Yuchao Yan, Ruomiao Yang, Zhen-tao Liu, Jinlong Liu
In the available literature, information on marine engines is limited for the general researcher. The goal of this study is to provide high quality information on a marine diesel engine that is beneficial to the engine community. Information on a 6L MAN L21/31 marine diesel engine is collected from existing studies and a three dimensional computational fluid dynamics model is built in this paper that can characterize the in-cylinder activities occurring in this marine engine. The good agreement between experimentally measured and model predicted cylinder pressure and heat release rate indicates a good calibration of the numerical model. Simulation results show that sufficient oxygen is still available in the chamber when the exhaust valve is open, suggesting the possibility of further reducing incomplete combustion products by increasing the utilization of excess air. Moreover, the model predictions help to show that the injection settings are already well calibrated for the rated power condition in terms of the balance between fuel economy and clean combustion. Accordingly, future efficiency improvements and emission reductions are suggested to be achieved by the optimization of the chamber shape, which has the potential to further improve the air utilization.
在现有的文献中，关于船用发动机的信息是有限的一般研究人员。本研究的目的是提供高质量的船用柴油机信息，有利于发动机界。本文收集了6L MAN L21/31船用柴油机的相关研究资料，建立了能够表征该船用柴油机缸内活动的三维计算流体动力学模型。实验测量值与模型预测值吻合较好，表明数值模型校正较好。模拟结果表明，当排气阀打开时，燃烧室内仍有足够的氧气，这表明通过增加多余空气的利用，可以进一步减少不完全燃烧产物。此外，模型预测有助于表明，在燃油经济性和清洁燃烧之间的平衡方面，喷射设置已经根据额定功率条件进行了很好的校准。因此，建议通过优化腔室形状来实现未来的效率提高和减排，这有可能进一步提高空气利用率。
{"title":"Three-Dimensional Computational Fluid Dynamics Modeling of the Combustion Process of a MAN L21/31 Marine Diesel Engine","authors":"Yuchao Yan, Ruomiao Yang, Zhen-tao Liu, Jinlong Liu","doi":"10.1115/imece2022-96089","DOIUrl":"https://doi.org/10.1115/imece2022-96089","url":null,"abstract":"\u0000 In the available literature, information on marine engines is limited for the general researcher. The goal of this study is to provide high quality information on a marine diesel engine that is beneficial to the engine community. Information on a 6L MAN L21/31 marine diesel engine is collected from existing studies and a three dimensional computational fluid dynamics model is built in this paper that can characterize the in-cylinder activities occurring in this marine engine. The good agreement between experimentally measured and model predicted cylinder pressure and heat release rate indicates a good calibration of the numerical model. Simulation results show that sufficient oxygen is still available in the chamber when the exhaust valve is open, suggesting the possibility of further reducing incomplete combustion products by increasing the utilization of excess air. Moreover, the model predictions help to show that the injection settings are already well calibrated for the rated power condition in terms of the balance between fuel economy and clean combustion. Accordingly, future efficiency improvements and emission reductions are suggested to be achieved by the optimization of the chamber shape, which has the potential to further improve the air utilization.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83227230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The growing energy demand and climate change emphasize the need to continuously use environmentally friendly energy sources. Consequently, renewable energy sources such as solar energy, which relies on the use of photovoltaic modules, have become popular in recent years. Photovoltaic (PV) modules convert the incident solar irradiance to electric energy. In such devices, by reducing the operating temperature, the associated solar energy conversion efficiency can be increased, and their lifetime extended. Accordingly, to compare their impact on the performance of PV modules, three different cooling methods, all of them coupled to a thermoelectric (TE) generator, (i) natural cooling, (ii) forced air cooling, and (iii) water cooling, are assessed. To evaluate the referred cooling methods, a computational model describing the behavior of the studied cooling methods is initially developed. Then, a PV model accurately predicting the behavior of commercial PV modules is developed and coupled to the cooling methods one. Finally, accounting for local ambient conditions and system operation over the course of one year, several simulations of PV modules with and without cooling systems are carried out using the developed tool. The main results indicate that some cooling techniques are adequate for some months of the year only, whereas the others do so for the remaining months. Indeed, PV module temperature reductions of up 7.7% and system efficiencies of up to 17.2% are observed. One of the particularities of this work relates to the use of local ambient conditions and system operation over a whole operating year.
