考虑蒸发器压降的有机朗肯循环性能分析

Performance Analysis of an Organic Rankine Cycle Considering Evaporator Pressure Drop

选取以R245fa为工质的地热有机朗肯循环(ORC)为对象,研究了蒸发器压降对系统性能的影响。结果表明:在给定蒸发温度下,随着蒸发器压降的提高,系统热效率和效率下降,压损功率增大,蒸发器成本先快速降低后降幅变小,存在最佳压降区间,使得系统能同时获得较高的效率和较低的蒸发器成本;随着蒸发温度的升高,蒸发器压降下降,而蒸发器成本提高,存在最佳蒸发温度区间,使得系统能同时获得较高的效率与较低的蒸发器成本;当热源温度升高时,蒸发器压降提高,且增幅逐渐增大;蒸发器成本随着板片面积的减小而降低,且降幅逐渐增大。

Taking the ORC system with R245 fa as working fluid driven by geothermal heat source as an object of study,the effect of evaporator pressure drop on the system performance was investigated.Results show that at a given evaporation temperature,both the thermal efficiency and the exergy efficiency of the system decrease and the pressure loss power increases with the rise of evaporator pressure drop,while the evaporation cost first decreases rapidly and then tends to be stable,indicating that there exists an optimal range of pressure drop where higher efficiency and less evaporator cost can be obtained simultaneously.The evaporator pressure drop decreases and the evaporator cost increases with the rise of evaporation temperature,and there exists an optimum range of evaporation temperature,where both higher efficiency and less evaporator cost can be achieved.With the rise of geothermal water temperature,the pressure drop of evaporator increases with rising increase rate.The evaporator cost reduces with decreasing size,and the decrease rate rises gradually.