Evaluating the effect of ammonia-water dilution pressure and its density on thermodynamic performance of combined cycles by the energy-exergy analysis approach

Abstract

The purpose of this study is to investigate the significant effect of ammonia-water dilution pressure and density on the thermodynamic performance of ammonia-water combined cycle through energy and exergy destruction, enthalpy temperature, yields, and flow velocity. The energyexergy analysis is conducted on the ammonia water combined cycle and the Rankine cycle, respectively. Engineering Equation Solver (EES) software is utilized for performing such detailed analyses. Values and ratios regarding heat drop and exergy loss is presented in separate tables for different equipment. The results obtained by the energy-exergy analysis indicate that net power increases with the increasing ammonia-water dilution pressure in the boiler. This trend continues until pressure range reach in [169.3 - 180] bar and after that, it starts to decrease. In addition, the increasing of ammonia-water dilution pressure leads to reduction of boiler both exergy and total exergy destructions, it also results in an increment in the exergy performance coefficient (EPC). Moreover, it is also noticed that the combined cycle system improves its efficiency by about 5.81% compared with gas turbines.