bluuebunny/crossref_metadata_2025_split huggingface dataset:
Receiver Outlet Temperature Control for Falling Particle Receiver Applications
Authors: Schroeder Nathan , Laubscher Henk , Mills Brantley , Ho Clifford K. 
Published: July 2021

Abstract
Falling particle receivers (FPRs) are being studied in concentrating solar power applications to enable high temperatures for supercritical CO2 (sCO2) Brayton power cycles. The falling particles are introduced into the cavity receiver via a linear actuated slide gate and irradiated by concentrated sunlight. The thickness of the particle curtain associated with the slide-gate opening dimension dictates the mass flow rate of the particle curtain. A thicker, higher mass flow rate, particle curtain would typically be associated with a smaller temperature rise through the receiver, and a thinner, lower mass flow rate, particle curtain would result in a larger temperature rise. Using the receiver outlet temperature as the process variable and the linear actuated slide gate as the input parameter a proportional, integral, and derivative (PID) controller was implemented to control the temperature of the particles leaving the receiver. The PID parameters were tuned to respond in a quick and stable manner. The PID controlled slide gate was tested using the 1 MW receiver at the National Solar Thermal Test Facility (NSTTF). The receiver outlet temperature was ramped from ambient to 800°C then maintained at the setpoint temperature. After reaching a steady-state, perturbations of 15%–20% of the initial power were applied by removing heliostats to simulate passing clouds. The PID controller reacted to the change in the input power by adjusting the mass flow rate through the receiver to maintain a constant receiver outlet temperature. A goal of ±2σ ≤ 10°C in the outlet temperature for the 5 minutes following the perturbation was achieved.
Dynamic Simulation of Organic Rankine Cycle-Assisted Ground-Source Heat Pump Based Micro-Cogeneration System in Cold Climates: A Case Study in Canada
Authors: Yaïci Wahiba , Entchev Evgueniy , Longo Michela 
Published: July 2021

Abstract
As the energy needed for heating and cooling involves a substantial amount (&gt; 80%) of residential energy utilisation in Canada, there is a demand for ultra-efficient energy systems for heating, cooling, and power generation. Two efficient systems to assist these systems are ground-source heat pumps (GSHPs) and organic Rankine cycles (ORCs). Of particular interest, this paper presents the integration of these two systems in a parallel configuration. A transient simulation model developed in TRNSYS program has been utilised to simulate the thermal performance of the combined ORC-GSHP based microco/trigeneration system. This later supplies heating and cooling to the residential load during the heating mode as required, with the capability to switch to a charging mode, where the ORC unit is directly coupled to the ground heat exchanger (GHE), which operates as a thermal energy storage and provides energy to the GSHP. The feasibility of this combined system configuration as well as its comparison with a conventional GSHP system are investigated for use in residential application in Ottawa, Canada temperature conditions.
Results disclosed that the proposed micro-cogeneration system had the operating hours and performance of the GSHP improved by the addition of the ORC unit, resulting in about 11.8% reduction in hours in the colder city of Ottawa. The COP (coefficient of performance) of the GSHP system sustained a much higher value overall due to the addition of the ORC system to maintain the GHE storage temperature. In terms of net energy reduction between the conventional GSHP system and the ORC-assisted one, results revealed that Ottawa had energy usage reduction of 82.0%, demonstrating that the addition of an ORC to provide heating and recharge the GHE of a GSHP system has many advantages that could be accomplished by the end-user.
An Investigation of the Fuel Economy of a Drive Cycle Developed Using the Road Load Energy Criterion
Authors: Vasquez Peter , Quiros Edwin , Denoga Gerald Jo , Corpus Robert Michael , Lomotan Robert James 
Published: July 2021

Abstract
Efforts to mitigate climate change include lowering of greenhouse gas emissions by reducing fuel consumption in the transport sector. Various vehicle technologies and interventions for better fuel economy eventually require chassis dynamometer testing using drive cycles for validation. As such, the methodology to generate these drive cycles from on-road data should produce drive cycles that closely represent actual on-road driving from the fuel economy standpoint.
This study presents a comparison of the fuel economy measured from a drive cycle developed using road load energy as a major assessment criterion and the actual on-road fuel economy of a 2013 Isuzu Crosswind utility vehicle used in the UV Express transport fleet in Metro Manila, Philippines. In this approach to drive cycle construction from on-road data, the ratio of the total road load energy of the generated drive cycle to that of the on-road trip is made the same ratio as their respective durations. On-road velocity and fuel consumption were recorded as the test vehicle traversed the 42.5 km. Sucat to Lawton route and vice versa in Metro Manila. Gathered data were processed to generate drive cycles using the modified Markov Chain approach. Three drive cycles of decreasing duration, based on the practicality of testing on a chassis dynamometer, were generated using three arbitrary data compression ratios. These drive cycles were tested using the same vehicle on the chassis dynamometer and compared with the on-road data using road load energy, fuel economy, average speed, and maximum acceleration. For the 893-seconds drive cycle generated, the road load energy error was 3.93% and fuel economy difference of 1.14%. For the 774-seconds cycle generated, the road load energy error was 4.34% and fuel economy difference was 0.91%. For the 664-seconds drive cycle, the road load energy error was 3.68% and fuel economy difference was 0.91%. On-road fuel economy for the 42.5-km. route averaged over nine round trips was 8.785 km/L. Based on the results, the road load energy criterion approach of drive cycle construction methodology can generate drive cycles which can very closely estimate on-road fuel economy.
Preliminary Design Development, Laboratory Testing, and Optimization of a 6.6 MW-Thermal All-Refractory Particle Heating Receiver
Authors: Yeung Ryan , Sarfraz Muhammad , Repole Kenzo , Jeter Sheldon , Alswaiyd Abdulelah , Alaqel Shaker , El-Leathy Abdelrahman , Al-Ansary Hany 
Published: July 2021

