Pub Date : 2024-09-21DOI: 10.1016/j.renene.2024.121430
Proton exchange membrane fuel cell (PEMFC) exhibits significant promise in generating power from hydrogen energy. Operating parameters exert a direct influence on both the power output and the uniformity of oxygen distribution within the PEMFC. Therefore, quantifying the impact of operating parameters and identifying the optimal operating conditions are pivotal to enhance the performance and extend the lifespan of the PEMFC. To this end, a two-stage framework leveraging interpretable machine learning and multi-objective optimization is proposed. In the first stage, an interpretable surrogate model for the PEMFC is established. The impacts of single parameter and pairwise parameters on the power output and the oxygen distribution quality are quantified. Moreover, the decision variables are selected for the second stage. In the second stage, the optimal operating parameters are determined via multi-objective optimization. The results from the first stage suggest that operating voltage and pressure have the highest cumulative contribution for both power density and oxygen distribution quality. The influence mechanism of one operating parameter on the relationship between another operating parameter and the research target is clearly quantified. The findings from the second stage indicate that power density increases by 32 %, 27.36 %, and 32.58 % for three optimized solutions, respectively, while the standard deviation of oxygen molar concentration in the selected operating condition is reduced by 29.66 %.
{"title":"A two-stage framework for quantifying the impact of operating parameters and optimizing power density and oxygen distribution quality of PEMFC","authors":"","doi":"10.1016/j.renene.2024.121430","DOIUrl":"10.1016/j.renene.2024.121430","url":null,"abstract":"<div><div>Proton exchange membrane fuel cell (PEMFC) exhibits significant promise in generating power from hydrogen energy. Operating parameters exert a direct influence on both the power output and the uniformity of oxygen distribution within the PEMFC. Therefore, quantifying the impact of operating parameters and identifying the optimal operating conditions are pivotal to enhance the performance and extend the lifespan of the PEMFC. To this end, a two-stage framework leveraging interpretable machine learning and multi-objective optimization is proposed. In the first stage, an interpretable surrogate model for the PEMFC is established. The impacts of single parameter and pairwise parameters on the power output and the oxygen distribution quality are quantified. Moreover, the decision variables are selected for the second stage. In the second stage, the optimal operating parameters are determined via multi-objective optimization. The results from the first stage suggest that operating voltage and pressure have the highest cumulative contribution for both power density and oxygen distribution quality. The influence mechanism of one operating parameter on the relationship between another operating parameter and the research target is clearly quantified. The findings from the second stage indicate that power density increases by 32 %, 27.36 %, and 32.58 % for three optimized solutions, respectively, while the standard deviation of oxygen molar concentration in the selected operating condition is reduced by 29.66 %.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.renene.2024.121381
The representation of flow across influential spatiotemporal scales introduces a challenge when micro-siting tidal stream turbine arrays. Robust representative approximations could accelerate design optimisation, yet there is no consensus on what defines the most appropriate flow conditions. We summarise existing approaches to representative flow field selection for array optimisation and propose an objective-driven process. The method curates a subset of flow fields that best captures relevant dynamics, enabling the streamlined representation of tidal cycles. To demonstrate the method, we consider flow modelling data in the Inner Sound of the Pentland Firth, Scotland, UK. We examine the impact of flow field inputs to array design through comparative analyses using a heuristic array optimisation process. Results indicate notable sensitivity of the turbine layout to the flow conditions selected. For the case study presented, our method led to 4%–5% energy yield prediction improvements relative to use of simple time-interval based approaches and up to 2% improvement against using peak flow fields; these can be pivotal margins to secure feasibility by developers. We also find that using the data associated with a single monitored point across the array for flow field selection can lead to sub-optimal results, emphasising the need for accurate spatiotemporal representation.
