It has shown also that the long-term perfor-d by losses from the storage than losses from the collector. During the test period,temperatures on the collector performance is studied and results haveach a high efciency and high outlet water temperature even for elevatedsequently, long term system performance is estimated by using a devel-roposed model, accurate and gave a good agreement with experimentale heat transfer in the storage. Each com-fore testing the complete system in spring days. Ith selective black chrome coated absorber and a low wall conductanced in order to set up a high performance thermosyphon system. Journal homepage: www.eof thermosyphon solar water Thresults, allowed to describmances are strongly inue Keywords:Performance collectorStorage tankLong-term performanceNumerical investigationĪ glassed at plate collecthorizontal storage are component is tested separateleffect of different inlet wshown that the collector cainlet water temperatures.oped numerical model. Khaled Zelzouli, Amenallah Guizani, Chakib KerkenThermal Processes Laboratory, (CRTEn), Borj Cedria B.P N95 2050, Hammam Lif, Tunisi All rights reserved.Numerical and experimental investigatioheater The insulated box reduces heatlosses from the back and sides of the collector. The best selective absorbers present selec-tivity values over 10, denoting higher sunlight energy absorptionand lower thermal energy losses. For the collectors having high perfor-mances, its absorbers surfaces are coated with a special selectivematerial to maximize radiant energy absorption while minimizingradiant energy emission. The absorber is usuallymade of ametal sheet characterized by a high thermal conductivity withattached or integrated tubes. Plate solar collector consists of an absorber in an insulated boxwithtransparent cover sheets (glazing). These two systems are cforced circulation and natural convemosyphon systems are that they do nccessful solar technolo-ergy has dramaticallyot water by solar radi-eater designs used ford solar water heatingized into two groups:he advantages of ther-on pumps and control. Most solar wsingle family are the closed andsystems. Nowadays, worlds demandincreased furthermore, process to cation is yet expensive. introduced in their study, performance of solar systems employingSolar water heater is one of the mgies. Black chrome for selective absorbers and collector efciencyvs. For the complete system, thestoragemust be insulatedwith very low thermal conductivitymate-rials. Tor of selective absorber coated with black chrome is one of bestcollectors used for heating water. Hasan studied the effect of the hotwater storage tank volume and conguration on system efciencyand he concluded that there is no difference between the perfor-mances of vertical and horizontal storage tank systems, and Thermosyphonic systems are studied intensively bymany researches. Energy Convers M(2013),, are more reliable, and have a longer life than forced circulationsystems. Numerical and experimental investigation of thermosyphon solar water heater. Please cite this article in press as: Zelzouli K et al.
The technical performance and reliability of solar systems arekey parameters that can signicantly vary the productionof thermalĬollectors with colored absorber, that the at phighly selective coatings can reach stagnation temthan 200 C and they showed that the colored clower efciency than the typical black type collect0196-8904/$ - see front matter 2013 Elsevier Ltd.
Zelzouli).concluded that the efciency of a SWH system can be increasedby using a larger hot water storage tank or smaller collectors area. Recently, the International Energy Agency issued a TechnologyRoadmap for Solar Heating and Cooling which estimates thepotential for domestic hot water in Africa and the Middle East inthe range of 2 Ej/year.įor the long term calculation, a number of computer softwareprograms have been developed concerning the modeling andĬorresponding author. studied the solar collectors with colored aers and they concluded that selective colored absorbers are ein wider range of operating temperatures than absorbers with colorpaints of high emissivity. Late collectors ofperatures ofmoreollectors pors. Tunisia isone of these countries which characterized by a temperate and anabundant sunshine for the most periods of the year. A very good insulated storage and a highly efcientcollector leads to a protable system in all months of the year andmainly in the countries having good sunshine climate. The twomain parameters, toget a reliable system, are the storage insulation and the collectorperformances. Tot relyĮnergy and thus the cost effectiveness. Ost suof enollect hater hopeneategorction.
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