A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
Abstract
The study aimed to identify the expansion in granting credit to Iraqi banking institutions and its impact on the financial position of Iraqi banks in terms of revenues, profits, expenses and property rights in banks, as the expansion in granting bank credit will correspond to an increase or decrease in some items of the balance sheet and the financial position of banks, so the problem of the current study It will be determined through whether the expansion of granting bank credit will affect the financial position of Iraqi banks or not by studying the selected research community of the 10 Iraqi banks listed in the Iraq Stock Exchange, The research sample included the u
... Show MoreAbstract: The researcher aims to highlight the historical frames of political development in royal regime era (1921-1949) and study its transitions on social-political aspect for the various periods during this consistent era of Iraq history. As some elements played an important role in shaping this era’s features ,as well as 2hat succeed it, which mainly affected the political progression’s configuration, such as : political culture role, social and cultural foundation, state policy essence and the unofficial institutions remarkable role in influencing public awareness and concerning it's relation to the state ,the clan and religious institutions. The researcher employed Alexis de Tocqueville’s evaluation criteria and indi
... Show Moreيستعرض المقال تطور مؤتمرات القمة العربية منذ أول قمة عام 1946 حتى قمة المنامة 2024. ويسلط الضوء على القضايا التي تناولتها القمم، مثل فلسطين، سوريا، والسودان. كما يشير إلى أهمية قمة جدة 2023 التي شهدت عودة سوريا للجامعة العربية. وتستعد بغداد لاستضافة القمة الرابعة والثلاثين في 17 مايو 2025، وسط تحديات إقليمية كبيرة. وتعد القمة فرصة للعراق لاستعادة دوره العربي وتعزيز التعاون المشترك لمواجهة الأزمات السياسية والاقتصادي
... Show MoreIs astronomy in the Abbasid era one of the sciences that Muslims developed at that time? The restriction of students at the hands of a large number of students, which increased the development and increase the value of monitoring mechanisms and their outstanding efforts in support and development of the Arab civilization of Islam
وقائع واوراق ندوة (السياسة الخارجية الامريكية في عهد اوباما) التي عقدها فرع الدراسات الدولية في 25 تشرين الثاني 2009
Prince Kikaus explained to us Conditions of writing and establishing .Then he touched upon the Conditions of the ministry and qualities that must be characterized Author and minister both need machines must be availabla in person if given these positions .he was creative in presenting his ideas which is not without judgment an knowledge.He had a distinct style in mentioned professions and administrative hierarchy As explained in his speech About the writer and his Correspondence and construction and writer position who has developed into a minister then he touched it to the cabinet system and what the minister should do.of qualities .and the importance of the post of minister who mentioned several points to him ou
... Show Moreأن الوعي الذاتي والمعرفة قد برزت أهميتها في الفكر السياسي الليبرالي الحديث وجاءت من أجل المناداة بأهمية الوعي في جوهر الفرد فقد بين أغلب المفرين وأبرزهم جون لوك وايمانويل كانط، أكد لوك بأن حالة الوعي الذاتي تكتسب بالتجربة من خلال الإحساس والتأمل او التفكير، فالعقل صفحة بيضاء خاوية ولا توجد فيها أفكار فطرية ولكن في نفس الوقت يؤكد على وجود قوة فطرية في العقل وليست أفكار يمكن ان تحول الأفكار البسيطة الى مركبة م
... Show Moreتعد الصهيونية المسيحية الداعم الابرز للسيادة الصهيونية اليهودية على القدس، ويستند هذا الموقف الذي تتخذه الصهيونية المسيحية الى مجموعة من المعتقدات التي يشكل الاعتقاد بالعودة الثانية للمسيح وتأسيسه لمملكة سعيدة تدوم لالف عام محورها، ليصبح الاهتمام بمستقبل الشعب اليهودي احد الاركان الاساسية لمعتقدات الاصوليون المسيحيون لاسيما الصهيونية المسحية، فالتفسير الحرفي للكتاب المقدس قادهم الى اعتقاد مفاده: ان عو
... Show Moreيهدف البحث الحالي الى استكشاف علاقات التفاعل والتاثير بين الاحتكام للمكانة والتوجه للفردية– الجماعية والدمج التنظيمي مستنداً على مزج اختلاف القيم الشخصية مع افكار نظرية الهوية الاجتماعية لبلورة نموذج البحث. وفي ضوء هذا تم صياغة عدد من الفرضيات التي توضح علاقات التفاعل ما بين ابعاد الاحتكام للمكانة والتوجه للفردية– الجماعية للتنبؤ بوجود الدمج التنظيمي. جمعت البيانات باستخدام استمارة الاستبيان ووزع
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