{"title":"Objective representative flow field selection for tidal array layout design","authors":"","doi":"10.1016/j.renene.2024.121381","DOIUrl":"10.1016/j.renene.2024.121381","url":null,"abstract":"<div><div>The representation of flow across influential spatiotemporal scales introduces a challenge when micro-siting tidal stream turbine arrays. Robust representative approximations could accelerate design optimisation, yet there is no consensus on what defines the most appropriate flow conditions. We summarise existing approaches to representative flow field selection for array optimisation and propose an objective-driven process. The method curates a subset of flow fields that best captures relevant dynamics, enabling the streamlined representation of tidal cycles. To demonstrate the method, we consider flow modelling data in the Inner Sound of the Pentland Firth, Scotland, UK. We examine the impact of flow field inputs to array design through comparative analyses using a heuristic array optimisation process. Results indicate notable sensitivity of the turbine layout to the flow conditions selected. For the case study presented, our method led to 4%–5% energy yield prediction improvements relative to use of simple time-interval based approaches and up to 2% improvement against using peak flow fields; these can be pivotal margins to secure feasibility by developers. We also find that using the data associated with a single monitored point across the array for flow field selection can lead to sub-optimal results, emphasising the need for accurate spatiotemporal representation.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0960148124014496/pdfft?md5=1ba2c4d65ee74d87408e12345ac1640b&pid=1-s2.0-S0960148124014496-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.renene.2024.121438
This study introduces a novel polygeneration system that integrates biomass gasification, anaerobic digestion, photovoltaic (PV) energy, and electrolysis to enhance system flexibility and efficiency. The system includes an allothermal gasification unit that processes lignocellulosic biomass sourced from a botanical garden. The gasifying agent, either steam or oxygen, is supplied by an alkaline electrolyzer, which operates under a Power-to-X strategy, utilizing surplus energy from a PV field. The resulting syngas and hydrogen are blended with biogas from an anaerobic digester, which treats municipal waste, to power a cogenerator. This cogenerator meets the electricity, heating, and cooling demands of a hospital, while the PV field powers the botanical garden. The systems components are modeled using various tools and integrated into the TRNSYS environment for dynamic simulation. An exergy analysis identifies the main sources of exergy destruction, while a thermo-economic analysis evaluates the energy, environmental, and economic impacts of a demonstration plant located in Bogotá’s Botanical Garden. Simulation results show that the system achieves an overall exergy efficiency of around 35 %, with a 96 % reduction in primary energy consumption compared to a reference system, avoiding nearly 6000 tons of CO2 emissions annually. From an economic perspective, the system is profitable, with a payback period of 3.02 years and a Net Present Value of $15.23 million, almost double the capital cost. The gasification unit's exergy efficiency is significantly higher when using oxygen (0.50) compared to steam (0.25), underscoring the importance of integrating electrolysis for improved biomass conversion. The alkaline electrolyzer operates efficiently within its optimal range, with an energy efficiency close to 0.70 and an exergy efficiency around 0.60, effectively utilizing 25 % of the total PV production.
{"title":"Exergy and thermoeconomic analysis of a novel polygeneration system based on gasification and power-to-x strategy","authors":"","doi":"10.1016/j.renene.2024.121438","DOIUrl":"10.1016/j.renene.2024.121438","url":null,"abstract":"<div><div>This study introduces a novel polygeneration system that integrates biomass gasification, anaerobic digestion, photovoltaic (PV) energy, and electrolysis to enhance system flexibility and efficiency. The system includes an allothermal gasification unit that processes lignocellulosic biomass sourced from a botanical garden. The gasifying agent, either steam or oxygen, is supplied by an alkaline electrolyzer, which operates under a Power-to-X strategy, utilizing surplus energy from a PV field. The resulting syngas and hydrogen are blended with biogas from an anaerobic digester, which treats municipal waste, to power a cogenerator. This cogenerator meets the electricity, heating, and cooling demands of a hospital, while the PV field powers the botanical garden. The systems components are modeled using various tools and integrated into the TRNSYS environment for dynamic simulation. An exergy analysis identifies the main sources of exergy destruction, while a thermo-economic analysis evaluates the energy, environmental, and economic impacts of a demonstration plant located in Bogotá’s Botanical Garden. Simulation results show that the system achieves an overall exergy efficiency of around 35 %, with a 96 % reduction in primary energy consumption compared to a reference system, avoiding nearly 6000 tons of CO<sub>2</sub> emissions annually. From an economic perspective, the system is profitable, with a payback period of 3.02 years and a Net Present Value of $15.23 million, almost double the capital cost. The gasification unit's exergy efficiency is significantly higher when using oxygen (0.50) compared to steam (0.25), underscoring the importance of integrating electrolysis for improved biomass conversion. The alkaline electrolyzer operates efficiently within its optimal range, with an energy efficiency close to 0.70 and an exergy efficiency around 0.60, effectively utilizing 25 % of the total PV production.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.renene.2024.121427
Climate finance (CF) is considered to be a key financial innovation to enhance energy efficiency (EE) and facilitate the pathway to energy transition (ET). However, the varied impacts of CF on EE and renewable energy production (REP) have been masked. Thus, this study examines the heterogeneous impacts of CF on EE and REP for 81 developing countries (DCs) for the period 2002–2019. The method of moments quantile regression (MMQR) approach is used to control for distributional and unobserved individual heterogeneity. We calculate EE using parametric stochastic frontier analysis (SFA). Also, the effects of CF on EE and REP are investigated subject to income heterogeneity and based on Copenhagen (COP15) and Paris (COP21) climate accords. The findings revealed that DCs with lower REP benefit the most from increased CF, and the positive effects break down for countries with the largest distributions of REP. Besides, CF positively contributes to EE across all quantiles of DCs. The results further imply that the impacts of CF are income-dependent, with positive effects on the EE and REP of middle-income economies and more pronounced after the COP15 and COP21 climate accords. Several policy implications are forwarded based on the findings.
