scholarly journals CFD Parametric Studies for Global Performance Improvement of Open Refrigerated Display Cabinets

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Pedro Dinis Gaspar ◽  
L. C. Carrilho Gonçalves ◽  
R. A. Pitarma
Keyword(s):  
Low Cost ◽  
Thermal Response ◽  
Electrical Energy ◽  
Cfd Modelling ◽  
Refrigeration Equipment ◽  
Numerical Predictions ◽  
Global Performance ◽  
Back Panel ◽  
Parametric Studies ◽  
Optimized Model

A detailed CFD modelling of an open refrigerated display cabinet has been formulated in a previous study. Some modifications are introduced in order to perform parametric studies dealing with low-cost geometrical and functional characteristics for improvement of the global performance and energy efficiency. The parametric studies are devoted to the analysis of the thermal response and behaviour inside the food conservation space influenced by (1) air flow rate through the evaporator heat exchanger; (2) air curtain behaviour; (3) hole dimensions and distribution of the back panel; (4) discharge and return grilles angles; and (5) flow deflectors inside the internal duct. The analysis of the numerical predictions from the parametric studies allows the development of an optimized model for the conception of an open refrigerated display cabinet with a more adequate configuration. The numerical predictions of the optimized model show lower product temperature and reduced electrical energy consumption, allowing the improvement of the food safety and the energy rationalization of the refrigeration equipment.

scholarly journals Detailed CFD Modelling of Open Refrigerated Display Cabinets

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Pedro Dinis Gaspar ◽  
L. C. Carrilho Gonçalves ◽  
R. A. Pitarma
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Thermal Response ◽  
Experimental Tests ◽  
Cfd Modelling ◽  
Humidity Effect ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Parametric Studies ◽  
Flow Through

A comprehensive and detailed computational fluid dynamics (CFDs) modelling of air flow and heat transfer in an open refrigerated display cabinet (ORDC) is performed in this study. The physical-mathematical model considers the flow through the internal ducts, across fans and evaporator, and includes the thermal response of food products. The air humidity effect and thermal radiation heat transfer between surfaces are taken into account. Experimental tests were performed to characterize the phenomena near physical extremities and to validate the numerical predictions of air temperature, relative humidity, and velocity. Numerical and experimental results comparison reveals the predictive capabilities of the computational model for the optimized conception and development of this type of equipments. Numerical predictions are used to propose geometrical and functional parametric studies that improve thermal performance of the ORDC and consequently food safety.

VIBRATION-BASED ENERGY HARVESTER FOR SUSTAINABLE STRUCTURAL HEALTH MONITORING SYSTEM: A CASE STUDY ON A PRESTRESSED CONCRETE GIRDER

2020 ◽  
Vol 1 (1) ◽  
pp. 16-19
Author(s):  
Tuan Minh Ha ◽  
Saiji Fukada ◽  
Toshiyuki Ueno ◽  
Duc-Duy Ho
Keyword(s):  
Prestressed Concrete ◽  
Energy Harvester ◽  
Low Cost ◽  
High Sensitivity ◽  
Electrical Energy ◽  
Open Circuit ◽  
High Durability ◽  
Parametric Studies ◽  
Self Powered ◽  
Concrete Girder

Energy harvesting technology generating electrical energy from structural responses has been in the spotlight recently because of the development of self-powered autonomous wireless sensor systems. This study proposed and tested a high-sensitivity, high-durability, low-cost vibration power-generating device using a magnetostrictive element (Fe-Ga alloy) on a real-scale prestressed concrete girder to investigate its practical performance. The device comprises a unimorph layer having a magnetostrictive element attached to a U-shaped frame with a permanent magnet for magnetic bias wound about by a coil. An evaluation of a prototype device using a Fe-Ga element of 4 × 0.5 × 16 mm was performed. With a weight of 1221 g attached, an open-circuit voltage of ~1 V at an oscillation of 9.058 Hz and 3.8 m/s2 was generated by free damped vibrations applied via a person jumping vertically from a chair to the girder. In addition, parametric studies were carried out by changing impact locations, weights, and device locations in order to examine their possible effects on the performance of the proposed energy harvester.

