bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modified Single Slope Solar Still With External Reflectors
Authors: Alrashidi Abdullah 
Published: September 2024

Abstract
In this work, a single slope still with a single basin that has dimensions of 100 cm 100 cm and is composed of 2 mm thick galvanized iron-sheet, is designed with external reflectors to develop and maximize the system’s efficiency. This modification allows to increase the system’s heat inside the solar still that contains the desalinated water through a glass cover. The conventional design is compared with the modified design during daytime. The temperatures of the inner glass, outer glass, water in the basin, and the outside temperature were recorded every half an hour. The basin and reflectors were maintained as the same size. During testing, four external reflectors were used from the still’s four sides, and their effects on productivity were examined. The temperature of the distilled water, the inner and outer glass covers, the water in the basin, the stills with and without reflectors, and the surrounding temperature, pressure, wind speed, and direction were all monitored every half hour. Results of the test for a typical summer day showed that the water temperature increases until it reaches its peak in the afternoon because more solar energy is absorbed than is lost to the atmosphere. Around 2 pm, the amount of solar energy lost starts to outweigh the amount of solar radiation absorbed, which results in a decrease in water temperature due to glass has a lower temperature than water, it can condense vapor. Early in the day, when the water absorbs less energy, there is less productivity since the temperature differential between the water in the glass and the air is smaller. The maximum peak solar radiation intensity increased by roughly 17%. Also, glass, water and absorber temperatures were enhanced. Hourly and cumulative water productivities were improved by 40% and 50% respectively.
Techno-Economic and Environmental Performance Comparison of Different Systems for Space Heating Systems in Cold Climates – Case of the Bow Valley Municipalities
Authors: Darbandi Amirhossein , Castaneda Arias Isabella , Holm-Radford Max , Govedarica Aleksandra , Shor Roman , Mwesigye Aggrey 
Published: September 2024

Abstract
This study aims to investigate the feasibility of utilizing shallow geothermal systems for space heating and cooling in the Bow Valley region of Canada. Three building types, including a duplex, an apartment and a hotel, were considered. To evaluate the energy demand of each building type, building energy models were developed using BEopt™ and validated using actual gas consumption. To meet the energy needs of each building, the performance of various heating systems, such as forced-air furnaces, air-source heat pumps (ASHP), groundwater heat pumps (GWHP), ground-source heat pumps (GSHP), and electric resistance heaters, was evaluated. The analysis was based on realistic input data, geological information, and location-specific conditions. The results showed that GSHPs are the most energy-efficient heating system, followed by GWHPs, cold climate ASHP, conventional ASHP, electric resistance heating, and gas furnaces. In terms of CO2 emissions, GSHPs show the lowest emissions. For the duplex building, a GSHP emitted 44 tCO2 compared to 289 tCO2 for the high-efficiency gas furnaces. The economic viability of each system varied depending on factors such as location and natural gas prices. Compared to high-efficiency gas furnaces, the results showed that the payback period for GSHPs and GWHPs ranged from 15 to 40 years, while it was 15 to 30 years for ASHPs and cold climate ASHPs, depending on available grants and incentives and local energy prices.
The Optimized Operation Strategy of Centralized Water-Cooling Air Conditioning System in Multi-Terminal Data Center Based on Supply and Demand Matching
Authors: Ge Yuyao , Tu Rang 
Published: September 2024

Abstract
With the continuous development of digital economy, the number and scale of data centers are increasing year by year, and the energy consumption of data centers is also increasing. At present, most of the data center heat system operation regulation depends on artificial experience, to meet the needs of the safe operation of the server is considered, not from the perspective of energy saving, heat system of indoor side heat environment control, and the cold source system side is not according to the end demand and the demand difference between the end of the water supply temperature control and water flow optimization distribution, not only makes the natural cold source is not effectively use, and reduce the active cold source. For the multi-terminal data center with the centralized water cooling source system with natural cooling source, this study analyzed the heat transfer and thermodynamic process of the system, established the corresponding numerical model, and optimized the operation strategy of the system of centralized water-cooled air conditioning system in the data center. In view of the energy consumption waste of air conditioning system caused by supply and demand mismatch and excessive cooling in most data center current operation, this study proposes an personalized optimization strategy for centralized water-cooled air-conditioning systems in multi-terminal data centers based on supply-demand matching. Using this optimization method, a typical case was simulated and optimized with the outdoor environment of Beijing. Compared with the non-optimized working condition, the annual average chilled water supply temperature was raised from 12°C to 14.27°C, and the upper operating temperature of the natural cooling source was raised from 10°C to 15.897°C. Moreover, the NCM operation hours of the data center cooling source system were extended by 32.57% and the energy consumption of the cooling source system reduced by 28.70%.
Cost-Effectiveness Analysis for Solar Energy Harvesting Field With PV Panels at Optimized Tilt Angles Under Year-Round Weather Cycles
Authors: Gwesha Ammar O. , Li Peiwen , Alfulayyih Yasir M. 
Published: September 2024

