This paper presents an optimization algorithm based on the Artificial Neural Network (ANN) to determine the optimal shape, size, and density for the cylindrical flap of the Bottom-Hinged Oscillating Wave Surge Converter (BH-OWSC) that can extract maximal wave power under a given wave condition. Eight parameters are selected, and their upper and lower bounds are set at the initial stage, and then 64 cases with different combinatorial parametric settings are generated by the Design of Experiment process. The 64 cases are then fed into FLOW-3D to simulate the operations of the BH-OWSC under the given wave condition for calculating the capture factor, establishing a database for subsequent ANN data training purpose. To search the maximal capture factor in the specific range of the flap models, we fed 107 random models with various levels of design parameters into the ANN model, which adopts the backpropagation architecture and one hidden layer with ten neuron cells. After three complete random searches, and by simulating the ANN-derived flap’s geometry using FLOW-3D, the result shows that a maximal capture factor of 1.824 can be obtained. The major geometric features of the flap with maximal capture factor are (1) the cylinder axis of the flap inclines to the opposite direction of incident wave propagation, (2) the cylinder’s sectional diameters are about the same size, and (3) the smaller flap density the better power capturing performance.
{"title":"Geometry Optimization of Cylindrical Flaps of Oscillating Wave Surge Converters Using Artificial Neural Network Models","authors":"Chen-Chou Lin, Y. Chow, Yu-Yu Huang","doi":"10.1115/es2019-3878","DOIUrl":"https://doi.org/10.1115/es2019-3878","url":null,"abstract":"\u0000 This paper presents an optimization algorithm based on the Artificial Neural Network (ANN) to determine the optimal shape, size, and density for the cylindrical flap of the Bottom-Hinged Oscillating Wave Surge Converter (BH-OWSC) that can extract maximal wave power under a given wave condition. Eight parameters are selected, and their upper and lower bounds are set at the initial stage, and then 64 cases with different combinatorial parametric settings are generated by the Design of Experiment process. The 64 cases are then fed into FLOW-3D to simulate the operations of the BH-OWSC under the given wave condition for calculating the capture factor, establishing a database for subsequent ANN data training purpose.\u0000 To search the maximal capture factor in the specific range of the flap models, we fed 107 random models with various levels of design parameters into the ANN model, which adopts the backpropagation architecture and one hidden layer with ten neuron cells. After three complete random searches, and by simulating the ANN-derived flap’s geometry using FLOW-3D, the result shows that a maximal capture factor of 1.824 can be obtained. The major geometric features of the flap with maximal capture factor are (1) the cylinder axis of the flap inclines to the opposite direction of incident wave propagation, (2) the cylinder’s sectional diameters are about the same size, and (3) the smaller flap density the better power capturing performance.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115176582","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}
Nehemiah Emaikwu, D. Catalini, J. Muehlbauer, Y. Hwang, I. Takeuchi, R. Radermacher
Heat pumps based on the vapor compression cycle account for a significant portion of energy use around the world. However, growing demands for energy efficient and environmentally friendly technologies have created a need for new space conditioning approaches. Novel systems which use elastocaloric material have shown potential to replace traditional vapor compression due to high energy efficiency and use of environmentally friendly, solid-state refrigerants. The solid-state refrigerants exhibit the elastocaloric effect, a phenomenon that occurs when metal alloys experience stress-induced reversible phase transformations resulting in latent heat release or absorption. Prototypes built in the Center for Environmental Energy Engineering have utilized the active elastocaloric regeneration (AER) operating method to develop high temperature gradients between the ends of a regenerative heat exchanger made of tubular elastocaloric material. Though this schema significantly increases the temperature span developed by elastocaloric cooling devices, the current heat pump design leads to temperature degradation as a result of conduction along the length of the tubes in the regenerator. The novel regenerator concept presented in this work mitigates that issue by using short, thermally insulated tubes layers which also enables fluid flow over external surface areas of the material.