The Effectiveness of the Unit Cell Method in Numerically Modeling and Designing Liquid Cooled Heatsinks

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Ali C. Kheirabadi ◽  
Dominic Groulx
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Parametric Design ◽  
Unit Cell ◽  
Liquid Cooling ◽  
Cell Method ◽  
Numerical Predictions ◽  
Finite Element Package ◽  
Parametric Studies ◽  
Relative Differences

This study compares two numerical strategies for modeling flow and heat transfer through mini- and microchannel heatsinks, the unit cell approximation, and the full 3D model, with the objective of validating the former approach. Conjugate heat transfer and laminar flow through a 2 × 2 cm2 copper–water heatsink are modeled using the finite element package COMSOL Multiphysics 5.0. Parametric studies showed that as the heatsink channels’ widths were reduced, and the total number of channels increased, temperature and pressure predictions from both models converged to similar values. Relative differences as low as 5.4% and 1.6% were attained at a channel width of 0.25 mm for maximum wall temperature and channel pressure drop, respectively. Due to its computational efficiency and tendency to conservatively overpredict temperatures relative to the full 3D method, the unit cell approximation is recommended for parametric design of heatsinks with channels’ widths smaller than 0.5 mm, although this condition only holds for the given heatsink design. The unit cell method is then used to design an optimal heatsink for server liquid cooling applications. The heatsink has been fabricated and tested experimentally, and its thermal performance is compared with numerical predictions. The unit cell method underestimated the maximum wall temperature relative to experimental results by 3.0–14.5% as the flowrate rose from 0.3 to 1.5 gal/min (1.1–5.7 l/min).

Carbonyl-Iron Electrodes for Rechargeable-Iron Batteries

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
A. Sundar Rajan ◽  
M. K. Ravikumar ◽  
K. R. Priolkar ◽  
S. Sampath ◽  
A. K. Shukla
Keyword(s):  
Carbonyl Iron ◽  
Large Scale ◽  
Low Cost ◽  
Specific Capacity ◽  
Electrical Energy ◽  
Slow Increase ◽  
Faradaic Efficiency ◽  
Nickel Iron ◽  
In Situ Xrd ◽  
Iron Electrodes

AbstractNickel-iron and iron-air batteries are attractive for large-scale-electrical-energy storage because iron is abundant, low-cost and non-toxic. However, these batteries suffer from poor charge acceptance due to hydrogen evolution during charging. In this study, we have demonstrated iron electrodes prepared from carbonyl iron powder (CIP) that are capable of delivering a specific discharge capacity of about 400 mAh g−1 at a current density of 100 mA g−1 with a faradaic efficiency of about 80%. The specific capacity of the electrodes increases gradually during formation cycles and reaches a maximum in the 180th cycle. The slow increase in the specific capacity is attributed to the low surface area and limited porosity of the pristine CIP. Evolution of charge potential profiles is investigated to understand the extent of charge acceptance during formation cycles. In situ XRD pattern for the electrodes subsequent to 300 charge/discharge cycles confirms the presence of Fe with Fe(OH)2 as dominant phase.

LaF3-BaF2-KF derived electrolyte in solid state fluoride-ion battery

2010 ◽  
Vol 1266 ◽  
Author(s):  
Dechao Wang ◽  
Anji Reddy Munnangi ◽  
Horst Hahn ◽  
Max Fichtner
Keyword(s):  
Solid State ◽  
High Performance ◽  
Low Cost ◽  
Electrical Energy ◽  
Composite Cathode ◽  
Fluoride Anion ◽  
Cubic Symmetry ◽  
Group A ◽  
Battery Technology ◽  
Preparation Techniques