Abstract
Heat receiver design is an essential portion of Concentrating Solar Power (CSP) plants, particularly within CSP systems that are particle based. Particle based CSP promises higher operating temperatures and more cost-effective thermal energy storage than existing systems. Two general types of Particle Heat Receivers (PHR) are under development, variations of the free-falling curtain concept being developed by Sandia National Labs and an obstructed flow concept being developed by King Saud University (KSU) and Georgia Institute of Technology (GIT)[1, 2]. The obstructed flow design utilizes specifically engineered obstacles placed in the flow path of the particles to remove momentum and kinetic energy and promote lateral and depth-wise mixing. This design is named the discrete structure or DS-PHR. This paper focuses on development and design work that has been done with the existing DS-PHR developed by GIT and KSU. Previous iterations of the DS-PHR have utilized obstruction materials that include simple metal meshes, and ceramic formed into an inverted V-shapes or chevrons. However, these previous designs have some shortfalls. The metallic mesh design has structural integrity issues under intense radiation, inherent in a DS-PHR. The ceramic chevrons have a disadvantageously thick leading edge, which may intercept too much radiation and overheat. Current development has continued with improvements to remedy the issues of the previous design work. Experience, modeling, and testing have shown that a cavity receiver is preferred to reduce heat and particle loss in the system. Recent work has been devoted to developing a Discrete Structure Refractory Particle Heat Receiver (DS-RPHR) suitable for cavity installation working with a north-located field. The simplest suitable configuration is 5 flat ceramic plates, or absorber panels, arranged in an arc, forming a 15° angle of inclination, to improve particle retention in the system. To increase particle residence time, quartz rods are placed onto the back plane of the DS-PHR, in a hexagonal configuration. These serve as the momentum scrubbing obstructions as mentioned above. The performance of this design will be discussed in the following paper. This design has been extensively modeled using NREL’s Soltrace to evaluate thermal and optical performance. Modeling has shown high thermal efficiency in the design, as well as promising heat flux profiles across the receiver. Currently at KSU, a 300 kW-thermal testing facility has been constructed and used for high temperature testing. The final proposed 6.6 MW-thermal design, called the pre-commercial demonstration, will be built at a site owned and operated by Saudi Electric Company, in Waad Al-Shamal, 20 kilometers east of Tuarif, Saudi Arabi.
Least Cost Microgrid Resource Planning for the Natural Energy Laboratory of Hawaii Authority Research Park
Authors: Headley Alexander , Schenkman Benjamin , Olson Keith , Sombardier Laurence 
Published: July 2021

Abstract
The Natural Energy Laboratory of Hawaii Authority’s (NELHA) campus on The Island of Hawai’i supplies resources for a number of renewable energy and aquaculture research projects. There is a growing interest at NELHA to convert the research campus to a 100% renewable, islanded microgrid to improve the resiliency of the campus for critical ocean water pumping loads and to limit the increase in the long-term cost of operations. Currently, the campus has solar array to cover some electricity needs but scaling up this system to fully meet the needs of the entire research campus will require significant changes and careful planning to minimize costs. This study will investigate least-cost solar and energy storage system sizes capable of meeting the needs of the campus.
The campus is split into two major load centers that are electrically isolated and have different amounts of available land for solar installations. The value of adding an electrical transmission line if NELHA converts to a self-contained microgrid is explored by estimating the cost of resources for each load center individually and combined. Energy storage using lithium-ion and hydrogen-based technologies is investigated. For the hydrogen-based storage system, a variable efficiency and fixed efficiency representation of the electrolysis and fuel cell systems are used. Results using these two models show the importance of considering the changing performance of hydrogen systems for sizing algorithms.
Thermal-Economic Optimization of Moving Packed Bed Particle-to-SCO2 Heat Exchanger Using Particle Swarm Optimization
Authors: Zheng Yanjie , Hatzell Kelsey B. 
Published: July 2021

