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As-cast binary Al–Si alloys containing ∼8, 12, 20, and 30 wt.% Si, representing the hypoeutectic, eutectic (12 wt.% Si), and hypereutectic compositions, were subjected to severe plastic deformation by friction stir processing (FSP) for grain refinement to 2.3–2.7 μm by dynamic recrystallization. Tensile tests conducted by differential strain rate test technique over the strain rates of 10−4 – 10−2 s−1 and test temperatures in the range of ∼840–530 K led to strain rate sensitivity index (m) varying from ∼0.04 to 0.40 depending on temperature, strain rate, and alloy composition. The constant initial strain rate tests conducted at 10−4 s−1 and 840 K exhibited a maximum elongation of 250% in the hypereutectic Al–20Si alloy, but the same increased linearly with m irrespective of alloy composition. Generally, with increasing Si content, the activation energy for deformation increased from 104.7 ± 14.4 kJ/mol for eutectic Al–12Si to 310.4 ± 32.3 kJ/mol for hypereutectic Al–30Si, which increased further to 572 ± 148 kJ/mol over the higher temperature range of 840–800 K. Analysis of observed deformation and microstructure behaviour supports the occurrence of superplasticity, whereby the accommodation of grain boundary sliding by grain boundary migration led to enhanced grain growth or else the local high-stress concentration at the particle-matrix interface led to cavity formation. There was no evidence of dynamic recrystallization during high-temperature tensile deformation but the flow softening observed is ascribed to the occurrence of concurrent cavitation. [ABSTRACT FROM AUTHOR]

In large buildings, effective load shedding and shifting and providing the maximum power through solar renewable sources remain challenges because of users' unpredictable load consumption. Conventionally, load shifting, load shedding, and load covering are majorly dependent on user inputs. The lack of user interest in participating in demand responses for effective load shifting and covering remains a problem. Effective load covering through renewables and user-friendly load shedding and shifting with maximized user participation are challenging and demand high-resolution user load consumption information, which are not possible without sophisticated communication and digital twins. In this research work, a novel fuzzy-logic-based cascaded decentralized load-controlling mechanism has been developed that manages the residential building load through load-shifting, load-covering, and load-shedding schemes without any communication protocols and digitization between residential units. The decentralized controller aims to effectively utilize the centralized resources of power generation with the effective automated participation of users. The quantification of the load shifting, covering, and shedding performed during peak hours was well covered under the load-covering scheme, and the results showed that flexibility capacities of 1617 kW were achieved for load covering, 294 kW for load shedding, and 166.34 kW through shifting. A total load of 60 kW, which was reduced during shedding and shifting, was well covered during load covering through renewables. [ABSTRACT FROM AUTHOR]

Power generation from fossil fuels is the biggest challenge in the next half of the century. Alternative power generation techniques such as solar photovoltaic (PV) show potential to act as a future fuel with a challenge to efficiently convert the harvested solar energy into electrical power. This investigation conclusively focused on setting a 2.160-kW solar PV system capable of working at a higher efficiency by developing a mechanical structure that optimizes power production and minimizes energy losses. In addition to that, solar PV system efficiencies at various tracking positions, performance coefficients during rainy and sunny days, and system degradation rates have also been investigated. The PVsyst v6.8 simulation tool was used to obtain the simulated results, which were compared with the actual experimental results. The parameters considered for the investigations include ambient temperature, irradiance, solar PV module surface temperature, solar PV voltage and current, wind velocity, and atmospheric turbidity. The solar PV system was evaluated based on two modes, namely, M1 (no tracking/fixed type) and M2 (manual tracking by changing the position of the solar PV system every hour). The predictive results obtained using PVsyst v6.8 concluded that total energy production from the installed system was 3,242 kWh/yr and 3,984 kWh/yr for M1 and M2, respectively. The performance ratio (PR), obtained from simulation, was 72% and 78% for M1 and M2, respectively, which was consistent with the experimental results, i.e., 70% and 72% for M1 and M2, respectively. Similarly, the power conversion efficiencies under standard temperature and conditions for both modes, simulated and experimental, were found to be 16.50% and 12.75%, respectively. The estimated degradation rate was observed in the range of -0.6% to -5.0%. [ABSTRACT FROM AUTHOR]