{"title":"Assessment of Cooling Technologies for Solar Photovoltaic Panels Accounting for Local Solar Irradiance and Ambient Temperature Conditions","authors":"Marcelo Lucas Aguilar, Cesar Celis","doi":"10.1115/imece2022-90239","DOIUrl":"https://doi.org/10.1115/imece2022-90239","url":null,"abstract":"\u0000 The growing energy demand and climate change emphasize the need to continuously use environmentally friendly energy sources. Consequently, renewable energy sources such as solar energy, which relies on the use of photovoltaic modules, have become popular in recent years. Photovoltaic (PV) modules convert the incident solar irradiance to electric energy. In such devices, by reducing the operating temperature, the associated solar energy conversion efficiency can be increased, and their lifetime extended. Accordingly, to compare their impact on the performance of PV modules, three different cooling methods, all of them coupled to a thermoelectric (TE) generator, (i) natural cooling, (ii) forced air cooling, and (iii) water cooling, are assessed. To evaluate the referred cooling methods, a computational model describing the behavior of the studied cooling methods is initially developed. Then, a PV model accurately predicting the behavior of commercial PV modules is developed and coupled to the cooling methods one. Finally, accounting for local ambient conditions and system operation over the course of one year, several simulations of PV modules with and without cooling systems are carried out using the developed tool. The main results indicate that some cooling techniques are adequate for some months of the year only, whereas the others do so for the remaining months. Indeed, PV module temperature reductions of up 7.7% and system efficiencies of up to 17.2% are observed. One of the particularities of this work relates to the use of local ambient conditions and system operation over a whole operating year.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78060844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The challenges during the aftermath of natural disasters in remote locations, such as unreliable power supply from the grid during crucial times, coupled with ever-increasing energy needs, demand new and innovative solutions to limited energy production. Local, on-site power generation, such as combined cooling, heating, and power (CCHP) systems, may safeguard against grid fluctuations, outages, and provide additional security through grid independence. CCHP systems can provide more reliable and resilient energy supply to buildings and communities while also providing energy-efficient, cost-effective, and environmentally sustainable solutions compared to centralized power systems. Biomass-driven CCHP systems have been recognized as a potential technology to bring increased efficiency of fuel utilization and environmentally sustainable solutions. Biomass as an energy source is created through agricultural and forestry by-products and may thus be efficiently and conveniently transported to remote rural communities. This paper presents a design and implementation analysis of biomass (primarily wood pellets)-driven CCHP systems for a rural community across the United States. The U.S. Department of Energy Climate Regions map was used to determine areas of interest. For this study, all three climates moist, dry, and marine as well as all major climate zones (2–6) were included. To effectively compare small towns across the U.S., the selection process was based on certain criteria: A population of approximately 1,500 people, the existence of a rural hospital, two kinds of schools (E.g., an elementary and a high school), and small businesses. The following places meet those conditions and are located in differentiating climate zones: (2A) Keystone Heights, FL, (3A) Ackerman, MS, (3B) Quincy, CA, (3C) Mariposa, CA, (4A) Hardinsburg, KY, (4C) Coupeville, WA, (5A) Alma, NE, (5B) Lovelock, NV, (6A) Colebrook, NH, (6B) Choteau, MT. Each location was investigated based on the merits of on-site CCHP systems and potential grid independence. The viability of wood pellets (WP) as a suitable fuel source is explored by comparing it to a conventional natural gas-driven and grid-connected system. To measure viability, three performance parameters — operational cost (OC), primary energy consumption (PEC), and carbon dioxide emission (CDE) — are considered in the analysis. The results demonstrate that in many climate regions wood pellet-fueled CCHP systems create significant economic and environmental advantages over traditional systems. Additionally, on-site energy production and the potential for grid independence, especially in the aftermath of natural disasters provide critical services and added upsides of traditional systems. The main factors in increasing the viability of CCHP systems are the appropriate sizing and operational strategies of the system and the purchase price of biomass with respect to the price of traditional fuels.
