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Kuwait City, Kuwait

Alajmi A.,College of Technological Studies
Energy and Buildings

The building considered in this case study is a 2-story educational facility with a total floor area of 7020 square meter located in a harsh hot summer climate (State of Kuwait) and served by 4 air-cooled reciprocating chillers. Energy audit techniques were carried out by an energy audit team (EAT) to identify any energy conservation opportunities (ECOs). Level 1 (walk-through assessment) and level 2 (survey and data analysis) audits were conducted over all building zones. These levels of assessments proved that the building and its mechanical and electrical systems were improperly maintained and inefficiently operated. The building assessment produced a list of ECOs classified as non-retrofitting (no or minimal cost) and retrofitting (with cost) recommendations. Interestingly, the non-retrofitting ECOs saved 6.5% of the building's annual energy consumption, while the retrofitting ECOs can save up to 49.3%; this results in a 52% total saving. The savings were calculated using a building simulation software (DesignBuilder). Finally, a cost analysis of the findings was performed; the result showed a pay-back period of less than 6 months for both non-retrofitting and the most effective retrofitting actions. © 2012 Elsevier B.V. All rights reserved. Source

Al-ajmi F.F.,College of Technological Studies
Building and Environment

In Kuwait, as in most countries with a typical dry desert climate, the summer season is long with a mean daily maximum temperature of 45 °C. Centralized air-conditioning, which is generally deployed from the beginning of April to the end of October, can have tremendous impact on the amount of electrical energy utilized to mechanically control the internal environment in mosque buildings. The indoor air temperature settings for all types of air-conditioned buildings and mosque buildings in particular, are often calculated based on the analytical model of ASHRAE 55-2004 and ISO 7730. However, a field study was conducted in six air-conditioned mosque buildings during the summers of 2007 to investigate indoor climate and prayers thermal comfort in state of Kuwait. The paper presents statistical data about the indoor environmental conditions in Kuwait mosque buildings, together with an analysis of prayer thermal comfort sensations for a total of 140 subjects providing 140 sets of physical measurements and subjective questionnaires were used to collect data. Results show that the neutral temperature (T n) of the prayers is found to be 26.1 °C, while that for PMV is 23.3 °C. Discrepancy of these values is in fact about 2.8 °C higher than those predicted by PMV model. Therefore, thermal comfort temperature in Kuwait cannot directly correlate with ISO 7730 and ASHRAE 55-2004 standards. Findings from this study should be considered when designing air conditioning for mosque buildings. This knowledge can contribute towards the development of future energy-related design codes for Kuwait. © 2010 Elsevier Ltd. Source

El-Daou M.K.,College of Technological Studies
Computers and Mathematics with Applications

We develop a method to solve a class of second-order ordinary differential equations with highly oscillatory solutions. The method consists in combining three different techniques: LegendreGauss spectral Tau method, exponential fitting, and coefficient perturbation methods. With our approach, the resulting approximate solutions are expressed in terms of an exponentially weighted Legendre polynomial basis en<0, where ωn are appropriately chosen complex numbers. The accuracy and efficiency of the method are discussed and illustrated numerically. © 2011 Elsevier Ltd. All rights reserved. Source

Mahmoud M.A.,College of Technological Studies
Critical Reviews in Solid State and Materials Sciences

This article provides a review of methods of predicting mass-induced resonance shifts in microcantilevers. It combines a review of factors that influence resonance frequency shifts, such as material properties, size effects, and support compliance with a comparative study of accuracy of predicting resonance shifts due to mass adsorption. The applicability and accuracy of widely used formulas to correlate mass addition with resonance shift are assessed through comprehensive comparison with experimental measurements and numerical methods. The methods include both distributed parameter and lumped parameter formulations. The applications include distributed added masses, tip masses, and added mass at arbitrary locations along a cantilever span. © 2016 Taylor & Francis Group, LLC. Source

Fardoun A.A.,United Arab Emirates University | Ismail E.H.,College of Technological Studies
IEEE Transactions on Industry Applications

In this paper, a new single-switch nonisolated dcdc converter with high voltage transfer gain and reduced semiconductor voltage stress is proposed. The proposed topology utilizes a hybrid switched-capacitor technique for providing a high voltage gain without an extreme switch duty cycle and yet enabling the use of a lower voltage and RDS-ON MOSFET switch so as to reduce cost, switch conduction, and turn-on losses. In addition, the low voltage stress across the diodes allows the use of Schottky rectifiers for alleviating the reverse-recovery current problem, leading to a further reduction in the switching, and conduction losses. The principle of operation and a comparison with other high step-up topologies are presented. Two extensions of the proposed converter are also introduced and discussed. Simulation and experimental results are also presented to demonstrate the effectiveness of the proposed scheme. © 2010 IEEE. Source

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