Simulation Study for the Series Connected Bundles of Microtubular SOFCs

Author(s):  
Yoshihiro Funahashi ◽  
Toru Shimamori ◽  
Toshio Suzuki ◽  
Yoshinobu Fujishiro ◽  
Masanobu Awano ◽  
...  

Solid oxide fuel cells (SOFCs) have the highest energy conversion efficiency among various power generators and expected to be earlier commercialization. Our study aims to develop fabrication techniques of microtubular SOFC bundles and establish realistic bundle structure for kilowatt class module. So far, we have succeeded to establish fabrication technology of the microtubular SOFC bundles using porous supporting matrices. In this study, the simulation study of the microtubular SOFC bundle was carried out to understand Joule heat and temperature distribution in the microtubular SOFC bundle during operation. The results indicated that the method of current collection had to be carefully considered, since the total output power loss of the bundle was estimated to be 27.8%. The temperature distribution of the bundle using porous MgO matrices turned out to be moderate compared with that in the previous bundle using porous (La,Sr)(Co,Fe)O3 matrices due to the difference in the thermal conductivity of each matrix constitute.

Author(s):  
Yoshihiro Funahashi ◽  
Toru Shimamori ◽  
Toshio Suzuki ◽  
Yoshinobu Fujishiro ◽  
Masanobu Awano

Microtubular solid oxide fuel cells (SOFCs) are shown to be robust under rapid temperature changes and have large electrode area per volume (high volumetric power density). Such features are believed to increase a variety of application. Our study aims to establish a fabrication technique for microtubular SOFC bundles with the volumetric power density of 2 W cm−3 at 0.7 V. So far, we have succeeded to develop a fabrication technology for microtubular SOFC bundles using anode supported tubular SOFCs and cathode matrices with well-controlled microstructures. A key to improve the performance of the microtubular SOFC bundles is to optimize the microstructure of the cathode matrices because it influences a pressure loss for air and electric current collection. In this paper, a simulation study of an air flow, temperature, and potential distributions in the microtubular SOFC bundle was conducted in order to understand the characteristics of the present bundle design. In addition, operating conditions of the microtubular SOFC bundles was discussed for realizing the target power density of 2 W cm−3.


2017 ◽  
Vol 46 (18) ◽  
pp. 5872-5879 ◽  
Author(s):  
Mandvi Saxena ◽  
Tanmoy Maiti

Increasing electrical conductivity in oxides, which are inherently insulators, can be a potential route in developing oxide-based thermoelectric power generators with higher energy conversion efficiency.


2016 ◽  
Vol 8 (3) ◽  
pp. 1471-1474
Author(s):  
Vinayak S. Suragonda ◽  
B. S. Reddy ◽  
O. P. Sharma

The current study aimed at evaluating technical efficiency and change in output of pulse crops in Karnataka. Totally 180 farmers were selected for eliciting required information on adoption of A3P technology. The results of the study revealed that majority of the farmers were operating above 80 per cent efficiency levels in both pulses across the farmers of A3P and Non-A3P. Further, more than 53 per cent of farmers' under redgram and 56 per cent under bengalgram have achieved 100 per cent efficiency level in A3P farmers category. Decomposition of the difference in total output between A3P and Non-A3P farmers was 13.23 and 14.86 per cent in redgram and bengalgram crops respectively. The A3P technology has alone contributed to the extent of 29 and 22 per cent to the total change in redgram and bengalgram output indicating output can be increased by about 29 and 22 per cent if the farmers could switch over from traditional practices (Non-A3P) to A3P technology. There is need to educate farmers on optimum use of inputs through conducting intensive trainings on A3P technology by KVK’s and other extension agencies to increase the supply of pulses in the country.


2021 ◽  
pp. 1-23
Author(s):  
Dandan Pang ◽  
Aibing Zhang ◽  
Zhenfei Wen ◽  
Baolin Wang ◽  
Ji Wang

Abstract Thermoelectric power generators (TEGs) have been attracted increasing attention recently due to their capability of converting waste heat into useful electric energy without hazardous emissions. This paper develops a theoretical model to analyze the thermoelectric performance of TEGs with cylindrical legs. The influence of heat convection loss between lateral surfaces of thermoelectric legs and ambient environment on the energy conversion efficiency is investigated. For the idealized model, closed-form solutions of optimal electric current, maximum power output and maximum energy conversion efficiency are obtained, a new dimensionless impact factor H is introduced to capture the heat convection effect. The impact factor H depends on the ratio of heat conductivity to heat convection coefficient and geometry size of thermoelectric legs, as well as the temperature ratio of heat sink to hot source. The performance can be evaluated by the figure of merit, impact factor H and temperature gradient across the hot source and heat sink for a well-designed TEG with cylindrical legs. For the case of considering contact resistance, it is found that there exists an optimal leg's height for maximum energy conversion efficiency due to the heat convection on lateral surfaces of thermoelectric leg. The proposed theoretical model in this paper will be very helpful in the designing of actual TEG devices.


2021 ◽  
Vol 103 (1) ◽  
pp. 83-92
Author(s):  
Hai Feng ◽  
Dhruba Panthi ◽  
Yanhai Du

2020 ◽  
Author(s):  
Tao Hong ◽  
Hao Chen ◽  
Li Liu ◽  
Weiqi Liu ◽  
Longxue Li ◽  
...  