Due to global environmental impacts, the electric vehicle (EV) adoption rate is increasing. However, unlike conventional petrol vehicles, EVs take a considerable time to charge. EVs on the road with different battery charging statuses and driving demographics may cause uncertain peak time arrivals at charging stations. Battery-swappable charging stations are a quick and easier way to replace uncharged batteries with charged ones. However, charging due to uncertain EV arrival causes higher charging profiles posing load to the grid, management of charged and discharged batteries, and peak time charging tariffs. These challenges hinder the wide operation of battery-swappable charging stations. Nevertheless, a pre-assessment of peak hours using EV demographics can reduce congestion. In recent literature surveys for battery-swappable charging stations, spot congestion has not been given much attention, which has a direct influence on the sizing and operation of battery-swappable charging stations. This research study is focused on estimating peak time events using a novel integrated techno-economic assessment framework. A fuzzy-based parametric assessment tool is developed that identifies the factors that influence higher congestion events. Based on the peak event assessment, grid, and solar PV-based generation is optimized using mixed integer linear programming. In the final step, an environment analysis of a swappable charging station is performed. Furthermore, the results achieved using the proposed framework for battery-swappable charging stations (BSCSs) were compared with fast-charging (FC) stations. FC can economically perform well if integrated with solar PV systems; however, the capital cost is 80% greater than the BSCSs designed under the proposed framework. The operational cost of BSCSs is 39% higher than FC stations as they use 29% higher grid units than FC stations due to night operations under congestion. [ABSTRACT FROM AUTHOR]

Power augmentation in a small-scale horizontal axis wind turbine, with its rotor encased in a flanged diffuser is explored. The power output of the wind turbine varies with changes in the diffuser design and the resulting back pressure. Reduction in this back pressure also results in early flow separation at the diffuser surface, which hinders turbine performance. The main aim of this study is to numerically investigate the local configuration of the wind turbine location inside the diffuser by varying diffuser angles and wind speeds. Therefore, shroud and flange were modeled and analyzed using the computational fluid dynamic (CFD) analyses and experiments were performed at two wind speeds 6 m/s and 8 m/s with and without the diffuser for model validation. The divergence angle of 4° was found to have no flow separation, thus maximizing flow rate. The proposed design shows wind speed improvement of up to 1.68 times compared to the baseline configuration. The corresponding optimum flange height was found to be 250 mm. However, increasing the divergence angle had a similar output. The dimensionless location of wind turbine was found to be between 0.45 and 0.5 for 2° and 4° divergence angle respectively. Furthermore, the maximum augmentation location varies with wind speed and diffuser's divergence angle as described by dimensionless location of wind turbine, thus presenting a noteworthy contribution to the horizontal axis wind turbine area with the flanged diffuser. [ABSTRACT FROM AUTHOR]

