Experimental study on the heat transfer performance of a molten-salt printed circuit heat exchanger with airfoil fins for concentrating solar power

Abstract

A novel printed circuit heat exchanger (PCHE) was proposed to improve the heat transfer performance of the molten salt in concentrating solar power (CSP). Channels with distributed airfoil fins and channels with straight fins were designed for the hot molten-salt side and the cold side, respectively. The heat transfer characteristics of the novel PCHE was experimentally investigated by using a ternary salt and a synthetic oil as the heat transfer fluids in the airfoil channel and the straight channel, respectively. The experimental data was firstly obtained at the salt temperature ranging from 198 °C to 254 °C and Reynolds number varying from 500 to 1548. Then, the heat transfer performance of the novel PCHE with airfoil fins was compared with that of the traditional PCHEs with straight fins and zigzag fins, respectively. The results show that the novel PCHE can achieve the highest heat transfer performance. In the end, two heat transfer correlations were developed to predict the heat transfer performance of the molten salt flowing in the airfoil channel. The results indicate that the two correlations have good agreements with the experimental data. The first correlation has an average deviation of 3.9% and a maximum deviation of 12% with the experimental data, and the corresponding values for the second correlation are 3.8% and 10.8%, respectively. The experimental results and correlations from this study can offer help to the design of realistic PCHEs with airfoil fins in the CSP plant.