The evacuated tube solar collector ETC is studied intensively and extensively by experimental and
theoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climate
from April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collector
consists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relation
between convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect of
tube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.e
closed and open flow) to evaluate the heat loss coefficient from tank and tubes, test the collector with various
aspect ratios (32.9 and 27.2). The enhancement in collector performance is studied by using two reflectors (Flat
Plate and Curved Plate) and nanofluid (Water-AL2O3).Theoretical work is run by software (Fluent 6.3), to compute
the velocity and temperature profiles within the tube, for different tube diameters, effect of tube junction angle and
stagnant region in the bottom of the evacuated tube. The experimental results shows that the heat loss coefficient
for tube is W/m2.K and for tank is W/m2.K, the maximum collector temperature is 79°C in winter and
99°C in summer, while that belong to nanofluid collector is 99°C in winter. The best tilted angle (optimum) of
evacuated tube is 41° annually. The collector efficiency increased when using nanofluid of (1, 0.6, 0.3)% volume
fraction as(28.4, 6.8, 0.6)% respectively. The efficiency decreases as (33, 62)% when decreasing tube aspect ratio
from 38.6% to 32.9% and 27.2% respectively. An increase of (16.9 and 7.08)% in collector efficiency is obtained
when using curved and flat plate reflectors respectively. From simulation the best junction angle of the tank is
22.5°. The stagnant region is influenced with changing heat flux, tilted angle and aspect ratio.
An experimental investigation has been made to study the influence of using v-corrugated aluminum fin on heat transfer coefficient and heat dissipation in a heat sink. The geometry of fin is changed to investigate their performance. 27 circular perforations with 1 cm diameter were made. The holes designed into two ways, inline arrangement and staggered in the corrugated edges arrangement. The experiments were done in enclosure space under natural convection. Three different voltages supplied to the heat sink to study their effects on the fins performance. All the studied cases are compared with v-corrugated smooth solid fin. Each experiment was repeated two times to reduce the error and the data recorded after reaching t
... Show MoreFabrication of solar cell prepared by thermal spray and vacuum thermal evaporation method on silicon wafer(n-type) and studying its efficiency. The film have been deposited on three layers(ZnO then CdS and CdTe) on Si and glass respectively.Direct energy gap was calculated and equal to (4.3,3.4,3)eV and indirect energy gap equal to (3.5,2.5,1.5)eV respectively . Efficiency was calculated for the cell of area 2cm2 it was equal to 0.14%.
This research is a case study to solve control problems in Al Rasheed edible oil factory fire tube boilers. they have hopes to develop a new control system to manage boilers operation. The suggestion is to use Zelio soft programmable relays instead of the unavailable old control units. Operation philosophy was studied through works of literature, operation manuals, and standards. Programmable logic control relay is proposed as an advanced selection than PLC's. Boilers operation is accompanied by operation risks. many boilers were exploded in Iraq for different reasons. Some problems are attributed to manual operation mistakes. Extensive work was done to understand the operation sequence, emergency shutdown, and faults causing the trips. A c
... Show MoreEnergy crisis and the requirements of health and feel good, all this renewed attention to the importance of natural lighting in all kinds of factories.
Research problem was how to achieve the plant's own natural outlets visual comfort and satisfaction of workers in Companies, the industries of cotton and general al-fedaa.
The research compuns address the impact of daylight to provide visual comfort in the factory. Indeed, the light must be treated very carefully, and natural lighting should be thinking from the perspective of the occupants of the plant and not wishing to view from the outsid
... Show MoreThe dye–semiconductor interface between N749 sensitized and zinc semiconductor (ZnSe) has been investigated and studied according to quantum transition theory with focusing on the electron transfer processes from the N749 sensitized (donor) to the ZnSe semiconductor (acceptor). The electron transfer rate constant and the orientation energy were studied and evaluated depended on the polarity of solvents according to refractive index and dielectric constant coefficient of solvents and ZnSe semiconductor. Attention focusing on the influence of orientation energies on the behavior of electron transfer rate constant. Differentdata of rate constant was discussion with orientation energy and effective driving energy for N749-ZnSe system.
... Show MoreA total of 45 voucher specimens of falcons which are deposited in the bird's collection of the Iraq Natural History Research Center and Museum (INHM) were reviewed. Mummified falcons were preserved as voucher study specimens and tagged with museum collection labels. In the current study, morphometrics of six species of the genus Falco Linnaeus, 1758: Lanner falcon F. biarmicus Temminck, 1825; Sacker Falcon F. cherrug Gray, 1834; Lesser Kestrel F. naumanni Fleischer, 1818; Peregrine Falcon F. peregrines Tunstall, 1771; Eurasian Hobby F. subbuteo Linnaeus, 1758 and Common Kestrel F. tinnunculus Linnaeus, 1758 were documented. These species were recorded previously in the ornithological literatures by several authors and deposited in t
... Show MoreA total of 45 voucher specimens of falcons which are deposited in the bird's collection of the Iraq Natural History Research Center and Museum (INHM) were reviewed. Mummified falcons were preserved as voucher study specimens and tagged with museum collection labels. In the current study, morphometrics of six species of the genus Falco Linnaeus, 1758: Lanner falcon F. biarmicus Temminck, 1825; Sacker Falcon F. cherrug Gray, 1834; Lesser Kestrel F. naumanni Fleischer, 1818; Peregrine Falcon F. peregrines Tunstall, 1771; Eurasian Hobby F. subbuteo Linnaeus, 1758 and Common Kestrel F. tinnunculus Linnaeus, 1758 were documented. These species were recorded previously in the ornithological literatures by several authors and deposited in t
... Show MoreA total of 45 voucher specimens of falcons which are deposited in the bird's collection of the Iraq Natural History Research Center and Museum (INHM) were reviewed. Mummified falcons were preserved as voucher study specimens and tagged with museum collection labels. In the current study, morphometrics of six species of the genus Falco Linnaeus, 1758: Lanner falcon F. biarmicus Temminck, 1825; Sacker Falcon F. cherrug Gray, 1834; Lesser Kestrel F. naumanni Fleischer, 1818; Peregrine Falcon F. peregrines Tunstall, 1771; Eurasian Hobby F. subbuteo Linnaeus, 1758 and Common Kestrel F. tinnunculus Linnaeus, 1758 were documented.
These species were recorded previously in the ornithological literatures by several authors and deposited in the
In this paper thermo-hydrodynamic characteristics were investigated experimentally for a new type shell-helical coiled tube heat exchanger used as a storage tank of closed loop solar water heater system. Triple concentric helical coils were made of copper tubes of (12.5mm OD and 10mm ID) with coils diameter of (207, 152.2, 97mm) for outer, middle and inner coils respectively. The experiments were carried out during a clear sky days of (March and April 2012). The parameters studied in this work are: history of average temperature of shell side of the storage tank, collector heat gain, heat rejected from coils to shell side of the storage tank, collector efficiency, thermal effectiveness of the heat exchanger (storage tank), and pressure d
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