Nowadays, nanofluids are introduced as an effective technique for enhancing the thermal efficiency in solar collectors. In this work, the MWCNT/oil nanofluid with 0.8% nanoparticle mass fraction is investigated experimentally in a solar dish concentrator coupled to a hemispherical cavity receiver. The main objective of this research is to examine the effect of the nanofluid application for improving the solar thermal performance of the hemispherical cavity receiver. The results revealed that thermal efficiency of the hemispherical cavity receiver has averagely increased equal to 12.93%, using application of the MWCNT/oil nanofluid compared to the application of the basefluid. In the steady state periods, the average thermal efficiency of 76.23% and 67.50% were calculated for the hemispherical cavity receiver using the MWCNT/oil nanofluid and pure oil, respectively. It was conducted that the receiver heats gain and the thermal efficiency of the cavity receiver has a similar trend with the working fluid difference temperature. Two experimental models were suggested based on the overall performance versus Tin − Tamb Ibeam for the MWCNT/oil nanofluid and the pure oil. Finally, it is found that the use of the examined nanofluid is able to enhance the thermal performance of the examined collector about 13%. Also, in this study, group method of data handling (GMDH) artificial neural networks is applied in order to model the dependency of thermal efficiency and the cavity heat gain of the Hemispherical Cavity Receiver on the mentioned factors.
کلید واژگان :Experimental study; Hemispherical cavity; MWCNT/oil nanofluid; Oil ; Efficiency enhancement
ارزش ریالی : 600000 ریال
با پرداخت الکترونیک