{"title":"Development of a Cascade Elastocaloric Regenerator","authors":"Nehemiah Emaikwu, D. Catalini, J. Muehlbauer, Y. Hwang, I. Takeuchi, R. Radermacher","doi":"10.1115/es2019-3887","DOIUrl":"https://doi.org/10.1115/es2019-3887","url":null,"abstract":"\u0000 Heat pumps based on the vapor compression cycle account for a significant portion of energy use around the world. However, growing demands for energy efficient and environmentally friendly technologies have created a need for new space conditioning approaches. Novel systems which use elastocaloric material have shown potential to replace traditional vapor compression due to high energy efficiency and use of environmentally friendly, solid-state refrigerants.\u0000 The solid-state refrigerants exhibit the elastocaloric effect, a phenomenon that occurs when metal alloys experience stress-induced reversible phase transformations resulting in latent heat release or absorption. Prototypes built in the Center for Environmental Energy Engineering have utilized the active elastocaloric regeneration (AER) operating method to develop high temperature gradients between the ends of a regenerative heat exchanger made of tubular elastocaloric material.\u0000 Though this schema significantly increases the temperature span developed by elastocaloric cooling devices, the current heat pump design leads to temperature degradation as a result of conduction along the length of the tubes in the regenerator. The novel regenerator concept presented in this work mitigates that issue by using short, thermally insulated tubes layers which also enables fluid flow over external surface areas of the material.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114620052","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}
Falling particle receivers are an emerging technology for use in concentrating solar power systems. In this work, quartz tubes cut in half to form tube shells (referred to as quartz half-shells) are investigated for use as a full or partial aperture cover to reduce radiative and advective losses from the receiver. A receiver subdomain and surrounding air volume are modeled using ANSYS® Fluent®. The model is used to simulate fluid dynamics and heat transfer for the following cases: (1) open aperture, (2) aperture fully covered by quartz half-shells, and (3) aperture partially covered by quartz half-shells. We compare the percentage of total incident solar power lost due to conduction through the receiver walls, advective losses through the aperture, and radiation exiting out of the aperture. Contrary to expected outcomes, simulation results using the simplified receiver subdomain show that quartz aperture covers can increase radiative losses and, in the partially covered case, also increase advective losses. These increased heat losses are driven by elevated quartz half-shell temperatures and have the potential to be mitigated by active cooling and/or material selection.
{"title":"Effect of Quartz Aperture Covers on the Fluid Dynamics and Thermal Efficiency of Falling Particle Receivers","authors":"L. Yue, Brantley Mills, C. Ho","doi":"10.1115/es2019-3910","DOIUrl":"https://doi.org/10.1115/es2019-3910","url":null,"abstract":"\u0000 Falling particle receivers are an emerging technology for use in concentrating solar power systems. In this work, quartz tubes cut in half to form tube shells (referred to as quartz half-shells) are investigated for use as a full or partial aperture cover to reduce radiative and advective losses from the receiver. A receiver subdomain and surrounding air volume are modeled using ANSYS® Fluent®. The model is used to simulate fluid dynamics and heat transfer for the following cases: (1) open aperture, (2) aperture fully covered by quartz half-shells, and (3) aperture partially covered by quartz half-shells. We compare the percentage of total incident solar power lost due to conduction through the receiver walls, advective losses through the aperture, and radiation exiting out of the aperture. Contrary to expected outcomes, simulation results using the simplified receiver subdomain show that quartz aperture covers can increase radiative losses and, in the partially covered case, also increase advective losses. These increased heat losses are driven by elevated quartz half-shell temperatures and have the potential to be mitigated by active cooling and/or material selection.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116300411","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}
Renewable production of hydrogen offers a clean and sustainable replacement of fossil fuels. As an energy carrier hydrogen is compressed and stored at high pressures. Pressurized water electrolysis improves plant performance as hydrogen compression is an energy intensive process. This work analyzes hydrogen production over the temperature range of 100°C to 800°C and pressure range of 1 bar to 700 bar. The sensitivity of plant efficiency to hydrogen compression technology and waste heat recovery is investigated. This study reveals that a lower-heating-value electric energy efficiency of 84% can be achieved when pressurized electrolysis avoids the inefficiencies of hydrogen compression. With the availability of high-quality waste heat plant efficiency can reach 98% for a pipeline distribution scenario at 3MPa. When no waste heat is available plant efficiency is independent of electrolysis temperature. For hydrogen use in the transportation sector, pressurized supercritical water electrolysis at 800°C has the potential to improve plant efficiency by 14% from a baseline of non-pressurized electrolysis at 800°C.
