Preliminary research of novel liquid ammonia-water mixture energy storage system

Liquid gas energy storage system has higher energy density than compressed gas energy storage system. Meanwhile, compared to air and carbon dioxide, ammonia-water mixture fluid is easier to be liquefied under low pressure. In this work, ammonia-water mixture is used as working fluid in liquid gas energy storage system, two novel liquid ammonia-water mixture energy storage (LAWES) systems are proposed, the ammonia-water mixture fluid can be liquefied by ambient water under ambient pressure. Energy and exergy performances of LAWES are evaluated and compared, parametric sensitivity analysis is conducted, system performances are optimized by multi-objective particle swarm optimization. The results show that configuration 1# has a better performance, optimal roundtrip efficiency (RTE) and energy density (EVR) of configuration 1# are 66.28 % and 44.88 kWh∙m⁻³, respectively. Meanwhile, >50 % exergy destruction are occupied by thermal energy storage unit (TES) in both configurations. Furthermore, the turbine inlet pressure has a positive effect on RTE and EVR.