Abstract
Low cost (&lt; $150 kWt−1) and high heat-transfer coefficient particle heat exchangers may enable high temperature operation of high efficiency power cycles (supercritical CO2/air Brayton) [1–3]. Currently, these heat exchangers are cost-prohibitive and require large surface areas due to ineffective particle-particle and particle-CO2 heat transfer. Particle heat transfer media are examples of complex material systems that can display a re-configurable mesostructure during flow or shearing processes. This deformation or rearrangement in the underlying active material can cause a decrease in the thermal transport properties and limit the heat-transfer coefficient. For future adoption, it is critical that we gain a greater understanding of how local (particle-particle) thermophysical properties are affected by system architecture/design. Traditional heat exchanger optimization approaches are limited and often lead to non-feasible design approaches. Here, we employ a stochastic and evolutionary method, particle swarm optimization (PSO), to perform a multi-objective optimization for the particle-to-sCO2 shell-and-plate heat exchanger for two state-of-the-art particulate materials (i.e., Accucast ID50K and CARBO HSP). The objective function for optimization considers the minimum payback period (economics), entropy generation (thermodynamics), and volume (engineering). The results suggest that Accucast ID50K is preferable for a packed bed heat exchanger from the perspective of minimizing payback period and volume, while at a larger entropy generation rate than CARBO HSP.
Investigation of Operation Scheduling Optimization of Multi-Energy System in an Industrial Park With Consideration of Heat Storage
Authors: Zhang Shuting , Lin Xiaojie , Zhong Wei , Liu Sibin 
Published: July 2021

Abstract
Under the background of carbon neutralization, developing the multi-energy system (MES), which effectively integrates kinds of energy resources, is one of the keys to solving the environmental contradiction. At present, considering heat storage, the research on the optimal scheduling of MES, especially industrial park MES, focuses on the heat storage tank. The potential of the heating supply network (HSN) for heat storage is underestimated and its operational constraints haven’t been fully studied. Therefore, with consideration of quantitative heat storage in HSN, a day-ahead operation scheduling optimization model for MES is proposed. The model proposes a tubular heat storage body (THSB) to describe the heat storage characteristics and charge/discharge constraints of HSN and studies its impact on economic benefits and stability of output power. Equivalent method is used to quantify the heat storage capacity of HSN. Based on the established model, we take a real industrial park to optimize the operation plan of heating conditions in winter. Results indicate that the optimized scenario shows better economic benefits and output stability, which saves 1,303 yuan of operation cost per day.
Simulation of a Wet-Surface Bare Rod Heat Exchanger
Authors: Shaik Abdul Raheem , Al-Alili Ali , Alhassan Saeed M. 
Published: July 2021

Abstract
In this paper, a CFD analysis is carried out in ANSYS Fluent to investigate the enhancement of heat transfer and vapor condensation rate in a novel air-to-solid micro bare rod heat exchanger. Literature indicates that the enhancement of heat transfer occurs at the cost of increasing pressure drop across the heat exchanger; due to proximity of the rods. The heat exchanger is first modeled in Engineering Equation Solver (EES) to perform under Abu Dhabi’s hot and humid climate conditions. The heat exchanger is modelled to operate at low Reynolds number to increase the air residue time and allow condensation to occur. In the model, copper rods of diameter 1 mm are evenly spaced out between 2 plates to form the heat exchanger. Fixing the space occupied by the heat exchanger, i.e. volume occupied, the diameter of the copper rods is varied from 0.5 to 5 mm. The effect of the copper rods’ diameter and the spacing between the rods on the rate of vapor condensation, heat transfer, and pressure drop are investigated. Correlations for a micro bare rod heat exchanger exposed to a humid air stream are not available in the literature. Thus, using CFD modeling, the j (dry and wet side) and f factor correlations are determined for this novel heat exchanger operating at low Reynolds numbers. Lastly, the performance of the novel heat exchanger is compared to a fin-tube heat exchanger occupying the same volumetric space operating at the same conditions.
The Impact of COVID-19 on Energy Consumption in the United States: An Overview
Authors: Kahn Lindsey , Najafi Hamidreza 
Published: July 2021

