Horizontal thermal energy storage system for Moroccan steel and iron industry waste heat recovery: Numerical and economic study

Implementing thermal energy storage for the recovery of massive and intermittent waste heat represents crucial milestone for energy-intensive sectors such as iron and steel industry. However, the constraints related to current available sensible heat storage systems remain a barrier for their deployment. This work aims at examining high temperature horizontal thermal energy storage concept filled with channels of byproduct issued from the same industry as filler material and air as heat transfer fluid. The storage tank design is investigated as promising cost-efficient configuration from numerical, technical, and economic viewpoints. The focus is to assess the thermal behavior as well as the economic savings of this emergent concept addressed for the recovery of waste heat in Moroccan iron and steel industry. Numerical findings demonstrate that thermal performances, i.e., discharge and cycle efficiencies as well as charging and discharging times remain stable after six cycles of charge/discharge but the challenge is related to discharge efficiency (approximately 30%). Consequently, more efforts are required to upgrade thermal performance for such configuration. However, outcomes also proved the profitability of this emergent concept for energy, electricity, fuel, and gas emission savings. The economic results show that implementing horizontal thermal energy storage tank has a lot of promise, with cost savings of up to 900000 dollars per year and a payback period of less than one year.