{"title":"Multi-Regional Design and Analysis of Biomass-Driven Combined Cooling, Heating and Power Systems for Rural Communities","authors":"Philippe C. Schicker, Heejin Cho","doi":"10.1115/imece2022-96104","DOIUrl":"https://doi.org/10.1115/imece2022-96104","url":null,"abstract":"\u0000 The challenges during the aftermath of natural disasters in remote locations, such as unreliable power supply from the grid during crucial times, coupled with ever-increasing energy needs, demand new and innovative solutions to limited energy production. Local, on-site power generation, such as combined cooling, heating, and power (CCHP) systems, may safeguard against grid fluctuations, outages, and provide additional security through grid independence. CCHP systems can provide more reliable and resilient energy supply to buildings and communities while also providing energy-efficient, cost-effective, and environmentally sustainable solutions compared to centralized power systems. Biomass-driven CCHP systems have been recognized as a potential technology to bring increased efficiency of fuel utilization and environmentally sustainable solutions. Biomass as an energy source is created through agricultural and forestry by-products and may thus be efficiently and conveniently transported to remote rural communities. This paper presents a design and implementation analysis of biomass (primarily wood pellets)-driven CCHP systems for a rural community across the United States. The U.S. Department of Energy Climate Regions map was used to determine areas of interest. For this study, all three climates moist, dry, and marine as well as all major climate zones (2–6) were included. To effectively compare small towns across the U.S., the selection process was based on certain criteria: A population of approximately 1,500 people, the existence of a rural hospital, two kinds of schools (E.g., an elementary and a high school), and small businesses. The following places meet those conditions and are located in differentiating climate zones: (2A) Keystone Heights, FL, (3A) Ackerman, MS, (3B) Quincy, CA, (3C) Mariposa, CA, (4A) Hardinsburg, KY, (4C) Coupeville, WA, (5A) Alma, NE, (5B) Lovelock, NV, (6A) Colebrook, NH, (6B) Choteau, MT. Each location was investigated based on the merits of on-site CCHP systems and potential grid independence. The viability of wood pellets (WP) as a suitable fuel source is explored by comparing it to a conventional natural gas-driven and grid-connected system. To measure viability, three performance parameters — operational cost (OC), primary energy consumption (PEC), and carbon dioxide emission (CDE) — are considered in the analysis. The results demonstrate that in many climate regions wood pellet-fueled CCHP systems create significant economic and environmental advantages over traditional systems. Additionally, on-site energy production and the potential for grid independence, especially in the aftermath of natural disasters provide critical services and added upsides of traditional systems. The main factors in increasing the viability of CCHP systems are the appropriate sizing and operational strategies of the system and the purchase price of biomass with respect to the price of traditional fuels.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90541388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this research is to evaluate the feasibility and performance of a vertical ground source refrigeration system for cooling a typical 7300 m2 office building after replacing cooling towers used for condenser cooling with three different designs of ground heat exchangers. To that end, a three-dimensional, transient, and conjugated finite volume model is developed and simulated to compare the thermo-hydraulic performance of the traditional single U-tube with that of double U-shaped, and spiral-shaped ground heat exchangers at different flow rates. Based on the results, spiral shaped ground heat exchangers outperform other designs, as seen by better heat exchange rates between the fluid and the soil, which translates to a greater temperature reduction of the cooling water. This improvement not only allows for using smaller number of boreholes which saves the construction costs compared to other designs, but it also improves the coefficient of performance of the system by significantly lowering the cooling water temperature flowing back to the condenser when compared to the conventional cooling tower. This approach also eliminates cooling tower water consumption (saves about 14,500 L/day), tower noise, annual maintenance expenses, and costs for periodical cooling tower replacement. The presented findings make a significant contribution to society by offering innovative and sustainable solutions for cost reduction, environmental conservation, and energy efficiency.