{"title":"The heterogeneous impacts of climate finance on energy efficiency and renewable energy production in developing countries","authors":"","doi":"10.1016/j.renene.2024.121427","DOIUrl":"10.1016/j.renene.2024.121427","url":null,"abstract":"<div><div>Climate finance (CF) is considered to be a key financial innovation to enhance energy efficiency (EE) and facilitate the pathway to energy transition (ET). However, the varied impacts of CF on EE and renewable energy production (REP) have been masked. Thus, this study examines the heterogeneous impacts of CF on EE and REP for 81 developing countries (DCs) for the period 2002–2019. The method of moments quantile regression (MMQR) approach is used to control for distributional and unobserved individual heterogeneity. We calculate EE using parametric stochastic frontier analysis (SFA). Also, the effects of CF on EE and REP are investigated subject to income heterogeneity and based on Copenhagen (COP15) and Paris (COP21) climate accords. The findings revealed that DCs with lower REP benefit the most from increased CF, and the positive effects break down for countries with the largest distributions of REP. Besides, CF positively contributes to EE across all quantiles of DCs. The results further imply that the impacts of CF are income-dependent, with positive effects on the EE and REP of middle-income economies and more pronounced after the COP15 and COP21 climate accords. Several policy implications are forwarded based on the findings.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.renene.2024.121437
Cities serve as the epicenter of energy consumption, and urban energy transition (UET) is a pivotal prerequisite for achieving carbon peaking and neutrality goals. Leveraging the quasi-natural experiment of China's New Energy Demonstration City Construction (NEDCC), this paper evaluates its impact on UET based on balanced panel data spanning 272 cities from 2006 to 2022. Employing the difference-in-differences model, our estimates underscore NEDCC's facilitative role in promoting UET, a finding corroborated by a series of robustness tests. Mechanism examinations reveal that NEDCC advances UET by enhancing government strategic guidance, fostering green technological innovation, promoting industrial structural upgrading, and optimizing resource allocation efficiency. Furthermore, in cities with higher administrative tiers and more advanced digital finance, NEDCC exerts a more pronounced effect on UET. Conversely, cities endowed with richer resources and pursuing more ambitious economic growth targets exhibit weaker responses to NEDCC's UET-boosting influence. Additionally, NEDCC's demonstration effect surpasses its diffusion effect on neighboring cities, generating a positive spatial spillover that propels their energy transitions. This study offers a novel policy lens for advancing UET.
