The present work deals with an experimental investigation of charging and discharging processes in thermal storage system using a phase change material PCM. Paraffin wax was used as the PCM which is formed in spherical capsules and packed in a cylindrical packed column which acted as an energy storage system. Air was used as the heat transfer fluid HTF in thermal storage unit. The effect of flow rate and inlet temperature of HTF on the time of charging and discharging process were studied. The results showed that the faster storage of thermal energy can be made by high flow rate of heat transfer fluid HTF and high inlet temperature of heat transfer fluid. It was found that at 65°C HTF inlet temperature, the melting and solidification processes accelerated by 27.9% and 57.14% respectively, when the flow rate was increased from 9 to 24 L/s. Also, when the HTF inlet temperature changed from 65°C to 80°C, the time needed to complete melting process decreased by 38.8%.
Abstract:
Under the state scenario, fiscal policy will not be able to use the oil surpluses optimally and economically and society, as long as these surpluses are not directed by public expenditure towards new productive investments and by following the path of fiscal policy after one year 2003 and until 2013 we note that it is based on the method of spending (excessive) consumption, and did not take any action towards the budget deficit planned at the beginning of the fiscal year, and the actual surplus at the end of the fiscal year, which represents the highest expenditure in the budget, Salaries and wages of workers in various government agencies with the expansion of spending on the security side.&n
... Show MoreThe research included five sections containing the first section on the introduction of the research and its importance and was addressed to the importance of the game of gymnastic and skilled parallel effectiveness and the importance of learning, but the problem of research that there is a difference in learning this skill and difficulty in learning may be one of the most important reasons are fear and fear of falling and injury, And a lack of sense of the movement of the movement is one of the obstacles in the completion of the skill and the goal of research to design a device that helps in learning the skill of descending Almtor facing with half a cycle according to the typical locomotor track on the parallel device of the technical men'
... Show MoreThe capital banking foundation stone upon which the bank in the practice of business activities, the more capital a good financial adequacy of the increased bank's ability to grant credit and expand the various activities and provide a safety element for depositors and other sources of funding to achieve profits and increase the trading volume of the shares, causing the rise the rate of return for the shares of banks and have the Central Bank as head of the banking system by issuing instructions capital increase banking, according to the requirements of economic development and increase gross domestic product by supporting investment projects that are financed through banks, the research aims to show the extent of the banks commitment to
... Show Morethe digital public relations aim at make the workers getting the necessary information about the governmental institutions where they work and the enveronment surrounding them. it also tries to let the workers get the special knowlege of tthe publich relations and their jobs like the works of planning , arranging the active communication and executive skills needed in their writing , editing , special art skills for designing , production and technological skills to deal with the computer.
the problem of the research includes some questions as :
1- what are the uses achieved by degetal public relations workers at Iraqi universities (Baghdad, Mustansiriya, and Iraqi)
2- what are the tools used to apply digital public relations
Idioms are a very important part of the English language: you are told that if you want to go far (succeed) you should pull your socks up (make a serious effort to improve your behaviour, the quality of your work, etc.) and use your grey matter (brain).1 Learning and translating idioms have always been very difficult for foreign language learners. The present paper explores some of the reasons why English idiomatic expressions are difficult to learn and translate. It is not the aim of this paper to attempt a comprehensive survey of the vast amount of material that has appeared on idioms in Adams and Kuder (1984), Alexander (1984), Dixon (1983), Kirkpatrick (2001), Langlotz (2006), McCarthy and O'Dell (2002), and Wray (2002), among others
... Show MoreThe research aimed to know the effect of the Parashot strategy in developing the reading comprehension skills of first-grade intermediate students in reading. The researchers put the following two null hypotheses: There is no statistically significant difference at the level (0.05) between the average scores of the experimental group students who study the subject Reading with the Parashot strategy in the pre and post-tests in developing reading comprehension skills as a whole. There is no statistically significant difference at the level (0.05) between the average scores of the experimental group students who study the reading material using the Parashot strategy and the average scores of the control group students who study the same subje
... Show MoreThe continuous technical development in the means of communication and information technologies has led to an increase in competition in the provision of service and product on the part of the organizations, as this competition does not know silence and stability on specific methods, but rather it is a world that is constantly moving and renewed in approaches, methods and approaches, and the focus of attention of integrated marketing communications practitioners are Customers, for them, organizations sell their goods, products, services, and ideas, and with them, they become stronger in competition.
This scientific study aimed to identify the trends of the initiators towards the integrated marketing communications of (the Emirates Tel
There have been many advances in the solar chimney power plant since 1930 and the first pilot work was built in Spain (Manzanares) that produced 50 KW. The solar chimney power plant is considered of a clean power generation that needs to be investigated to enhance the performance by studying the effect of changing the area of passage of air to enhance the velocity towards the chimney to maximize design velocity. In this experimental and numerical study, the reduction area of solar collector was investigated. The reduction area that mean changing the height of glass cover from the absorbing plate (h1=3.8cm, h2=2.6cm and h3=1.28cm). The numerical study was performed using ANSYS Fluent software package (version 14.0) to solve go
... Show MoreSoil invertebrates community an important role as part of essential food chain and responsible for the decomposition in the soil, helps soil aeration , nutrients recycling and increase agricultural production by providing the essential elements necessary for photosynthesis and energy flow in ecosystems.The aim of the present study was to investigate the soil invertebrates community in one of the date palms plantation in Aljaderia district South of Baghdad, , and their relationships with some physical and chemical properties of the soil , as Five randomly distributed replicates of soil samples were collected monthly. Invertebrates samples were sorted from the soil with two methods, direct method to isolate large invertebrates and indirec
... Show MoreRenewable energy sources - realities of the present and future options
Many of the directories indicate that the global energy system begin with a period of transition from total dependence on fossil energy sources, particularly oil, Into a new era in which renewable energy sources play an important role in meeting the growing needs of energy demand. There are many factors that will contribute to the strengthening of this trend towards transformation, which also will decide how quickly this transformation of renewable energy systems effectively in the global system of energy demand.
These factors, In brief: the size of environmental pollution and cl
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