Numerical and experimental study of a solid matrix Electric Thermal Storage unit dedicated to environmentally friendly residential heating system

This paper presents the concept of a sensible heat Electric Thermal Storage (ETS) system dedicated to household central heating. ETS is the technology of converting off-peak electricity into heat and using it in household heating 24 h a day. An ETS system is comprised of electric heating elements which are embedded within a high-density solid matrix. Since the thermal energy is stored in the solid matrix during off-peak hours and is discharged during peak hours, it results in significant savings in the household heating cost. A numerical model is developed to analyze the performance of the ETS unit, the central component of the presented system. The energy conservation equations for the solid matrix and air domains are formulated. Solid matrix is modeled as a porous medium, where radial heat conduction is neglected. The governing system of differential equations with boundary and initial conditions is solved using the Finite Volume Method. The developed model allows determining the air temperature at the outlet of the Electric Thermal Storage unit. Despite the simplified assumptions considered in the numerical model formulation, a good coincidence of the computation results with experimental data is reached. The heating system proposed in the paper meets the air quality requirements imposed by the environmental regulations and is an efficient and environmentally friendly heating systems for residential buildings.