Heat transfer and thermodynamic performance of a parabolic trough receiver with centrally placed perforated plate inserts

Abstract

In this paper, a numerical investigation of thermal and thermodynamic performance of a receiver for a parabolic trough solar collector with perforated plate inserts is presented. The analysis was carried out for different perforated plate geometrical parameters including dimensionless plate orientation angle, the dimensionless plate spacing, and the dimensionless plate diameter. The Reynolds number varies in the range 1.02×10 4 ≤ Re ≤ 7.38 × 10 5 depending on the heat transfer fluid temperature. The fluid temperatures used are 400 K, 500 K, 600 K and 650 K. The porosity of the plate was fixed at 0.65. The study shows that, for a given value of insert orientation, insert spacing and insert size, there is a range of Reynolds numbers for which the thermal performance of the receiver improves with the use of perforated plate inserts. In this range, the modified thermal efficiency increases between 1.2 -8 %. The thermodynamic performance of the receiver due to inclusion of perforated plate inserts is shown to improve for flow rates lower than 0.01205 m 3 /s. Receiver temperature gradients are shown to reduce with the use of inserts. Correlations for Nusselt number and friction factor were also derived and presented.

Influence of optical errors on the thermal and thermodynamic performance of a solar parabolic trough receiver

“…Good agreement was achieved for heat transfer fluid temperature gain (ΔT) and collector thermal efficiency as shown in Table 2 and also in one of our previous investigations (Mwesigye et al, 2014a). …”

Thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with Cu-Therminol®VP-1 nanofluid

“…The fluid friction from the present study was validated with the friction factor correlations by Petukhov [66] given by Eq. (36) and a correlation from Mwesigye et al Present study Mwesigye et al [16] Gnielinski correlation [66] Present study Petukhov correlation [66] Mwesigye et al [16] Nu With the nanofluid models used, the Nusselt number correlations by Pak and Cho [67] and Mwesigye et al [37] in Eqs. (40) and (41) To have confidence in the receiver thermal model, the thermal efficiency values of this study were compared with those obtained in experimental investigations by Dudley et al [68] as shown in Fig.…”

“…Similar to previous investigations [11,16,37], this profile was obtained using ray tracing implemented in SolTrace, an open source ray tracing software developed by the National Renewable Energy Laboratory (NREL) [58]. In the ray tracing procedure, the sun shape was taken as Gaussian distribution with ζ sun = 2.6 mrad [58], the maximum number of sun generated rays was set to 10 8 , and the desired number of ray intersections was set to 10 6 .…”

“…Selected studies on heat transfer enhancement techniques in parabolic trough receivers include: The use of inserts inside the receiver's absorber tube was investigated by Mwesigye et al [16,17], the use of porous discs was studied by Ravi Kumar and Reddy [13]. In another study, Ravi Kumar and Reddy investigated the use of different fin configurations for heat transfer enhancement in a parabolic trough receiver [12].…”

“…Already a number of studies have shown that significant improvements in receiver thermal performance can be obtained with heat transfer enhancement [12][13][14][15][16]. Selected studies on heat transfer enhancement techniques in parabolic trough receivers include: The use of inserts inside the receiver's absorber tube was investigated by Mwesigye et al [16,17], the use of porous discs was studied by Ravi Kumar and Reddy [13].…”