Hadi Mirian, M. Anbarsooz, Abbas Hoshyar, A. Arabgolarcheh
Yet, several locations for mounting the wind turbines in urban areas have been proposed, which can be categorized into four main groups; (a) on the rooftops, (b) between the buildings, (c) integrated into the buildings’ skin and (d) inside a though-building hole. Through-building holes take advantage of the pressure difference between the windward and leeward facades of the building to generate a high-speed velocity zone for mounting the wind turbine. In the current study, three-dimensional numerical simulations of atmospheric turbulent boundary layer flow around high-rise buildings are carried out to determine the optimum location and size of the duct. For this purpose, square cross-section buildings (20 × 20 m) with heights of H0 = 60, 120 and 180 m are considered. Numerical results showed that the difference of the pressure coefficient on the windward and leeward facades of the building without the hole can predict the best location for mounting the wind turbine with acceptable accuracy. Then, circular holes with various diameters of D = 2.5, 5.0, 7.5, 10 and 12.5m are created at z/H0 = 0.8, where the maximum pressure difference is close to the maximum. It is found that the maximum velocity increment occurs for D = 10 m and it is 31% greater than the U10 velocity of the incident wind profile. This means that the available wind power inside the duct is 2.25 times greater than the incident wind power.
{"title":"Through-Building Ducts for Mounting Wind Turbines: A Numerical Study","authors":"Hadi Mirian, M. Anbarsooz, Abbas Hoshyar, A. Arabgolarcheh","doi":"10.1115/power2021-64181","DOIUrl":"https://doi.org/10.1115/power2021-64181","url":null,"abstract":"\u0000 Yet, several locations for mounting the wind turbines in urban areas have been proposed, which can be categorized into four main groups; (a) on the rooftops, (b) between the buildings, (c) integrated into the buildings’ skin and (d) inside a though-building hole. Through-building holes take advantage of the pressure difference between the windward and leeward facades of the building to generate a high-speed velocity zone for mounting the wind turbine. In the current study, three-dimensional numerical simulations of atmospheric turbulent boundary layer flow around high-rise buildings are carried out to determine the optimum location and size of the duct. For this purpose, square cross-section buildings (20 × 20 m) with heights of H0 = 60, 120 and 180 m are considered. Numerical results showed that the difference of the pressure coefficient on the windward and leeward facades of the building without the hole can predict the best location for mounting the wind turbine with acceptable accuracy. Then, circular holes with various diameters of D = 2.5, 5.0, 7.5, 10 and 12.5m are created at z/H0 = 0.8, where the maximum pressure difference is close to the maximum. It is found that the maximum velocity increment occurs for D = 10 m and it is 31% greater than the U10 velocity of the incident wind profile. This means that the available wind power inside the duct is 2.25 times greater than the incident wind power.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87970391","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}
Rong Gao, Hao Sun, Limin Wang, Yufan Bu, Chao Wang, D. Che
With the application of selective catalytic reduction (SCR) technology, the operation of rotary air preheaters is faced with a challenge, the fouling problem caused by ammonium bisulfate (ABS). In previous studies, within the operational temperature range of the preheater, the gaseous ammonia and sulfur trioxide (or H2SO4) in the flue gas can react to form ABS and ammonium sulfate (AS). The initial condensation temperature of ABS might be over predicted due to the effect of the formation of AS, which has a higher initial formation temperature than ABS. In this study, the effects of the deposition temperature, ammonia-sulfur molar ratio and molar product of inlet flue gas on the deposition characteristics of inducing ash deposition compounds were experimentally studied to provide guidance to prevent fouling and corrosion of rotary air preheaters. The results show that the main path to generate ABS is the reaction between H2SO4 and NH3. With the increase in the deposition temperature, the contents of NH4+ and SO42− in the sediments decrease continuously, and the proportion of AS deposition increases. On the contrary, with temperature decreasing, more ABS is deposited. When the molar ratio of ammo-sulfur in the inlet flue gas increases, the proportion of AS in the sediments increases, and the deposition rate also gradually increases. When the ammo-sulfur product in the inlet flue gas increases, the concentrations of both NH4+ and SO42− in the sediments increased in a nearly consistent trend. The variations of the ratio and deposition rates of the two ions in the sediments were not obvious. The ratio of NH4+ and SO42− remains at about 1.2, and the sediment is mainly ABS.