{"title":"The Potential and Limitations of Using Geothermal-Sourced Chiller Plants to Eliminate Cooling Towers","authors":"A. Farag, Mahmoud A. Ahmed, S. Ookawara, M. Emam","doi":"10.1115/imece2022-96657","DOIUrl":"https://doi.org/10.1115/imece2022-96657","url":null,"abstract":"\u0000 The purpose of this research is to evaluate the feasibility and performance of a vertical ground source refrigeration system for cooling a typical 7300 m2 office building after replacing cooling towers used for condenser cooling with three different designs of ground heat exchangers. To that end, a three-dimensional, transient, and conjugated finite volume model is developed and simulated to compare the thermo-hydraulic performance of the traditional single U-tube with that of double U-shaped, and spiral-shaped ground heat exchangers at different flow rates. Based on the results, spiral shaped ground heat exchangers outperform other designs, as seen by better heat exchange rates between the fluid and the soil, which translates to a greater temperature reduction of the cooling water. This improvement not only allows for using smaller number of boreholes which saves the construction costs compared to other designs, but it also improves the coefficient of performance of the system by significantly lowering the cooling water temperature flowing back to the condenser when compared to the conventional cooling tower. This approach also eliminates cooling tower water consumption (saves about 14,500 L/day), tower noise, annual maintenance expenses, and costs for periodical cooling tower replacement. The presented findings make a significant contribution to society by offering innovative and sustainable solutions for cost reduction, environmental conservation, and energy efficiency.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77571473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Water supply is one of the imminent challenges in the coming age for mankind. The hydraulic ram pump is an eco-friendly and very cost-effective technology that can feasibly transport water from nearby water resources (such as lakes, streams, and rivers) to remote places for daily water needs. The goal of the present work was to investigate the effect of flapper valve size on pump performance. It was hypothesized that the decrease in the flapper valve size would impose more flow resistance at the waste-valve outlet diverting more water flow towards the ram pump inlet, which will increase the amount of water to the delivery tank. Based on the previous study, four flapper valve sizes (1-inch, 3/4-inch, 1/2-inch, and 1/4-inch) were selected for this study. Experiments with riser tubes were carried out using the selected flapper valve sizes. Results confirmed that the flapper valve size has a considerable influence on performance of the hydraulic ram pump. The 3/4-inch flapper valve displayed the maximum pump’s volumetric (21.7%) and energy (38.9%) efficiencies, followed by 1-inch, 1/4-inch, and 1/2-inch sized flapper valves. The flow capacity of the studied hydraulic ram pump system for 3/4-inch valve was found to be 1121 gal/day.
