Devices For Electricity Generation Research Articles

Performance evaluation and parametric analysis of nighttime electricity generation system integrating thermogalvanic cells with radiative sky cooling

While distributed power generation has been made possible by photovoltaic cells during the day, there is no comparable option available at night, especially in off-grid areas around the world. In our work, a cost-effective nighttime electricity generation approach based on thermogalvanic cells and radiative sky cooling is proposed. Based on the developed thermal and electrical coupled model, we determine the maximum power point and optimal operating conditions, including the optimal load ratio of 1.2 and area ratio of 1. The calculated results show that, with systematic optimization, a high power density of 900 mW/m2 is achievable for the device by enhancing (suppressing) heat transfer between the hot (cold) side and ambient air, operating at hot and dry conditions, and optimizing the geometry of individual cells. Furthermore, the presented device significantly outperforms the nighttime thermoelectric generator and could directly power various electric devices to meet the power needs of people in remote or off-grid regions. This work identifies how to achieve maximal electrical power generation for nighttime radiative-cooling-assisted thermogalvanic devices, providing a feasible approach for constructing high-performance nighttime electricity generation devices.

Solvothermal synthesis of hybrid nanoarchitectonics nickel-metal organic framework modified nickel foam as a bifunctional electrocatalyst for direct urea and nitrate fuel cell

Urea and nitrate-based fuel cells have emerged as promising electricity generation devices. However, most of these catalysts are expensive and limited in supply, which limits their practical applications. Hence, metal-organic frameworks (MOF) have been explored as catalysts due to their low cost, easy preparation, and high redox activity. Here, we synthesize nickel-based MOF (Ni-MOF) via one-pot solvothermal technique as bifunctional electrocatalyst for the direct urea and nitrate fuel cell. The as-synthesized Ni-MOF is deposited on nickel foam (NF) and used as working electrode (Ni-MOF/NF) which demonstrates a peak current density of 188 mA/cm2 for urea oxidation reaction (UOR) and −14 mA/cm2 for nitrate reduction reaction (NRR) at an onset potential of ∼ 1.58 V (vs RHE), and ∼ 1.12 V (vs RHE), respectively The enhanced functionality of the Ni-MOF/NF electrode can be attributed to the high catalytic efficacy of the Ni-MOF. This is mainly due to the presence of multiple oxidation states of N (i.e., Ni2+/3+) and excellent electronic conductivity of the organic ligands in MOF structure. Moreover, Ni-MOF/NF electrodes retain ∼ 71.2% and ∼ 83.9% capacity after 20000 s of UOR and NRR, respectively. This efficacy of the as-fabricated electrocatalyst proves MOF as a promising platform for direct fuel cell applications.

Structural, Thermal, and Electrical Properties of Poly(Ethylene Oxide)-Tetramethyl Succinonitrile Blend for Redox Mediators.

An all-solid–state dye-sensitized solar cell is one of the non-fossil fuel-based electrochemical devices for electricity generation in a high-temperature region. This device utilizes a redox mediator, which is a fast ion-conducting solid polymer electrolyte (SPE). The SPE makes the device economical, thinner, and safer in high-temperature regions. The SPE generally has a form of matrix−plasticizer−redox salts. Succinonitrile (SN) is generally employed as a plasticizer for reducing the crystallinity of poly(ethylene oxide), abbreviated as PEO, a common polymeric matrix. In the present paper, the structural and thermal properties of tetramethyl succinonitrile (TMSN) were compared with SN for its application as a solid plasticizer. TMSN and SN both are plastic crystals. TMSN has four methyl groups by replacing the hydrogen of the SN, resulting in higher molecular weight, solid–solid phase transition temperature, and melting temperature. We thoroughly studied the structural, thermal, and electrical properties of the [(1−x)PEO: xTMSN] blend for utilizing it as a matrix, where x = 0–0.25 in mole fraction. The FT-IR spectra and XRD patterns of the blends exhibited PEO-alike up to x = 0.15 mole and TMSN-alike for x > 0.15 mole. Differential scanning calorimetry revealed formation of a eutectic phase from x = 0.1 mole and phase separation from x = 0.15 mole. The blends with x = 0.1–0.15 mole had a low value of PEO crystallinity. Thermogravimetric analysis showed thermal stability of the blends up to 75 °C. The blends exhibited electrical conductivity, σ25°C more than 10−9 S cm−1, and Arrhenius behavior (activation energy, ~0.8 eV) in a temperature region, 25–50 °C.

