115,305 research outputs found
Design improvement of circular molten carbonate fuel cell stack through CFD Analysis
No full textMolten carbonate fuel cell (MCFC) is a promising technology for distributed power generation. The core of an MCFC power generation unit is the stack, where various fuel cells are connected together in series and parallel in order to obtain the desired voltage and power. Stack geometry and configuration are major engineering topics, as inhomogeneous temperature or mass fractions cause inefficient performances of the fuel cells, as efficiency and power smaller than the expected and shorter lifetime. A detailed model is a useful tool to improve stack performances, through design improvements. In this paper, a 3D model of a stack composed of 15 circular MCFC, considering heat, mass and current transfer as well as chemical and electrochemical reactions is presented. The model validation is conducted using some preliminary experimental data obtained for an MCFC stack developed in the Fabbricazioni Nucleari laboratories. These results are examined in order to improve the stack configuration. It is shown that power density may be increased of about 20% through double side feeding. In addition, the average temperature gradients in the axial direction are reduced of more than 70%. Significant reductions in the temperature gradients, especially in transversal direction, can be achieved by adjusting the mass flow rate of cathodic gas supplied to the various cell
Numerical computation for parallel plate thermoacoustic heat exchangers in standing wave oscillatory flow
No full textA simplified computational method for studying the heat transfer characteristics of parallel plate thermoacoustic heat exchangers is presented. The model integrates the thermoacoustic equations of the standard linear theory into an energy balance-based numerical calculus scheme. Details of the time-averaged temperature and heat flux density distributions within a representative domain of the heat exchangers
and adjoining stack are given. The effect of operation conditions and geometrical parameters on the heat exchanger performance is investigated and main conclusions relevant for HX design are drawn as far as fin length, fin spacing, blockage ratio, gas and secondary fluid-side heat transfer coefficients are concerned. Most relevant is that
the fin length and spacing affect in conjunction the heat exchanger behaviour and have to be simultaneously optimized to minimize thermal losses localized at the HX-stack
junctions. Model predictions fit experimental data found in literature within 36% and 49% respectively at moderate and high acoustic Reynolds numbers
DESIGN & DEVELOPMENT OF PLANAR SOLID OXIDE FUEL CELL STACK
No full textIn the present work, planar anode-supported Solid Oxide Fuel Cell short-stacks have been designed, assembled, tested and characterized. The design of the stacks and its components (frame, housing, interconnect, compressive and bonded seals) required a great attention to the materials properties (i.e. thermal expansion coefficient compatibility, durability, strength and oxidation resistance, conductivity and so on), as well as to the fluid-dynamic analysis focused on flow field and gas distribution. Then, a careful analysis was done based on a multidisciplinary approach to select the stack components materials, geometries, and dimensions; in order to assure a high performing stack at elevated temperatures with cost reduction of materials, parts manufacturing and assembly procedure. The materials selected were: Crofer®22APU for the interconnect and the frame; AISI 316L for bolts and housing; Thermiculite® 866 for the compressive seal placed between the frame and the interconnect plate; Flexible Mica Paper for the compressive seal positioned between the interconnect endplate and the housing; SiO2-CaO-Al2O3-Na2O glass-ceramic sealant for the bonded seal to join the frame with the cell. On the other hand, the stack assembly was focused on the implementation of innovative and simple procedures, which allowed power capacity scale-up in accordance to power requirements. In this work, two different stack configurations were produced: with one cell (for initial testing of the materials and fluid-dynamic selected solutions) and with three cells. It must be mentioned that all developed stacks in this research were assembled with commercial cells "ASC3" from H.C. Starck. Also, calculations at ambient temperature and 800°C were done in the stack compression system to determine the proper tightening torque to be applied: this value was 50N. Although this calculation took into consideration the loss of tightening torque at high temperatures, some marks were found in housing and micas during the stack inspection after disassembly. These marks are a clear indicator of gas leakage. Additionally, a study was carried out related to the effect of the protective Mn1.5Co1.5O4 coating deposited on interconnect surface to prevent the cathode Cr poisoning. This experiment was executed in the stack of one cell configuration. No voltage degradation was observed during the galvanostatic experiment of 360 h at 800°
tum-gis/tum-gis-iot-stack-k8s: tum-gis-iot-stack-k8s-0.10.3-beta1
No full text<p>Helm Chart for the TUM-GI IoT stack. See <a href="https://github.com/tum-gis/tum-gis-iot-stack-k8s/blob/main/CHANGELOG.md">CKANGELOG</a> for changes.</p>
Algorithmic Debugging of Real-World Haskell Programs: Deriving Dependencies from the Cost Centre Stack
No full textExisting algorithmic debuggers for Haskell require a transformation of all modules in a program, even libraries that the user does not want to debug and which may use language features not supported by the debugger. This is a pity, because a promising ap- proach to debugging is therefore not applicable to many real-world programs. We use the cost centre stack from the Glasgow Haskell Compiler profiling environment together with runtime value observations as provided by the Haskell Object Observation Debugger (HOOD) to collect enough information for algorithmic debugging. Program annotations are in suspected modules only. With this technique algorithmic debugging is applicable to a much larger set of Haskell programs. This demonstrates that for functional languages in general a simple stack trace extension is useful to support tasks such as profiling and debugging
tum-gis/tum-gis-iot-stack-k8s: tum-gis-iot-stack-k8s-0.10.0
No full textHelm Chart for the TUM-GI IoT stack
tum-gis/tum-gis-iot-stack-k8s: tum-gis-iot-stack-k8s-0.9.8
No full textHelm Chart for the TUM-GI IoT stack
Achieving 360 NL h(-1) Hydrogen Production Rate Through 30-Cell Solid Oxide Electrolysis Stack with LSCF-GDC Composite Oxygen Electrode
No full textA 30-cell solid oxide electrolysis (SOE) stack consisting of 30-cell planar Ni-YSZ hydrogen electrode-supported single cell with La0.6Sr0.4Co0.2Fe0.8O3-delta-Ce0.9Gd0.1O1.95 (LSCF-GDC) composite oxygen electrodes, interconnects, and sealing materials was tested at 750 degrees C in steam electrolysis mode for hydrogen production. The direction of gas flow in the stack was a cross-flow configuration, and the stack configuration was designed to open gas flow channels at the air outlet. The electrolysis efficiency of the stack was higher than 100% at 90/10H(2)O/H-2 ratio under <0.5 A cm(-2) current density. During hydrogen production, the stack was operated at 750 degrees C under 0.5 A cm(-2) constant current density for more than 500 h with 4.06% k h(-1) degradation rate. Up to 73% steam conversion rate and 91.6% current efficiency were obtained; the net hydrogen production rate reached as high as 361.4 NL h(-1). Our results suggested that the SOE stack that was designed with LSCF-GDC composite oxygen electrode could be used to conduct large-scale hydrogen production
tum-gis/tum-gis-iot-stack-k8s: tum-gis-iot-stack-k8s-0.9.5
No full textHelm Chart for the TUM-GI IoT stack
tum-gis/tum-gis-iot-stack-k8s: tum-gis-iot-stack-k8s-0.9.6
No full textHelm Chart for the TUM-GI IoT stack
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