{"title":"Exploring the path to promote energy revolution: Assessing the impact of new energy demonstration city construction on urban energy transition in China","authors":"","doi":"10.1016/j.renene.2024.121437","DOIUrl":"10.1016/j.renene.2024.121437","url":null,"abstract":"<div><div>Cities serve as the epicenter of energy consumption, and urban energy transition (UET) is a pivotal prerequisite for achieving carbon peaking and neutrality goals. Leveraging the quasi-natural experiment of China's New Energy Demonstration City Construction (NEDCC), this paper evaluates its impact on UET based on balanced panel data spanning 272 cities from 2006 to 2022. Employing the difference-in-differences model, our estimates underscore NEDCC's facilitative role in promoting UET, a finding corroborated by a series of robustness tests. Mechanism examinations reveal that NEDCC advances UET by enhancing government strategic guidance, fostering green technological innovation, promoting industrial structural upgrading, and optimizing resource allocation efficiency. Furthermore, in cities with higher administrative tiers and more advanced digital finance, NEDCC exerts a more pronounced effect on UET. Conversely, cities endowed with richer resources and pursuing more ambitious economic growth targets exhibit weaker responses to NEDCC's UET-boosting influence. Additionally, NEDCC's demonstration effect surpasses its diffusion effect on neighboring cities, generating a positive spatial spillover that propels their energy transitions. This study offers a novel policy lens for advancing UET.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.renene.2024.121426
This study comprehensively evaluates the performance and operational challenges of a 9 MW grid-connected photovoltaic (PV) system in Timmimoun, southern Algeria, after eight years of operation. We identified a significant linear correlation (R2 = 0.73) between increased ambient temperatures and decreased PV module efficiency, underscoring the need for effective thermal management strategies. The investigation also examines potential solutions, such as cooling mechanisms, optimization of panel orientation and tilt angles, and development of temperature-resistant materials. Adhering to the International Energy Agency IEC 61724 standard, our analysis reveals a yield factor of 5.04 h/day, a yield ratio of 7.04 h/day, a performance ratio of 73 %, and a capacity factor of 21 % in 2023. Over its operational lifespan, the system has generated 133.43 GW h of energy, mitigating 1.01 105 tons of CO2 emissions. This long-term study provides critical insights into the performance and reliability of PV systems in hot desert climates, offering valuable guidance for future large-scale solar installations and contributing to the transition towards a sustainable energy future.
{"title":"Long-term performance analysis of a large-scale photoVoltaic plant in extreme desert conditions","authors":"","doi":"10.1016/j.renene.2024.121426","DOIUrl":"10.1016/j.renene.2024.121426","url":null,"abstract":"<div><div>This study comprehensively evaluates the performance and operational challenges of a 9 MW grid-connected photovoltaic (PV) system in Timmimoun, southern Algeria, after eight years of operation. We identified a significant linear correlation (R<sup>2</sup> = 0.73) between increased ambient temperatures and decreased PV module efficiency, underscoring the need for effective thermal management strategies. The investigation also examines potential solutions, such as cooling mechanisms, optimization of panel orientation and tilt angles, and development of temperature-resistant materials. Adhering to the International Energy Agency IEC 61724 standard, our analysis reveals a yield factor of 5.04 h/day, a yield ratio of 7.04 h/day, a performance ratio of 73 %, and a capacity factor of 21 % in 2023. Over its operational lifespan, the system has generated 133.43 GW h of energy, mitigating 1.01 10<sup>5</sup> tons of CO<sub>2</sub> emissions. This long-term study provides critical insights into the performance and reliability of PV systems in hot desert climates, offering valuable guidance for future large-scale solar installations and contributing to the transition towards a sustainable energy future.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.renene.2024.121424
Globally, the adverse climate effects caused by greenhouse gas emissions are becoming increasingly apparent, and solutions to increase the use of eco-friendly transportation methods are urgently needed. Introducing solar-powered vehicles (SPVs), which are cars integrated with solar panels capable of generating power, presents a promising solution to reduce urban carbon footprints. However, the low adoption rate of SPVs implies that the benefits—such as environmental friendliness and ability to charge while driving—need to be more palpably experienced by consumers. To address this aspect, in this study, we aimed to develop a navigation system algorithm that guides users along routes that optimize energy consumption and solar energy production from the starting point to the destination. This was done with the objective of providing more tangible benefits from using SPVs. The study focused on the high-traffic urban center of Seoul, where determining solar power availability for a moving SPV is challenging, given the presence of shadows cast by roadside features such as buildings and trees. To achieve this, panoramic images from Google Street View were collected at 10 m intervals from all roads within the research area. From these images, sky and non-sky elements were separated. Subsequently, a hemispherical map was constructed and superimposed with the sun's path. The presence of shadows was determined by assessing whether the sun's path was obstructed by non-sky elements; if the path was unimpeded in the sky, no shadow was recorded. The shadow data obtained at each spot were efficiently stored in a database for quick retrieval and application based on specific locations and departure times. Using this shadow information, the navigation algorithm calculates power generation along a given route and considers the energy consumption of the SPV. Analysis led to the identification of an energy-saving route, which enabled the achievement of energy conservation and CO2 reduction benefits. Furthermore, a comprehensive sensitivity analysis was conducted to examine the impact of four critical parameters—module efficiency, solar panel area, vehicle speed, and departure time—on route selection and net energy consumption. The energy-saving path planning algorithm enhances the economic feasibility of solar charging for SPVs during travel; thus, this study can contribute significantly to the widespread adoption of SPVs, which play a definitive role in reducing transportation's carbon footprint.
