Experimental study on heat storage and corrosion properties of ternary carbonate salt-based ZnO nanofluids for solar thermal energy storage

Molten salts are important heat storage and heat transfer media in solar thermal power generation systems based on concentrating solar power (CSP) technology. In this study, ternary carbonate (Li2CO3: Na2CO3: K2CO3 with 31:34:35 mass ratio) nanofluids with ZnO nanoparticles were prepared and characterized, and their thermophysical and corrosion properties were investigated. The prepared ternary carbonate salt-based ZnO nanofluids exhibited good thermal stability, enhanced heat capacity, and reduced corrosivity. The average solid-state specific heat capacity of ternary carbonate nanofluids with 1.0 mass% of 30-nm ZnO increased by up to 16.56% and the average liquid specific heat increased by up to 21.61% compared to those of the base salt. The latent heat of the ternary carbonate salt with ZnO nanoparticles was reduced compared to the base salt. Meanwhile, the maximum corrosion mass gain and corrosion rate of austenitic stainless steel in nanofluids were 1.72 mg cm(-2) and 9.6 mu m y(-1) which decreased by 27.4% and 25.8% compared to the base salt, respectively. This work offers a good reference for design of the molten salt-based nanofluids with superior thermophysical properties and low corrosivity in CSP applications.

Automated summary

Molten salts are crucial in solar thermal power generation systems. A study has successfully prepared ternary carbonate nanofluids with ZnO nanoparticles, which show enhanced heat capacity and reduced corrosivity.