{"title":"Experimental Investigation of Ammonia and Sulfur Deposition Characteristics in Rotary Air Preheater","authors":"Rong Gao, Hao Sun, Limin Wang, Yufan Bu, Chao Wang, D. Che","doi":"10.1115/power2021-65660","DOIUrl":"https://doi.org/10.1115/power2021-65660","url":null,"abstract":"\u0000 With the application of selective catalytic reduction (SCR) technology, the operation of rotary air preheaters is faced with a challenge, the fouling problem caused by ammonium bisulfate (ABS). In previous studies, within the operational temperature range of the preheater, the gaseous ammonia and sulfur trioxide (or H2SO4) in the flue gas can react to form ABS and ammonium sulfate (AS). The initial condensation temperature of ABS might be over predicted due to the effect of the formation of AS, which has a higher initial formation temperature than ABS. In this study, the effects of the deposition temperature, ammonia-sulfur molar ratio and molar product of inlet flue gas on the deposition characteristics of inducing ash deposition compounds were experimentally studied to provide guidance to prevent fouling and corrosion of rotary air preheaters. The results show that the main path to generate ABS is the reaction between H2SO4 and NH3. With the increase in the deposition temperature, the contents of NH4+ and SO42− in the sediments decrease continuously, and the proportion of AS deposition increases. On the contrary, with temperature decreasing, more ABS is deposited. When the molar ratio of ammo-sulfur in the inlet flue gas increases, the proportion of AS in the sediments increases, and the deposition rate also gradually increases. When the ammo-sulfur product in the inlet flue gas increases, the concentrations of both NH4+ and SO42− in the sediments increased in a nearly consistent trend. The variations of the ratio and deposition rates of the two ions in the sediments were not obvious. The ratio of NH4+ and SO42− remains at about 1.2, and the sediment is mainly ABS.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88073546","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}
Anuj Kumar, R. Kothari, S. Sahu, S. I. Kundalwal, A.K. Sharma
In recent years phase change materials (PCMs) have emerged as a promising material for various thermal management applications. However, the lower thermal conductivity of PCM is a major hindrance in its widespread use. In the present study, an experimental investigation is carried out using high thermal conductive carbon foam (CF) embedded with PCM inside heat sink for thermal management of electronic components. Various configurations of heat sinks such as unfinned heat sink without PCM, unfinned heat sink integrated with PCM, unfinned heat sink integrated with CF-PCM composite, two finned heat sink integrated with PCM, and two finned heat sink integrated with CF-PCM composite are investigated. The vacuum impregnation technique is employed to infiltrate the PCM inside the CF. Heat flux is varied in the range of 1.5 to 2.5 kW/m2. Temperature variation of the heat sink base is used to compare the performance of various heat sinks. Unfinned heat sink without and with PCM is used for baseline comparison. Enhancement ratios are presented for various set point temperatures (SPT) such as 65 and 75°C. The highest enhancement ratio of 4.98 is obtained for two fin CF-PCM composite heat sink.
