Energy and Exergy Performance Analysis of Different Kalina Cycle Configurations

Abstract

The main challenge of using Kalina cycle system (KCS) is to make use of waste heat to produce electrical power or cooling effect. Thus reducing fossil fuel consumption and pollutants emission. This study is concerned with a theoretical performance analysis of different configures of Kalina cycle. Three configurations are studied which are a simple Kalina cycle and two modifications of the simple cycle (MKCS1) and (MKCS2). A binary fluid of ammonia and water (NH3-H2O) is used as the working fluid. The varying operating parameters include ammonia mass fraction at turbine inlet and maximum cycle pressure. The dryness fraction at separator inlet is assumed constant and equal 0.3 and the minimum cycle is also assumed constant at 3bar. The results show that the maximum thermal efficiency for KCS, MKCS1 and MKCS2 are 8.64%, 12.7% and 18.85% respectively at the same conditions maximum pressure (Pmax)=35bar, minimum pressure (Pmin)=3bar, dryness fraction (DF)=0.3, ammonia mass fraction (x)=0.85 and the temperature at turbine inlet is 160℃. The maximum exergy efficiency for KCS, MKCS1 and MKCS2 are 34.21%, 51.92% and 75.34% respectively at the conditions Pmax=40bar, x=0.85, DF=0.3 and Pmin=3bar. The maximum net output power for KCS is 0.21kW at Pmax=15bar and x=0.85, the maximum net output power for MKCS1 and MKCS2 0.28kW and 0.41kW respectively at Pmax=30bar and x=0.89. This is equivalent to a reduction in the diesel fuel consumption by about 9.1*10 -5 kgf/kWelec. Also it reduction the pollution especially CO2 about 2.91*10 -4 kgCO2/kWelec.