Electrical Power Output Research Articles

Enhancing room temperature thermoelectric efficiency in zigzag phosphorene nanoribbon junctions through Quasi-Flat impurity bands

Abstract In this study, a novel approach has been utilized to Please specify the corresponding author.explore the room temperature thermoelectric properties of zigzag phosphorene nanoribbon-based monolayer-bilayer-monolayer junctions. To achieve thermoelectric properties at room temperature, a quasi-flat energy band with limited width is required. It has been demonstrated, for the first time, that such bands can be observed by considering a junction of the monolayer and bilayer phosphorene nanoribbons. By adjusting the ribbon widths, quasi-flat bands are produced. This geometrical problem is solved using analytical calculations for a general system and applied to phosphorene. We show that the edge states of phosphorene resemble a one-dimensional tight-binding system, with a close agreement between their results. Using the introduced approach, we calculate the electronic energy band structure of the specified system. Initially, we demonstrate that the formation of zigzag monolayer-bilayer-monolayer junctions can lead to the emergence of quasi-flat impurity bands within the energy bandgap. Furthermore, we show that utilizing these structures at room temperature, across a wide range of lead temperature differences, results in significant output electrical power and improved thermoelectric efficiency. The electrical power and thermoelectric efficiency are examined as functions of applied bias voltage and average chemical potential. Additionally, we explore how the output electrical power, thermoelectric efficiency, and efficiency at maximum power vary with the temperature difference between the leads at the ends of the structure.

Tapered curved-beam hinges for electret-based vibration energy harvesting devices

Abstract Interests on vibration energy harvesting have been growing recently for various applications. One of the major development goals for vibration energy harvesters has been improvement in energy conversion efficiency. To pursue that goal, one of the main approaches has been to broaden the spectra of harvesters. Employment of nonlinear springs, such as curved-beam hinges, has proven to be effective for that purpose. The main contribution of the current study is to introduce a lateral taper to the curved beam so as to further optimize the harvester performances. Via numerical analysis by using stochastic differential equations, the study shows that at 0.05g of vibration strength, tapered curved-beam hinges can result in higher electric power output than the non-tapered ones. Deformation-induced stress was taken into consideration as well, in reference to the fracture strength of the material (single-crystal silicon). At lower vibration strength (0.02g), spring nonlinearity becomes weaker, and as a result, the narrowest curved-beam hinge produces the highest output power. Overall, the current study demonstrates that tapering of the curved beam can be a useful addition in the vibration energy harvester design.

Effect of incomplete line defect size on energy localization and harvesting in phononic crystals.

The high electrical output performance of the phononic crystal (PnC)-based piezoelectric energy harvesting (PEH) system is of great research value in self-powered applications. This work presents the effect of incomplete line defect size on elastic wave energy localization and harvesting. The results show that for a given 7 × 5 supercell when the incomplete line defect reaches the second to sixth layer, the energy localization and harvesting performance show a changing trend of first increasing and then decreasing; when the incomplete line defect reaches the 4th, 5th, 3rd, 2nd, and 6th layers of the supercell, respectively, the performance of PEH systems shows a trend from large to small. Among them, when the incomplete line defect reaches the fourth layer of the supercell, the performance of the PEH system is optimal, and the maximum output voltage and the maximum output electric power are 22.54 V and 12.78 mW, respectively. This work provides valuable insights for improving the performance of PEH devices by using the PnC with incomplete line defects.

Performance assessment of hybrid adsorption/humidification-dehumidification desalination cycle powered by dish/stirling concentrated solar power system for sustainable freshwater production maximization