{"title":"Investigation of Phase Change Material Integrated With High Thermal Conductive Carbon Foam Inside Heat Sinks for Thermal Management of Electronic Components","authors":"Anuj Kumar, R. Kothari, S. Sahu, S. I. Kundalwal, A.K. Sharma","doi":"10.1115/power2021-65569","DOIUrl":"https://doi.org/10.1115/power2021-65569","url":null,"abstract":"\u0000 In recent years phase change materials (PCMs) have emerged as a promising material for various thermal management applications. However, the lower thermal conductivity of PCM is a major hindrance in its widespread use. In the present study, an experimental investigation is carried out using high thermal conductive carbon foam (CF) embedded with PCM inside heat sink for thermal management of electronic components. Various configurations of heat sinks such as unfinned heat sink without PCM, unfinned heat sink integrated with PCM, unfinned heat sink integrated with CF-PCM composite, two finned heat sink integrated with PCM, and two finned heat sink integrated with CF-PCM composite are investigated. The vacuum impregnation technique is employed to infiltrate the PCM inside the CF. Heat flux is varied in the range of 1.5 to 2.5 kW/m2. Temperature variation of the heat sink base is used to compare the performance of various heat sinks. Unfinned heat sink without and with PCM is used for baseline comparison. Enhancement ratios are presented for various set point temperatures (SPT) such as 65 and 75°C. The highest enhancement ratio of 4.98 is obtained for two fin CF-PCM composite heat sink.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88913291","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}
Knowledge of wind energy harvesting is an ever-growing process, and to meet the enormous energy demand, wind farms shall have a significant role. An efficient wind farm is required to have an in-depth knowledge of turbine wake characteristics. This article presents an experimental investigation of the wake expansion process defined by the transition of wake from near to far wake regimes. The study has been performed on models horizontal axis wind turbine (HAWT) composed of NACA 0012 profile, keeping the ratio of root chord to tip chord length is 5:2. A constant temperature hot-wire anemometer (HWA) has been used to examine the rotor’s fluctuating flow field. The subsequent time-averaged normalizes velocity deficit, and vortex shedding frequency are used for the flow characteristics. Time-averaged velocity deficit measurement suggests a drop in upstream velocity by 20–30% within the vicinity of rotor tip downstream of the rotor plane. The study shows that flow recovery is initiating from the near wake regime around 1.08R. Further, the spectral findings indicates the low frequency dominance within 4R (R being the rotor radius), and the Strouhal number falls close to 0.23. The present wind tunnel study on wake characteristics throws significant insight into further enhancing the WT wake modeling.
{"title":"Characterizing the Transitional Behavior of Wind Turbine Wake From Near to Far Wake Regimes","authors":"Ravi Kumar, Ojing Siram, N. Sahoo, U. Saha","doi":"10.1115/power2021-65959","DOIUrl":"https://doi.org/10.1115/power2021-65959","url":null,"abstract":"\u0000 Knowledge of wind energy harvesting is an ever-growing process, and to meet the enormous energy demand, wind farms shall have a significant role. An efficient wind farm is required to have an in-depth knowledge of turbine wake characteristics. This article presents an experimental investigation of the wake expansion process defined by the transition of wake from near to far wake regimes. The study has been performed on models horizontal axis wind turbine (HAWT) composed of NACA 0012 profile, keeping the ratio of root chord to tip chord length is 5:2. A constant temperature hot-wire anemometer (HWA) has been used to examine the rotor’s fluctuating flow field. The subsequent time-averaged normalizes velocity deficit, and vortex shedding frequency are used for the flow characteristics. Time-averaged velocity deficit measurement suggests a drop in upstream velocity by 20–30% within the vicinity of rotor tip downstream of the rotor plane. The study shows that flow recovery is initiating from the near wake regime around 1.08R. Further, the spectral findings indicates the low frequency dominance within 4R (R being the rotor radius), and the Strouhal number falls close to 0.23. The present wind tunnel study on wake characteristics throws significant insight into further enhancing the WT wake modeling.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76538204","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}
Gas turbine engines with pulse detonation combustion show the superior performance in terms of specific work output and thermal efficiency when compared to the conventional gas turbine engines with isobaric combustion. But, a quasi-steady expansion of detonation products through the gas turbine results in an unsteady operation. Moreover, as the detonation products during quasi-steady expansion are initially at a very high temperature (over 2500 K), they cannot be expanded in the turbine as it is. To overcome the above difficulties associated with pulse detonation combustion in gas turbine engines, Air-Argon-Steam or organic fluid Combined Cycle (AASCC) is proposed in the present work. AASCC comprises two gas turbine cycles, viz. the Humphrey cycle with the air as the working fluid and the Brayton cycle with the argon as the working fluid and a steam turbine cycle, viz. the Rankine or organic Rankine cycle with the steam or organic substance as the working fluid. The temperature of the hot detonation products is reduced to Turbine Inlet Temperature (TIT) by exchanging heat energy between detonation products and compressed argon in a Detonation Products to Argon Heat Exchanger (DPAHE) and in turn, raising the temperature of the compressed argon to Argon Turbine Inlet Temperature (ATIT). The residual energy of both detonation products and argon after the expansion in the respective turbines is utilized to generate the steam or organic fluid vapor in the Heat Recovery Generators (HRGs) to operate a steam or organic fluid turbine. AASCC with pulse detonation combustion is analyzed based on quasi-steady state one dimensional formulation, and a computer code is developed in MATLAB to simulate the cycle performance at different compressor pressure ratios and TITs. C2H4/air is taken as the fuel-oxidizer. The performance of AASCC with pulse detonation combustion is compared with that of a conventional Air-Steam Combined Cycle (ASCC) with constant pressure combustion. It is found that the thermal efficiency of AASCC with pulse detonation combustion can go up to 44.5%–46.5% depending on the working fluid used in the bottoming Rankine cycle as against 37.8%–41.0% of ASCC at a TIT of 1400 K. The maximum specific work output of AASCC at a TIT of 1400 K is found to vary from 1143.0 to 1202.0 kJ/kg air as against to 335.0 to 364.0 kJ/kg air of ASCC.