Abstract
This study introduces the Sunray-Energy Algorithm (SEA), an innovative tool designed to estimate the maximum solar energy received by photovoltaic (PV) solar panels. Evaluating optimal tilt angles under year-round cloud cover, SEA yields annual energy of 2206.36, 2371.58, 2371.89, and 2407.40 for one-time, twice/year, quarterly, and monthly PV tilt angle adjustments. The application of SEA extends to a comprehensive cost analysis for The University of Arizona Tech Park’s Solar Zone in Tucson, AZ, USA. Predicted annual energy harvests range from 39.966 to 43.607 GWh, demonstrating SEA’s capacity estimation.
The application of SEA extends to a comprehensive cost analysis of PV Solar Panel Installation, emphasizing a case study within the Solar Zone at The University of Arizona Tech Park. The study assesses the solar field’s theoretical solar energy harvest (AEP) for a 37.3-acre area, considering various tilt adjustment frequencies. SEA predicts annual energy harvests of 39.966 GWh, 42.958 GWh, 42.964 GWh, and 43.607 GWh for one-time, twice/year, quarterly, and monthly adjustments, respectively. The algorithm demonstrates proficiency in predicting potential plant capacity, estimating capacities of 15.68 MW, 16.85 MW, 16.85 MW, and 17.11 MW for the above-mentioned adjustments, respectively.
Establishing a 6MW plant capacity aligned with the predicted maximum theoretical solar energy harvest, the study delves into the impact of degradation rates on Annual Energy Production (AEP). Over a 25-year lifespan, the plant is anticipated to produce 90% of its initial electricity, emphasizing long-term sustainability considerations. The Levelized Cost of Energy (LCoE) for the 6MW PV solar field is calculated as $44.05/MWh, $37.35/MWh, and $33.08/MWh for lifespans of 20, 25, and 30 years, respectively, aligning with industry benchmarks.
The study highlights the significant influence of orientation and tilt angle on solar energy reception and LCoE. An in-depth exploration of Operations and Maintenance (O&M) costs highlights their significant influence on LCoE. With variations in O&M costs from $13 to $25 per kilowatt-DC per year, the study emphasizes the importance of strategic decision-making in optimizing revenue outcomes. The solar farm’s impact on residential energy needs is assessed, indicating its potential to power approximately 1577 homes in the first year and 1372 homes after 20 years. The 6MW solar plant’s economic viability is supported by a short payback period of 6.78 to 7.63 years. Combining SEA with economic assessments, this research provides a comprehensive understanding of solar energy technologies.
Understanding Li-Ion Battery Degradation Under Realistic Loads
Authors: Mohammadi Efat , Headley Alexander John 
Published: September 2024

Abstract
Electrochemical systems, including batteries, play a pivotal role in the transition towards a low-carbon economy. The global rise in renewable energy adoption has stimulated a high demand for energy storage technologies. As more energy is derived from fluctuating renewable sources, energy storage systems capable of retaining this energy become increasingly valuable. Batteries serve to balance the demand for electricity with the supply from green energy sources. However, various degradation mechanisms impact electrochemical systems’ performance and longevity by affecting their different components. Therefore, understanding and mitigating these degradation phenomena is vital to improve the durability, efficiency, and reliability of these systems. The stability of electrochemical systems over time, particularly when powered by naturally intermittent renewable sources like solar or wind with fluctuating input power profiles, remains a complex issue. The escalating demand for Lithium-Ion Batteries (LIBs) across various sectors, ranging from portable devices to electric vehicles and grid-scale energy storage systems, underscores the importance of investigating battery degradation over time under realistic loading scenarios. To investigate these degradation mechanisms, novel in-situ or ex-situ characterization techniques are needed to capture the aging phenomena in batteries. Typically test methods used in existing literature are not realistic. Therefore, in this study, a Power-Hardware-in-the-Loop (PHIL) system is introduced to perform aging studies on various Li-ion chemistries under realistic load profiles. We developed a test station that can emulate real loading profiles and monitor system health in response. The aim of this research is to provide a tool to characterize the effect of differences in operating conditions such that we can develop control methods to minimize degradation rates. Here we present preliminary requirement on Li-ion battery real time testing to achieve an understanding of battery degradation phenomena in real-world applications.
Numerical Analysis of Solidification in Molten Salt-Air Shell-and-Tube Heat Exchangers
Authors: K. Raj Arun , B. Desai Nishith , Haglind Fredrik 
Published: September 2024

