R-410A and R-404A real gas thermodynamic relations and their application for predicting exergy efficiency in vapor compression heat pumps
(EN)
Loakim, V
(EN)
Stegou-Sagia, A
(EN)
Papadaki, A
(EN)
Enthalpy and entropy equations, as these resulted from the Martin-Hou Equation of State, are presented for the promising mixtures R-404A and R-410A that replace the HCFC-22 in refrigerator and heat pump systems. Based on these equations, a model was developed to simulate the relevant thermodynamic heat pump cycle for vapour compression systems. The variation of exergy efficiency factor, COP and exergy flow is outlined. Moreover focusing on the partial derivatives of pressure, on the real gas heat capacity at constant volume and on real gas heat capacity at constant pressure, useful characteristics such as sound velocity and isentropic exponents are derived and plotted in charts, for a wide area of state conditions.
(EN)
