Performance Analysis Of Ocean Thermal Energy Convention System Using Kalina Cycle And Uehara Cycle

The development of renewable energy is an important way to reduce fossil fuel consumption and CO2 emissions.In recent years,the development and utilization of marine renewable energy has received extensive attention.Among them,ocean thermal energy is a research hotspot in the present energy field because of high stability,abundant reserves,and the potential for power generation.The Organic Rankine Cycle(ORC)is one of the most widely used cycles in Ocean Thermal Energy Convention,but it has low efficiency and high cost.The Kalina cycle(KC)and the Uehara cycle(UC)use ammoniawater mixed working fluid,and the cycle structure has been improved,the cycle efficiency has also been greatly increased.This dissertation takes the Kalina Cycle and the Uehara Cycle OTEC systems as studying objects to analyze their thermodynamic properties based on working principles,calculation methods and mathematical models by programming use Delphi.State parameters of each point,seawater flow rate,seawater pumping power,system net power,and power generation efficiency in the Kalina Cycle and the Uehara Cycle OTEC systems are calculated.Equipment for the evaporator,condenser and seawater pump in the Kalina Cycle and the Uehara Cycle OTEC systems are selected.Effects caused by evaporating pressure,condensing temperature(the outlet temperature of condenser)and extracting percentage on thermodynamic performance in the Kalina Cycle and the Uehara Cycle OTEC systems are explored.Performance between the Kalina Cycle and the Uehara Cycle OTEC systems are compared,the reason for differences are analyzed.The following conclusions can be found from the performance research on Kalina cycle and Uehara cycle OTEC systems.Seawater pumping power is the major factor affecting efficiency in the Kalina Cycle and the Uehara Cycle OTEC systems,about 40%of power is taken by seawater pumping power in 10 MW OTEC system.The influence of evaporating pressure and condensing temperature on thermodynamic performance is different in the same cycle but similar in different cycles.Increasing extracting percentage can get higher performance in the Uehara Cycle OTEC system,but it exists limitation.Because of extracting percentage,the Uehara Cycle has 1.45% increased in system net efficiency and 2.44% increased in cycle thermal efficiency compared with the Kalina Cycle.