy technologies is a critical aspect of addressing the challenges posed by pollution and climate change. Electrochemical energy storage devices, such as batteries and supercapacitors, play a crucial role in this transition by enabling the efficient storage and utilization of energy. The mention of nanomaterials-based electrodes highlights a fascinating area of research and innovation. Nanomaterials offer unique properties and advantages due to their small size, high surface area, short-diffusion path, rapid kinetics, enhanced conductivity, making them highly desirable for energy storage applications.Recycling waste to electrodes in compact energy storage device represents a particularly exciting frontier. Integrating energy storage into advance technology can enhance the portability and convenience of power sources, especially in the context of emerging technologies like wearable electronics and smart devices. However, challenges such as scalability, cost-effectiveness, and environmental impact must also be addressed to ensure the widespread adoption of these technologies. The emphasis on carbon-based nanomaterials, including graphene, carbon quantum dots, and activated carbon, as electrode materials is noteworthy. These materials show promise not only as negative electrodes but also as positive electrodes when combined with metal oxides, hydroxides, or sulphides, demonstrating their versatility in energy storage applications. Additionally, the innovative use of waste recycling, such as tires, shoots, and dry cells, for extracting carbon aligns with the broader goal of creating an eco-friendly environment. The focus on developing carbon-based electrodes from recycled waste for energy storage devices is commendable, as it not only addresses environmental concerns but also contributes to the creation of stable and efficient energy storage systems. In conclusion, this work on the generation of efficient carbon-based electrodes (graphene derived from different waste materials) for energy storage devices, showcases a multidisciplinary approach that considers both environmental sustainability and technological advancement. This research has the potential to contribute significantly to the ongoing efforts to create a more sustainable and efficient energy landscape.Key words: Recycling, Electrochemical, Carbon, Metal oxides, Energy storage, Compact devices

Energetic, exergetic and economic analysis of a trans-critical solar hybrid CCHP system

A solar hybrid CCHP (combination of cooling, heating and power) system was proposed to organically integrate the Brayton and reverse Carnot cycle by trans-critical CO2 working medium. The transient thermal storage in a solar hybrid CCHP system (SCCHP) was designed to overcome the energy coupling challenges in regions rich in solar and gas resources. Moreover, the incorporation of an optimally efficient throttling expander in cooling cycle was designed to enhance energy utilization efficiency. The thermodynamic performance of the SCCHP system was systematically evaluated by comparing with the ejector hybrid CCHP system from energetic, exergetic, and economic perspectives. The results suggest that elevating the intake pressure of both the high-pressure compressor from 5.2 kW to 6.4 kW and turbine from 7.3 kW to 7.8 kW, led to an enhancement in the COP of the SCCHP system. Moreover, raising the turbine intake temperatures from 483.15 K to 503.15 K yielded a significant improvement in system energy efficiency from 0.66 to 0.71 and COP from 1.58 to 1.72. Furthermore, in contrast to the ECHP system, the components in the SCCHP system demonstrated not only less exergy efficiency variation to the influence of ambient temperature but also lower hourly economic costs. The SCCHP has an average hourly investment cost that is 5.70 USD (kgh)−1 lower than ECHP, and its economic efficiency improves with higher ambient temperatures.

Workpiece surface laser regulation in laser-induced plasma electrolyte jet machining: Position, shape, and energy

Laser-induced plasma electrolyte jet machining is a new hybrid machining method. This machining method utilizes the plasma impact effect and plasma to increase the inter-pole conductivity for material removal, with low laser energy loss, high material removal rate (MRR), and good surface quality. The advantages of laser machining and electrolyte jet machining are fully utilized. However, it is difficult to avoid refraction of the laser in the electrolyte column, which affects the efficient coupling of the laser to the electrolyte jet machining. In this paper, to improve the localization and MRR, a study is carried out to address the problem of energy utilization efficiency in laser-induced plasma electrolyte jet machining. A compensation model for the refraction of the laser beam in the electrolyte is proposed. Compensation improves the shape and positional accuracy of the laser beam coupled to the electrolyte beam during aluminum alloy machining. Compared before and after compensation, the MRR was improved by 30.2 %, and the groove localization was improved by 37.4 %. Realization of high energy coupling for laser electrolyte jet hybrid machining.

A high-efficiency poly-input boost DC–DC converter for energy storage and electric vehicle applications

This research paper introduces an avant-garde poly-input DC–DC converter (PIDC) meticulously engineered for cutting-edge energy storage and electric vehicle (EV) applications. The pioneering converter synergizes two primary power sources—solar energy and fuel cells—with an auxiliary backup source, an energy storage device battery (ESDB). The PIDC showcases a remarkable enhancement in conversion efficiency, achieving up to 96% compared to the conventional 85–90% efficiency of traditional converters. This substantial improvement is attained through an advanced control strategy, rigorously validated via MATLAB/Simulink simulations and real-time experimentation on a 100 W test bench model. Simulation results reveal that the PIDC sustains stable operation and superior efficiency across diverse load conditions, with a peak efficiency of 96% when the ESDB is disengaged and an efficiency spectrum of 91–95% during battery charging and discharging phases. Additionally, the integration of solar power curtails dependence on fuel cells by up to 40%, thereby augmenting overall system efficiency and sustainability. The PIDC’s adaptability and enhanced performance render it highly suitable for a wide array of applications, including poly-input DC–DC conversion, energy storage management, and EV power systems. This innovative paradigm in power conversion and management is poised to significantly elevate the efficiency and reliability of energy storage and utilization in contemporary electric vehicles and renewable energy infrastructures.