AbstractSolid-state based battery technology offers, in principle, the largest temperature range (from room temperature to 500 °C) of any battery technology. In fluoride based batteries, the chemical reaction used to create electrical energy is a solid-state reaction of a metal with fluoride anion [1]. Among the various types of solid preparation techniques, the mechanochemical synthesis has been recognized as a powerful route to novel, high-performance, and low-cost materials [2]. Thus, a mixed and highly disordered fluoride phase with retained cubic symmetry can be obtained with a very high Fˉ diffusivity [3].In our group, a series of new electrolytes was developed, namely LaF3-BaF2-KF solid solutions, using mechanosynthesis method. The cubic structure of the product was confirmed by XRD. The nanoscale nature and morphology of the samples were characterized by SEM and TEM. First Solid-state electrochemical cells were built with LiF based composite cathode, LaF3-BaF2-KF derived electrolyte and Fe based composite anode.

scholarly journals Hydraulic Mixing Modelling in Reactor for Biogas Production

2012 ◽  
Vol 33 (4) ◽  
pp. 621-628 ◽  
Author(s):  
Andrzej G. Chmielewski ◽  
Aleksandra Berbeć ◽  
Michał Zalewski ◽  
Andrzej Dobrowolski
Keyword(s):  
Biogas Production ◽  
Low Cost ◽  
Production Plant ◽  
Mixing Conditions ◽  
Cfd Modelling ◽  
Two Stage ◽  
Industrial Installation

Two-stage biogas production plant consists of two reactors: a hydrolyser and a fermentor. The bioreactor construction has to meet three requirements: low cost and simplicity of construction and good biomass mixing conditions with an application of appropriate method. This paper reports CFD modelling of hydraulic mixing in the tank to be applied in a two-stage industrial installation.

Low-Cost and Real-Time Measurement System for Electrical Energy Measuring of a Smart Microgrid

2021 ◽  
pp. 3-16
Author(s):  
Oscar Izquierdo-Monge ◽  
Paula Peña-Carro ◽  
Mariano Martín Martínez ◽  
Luis Hernández-Callejo ◽  
Oscar Duque-Perez ◽  
...  
Keyword(s):  
Real Time ◽  
Measurement System ◽  
Low Cost ◽  
Electrical Energy ◽  
Time Measurement ◽  
Real Time Measurement

Flexible, low-cost and scalable, nanostructured conductive paper-based, efficient hygroelectric generator

2021 ◽  
Author(s):  
Kelly S. Moreira ◽  
Diana Lermen ◽  
Leandra P. dos Santos ◽  
Fernando Galembeck ◽  
Thiago A. L. Burgo
Keyword(s):  
Real World ◽  
Energy Efficient ◽  
Low Cost ◽  
Electrical Energy ◽  
Conductive Paper ◽  
Real World Applications

Converting humidity into useful electrical energy was only recently demonstrated and the improvements presented in this work are not only highly energy efficient, but also contributes to the development of scalable, real-world applications.

Technical and Economic Evaluation of Hybrid wind/PV/Battery Systems for Off-Grid Areas using HOMER Software

2016 ◽  
Vol 7 (1) ◽  
pp. 134 ◽  
Author(s):  
Alireza Gheiratmand ◽  
Reza Effatnejad ◽  
Mahdi Hedayati
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Low Cost ◽  
Electrical Energy ◽  
Petroleum Products ◽  
Medical Emergency ◽  
Technological Advances ◽  
Economical Consideration

Incremental consumption of electrical energy, reduction of fossil fuel resources and environmental pollution problems caused by them are the main reasons, which tend the managers and officials in countries energy sector to develop use of renewable systems. In the not-too-distant future the use of renewable energy such as wind and solar will be very important and will play predominant role in economic indices of power systems. In recent years, technological advances in renewable energy and increasing price of petroleum products promote system managers to use low-cost and low-emission energy resources in form of hybrid systems and widespread propagation of electricity generation have been developed in remote areas. In Hybrid systems two or more sources of renewable energy is typically adopted, which increases the reliability of these systems. In this paper, the technical and economical consideration of a wind and solar hybrid system to supply electrical energy for a number of remote users (aid and medical emergency Shelter in Yazd) is provided. In order to investigate optimization and economic analysis of the proposed hybrid system, the HOMER software is used.  The results of Simulation in HOMER software show that Solar cells and wind systems with average generation power of 896 kWh/yr. and 343 kWh/yr., consist proportion of 72 and 28 percent of the total generated energy respectively, which are dedicated to satisfy the loads

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