Concentrating Solar Power Central Receiver Panel Component Fabrication and Testing FINAL REPORT

Abstract

Executive SummaryThe objective of this project is to complete a design of an advanced concentrated solar panel and demonstrate the manufacturability of key components. Then confirm the operation of the key components under prototypic solar flux conditions. This work is an important step in reducing the levelized cost of energy (LCOE) from a central receiver solar power plant. The key technical risk to building larger power towers is building the larger receiver systems. Therefore, this proposed technology project includes the design of an advanced molten salt prototypic sub-scale receiver panel that can be utilized into a large receiver system. Then complete the fabrication and testing of key components of the receive design that will be used to validate the design.This project shall have a significant impact on solar thermal power plant design. Receiver panels of suitable size for utility scale plants are a key element to a solar power tower plant. Many subtle and complex manufacturing processes are involved in producing a reliable, robust receiver panel. Given the substantial size difference between receiver panels manufactured in the past and those needed for large plant designs, the manufacture and demonstration on prototype receiver panel components with representative features of a full-sized panel will be important to improving the build process for commercial success. Given the thermal flux limitations of the test facility, the panel components cannot be rendered full size.Significance changes occurred in the projects technical strategies from project initiation to the accomplishments described herein. The initial strategy was to define cost improvements for the receiver, design and build a scale prototype receiver and test, on sun, with a molten salt heat transport system. DOE had committed to constructing a molten salt heat transport loop to support receiver testing at the top of the NSTTF tower. Because of funding constraints this did not happen. A subsequent plan to test scale prototype receiver, off sun but at temperature, at a molten salt loop at ground level adjacent to the tower also had to be abandoned. Thus, no test facility existed for a molten salt receiver test. As a result, PWR completed the prototype receiver design and then fabricated key components for testing instead of fabricating the complete prototype receiver.A number of innovative design ideas have been developed. Key features of the receiver panel have been identified. This evaluation includes input from Solar 2, personal experience of people working on these programs and meetings with Sandia.

An optimisation study of a solar tower receiver: the influence of geometry and material, heat flux, and heat transfer fluid on thermal and mechanical performance

“…Clips were welded to the receiver's tubes and used to direct the receiver along its axis as the tubes expanded and shrank throughout the heating process. Contact with cold clips may allow a heat leak or produce cold spots in the morning that will freeze the salt and stop the system [47]. In this study, the effect of adding internal fins was investigated with consideration of the distance between clips (S), as shown in Figure 35, and by obtaining the thermal stresses and the displacement of the tube.…”

Longitudinal supports shape influence on deflection and stresses in solar receiver tubes

“…The information regarding how the tubes are guided is scarce in the literature. McDowell and Miner [2] indicated that clips are fabricated using a machined metal piece and a piece of tube stock, (see Figure 1a). Going through the clip, the guiding rods are fixed to the receiver frame, allowing the clips to slide [3].…”

Influence of longitudinal clips in thermal stresses and deflection in solar tubular receivers

“…To prevent excessive panel warpage and bowing (Radosevich and Skinrood, 1989), caused by the thermal gradients, tubes are attached to the receiver structure by longitudinal supports (McDowell and Miner, 2013), called clips (Fig. 1).…”