Energy and exergy analyses of nanofluid-filled parabolic trough solar collector with acentric absorber tube and insulato
- PDF / 3,536,823 Bytes
- 30 Pages / 595.276 x 790.866 pts Page_size
- 109 Downloads / 207 Views
Energy and exergy analyses of nanofluid‑filled parabolic trough solar collector with acentric absorber tube and insulator roof Ali Akbar Abbasian Arani1 · Farhad Monfaredi1 Received: 26 May 2020 / Accepted: 15 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract Increasing the energy demands has encouraged the development of novel archetypes solar receiver employed in sustainable energies. Parabolic trough solar collectors (PTSCs) attract researchers due to high thermo-hydraulic performance. The main goal of the present investigation is to design an efficient PTSC filled with nanofluid numerically using the finite volume method. The other aim is to compare the obtained numerical results of nanofluid simulation in PTSC the using single-phase mixture model (SPM) and the two-phase mixture model (TPM). In the first step, influences of using SPM or TPM on nanofluid simulation in absorber tube are investigated. Then, the influences of using an insulator roof and an acentric absorber tube on energy and exergy efficiency are studied. Consequently, in this step the optimum configuration is introduced. In the last step, effect of different nanofluid parameters (different volume fraction and various nanoparticles diameters) on the optimum configuration is investigated using TPM. Based on obtained results, for both conventional and novel PTSC, the obtained Nusselt number employing TPM simulation is more than that of SPM simulation. Also, it is found that using the novel PTSC leads to higher Nusselt number, energy efficiency, performance evaluation criteria, and outlet temperature for all studied Reynolds numbers. According to the results, the energy and exergy efficiencies of novel PTSC with an insulator arc angle of 70° and acentric value of 20 mm filled with nanofluid having a diameter of 20 mm and nanoparticles volume fraction of 1% are about 73.10 and 31.55% and are the maximum obtained efficiencies in the present study. Keywords Parabolic trough solar collector · Exergy efficiency · Insulator roof · Acentric absorber tube · Nanofluid · Twophase mixture model Nomenclature Aa Absorber tube surface APTSC Aperture of PTSC a Radiation constant ( a = 7.561 × 10−19 kJ m−3 K−4) ai Coefficients in thermal properties of Syltherm 800 oil estimations b Exergy transfer bq Exergy of the heat receiver C𝜇 Standard constant in the turbulent model cp Constant specific heat capacity c1 Standard constant in the turbulent model c2 Standard constant in the turbulent model C.PTSC Conventional PTSC c Speed of light in vacuum (2.998 × 108 m s−1) * Ali Akbar Abbasian Arani [email protected] 1
Department of Mechanical Engineering, University of Kashan, Kashan, Iran
D Coefficient of Einstein diffusion da Absorber tube outer diameter dg Glass cover outer diameter dnp Nanoparticle mean diameter Ė dest Destruction exergy Ė dest,Δp Destruction exergy due to the pressure gradient Ė dest, heat Destruction exergy due to heat transfer Ė loss Exergy loss Ė loss, heat Exergy loss due to heat transfer Ė los
Data Loading...
