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Article
EXPERIMENTAL INVESTIGATION OF USING NEW SHAPE AUGMENTATIONS FOR ENHANCING HEAT TRANSFER IN HEAT EXCHANGERS

Author: Nassr Fadhil Hussein
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2017 Volume: 21 Issue: 6 Pages: 80-91
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The present investigation aims to study experimentally the effect of using basket twisted bars as a new shape of turbulators in order to achieve better heat transfer inside tube heat exchangers. In this study, air is used as a working fluid with six different values of flow rates (Reynolds number values vary from 6000 to 13500), while the value of heat flux is kept constant in this investigation. In addition, the effect of spacing ratio (SR( between these turbulators is taken into account. Therefore, 3, 4 and 5 pieces of these turbulators are distributed along the test section during experiments. The results show that the heat transfer rate for all cases tends to increase with rising Reynolds number value, while the friction factor shows downward behavior with the same Reynolds number value. In addition, it is found that (SR=4.2) gives maximum heat transfer rate with 115.9 % above plain tube case. Friction factor values increase by 313%, 235% and 193% for SR= 4.2, 6.4 and 11 respectively comparing with plain tube). The enhancement efficiency also increases when inserting baskets twisted bars with rates 127.5 %, 134.3 % and 139.8 % for SR= 11, 6.4 and 4.2 respectively.


Article
Energy Saving in Power Consumption by Using Double Glazing Windows in Iraq

Authors: Walaa M. Hashim --- Hisham A. Hoshi
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 9 Part (A) Engineering Pages: 1002-1007
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

It is generally accepted that the summer in Iraq is relatively hot season, where the temperature sometimes reaches 60 Cº. Accordingly, most of the Iraqi houses are characterized as having a large area of windows with a single glass, which could be resulted in a significant loss in cooling energy. Hence, the present research concern is to examine the effect of using double glass windows (as an alternative to single glass) on the saving in which energy normally used in houses and buildings at July and August for different hours 3, 6, 9, 12, 15, 18, 21 and 24 P.m. A practical and realistic study was conducted. Three values of aspect ratio are used 30, 15 and 10 for the presence of air between the panels and in the presence of the argon gas for aspect ratio, 10 were practically investigated. The experimental results confirmed that using of the double glass with the presence of air as a medium for heat transfer between the two panels could be reduced the amount of heat transferred compared to that of single glass between (45-78), (54-85)and(58-88)%, while for argon it was (60-91)%.


Article
Sub-Cooling Auxiliary System for Performance Enhancement of Main Refrigeration System
استخدام منظومة تبريد مفرط ثانويه لتحسين اداء منظومات التبريد الرئيسية

Authors: Mustafa W. Hamadalla --- Fawziea M. Hussien --- Ahmed J. Hamad
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2015 Volume: 33 Issue: 8 Part (A) Engineering Pages: 1798-1812
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In presentwork, a sub-coolingauxiliary system is integrated with vapour compression refrigeration system to predict the performance characteristics and energy saving of the system. An experimental investigation was performed to determine the performance parameters at various operating conditions using two types of refrigerants, R-134a and zeotropic mixed refrigerant R-404A.Investigating the results hasshowed that, the enhancement in performance of the refrigeration system with sub-cooling circuit compared with that for system without sub-cooling for R-134a was about 5% increase in RE, 14% optimization in COPand 2.8% energy saving for different thermal loads applied on the evaporator.While for R-404A, the increase in RE was 4%, the optimization in COP was about 13% and 3.7%energy saving. There is a significant improvement in the performance of the system with R-404A compared with that forR-134a at the same operating conditions.

تتضمن الدراسة الحالية استخدام منظومة تبريد انضغاطية ملحق بها منظومة تبريد مفرط ثانويه لدراسة خصائص الاداء ومقدار التوفير بالطاقة للمنظومة. تم اجراء استقصاء تجريبي لحساب برامترات الاداء في ظروف تشغيل مختلفة باستخدام نوعين من وسائط التبريد, R-134aووسيط مختلط زيوتروبي R-404A عندما تشغل المنظومة بدون ومع دورة تبريد مفرط ثانويه. تحليل النتائج قد أوضح بان مقدار زيادة الاداء للمنظومة مع دورة التبريد الثانويه كان بزيادة 5% في سعة التبريد و 14% زيادة في معامل الاداء ومقدار التوفير بالطاقة 2.8% لوسيط التبريدR-134a عند احمال حرارية مختلفه, بينما للوسيط R-404A كانت بحدود 4% و 13% و3.7%على التوالي. لوحظ وجود تحسن ملموس في اداء المنظومة عندما تعمل بوسيط التبريد R-404A مقارنة بالوسيطR-134a عند ظروف تشغيل متشابهة.