To achieve sustainable development, it is crucial to prioritize green polygeneration systems capable of generating diverse energy outputs, including electricity, heat, and distilled water, with enhanced efficiencies, reduced costs, and environmentally friendly advantages. Therefore, this study explores an innovative integration for a solar-powered desalination system to present an eco-friendly desalination system that agrees with sustainability goals of eco-friendly clean water and net-zero energy. The proposed system utilizes the waste heat from the solar dish Stirling power engine to drive the adsorption desalination system that is combined with two ejectors, humidification-dehumidification desalination. The humidification-dehumidification utilizes the waste energy from the silica gel-based adsorption desalination system process to enhance the freshwater productivity of the designed integrated system. Comprehensive modeling for the hybrid system components has been formulated using MATLAB to assess the electrical performance and freshwater production of the proposed system. The study also expresses the effect of evaporative-condenser heat recovery in enhancing the freshwater productivity of the hybrid system. Moreover, the effects of cycle time, and evaporator pressure on the performances of the system with and without heat recovery. The findings indicate that the proposed system has the capability to generate an electrical power output of approximately 23.42 kW, achieving a solar-to-electricity efficiency of 23.40 %. Moreover, the proposed system also produces a water production of 47.42 L/hr with a gained output ratio of 2.74. At the same time, the cost estimate revealed that the price of generated freshwater by the planned desalination facility utilizing the heat recovery loop was approximately 0.54 $/m3.

Different optical fiber hybrid repeater amplifiers arrangement for optical losses and optical dispersion management in the presence of modulation code schemes

Abstract This paper highlights the different optical fiber hybrid repeater amplifiers arrangement for optical losses and optical dispersion management in the presence of modulation code schemes. The light signal power is measured and clarified with/without any amplification versus fiber channel length with 1,300 and 1,550 nm wavelength based on various modulation schemes. Electrical output power after receiver is clarified without amplification and with various amplification techniques against fiber channel length with second and third wavelength based on on-off keying modulation code scheme. The quality factor and BER are measured after receiver against transmission data rates without amplification and with various amplification techniques against 300 km fiber channel length with 1,300 nm wavelength based different modulation code schemes.

Coupled theoretical modelling for the photoelectric performance by the concave-bent flexible PV module

Flexible PV module can fit with complex building skins and provide electricity for the building users. However, for the concave bent PV module, the special structure will cast shadow on itself, resulting in power loss during the working conditions, which is rarely investigated in previous studies. Combined optical-electrical-thermal model is decoupled to describe the realistic physical field and predict the concave module's electrical power output and working temperature. The beam shading ratio (BSR) and the diffuse shading ratio (DSR) are proposed based on the microfacet subdivision, which describes the real-time solar irradiance distribution and quantify the influence of self-shadow on the photoelectric performance by the concave-bent module under dynamic real-time working conditions. The concave PV module with the longitudinal/lateral layout is constructed and outdoor experiments are conducted to collect the data for the theoretical model verification. The parametric analysis is carried out to investigate the influence of inclination, curvature, and azimuth, demonstrating that increasing inclination and curvature angles raise power loss due to shading. Weather data of four cities are imported into the model to conduct annual performance simulation with longitudinal/lateral installation respectively. The model established in this paper has significant value for performance prediction in complex surface photovoltaic systems.

Sustainable desalination through hybrid photovoltaic/thermal membrane distillation: Development of an off-grid prototype

Global freshwater scarcity is a critical challenge, particularly severe in remote Australian communities where seawater intrusion and aquifer salinisation exacerbate the need for alternative water resources. Conventional desalination technologies are energy-intensive and unsuitable for rural areas. This study introduces a novel, off-grid, sustainable desalination solution utilising solar-integrated membrane distillation (MD) technology. An innovative, stand-alone prototype combining a hybrid photovoltaic/thermal (PV/T) system with direct contact MD (DCMD) has been designed and developed. This fully integrated PV/T collector efficiently supplies the thermal and electrical energy required for the MD process. The photovoltaic panel generates the necessary electrical energy, while the heat from the PV panel warms the MD system’s feed solution, enhancing overall efficiency through the solar cell cooling effect. In addition, an innovative fan-cooled radiator equipped with two DC fans with a low power consumption rating was designed and customized to be applied as MD system cooling medium within the outdoor setting. The concept development and feasibility of the system are explored in detail through a comprehensive experimental investigation employing an innovative and practical approach to design and examine the integrated hybrid solar MD unit. This unique system was designed, constructed, and tested under dynamic outdoor conditions, during the summer season in Melbourne, to assess the integration strategy and evaluate its long-term operational performance. The performance of the integrated PV/T-MD system was evaluated using two commercial hydrophobic membranes with different pore sizes under various outdoor conditions and PV/T fluid flow rates. Key performance metrics analysed include solar irradiance intensity, temperature profiles of the PV/T panel and MD module, power, current and voltage profiles of the unit components, permeate flux, specific water productivity (SWP) and the thermal (ηthermPV/T) and electrical (ηelecPV/T) efficiencies, along with the gained output ratio (GOR). Comprehensive experimental assessments in indoor and outdoor settings were undertaken to confirm the technical viability of the system. The study demonstrates the feasibility of such systems through real-world trials and addresses key challenges in energy efficiency and internal heat recovery. The experimental trials demonstrated permeate flux values ranging between 8–16 kg/m2h outdoors, compared to 22–30 kg/m2h indoors, reflecting the impact of fluctuating environmental conditions. The system’s power consumption was measured 130–140 W, about one-third of the PV/T power rating. The maximum power generation reached 280 W in battery charging mode. achieving a maximum ηthermPV/T of 20 % and an ηelecPV/T of 18 %. Additionally, the cooling effect of the PV/T panel resulted in a 1.5–2 °C temperature reduction, improving electrical power output by 0.8–1.2 %. The findings highlight the significant potential of the system in providing reliable and efficient freshwater production in remote, off-grid communities, offering a scalable solution to address global water scarcity challenges.

