Numerical modeling and performance analysis of an open sorption energy storage system based on zeolite/water in building heating

The performance of sorption energy storage is influenced by operating conditions. Based on a zeolite/water reactor, a mathematical model of an open sorption energy storage system is established and the effects of several operating parameters are studied. Increasing the temperature in the charging process enhances mass transfer. Increasing the air mass flow rate increases the heat transfer coefficient but decreases the temperature and reduces the mass transfer coefficient. A higher mass transfer coefficient is beneficial for energy storage. Inlet air humidity has little effect on the heat transfer coefficient but increases the mass transfer coefficient, thereby promoting energy release. Meanwhile, reactor inlet air temperature is the main factor affecting the charging process and the initial water uptake is an important parameter in the discharge process. Higher inlet moisture and lower initial water uptake can achieve better thermal performance. An 80 kg/h air mass flow rate and 6 of collector cascade numbers are recommended, which can achieve 5.84 kWh of the cumulative charged energy and 48.2 % charging efficiency. Moreover, the long-term stable heat supply with a discharging efficiency of 49.0 % can be achieved at air 75 kg/h of mass flow rate and 8 g/kg of inlet air moisture.