4742 (RP-1094) - Coil Frosting and Defrosting Issues at Low Freezer Temperatures Near Saturation Conditions PDF

During the operation of industrial freezers, frost buildup contributes to coil heat transfer performance degradation due to the insulating effect of the frost layer and the resulting coil blockage. While the frosting problem has been extensively researched, no study has investigated the problem when the freezer is operating near saturated or under supersaturated conditions. Field observations of industrial freezer operation indicate that this is a common mode of operation and that the transition to supersaturated operation can easily occur if proper care is not exercised by either the refrigeration system designer or the freezer operator. Field observations also reveal that operating freezers under supersaturated conditions can significantly accelerate the occurrence of the negative aspects of frost formation vis-à-vis coil heat transfer performance. For this and other reasons, the study presented in this paper focuses on coil frosting and defrosting issues at low temperature with the hope of developing tools and protocols that help refrigeration-system designers and freezer operators improve the performance of freezer coils that are particularly prone to the frosting problem.

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