9113

8451

كارشناسي ارشد

مهندسي شيمي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي شيمي

1392

[چهارده]،89ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

غلامرضا اعتماد، مسعود حق شناس

18/4/93

نسرين اعتمادي، علي اكبر عالم رجبي

مهندسي شيمي

ID8451

90 Numerical investigation on the effects of nanofluids on efficiency of U tube evacuated tube solar collectors Amin Razeghi a razeghi@ce iut ac ir March 1 2014 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisors S GH Etemad etemad@cc iut ac ir M Haghshenas Fard haghshenash@cc iut ac irAbstractNowadays energy is an essential factor in economic growth of human societies Among all kinds ofenergy sources available solar energy is the most abundant Both nature and human kind inventeddifferent ways for using energy of sun Converting solar energy to heat is the simplest way to use it In the last decades different types of solar water heaters have been developed and used Heart of everysolar water heater is its solar collector Mainly two types of solar collectors are used flat plate solarcollectors and evacuated tube solar collectors In comparison to evacuated tube solar collectors flatplate solar collectors have more heat losses so it has less thermal efficiency especially in highertemperatures In this research filled type U tube evacuated tube solar collector has been chosen fornumerical simulations Effect of length diameter configurations of U tube in the collector thermalconductivity of filled material and CuO Al2O3 and TiO2 aqueous nanofluids as working fluid on heattransfer and thermal efficiency of solar collector have been studied It was been found that increasinglength diameter and thermal conductivity of filled material leads to an increase in thermal efficiencyof solar collector Among all five configurations of U tube in collector studied configuration in whichthe U tube is mounted vertically is the efficient Also when U tube was mounted horizontally thecollector has less efficiency compared to other configurations It has been revealed that usingnanofluid as heat transfer medium in the evacuated tube solar collector leads to an increase in thermalefficiency CuO nanofluid leads to an increase of about 13 8 percent in efficiency of solar collector Efficiency of CuO nanofluid is about 1 3 and 1 5 times for that of TiO2 and Al2O3 nanofluidsrespectively Due to reduction in heat capacities of nanofluids with increasing nanoparticleconcentration it can be deduced that heat capacity is a key factor in evacuated tube solar collectorswhen using nanofluids Key works solar energy evacuated tube solar collectors thermal efficiency and nanofluid

غلامرضا اعتماد، مسعود حق شناس

نسرين اعتمادي، علي اكبر عالم رجبي