Performance of nanofluid-cooled shell and tube gas cooler in transcritical CO2 refrigeration systems

Abstract

Abstract The theoretical performance analyses of the nanofluid cooled shell-and-tube gas cooler in transcritical CO 2 refrigeration cycle have been done to study the performance improvement of gas cooler as well as CO 2 cycle using Al 2 O 3 , TiO 2 , CuO and Cu nanofluids and effects of various design and operating parameters. Use of nanofluid as coolant in shell-and-tube gas cooler of CO 2 cycle improves the gas cooler effectiveness, cooling capacity and COP without penalty of pumping power. The CO 2 cycle yields best performance using Al 2 O 3 –H 2 O as coolant in shell-and-tube gas cooler followed by TiO 2 –H 2 O, CuO–H 2 O and Cu–H 2 O. The maximum cooling COP improvement of transcritical CO 2 cycle for Al 2 O 3 –H 2 O is 26.0%, whereas that for TiO 2 –H 2 O is 24.4%, for CuO–H 2 O is 20.7% and for Cu–H 2 O is 16.5% for the given ranges of study. Study shows that the nanofluid may effectively use as coolant in shell-and-tube gas cooler to improve the performance of transcritical CO 2 refrigeration cycle.