Performance analysis of a minichannel-based solar collector using different nanofluids


Mahian O., Kianifar A., Sahin A. Z. , Wongwises S.

ENERGY CONVERSION AND MANAGEMENT, vol.88, pp.129-138, 2014 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 88
  • Publication Date: 2014
  • Doi Number: 10.1016/j.enconman.2014.08.021
  • Title of Journal : ENERGY CONVERSION AND MANAGEMENT
  • Page Numbers: pp.129-138
  • Keywords: Minichannel solar collector, Entropy generation, Nanofluids, Efficiency, THERMAL-CONDUCTIVITY, ENTROPY GENERATION, HEAT-TRANSFER, NATURAL-CONVECTION, EXERGY-BALANCE, EFFICIENCY, EQUATIONS

Abstract

In this paper, an analytical analysis has been performed to evaluate the performance of a minichannel-based solar collector using four different nanofluids including Cu/water, Al2O3/water, TiO2/water, and SiO2/water. The analysis of first and second laws is conducted for turbulent flow by considering the constant mass flow rate of nanofluid. The results are presented for volume fractions up to 4% and nanopartide size of 25 nm where the inner diameter of the risers of flat plate collector is assumed to be 2 mm. Analysis of the first law of thermodynamics reveals that Al2O3/water nanofluids show the highest heat transfer coefficient in the tubes while the lowest value belongs to SiO2/water nanofluids. The highest outlet temperature is provided by Cu/water nanofluids, and after that TiOdwater, Al2O3/water, and SiO2/water nanofluids are in ranks of second to fourth. The results of second law analysis elucidate that Cu/water nanofluid produces the lowest entropy generation among the nanofluids. It is found that although the effective thermal conductivity of TiO2/water nanofluids is less than Al2O3/water nanofluids, but the entropy generation of TiO2/water is lower than Al2O3/water. Finally, some recommendations are given for future studies on the applications of nanofluids in solar collectors. (C) 2014 Elsevier Ltd. All rights reserved.