Numerical and experimental methodology to measure the thermal efficiency of pots on electrical stoves

摘要

In this paper, we present a methodology for calculating the thermal efficiency of a pot on an electric stove using numerical simulations in ANSYS FLUENT~®. The system domain was divided into three subsystems: electrical resistors, the air volume inside the resistors, and the pot. It was determined that the heat transfer to the pot was mainly caused by conduction between the heating element and the pot surface, representing 85.7% of the total energy going into the system. Heat transfer by convection and radiation represented 13% and 1.3% of the total incoming energy, respectively. A method to set the initial value of the contact resistance between the electrical resistance and the pot based on experimental tests is also presented. This initial contact resistance value is a key parameter for the correct simulation of the system. The numerical simulations and experimental tests corresponded well with one another, with a difference of no more than 15% for all geometries analyzed. Finally, a substantial stove improvement is proposed. The enhancement consists of the suppression of the circulating currents that are formed inside the stove by adding an insulating material. With this improvement the heat losses to the surroundings were reduced from 15.19% to 6.64%. And therefore, a potential reduction of the cost of living is possible in the main urban centers of Colombia.