Self‐Powered Supercapacitor with Bifunctional Separator in Suppressing Self‐Discharge

AbstractIntegrating energy harvesters with energy storage devices helps enhance energy utilization efficiency. The requirement for external power sources in energy storage devices can also be addressed by the development of an all‐in‐one single system. Vegetable peels can be used as piezoelectric energy harvesters due to the generation of electric dipole within cellulose. The self‐discharge processes cause open circuit potential decay, resulting in a loss of energy stored within the cell. The self‐discharge rate can be controlled by using a piezoelectric separator. This work used garlic skins as a piezoelectric separator, which helped delay the self‐discharge rate. The supercapacitor using Ni−Mn oxide as positive and Fe−Ni sulfide/RGO as negative electrode materials was fabricated with garlic skin as a separator. The device was charged from an initial OCP of ~0.15–~0.37 V in ~ 4 sec by finger tapping. The OCP decay rate was reduced by~88 % compared to that of using the Whatmann separator. The fabricated Ni−Mn oxide RGO/garlic skin/FeS2 RGO exhibited ~72.2 W h kg−1 energy density at a power density of ~2 kW kg−1 in an operated potential window of ~2 V. This research provides a cost‐effective method for developing piezoelectric supercapacitor with low self‐discharge rate.

Study of a Novel Updraft Tower Power Plant Combined with Wind and Solar Energy

This study presents a novel solar updraft tower power plant (SUTPP) system, which has been designed to achieve the simultaneous utilization of solar and wind energy resources in desert regions, in response to the pressing demand for sustainable and efficient renewable energy solutions. The aim of this research was to develop an integrated system that is capable of harnessing and converting these abundant energy sources into electrical power, thereby enhancing the renewable energy portfolio in arid environments. The methodology of this study involved the design and construction of a prototype SUTPP, comprising a 53 m high tower, a 6170 m2 collector, five horizontal-axis wind turbines, and a thermal energy storage layer made up of pebbles and sand. The experimental setup was meticulously detailed, and experiments were conducted to collect data on the system’s performance under various environmental conditions. Subsequently, three-dimensional numerical simulations were performed to explore the effects of ambient wind speed and solar radiation on the output power of the SUTPP. The results indicate that the output power of the system increases with the increase in ambient wind speed and solar radiation. The impact of solar irradiation on output power was observed to diminish as ambient wind speeds increased. Notably, as the inlet wind speed rose from 4 m/s to 12 m/s, the output power showed a substantial increase of 727%. The numerical simulations revealed that ambient wind speed has a more pronounced effect on power output compared to solar radiation. Furthermore, it was found that the influence of solar radiation is significant at low wind speeds, with its impact decreasing as wind speed increases. This research provides essential guidance for the design and engineering of highly efficient solar thermal energy utilization projects, representing a significant advancement in the field of renewable energy technology deployment in desert environments.

Parametric optimization for enhancing the electrical performance of hybrid photovoltaic/thermal and thermally regenerative electrochemical cycle system

Globally, the efficient utilization of solar energy has garnered significant attention. A hybrid system of photovoltaic/thermal (PV/T) modules integrated with thermally regenerative electrochemical cycle (TREC), i.e., PV/T-TREC has emerged recently and shows higher efficiency for solar-to-electrical conversion than a standalone PV system. However, there is a trade-off between the electricity generation from PV/T and TREC because the thermal energy from PV/T degrades the efficiency of the PV/T but improves that of TREC. Previous studies have failed to investigate this problem. This study therefore focuses on the key parameters that significantly affect the thermal output of PV/T, i.e., different PV materials, air gaps, heat storage tank volumes, and working fluids to investigate the maximum electrical efficiency of the hybrid system. The mathematical and transient-state numerical models are developed with the validation/refinement from the experiments. The results show that the hybrid system with PV material of cadmium telluride presents the best overall electrical efficiency of 25.37 %. The case of the air gap fosters the solar-to-electrical conversion. The electrical efficiency versus heat storage tank volume shows a convex curve, peaking at 200 L. The nanofluid performs the best. This study may help guide the practical application of such a high-efficiency electricity generation system.

Assessing opportunities for enhanced lighting energy conservation via occupancy and daylight monitoring

Efficient energy utilization in buildings is crucial for sustainability. This work proposes an intelligent system that leverages computer vision techniques and CCTV images to assess indoor lighting energy usage based on occupancy, artificial lighting, and daylight conditions. Object detection models - You Only Look Once (YOLO) version 3 (v3) and v8 are employed to detect people, lights, and windows, achieving promising accuracies of 94.9 ​%, 73.3 ​%, and 98.7 ​%, respectively. The system categorizes scenarios as energy-efficient, wasteful, or neutral by integrating these outputs, highlighting opportunities for improving efficiency by harmonizing lighting infrastructure with occupancy and daylight exposure. Performance analyses, including training and validation metrics, are presented. This study demonstrates the potential of computer vision and AI for optimizing energy utilization, enabling sustainable building operation and promoting energy-positive occupant behaviors through sensor-driven methodologies.