{"title":"Effect of Flapper Valve on the Performance of a Hydraulic Ram Pump","authors":"Ashokkumar M. Sharma, D. Banerjee, S. Pidugu","doi":"10.1115/imece2022-95901","DOIUrl":"https://doi.org/10.1115/imece2022-95901","url":null,"abstract":"\u0000 Water supply is one of the imminent challenges in the coming age for mankind. The hydraulic ram pump is an eco-friendly and very cost-effective technology that can feasibly transport water from nearby water resources (such as lakes, streams, and rivers) to remote places for daily water needs. The goal of the present work was to investigate the effect of flapper valve size on pump performance. It was hypothesized that the decrease in the flapper valve size would impose more flow resistance at the waste-valve outlet diverting more water flow towards the ram pump inlet, which will increase the amount of water to the delivery tank. Based on the previous study, four flapper valve sizes (1-inch, 3/4-inch, 1/2-inch, and 1/4-inch) were selected for this study. Experiments with riser tubes were carried out using the selected flapper valve sizes. Results confirmed that the flapper valve size has a considerable influence on performance of the hydraulic ram pump. The 3/4-inch flapper valve displayed the maximum pump’s volumetric (21.7%) and energy (38.9%) efficiencies, followed by 1-inch, 1/4-inch, and 1/2-inch sized flapper valves. The flow capacity of the studied hydraulic ram pump system for 3/4-inch valve was found to be 1121 gal/day.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81463686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
While the field of wave energy has been the subject of numerical simulation, scale model testing, and precommercial project testing for decades, wave energy technologies remain in the early stages of development and must continue to prove themselves as a promising modern renewable energy field. One of the difficulties that wave energy systems have been struggling to overcome is the design of highly efficient energy conversion systems that can convert the mechanical power derived from the oscillation of wave-activated bodies into another useful product. Often the power take-off (PTO) is defined as the single unit responsible for converting mechanical power into another usable form, such as electricity, pressurized fluid, compressed air, or others. The PTO — and the entire power conversion chain — is of great importance, as it not only affects how efficiently wave power is converted into electricity, but it also contributes to the mass, size, structural dynamics, and levelized cost of energy of the wave energy converter (WEC). Because there is no industrial standard device or devices for wave energy conversion in the marine energy industry, PTO system designs are highly variable. The majority of current WEC PTO systems incorporate a mechanical or hydraulic drive train, power generator, and an electrical control system. The challenge of WEC PTO designs is designing a mechanical-to-electrical component that can efficiently convert irregular, bidirectional, low-frequency, and low-alternating-velocity wave motions. While gross average power levels can be predicted in advance, the variable wave elevation input has to be converted into smooth electrical output and hence usually necessitates some type of energy storage system, such as battery storage, accumulators, super capacitors, etc., or other means of compensation such as an array of devices. One of the primary challenges for wave energy converter systems is the fluctuating nature of wave resources, which require WEC components to be designed to handle loads (i.e., torques, forces, and powers) that are many times greater than the average load. This approach requires a much greater PTO capacity than the average power output and often leads to a higher cost. In addition, supporting mechanical coupling and or gearing can be added to the power conversion chain to help alleviate difficulties with the transmission and control of fluctuating large loads with low frequencies (indicative of wave forcing) into smaller loads at higher frequencies (optimal for conventional electrical machine design). But these additions can quickly increase the complexity of the power conversion chain, which could result in a greater number of failure modes and increased maintenance costs; therefore, it is important to balance complexity and ruggedness. All of the previous points demonstrate how the PTO influences WEC dynamics, reliability, performance, and cost, which are critical design factors. This paper further explores t
{"title":"Review of Wave Energy Converter Power Take-Off Systems, Testing Practices, and Evaluation Metrics","authors":"Nathan Tom","doi":"10.1115/imece2022-94077","DOIUrl":"https://doi.org/10.1115/imece2022-94077","url":null,"abstract":"\u0000 While the field of wave energy has been the subject of numerical simulation, scale model testing, and precommercial project testing for decades, wave energy technologies remain in the early stages of development and must continue to prove themselves as a promising modern renewable energy field. One of the difficulties that wave energy systems have been struggling to overcome is the design of highly efficient energy conversion systems that can convert the mechanical power derived from the oscillation of wave-activated bodies into another useful product. Often the power take-off (PTO) is defined as the single unit responsible for converting mechanical power into another usable form, such as electricity, pressurized fluid, compressed air, or others. The PTO — and the entire power conversion chain — is of great importance, as it not only affects how efficiently wave power is converted into electricity, but it also contributes to the mass, size, structural dynamics, and levelized cost of energy of the wave energy converter (WEC). Because there is no industrial standard device or devices for wave energy conversion in the marine energy industry, PTO system designs are highly variable. The majority of current WEC PTO systems incorporate a mechanical or hydraulic drive train, power generator, and an electrical control system. The challenge of WEC PTO designs is designing a mechanical-to-electrical component