Coil side heat transfer characteristics study for a helical-coil heat exchanger.

Helical coil heat exchanger has been widely used in water heating purpose due to its higher heat transfer performance. Parameters, such as coil number, Reynolds number, and coil pitch are known as the key to the heat transfer. However, there is relatively rare study to stress on the heat transfer characteristics under a fixed heat transfer area condition. In this study, an experimental apparatus for a helical coil heat exchanger was established to study the shell side heat transfer performance for both counter and parallel flow patterns. The experiment was conducted under various coil diameters, coil numbers, coil pitches, and coil heights, while restricting on the same heat transfer area. The results show that the coil side heat transfer coefficient strongly related to coil diameter, coil pitch, coil curvature, and the Reynolds number. The results also verified the influence of coil curvature and coil pitch to the heat transfer performance.