In this research study, the design and performance evaluation of grid-tied photovoltaic systems has been carried out through experimentation, HelioScope simulation, and black-box machine learning methods for data-driven artificial intelligence system performance assessment and validation. The proposed systems are based on 15 kWp of monoperk and polyperk, which are separately installed in the industrial sector of Faisalabad, Pakistan. The experimental evaluation of the installed PV modules was performed from November 2020 to August 2021. The performance of the PV modules was evaluated by determining the annual average daily final yield (If), performance ratio (PR), and capacity factor (CF). The study showed that the annual average of daily final yield, performance ratio, and capacity factor for 15 kW polyperk was estimated to be 61.94 kWh, 84.17%, and 19.12, respectively. The annual average of daily final yield, performance ratio, and capacity factor for 15 kW monoperk was estimated to be 58.32 kWh, 81.42%, and 18.13, respectively. A comparison of final yield is obtained from simulation and real-time systems obtained from polyperk PV and monoperk. A significant mean error exists between the experimentation and simulation results which lie within the range of 1250 to 1470 kWh and 1600 to 1950 kWh, respectively. Substantial differences between both aforementioned results were initially tested and highlighted by statistical values; i.e., the standard error lies in-between 5 and 45% in polyperk crystalline and 5 and 25% in monocrystalline PV grid-connected module. Machine learning logistical regression evaluated that monoperk crystalline grid-connected system, experimental work was found to be more reliable with error difference reduces in off-peak months as compared to corresponding simulation study and vice versa for polyperk crystalline grid-connected system. Model accuracy after training and testing produced resulted up to 99.5% accuracy for either grid-connected experimentation or simulation outcomes with validation. [ABSTRACT FROM AUTHOR]

Electric discharge machining with a powder mix dielectric is a promising technique to harden a work piece's surface using electricity with a high energy density. The quality of the electrical discharge-machined surface is related to its surface integrity in which the surface's roughness, residual stresses, micro hardness and surface micro cracks are some of the major factors. In this research, graphite powder was mixed in a dielectric with a particle size of 20 µm, 30 µm, and 40 µm, with the concentration of the graphite powder ranging from 2 g/L to 4 g/L. Moreover, the peak current and pulse time on were also coupled with an additive of graphite powder to investigate the effect on the surface quality, i.e., the recast layer thickness, micro hardness and crater depth as well as the material removal rate (MRR) and tool wear rate (TWR). A Box–Behnken design was employed to design the experiments and the experimental results revealed that the graphite powder size and concentration coupled with the electrical parameters (peak current and pulse time on) significantly influenced the recast layer thickness, micro hardness, crater size, MRR and TWR. The crater depth and micro hardness were maximized at a higher concentration and particle size, while the recast layer thickness was reduced with a higher gain size. [ABSTRACT FROM AUTHOR]

A novel solution for optimized energy management comprising a microgrid system for industries in Pakistan is proposed. The proposed study considered microgrids based on photovoltaics, wind turbines, power storage systems, and dual-fuel (DF) generators as backup. A heuristic methodology with a cuckoo search algorithm (CSA) is presented for efficient power trading by scheduling machines. The study was conducted to prove that CSA is adaptable and flexible for self-governing choices for the efficient management and scheduling of machines and power trade between the microgrid and commercial grid. A mixed integer linear programming algorithm is introduced to optimize the system design problems that control decision making for the ideal operation management. A real-time pricing scheme is utilized for electricity price figures. The simulation results show the efficient performance of the proposed scheme to maximize profitability, reduction in electricity cost, and peak to average ratio. Furthermore, the proposed optimization technique was compared with a highly in-use strawberry algorithm to prove the supremacy of the proposed technique. The proposed efficient and robust energy management system was implemented in Shafi Dyeing Industry, Faisalabad, to validate the simulated model. [ABSTRACT FROM AUTHOR]

This paper presents the optimal design of a photovoltaic (PV) drip irrigation system. Designing a PV system is based on calculated motor power, solar irradiance level and other meteorological parameters at a certain geographical location. Therefore, a simulation study of the designed PV system were performed by a PVGIS simulation tool. The PVGIS simulation tool analyzes the potential of power generation with optimal PV modules tilt angle and orientation on a monthly and annual basis, and an analysis of the overall shading situation (horizon) as well as the internal shading between the PV module rows. The selection of water pump and motor depends upon the depth of water table and desired discharge and head to operate the irrigation system. Furthermore, a locally developed Solar-Drip Simulation Tool (SoSiT) was used for load and supply optimization. Based on ambient temperature, solar irradiation and water requirements, SoSiT calculates net generation by a PV system and resultant water output of the irrigation system. The particular drip irrigation site has two zones; the maximum water requirement for zone 1 (row crop) is 50,918.40 Liters/day and for zone 2 (orchards) is 56,908.80 L/day. From PVGIS simulation results, the maximum daily energy production of the designed PV system was 6.48 kWh and monthly energy production was 201 kWh in the month of May. SoSiT results showed that the PV system fulfilled the required crop requirement by only using 28% of the potential water supply, and 72% of the potential water supply from a solar-powered pump was not used. This value is high, and it is recommended to grow more or different crops to utilize the fuel-free electricity from the PV system. The unit cost of PV-powered drip irrigation is USD 0.1013/kWh, which is 4.74% and 66.26% lower than the cost of subsidized electricity and diesel, respectively. [ABSTRACT FROM AUTHOR]

