Evaluation of recuperative tube‐in‐tube heat exchanger operating in cryogenic refrigeration process: simulation‐based transient study

Abstract

AbstractHeat exchangers are the critical components of refrigeration and liquefaction processes. In the current paper, thermal behavior of Joule‐Thomson refrigeration system, including counter current helically coiled tube‐in‐tube heat exchanger and expansion valve, is studied in unsteady state conditions. According to obtained results, heat inleak let to longer cooldown time and lower liquefaction efficiency. Moreover, there was a critical length for a tube‐in‐tube heat exchanger operating in the Joule‐Thomson cooling system. A heat exchanger with a length shorter than the critical length could not liquefy the high‐pressure gas. This critical length was named as cooldown length (LCD) here. Increasing the heat exchanger length up to LCD led to increase in cooldown time, while increasing the length higher than LCD had no considerable effect on cooldown time. The simulations indicated that longitudinal heat conduction did not have considerable effect on the performance of heat exchanger in unsteady state conditions. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.