Experimental verification of advantages of the S-shaped fin configuration was examined by Nikitin for use in a recuperator of a supercritical CO2 gas turbine cycle [2] and by Ngo as a hot water supplier of a residential CO2 heat pump system . More specific comparisons between numerical and experimental results were made by Utamura and Nikitin for a recuperator and a hot water supplier [5] with S-shaped fins. The deviations between numerical and experimental values were within experimental uncertainty or 5%, which is sufficiently small to conclude that numerical prediction about thermal performance of a heat exchanger with S-shaped fins by CFD code was validated by those experimental results.