A review of integration strategies for solid oxide fuel cells

Due to increasing oil and gas demand, the depletion of fossil resources, serious global warming, efficient energy systems and new energy conversion processes are urgently needed. Fuel cells and hybrid systems have emerged as advanced thermodynamic systems with great promise in achieving high energy/power efficiency with reduced environmental loads. In particular, due to the synergistic effect of using integrated solid oxide fuel cell (SOFC) and classical thermodynamic cycle technologies, the efficiency of the integrated system can be significantly improved. This paper reviews different concepts/strategies for SOFC-based integration systems, which are timely transformational energy-related technologies available to overcome the threats posed by climate change and energy security.     

Applications of porous media combustion technology – A review

The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The porous medium combustion (PMC) has proved to be one of the feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This article provides a comprehensive picture of the global scenario of applications of PMC so as to enable the researchers to decide the direction of further investigation. The works published so far in this area are reviewed, classified according to their objectives and presented in an organized manner with general conclusions.     

A review on the mechanical and electrical properties of graphite and modified graphite reinforced polymer composites

Carbon materials particularly in the form of sparkling diamonds have held mankind spellbound for centuries, and in its other forms, like coal and coke continue to serve mankind as a fuel material, like carbon black, carbon fibers, carbon nanofibers and carbon nanotubes meet requirements of reinforcing filler in several applications. All these various forms of carbon are possible because of the element's unique hybridization ability. Graphene (a single two-dimensional layer of carbon atoms bonded together in the hexagonal graphite lattice), the basic building block of graphite, is at the epicenter of present-day materials research because of its high values of Young's modulus, fracture strength, thermal conductivity, specific surface area and fascinating transport phenomena leading to its use in multifarious applications like energy storage materials, liquid crystal devices, mechanical resonators and polymer composites. In this review, we focus on graphite and describe its various modifications for use as modified fillers in polymer matrices for creating polymer-carbon nanocomposites.     

抗静电TPV/MB-CNTs共混改性材料的研究

研究了碳蚋米管母料(MB-CNTs)改性硫化热塑性弹性体(TPV)的抗静电性能.结果表明,碳蚋米管(CNTs)可明显改善TPV的抗静电性能,添加15%的MB-CNTs即可达到理想的抗静电效果.混炼过程中,扭矩呈现先增大后减小的趋势.CNTs对TPV具有一定的补强效应.当MB-CNTs质量分数大于15%时,扭矩和拉伸强度...     

Effect of structure development on the rheological properties of PVDF/HNBR-based thermoplastic elastomer and its vulcanizates

The present work demonstrates the structure-rheology relationship of novel polyvinylidene fluoride/hydrogenated nitrile rubber blends with special reference to the effect of mixing time, which has not been amply discussed in the literature. In between 50 and 70 wt% rubber content, a yield in complex viscosity and secondary plateau in storage modulus were discerned due to interconnected droplets-matrix morphology manifesting the thermoplastic elastomeric nature of the blends (TPEs). Such network-like structure altered the rheological properties like relaxation time, capillary viscosity, die swell, elastic responses of the TPE with respect to the trend as expected according to the rule of mixing. Interestingly, in the early stages of mixing, when the dispersed size was bigger, the effect of physical network on the rheological properties was suppressed. During dynamic vulcanization (TPV), both lower and higher frequency responses in oscillatory shear flow, steady shear rheological properties, recoverable strain etc. have changed notably with mixing time. For example, although the complex viscosity of the TPV was higher at a lower frequency as compared to its TPE, it was significantly lower at a higher frequency at the beginning of dynamic curing; however, viscosity increased appreciably with time. Temperature-dependendent rheological properties were also influenced with mixing time of the compositions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48758.     

Generation of electricity using InGaAsSb and GaSb TPV cells in combustion-driven radiant sources

Electric power generation using InGaAsSb and GaSb thermophotovoltaic (TPV) cells was investigated in a gas-fired heating furnace. Electric output characteristics of the TPV cells in the combustion-driven radiant sources are presented. For the InGaAsSb cells, open circuit voltage was higher than 300 mV at a short circuit current density above 1 A/cm². The short circuit current of the InGaAsSb cells increased more rapidly than that of the GaSb cells in radiator temperature range 930–1215 °C. A mathematical model for the TPV devices was developed to describe the effect of cell bandgap and radiator temperature on electric power output and cell efficiency. Also, the design aspects of the combustion-driven TPV systems are discussed.     

