THERMODYNAMIC STUDY OF INFLECTION POINT OF SATURATED VAPOR CURVE FOR DRY AND ISENTROPIC WORKING FLUIDS

asme-orc2015 Tracking Number 43

In this paper, the definition of inflection point on saturated vapor curve of dry fluid and isentropic fluid was given according to the shape of the saturated curve of working fluids in a T-s diagram. On this basis, the model of near-critical region triangle was established. Using this model, the effect of inflection point on saturated vapor curve on performance of organic Rankine cycle(ORC) was studied when 38 kinds of dry and isentropic organic working fluids was adopted in ORC. The performance includes relationship between the inflection point temperature and the area of near-critical region triangle, the relationship between the exergy at the inflection point and the area of near-critical region triangle, and the relationship between the area of near-critical region triangle and reciprocal value of slope of saturated vapor curve. On this basis, if the type of heat source is taken into account, the theoretical analysis results show that heptane, cyclohexane, octane, nonane, decane, and dodecane are the suitable working fluids for open-type heat source utilization.