Isobaric Heat Capacity Measurements of Supercritical R1234yf

Abstract

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%.