that can efficiently convert irregular, bidirectional, low-frequency, and low-alternating-velocity wave motions. While gross average power levels can be predicted in advance, the variable wave elevation input has to be converted into smooth electrical output and hence usually necessitates some type of energy storage system, such as battery storage, accumulators, super capacitors, etc., or other means of compensation such as an array of devices. One of the primary challenges for wave energy converter systems is the fluctuating nature of wave resources, which require WEC components to be designed to handle loads (i.e., torques, forces, and powers) that are many times greater than the average load. This approach requires a much greater PTO capacity than the average power output and often leads to a higher cost. In addition, supporting mechanical coupling and or gearing can be added to the power conversion chain to help alleviate difficulties with the transmission and control of fluctuating large loads with low frequencies (indicative of wave forcing) into smaller loads at higher frequencies (optimal for conventional electrical machine design). But these additions can quickly increase the complexity of the power conversion chain, which could result in a greater number of failure modes and increased maintenance costs; therefore, it is important to balance complexity and ruggedness. All of the previous points demonstrate how the PTO influences WEC dynamics, reliability, performance, and cost, which are critical design factors. This paper further explores t","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89305662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Banerjee, I. Abu-Mahfouz, Jianyan Tian, A. E. Rahman
The need to accurately estimate wind power is essential to the design and deployment of individual wind turbines and wind farms. The estimation problem is framed as wind power curve modeling. Lately, machine learning techniques have been used to model power curves and provide power estimates. Such models rely on the fact that all outliers are removed from the raw wind data before they are used in modeling and estimation since outliers can adversely affect performance. However, generating outlier-free data is not always possible. Robust models and robust objective functions can be two effective ways to obtain accurate power curves in the presence of outliers. In this paper, a robust density-based clustering technique (DBSCAN) to first identify outliers in the dataset is proposed, followed by artificial neural network (ANN) models that are trained using the outlier-free data to obtain accurate power curve estimates. ANNs are trained using a range of optimization methods and are compared in this study. Preliminary results show the proposed method is superior to probabilistic models that use error-functions to generate accurate power curves and that the proposed hybrid model can generate more accurate power output estimations in the presence of outliers compared to deterministic models such as integrated curve fitting models that are known to be robust.
{"title":"A Robust Hybrid Machine Learning-Based Modeling Technique for Wind Power Production Estimates","authors":"A. Banerjee, I. Abu-Mahfouz, Jianyan Tian, A. E. Rahman","doi":"10.1115/imece2022-94173","DOIUrl":"https://doi.org/10.1115/imece2022-94173","url":null,"abstract":"\u0000 The need to accurately estimate wind power is essential to the design and deployment of individual wind turbines and wind farms. The estimation problem is framed as wind power curve modeling. Lately, machine learning techniques have been used to model power curves and provide power estimates. Such models rely on the fact that all outliers are removed from the raw wind data before they are used in modeling and estimation since outliers can adversely affect performance. However, generating outlier-free data is not always possible. Robust models and robust objective functions can be two effective ways to obtain accurate power curves in the presence of outliers. In this paper, a robust density-based clustering technique (DBSCAN) to first identify outliers in the dataset is proposed, followed by artificial neural network (ANN) models that are trained using the outlier-free data to obtain accurate power curve estimates. ANNs are trained using a range of optimization methods and are compared in this study. Preliminary results show the proposed method is superior to probabilistic models that use error-functions to generate accurate power curves and that the proposed hybrid model can generate more accurate power output estimations in the presence of outliers compared to deterministic models such as integrated curve fitting models that are known to be robust.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89387373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohiodin Nazemi, R. Unnþórsson, Christiaan Richter
Seaweed is a promising organic fuel source due to its rapid growth rates, efficiency as a carbon sink, and pH resistance. It is a potential renewable fuel source since it can be transformed into high-value fuel by using either thermochemical processes such as gasification, or anaerobic digestion. However, drying the seaweed is necessary to combust, pyrolyze, or gasify seaweed. In this study, we focus on the drying process. To address this, a biomass drying cabinet was designed, constructed, tested, and experimentally evaluated. During drying runs, the temperature inside the cabinet and the moisture content of seaweed were measured. The goal of this design was to reduce the moisture content of seaweed to the optimal range for gasification-between 15% to 20%. We demonstrate the drying of fresh seaweed with an initial moisture content of around 80% to as low as 12% after 22 hours. Bladderwrack is the type of seaweed that is used in this study. Based on the results of the tests, around 19 hours of drying is needed to reduce the moisture content of seaweed to the target range (15%–20%). In conclusion, moisture reduction in Bladderwrack seaweed was analyzed and the design of the seaweed drying cabinet was evaluated. Based on our results modifications to achieve more homogeneous drying throughout the cabinet are proposed.
