Performance improvement and comparisons of CO2 based adsorption cooling system using modified cycles employing various adsorbents: A comprehensive study of subcritical and transcritical cycles.

• Four different configurations of adsorption cooling cycles are studied for improved performance for subcritical and transcritical cycles. • Detailed thermodynamic analysis is carried out for 5 different adsorbent materials for all the configurations. • Effect of various parameters are studied on system performance. • Out of all the adsorbents used, Maxsorb III showed better system performance. • Various co-relations have been developed for various intermediate temperatures and COP. In the present investigation, thermodynamic analysis of four different adsorption cooling cycles; basic, internal heat recovery, mass recovery, and heat & mass recovery cycles are carried out employing CO 2 as the refrigerant. The said investigation is done for five different adsorbent materials i.e. a highly microporous activated carbon (Maxsorb III), Maxsorb III based composite, Activated carbon fibre (ACF) A-20, BPL activated carbon (AC), and Norit AC. The study stretches the analysis from subcritical to supercritical zone for evaporator temperature ranging from −5 °C to 15 °C. For subcritical cycle, generator and condenser temperatures are varied between 65 °C to 91 °C and 20 °C to 30 °C, and for transcritical cycle, generator and gas cooler exit temperatures are varied from 90 °C to 120 °C and 35 °C to 40 °C, respectively. The maximum COP and specific cooling effect (SCE) achieved by incorporating both heat and mass recovery to the basic cycle are 0.305 and 105 kJ/kg, respectively. The improvement in COP and 2nd law efficiency of the same cycle w.r.t. other cycles are in the range of 7% to 84% and 38% to 77%, respectively for subcritical cycles. Similarly, for transcritical cycles, improvements in COPs of HMRC are in range of 17% to 75%. Analysis showed better system performance for Maxsorb III and it's composite as compared to other adsorbents. Various regression equations are developed to predict the different intermediate temperatures and COP for the mentioned modified subcritical and transcritical cycles. [ABSTRACT FROM AUTHOR]