Effect of the insulation on the efficiency of domestic electric ovens

GOÑI, SANDRO MAURICIO; SALVADORI, VIVIANA O.

Sitges, España

Conferencia; 31st Annual Conference of European Federation of Food Science and Technology; 2017

EFFoST

The aim of this work was to assess the energetic efficiency of cost-effective electric ovens, which at the moment do not have any energy efficiency label. In general, this kind of ovens does not have any insulation, and then the energy losses through their walls are considerable. In this work a domestic electric oven was employed, 1.8 kW power, 50 L capacity. The oven was tested at 150, 200 and 250 ºC, first in its original configuration and in second place, covering their walls with an insulating material: fiberglass about 1 cm thickness was incorporated in the floor, the roof, the back wall, and a lateral wall; the glass door was not modified, and the other lateral wall was maintained unaltered to not interfere with the temperature control system. Once the internal temperature of the oven, measured using thermocouple, was stabilized, the ratio between the heating time (electric resistances turned on) to the total time was used as an efficiency measure.The insulation allowed improving the energy efficiency in two different ways, since the electric power consumption diminished and the average temperature of the oven chamber increased. These changes were slight, but they could be improved using a better insulation material (lower conductivity or higher thickness), changing the temperature control system location and the door features. The temperature of the oven roof close to the door side and the back wall side were slightly modified using the insulation, because the oven chamber is connected with the outer case with the same metallic layer, which favours quick heat flux by conduction through it, with the subsequent energy loss to the ambient. Then, for a smart oven design, the connection of the structural elements must be the first feature to consider.