Integration of a dual-fluid heat exchanger with a photovoltaic/thermal (PV/T) system has become increasingly important because it not only significantly reduces the photovoltaic (PV) solar cells' temperature but also produces additional thermal energy. In this study, energy, exergy, and economic analyses of a dual-fluid (water/air) PV/T system are performed in comparison with a reference PV module and single-fluid PV/T systems for the climate of Cheonan, South Korea. Daily and yearly performance evaluations of all of the aforementioned PV/T systems were carried out through experimentation. Based on the experimental findings, the economic feasibility of the dual-fluid PV/T system is assessed in the context of its financial benefits over both a shorter and longer period of time. Results show that the energy and exergy efficiencies of the dual-fluid PV/T system are significantly higher than those of single-fluid PV/T systems, by 20% and 11%, respectively. In addition, relevant to local domestic electricity price, the cost of energy is reduced by 80%, 60%, and 45% with the dual-fluid PV/T system and water and air type PV/T systems, respectively. Furthermore, using the dual-fluid PV/T system, extra revenue is generated through carbon credit by mitigating CO2 emissions into the atmosphere. [ABSTRACT FROM AUTHOR]

In this study, for the first time an advanced exergy analysis was applied to a solar hybrid food dehydrator to find out the causes of the inefficacies and to assess the actual improvement potential. The dryer was integrated with an evacuated solar tube collector and gas burner as a heating sources. Drying experiments were performed using bell pepper at 55 °C under three heating options i.e., gas, solar and dual. The rates of exergy destructions were split into unavoidable ( E d U N ) and avoidable ( E d A V ) which further split into four parameters termed unavoidable endogenous ( E d U N , E N ), unavoidable exogenous ( E d U N , E X ), avoidable endogenous ( E d A V , E X ) and avoidable exogenous (E d A V , E N ). Conventional exergy analysis revealed that drying chamber possess lower improvement potential rate (IP) than heating components while outcomes of advanced exergy analysis showed that both the design and system components interaction of heating unit imparted a major effect on its efficiency. Optimizing the operating conditions of the heating sources could reduce their higher amount of inefficiencies. The values of exergy efficiency for the overall system were calculated to be 86.66%, 84.18%, 83.74% (conventional) and 97.41%, 95.99%, 96.16% (advanced) under gas, dual and solar heating modes respectively. [ABSTRACT FROM AUTHOR]

This paper presents the results of a field study undertaken all over the Punjab, Pakistan, to evaluate the socio-economic and climatic impact of photovoltaic-operated high-efficiency irrigation systems (HEIS), i.e., drip and sprinkler irrigation systems. Nearly half of the rural population relies on agriculture for a living, and the recent energy crisis has had a negative impact on rural communities. Farmers' reliance on fossil fuels for the operation of irrigation systems has increased exponentially, resulting in the high costs of agricultural production. Primary data regarding on-farm agriculture and irrigation practices used in this study were collected through an intensive on-farm survey, while secondary data were taken from published reports and statistics. The results of the current investigation show that the installation of PV systems has resulted in the increased adoption of high-efficiency irrigation systems, a reduction in the high operational costs incurred on account of old diesel-powered pumping systems (with an annual saving of 6.6 million liters of diesel), a 100% increase in farmer's income, a reduction of 17,622 tons of CO2 emissions per annum, and 41% savings in water. The unit cost of PV-powered HEIS was found to be 0.1219 USD/kWh, which was 4% and 66% less than subsidized electricity cost and diesel cost, respectively. [ABSTRACT FROM AUTHOR]