{"title":"Air-Argon-Steam or Organic Fluid Combined Power Cycle With Pulse Detonation Combustion for Electric Power Plants","authors":"Pereddy Nageswara Reddy","doi":"10.1115/power2021-64141","DOIUrl":"https://doi.org/10.1115/power2021-64141","url":null,"abstract":"\u0000 Gas turbine engines with pulse detonation combustion show the superior performance in terms of specific work output and thermal efficiency when compared to the conventional gas turbine engines with isobaric combustion. But, a quasi-steady expansion of detonation products through the gas turbine results in an unsteady operation. Moreover, as the detonation products during quasi-steady expansion are initially at a very high temperature (over 2500 K), they cannot be expanded in the turbine as it is. To overcome the above difficulties associated with pulse detonation combustion in gas turbine engines, Air-Argon-Steam or organic fluid Combined Cycle (AASCC) is proposed in the present work. AASCC comprises two gas turbine cycles, viz. the Humphrey cycle with the air as the working fluid and the Brayton cycle with the argon as the working fluid and a steam turbine cycle, viz. the Rankine or organic Rankine cycle with the steam or organic substance as the working fluid. The temperature of the hot detonation products is reduced to Turbine Inlet Temperature (TIT) by exchanging heat energy between detonation products and compressed argon in a Detonation Products to Argon Heat Exchanger (DPAHE) and in turn, raising the temperature of the compressed argon to Argon Turbine Inlet Temperature (ATIT). The residual energy of both detonation products and argon after the expansion in the respective turbines is utilized to generate the steam or organic fluid vapor in the Heat Recovery Generators (HRGs) to operate a steam or organic fluid turbine. AASCC with pulse detonation combustion is analyzed based on quasi-steady state one dimensional formulation, and a computer code is developed in MATLAB to simulate the cycle performance at different compressor pressure ratios and TITs. C2H4/air is taken as the fuel-oxidizer. The performance of AASCC with pulse detonation combustion is compared with that of a conventional Air-Steam Combined Cycle (ASCC) with constant pressure combustion. It is found that the thermal efficiency of AASCC with pulse detonation combustion can go up to 44.5%–46.5% depending on the working fluid used in the bottoming Rankine cycle as against 37.8%–41.0% of ASCC at a TIT of 1400 K. The maximum specific work output of AASCC at a TIT of 1400 K is found to vary from 1143.0 to 1202.0 kJ/kg air as against to 335.0 to 364.0 kJ/kg air of ASCC.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81940558","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}
Coal use for generation of electricity is used extensively world-wide accounting for 40% of total power generation. Even with reductions in use over the last 10 years, coal still accounts for 20% of total electrical generation in the United States. An often-overlooked aspect of Pulverized Coal (PC) combustion is the erosion and abrasion of the coal injection nozzles. Currently there are over 300 active PC boilers in the US and over 1000 worldwide, with each boiler having 20–40 high alloy cast injectors. Due to the high velocity of PC injection and associated elevated rates of metal loss, these nozzles require constant replacement. Replacement and costs associated with loss of revenue, required scaffolding and casting can be a significant part of Operation and Maintenance (O&M) of a PC boiler. In addition to the constant requirement for thousands of replacement injection nozzles every year, combustion performance, NOx reduction, carbon conversion and general boiler efficiency will be impacted by hardware that is out of specification, if not replaced in a “timely” manner. Significant research in the 1980’s [1] provided some insight into the loss-of-metal process during PC injection, but limitations of existing hardware and software prevented more than an empirical methodology to be developed. In parallel with the literature work and research specifically for PC coal erosion rates, generalized efforts were employed and reported [6–9]. Meng [4] summarized model development for solid particles transported by a liquid or gas as highly empirical with little commonality between the models developed by the