Performance assessment of a biogas fuelled molten carbonate fuel cell-thermophotovoltaic cell-thermally regenerative electrochemical cycle-absorption refrigerator-alkaline electrolyzer for multigenerational applications

In recent years, there has been increasing interest in fuel cell hybrid systems. In this paper, a novel multi-generation combined energy system is proposed. The system consists of a molten carbonate fuel cell (MCFC), a thermally regenerative electro-chemical cycle (TREC), a thermo photovoltaic cell (TPV), an alkaline electrolyzer (AE) and an absorption refrigerator (AR). It has four useful outputs, namely electricity, hydrogen, cooling and heating. The overall system is thermodynamically modeled in a detailed manner while its simulation and modeling are done through the TRNSYS software tool. Power output, cooling-heating and produced hydrogen rates are determined using energetic and exergetic analysis methods. Results are obtained numerically and plotted. The maximum power output from the system is 16.14 kW while maximum energy efficiency and exergy efficiency are 86.8% and 80.4%,. The largest exergy destruction is due to the MCFC.     

动态硫化热塑性硫化胶研究进展

热塑性硫化胶(TPV)是一种在常温下具有橡胶高弹性、高温下能塑化成型的新型材料,性能优异且发展迅速。本文综述了TPV的加工设备、制备工艺、硫化体系、微观相结构(包括"海-岛"结构、"核-壳"结构和"双连续相"结构)、改性方法以及功能型TPV的研究,并对TPV的发展前景作出展望。     

Fabrication and characterization of GaSb based thermophotovoltaic cells using Zn diffusion from a doped spin-on glass source

The GaInSb material system is attractive for application in therm ophotovoltaic (TPV) cells since its band gap can be tuned to match the radiation of the emitter. At present, most of the TPV cells are fabricated using epitaxial layers and hence are expensive. To reduce the cost, Zn diffusion using elemental vapors in a semiclosed diffusion system is being pursued by several laboratories. In this paper, we present studies carried out on Zn diffusion into n-type (Te-doped) GaSb substrates in an open tube diffusion furnace. The dopant precursor was a 2000 ? thick, zinc doped spin-on glass. The diffusion was carried out at temperatures ranging from 550 to 600°C, for times from 1 to 10 h. The diffused layers were characterized by Hall measurements using step-and-repeat etching by anodic oxidation, secondary ion mass spectrometry measurements, and TPV device fabrication. For diffusion carried out at 600°C, the junction depth was 0.3 μm, and the hole concentration near the surface was 5 × 10¹⁹/cm³. The external quantum efficiency, measured without any anti-reflection coating of the TPV cells fabricated using mesa-etching had a maximum value of 38%. Masked diffusion was also carried out by opening windows in a Si₃N₄ coated, GaSb wafer. TPV cells fabricated on these structures had similar quantum efficiency, but lower dark current.     

Spectral emittance measurements of micro/nanostructures in energy conversion: a review

Micro/nanostructures play a key role in tuning the radiative properties of materials and have been applied to high-temperature energy conversion systems for improved performance. Among the various radiative properties, spectral emittance is of integral importance for the design and analysis of materials that function as radiative absorbers or emitters. This paper presents an overview of the spectral emittance measurement techniques using both the direct and indirect methods. Besides, several micro/nanostructures are also introduced, and a special emphasis is placed on the emissometers developed for characterizing engineered micro/nanostructures in high-temperature applications (e.g., solar energy conversion and thermophotovoltaic devices). In addition, both experimental facilities and measured results for different materials are summarized. Furthermore, future prospects in developing instrumentation and micro/nanostructured surfaces for practical applications are also outlined. This paper provides a comprehensive source of information for the application of micro/nanostructures in high-temperature energy conversion engineering.