Abstract—Refrigerators and heat pumps plays an important role in this modern world. Refrigerants are used as working fluid in the thermal systems. These refrigerants undergo phase change in evaporator to provide a cooling effect. Chlorofluorocarbons and Hydroflurocarbons are the commonly used refrigerants but their stability in the atmosphere and their effect on GWP and ODP is a concern. Because of the harmful effects of synthetic refrigerants on the environment, industries are now looking for technologies based on natural refrigerants. Because of non-toxicity, high availability in nature and some unique thermo-physical property CO₂ is considered as the replacement for synthetic refrigerants. This facts motivated many and has lead to the development of trans critical cycle where the condenser gets replaced by a gas cooler. Use of the gas cooler with heat rejection taking place with large temperature glide offers several unique possibilities such as such as simultaneous cooling and heating, heat pump drying, water heating, etc. Main difference of CO2 with other refrigerants is its low critical temperature. However this gives an advantage of high volumetric capacity, which makes the CO₂ systems more compact. Initially micro-channel heat exchangers are suggested as gas coolers for CO₂ systems, but its high manufacturing cost makes it economically non-feasible. The objective of this work is to carry out CFD studies on finned tube gas cooler for transcritical operation of CO₂ systems. Flow pattern, Temperature distribution and performance variations with different operating conditions (mass flow rate of CO₂, air velocity, etc.) are studied and validated by test data obtained from the literature.

Index Terms—CO₂, Gas cooler

Cite: Bronin Cyriac, A G Shaligram, and M D Nadar, "CFD Modelling of Finned Tube Gas Cooler for Transcritical Operatoon of CO₂ Systems," International Journal of Mechanical Engineering and Robotics Research, Vol. 4, No. 1, pp. 467-472, January 2015.