An enhanced broadband piezoelectric energy harvester via elastic amplification structure for multidirectional vibration

Abstract Vibration energy harvesting using a piezoelectric mechanism has significant potential for powering wireless sensors. However, most current vibration energy harvesters face limitations such as bidirectionality, narrow bandwidth, and high operating frequencies. To address these issues, we propose an enhanced broadband piezoelectric energy harvester utilizing an elastic amplification structure for multidirectional vibration (EB-PVEH). By utilizing the multidirectional rotation capacity of the excitation block and the amplified foundation excitation provided by springs, the EB-PVEH effectively captures broadband vibrations in 2D space under low-frequency excitation. Additionally, its design features long-term durability, as the piezoelectric beams are smoothly excited by the pendulum-induced motion of the block without a tip mass. The practical feasibility and the impact of structural parameters on the output behavior of EB-PVEH were investigated through theoretical analysis and experimental testing. The results revealed that the introduction of springs dynamically amplified the harnessed electrical power output. Moreover, EB-PVEH could harvest the multidirectional vibration, and it exhibited different power-generating characteristics in various directions. Furthermore, the resonance frequency could be efficiently tuned by adjusting the flexible arm length and proof mass, with different optimal arm lengths identified for each vibration direction to maximize working bandwidth. The harvester achieved an optimal output power of 3.98 mW. Practical applications, such as charging a capacitor by driving an e-bike or a bike, demonstrate the potential of the proposed harvester to provide power for micro-electrical devices.

UJI EKSPERIMEN PENGARUH JUMLAH SUDU DAN DEBIT TERHADAP DAYA DAN EFISIENSI TURBIN AIR TIPE VORTEX

<p class="StyleAuthorBold"><em>The electrification ratio in Indonesia is currently still 87%. This means that there are still 8.5 million residents or the equivalent of 2500 villages that have not received electricity. Indonesia has a lot of potential for renewable energy such as water energy. 7 GW capacity from renewable energy, 66% of which comes from hydropower. The manufacture of pico-hydro scale power plants can be a cheap alternative. Pico-hydro can be applied to irrigation canals so that it can produce small-scale electrical energy. One type of water turbine that can be utilized is a vortex type water turbine. The study used experimental methods. The independent variables are variations in the number of blades 2, 4, and 6 and the distance between the blades and the outlet is 1 cm. The dependent variable of the research is the power and efficiency produced by the vortex water turbine. The data analysis technique in this study used quantitative descriptive analysis techniques. The basin used is a conical basin type with the upper diameter is 40 cm, the lower/oulet diameter is 6.5 cm, and the height is 32 cm. The water discharge in this test has 7 variations, that is 1,12 l/s, 1,26 l/s, 1,54 l/s, 1,68 l/s, 1,82 l/s, 1,96 l/s, and 2,11 l/s. This test produced the highest electrical output power of 9.66 Watts, at a total of 2 blades, the discharge is 1,86 l/s. At the number of blades 6 at a discharge of 1.96 l / d is the highest efficiency value of 6.3%.</em></p>