Article
Improving Energy Saving in Conventional Pneumatic Systems by Using Air Booster Experimentally
تحسين كفاءة المنظومات الهوائية ذات الدوائر المفتوحة باستخدام مكبر الضغط عمليا

Authors: Jafar Mehdi Hassan --- Majid Ahmed Oleiwi --- Amer Abed Mansour --- Walaa Mousa Hashim
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2015 Volume: 33 Issue: 8 Part (A) Engineering Pages: 1012-2026
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Pneumatic actuators are widely used in industry and many other applications, whereas low energy efficiency has been recognized as a critical drawback compared with corresponding hydraulic and electrical actuators. The paper presents a study to improve the performance and energy efficiency of the traditional pneumatic drive with vertical load 50N, by added air booster type IPR (Input Pressure Reduce) to the.Four supply pressures used 2, 4, 6 and 8 bar, compared with the traditional control of the motion of the asymmetric cylinder in which maximum energy saving obtained at 6 bar16.7%.

للمشغلات الهوائية تطبيقات واسعة في المجالات الصناعية والمجالات الاخرى وذلك لما يميزها عن المنظومات الاخرى حيث تتميز بانها خفيفة الوزن،بيئة نظيفة،رخيصة الثمن مقارنة مع المنظومات الهيدروليكية.في هذا البحث تم دراسة طريقة جديدة في تحسين كفاءة المنظومة الهوائية ولما لها من مردود في تقليل معدل الصرف للطاقة من خلال ربط مكبرضغط الهواء عند مدخل الصمام لدائرة هوائية بحمل عمودي 50N واعادة تدوير هواء العادم للمكبر عند مدخل المشغل ولضغوط تجهيز مختلفة 2،4،6،8 بار حيث تم الحصول على اعلى توفير بالطاقة عند 6 بار وبمقدار 16.7%.


Article
SEWAGE WATER HEAT RECOVERY: A PROPOSED STUDY AS AN APPLICATION OF ENERGY SAVING IN IRAQ
استرداد الطاقة من مياه الصرف: دراسة مقترحة كأحدى تطبيقات حفظ الطاقة في العراق

Author: Tawfeeq Wasmi M. Salih
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2017 Volume: 21 Issue: 1 Pages: 114-123
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

An Innovative technology is used to recover some of the thermal energy of wastewater released by washing section in a restaurant as one of the energy saving applications to reduce electrical energy consumption for heating, as well as saving money. This research suggests using heat exchanger to recover heat from the sewage hot water (about 45 oC) to reheat the dining room for a proposed restaurant, and this will supply up to 8 Tons of heating load and will reduce the electrical energy that used to heat the place up to 44%. This technology within the system routes the passive energy conservation and considers another step on the way of sustainability.

تم استخدام تقنية جديدة لاسترداد بعض من الطاقة الحرارية للمياه المصروفة للغسل في المطاعم كاحدى تطبيقات حفظ وتوفير الطاقة للحد من استهلاك الطاقة الكهربائية للتدفئة، فضلا عن توفير المال. يقترح في هذا البحث استخدام مبادل حراري لاسترداد الحرارة من مياه الصرف الصحي الساخن (حوالي 45 درجة مئوية) لتسخين قاعة المطعم المقترح، وهذا سوف يوفر 8 طن كحد اقصى من حمولة التدفئة وسوف يقلل من الطاقة الكهربائية المستخدمة للتدفئة بحدود 44٪. هذه التقنية تاتي ضمن طرق حفظ الطاقة السلبية وتعتبر خطوة أخرى على طريق الاستدامة.


