Energy and exergy estimation for a combined cycle of solid CO2 production and NH3-H2O single effect absorption chiller

Abstract

In order to reduce the compression power, to use an integrated thermal-driven cycle, and to mitigate the CO2 content in the air, a new combined cycle of absorption chiller and vaporcompression refrigeration cycle to produce carbon dioxide dry ice was devised and analyzed. In this study, the energy and the exergy analyses of the combined cycle were presented. The combined cycle simulation was carried out by using EES (Engineering Equation Solver) program. The CO2 condensation pressure and the generator temperature were considered as key parameters. Results show that the total compression and pumping power using the present combined cycle can be reduced remarkably, amounting to 44.4 %, in comparison with that in the conventional ammonia cooling system. Most of the irreversibility occur in the absorption system and the irreversibility of the absorber has the largest portion. The temperature reduction of the solution or increase in the cooling water temperature can improve the irreversibility of the absorber. However, the latter decreases the irreversibility more than the former.