Thermal management enhancement of building-integrated photovoltaic systems using coupled heat pipe and evaporative porous clay cooler

The building-integrated photovoltaic (BIPV) panel systems often lead to a notable decline in PV panels efficiency and lifetime due to their temperature rise because of inadequate cooling. This study investigates the performance of innovative cooling strategy of using a coupled heat pipes and porous clay cooler and compare it with other related three BIPV cooling systems configurations including a conventional BIPV cooling with and without air gap and a pure evaporative porous clay cooling. The aim is to improve the PV panel cooling, ultimately reduce the PV temperature and enhance the overall performance of the BIPV system as well as reducing the building indoor temperature and boosting energy efficiency within the building. The system model, comprising sets of transient equations for the different system configurations, was solved using MATLAB and confirmed with previous experimental findings. The results indicate that comparing with the traditional BIPV system, using BIPV/Clay cooling systems and the hybrid BIPV/Clay-heat pipe cooling systems achieved peak PV temperature reductions of up to 14 °C and 14.7 °C, respectively. Additionally, these cooling methods led to a maximum interior room temperature reduction of approximately 14 °C and an average decrease of 8 °C. Moreover, the hybrid BIPV/Clay-heat pipe cooling system demonstrates superior performance compared to traditional BIPV system, achieving the highest improvements in PV electrical efficiency, output power, and exergy efficiency, with gains of 7.8 %, 6.4 %, and 8.4 %, respectively. Further, when the hybrid BIPV/Clay-heat pipe cooling system was employed, the clay cooling efficiency and clay exergy efficiency values improved on average by 30.2 % and 29.7 %, respectively, compared to the BIPV/Clay cooling system in addition to the increase of the lifetime of the PV panels due to isolating it from the contact with the water/water vapor of the clay cooling system. However, this hybrid approach resulted in a rise in electricity production costs from 0.077 $/kWh to roughly 0.138 $/kWh and extended the payback time from 7.38 years to 13.6 years. But, despite its initial economic drawbacks, the hybrid BIPV/Clay-HP cooling system demonstrates considerable effectiveness and long lifetime compared to other cooling configurations.

Contribution of transient heat transfer to overpressure protection in a passive Boiling Water Reactor

The BWRX-300 reactor is a small modular reactor with 300 MW nominal electric power output. As the abbreviation indicates, the reactor is a boiling type reactor using water as the coolant. The main operating principle of the reactor model is the use of natural circulation of the coolant for both steady-state operation and emergency cooling of the reactor. Isolation Condenser Systems (ICS) have been used in early BWRs and were reintroduced in the 1990s to implement passive safety.Modern technologies enable effective simulation of objects of various complexity. In this study, the thermal-hydraulic system code TRACE v.5 is used to simulate BWRX-300 reactor plant operation. The software enables calculation of a system consisting of the reactor pressure vessel and ICS in both steady-state and transient operation.The ICS is an emergency cooling system borrowed from the previous generation of GE Hitachi BWRs, the ESBWRs, and it consists of a vertical tube bundle heat exchanger immersed in a water tank. Although this system design remains unchanged, its purpose is different. The BWRX-300 design completely eliminates safety and relief valves. This is why the ICS must perform both overpressure protection and long term heat dissipation functions.Three reactor plant operation states were simulated: normal operation with nominal parameters; reactor isolation; and the transient process into the cooling down mode by reactor shutdown and ICS activation. The results demonstrate that the ICS is capable to mitigate overpressure transients. Upon ICS startup, its metallic structures absorb heat well in excess of its nominal steady-state rating. Initial thermal inertia of the system is important for overpressure mitigation in transients.