Simultaneous Solar‐driven Steam and Electricity Generation by Cost‐effective, Easy Scale‐up MnO2‐based Flexible Membranes

Harvesting solar energy in an effective manner for steam and electricity generation is a promising technique to simultaneously cope with the energy and water crises. However, the construction of efficient and easy scale‐up photothermal materials for steam and electricity cogeneration remains challenging. Herein, we report a facile and cost‐effective strategy to prepare MnO2‐decorated cotton cloth (MCx). The wide adsorption spectrum and excellent photothermal conversion ability of the in situ‐formed MnO2 nanoparticles make the MCx to be advanced photothermal materials. Consequently, the hybrid device integrated with MCx as the photothermal layer and the thermoelectric (TE) module for electricity power conversion exhibits an extremely high evaporation rate of 2.24 kg m−2 h−1 under 1 kW m−2 irradiation, which is ranked among the most powerful solar evaporators. More importantly, during solar evaporation, the hybrid device produces an open‐circuit voltage of 0.3 V and a power output of 1.6 W m−2 under 3 Sun irradiation, and outperforms most of the previously reported solar‐driven electricity generation devices. Therefore, the integrated device with synergistic solar‐thermal utilization opens up a green way toward simultaneous solar vapor and electric power generation in remote and resource‐constrained areas.

Polyaniline interweaved iron embedded in urea–formaldehyde resin-based carbon as a cost-effective catalyst for power generation in microbial fuel cell

• Iron-containing urea–formaldehyde (Fe-UF) resins were used as precursors. • Polyaniline (PANI) interweaved Fe-UF was pyrolyzed for the synthesis of PANI@Fe/NC. • Polyaniline interweaving improved the conductivity, charge transfer resistance, and ORR activity over Fe/NC. • Among the catalysts, PANI@Fe/NC achieved the highest power output of 637.53 mW m −2 . Microbial fuel cells (MFCs) have emerged as promising renewable electricity generation devices. However, the technology is challenged by poor durability, sluggish oxygen reduction reaction (ORR) kinetics, and high capital cost. Herein, we developed highly efficient and inexpensive electrocatalysts for commercially viable MFCs. The performance of the fabricated air-cathodes (NC, Fe/NC, and PANI@Fe/NC) was systematically evaluated in single-chamber MFCs with activated sludge as inoculum. Fe containing urea–formaldehyde (UF) resins were interweaved with polyaniline to enhance overall conductivity, charge transfer, and power generation in MFCs. PANI interweaved resins exhibit nanofiber aggregation, which on pyrolysis at 800℃ result in unique coralline-like short rods attributing to the large surface area of PANI@Fe/NC. The electrochemical analysis highlighted the superior performance of PANI@Fe/NC with a peak reduction current of −0.214 mA, charge transfer resistance (Rct) of 132.5 Ω, and improved ORR activity. PANI@Fe/NC achieved the highest power output (637.53 mW m -2 ) achieved by PANI@Fe/NC was 36.25% higher than conventional 10 wt% Pt/C (467.92 mW m -2 ). A high current density of 1943.71 mA m -2 compared to 1665.18 mA m -2 for Pt/C is indicative of the significant improvement in the catalytic ability of PANI@Fe/NC. This could be attributed to diverse Fe and N states in the carbon composites and the large surface area available for high active site density. The outcomes suggest that this novel and cost-effective cathode catalyst could be used for long-term fuel cell and related applications.