{"title":"Analyzing the Process of Seaweed Drying in a Drying Cabinet","authors":"Mohiodin Nazemi, R. Unnþórsson, Christiaan Richter","doi":"10.1115/imece2022-94524","DOIUrl":"https://doi.org/10.1115/imece2022-94524","url":null,"abstract":"\u0000 Seaweed is a promising organic fuel source due to its rapid growth rates, efficiency as a carbon sink, and pH resistance. It is a potential renewable fuel source since it can be transformed into high-value fuel by using either thermochemical processes such as gasification, or anaerobic digestion. However, drying the seaweed is necessary to combust, pyrolyze, or gasify seaweed. In this study, we focus on the drying process. To address this, a biomass drying cabinet was designed, constructed, tested, and experimentally evaluated. During drying runs, the temperature inside the cabinet and the moisture content of seaweed were measured. The goal of this design was to reduce the moisture content of seaweed to the optimal range for gasification-between 15% to 20%. We demonstrate the drying of fresh seaweed with an initial moisture content of around 80% to as low as 12% after 22 hours. Bladderwrack is the type of seaweed that is used in this study. Based on the results of the tests, around 19 hours of drying is needed to reduce the moisture content of seaweed to the target range (15%–20%). In conclusion, moisture reduction in Bladderwrack seaweed was analyzed and the design of the seaweed drying cabinet was evaluated. Based on our results modifications to achieve more homogeneous drying throughout the cabinet are proposed.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"100 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91180578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Khan, Sambhaji T. Kadam, A. Kyriakides, Ibrahim Hassan, A. Papadopoulos, Mohammad Sohel Rahman, P. Seferlis
Most of the absorbent-refrigerant pairings are evaluated considering single-effect vapour absorption refrigeration (VAR) cycle. The coefficient of performance (COP) based modelling of VAR enables its quick performance evaluation. The development of efficient and environmentally benign fluid pairing is required to replace conventional refrigerants. Operating parameters-based COP models are scarce for single-effect VAR systems, and fewer correlations are available for the COP estimation. The paper compares five performance-based models reported in the literature for operating absorption cooling systems with various refrigerant and absorbent pairing. The comprehensive mean absolute percentage error (MAPE) analysis was performed for five reported correlations for more than 1601 data points of different fluid pairings. Results revealed that RMSD and MAPE values seem significantly higher for the reported correlations apart from the recently developed COP correlation accounted for fluid parameters in prediction. This indicates that the earlier reported correlations only accounted for the specific fluid pairing and could not incorporate different fluid pairing, which has been considered a recently reported correlation that resulted in the significantly improved prediction ability for COP. The finding from this study highlighted that the newly registered COP prediction correlation could be beneficial for developing new single-effect VAR cycles as it accounted for both the operating parameters and fluid parameters.
