Visualization of the Refrigerant Flow at the Capillary Tube Inlet of a Household Refrigeration System

Autores UPV
Año
CONGRESO Visualization of the Refrigerant Flow at the Capillary Tube Inlet of a Household Refrigeration System

Abstract

An experimental work aimed to visualize the refrigerant flow at the capillary tube inlet has been presented. In order to deepen the studies about the actual refrigerant conditions in this part of a refrigeration system, a novel experimental test bench has been designed and mounted on a high efficiency household refrigerator. The main results can be summarized as follow:  The analysis of the temperature profile leads to define the presence of subcooled liquid at the condenser outlet. However, further analysis, reveals that this conclusion is wrong.  Regardless the orientation of the filter and the capillary tube position inside it, the capillary is always sucking a mixture of liquid and vapor. In all the tested filters, the liquid level follows the capillary entrance demonstrating that filter is not operating as a liquid receiver. This visualization work cannot demonstrate by itself that the refrigerant has not fully condensated in the condenser; it only shows that there are two phases. Although a non-equilibrium condition could explain this observation, the analysis of the temperature profile and the null variation of subcooling when the refrigerant charge is varying point out a really null subcooling. Probably, the compressor would need a more restrictive capillary tube, but further woks are required to confirm this idea.