Performance evaluation of solar parabolic trough receiver using multiple twisted tapes with circular perforation and delta winglet

Abstract

A parabolic trough collector (PTC) is one of the concentrating types of a solar collector working in the medium range of temperature from 100–400 °C, for this reason, the efficiency of the solar parabolic trough is less than other types of concentrating solar collector (Point focusing types) in terms of solar to thermal energy conversion, the improvement in efficiency is achieved by various passive heat augmentation techniques in the receiver tube. One of the promising passive techniques is twisted tape inserts used in the receiver due to its simplicity in design and the various possibility of geometric modification. This paper deals with the performance evaluation of the solar parabolic trough receiver system by using passive techniques in the receiver. The testing of the receiver of PTC was done by using multiple perforated twisted tapes with winglets having different perforation ratios ([Formula: see text]) of 0.05, 0.15, 0.25, twist ratios ([Formula: see text]) of 3, 4, 5 and wing depth ratios ([Formula: see text]) of 0.1, 0.2 and 0.3. The number of twisted tapes was fixed at 4. The examination was conducted for Reynolds numbers ([Formula: see text]) varying from 3000–21,000 using air as working fluid. The outcome shows that the use of perforation and winglet in twisted tapes augment the Nusselt number as compared to that of smooth twisted tapes. The maximum thermohydraulic performance ([Formula: see text]) of 2.40 is received by using multiple twisted tapes with perforation and winglet having [Formula: see text] = 0.3, [Formula: see text] = 3, and [Formula: see text] = 0.05 at the Re = 21,000. The correlations for Nusselt number ([Formula: see text]) and friction factor ([Formula: see text]) are also developed with ± 8.5% and ± 8.3% accuracy, respectively.

A review of different twisted tape configurations used in heat exchanger and their impact on thermal performance of the system

“…The behaviour of this flow structure with multiple longitudinal vortices differs from that of flows in a plain tube. Thapa et al [ 100 ] studied the performance of the parabolic trough receiver by using twisted tape. The author analysed the influence of the twisted tape on the performance of the system.…”

A review study on the performance enhancement of solar parabolic trough receiver by various passive techniques

“…They termed it as thermohydraulic performance or thermo-hydraulic performance parameter(THPP). 42 In present study authors conducted detailed literature survey and found that many researchers also developed correlation for heat transfer and friction factor ( ff) which can be used to predict and extrapolate the heat transfer and ff for a wide range of Re. Based on the correlations developed by various researchers, 35,[42][43][44][45][46] author conducted empirical analysis and also calculated thermo-hydraulic performance parameters for these studies.…”