|
Author Costa i Sitjes, Clàudia |
Abstract This project aims to present a characterization of alternative refrigerants with a reduced Global Warming Potential (GWP) for the gradual replacement of hydrofluorocarbons (HFCs). In this contribution, a thermodynamic characterization of some hydrofluoroethers (HFEs) is presented, as the first step to study these fluids as possible substitutes of HFCs. This has been fulfilled by using different computational tools; in particular a specific molecular based equation of state, named soft-SAFT, has been used for the study of thermophysical properties. In addition to that, a basic refrigerant cycle simulation is carried out to assess the efficiency of these new refrigerants. To achieve these goals, a molecular model is developed to describe HFEs vapour–liquid equilibria, based on the analysis of the charge distribution in the molecule, calculated from the COSMO_ADF software from atomistic calculations. The model parametrization is carried out for selected HFEs and is validated describing the saturated densities and vapor pressures of these compounds. The thermodynamic characterization is completed by studying the surface tension using a specific treatment for the interfacial region, called Density Gradient Theory, included in the soft-SAFT code. Also, a specific treatment to describe the viscosity based on the Free Volume Theory is coupled to the equation. Once the HFEs characterization is done, several potential binary mixtures of HFEs with other compounds, such as alkanes, aromatics, alcohols, etc., are studied. A good agreement using theorical models is provided, adequately reproducing the experimental data using only one binary parameter. Finally, some of the studied fluids are used for a simulation of a basic vapor compression refrigerant cycle and compared with the 3rd generation refrigerant R410A in terms of the evaluation of the Coefficient of Performance (COP). |
|
|
Director Llovell Ferret, Fèlix |
||
|
Degree IQS SE - Undergraduate Program in Chemical Engineering |
||
|
Date 2020-02-17
|