various researchers. Meng also made specific recommendations for less empiricism in model development methodology. Although there are several state-of-the-art empirical models [6, 8 & 9] more recently, semi-mechanistic models have been developed to predict solid particle erosion (e.g. Arabnejad et al., [17]) and have been successfully applied to sand erosion and abrasion in pipelines. In the current study, this method is being applied to PC injection nozzles coupled to detailed computational fluid dynamics (CFD) simulations. The intent is to quantify nozzle material loss rates, due to impacting coal particles, as a function of geometry, local velocities, and coal properties. The method used is utilizing CFD to model flow of particles and their impingement velocity with the PC nozzles. Then erosion models that are a function of impingement speed, angle, frequency and materials properties to examine erosion rates. The insight gained from the modeling will allow improved nozzle design, increased duty life, more cost-effective supply, and elevated injection velocity. In particular, low NOx coal combustion can be critically dependent on utilization of elevated injection velocities, which previous empirical models discourage. This paper reports on the application of the erosion equations and methods developed at the Erosion/Corrosion Research Center of T
{"title":"Application of a Mechanistic Erosion and Abrasion Model to Pulverized Coal (PC) Injections","authors":"L. Berg, S. Karimi, S. Shirazi","doi":"10.1115/power2021-63620","DOIUrl":"https://doi.org/10.1115/power2021-63620","url":null,"abstract":"\u0000 Coal use for generation of electricity is used extensively world-wide accounting for 40% of total power generation. Even with reductions in use over the last 10 years, coal still accounts for 20% of total electrical generation in the United States. An often-overlooked aspect of Pulverized Coal (PC) combustion is the erosion and abrasion of the coal injection nozzles. Currently there are over 300 active PC boilers in the US and over 1000 worldwide, with each boiler having 20–40 high alloy cast injectors. Due to the high velocity of PC injection and associated elevated rates of metal loss, these nozzles require constant replacement. Replacement and costs associated with loss of revenue, required scaffolding and casting can be a significant part of Operation and Maintenance (O&M) of a PC boiler. In addition to the constant requirement for thousands of replacement injection nozzles every year, combustion performance, NOx reduction, carbon conversion and general boiler efficiency will be impacted by hardware that is out of specification, if not replaced in a “timely” manner.\u0000 Significant research in the 1980’s [1] provided some insight into the loss-of-metal process during PC injection, but limitations of existing hardware and software prevented more than an empirical methodology to be developed. In parallel with the literature work and research specifically for PC coal erosion rates, generalized efforts were employed and reported [6–9]. Meng [4] summarized model development for solid particles transported by a liquid or gas as highly empirical with little commonality between the models developed by the various researchers. Meng also made specific recommendations for less empiricism in model development methodology.\u0000 Although there are several state-of-the-art empirical models [6, 8 & 9] more recently, semi-mechanistic models have been developed to predict solid particle erosion (e.g. Arabnejad et al., [17]) and have been successfully applied to sand erosion and abrasion in pipelines. In the current study, this method is being applied to PC injection nozzles coupled to detailed computational fluid dynamics (CFD) simulations. The intent is to quantify nozzle material loss rates, due to impacting coal particles, as a function of geometry, local velocities, and coal properties. The method used is utilizing CFD to model flow of particles and their impingement velocity with the PC nozzles. Then erosion models that are a function of impingement speed, angle, frequency and materials properties to examine erosion rates. The insight gained from the modeling will allow improved nozzle design, increased duty life, more cost-effective supply, and elevated injection velocity. In particular, low NOx coal combustion can be critically dependent on utilization of elevated injection velocities, which previous empirical models discourage.