Вплив швидкості потоків модельного палива та окисника на електричні властивості керамічних паливних комірок

Fuel Cells are one of the most efficient and environmentally friendly devices for electricity generation, which are developing rapidly and are already in the early stages of commercialization. Solid Oxide Fuel Cells (SOFC) areone of the most promising their types due to the highest efficiency, fuel flexibility (H2, CnHm, CO etc.) and no needs in platinum group catalysts. The performance of SOFC is affected by various polarization losses, which aredependant on selected materials, their structure and SOFC operation parameters. Over the last decade, much attention is given to the study of SOFC’s electrochemical properties at different operating regimes: temperatures, fuels, fuel and oxidantflow rates etc. The work is devoted to studying the influence of the model fuel (5% H2—Ar) and air (oxidant) flow rates on electrical properties of Solid Oxide Fuel Cellat 800 °C to determine the best combination of gas flow rates, which provide the maximum values of specific electric power. The fuel (0,35 l/min) and oxidant (1 l/min)flow rates was found as the optimal operation regime of fuel and air supply for the SOFC tested. The highest electrical densityto be ensured by the model fuel was determined as 34 mW/cm2. The amount / flow rate of oxidant and fuel gases supplied to the fuel cell does not correspond to the ratio of the reagents of the chemical reaction of oxidation of the fuel. This difference is explained by the fact that the SOFC effectiveness of fuel and oxidant utilization depends not only from to the properties structure and materials of each components: anode, cathode, electrolyte, but also from concentration of fuel and oxidant in model fuel or air, which also creates a barrier for oxidant and fuel molecules to reach the reaction zone. Keywords: Solid Oxide Fuel Cell, electrical properties, fuelgasmixtures, hydrogen, oxidant.

Renewable electricity generation for off grid remote communities; Life Cycle Assessment Study in Alaska, USA

Many remote communities are reliant on fossil fuels to produce electricity and/or heat. The environmental impact from these generation systems in remote regions have significant emissions from the transportation of fuel to the generation site and only exacerbate the effects of climate change on these communities. Power via sustainable methods is a priority to avoid further environmental damage and sustain local communities (aligns with UNSDG 7, 11 and 13).A life cycle assessment for the deployment of a renewable electricity generation device (ORPC, Rivgen®) in Alaska, USA as a case study comparison against the existing diesel electricity generation method was analysed using ReCiPe methodology . The kg CO2 eq/MWh is shown to decrease from 1345.45 kg CO2 eq/MWh with diesel electricity generation to 17.49 kg CO2 eq/MWh after a 20-year Rivgen® deployment. The impact of operations and maintenance is minimised if local operators service the device instead of OEMs, with an additional saving of between 0.03 and 25.50% across environmental impact categories. Although the marine hydrokinetic device is less environmentally harmful compared to diesel electricity generating sets, optimal deployment of the device is required to overcome some environmental burdens; agricultural land occupation, water depletion and metal depletion.The results demonstrate that deployment of renewable electricity generation devices to off grid remote locations for electricity generation can have the same or less, environmental impact as urban grid systems.

Recent Development of Electrocatalytic CO2 Reduction Application to Energy Conversion.

Carbon dioxide (CO2 ) emission has caused greenhouse gas pollution worldwide. Hence, strengthening CO2 recycling is necessary. CO2 electroreduction reaction (CRR) is recognized as a promising approach to utilize waste CO2 . Electrocatalysts in the CRR process play a critical role in determining the selectivity and activity of CRR. Different types of electrocatalysts are introduced in this review: noble metals and their derived compounds, transition metals and their derived compounds, organic polymer, and carbon-based materials, as well as their major products, Faradaic efficiency, current density, and onset potential. Furthermore, this paper overviews the recent progress of the following two major applications of CRR according to the different energy conversion methods: electricity generation and formation of valuable carbonaceous products. Considering electricity generation devices, the electrochemical properties of metal-CO2 batteries, including Li-CO2 , Na-CO2 , Al-CO2 , and Zn-CO2 batteries, are mainly summarized. Finally, different pathways of CO2 electroreduction to carbon-based fuels is presented, and their reaction mechanisms are illustrated. This review provides a clear and innovative insight into the entire reaction process of CRR, guiding the new electrocatalysts design, state-of-the-art analysis technique application, and reaction system innovation.