{"title":"A System Analysis of Pressurized Electrolysis for Compressed Hydrogen Production","authors":"Ryan T. Hamilton, D. McLarty","doi":"10.1115/es2019-3908","DOIUrl":"https://doi.org/10.1115/es2019-3908","url":null,"abstract":"\u0000 Renewable production of hydrogen offers a clean and sustainable replacement of fossil fuels. As an energy carrier hydrogen is compressed and stored at high pressures. Pressurized water electrolysis improves plant performance as hydrogen compression is an energy intensive process. This work analyzes hydrogen production over the temperature range of 100°C to 800°C and pressure range of 1 bar to 700 bar. The sensitivity of plant efficiency to hydrogen compression technology and waste heat recovery is investigated. This study reveals that a lower-heating-value electric energy efficiency of 84% can be achieved when pressurized electrolysis avoids the inefficiencies of hydrogen compression. With the availability of high-quality waste heat plant efficiency can reach 98% for a pipeline distribution scenario at 3MPa. When no waste heat is available plant efficiency is independent of electrolysis temperature. For hydrogen use in the transportation sector, pressurized supercritical water electrolysis at 800°C has the potential to improve plant efficiency by 14% from a baseline of non-pressurized electrolysis at 800°C.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131150578","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}
Efficient hydrogen flow control is of great importance to ensure the reliable operation of an automotive fuel cell system because it is closely associated with the safety and the economic efficiency. In this study, an effective hydrogen flow control algorithm for hydrogen excess ratio control is addressed by pointing out the recovery speed and overshoot response. Unlike previous studies on the hydrogen management systems of an automotive fuel cell, this study presents an analytic hydrogen tank model which can present the characteristics of the discharge and charge of hydrogen from a type 4 hydrogen tank. To this end, a mode reference adaptive control (MRAC) based on proportional-integral (PI) control is introduced, to ensure robust hydrogen flow during the dynamic operation of fuel cell system. The MRAC was compared with the nominal PI control and PWM control in the hydrogen management system of an automotive fuel cell operating within normal conditions, under steady-state responses and transient. Based on these result, it can further demonstrate that the MRAC algorithm shows better recovery speed and tracking performance than the nominal PI, and PWM control algorithm with respect to the transient behaviors.
{"title":"Robust Control of Hydrogen Flow for an Automotive Fuel Cell System via Model Reference Adaptive Control","authors":"J. Hwang, Sangseok Yu","doi":"10.1115/es2019-3882","DOIUrl":"https://doi.org/10.1115/es2019-3882","url":null,"abstract":"\u0000 Efficient hydrogen flow control is of great importance to ensure the reliable operation of an automotive fuel cell system because it is closely associated with the safety and the economic efficiency. In this study, an effective hydrogen flow control algorithm for hydrogen excess ratio control is addressed by pointing out the recovery speed and overshoot response. Unlike previous studies on the hydrogen management systems of an automotive fuel cell, this study presents an analytic hydrogen tank model which can present the characteristics of the discharge and charge of hydrogen from a type 4 hydrogen tank. To this end, a mode reference adaptive control (MRAC) based on proportional-integral (PI) control is introduced, to ensure robust hydrogen flow during the dynamic operation of fuel cell system. The MRAC was compared with the nominal PI control and PWM control in the hydrogen management system of an automotive fuel cell operating within normal conditions, under steady-state responses and transient. Based on these result, it can further demonstrate that the MRAC algorithm shows better recovery speed and tracking performance than the nominal PI, and PWM control algorithm with respect to the transient behaviors.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131175049","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}
Estimation of Energy Savings from Community Scale Solar Water Heating in Los Angeles County explores the extent to which community scale solar water heating systems, designed for residential structures in Los Angeles County and constructed from currently available technology, can displace natural gas for domestic water heating through a series of case studies. The effects of policy, urban form, and building characteristics on the performance of solar water heating systems, as well as community scale solar water heating’s potential to reduce emissions from the residential housing sector, are discussed herein. Three public and three private residential developments were selected as case studies for community scale solar water heating, with numbers of units and residents ranging from the tens to hundreds. These six cases were draw from the pool of approximately 19,000 “energy communities” in Los Angeles County, i.e. residential developments where the installation