5. Discussion
5.1. Flow in S-shaped fin configuration: laminar or turbulent
The Reynolds number for the S-shaped fin configuration is usually about 1500 < ReCO2 < 15,000 for CO2, and 100 < ReH2O < 500 for water. Although the Reynolds number at CO2 side is sufficiently large to be regarded as turbulent flow, the Reynolds number at the water side is small. However, the S-shaped fin configuration