Development of a Power Conversion System for a Wave Energy Converter connected to the Electrical Network

Abstract Global efforts are focused on promoting a sustainable energy supply by increasing the use of renewable energies and decreasing reliance on conventional sources. Among renewable sources, Wave energy is a promising one, but it is still widely untapped worldwide. In the current energy context, it is crucial to synchronize the characteristics of renewable sources with the needs of the existing electrical network which is undergoing a deep change towards the smart grid paradigm. Power electronic converters, as interface devices, play a fundamental role in facilitating the transfer of renewable energy to the electrical network. For this reason, this study focuses on the design and optimization of an electrical power conversion system for a wave energy converter (WEC) coupled with a hydraulic power take-off. This electrical power conversion system allows the WEC to connect to the electrical network and deliver a smooth output electrical power. Indeed, thanks to a particular control system, the conversion from mechanical power to electrical power is achieved with losses of less than 5% in regular sea state conditions

Techno-economic viability of sustainable solar co-generation using CPV cells in parabolic dish concentrators: A 20-year perspective

Solar co-generation is a cutting-edge technology that enables the instantaneous production of electricity and heat energy by employing concentrated solar power (CSP) systems. This study presents the development and experimental analysis of a novel small-scale solar co-generation system, utilizing concentrated photovoltaic (CPV) cells integrated into a solar paraboloidal dish concentrator (SPDC) for simultaneous electricity and heat production. The system, designed with a high concentration ratio, employs a CPV module composed of four 1 cm × 1 cm cells mounted on a flat receiver of a parabolic dish concentrator with an aperture area of 12.6 m2. Experimental results, obtained over three consecutive days, demonstrate that the CPV module achieves an electric power output ranging from 480 to 645 W daily, while the SPDC system generates thermal energy between 395 and 725 W. The economic analysis indicates a cost of ₹10.75 per unit of electricity, with a payback period of approximately 13.5 years, assuming a 20-year system lifespan. Additionally, the reliability of the CPV module and the impact of varying encapsulation materials were critically assessed, providing insights into potential improvements and long-term performance. The findings underscore the viability and economic potential of solar co-generation systems employing CPV technology, contributing to the advancement of sustainable energy solutions.

Implementasi Metode Artificial Bee Colony Untuk Penempatan Distributed Generator Pada Penyulang Rayon Tanjung

Distributed Generation (DG) is a power plant that is spread over the power distribution network. In principle, electrical power output is generated by power plants located far from the load center and electrical power is transmitted to the load center through transmission and distribution networks. The longer the cable from the power plant or substation, the lower the voltage at the end load. Sub-optimal DG placement and size can result in increased power losses and affect the system voltage profile. In addition, suboptimal generation capacity can lead to voltage instability, reduced system security, and potential impacts on system frequency and emissions. Therefore, this study will use the Artificial Bee Colony (ABC) method to determine the optimal DG capacity and location. In the base case condition, the power losses in the system are 118 KW and 99 Kvar. Power losses after the installation of 1 DG active power loss becomes 37.4 KW and reactive power loss becomes 31.65 Kvar. Placement of 2 DGs reduces active power loss to 17 KW and reactive power loss to 15 Kvar. While the placement of 3 DG reduces active power loss to 33 KW and reactive power loss to 28 KVar.

Thermal Analysis of Photovoltaic Panel Cooled by Electrospray Using Different Fluids

In this study, the cooling performance of the photovoltaic (PV) panel was examined by the electrospray cooling method. The experiments were carried out under 1000 W/m² irradiation, 25 G nozzle diameter and 70 mm nozzle-to-PV panel distance and 20 kV voltage. Water, ethanol and water - ethanol (50%- 50%) mixture were atomized and sprayed on the panel surface at flow rates of 50-80-110 ml/h. The results showed that electrical power output decreased with increasing PV panel surface temperature. Ethanol and water - ethanol mixture showed a more effective cooling performance than water, especially at flow rates of 80 and 110 ml/h. At the highest flow rate, ethanol reduced the panel temperature by 59%, providing 6,8% more electrical power output than the uncooled condition. These findings show that the electrospray cooling method is effective in increasing the electrical efficiency of PV panels and that better cooling performance is achieved with ethanol, water - ethanol mixture compared to water.

