Liquid-based high-temperature receiver technologies for next-generation concentrating solar power: A review of challenges and potential solutions

To reduce the levelized cost of energy for concentrating solar power (CSP), the outlet temperature of the solar receiver needs to be higher than 700 degrees C in the next-generation CSP. Because of extensive engineering application experience, the liquid-based receiver is an attractive receiver technology for the next-generation CSP. This review is focused on four of the most promising liquid-based receivers, including chloride salts, sodium, lead-bismuth, and tin receivers. The challenges of these receivers and corresponding solutions are comprehensively reviewed and classified. It is concluded that combining salt purification and anti-corrosion receiver materials is promising to tackle the corrosion problems of chloride salts at high temperatures. In addition, reducing energy losses of the receiver from sources and during propagation is the most effective way to improve the receiver efficiency. Moreover, resolving the sodium fire risk and material compatibility issues could promote the potential application of liquid-metal receivers. Furthermore, using multiple heat transfer fluids in one system is also a promising way for the next-generation CSP. For example, the liquid sodium is used as the heat transfer fluid while the molten chloride salt is used as the storage medium. In the end, suggestions for future studies are proposed to bridge the research gaps for > 700 degrees C liquid-based receivers.