Simulation and Performance Evaluation of Finned Tube Gas Cooler for Trans-Critical CO2 Refrigeration System

Carbon dioxide is one of the rediscovered sustainable options, as CFCs and HFCs are now in the list of regulated substances, to be phased out in time bound way. There are however various challenges to the successful use of CO2 as refrigerant. Cost effective and widely acceptable technology is demand of the time. Performance of trans-critical CO2 refrigeration systems is found to be sensitive to the gas cooler design. In the present work a detailed mathematical model is developed for a finned tube air cooled gas cooler and the same is validated using published literature. Subsequently, to achieve the lowest possible approach temperature, the performance of the gas cooler is analyzed for various air velocity and alternate pipe arrangements. The effect of increase in size of gas cooler to its performance is also studied.