The efficient strategy of operating the active cooling systems incorporated with photovoltaic panels for the three climatic regions: A case study

ABSTRACT Photovoltaic stations in Algeria are considered an effective solution to overcome the problem of its lack of electrical power and achieve the goals of sustainable development. The weather in Algeria is continental, it has three main climate zones from north to south, and the climate in Algeria is desert, which causes an increase in the temperature of photovoltaic modules and thus a decrease in their production of electrical power. Then the active cooling systems that use water as a cooling medium represent a good option to reduce the PV module temperature and thus increase electrical power generation rates. Due to the change in weather in Algeria from north to south and during the four seasons, in some periods, the operation of cooling systems is ineffective and leads to a decrease in the net output electrical power of photovoltaic stations. Therefore, this manuscript aims to develop an advanced strategy for operating active cooling systems incorporated with PV stations to achieve the highest net electrical power output from PV stations in Algeria. To achieve this goal, the theoretical study was conducted on three different regions in Algeria that express its continental climate, namely, Algiers (36°46′ N, 3°03′ E), northern Algeria, and Djelfa (34°40′ N 3°15′ E) in central Algeria and Ghardaïa (32°29′ N 3°40′ E) in southern Algeria, to get the optimal cooling strategies that achieve the highest net electrical power produced by PV stations. The simulation results presented that the average improvement in the electrical power generated from the PV panels incorporated with active cooling systems reached 15.1%, 17.8%, and 19.7% under the climate conditions of Algiers, Djelfa, and Ghardaïa, respectively. The optimal operating strategies of active cooling systems integrated with PV stations in Algeria increase the average net output electrical power of the PV stations by a rate reached 7.65%, 7.13%, and 4.91% for Algiers, Djelfa, and Ghardaïa, respectively.

Home energy management system for residential fuel cell-based combined heat and power system

The goal of this paper is to propose an optimization scheme for enhancing power dispatch and load scheduling for residential fuel cell-based combined heat and power systems (FC-CHPS) using mixed integer linear programming (MILP), considering the lifetime degradation of both the fuel cell system (FCS) and battery energy storage systems (BESS). The scheme is applied in the home energy management system that oversees the electric and thermal power of residential FC-CHPS. First, the nonlinearity in the relationship between the natural gas consumption and output electric power, and between the residual thermal power and output electric power of the fuel cell system (FCS) in the FC-CHPS is approximated using piecewise linearization. Then, the piecewise linearization is integrated with MILP to derive optimal power dispatch and load scheduling solutions, while accounting for the nonlinearity of the FCS. Next, cost functions representing the lifetime degradation of FCS and BESS are formulated. These cost functions result in nonlinear optimization constraints. Therefore, innovative methods are proposed to linearize these constraints, allowing the continued use of MILP as the optimization method and factoring in the lifetime degradation of FCS and BESS. Compared to the mixed-integer non-linear programming (MINLP) method that does not linearize the non-linearity in the FCS or the lifetime degradation of the FCS and BESS, the proposed MILP scheme achieves the identical objective function value. Furthermore, the computation time for the proposed MILP scheme is 99.94 % lower than that required by the MINLP method. The proposed scheme provides accurate results in short computation times.

A Hybrid Prediction Model for Short-Term Load Forecasting in Power Systems

Short-term load forecasting (STLF) plays a vital role in effective power system management by assisting power dispatch centers in developing generation plans and ensuring smooth system operation. This study introduces a novel hybrid prediction model called iSSA-LSSVM to tackle the STLF challenge. By integrating the Salp Swarm Algorithm (SSA) with Least Squares Support Vector Machines (LSSVM), the iSSA-LSSVM model significantly improves LSSVM's prediction accuracy. One of the key contributions is the model's ability to autonomously ne-tune LSSVM hyperparameters, eliminating the need for manual adjustments and optimizing performance. Modifying the SSA within iSSA-LSSVM enhances the original algorithm's exploration and exploitation capabilities, ensuring better search efficiency and precision. Using a dataset with four independent variables as input and electrical power output as the target variable, the model demonstrates superior predictive performance. Comparative analysis with three other models shows that iSSA-LSSVM achieves a lower Mean Square Error (MSE) and faster convergence. This improvement in accuracy and efficiency enhances STLF, allowing power dispatch centers to develop more precise generation plans and ensure more reliable power system operation.

