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%.
- Aim of the current research is to know the impact of guided discovery strategy sports communication skills among students in first grade average in mathematics.
- , Consisted sample of (58) a student from a school Baghdad Rusafa, divided in two groups, one experimental studied according to strategy discovery The second group studied the traditional way, the researchers built search tool (test communication skills sports), and using a number of statistical methods including : -
- Test (t - test) was used to independent samples to examine the match Mediterranean experimental and control groups and tested Levin (Leven - test
Allah Almighty has singled out women for some rulings, and made them unique to them, in terms of the provisions of menstruation, postpartum
چكيده
نماد در لغت معنى كه (اشاره ،رمز) ودر معنى ديگر مجموعه اى از نشانها، حركتها، حرفها يا كلمه هاى از پيش تعيين شده براى برقرارى رابطه يا مبادلهء پيام است. نماد در قران نيز در سورهء ال عمران آمده است: (قَالَ رَبِّ اجْعَل لِّي آيَةً ۖ قَالَ آيَتُكَ أَلَّا تُكَلِّمَ النَّاسَ ثَلَاثَةَ أَيَّامٍ إِلَّا رَمْزًا ۗ وَاذْكُر رَّبَّكَ كَثِيرًا وَسَبِّح
... Show MoreBooks of plans are a type of writing in Islamic history , its a type of work whose authors have strived to serve as a comprehensive historical encyclopedia, and they focused most of their attention on highlighting the various aspects of the history of Egypt. , Especially. urban side. And political, military, scientific, social , economic events.
they authors in this Type were not satisfied with that only, but they mentioned the stages of the development of architecture and what followed until their time
الديمقراطية في الفكر الاسلامي المعاصر وعلاقتها بنظرية الشورى
The essential objective of this study presents a analyzes of the combination of reality and fantasy in three dramas of Spanish author Alejandro Casona. "Trees die standing" (premiered in Buenos Aires in 1949), “Prohibited suicide in spring” (premiered in Mexico in 1937) and "The boat without fisherman" (premiered in Buenos Aires in 1945).
The first part is an introduction about the biography of Spanish author Alejandro Casona that will allow us to understand some peculiarities of his work in relation to the social historical context of his time.
In the second part of this study we have analyzed elements of reality and fantasy in the th
... Show MoreThe intellectual and revolutionary movements that have emerged since the beginning of the second half of the first century of the Islamic era did not appear suddenly, but must have preceded by a social consciousness, multi-forms, in the forefront of class awareness and religious awareness, and awareness was more painful, Of the society of the Arabian Peninsula - before Islam - feel it and suffer from it, a sense of injustice and tyranny, oppression and humiliation, and the destruction of dignity as well as poverty and hunger, and the injustice of tribal laws, and tyranny of each other and the tyranny of their heads on the tribes members and families belonging to this tribe or hill
Receipt date:9/1/2020 accepted date:11/24/2020 Publication date:12/31/2021
This work is licensed under a Creative Commons Attribution 4.0 International License.
the Nile River and the Renaissance Dam is one of the most prominent factors that had an important role in the nature of relations between Egypt - Ethiopia, as they contributed to building a relationship that has common characteristics through the nature of the i
... Show Moreالامن الجماعي في اسيا .. بقلم : لونيك فرو وار
The followers of philosophical lesson in Iraq discover steps and important stages through which the country had passed in , since the control of this thought in Arab Islamic civilization until recent time as well as touch the important changes that had happened on it