{"title":"Comparative Analysis of Coefficient of Performance (COP) Correlations of Single-Effect Vapor Absorption Refrigeration (VAR) Cycle","authors":"M. Khan, Sambhaji T. Kadam, A. Kyriakides, Ibrahim Hassan, A. Papadopoulos, Mohammad Sohel Rahman, P. Seferlis","doi":"10.1115/imece2022-93943","DOIUrl":"https://doi.org/10.1115/imece2022-93943","url":null,"abstract":"\u0000 Most of the absorbent-refrigerant pairings are evaluated considering single-effect vapour absorption refrigeration (VAR) cycle. The coefficient of performance (COP) based modelling of VAR enables its quick performance evaluation. The development of efficient and environmentally benign fluid pairing is required to replace conventional refrigerants. Operating parameters-based COP models are scarce for single-effect VAR systems, and fewer correlations are available for the COP estimation. The paper compares five performance-based models reported in the literature for operating absorption cooling systems with various refrigerant and absorbent pairing. The comprehensive mean absolute percentage error (MAPE) analysis was performed for five reported correlations for more than 1601 data points of different fluid pairings. Results revealed that RMSD and MAPE values seem significantly higher for the reported correlations apart from the recently developed COP correlation accounted for fluid parameters in prediction. This indicates that the earlier reported correlations only accounted for the specific fluid pairing and could not incorporate different fluid pairing, which has been considered a recently reported correlation that resulted in the significantly improved prediction ability for COP. The finding from this study highlighted that the newly registered COP prediction correlation could be beneficial for developing new single-effect VAR cycles as it accounted for both the operating parameters and fluid parameters.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88489393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing a viable data-driven policy for the management of electrical-energy consumption in campus residences is contingent on the proper knowledge of the electricity usage pattern and its predictability. In this study, an adaptive neuro-fuzzy inference systems (ANFIS) was developed to model the electrical energy consumption of students’ residence using the University of Johannesburg, South Africa as a case study. The model was developed based on the environmental conditions vis-à-vis meteorological parameters namely temperature, wind speed, and humidity of the respective days as the input variables while electricity consumption (kWh) was used as the output variable. The fuzzy c-means (FCM) is a type of clustering technique that is preferred owing to its speed boost capacity. The best FCM-clustered ANFIS-model based on a range of 2–10 clusters was selected after evaluating their performance using relevant statistical metrics namely; mean absolute percentage error (MAPE), root mean square error (RMSE), and mean absolute deviation (MAD). FCM-ANFIS with 7 clusters outperformed all other models with the least error and highest accuracy. The RMSE, MAPE, MAD, and R2-values of the best models are 0.043, 0.65, 1.051, and 0.9890 respectively. The developed model will assist in optimizing energy consumption and assist in designing and sizing alternative energy systems for campus residences.
{"title":"Prediction of Electrical Energy Consumption in University Campus Residence Using FCM-Clustered Neuro-Fuzzy Model","authors":"O. Adeleke, T. Jen","doi":"10.1115/imece2022-96793","DOIUrl":"https://doi.org/10.1115/imece2022-96793","url":null,"abstract":"\u0000 Developing a viable data-driven policy for the management of electrical-energy consumption in campus residences is contingent on the proper knowledge of the electricity usage pattern and its predictability. In this study, an adaptive neuro-fuzzy inference systems (ANFIS) was developed to model the electrical energy consumption of students’ residence using the University of Johannesburg, South Africa as a case study. The model was developed based on the environmental conditions vis-à-vis meteorological parameters namely temperature, wind speed, and humidity of the respective days as the input variables while electricity consumption (kWh) was used as the output variable. The fuzzy c-means (FCM) is a type of clustering technique that is preferred owing to its speed boost capacity. The best FCM-clustered ANFIS-model based on a range of 2–10 clusters was selected after evaluating their performance using relevant statistical metrics namely; mean absolute percentage error (MAPE), root mean square error (RMSE), and mean absolute deviation (MAD). FCM-ANFIS with 7 clusters outperformed all other models with the least error and highest accuracy. The RMSE, MAPE, MAD, and R2-values of the best models are 0.043, 0.65, 1.051, and 0.9890 respectively. The developed model will assist in optimizing energy consumption and assist in designing and sizing alternative energy systems for campus residences.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91365203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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