Abstract
The cyclic operation of molten salt heat exchangers raises concern regarding the potential freezing of salts due to their high freezing point. Therefore, pinpointing the initiation of salt solidification and forecasting the phase change behavior in high-temperature heat exchange processes is necessary, as these factors influence the design and operation of the heat exchangers. This paper presents a three-dimensional, transient computational fluid dynamics analysis of a pilot-scale molten salt-air-cooled exchanger with air on the shell-side and molten salt on the tube-side. We aim to replicate the conditions the molten salt experiences during operation in a concentrating solar power plant or pumped thermal energy systems. Consequently, the study explores the influence of the initial molten salt temperature and the baffle configuration on the air outlet temperature, pressure drop and onset of salt solidification. A realizable k-ε turbulence model was adopted to capture the turbulent viscosity and dissipation rate, and a segregated solver algorithm was used to iteratively solve the coupling between the pressure and velocity fields. The numerical model was validated using previous results of a shell-and-tube heat exchanger employing pure water as the shell-side fluid. The main novel contribution of this work is to estimate the time it takes until the molten salt begins to solidify within the tube bundle when air acts as the working fluid on the shell-side of a single segmented baffled shell-and-tube-type heat exchanger. Additionally, it aims to ascertain the impact of inclusion of a flow diverter on delaying the salt solidification. The findings indicate that varying the baffle configurations has little to no effect on the air outlet temperature nor on the onset of molten salt solidification for all tested configurations without a flow diverter. Concurrently, inclusion of flow diverter helps redistribute the flow near the shell inlet nozzle, thereby delaying the onset of solidification. Furthermore, the results suggest that about one-third of the total heat exchanger length proves to be ineffective in contributing to the heat transfer, due to the creation of recirculation zones. These results serve as a benchmark for future heat transfer analyses of the dynamic operation of the molten salt-air-cooled heat exchangers.
Assessment of Fluidized Bed Heat Exchanger Techno Economics Considering Parasitic Pumping Power
Authors: Lerch Dylan J. , Schroeder Nathan R. 
Published: September 2024

Abstract
The Department of Energy’s Solar Energy Technologies Office has down selected a particle-based heat transfer and storage medium as the technology most likely to decrease the levelized cost of energy of concentrating solar power to below their 0.05 $/kWh target by 2030. A particularly challenging component within a particle-based system is the particle to supercritical CO2 heat exchanger due to the relatively low thermal conductivity and poor heat transfer characteristics of the particle media. Fluidized bed heat exchangers have widely been used in industry for alternative applications and feature high particle side heat transfer coefficients that can help reduce the cost of the heat exchanger. This increase in heat transfer coefficient is achieved by bubbling air through the particles which increases their movement relative to the tube bundle heat transfer surface. The parasitic power associated with the delivery of air into the heat exchanger introduces a concern that the levelized cost of energy would be negatively impacted when compared to the state of the art parallel plate heat exchanger which relies on gravity for particle flow. The presented study reveals that the levelized cost of electricity of the fluidized bed heat exchanger design was up to 0.007 $/kWh lower than the state of the art parallel plate heat exchanger despite the increased parasitic power consumption. It is also presented that the increase in heat transfer coefficient, and thus decreased heat exchanger material, gained from increased airflow in the bed does not result in lower levelized cost of energy. The minimum air flow required for fluidization provides in the lowest levelized cost of energy due to the minimal parasitic power consumption.
A Low Cost 20 MW Commercial Ocean Thermal Energy Plant for Tropical Regions
Authors: Anderson James H. 
Published: September 2024

Abstract
Ocean Thermal Energy Conversion (OTEC) has been seriously proposed as a natural and clean source of electric power starting in the late 1880’s. Through the 20th and now in the 21st century there have been numerous experiments, cycle developments, testing of components, environmental studies, and even small plants that prove OTEC is possible. Constantly, however, the cumulative call argues for the actual construction and installation of a prototype OTEC plant of commercial size, connected to a national municipal electric grid. Most less developed and smaller developed island and coastal tropical nations generate the bulk of their power with diesel fuel. This paper will describe how a 20 MW net prototype commercial OTEC plant can be built and installed in hundreds of tropical locations around the world today and produce reliable, continuous, baseload electricity at a lower cost than that generated from diesel fuel. In addition, a prototype plant of the design presented here can be profitable for any investor even without subsidies.
Quantifying Thermal Discomfort in Built Environment for Major Cities in Saudi Arabia
Authors: Ullah Safi , Tahir Furqan , Al-Ghamdi Sami G. 
Published: September 2024

