Innovating thermochemical energy storage: thermal performance enhancement of cascade reactor with rotating water spray

Thermochemical energy storage (TCES) presents a promising solution for improving energy efficiency in buildings by capturing and reusing low-grade heat from solar energy, industrial waste heat, or off-peak electricity. However, existing TCES reactor designs often suffer from high pressure drop, limited heat and mass transfer, and high auxiliary energy use, limiting their practicality in building applications. This study enhances TCES system performance by optimizing reactor structures and humidification methods. A cascade reactor structure is proposed, integrating layered zeolite 13X configurations: particles & honeycomb, honeycomb & honeycomb, and hollow column & honeycomb. These designs promote airflow by increasing void fraction, reducing pressure drop and improving heat and mass transfer. Comparing to the conventional humidification using an ultrasonic humidifier, a rotating water spray humidification system is introduced. A total of 108 experimental tests were conducted, evaluating charging and discharging cycles across three reactor types, three airflow rates, and two humidification methods. Results show that the honeycomb & honeycomb reactor reduces pressure drop by 53.92 %, while the particles & honeycomb reactor with water spray achieves a thermal efficiency of 38 %, being the highest in the recent literature with the same adsorption material. The spray method reduces electricity consumption by 79.17 %. The findings contribute to the development of energy-efficient, low-emission heating systems with TCES for buildings.