Abstract
Lockdown measures and mobility restrictions implemented to combat the spread of the novel COVID-19 virus have impacted energy consumption patterns, particularly in the United States. A review of available data and literature on the impact of the pandemic on energy consumption is performed to understand the current knowledge on this topic. The overall decline of energy use during lockdown restrictions can best be identified through the analysis of energy consumption by source and end-user breakdown. Using monthly energy consumption data, the total 9-months use between January and September for the years 2015–2020 are calculated for each end-use. The cumulative consumption within these 9 months of the petroleum, natural gas, biomass, and electricity energy by the various end-use sectors are compared to identify a shift in use throughout time with the calculation of the percent change from 2019 to 2020. The analysis shows that the transportation sector experienced the most dramatic decline, having a subsequent impact on the primary energy it uses. A steep decline in the use of petroleum and natural gas by the transportation sector has had an inevitable impact on the emission of carbon dioxide and other air pollutants during the pandemic. Additionally, the most current data for the consumption of electricity by each state and each end-user in the times before and during the pandemic highlights the impact of specific lockdown procedures on energy use. The average total consumption for each state was found for the years 2015–2019. This result is used calculation of yearly growth rate and average annual growth rate in 2020 for each state and end-user. The total average annual growth rate for 2020 was used to find a correlation coefficient between COVID-19 case and death rates as well as population density and lockdown duration. To further examine the relationship a correlation coefficient was calculated between the 2020 average annual growth rate for all sectors and average annual growth rate for each individual end-user.
Performance Study of Thermoelectric Power Generators at Different Geometrical Configurations
Authors: Elsabahy Mohamed M. , Rabie Ramy , Ahmed Mahmoud 
Published: July 2021

Abstract
The thermoelectric generator (TEG) output power is mainly dependent on physical characteristics, dimensions, leg configuration, number of p-n thermocouples, and other parameters. Therefore, identifying the optimal leg configuration that attains the best performance is essential. The present work considers several leg configurations by the volume reduction of the conventional prism leg, without changing the shape class via decreasing basic dimensions (i.e. leg height or cross-sectional area) and with morphing the original prism into X and trapezoidal shapes. A three-dimensional thermo-electric model is developed to investigate the performance of TEG legs at the uni-thermocouple level. Besides, to determine the reliability of the proposed configurations, a wide range of thermal boundary conditions are applied on the hot side to resemble the realistic working environment that TEG might experience at room temperature on the cold side with natural convective cooling. The model is numerically simulated after being validated with the available experimental and numerical data. The comparison indicates that decreasing leg height adversely affects the TEG performance, whereas a significant enhancement in the performance is achieved (in order) for X, trapezoidal and reduced area shapes. However, the performance enhancement, i.e. power and efficiency, associated with the simple reduced area configuration is relatively close to those achieved by X or trapezoidal ones, raising many questions in terms of simplicity and manufacturing cost. The performed research further deepens our understanding of TEG performance enhancement via optimizing legs’ attributes at uni-thermocouple as a single building block of the full-size TEG module.
Preliminary Techno-Economic Optimization Of 1.3 MWe Particle Heating Receiver Based CSP Power Tower Plant for the MENA Region
Authors: Khatti Shakir Shakoor , Jeter Sheldon , Al-Ansary Hany 
Published: July 2021

Abstract
Due to increasing energy demand around the globe and potential environmental impacts of fossil fuels, it has become a crucial task for researchers to find alternatives to generate electricity from low-carbon resources at lower costs. Three types of advanced CSP are under consideration: systems heating salt, gas, or particulate. Particle heating receiver (PHR) based central receiver power tower CSP is an emerging technology that promises higher operating temperatures and more cost-effective thermal energy storage (TES) than feasible with existing or alternative CSP systems. For reasons stated above and others, we propose that the particle heating receiver (PHR) based CSP in the classic central receiver power tower (CRPT) configuration will be the most suitable especially in the promising Middle East and North Africa (MENA) region. Specifically, Duba, Al Wajih, and Wa’ad Al-Shamaal regions in Saudi Arabia have high direct normal irradiation (DNI) and represent potential locations. PHR based CSP power tower plant consists of a central receiver power tower with TES and cavity receiver, heliost at field, a high-temperature solar gas turbine with built-in fuel backup to operate in hybrid mode (using both fuel and solar-thermal resources). This study focuses on the optimization of a solar heat supply system (SHSS), consisting of a tower, cavity receiver, and heliostat field. SolarPILOT – Solar Power tower Integrated Layout and Optimization Tool is a field layout optimization tool developed by National Renewable Energy Laboratory (NREL). SolarPILOT is used in this study to generate the field layout of a 1.3 MWe power plant with a solar multiple (SM) of 2, 3, and 4. Cost models for the tower, receiver, and heliostats are developed using the data from research programs, contractors, manufacturing companies, and general cost engineering data and tools. System Advisor Model (SAM) is further used to simulate the annual performance of CSP tower plant including power block (high-temperature gas turbine) and TES using optical efficiency data from SolarPILOT to optimize PHR-based CSP tower plant. The results of this research are fundamental to the techno-economic analysis (TEA) of this and similar smaller-scale systems and will support the TEA of larger grid-connected and smaller off-grid systems operating independently or in conjunction with PV systems.