Enhancing the Performance of Evacuated and Non-Evacuated Parabolic Trough Collectors Using Twisted Tape Inserts, Perforated Plate Inserts and Internally Finned Absorber

Abstract

Abstract:The thermal enhancement of parabolic trough collectors is a critical issue and numerous ideas have been applied in the literature on this domain. The objective of this paper is to investigate some usual thermal enhancement techniques for improving the performance of evacuated and non-evacuated receivers of parabolic trough solar collectors. More specifically, the use of twisted tape inserts, perforated plate inserts, and internally finned absorbers are compared with the reference case of the smooth absorber. The analysis is conducted with a developed and validated thermal model in Engineering Equation Solver. The collector is investigated for a typical flow rate of 100 L/min and for inlet temperatures between 50 • C and 350 • C with Syltherm 800 as working fluid. According to the final results, the use of internally finned absorber leads to the highest thermal efficiency enhancement, which is up to 2.1% for the non-evacuated collector and up to 1.6% for the evacuated tube collector. The perforated plate inserts and the twisted tape inserts were found to lead to lower enhancements, which are up to 1.8% and 1.5%, respectively, for the non-evacuated collector, while they are up to 1.4% and 1.2%, respectively, for the evacuated collector. Moreover, the pressure drop increase with the use of the thermal enhancement methods is investigated and the use of internally finned absorber is found again to be the superior technique with the performance evaluation criterion to be ranged from 1.5 to 1.8 for this case.

Healthy Climate and Energy Savings: Using Thermal Ceramic Panels and Solar Thermal Panels in Mediterranean Housing Blocks

“…The cost of the investment in the installation system of 72.5 m 2 of KaRo mats, including the substation and 20-mm diameter PPR tube circuits was 58% higher, therefore, the investment's amortization period could be calculated as shown in Table 11. To calculate the amortization periods, a cost of 0.132 €/kWh was applied [51]. As can be observed, the investments were amortized over the long term, between 15 and 23 years.…”

“…These systems present major energy and environmental advantages. They reduce CO 2 emissions in the atmosphere proportionately to electrical energy savings and they can rely on renewable energy [51].…”

Internal Flow in an Enhanced Tube Having Square-cut Twisted Tape Insert

“…Therefore, several efforts have been made to lower the pump duty, to achieve the required performance under several design constraints. Passive heat transfer enhancement methods, which are currently adopted by many researchers, mainly employ swirl devices with twisted tapes [16][17][18][19]. Twisted tape inserts are one of the popular techniques available, to enhance the heat transfer performance of heat exchangers, due to their high economic performance and easy installation.…”

Numerical Study of Heat Transfer Enhancement of Internal Flow Using Double-Sided Delta-Winglet Tape Insert

“…Several works are summarized hereafter. The passive heat transfer enhancement methods that are still used by the majority of researchers are swirl devices in the form of twisted tape [3][4][5], wire coil [6,7], helical screw [8,9], and vortex generators in the form of a winglet [10][11][12]. These were investigated under various parameters to determine the important factors that affect the performance of the heat exchanger.…”