{"title":"Energy-saving path planning navigation for solar-powered vehicles considering shadows","authors":"","doi":"10.1016/j.renene.2024.121424","DOIUrl":"10.1016/j.renene.2024.121424","url":null,"abstract":"<div><div>Globally, the adverse climate effects caused by greenhouse gas emissions are becoming increasingly apparent, and solutions to increase the use of eco-friendly transportation methods are urgently needed. Introducing solar-powered vehicles (SPVs), which are cars integrated with solar panels capable of generating power, presents a promising solution to reduce urban carbon footprints. However, the low adoption rate of SPVs implies that the benefits—such as environmental friendliness and ability to charge while driving—need to be more palpably experienced by consumers. To address this aspect, in this study, we aimed to develop a navigation system algorithm that guides users along routes that optimize energy consumption and solar energy production from the starting point to the destination. This was done with the objective of providing more tangible benefits from using SPVs. The study focused on the high-traffic urban center of Seoul, where determining solar power availability for a moving SPV is challenging, given the presence of shadows cast by roadside features such as buildings and trees. To achieve this, panoramic images from Google Street View were collected at 10 m intervals from all roads within the research area. From these images, sky and non-sky elements were separated. Subsequently, a hemispherical map was constructed and superimposed with the sun's path. The presence of shadows was determined by assessing whether the sun's path was obstructed by non-sky elements; if the path was unimpeded in the sky, no shadow was recorded. The shadow data obtained at each spot were efficiently stored in a database for quick retrieval and application based on specific locations and departure times. Using this shadow information, the navigation algorithm calculates power generation along a given route and considers the energy consumption of the SPV. Analysis led to the identification of an energy-saving route, which enabled the achievement of energy conservation and CO<sub>2</sub> reduction benefits. Furthermore, a comprehensive sensitivity analysis was conducted to examine the impact of four critical parameters—module efficiency, solar panel area, vehicle speed, and departure time—on route selection and net energy consumption. The energy-saving path planning algorithm enhances the economic feasibility of solar charging for SPVs during travel; thus, this study can contribute significantly to the widespread adoption of SPVs, which play a definitive role in reducing transportation's carbon footprint.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.renene.2024.121434
Model pyrolysis oil (bio-oil) is a promising bio-fuel with complex and unstable contents, making its fast characterization an essential demand in industrial production. This study proposed an integrated machine learning framework to predict elemental composition, low heating value, and unsaturated concentration from infrared spectra, achieving fast and interpretable characterization of bio-oil. In the integrated framework, a peak loading-based strategy was used to dimensionally reduce the spectral data. Bayesian optimized random forest (RF) and extreme gradient boosting (XGBoost) models were used to predict bio-oil properties from dimensionally reduced spectral data. Ensemble learning was used to combine RF and XGBoost models together for better predicting performance. Results showed that the proposed characterization method achieved an average accuracy of 99.53 %, a low RMSE value of 0.726, and an R2 of 0.98. The Shapley value analysis revealed that the vibration of NH2 stretch (1594 cm−1), C-H stretch (2868 cm−1), and C-N stretch in the aromatic ring (1229 cm−1) have a significant contribution to the characterization results. The working mechanism of the proposed characterization method was interpreted by the internal relationship among spectral peak location/height, functional group species/amount, and the predicted characteristics. The results are hoped to serve quality control in production of bio-oil.
