Development of operation principles and calculation methods for compression heat pumps using zeotropic mixtures as working fluids

Abstract

The article presents operation principles and calculation methods for compression heat pumps using zeotropic mixtures as working fluids. It proposes the principle and methodological provisions for achieving the minimum value of mean condensation and boiling temperatures difference by selecting the molar concentration value for the low-boiling component of the zeotropic mixture out of two components that are close in their physical properties, and taking into account saturation temperature change in the condenser and evaporator of the heat pump, depending on the relative amount of the boiled out mixture and limited heat capacity heated and cooled mediums temperature changes. The authors developed a thermal calculation model for flow tubular condensers and evaporators of the zeotropic mixture, which allows to take into account the intensity of heat exchange changes and temperature conditions depending on the continuously changing composition and flow regimes of the vapor-liquid mixture taking place in the following sequence: dispersed, circular wave and layered-plug flow modes.