and operation of community scale solar water heating systems is broadly feasible. The six properties were also chosen to represent a cross-section housing stock and development patterns common in Los Angeles County, and different levels of suitability for solar water heating. The performance of and energy savings from solar water heating systems on each of these properties is then evaluated using the National Renewable Energy Laboratory’s System Advisor Model (NREL SAM). The results of the system simulations reveal how building characteristics and hot water demand affect the performance of community scale solar water heating systems. The case study sites’ system simulations show that residential developments with community scale solar water heating systems reach an average solar fraction of 50%. The results of the case studies indicate that community scale solar water heating is viable as an emissions reduction technology for the residential building sector in Mediterranean climates. However, side-by-side comparison with solar PV systems and other water heating technologies (such as grid-connected heat pumps) is necessary to determine optimality in terms of cost, emissions reduction, and thermal efficiency) in specific contexts.
{"title":"Evaluating the Energy Savings From Community Scale Solar Water Heating in Los Angeles County: Residential Case Studies","authors":"R. Cudd, K. Anderson, Wael Yassine","doi":"10.1115/es2019-3960","DOIUrl":"https://doi.org/10.1115/es2019-3960","url":null,"abstract":"\u0000 Estimation of Energy Savings from Community Scale Solar Water Heating in Los Angeles County explores the extent to which community scale solar water heating systems, designed for residential structures in Los Angeles County and constructed from currently available technology, can displace natural gas for domestic water heating through a series of case studies. The effects of policy, urban form, and building characteristics on the performance of solar water heating systems, as well as community scale solar water heating’s potential to reduce emissions from the residential housing sector, are discussed herein. Three public and three private residential developments were selected as case studies for community scale solar water heating, with numbers of units and residents ranging from the tens to hundreds. These six cases were draw from the pool of approximately 19,000 “energy communities” in Los Angeles County, i.e. residential developments where the installation and operation of community scale solar water heating systems is broadly feasible. The six properties were also chosen to represent a cross-section housing stock and development patterns common in Los Angeles County, and different levels of suitability for solar water heating. The performance of and energy savings from solar water heating systems on each of these properties is then evaluated using the National Renewable Energy Laboratory’s System Advisor Model (NREL SAM). The results of the system simulations reveal how building characteristics and hot water demand affect the performance of community scale solar water heating systems. The case study sites’ system simulations show that residential developments with community scale solar water heating systems reach an average solar fraction of 50%. The results of the case studies indicate that community scale solar water heating is viable as an emissions reduction technology for the residential building sector in Mediterranean climates. However, side-by-side comparison with solar PV systems and other water heating technologies (such as grid-connected heat pumps) is necessary to determine optimality in terms of cost, emissions reduction, and thermal efficiency) in specific contexts.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123989687","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}
In Singapore, roughly 20% of the energy consumed by households is used for water heating and almost all the energy consumed by conventional electric water heaters. One of the significant potential energy saving opportunities lies in using energy-efficient water heating appliances. Recently, there has been a move towards energy-saving design and the use of natural refrigerants over fluorocarbons. Unlike conventional electric storage water heaters, which use electricity to heat water directly, heat pump storage water heaters use electricity only to operate a pump that circulates refrigerants around the system. This refrigerant collects heat from the surrounding atmosphere and transfers it to the water. CO2 heat pumps have low global warming potential when compared to other refrigerants based heat pumps, has zero ozone depletion potential, inexpensive, non-flammable, generate high temperature. In this project, a comparative analysis of three different water heater types has been presented based on real-time usage and living-lab conditions under the tropical climate of Singapore. These three types are: 1. Electrical heater storage type 2. Hybrid heat pump with auxiliary electrical heating water heater 3. CO2 heat pump water heater without auxiliary heating Study found significant energy saving using CO2 heat pump compared to other water heating system and also better for environment.