\u0000 This paper reports on the application of the erosion equations and methods developed at the Erosion/Corrosion Research Center of T","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81124439","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 United Nations World Water Development Report claims that more than 6 billion people will suffer from clean water shortage by 2050. This is a result of climate change, demand increase for water, increase of water pollution, increasing population, and reduction of water resources [1]. In order to delay / prevent water scarcity, humans must take action using less water or perhaps recovering wastewater. Aerobic digestion is one of the best common methods to treat wastewater; however, this technology requires heavily on the use of electric motors and is estimated to consume 2–3% of US electricity. In this paper, a multigeneration energy system is developed to treat wastewater using a net-zero energy building model. This system consists of four major sub-systems: an aerobic digester, an anaerobic digester, a Brayton cycle, and a Rankine cycle. Using anaerobic digestion to produce bio-fuels, which can then be used on-site to power aeration systems, may offer significant advantages to reduce electricity usage. This study shows that the required energy for a sample aeration case study process can be supplied by a multigeneration system. Parametric analyses are performed to show how system efficiency may be increased as well as to investigate the required oxygen and power for an activated sludge process in a wastewater treatment plant. It is found here that the proposed CHP system can produce 6 times more energy than the required energy for the aeration in the activated sludge process.
{"title":"Analysis of a Multigeneration Energy System for Wastewater Treatment","authors":"Mustafa Erguvan, David W. MacPhee","doi":"10.1115/power2021-65516","DOIUrl":"https://doi.org/10.1115/power2021-65516","url":null,"abstract":"\u0000 The United Nations World Water Development Report claims that more than 6 billion people will suffer from clean water shortage by 2050. This is a result of climate change, demand increase for water, increase of water pollution, increasing population, and reduction of water resources [1]. In order to delay / prevent water scarcity, humans must take action using less water or perhaps recovering wastewater. Aerobic digestion is one of the best common methods to treat wastewater; however, this technology requires heavily on the use of electric motors and is estimated to consume 2–3% of US electricity. In this paper, a multigeneration energy system is developed to treat wastewater using a net-zero energy building model. This system consists of four major sub-systems: an aerobic digester, an anaerobic digester, a Brayton cycle, and a Rankine cycle. Using anaerobic digestion to produce bio-fuels, which can then be used on-site to power aeration systems, may offer significant advantages to reduce electricity usage. This study shows that the required energy for a sample aeration case study process can be supplied by a multigeneration system. Parametric analyses are performed to show how system efficiency may be increased as well as to investigate the required oxygen and power for an activated sludge process in a wastewater treatment plant. It is found here that the proposed CHP system can produce 6 times more energy than the required energy for the aeration in the activated sludge process.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80679533","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}
This work aims to determine the optimal heat sink fin shape to promote the efficient rise of hot air away from the heat sink. The heat transfer and convective flow dynamics external to a commercial Stirling engine are investigated. In particular, this study employs an adjoint optimization approach based on CFD simulations to determine the sensitivity of the objective function to the shape of the heat sink and influence on the natural convection heat flow away from the external heat sink. This deterministic optimization approach increases the heat transfer rate of the heat sink by nearly 20% in this study when performing a small number of design iterations.
