A novel Kalina power-cooling cycle with an ejector absorption refrigeration cycle: Thermodynamic modelling and pinch analysis

摘要

A new power and cooling cogeneration cycle is proposed that combines the Kalina power cycle and the ejector absorption refrigeration cycle with an ammonia-water mixture as the working fluid. The proposed system, Kalina power-cooling with an ejector cycle (KPCE), originates from the Kalina power and cooling cycle (KPCC) and introduces an ejector before the evaporator. Thermodynamic analyses from the viewpoints of energy efficiency, as well as comparisons between KPCC and KPCE under the same initial conditions, were conducted for the cycles' refrigeration output and thermal efficiency. Energy analysis results showed that the KPCE provides a performance improvement without greatly increasing system complexity. At the same power production level, the refrigeration output and thermal efficiency of KPCE is 13.5% higher and 17% more than KPCC, respectively. Energy losses due to inefficient heat recovery design of the system are identified by cross heat pinch analysis. All three preheaters of the system showed an inefficient design of heat recovery. After redesigning, power, and power-cooling efficiencies showed 7% and 4.3% increases, respectively. The effect of four important input parameters including three pressure levels and ammonia mass fraction on the KPCE performance are investigated to optimize the system. The optimized KPCE performance improved by 17.9% and 13.6% for power and power-cooling efficiency while the total annual cost of the system could decrease by 6.8%.