Article
EXPERIMENTAL STUDY ON THERMAL PERFORMANCE OF GLAZED ROOF WITH PHASE CHANGE MATERIALS AS AN APPLICATION OF ENERGY CONSERVATION IN RESIDENTIAL BUILDINGS

Authors: Hayder Mohammad Jaffal --- Tawfeeq Wasmi Mohammed --- Marwa Hamid Wasmi
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-3) Pages: 49-59
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The majority of electric energy that supplied to a residential house is consumed by air-conditioning during both summer and winter. Thus it has a major impact on the greenhouse gases and climate. Thermal energy storage systems using phase change materials (PCMs) in building elements has become a reliable solution for energy saving. The present study assists for the ‎utilization of PCMs in the roof of residential buildings to absorb the heat comes from solar ‎radiation during the daytime and releasing it to the inside nightly. The building considerations ‎as well as thermo-physical properties of PCMs have been taken and measured experimentally. ‎Results have shown that these materials have a good potential for reducing energy demand ‎and satisfy comfortable thermal conditions. The experimental data ‎show that the indoor temperature increases by 4-7 oC in the winter compared to that ‎measured in a traditional one. Furthermore, a simulation program depended on degree-days ‎method explained that the energy consumption could be saved up to 70%. Thus PCMs could ‎submit encouraging suggestions toward the sustainability.‎


Article
Design of Shell and Tube Heat Exchanger for Air Conditioning-Water Heating Hybrid System

Authors: Mohammed Jawad Yaseen --- Ahmed F. Atwan --- Alaa H. Shneishil
Journal: Journal of Education for Pure Science مجلة التربية للعلوم الصرفة ISSN: 20736592 Year: 2017 Volume: 7 Issue: 4 Pages: 1-15
Publisher: Thi-Qar University جامعة ذي قار

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Abstract

AbstractThe use of air conditioning-water heating hybrid system for heating, cooling and hot water ofbuildings, has significantly importance for energy saving. It has been proposed a system to recoverthe waste heat of refrigerant after leaving the air conditioning system condenser in the heating modeand the waste heat of refrigerant after leaving the air conditioning system compressor in the coolingmode to heat water for domestics or other needs. Shell and tube heat exchanger has been designed asa refrigerant-to-water heat exchanger located between the condenser and the expansion valve in theheating mode and between the compressor and the condenser in the cooling mode. The simulationprogram of heat exchanger has been built by using (MATLAP) in order to determining the heattransfer parameters and the temperature difference between the inlet cold water and outlet hot water,the results show that the effectiveness decrease with increase of water mass flow rate, while increasewith increase of tube length. As the tube length (15) m, the outlet hot water temperature from heatexchanger is (60.94) °C, for water mass flow rate (0.15) kg/s, and this value decrease exponentiallyand reach to about (7.528) °C, for water mass flow rate (2) kg/s, while for tube length (5) m, thesevalues ranging between (43.92) °C, to (1.234) °C, respectively.


Article
Energy Saving Using Intelligent Controller Based on Fuzzy Logic Control
حفظ الطاقة باستخدام مسيطر ذكي اعتمادا على السيطرة بالمنطق المضبب

Authors: Krikor S.Krikor --- Abduljabbar O.H Alshammery
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2012 Volume: 30 Issue: 6 Pages: 920-938
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

To reduce the impact of the high current on the power grid from the start process of the large induction motor and eliminate the negative influences of traditional reduced voltage start on the electronic and mechanical equipments and enhance the ability of the energy saving of the system. We studied and improved the intelligent soft start of such motors, this paper presents the design of intelligent soft starting controller in viewpoint of energy saving for power electronic systems. The proposed controller was compared through experimental studies under identical conditions with the thyristor soft starting controller (conventional controller). The performance comparison is made on the aspects of power quality and energy saving advantages. It is found thatthe proposed controller has superior operating and performance characteristics as compared to the conventional one.

