Numerical Prediction of Energy Consumption and Optimization of Thermal Insulation of an Electrically-Heated Water Heater

In the electrically-heated water heater, several major energy transfer processes are involved: the heating process of the water, natural convection of the water and heat dissipation of the water through the insulation layer. In the present paper, multiscale numerical simulation was conducted to simulate the heat transfer and fluid flow in the water heater: LBM was adopted to predict the thermal conductivity of the porous media insulation layer which served as input data for Fluent in ANSYS Fluent. In addition, User Defined Function was developed to control the intermittent heating to the water. The energy consumption coefficients obtained by the simulations fit well with the experimental results. Fluid flow characteristics, temperature profile and heat dissipation distribution were also obtained to guide the optimization of the thermal insulation layer.