{"title":"Combination of integrated machine learning model frameworks and infrared spectroscopy towards fast and interpretable characterization of model pyrolysis oil","authors":"","doi":"10.1016/j.renene.2024.121434","DOIUrl":"10.1016/j.renene.2024.121434","url":null,"abstract":"<div><div>Model pyrolysis oil (bio-oil) is a promising bio-fuel with complex and unstable contents, making its fast characterization an essential demand in industrial production. This study proposed an integrated machine learning framework to predict elemental composition, low heating value, and unsaturated concentration from infrared spectra, achieving fast and interpretable characterization of bio-oil. In the integrated framework, a peak loading-based strategy was used to dimensionally reduce the spectral data. Bayesian optimized random forest (RF) and extreme gradient boosting (XGBoost) models were used to predict bio-oil properties from dimensionally reduced spectral data. Ensemble learning was used to combine RF and XGBoost models together for better predicting performance. Results showed that the proposed characterization method achieved an average accuracy of 99.53 %, a low RMSE value of 0.726, and an R<sup>2</sup> of 0.98. The Shapley value analysis revealed that the vibration of NH<sub>2</sub> stretch (1594 cm<sup>−1</sup>), C-H stretch (2868 cm<sup>−1</sup>), and C-N stretch in the aromatic ring (1229 cm<sup>−1</sup>) have a significant contribution to the characterization results. The working mechanism of the proposed characterization method was interpreted by the internal relationship among spectral peak location/height, functional group species/amount, and the predicted characteristics. The results are hoped to serve quality control in production of bio-oil.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.renene.2024.121429
Paper sludge is a solid waste in paper mills and is conventionally treated by, e.g., landfill, composting, and incineration. Paper sludge contains paper production fillers and lignocellulosic biomass, both of which can be recycled to recover circular minerals and produce bio-based fuels and chemicals by, e.g., thermochemical recycling technology namely fast pyrolysis, for circular bioeconomy. In this paper, three different paper sludge samples collected in The Netherlands and Spain were analyzed by thermogravimetric analysis, moisture analysis, ash analysis, CHNS elemental analysis, powder X-ray diffraction, and X-ray fluorescence spectrometry. Fast pyrolysis of paper sludge was carried out in a lab-scale continuous stirred tank reactor at 500 ± 10 °C with a paper sludge feeding rate of 1 kg h−1. The recovery of circular minerals, which are mainly calcium carbonate, is 87.1 ± 2.2 % (on mineral basis). The yields of fast pyrolysis bio-liquid and biochar are 49.2 ± 6.7 wt% (on biomass basis, equivalent to 23.7 ± 2.2 wt% on paper sludge basis) and 23.8 ± 8.3 wt% (on biomass basis). Fast pyrolysis bio-liquid is a diluted aqueous containing various oxygenates (major, including alcohols, acids, benzenoid aromatics, aldehydes, ketones, ethers, and esters) and hydrocarbons. Liquid-liquid extraction of the fast pyrolysis bio-liquid using CH3OH/H2O and SO2/H2O was further performed to obtain an improved bio-liquid with relatively high concentration of the desired bio-based chemicals (namely benzenoid aromatics with the concentration of 53.1–65.9 area%). Both SO2/H2O and CH3OH/H2O show high liquid-liquid extraction efficiency to concentrate the benzenoid aromatics for 3.4–11.0 times. This work shows the fast pyrolysis followed by liquid-liquid extraction for the valorization of paper sludge, of which the former has been recently demonstrated on a pilot-scale unit in industry. However, the latter still needs to be further developed by, e.g., focusing on the extraction solvent and continuous liquid-liquid extraction process integrated to fast pyrolysis.