{"title":"Study of Different Types of Water Heating Systems - Under Living Lab Conditions","authors":"S. Dubey","doi":"10.1115/es2019-3944","DOIUrl":"https://doi.org/10.1115/es2019-3944","url":null,"abstract":"\u0000 In Singapore, roughly 20% of the energy consumed by households is used for water heating and almost all the energy consumed by conventional electric water heaters. One of the significant potential energy saving opportunities lies in using energy-efficient water heating appliances. Recently, there has been a move towards energy-saving design and the use of natural refrigerants over fluorocarbons. Unlike conventional electric storage water heaters, which use electricity to heat water directly, heat pump storage water heaters use electricity only to operate a pump that circulates refrigerants around the system. This refrigerant collects heat from the surrounding atmosphere and transfers it to the water. CO2 heat pumps have low global warming potential when compared to other refrigerants based heat pumps, has zero ozone depletion potential, inexpensive, non-flammable, generate high temperature. In this project, a comparative analysis of three different water heater types has been presented based on real-time usage and living-lab conditions under the tropical climate of Singapore. These three types are:\u0000 1. Electrical heater storage type\u0000 2. Hybrid heat pump with auxiliary electrical heating water heater\u0000 3. CO2 heat pump water heater without auxiliary heating\u0000 Study found significant energy saving using CO2 heat pump compared to other water heating system and also better for environment.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127894100","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}
Yang Chen, Fadwa Dababneh, Bei Zhang, Saiid Kassaee, Brennan T. Smith, Xiaobing Liu, A. Momen
Due to the promising potential for environmental sustain-ability, there has been a significant increase of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEV) in the market. To support this increasing demand for EVs and PHEVs, challenges related to capacity planning and investment costs of public charging infrastructure must be addressed. Hence, in this paper, a capacity planning problem for EV charging stations is developed and aims to balance current capital investment costs and future operational revenue. The charging station considered in this work is assumed to be equipped with solar photovoltaic panel (PV) and an energy storage system which could be electric battery or the recently invented hydro-pneumatic energy storage (GLIDES, Ground-Level Integrated Diverse Energy Storage) system. A co-optimization model that minimizes investment and operation cost is established to determine the global optimal solution while combining the capacity and operational decision making. The operational decision making considers EV mobility which is modeled as an Erlang-loss system. Meanwhile, stochastic programming is adopted to capture uncertainties from solar radiation and charging demand of the EV fleet. To provide a more general and computationally efficient model, main configuration parameters are sampled in the design space and then fixed in solving the co-optimization model. The model can be used to provide insights for charging station placement in different practical situations. The sampled parameters include: the total number of EV charging slots, the PV area, the maximum capacity of the energy storage system, and daily mean EV arrival number in the Erlang-loss system. Based on the sampled parameter combinations and its responses, black-box mappings are then constructed using surrogate models (RBF, Kriging etc). The effectiveness of proposed surrogate modeling approach is demonstrated in the numerical experiments.