Experimental Comparison of Energy Generation between Conventional and Wavy Leading Edge Blades in HAWT

Horizontal Axis Wind Turbine (HAWT) is one of the most important devices for electricity generation from Wind Energy, and design of new blades has become a fundamental research field to improve the efficiency and to reduce cost of this system. This article presents a preliminary comparison between two micro Wind Turbines (WT), one with standard blades and another one with Wavy Leading Edge (WLE) morphology, inspired by the flippers of the humpback whale, to work at low-speed wind conditions. To perform a correct validation, the authors propose a four steps approach for the design, manufacture and test of a WT. First, the design of the blade, followed by the design of the Wind Turbine (WT). Next step is the manufacture of two functional models, one with WLE and another with standard blades, to make a relative comparison, and, finally, the acquisition of real-time data from these systems for the corresponding analysis in terms of energy generation. Results show that the WLE has an increase of over 20% in energy production in all the tests that were performed, with respect to the standard blade.

H2/O2enzymatic fuel cells: from proof-of-concept to powerful devices

H2/O2enzymatic fuel cells are sustainable devices for electricity generation that have undergone great developments during the last 5 years, thanks to the concomitant improvement of the involved enzymes,i.e.hydrogenases and bilirubin oxidase, and their immobilization procedure on electrodes.

Analysis of PV/wind potential in the Canadian residential sector through high-resolution building energy simulation

Rising fuel prices and global warming are two major issues that concern people today. In this paper, the effect that the integration of the hybrid photovoltaic (PV)/wind-turbine generation can have on conservation of energy and reduction of greenhouse gases (GHGs) has been studied. Base-case energy demands were calculated using building energy simulation software and then the residential buildings were equipped with the PV/wind-turbine electricity generation devices. The results show that the integration of those equipments can reduce both cost of fuel and GHG emissions to a fair amount. Copyright © 2008 John Wiley & Sons, Ltd.

A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films

THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods1. Here we describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency. The device is based on a 10-µm-thick, optically transparent film of titanium dioxide particles a few nanometres in size, coated with a monolayer of a charge-transfer dye to sensitize the film for light harvesting. Because of the high surface area of the semiconductor film and the ideal spectral characteristics of the dye, the device harvests a high proportion of the incident solar energy flux (46%) and shows exceptionally high efficiencies for the conversion of incident photons to electrical current (more than 80%). The overall light-to-electric energy conversion yield is 7.1-7.9% in simulated solar light and 12% in diffuse daylight. The large current densities (greater than 12 mA cm-2) and exceptional stability (sustaining at least five million turnovers without decomposition), as well as the low cost, make practical applications feasible.

Comparison based on energy and exergy analyses of the potential cogeneration efficiencies for fuel cells and other electricity generation devices

Comparisons of the potential cogeneration efficiencies are made, based on energy and exergy analyses, for several devices for electricity generation. The investigation considers several types of fuel cell systems (Phosphoric Acid, Alkaline, Solid Polymer Electrolyte, Molten Carbonate and Solid Oxide), and several fossi-fuel and nuclear cogeneration systems based on steam power plants. In the analysis, each system is modelled as a device for which fuel and air enter, and electrical- and thermal-energy products and material and thermal-energy wastes exit. The results for all systems considered indicate that exergy analyses should be used when analysing the cogeneration potential of systems for electricity generation, because they weigh the usefulnesses of heat and electricity on equivalent bases. Energy analyses tend to present overly optimistic views of performance. These findings are particularly significant when large fractions of the heat output from a system are utilized for cogeneration.