Performance improvement of a household freezer with a microchannel flat-tube evaporator

Abstract

Microchannel flat-tube heat exchangers (MCHX) have been introduced into refrigeration systems due to their high efficient heat transfer, lightweight and compact structure. In this work, a MCHX was introduced into a household freezer as the evaporator. The dynamic characteristics and performance were experimentally investigated and compared to the freezer with a traditional circular tube evaporator. Results showed that the refrigerant charge, compressor-on ratio, and daily power consumption of the freezer with the MCHX were reduced by 5.4%, 4.4% and 4.8%, respectively. In contrast to circular tubes, microchannel tubes in evaporators have a flattened rectangular with multiple flow channels. This design increases the surface area for heat transfer, allowing for enhanced heat transfer performance. The decreased refrigerant charge and good heat exchange performance for the MCHX evaporator contribute to a lower outlet temperature, improved cooling efficiency and lower power of the compressor. Results verified that the MCHX could be used as the evaporator in household freezers to reduce the power consumption and improve the system performance.