Abstract Background Coix seed is a traditional Chinese medicine with pharmacological effects and food efficacy. It is well-know and widely used in China and other Asian countries. Fayiren is a new artillery material processed from Coix Seed. This is the first study of the diuretic activities of Fayiren and coix seed in normal rats. Methods Forty-eight rats were randomly divided into 6 groups (8 rats/group) according to body mass and urine volume stratification, namely model (physiological saline) group, positive control (furosemide 20 mg/kg) group, coix seed (1666 mg/kg) group, low-dose of Fayiren group (166 mg/kg) and high-dose Fayiren group (1666 mg/kg). Rats were fasted for 16 h before the experiment, with normal water supply. Immediately after administration, each group of rat was placed in a metabolic cage, and urine was collected once after every hour for a total of 6 times. The urine volume at each time point for collection was measured, and then totaled. After the 6 h recording procedure, the treatments were administered once a day and the urine was collected at the 24th, 48th, 72th, 96th, 110th, 134th, and 158th hours from the start respectively. The urine pH and Na +, K +, Ca 2+, Cl - concentrations at each time point of each group of rats were measured. The contents of ALD, ANP, ADH, Na+-K+-ATPase, the gene expression and protein levels of AQP1, AQP2 and AQP3 in urine of rats in each group were determined. SPSS22.0 statistical software was used to analyze the experimental data. One way ANOVA and multiple comparisons between LSD groups were performed. The difference is considered significant When p < 0.05 or p < 0.01. Results After the administration of Fayiren and coix seed, compared with normal rats, the total output of urine in the high-dose coix seed & Fayiren group and the positive control group both increased; In addition, the contents of Na+ and Cl-in urine in these groups increased as well. However, the content of K+ did not increase in all groups. Contents of ALD and ADH was decreased and increased contents of ANP observed in urine in both high-dose and low-dose Fayiren groups with significant differences from model group (P < 0.05). Coix seed significantly reduced ADH and increased ANP levels compared with model group (P < 0.05). There was no obvious change in the urine pH content in urine of all rats. All the aquaporin (AQP1, AQP2, and AQP3) contents were decreased comparing to the model group, the coix seed group, as well as the Fayiren group. The effect of coix seed was particularly notable on AQP2, and the difference was significant against the Furosemide group (P < 0.05). By contrast, Fayiren showed greater effects on AQP1 and AQP3, with statistically significant difference comparing to the model group (P༜0.05). Conclusions This study will provide experimental evidence for explaining the different mechanisms of diuretic effects in natural medicine use of coix seed and artillery material processed from Coix Seed. The Fayiren may affect the reabsorption of water in the kidney through mechanisms related to increased ANP secretion,decreased ALD and ADH secretion in urine, and it significantly affect the expression of aquaporin 1 and aquaporin 3. However, coix seed may increase ANP but decreased ADH secretion, further affecting the expression of aquaporin2 and exert diuretic effect.


2020 ◽  
Vol 902 ◽  
pp. 97-102
Author(s):  
Tran Trong Quyet ◽  
Pham Tuan Nghia ◽  
Nguyen Thanh Toan ◽  
Tran Duc Trong ◽  
Luong Hong Sam ◽  
...  

This paper presents a prediction of cutting temperature in turning process, using a continuous cutting model of Johnson-Cook (J-C). An method to predict the temperature distribution in orthogonal cutting is based on the constituent model of various material and the mechanics of their cutting process. In this method, the average temperature at the primary shear zone (PSZ) and the secondary shear zone (SSZ) were determined for various materials, based on a constitutive model and a chip-formation model using measurements of cutting force and chip thicknes. The J-C model constants were taken from Hopkinson pressure bar tests. Cutting conditions, cutting forces and chip thickness were used to predict shear stress. Experimental cutting heat results with the same cutting parameters using the minimum lubrication method (MQL) were recorded through the Testo-871 thermal camera. The thermal distribution results between the two methods has a difference in value, as well as distribution. From the difference, we have analyzed some of the causes, finding the effect of the minimum quantity lubrication parameters on the difference.


Author(s):  
Toshio Suzuki ◽  
Toshiaki Yamaguchi ◽  
Yoshinobu Fujishiro ◽  
Masanobu Awano ◽  
Yoshihiro Funahashi

Ceramic reactors, which convert materials and energy electrochemically, are expected to solve various environmental problems, and use of micro reactor design was shown to realize high performance reactor with high thermal durability operable at lower temperatures. Our research project “Advanced Ceramic Reactor” supported by NEDO targets to develop new fabrication technology for such micro reactors and modules using conventional, commercially available materials. In this study, fabrication technology of micro tubular ceramic reactors have been investigated for aiming solid oxide fuel cells (SOFCs) application, such as small distributed power generators, APU for vehicles, and portable power sources. So far, micro tubular SOFCs under 1 mm diam. using doped ceria electrolyte and Ni-ceria based cermet for tubular support has been successfully developed and evaluated. The single micro tubular SOFC showed cell performance of 0.46 W/cm2 (@0.7 V) at 550 °C with H2 fuel. Bundle design for such tubular cell was also proposed and fabricated. Discussion will cover fabrication technology of single tubular SOFC and bundle, and optimization of the cell and bundle design by considering gas pressure loss and current collecting loss.


2020 ◽  
Vol Volume 13 ◽  
pp. 205-211
Author(s):  
Yoshikazu Yamaguchi ◽  
Tetsuya Miyashita ◽  
Yuko Matsuda ◽  
Makoto Sasaki ◽  
Shunsuke Takaki ◽  
...  

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