Recent advances in semi-open ionic liquid absorption heat pump for separate sensible and latent cooling
Cooling systems are a necessity of modern civilization that have greatly enhanced our standard of living and enabled the development of large population centers in harsh climates. However, a key shortcoming of the existing prominent cooling system i.e., vapor compression system is the need for overcooling of air to condense its moisture content. Here, we report on recent advancements in absorption-based dehumidification using ionic liquids (ILs), focusing on their integration into a novel semi-open cycle architecture to achieve high energy efficiency in ventilation air treatment. Building on our recent work in ionic liquid design, we demonstrate how tailored ILs with high affinity for water vapor and low regeneration temperatures can significantly enhance moisture removal performance while simplifying system components. In parallel, we introduce a semi-open absorption cycle that eliminates the need for outdoor scavenging air in the regenerator—a longstanding inefficiency in traditional open desiccant systems. Experimental evaluation of this cycle under a range of outdoor conditions reveals marked improvements in thermal efficiency, including a dehumidification coefficient of performance (COP) reaching 0.9 and peak latent cooling capacity at elevated dew points. This architecture substantially reduces sensible heat loss during regeneration, enabling more effective decoupling of latent and sensible loads in the Separate Sensible and Latent Cooling (SSLC) framework. Together, these advancements in IL formulation and cycle design address critical challenges in humidity control and offer scalable, climate-resilient solutions for reducing the energy footprint of building ventilation. The findings reinforce the potential of ionic liquid-based absorption systems to redefine conventional dehumidification strategies and support sustainable indoor environmental management.