{"title":"Fast pyrolysis of paper sludge in a continuous stirred-tank reactor and liquid-liquid extraction of benzenoid aromatics from fast pyrolysis bio-liquid","authors":"","doi":"10.1016/j.renene.2024.121429","DOIUrl":"10.1016/j.renene.2024.121429","url":null,"abstract":"<div><div>Paper sludge is a solid waste in paper mills and is conventionally treated by, <em>e.g</em>., landfill, composting, and incineration. Paper sludge contains paper production fillers and lignocellulosic biomass, both of which can be recycled to recover circular minerals and produce bio-based fuels and chemicals by, <em>e.g</em>., thermochemical recycling technology namely fast pyrolysis, for circular bioeconomy. In this paper, three different paper sludge samples collected in The Netherlands and Spain were analyzed by thermogravimetric analysis, moisture analysis, ash analysis, CHNS elemental analysis, powder X-ray diffraction, and X-ray fluorescence spectrometry. Fast pyrolysis of paper sludge was carried out in a lab-scale continuous stirred tank reactor at 500 ± 10 °C with a paper sludge feeding rate of 1 kg h<sup>−1</sup>. The recovery of circular minerals, which are mainly calcium carbonate, is 87.1 ± 2.2 % (on mineral basis). The yields of fast pyrolysis bio-liquid and biochar are 49.2 ± 6.7 wt% (on biomass basis, equivalent to 23.7 ± 2.2 wt% on paper sludge basis) and 23.8 ± 8.3 wt% (on biomass basis). Fast pyrolysis bio-liquid is a diluted aqueous containing various oxygenates (major, including alcohols, acids, benzenoid aromatics, aldehydes, ketones, ethers, and esters) and hydrocarbons. Liquid-liquid extraction of the fast pyrolysis bio-liquid using CH<sub>3</sub>OH/H<sub>2</sub>O and SO<sub>2</sub>/H<sub>2</sub>O was further performed to obtain an improved bio-liquid with relatively high concentration of the desired bio-based chemicals (namely benzenoid aromatics with the concentration of 53.1–65.9 area%). Both SO<sub>2</sub>/H<sub>2</sub>O and CH<sub>3</sub>OH/H<sub>2</sub>O show high liquid-liquid extraction efficiency to concentrate the benzenoid aromatics for 3.4–11.0 times. This work shows the fast pyrolysis followed by liquid-liquid extraction for the valorization of paper sludge, of which the former has been recently demonstrated on a pilot-scale unit in industry. However, the latter still needs to be further developed by, <em>e.g</em>., focusing on the extraction solvent and continuous liquid-liquid extraction process integrated to fast pyrolysis.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.renene.2024.121401
In this study, a concentrated thermo-photovoltaic collector is examined experimentally and numerically, while it was geometrically optimized. The main objective is the collector's thermal performance evaluation and optical optimization for operation in Greece. Experiments were conducted in Athens, Greece, from July 10th to 17th, 2023, investigating the thermal operation of the collector in a temperature range of approximately 40–80 °C. The collector's slope was set to 12.3° for maximum solar irradiance utilization during the specified dates, considering south orientation. A numerical model was created using SolidWorks Flow Simulation and COMSOL Multiphysics, The model was validated with the experimental data, achieving mean deviation less than 6.5 % and a maximum deviation of 9.6 %. Various geometries were optically examined using Tonatiuh software. By applying a performance evaluation criterion, a new design is proposed and compared to the initial design across four different months, considering constant tilt angle. A maximum thermal efficiency of 49.19 % at the lower inlet temperature was found experimentally. The temperature of the PV cells was found to be highest where the solar rays are concentrated. Shape optimization revealed significant enhancements in optical efficiency, particularly at negative incident angles. The new geometry showed substantial improvement, with enhancements exceeding 20 % considering daily operation.
{"title":"Experimental analysis and optimization of a concentrated thermo-photovoltaic collector with bi-facial receiver","authors":"","doi":"10.1016/j.renene.2024.121401","DOIUrl":"10.1016/j.renene.2024.121401","url":null,"abstract":"<div><div>In this study, a concentrated thermo-photovoltaic collector is examined experimentally and numerically, while it was geometrically optimized. The main objective is the collector's thermal performance evaluation and optical optimization for operation in Greece. Experiments were conducted in Athens, Greece, from July 10th to 17th, 2023, investigating the thermal operation of the collector in a temperature range of approximately 40–80 °C. The collector's slope was set to 12.3° for maximum solar irradiance utilization during the specified dates, considering south orientation. A numerical model was created using SolidWorks Flow Simulation and COMSOL Multiphysics, The model was validated with the experimental data, achieving mean deviation less than 6.5 % and a maximum deviation of 9.6 %. Various geometries were optically examined using Tonatiuh software. By applying a performance evaluation criterion, a new design is proposed and compared to the initial design across four different months, considering constant tilt angle. A maximum thermal efficiency of 49.19 % at the lower inlet temperature was found experimentally. The temperature of the PV cells was found to be highest where the solar rays are concentrated. Shape optimization revealed significant enhancements in optical efficiency, particularly at negative incident angles. The new geometry showed substantial improvement, with enhancements exceeding 20 % considering daily operation.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":null,"pages":null},"PeriodicalIF":9.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}