Renewable-energy-resource-based microgrids can overcome excessive carbon footprints and increase the overall economic profile of a country. However, the intermittent nature of renewables and load variation may cause various control problems which highly affect the power quality (frequency and voltages) of the overall system. This study aims to develop an adaptive technique for the optimization of renewable energy resources (RERs). The proposed grid-tied microgrid has been designed using a wind-turbine (WT) based distributed generation, a photovoltaic (PV) system, a diesel generator as an emergency backup, and battery energy storage system (BESS). The flexible (residential) and non-flexible (industrial) loads are connected with the proposed grid. Matlab/Simulink has been used to evaluate the performance of the proposed optimization technique. Comparison with different in-use techniques shows that the proposed technique is more reliable and efficient than the state of the art optimization techniques currently in use. Moreover, this proposed system provides robust optimization of parameters of concern such as frequency and voltages, makes efficient use of the maximum power point tracking while regulating voltages, reduces the overall system cost, and increases economic profitability. [ABSTRACT FROM AUTHOR]

Fossil fuels are being depleted, resulting in increasing environmental pollution due to greenhouse gases and, consequently, emerging detrimental environmental problems. Therefore, renewable energy is becoming more important; hence, significant research is in progress to increase efficient uses of solar energy. In this paper, the thermal performance of a conical concentrating system with different heat transfer fluids at varied flow rates was studied. The conical-shaped concentrator reflects the incoming solar radiation onto the absorber surface, which is located at the focal axis, where the collected heat is transported through heating mediums or heat transfer fluids. Distilled water and nanofluids (Al2O3, CuO) were used in this study as the heat transfer fluids and were circulated through the absorber and the heat storage tank in a closed loop by a pump to absorb the solar radiation. The efficiency of the conical concentrating system was measured during solar noon hours under a clear sky. The collector efficiency was analyzed at different flow rates of 2, 4, and 6 L/min. The thermal efficiency, calculated using different heat transfer fluids, were 72.5% for Al2O3, 65% for CuO, and 62.8% for distilled water. Comparing the thermal efficiency at different flow rates, Al2O3 at 6 L/min, CuO at 6 L/min, and distilled water at 4 L/min showed high efficiencies; these results indicate that the Al2O3 nanofluid is the better choice for use as a heating medium for practical applications. [ABSTRACT FROM AUTHOR]

This paper discusses the effectiveness of simultaneous use of CuO nanofluid and air as a dual-fluid coolant for the thermal management of a photovoltaic/thermal (PV/T) system. Outdoor experimental studies were performed to calculate the discrepancies between indoor and outdoor test findings. The thermal efficiency and the electrical characteristics of the dual-fluid PV/T system were investigated under steady-state test conditions following ISO standards. It was found that the divergence in electrical efficiency between indoor and outdoor-based PVT testing was significantly higher, while the difference in thermal efficiencies was marginal. It was observed that nanofluid/air, even at the lowest flow rates, outclassed the water/air coolant at higher flow rates in terms of PV/T energy output, which also ultimately helps in reducing the energy requirement for pumping. Unlike conventional solar air heaters, the proposed dual-fluid PV/T system produces a high air temperature when operated with only air at stagnant nanofluid. The maximum PV/T efficiency of approximately 85% was recorded when the nanofluid and air flows were kept at 0.02 kg/s and 0.04 kg/s, respectively. It is concluded that outdoor steady state testing provides comprehensive performance characterization of the nanofluid powered dual-fluid coolant for the PV/T system. [ABSTRACT FROM AUTHOR]