Isobaric Heat Capacity Measurements of Supercritical R1234yf

R1234yf (2,3,3,3-tetrafluoropropene) is a low global warming potential (GWP) replacement for R134a, a fluid commonly used as a refrigerant in domestic and automotive air conditioning systems and as a working fluid in organic Rankine cycles. The use of R1234yf in energy conversion cycles requires an accurate determination of its thermophysical properties, including the isobaric heat capacity (cP). Using a custom-made flow calorimeter, experimental cP measurements of supercritical R1234yf were made at temperatures T = 373.15 to 413.5 K and absolute pressures P = 3.5 to 10 MPa. The experimental apparatus was calibrated using R134a to increase the measurement accuracy. The heat capacity measurements of R1234yf were compared to available published experimental data and to values obtained from a multiparameter equation of state (EOS). The measured cP values agreed well with the EOS, providing an average absolute deviation (AAD) of 1.6%.R1234yf（2,3,3,3-四氟丙烯，2,3,3,3-tetrafluoropropene）是R134a的低全球变暖潜势（global warming potential, GWP）替代工质。R134a是家用及车用空调系统中常用的制冷剂，同时也是有机朗肯循环的工作流体。在能量转换循环中应用R1234yf，需要精准测定其热物理性质，其中包括等压热容（isobaric heat capacity, cP）。本研究采用定制化流动量热计，在温度T=373.15 K至413.5 K、绝对压力P=3.5 MPa至10 MPa的工况下，对超临界R1234yf开展了等压热容的实验测量。为提升测量精度，实验装置采用R134a进行校准。将R1234yf的热容实验测量结果与已公开的相关实验数据，以及通过多参数状态方程（multiparameter equation of state, EOS）计算得到的数值进行对比后发现，实测的cP值与多参数状态方程的计算结果吻合良好，平均绝对偏差（average absolute deviation, AAD）为1.6%。