Understanding Solid Oxide Fuel Cell Hybridization: A Critical Review

A holistic literature review of 399 articles is presented on hybrid solid oxide fuel cell (SOFC) systems and taxonomized through a unique classification methodology that considers primary energy sources, component configurations, system outputs and relevant analysis. In the reviewed research articles, primarily four different types of technologies are used to complement the energy production of the fuel cell stack. As a result, four respective categories were established in terms of the coupling components, inclusive of (1) wind turbines (WTs), (2) solar systems (SS), (3) thermal power plant turbines (TPPTs) and (4) piston engines (PEs). Additional classification was needed to further subdivide the evaluated system configurations, due to the wide spectrum of system outputs encountered in the reviewed literature. That involved (a) electrical power generation (PG), (b) four types of cogeneration (CG), (c) four types of trigeneration (TG) and (d) two types of multigeneration (MG). Depending on the type of assessment in respective research, literature was further categorized as computational, experimental, or both computational and experimental. The most prevalent hybrid system amongst the 102 designs, as adapted from the reviewed literature, is the SOFC/gas turbine (GT) application, with the overwhelming majority producing exclusively electrical power output. The particular system is physically demonstrated in an existing 220-kW experimental facility established by the National Fuel Cell Research Center (NFCRC). The identified systems were predominantly computationally examined and research focused on operating conditions around specific design load ratings. Energy, exergy, economic, and environmental assessments were typically followed by sensitivity studies in the reviewed literature. The primary decision variables in most cases revolved around SOFC operating conditions, such as temperatures over 1000 °C as well as elevated pressures. Those resulted in the deterioration of the electrochemical cell and failed to be addressed by the majority of encountered studies. Improvements in the conversion efficiency of PG applications were enabled by natural gas (NG)-fed pressurized SOFCs, directly coupled to GTs. The most efficient power configuration in terms of thermodynamic performance was achieved by coupling PEs to SOFCs and a metal hydride reactor (MHR) to unlock a maximum net system efficiency of 79.54%. CG systems integrating solar cells (SCs) and photovoltaic panels (PVs) to SOFC subsystems can result in a combined efficiency of approximately 90% and sustain this over a broad energy demand range. TG systems incorporating gasifiers to SOFC/GT subsystems achieved a combined efficiency of 93%, whereas the optimal combined efficiency in MG configurations was identified at 79.5% by coupling SCs to the SOFC/GT/organic Rankine cycle turbine (ORCT) subsystems. In terms of cost-effectiveness, configurations that relied on increasing levels of renewable energy (RE) technologies resulted in high overall levelized cost of electricity (LCOE). This cost was increased further when power storage units were deployed to address wind and solar intermittency challenges. Configurations classified under TPPTs operating on low carbon-content fuels were preferred in terms of providing lower LCOE, while applications operating on gasified biomass and coal blends should deploy additional CO2 capture and storage units to mitigate respective emissions.

Building Energy Savings and Power Output Augmentation of Roof Mounted PV Using Co-Located Rooftop Reflectors

Abstract Photovoltaic panels (PVs) installed on building rooftops yield a positive influence on the thermal performance of the building due to the shading of the PV panels, decreasing cooling loads while causing a smaller increase in heating loads. Additionally, the electrical power output of PV panels has been shown to be increased by including reflectors between PV rows, concentrating the solar flux onto the active portion of the panels. When implemented into the spaces between the rows of a roof-mounted PV array, reflectors might further improve the positive thermal effects of rooftop installed PV arrays. This work focuses on predicting rooftop heat flux and temperature for a building rooftop equipped with PV panels and reflectors. The Saved Energy Load (SEL), Additional Energy Load (AEL), PV power output, rooftop heat flux and the utility factor (ratio of positive building energy impacts to negative building energy impacts) are reported parametrically for variations in the rooftop absorptivity and reflector area for three United States locations. Utility factors of 375, 140 and 160 are found for Phoenix, Boise and Dayton, respectively, for a reflector covering the full area between panels with a roof having a minimal absorptivity. A building in Phoenix exhibits a 15% increase in the utility factor of the PV-building system when reflectors are incorporated compared against a PV-building system without reflectors, while a building in Dayton showed a 22% increase in utility factor when reflectors are included between the rows of a roof-mounted PV array.