Parametric analysis of lithium battery cooling in hybrid desalination systems

• Humidification-Dehumidification Desalination is integrated to battery cooling. • Experiment of the whole system and simulation of the humidifier are carried out. • Applying four 12 V and 14.5 Ah batteries enabled 4.441 × 10 −5 kg/s desalination rate. • Increasing the evaporation area can offset poor convective heat transfer. • Low-cost thermal paste with 5 W/(m·K) suffices for both desalination and cooling. Desalination is crucial for addressing freshwater scarcity, especially in decentralized areas where small-scale solutions like humidification-dehumidification (HDH) are preferred. However, HDH relies on low-grade heat, with large irreversible losses if using active sources like solar or combustion. This study integrates lithium-ion battery waste heat into HDH desalination to achieve both thermal management and freshwater production. Battery waste heat is transferred to an evaporative zone where seawater evaporates, absorbing latent heat to cool the batteries while generating humid air that is then condensed into freshwater. Experiments and a multiphysics model analyzed impacts of flow rate, evaporative zone geometry, thermal conductivity, and heat sink structure. Results show 50 % evaporative zone yields 4.441 × 10 −5 kg/s evaporation while keeping average battery temperature below 50 °C. Concentrating heat in the preheating section can enhance the humidification potential of air but insufficient convective heat transfer efficiency will reduce overall system performance. This negative effect can be mitigated by increasing the effective evaporation area, such as expanding the evaporative zone in off-grid battery systems to maintain stable cooling and freshwater output. Paste layer thermal conductivity minimally affects production, allowing the use of low-cost 5 W/(m·K) materials to reduce real-world application costs.