Performance enhancement of centrally finned twist inserted solar collector using corrugated booster reflectors

Performance enhancement of centrally finned twist (CFT) inserted solar collector using corrugated booster reflectors (CBR) have been approached experimentally. The experimental trials have been made with two different twist ratios (Y = 3 and 6) for typical twist (TT) and centrally finned twist (CFT) under same working conditions. The results were compared with the plain tube solar thermal collector (SC) with CBR and also with the plain tube SC with flat booster reflectors (FBR). The experimental result of the plain tube CBR SC has been verified with the standard equations and found the deviations within ±10.32% for Nusselt number and ±9.14% for friction factor. The CBR has 1.6% higher effective reflector area than the FBR. Hence, the CBR augmented the Nusselt number around 8.25% over the FBR. When compared to the plain tube CBR SC, the CFT of minimum twist ratio (Y = 3) offered 11.08% higher thermal efficiency. In addition, empirical correlations have been derived for predicting the Nusselt number and friction factor. The deviations of the predicted value from the experiment value fall within ±11.02% for Nusselt number and ±10.88% for friction factor. •Use of corrugated booster reflectors in solar collector fields is proposed.•Effective reflector area of CBR is 1.6% higher than FBR.•CBR with CFT of twist ratio 3 offered higher thermal efficiency than CBR with plain tube.•Empirical correlations are developed for Nusselt number and friction factor.