由于具有良好的环境可持续性潜力，电动汽车(ev)和插电式混合动力汽车(PHEV)在市场上有了显著的增长。为了支持对电动汽车和插电式混合动力汽车日益增长的需求，必须解决与容量规划和公共充电基础设施投资成本相关的挑战。因此，本文研究了电动汽车充电站的容量规划问题，旨在平衡当前的资本投资成本和未来的运营收益。本文所考虑的充电站假定安装有太阳能光伏板(PV)和储能系统，储能系统可以是蓄电池，也可以是最近发明的油气储能(GLIDES, Ground-Level Integrated diversity energy storage)系统。建立了投资和运行成本最小的协同优化模型，将运力和运营决策相结合，确定了全局最优解。将电动汽车移动性建模为Erlang-loss系统，进行运营决策。同时，采用随机规划方法捕捉太阳辐射和电动汽车充电需求的不确定性。为了提供一个更通用和计算效率更高的模型，在设计空间中对主要配置参数进行采样，然后在求解协同优化模型时进行固定。该模型可为不同实际情况下的充电站布局提供参考。采样参数包括:电动汽车充电槽总数、光伏面积、储能系统最大容量、日均电动汽车到达Erlang-loss系统数量。基于采样参数组合及其响应，然后使用代理模型(RBF, Kriging等)构建黑盒映射。数值实验验证了该方法的有效性。
{"title":"Surrogate Modeling for Capacity Planning of Charging Station Equipped With PV and Hydropneumatic Energy Storage","authors":"Yang Chen, Fadwa Dababneh, Bei Zhang, Saiid Kassaee, Brennan T. Smith, Xiaobing Liu, A. Momen","doi":"10.1115/es2019-3831","DOIUrl":"https://doi.org/10.1115/es2019-3831","url":null,"abstract":"\u0000 Due to the promising potential for environmental sustain-ability, there has been a significant increase of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEV) in the market. To support this increasing demand for EVs and PHEVs, challenges related to capacity planning and investment costs of public charging infrastructure must be addressed. Hence, in this paper, a capacity planning problem for EV charging stations is developed and aims to balance current capital investment costs and future operational revenue. The charging station considered in this work is assumed to be equipped with solar photovoltaic panel (PV) and an energy storage system which could be electric battery or the recently invented hydro-pneumatic energy storage (GLIDES, Ground-Level Integrated Diverse Energy Storage) system. A co-optimization model that minimizes investment and operation cost is established to determine the global optimal solution while combining the capacity and operational decision making. The operational decision making considers EV mobility which is modeled as an Erlang-loss system. Meanwhile, stochastic programming is adopted to capture uncertainties from solar radiation and charging demand of the EV fleet. To provide a more general and computationally efficient model, main configuration parameters are sampled in the design space and then fixed in solving the co-optimization model. The model can be used to provide insights for charging station placement in different practical situations. The sampled parameters include: the total number of EV charging slots, the PV area, the maximum capacity of the energy storage system, and daily mean EV arrival number in the Erlang-loss system. Based on the sampled parameter combinations and its responses, black-box mappings are then constructed using surrogate models (RBF, Kriging etc). The effectiveness of proposed surrogate modeling approach is demonstrated in the numerical experiments.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125491446","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}
Through the flux characterization of a high flux solar simulator, all directional information of the flux distribution is lost. Therefore, an experimental approach is necessary to restore the directional information. In this study, 13 heat flux maps were experimentally obtained from a 10 kWe Xenon arc solar simulator through an indirect flux mapping technique, implementing the use of one Lambertian target. The formulation of the inverse problem of experimentally determining the intensity distribution at the focal plane is presented. In addition, a Monte Carlo ray tracing in-house code modeling the Xenon arc is developed and used to generate the experimentally obtained flux maps and intensity at the focal plane to be used as a reference. Two intensity interpolation schemes were examined; a zeroth and first-order schemes. It is shown that a first order interpolation unnecessary complicates the inverse problem. The percentage error reduced from 90.9% to 82.6% when changing the interpolation scheme from a first to zeroth-order, in addition to a five times reduction in computational time. Furthermore, a new approach of constraining the formulated system of equations with an equality constraint that works by eliminating some of the intensity values that cannot be traced back to the ellipsoidal reflector is proposed. Therefore, it can be used as a technique to change the ill-conditioned problem to a well-conditioned one, without depending heavily on Tikhonov regularization methods. This new approach provided intensity values at the focal plane with a reduced percentage error from 52.2% to 30.4% for the zeroth-order interpolation scheme.
