Accurate knowledge of the thermodynamic properties of different media is crucial in determining heat transfer behavior. Online databases calculate these properties using Equations of State (EOS), which in their turn are derived from experimental measurements. However, in the near-critical region, especially for newer fluids, only limited experimental data is available. This results in EOS with relatively large uncertainties, especially because the thermophysical properties vary drastically around a certain ‘pseudo-critical temperature’, illustrated in the figure. Therefore, experimental characterization of these thermophysical properties remains important.
The objective of this thesis is to fill in the gap in data of thermodynamic properties, more specifically the isobaric specific heat capacities (cp). A flow calorimeter, a device to experimentally determine cp-values, has been built in the previous year (see CAD drawing). However, the extensive experimental campaign on the test setup still needs to be performed. The cp-values of different newer low global warming potential (low-GWP) refrigerants need to be measured, for a large temperature and pressure range. In addition, these results should be compared with each other and with what is already available in literature, and newer more accurate EOS need to be determined. The data points will be used to construct the necessary equations of state in order to predict the thermodynamci properties of the fluids (thermodynamic model to be constructed).