من أجل تقليل تأثير التيار العالي في شبكة القدرة من جراء عمليات التشغيل الابتدائي للمحرك الحثي ذو القدرة العالية وحذف التأثيرات السلبية للطرق التقليدية لتقليل فولتية البدء في الاجهزة الميكانيكية والالكترونية وأمكانية تحسين حفظ الطاقة للنظام، نقدم دراسة وتحسين بدء تشغيل سلسوذكي لهذه المحركات، هذا البحث يقدم تصميم مسيطر ذكي لبدء التشغيل من وجهة نظرحفظ الطاقة لانظمة القدرة الالكترونية. المسيطر المقترح قورن من خلال الدراسات المختبرية تحت ظروف متطابقة مع مسيطر بدء تشغيل سلس تقليدي يعمل بالثايروستور، قورن الاداء من جوانب مميزاتكمية القدرة وحفظ الطاقة ووجد ان عمل وخواص الاداء للمسيطر المقترح يعمل بشكل ممتاز مقارنةمع المسيطر التقليدي.


Article
STUDY THE ECONOMICAL AND OPTIMUM THERMAL INSULATION THICKNESS OF BUILDING WALLS FOR ENERGY SAVING IN IRAQ
دراسة الظروف المثلى و الاقتصادية لسمك الجدران العازلة لتوفير الطاقة في العراق

Authors: Mustafa S. Mahdi مصطفى صباح مهدي --- Anees A. Khadom أنيس عبدالله كاظم
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2015 Volume: 8 Issue: 4 Pages: 813-818
Publisher: Diyala University جامعة ديالى

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Abstract

In hot climatic countries such as Iraq, a great amount of energy is consumed in air-conditioning. Environmental effect of energy consuming and the increasing cost of energy, give special interest in order to overcome the day by day increasing energy demand. Therefore the optimum insulation thickness for building was studied in this work to reduce the energy losses in three different climatic city of Iraq; Mosul, Baghdad and Basrah. Cork was used as an insulation material in present work. The optimization based on ten years life cycle cost analysis. As a result; significant energy saving is gained; saving of 10573 IDper square meter (about 10$/m2) of the wall in Basrah can be obtained annually when the optimum insulation thickness is applied.

في الدول ذات المناخ الحار مثل العراق, كمية كبيرة من الطاقة تستهلك للتكييف. الأثر البيئي لاستهلاك الطاقة وتكاليف الطاقة المتزايدة, يعطي اهتمام خاص من اجل التغلب على الطلب المتزايد بشكل اليومي للطاقة. ولهذا تم دراسة سمك العزل الأمثل للأبنية في هذا العمل للحد من الخسارة في الطاقة لثلاثة مدن عراقية مختلفة مناخيا: الموصل وبغداد والبصرة. حيث تم استخدام الفلين كمادة عازلة في هذا العمل. الدراسة بنيت على تحليل التكاليف لدورة حياة أمدها عشرة سنين. النتائج توضح إن هناك مقدار كبير من الطاقة يمكن توفيرها, مقدار 10573 دينار عراقي لكل متر مربع من الجدران (حوالي 10 دولار لكل متر مربع) يمكن توفيره في مدينة البصرة عند تطبيق سمك العزل الأمثل.


Article
Experimental Investigation of Heat Reduction through Walls Using Phase Change Material

Authors: Osama Rafie Labed --- Mustafa B. Al-hadithi --- Obaid T. Fadhil
Journal: Anbar Journal of Engineering Sciences مجلة الأنبار للعلوم الهندسية ISSN: 19979428 Year: 2018 Volume: 7 Issue: 3 Pages: 245-251
Publisher: University of Anbar جامعة الانبار

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Abstract

The reducing of heat gain through the outer walls of the buildings in summer will contribute in reducing the air conditioning costs. This is one of the best features of design requirements nowadays. To achieve this, the phase change materials (PCM) can be used as an embedded material in the walls to reduce heat transfer. The paraffin wax is one of the common materials used as a PCM in the building walls. The paraffin wax is used in this study with (20%) volume percentage in the external layer of the treated wall. In the present work, the treated wall (with embedded wax in the wall) and non-treated walls have been experimentally investigated. Two Iraqi wall models were employed to run the experiments, whereby these models were exposed to an external heat source using (1000 W) projector for each model. The temperatures were recorded at different locations in the walls during the charging and discharging periods. The results showed that the temperature of the internal surface for the treated wall was lower than that of the non-treated wall at the end of the discharging period (6 hr) where the temperature difference between the treated and non-treated walls was reached (1.6℃).

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