Transient analysis and techno-economic assessment of thermal energy storage integrated with solar air heater for energy management in drying

The integration of thermal energy storage (TES) system with solar air heater holds an immense potential for optimising the energy management in drying application. In this pioneer research, a transient thermodynamic model of conical shaped rock bed TES has been developed, and the economic analysis of hybrid V-groove double pass solar air heater (SAH)-TES has been studied, offering a unique perspective on the feasibility and economic viability of hybrid SAH-TES for drying application. By considering the time dependent dynamics of energy demand, the model predicts energy stored and released by the system during charging and discharging with a considerable error of 9.9%, as validated with a pilot scale experimental setup. The numerical and experimental results showed that the stored and recovered energy is highly dependent on the inlet temperature and flow rate of air. Notably, the optimised conical shaped TES has the capacity of storing 15.6 kWh of energy during six-hour charging period enabling the recovery of 33% of the stored energy to power the dryer during the discharge period. Moreover, the pressure drop across the TES observed to be 1306.37 Pa/m at 0.050 kg/s, which quantify the power required for fan to overcome such pressure drop to be 4.22 kW Furthermore, the economic assessment showcased remarkable reduction in energy payback period, dropping from 0.7 years to 0.5 years using hybrid SAH-TES dryer compared to SAH dryer. This demonstrates the superior economic value of the hybrid SAH-TES dryer paving the way for the scalability and widespread adoption of low-carbon drying industry.