{"title":"Adjoint Optimization of Heat Transfer Within a Stirling Engine","authors":"A. DiCarlo, R. A. Caldwell","doi":"10.1115/power2021-65804","DOIUrl":"https://doi.org/10.1115/power2021-65804","url":null,"abstract":"\u0000 This work aims to determine the optimal heat sink fin shape to promote the efficient rise of hot air away from the heat sink. The heat transfer and convective flow dynamics external to a commercial Stirling engine are investigated. In particular, this study employs an adjoint optimization approach based on CFD simulations to determine the sensitivity of the objective function to the shape of the heat sink and influence on the natural convection heat flow away from the external heat sink. This deterministic optimization approach increases the heat transfer rate of the heat sink by nearly 20% in this study when performing a small number of design iterations.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76716300","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}
Accurate fault diagnosis of complex energy systems, such as wind turbines, is essential to avoid catastrophic accidents and ensure a stable power source. However, accurate fault diagnoses under dynamic operating conditions and various failure mechanisms are major challenges for wind turbines nowadays. Here we present a CapsNet-based deep learning scheme for data-driven fault diagnosis used in a digital twin of a wind turbine gearbox. The CapsNet model can extract the multi-dimensional features and rich spatial information from the gearbox monitoring data by an artificial neural network named the CapsNet. Through the dynamic routing algorithm between capsules, the network structure and parameters of the CapsNet model can be adjusted effectively to realize an accurate and robust classification of the operational conditions of a wind turbine gearbox, including front box stuck (single fault) and high-speed shaft bearing damage & planetary gear damage (coupling faults). Two gearbox datasets are used to verify the performance of the CapsNet model. The experimental results show that the accuracy of this proposed method is up to 98%, which proves the accuracy of CapsNet model in the case study when this model performed three-state classification (health, stuck, and coupled damage). Compared with state-of-the-art fault diagnosis methods reported in the literature, the CapsNet model has a competitive advantage, especially in the ability to diagnose coupling faults, high-speed shaft bearing damage & planetary gear damage in our case study. CapsNet has at least 2.4 percentage points higher than any other measure in our experiment. In addition, the proposed method can automatically extract features from the original monitoring data, and do not rely on expert experience or signal processing related knowledge, which provides a new avenue for constructing an accurate and efficient digital twin of wind turbine gearboxes.
{"title":"A CapsNet-Based Fault Diagnosis Method for a Digital Twin of a Wind Turbine Gearbox","authors":"Hao Zhao, Weifei Hu, Zhen-yu Liu, Jianrong Tan","doi":"10.1115/power2021-66029","DOIUrl":"https://doi.org/10.1115/power2021-66029","url":null,"abstract":"\u0000 Accurate fault diagnosis of complex energy systems, such as wind turbines, is essential to avoid catastrophic accidents and ensure a stable power source. However, accurate fault diagnoses under dynamic operating conditions and various failure mechanisms are major challenges for wind turbines nowadays. Here we present a CapsNet-based deep learning scheme for data-driven fault diagnosis used in a digital twin of a wind turbine gearbox. The CapsNet model can extract the multi-dimensional features and rich spatial information from the gearbox monitoring data by an artificial neural network named the CapsNet. Through the dynamic routing algorithm between capsules, the network structure and parameters of the CapsNet model can be adjusted effectively to realize an accurate and robust classification of the operational conditions of a wind turbine gearbox, including front box stuck (single fault) and high-speed shaft bearing damage & planetary gear damage (coupling faults). Two gearbox datasets are used to verify the performance of the CapsNet model. The experimental results show that the accuracy of this proposed method is up to 98%, which proves the accuracy of CapsNet model in the case study when this model performed three-state classification (health, stuck, and coupled damage). Compared with state-of-the-art fault diagnosis methods reported in the literature, the CapsNet model has a competitive advantage, especially in the ability to diagnose coupling faults, high-speed shaft bearing damage & planetary gear damage in our case study. CapsNet has at least 2.4 percentage points higher than any other measure in our experiment. In addition, the proposed method can automatically extract features from the original monitoring data, and do not rely on expert experience or signal processing related knowledge, which provides a new avenue for constructing an accurate and efficient digital twin of wind turbine gearboxes.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84605934","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}
