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%.
Proved the validity of all mixtures or not to accept the bees and then resistant infection worm wax Minor has accepted honey bee colonies all mixtures beeswax with paraffin wax industrial all ratios used made ??of a mixture to DVD waxy full and used naturally in breeding Houdnth In store honey and pollen evendiversified Bravian and natural wax
The thermal and electrical performance of different designs of air based hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and
... Show MoreThe dynamics of a single condensing two-phase bubble of two different dispersed-continuous systems were studied. The systems were, CCl4 - water and CCl4 - 100% glycerol. Cinephotography was used to determine the change in height, diameter and time. These results were used to determine the experimental rise velocity of the bubble, which was compared with a theoretical one based on some equations used. It was found that the velocity of the first system remained almost constant, while it decreased gradually for the second system.
Segmented regression consists of several sections separated by different points of membership, showing the heterogeneity arising from the process of separating the segments within the research sample. This research is concerned with estimating the location of the change point between segments and estimating model parameters, and proposing a robust estimation method and compare it with some other methods that used in the segmented regression. One of the traditional methods (Muggeo method) has been used to find the maximum likelihood estimator in an iterative approach for the model and the change point as well. Moreover, a robust estimation method (IRW method) has used which depends on the use of the robust M-estimator technique in
... Show MoreInherent fluctuations in the availability of energy from renewables, particularly solar, remain a substantial impediment to their widespread deployment worldwide. Employing phase-change materials (PCMs) as media, saving energy for later consumption, offers a promising solution for overcoming the problem. However, the heat conductivities of most PCMs are limited, which severely limits the energy storage potential of these materials. This study suggests employing circular fins with staggered distribution to achieve improved thermal response rates of PCM in a vertical triple-tube heat exchanger involving two opposite flow streams of the heat-transfer fluid (HTF). Since heat diffusion is not the same at various portions of the PCM unit,
... Show MoreIn this paper, a national grid-connected photovoltaic (PV) system is proposed. It extracts the maximum power point (MPP) using three-incremental-steps perturb and observe (TISP&O) maximum power point tracking (MPPT) method. It improves the classic P&O by using three incremental duty ratio (ΔD) instead of a single one in the conventional P and O MPPT method. Therefore, the system's performance is improved to a higher speed and less power fluctuation around the MPP. The Boost converter controls the MPPT and then is connected to a three-phase voltage source inverter (VSI). This type of inverter needs a high and constant input voltage. A second-order low pass (LC) filter is connected to the output of VSI to reduce t
... Show MoreObjective: To evaluate biomarkers of insulin resistance and acute phase reactants in obese, overweight and lean subjects and investigate the associations among those biomarkers. Methodology: This cross sectional study included 158 subjects who were stratified into three groups. Group1 comprised 53 obese patients (BMI≥ 30 kg/m2); group 2 were 54 overweight subjects, and group 3 had 51 healthy lean (BMI
The features of the actor's performance in the ritual theater are of great importance and chief in theatrical work since the first emergence of the theater, as the features of the performance were embodied in all Iraqi theatrical performances, but they took personal privacy in some ritual performances because of their differences and similarities between the ritual theatrical performance and the ritual show Al-Khalis, who wanted the researcher to know the similarities and differences in the features of the ritual performance and in the theatrical performance, despite the many transformations that occurred in the theater and affected the features of the performance, but it remained an important and attractive link between the recipient, t
... Show MoreThe culture of theatre performance has a vital role in the process of reading the linguistic and visual signs of the performance. And the process of transforming a theatre performance from its original context into a new hosting cultural context starts from the actual reading of the text. Directors derives their new signs out of his personal culture, depending on the society where they lives and the culture that forms the social conventions, traditions and beliefs. The text is usually written within its own historical and temporal culture. The process of its production usually takes it away from its original culture, when it interprets the codes of the original writer and their visual and linguistic signs and instils new alternative sign
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