Wave analysis method for air humidity assisted sorption thermal battery: A new perspective

Sorption thermal battery has attracted burgeoning attention which is considered as a promising method to reduce energy consumption for space heating. Sorption “reaction wave” model could be used to find the criteria for stable output. However, mechanism of sorption process evolution in reactor is still unclear since the method cannot derive more reaction details. The paper initially proposes a comprehensive wave analysis method which could bring more insights of sorption thermal battery from a heat and mass transfer perspective. The wave parameters are analysed and orthogonal experiments are then carried out. Results indicate that solid sorbents with type I and V isotherms have the advantage of stable heat supply. Air velocity and inlet relative humidity have the most significant influence on the output parameters. Besides, response surface methodology is adopted to evaluate the critical parameters, e.g., relative humidity, flow rate, temperature of inlet air. The optimal system energy storage density could reach 191.7 kWh·m−3 when sorption reactor length is 0.178 m and the relative humidity is 70 % using zeolite 13X as sorbents. Therefore, the proposed wave analysis method is expected to become a potential solution which would guide sorbent selection and reactor design for sorption thermal battery.