{"title":"Intensity Distribution From a Single-Bulb Solar Simulator Identification Through Inverse Ray Tracing","authors":"M. Abuseada, Nesrin Ozalp","doi":"10.1115/es2019-3860","DOIUrl":"https://doi.org/10.1115/es2019-3860","url":null,"abstract":"\u0000 Through the flux characterization of a high flux solar simulator, all directional information of the flux distribution is lost. Therefore, an experimental approach is necessary to restore the directional information. In this study, 13 heat flux maps were experimentally obtained from a 10 kWe Xenon arc solar simulator through an indirect flux mapping technique, implementing the use of one Lambertian target. The formulation of the inverse problem of experimentally determining the intensity distribution at the focal plane is presented. In addition, a Monte Carlo ray tracing in-house code modeling the Xenon arc is developed and used to generate the experimentally obtained flux maps and intensity at the focal plane to be used as a reference. Two intensity interpolation schemes were examined; a zeroth and first-order schemes. It is shown that a first order interpolation unnecessary complicates the inverse problem. The percentage error reduced from 90.9% to 82.6% when changing the interpolation scheme from a first to zeroth-order, in addition to a five times reduction in computational time. Furthermore, a new approach of constraining the formulated system of equations with an equality constraint that works by eliminating some of the intensity values that cannot be traced back to the ellipsoidal reflector is proposed. Therefore, it can be used as a technique to change the ill-conditioned problem to a well-conditioned one, without depending heavily on Tikhonov regularization methods. This new approach provided intensity values at the focal plane with a reduced percentage error from 52.2% to 30.4% for the zeroth-order interpolation scheme.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123310706","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}
J. Lei, E. González, Yingchen Yang, Ying Zhang, Ben Xu
Ocean wave is a rich source of renewable energy with much higher power density than winds. Various WEC technologies have been proposed or are under development. In this study, we developed a 2-dimensional (2D) model and analyzed the rotational motion of the lift-type rotor’s blade under steady flow and unsteady flow. The numerical model was validated by experiments under steady flow. Fast Fourier Transform (FFT) analysis was performed to identify the major contribution of frequency in terms of vortexes generated in the flow field. A comparative study was also performed by comparing all the cases in terms of energy conversion efficiency under different wave conditions. It turns out that the efficiency of energy conversion has a maximum value in the steady flow, while the efficiency for unsteady flow keeps decreasing, therefore this is highly due to the increased dissipation because of the oscillating. When the flow is oscillating, the rotational speed of the rotor under periodic condition is lower than the rotational velocity with steady flow, and a curve fitting was performed in this study to predict the periodic average rotational speed. We conclude that for oscillating flow a minimum of 1.6% energy conversion efficiency can be expected, but it may vary for the actual ocean waves. It is expected the current 2D simulation results can contribute to the wave energy community, especially when the rotor design and optimization is required.
{"title":"Numerical Simulation of Wave Energy Converter With Hydrofoil Blades Under Various Wave Conditions","authors":"J. Lei, E. González, Yingchen Yang, Ying Zhang, Ben Xu","doi":"10.1115/es2019-3936","DOIUrl":"https://doi.org/10.1115/es2019-3936","url":null,"abstract":"\u0000 Ocean wave is a rich source of renewable energy with much higher power density than winds. Various WEC technologies have been proposed or are under development. In this study, we developed a 2-dimensional (2D) model and analyzed the rotational motion of the lift-type rotor’s blade under steady flow and unsteady flow. The numerical model was validated by experiments under steady flow. Fast Fourier Transform (FFT) analysis was performed to identify the major contribution of frequency in terms of vortexes generated in the flow field. A comparative study was also performed by comparing all the cases in terms of energy conversion efficiency under different wave conditions. It turns out that the efficiency of energy conversion has a maximum value in the steady flow, while the efficiency for unsteady flow keeps decreasing, therefore this is highly due to the increased dissipation because of the oscillating. When the flow is oscillating, the rotational speed of the rotor under periodic condition is lower than the rotational velocity with steady flow, and a curve fitting was performed in this study to predict the periodic average rotational speed. We conclude that for oscillating flow a minimum of 1.6% energy conversion efficiency can be expected, but it may vary for the actual ocean waves. It is expected the current 2D simulation results can contribute to the wave energy community, especially when the rotor design and optimization is required.","PeriodicalId":219138,"journal":{"name":"ASME 2019 13th International Conference on Energy Sustainability","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126596849","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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