Combination Ovens for Food Service

Lab evaluation of combination ovens using ASTM standard test methods. Purpose of the study is to develop a database of energy performance metrics that can be used to develop and enhance work papers.

A combination oven (or combi-steamer) is a professional cooking appliance that combines the functionality of a convection oven and a steam cooker. That is, it can produce dry heat, moist heat or a combination of the two at various temperatures. In addition to baking and roasting, a combination oven can also steam, blanch, poach and re-thermalize food products. This is especially useful in large kitchens where foods are prepared in very high volumes such as large quantities of bacon, eggs, sausages, French toast, etc. Foods can be cooked in a combination oven mode using forced hot-dry air only; steam (hotmoist air) only; or a combination that uses hot air and steam. The programmability of the combination oven allows the food to be cooked partially in one mode until a certain temperature and then switch to a different mode to finish cooking. For example, a turkey can be cooked in combi mode for few hours and then switched to convection mode to finish up. This project assesses the energy efficiency level of the Rational Model Self Cooking Center (SCC) 102-E (Rational) electric combination oven and seeks to determine an appliance baseline and a minimum energy efficiency level necessary to qualify for the food service qualifying product list. During this project the Rational oven, a full-size commercial electric combination oven with a capacity of ten pans, was examined for various performance metrics. A test procedure was conducted in order to characterize the Rational combination oven's energy input rate, preheat energy and time, idle energy rate, cooking energy efficiency, cooking energy rate and production capacity according to the American Society for Testing and Materials F2861- 10 Standard Test Method for Performance of Combination Ovens. Preheat energy and time; and idle energy rate were evaluated for convection, steam and combination modes. Testing was performed at the Southern California Edison Foodservice Technology Center (FTC) in Irwindale, CA. Cook time, oven temperature, oven power input, and the weight and temperature of the test food were carefully measured. The test foods used during the procedure were red and russet potatoes. The test data provides key information to help determine the operational costs and the percentage of total kitchen productivity a single appliance can deliver.