Review on frosting, defrosting and frost management techniques in industrial food freezers

This paper reviews the results of frosting, defrosting and frost management research that have been reported over the past fifty years. The literature can be split into three categories: frost formation and properties, frost effect and frost management techniques, and those for different geometries and under different conditions. The aim is to provide an overview of the studies made over recent years that have targeted frost management, so researchers, manufacturers, designers and any concerned party can quickly obtain essential and sufficient information about the frosting phenomenon, allowing them to develop and complete ongoing studies. Emphasis is placed on analyzing available experimental, theoretical and numerical studies in industrial food freezing conditions. The specificities, constraints and challenges of industrial freezing are discussed in each section. Under industrial freezing conditions, several sources of humidity are involved and a third mechanism of frost formation in the air, may occur, resulting in less dense and more insulating frost. Numerical modeling has shown promising results in frosting/defrosting but other major parameters still need to be modeled in order to represent the real behavior of industrial systems. Evaporator-fan coupling must be taken into account as well as the need for a dynamic system approach. Many frost formation retardation and defrosting strategies may not provide the same effectiveness in these conditions compared to others. Several preventive, technical and research solutions have yet to be found. In this review, the gaps existing in research on frost in industrial food freezing conditions are identified, and recommendations are provided.