scholarly journals Experimental Investigation of Energy Consumption of A Commercial Walkin Freezer

Author(s):  
Mohamed Metwalli ◽  
Minhajul Haque Minar ◽  
Mostafa H. Sharqawy
Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4610 ◽  
Author(s):  
Shoaib Sarfraz ◽  
Essam Shehab ◽  
Konstantinos Salonitis ◽  
Wojciech Suder

Laser drilling is a high-speed process that is used to produce high aspect ratio holes of various sizes for critical applications, such as cooling holes in aero-engine and gas turbine components. Hole quality is always a major concern during the laser drilling process. Apart from hole quality, cost and productivity are also the key considerations for high-value manufacturing industries. Taking into account the significance of improving material removal quantity, energy efficiency, and product quality, this study is performed in the form of an experimental investigation and multi-objective optimisation for three different laser drilling processes (single-pulse, percussion, and trepanning). A Quasi-CW fibre laser was used to produce holes in a 1 mm thick IN 718 superalloy. The impacts of significant process parameters on the material removal rate (MRR), specific energy consumption (SEC), and hole taper have been discussed based on the results collected through an experimental matrix that was designed using the Taguchi method. The novelty of this work focuses on evaluating and comparing the performance of laser drilling methods in relation to MRR, SEC, and hole quality altogether. Comparative analysis revealed single-pulse drilling as the best option for MRR and SEC as the MRR value reduces with percussion and trepanning by 99.70% and 99.87% respectively; similarly, percussion resulted in 14.20% higher SEC value while trepanning yielded a six-folds increase in SEC as compared to single-pulse drilling. Trepanning, on the other hand, outperformed the rest of the drilling processes with 71.96% better hole quality. Moreover, optimum values of parameters simultaneously minimising SEC and hole taper and maximising MRR are determined using multi-objective optimisation.


Volume 3 ◽  
2004 ◽  
Author(s):  
Ankur Jain ◽  
Rochan Raj Upadhyay ◽  
Samarth Chandra ◽  
Manish Saini ◽  
Sunil Kale

A ceiling fan is the predominating comfort provider in tropical regions worldwide. It consists of an assembly of an electric motor with 3–4 blades suspended from the ceiling of a room. Despite its simplicity and widespread use, the flow induced by a ceiling fan in a closed room has not been investigated, and sub-optimal designs are in wide use. There is vast potential for energy conservation and improved comfort by developing optimized fan designs. This work develops a fundamental understanding of the flow characteristics of a ceiling operating inside a closed room. Using smoke from thick incense sticks, the flow field created by the ceiling fan is visualized. In most regions, the flow is periodic and three-dimensional. Vortices are seen to be attached to the blade tip and hub, which reduces downward flow and increases energy consumption. Only the middle 75% of blade actually pushes the air downwards, and the comfort region is limited to a cylinder directly under the blades; velocities in this region were measured with a vane anemometer. Winglets and spikes attached to the blade tip disrupted the tip vortex, and increased downflow by about 13% without any increase in power consumption.


Measurement ◽  
2016 ◽  
Vol 92 ◽  
pp. 391-399 ◽  
Author(s):  
Fatemeh Ghadiri Modarres ◽  
Mehdi Rasti ◽  
Mahmood Mastani Joybari ◽  
Mohammad Reza Fatemi Nasrabadi ◽  
Omid Nematollahi

2018 ◽  
Vol 9 (2) ◽  
pp. 364 ◽  
Author(s):  
edy Susanto ◽  
Muhammad Idrus ◽  
Nasruddin Nasruddin ◽  
Budihardjo Budihardjo

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