Thermal and geometrical assessment of parabolic trough collector-mounted double-evacuated receiver tube system

This paper particularly aims to highlight the necessity of optimal geometrical design considerations of a parabolic trough collector (PTC)-mounted receiver tube in view of efficient operation and high-end performance. Many investigations, analysis, and validation have been done in this regard as solar energy-based PTC now a commercially mature technology acknowledges a variety of role in the form of power generation and other thermal applications. This article identifies the optimal rim angle corresponding to its tube size as required for high exergetic gains. Almost six receiver tubes, distinct in terms of dimensions and number of covers, are compared for their best results to be mounted on adequate geometry with different rim angle (40 degrees, 80 degrees, and 120 degrees). A significant variation of flow rate (i.e., 16 to 216 L/h) and inlet fluid temperature (i.e., 323 K, 423 K, 523 K, 623 K, and 723 K) has been extensively detailed about high energy and exergy retrieval from the system. The study reports that all the favorable results are found with the receiver tube having a diameter of 0.027 m and a double envelope, compared to other design considerations. Results show that as the flow rate increases energy efficiency also increases up to some extent along with increasing receiver tube temperature. The highest energy and exergy efficiency are reported to be 79.4% and 45.9%, respectively, with 80 degrees being the optimal rim angle for a 5.7-m-wide parabolic aperture. This article also takes care of levelized cost of energy of the proposed system, and it has been reported as 0.0372 $/KWh along with a payback period of 8.2 years. [GRAPHICS] .

Automated summary

This study identifies the optimal design considerations for a parabolic trough collector (PTC)-mounted receiver tube to achieve high energy and exergy efficiency, with a focus on rim angle and tube size. Results show that a receiver tube with a diameter of 0.027 m and a double envelope, mounted at an optimal rim angle of 80 degrees, yields the best energy and exergy efficiency. Increasing flow rate enhances energy efficiency, and higher receiver tube temperature contributes to efficiency to a certain extent.