Analysis And Optimization On The Kalina Cycle In Low-Temperature

Today, with the energy situation being more serious, more attention is given on low temperature waste heat. Kalina cycle as an important process for the recovery of low-grade energy is gradually coming into view. In order to promote the development and application of Kalina cycle, this article will simulate and analysis the Kalina cycle from thermodynamics and then improve the system. The main contents and conclusions are as follows:120 ℃ geothermal water is used as a heat source, the main parameters(Ammonia concentration, vapor pressure, heat source temperature) on system performance is analyzed from first law, second law and economics angle by establishing thermodynamic model of Kalina cycle. The results show that : when vapor pressure is constant, as the concentration increases, the thermal efficiency, exergy efficiency will first increases and then decrease, there is an optimal concentration giving an maximum efficiency. When concentration is constant, net output power will first increases and then decrease with the increasing of the vapor pressure, and there is an optimal vapor pressure on the system output power. The higher temperature of heat source and lower of cool source will make the system more favorable. The total exergy loss of the system will increase as the concentration increase and vapor pressure decrease. The evaporator, condenser and turbine account the main exergy loss of the system. In economic terms, under different pressures, the concentration has a different effects on heat exchanger. And on steam turbines, high pressure and low concentrations correspond a smaller size parameters.In order to take full advantage of the high temperature and pressure energy in Kalina cycle, in this paper, its system has been improved and one system which combines the ejector refrigeration cycle with Kalina cycle is proposed to provide power and cool. In order to analyze the impact of key parameters on the system performance, the system model has been established in this paper. The results show that : with vapor pressure increasing, thermal efficiency and refrigerating capacity will increase, while the net output power will first increases and then decrease. The higher temperature of heat source and lower of cool source will make the system more favorable. The refrigerating capacity will increase and net output power will decrease as the Ammonia flow, so the Ammonia flow is mainly determined by the cold and electricity demand.Finally, this article has completed the experiment system design of 25 k W, and the main components of the system are selected and analyzed.