Global warming concerns have pushed coal-fired power plants to develop innovative solutions which reduce CO2 emissions by increasing efficiency. While new ultra-supercritical units are built with extremely high efficiency, with Pingshan II approaching 50% LHV[1], subcritical units with much lower efficiency are a major source of installed capacity. The typical annual average net efficiency of subcritical units in China is about 37% LHV, and some are lower than 35% LHV. Since the total subcritical capacity in China is about 350GW and accounts for over one third of its total coal-fired power capacity, shutting all subcritical units down is not practical. Finding existing coal-fired plants a cost-effective solution which successfully combines advanced flexibility with high efficiency and low emissions, all while extending service lives, has challenged energy engineers worldwide. However, the (now proven) benefits a high temperature upgrade offers, compared to new construction options, made this an achievement worth pursuing. After many years of substantial incremental improvements to best-in-class technology, this first-of-its-kind subcritical high temperature retrofit successfully proves that a technically and economically feasible solution exists. It increases the main and reheat steam temperatures from 538°C (1000°F) to 600°C (1112°F), and the plant cycle and turbine internal efficiencies are greatly improved. This upgrade’s greatest efficiency gains occur at low loads, which is important as fossil plants respond to renewable energy’s increased grid contributions. These are combined with best-in-class flexibility, energy-savings, and technological advances, i.e., flue gas heat recovery technology and generalized regeneration technologies [4]. This project, the world’s first high-temperature subcritical coal-fired power plant retrofit, was initiated in April 2017 and finished in August 2019. Performance reports created by Siemens and GE record unit net efficiency at rated conditions improved from 38.6% to 43.5% LHV. The boiler’s lowest stable combustion load with operational SCR, without oil-firing support, was reduced from 55% to 19%. Substitution or upgrading of high-temperature components extended the lifetime of the unit by more than 30 years. At a third of the cost of new construction, this project set a high-water-mark for retrofitting subcritical units, and meets or supports the requisite attributes for Coal FIRST, Coal Plant of the Future, proposed by the United States Department of Energy (DOE) in 2019 [2].
{"title":"The Introduction and Analysis of the World’s First High-Temperature Retrofit Project on a Subcritical Coal-Fired Power Unit","authors":"Weizhong Feng, Li. Li","doi":"10.1115/power2021-65650","DOIUrl":"https://doi.org/10.1115/power2021-65650","url":null,"abstract":"\u0000 Global warming concerns have pushed coal-fired power plants to develop innovative solutions which reduce CO2 emissions by increasing efficiency. While new ultra-supercritical units are built with extremely high efficiency, with Pingshan II approaching 50% LHV[1], subcritical units with much lower efficiency are a major source of installed capacity.\u0000 The typical annual average net efficiency of subcritical units in China is about 37% LHV, and some are lower than 35% LHV. Since the total subcritical capacity in China is about 350GW and accounts for over one third of its total coal-fired power capacity, shutting all subcritical units down is not practical.\u0000 Finding existing coal-fired plants a cost-effective solution which successfully combines advanced flexibility with high efficiency and low emissions, all while extending service lives, has challenged energy engineers worldwide. However, the (now proven) benefits a high temperature upgrade offers, compared to new construction options, made this an achievement worth pursuing.\u0000 After many years of substantial incremental improvements to best-in-class technology, this first-of-its-kind subcritical high temperature retrofit successfully proves that a technically and economically feasible solution exists. It increases the main and reheat steam temperatures from 538°C (1000°F) to 600°C (1112°F), and the plant cycle and turbine internal efficiencies are greatly improved.\u0000 This upgrade’s greatest efficiency gains occur at low loads, which is important as fossil plants respond to renewable energy’s increased grid contributions. These are combined with best-in-class flexibility, energy-savings, and technological advances, i.e., flue gas heat recovery technology and generalized regeneration technologies [4].\u0000 This project, the world’s first high-temperature subcritical coal-fired power plant retrofit, was initiated in April 2017 and finished in August 2019. Performance reports created by Siemens and GE record unit net efficiency at rated conditions improved from 38.6% to 43.5% LHV. The boiler’s lowest stable combustion load with operational SCR, without oil-firing support, was reduced from 55% to 19%. Substitution or upgrading of high-temperature components extended the lifetime of the unit by more than 30 years. At a third of the cost of new construction, this project set a high-water-mark for retrofitting subcritical units, and meets or supports the requisite attributes for Coal FIRST, Coal Plant of the Future, proposed by the United States Department of Energy (DOE) in 2019 [2].","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85757178","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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