Abstract
Human-induced climate change has intensified the thermal discomfort people experience in urban living. Despite the substantial risks this poses to public health, there is a notable gap in comprehensive research assessing the spatial and temporal shifts in human thermal discomfort and its specific characteristics in hot-hyper arid regions, one such example is Saudi Arabia. During heat waves, daily temperatures may surpass 50°C in the country, presenting a substantial risk to the health and well-being of residents. It is estimated that the building energy requirement is more than 50% of the total power consumption. Hence, it is critical to quantify thermal discomfort in terms of both thermal stress and intensity. Therefore, this work focused on analyzing thermal discomfort using the universal thermal climate index (UTCI) for efficient building design. Five major cities including Dammam, Jeddah, Madinah, Makkah, and Riyadh, were selected and examined from 1980–2022. The prominent urban hubs have encountered notable rises in UTCI, registering an increase ranging from 0.30 to 0.54 °C, marked by heightened frequency and intensity during the study period. The study’s findings can inform building design, enhance human comfort conditions, and shape future building codes and policies.
Evaluation and CFD Based Improvements of Reactive Reversible Blade Turbine
Authors: Patil Abhay , Katcher Kelsi , Allison Tim , Cummings Scot 
Published: September 2024

Abstract
A Reactive Reversible Blade Turbine (RRBT) is a cross-flow type turbine design with multiple movable blades that pivot around their local axes to hydraulically balance the blade forces while passing through the negative drag portion of the flow regime. The RRBT allows the blades to react to the negative drag and freely rotate in a way that hydraulically balances the pressure loading. The blades “slice” through the water in a reverse motion, returning to a neutral position and resting against a stop, resulting in reduced resistance on the opposite side of the turbine shaft during rotation. This allows for a significant reduction of the negative drag during the single rotation of the turbine, which improves the power coefficients compared to the current state of the art and allows the turbine to operate at a slow-moving current. Although the design is simple, there is a broad design optimization space that can impact the performance and development of this turbine for various applications. This paper focuses on developing a transient numerical model using a moving mesh approach of a single blade to characterize the flow dynamics and performance estimation. The predicted power coefficient (Cp) of 0.219, using computational fluid dynamics (CFD), aligns well with the experimentally measured value of 0.2 at a 0.32 Tip Speed Ratio (TSR). Further investigation focuses on gaining a deeper understanding of turbine performance concerning changes in blade profile, blade angles, blade widths, and scaling effects. The design space exploration study reveals that the blade angle has a substantial impact on turbine performance, particularly in shifting the peak power coefficient with the TSR. As the blade angle increases, the power coefficient rises, peaking at around 72°, followed by a decrease as the blade angle further increases. The Reynolds number scaling also indicates an approximately 20% increase in peak Cp due to the increased hydrodynamic size for the scaling from 1X to 5X. It is essential to note that these findings are based on the analysis of a single blade, and additional investigation and experimental validation are necessary to comprehensively assess the performance of the proposed design modifications.
Water Transport in Membrane of PEM Fuel Cell Under Transient Operation
Authors: Nguyen Ngoc Dat , Trinh Ngoc Van , Kim Younghyeon , Yu Sangseok 
Published: September 2024

Abstract
In this study, the primary focus is investigating the transient behaviors of water transport in the membrane when the cell voltage reaches its lowest values during acceleration. To cope with the objective, this study involved the installation of multiple micro relative humidity and temperature sensors in the bipolar plate channels to measure the temperature and water distribution in the flow fields both on the cathode and anode of a single cell PEMFC. Experiments have been conducted to acquire temperature and water distribution change data under varying load conditions with different time intervals. The current density was systematically adjusted from 0.1A/cm2 to 0.4A/cm2. Time intervals of 0 seconds and 5 seconds have been introduced to control the rapidity of acceleration process. This approach allowed for examining water transport characteristics in the membrane during transient operation. Specifically, an ANN (Artificial Neural Network)-based model has been developed to predict membrane water content. The net water mole flux transported in the membrane as the sum of electro-osmotic force and back-diffusion force is calculated based on the measured temperature and relative humidity by combining the ANN-based model with other empirical correlations. The research provides visual information about the water transport in the membrane during the transient state. The data corresponding to different acceleration time intervals are compared to assess the time-dependent effects of load changes. It is evident that the time intervals of acceleration significantly influence the water characteristics in the membrane and output voltage of operating PEMFC. This study contributes significantly to enhancing the knowledge of water transport transient behaviors in the membrane of PEMFC, providing the foundation for further research to improve the performance and durability of PEMFC for transportation applications.