Rethermalizers for Foodservice Applications

Rethermalization ovens or “Retherms” are heated cabinets used to reheat previously prepared, stored and chilled food product to serving temperature all while retaining the food product’s color, flavor, texture and nutrients. Retherms are popular among schools, hospitals, prisons, and other institutional facilities that use centralized kitchens to mass produce food product that can be reheated for fast and easy service. Retherms have low emissions and, therefore, do not require a ventilation hood. As a result, retherms are increasingly popular due to lower upfront capital investment compared to a full commercial cook line. The main cavity is accessed by doors leading to a heated cabinet. They can be factory configured to hold pans or baskets depending on customer preference. This project assesses the energy efficiency level of five retherm ovens and seeks to determine an appliance baseline and a minimum energy efficiency level necessary to qualify for the food service qualifying product list. The food service qualifying product list identifies the most efficient commercial kitchen appliances within a specific appliance category. The qualifying appliances are eligible to receive incentives for their use.

Rethermalization ovens or “Retherms” are heated cabinets used to reheat previously prepared, stored and chilled food product to serving temperature all while retaining the food product’s color, flavor, texture and nutrients1. Retherms are popular among schools, hospitals, prisons, and other institutional facilities that use centralized kitchens to mass produce food product that can be reheated for fast and easy service. Retherms have low emissions and, therefore, do not require a ventilation hood. As a result, retherms are increasingly popular due to lower upfront capital investment compared to a full commercial cook line. The main cavity is accessed by doors leading to a heated cabinet. They can be factory configured to hold pans or baskets depending on customer preference. This project assesses the energy efficiency level of five retherm ovens and seeks to determine an appliance baseline and a minimum energy efficiency level necessary to qualify for the food service qualifying product list. The food service qualifying product list identifies the most efficient commercial kitchen appliances within a specific appliance category. The qualifying appliances are eligible to receive incentives for their use. Southern California Edison (SCE) examined each retherm for various performance metrics. The test procedure measured the retherm’s cooking energy rate, preheat energy consumption, energy consumption, and water consumption according to the American Society for Testing and Materials (ASTM) F 3216 Standard Test Methods for Performance of Retherm Ovens. Southern California Edison’s Foodservice Technology Center (FTC) in Irwindale, CA performed the testing. Cook time, cavity temperature, cavity humidity, retherm power input, and the weight and temperature of the test food were carefully measured. The test food used in this study were a four-pound (lb) bags of mashed potatoes. From the extensive measurements collected, oven efficiency and numerous heat rate and uniformity factors were calculated. The test data provides key information to help determine the operational costs and the percentage of total kitchen productivity a single appliance can deliver.