15 May 2023

Presentation No 349 – Ionic liquid absorption system for dehumidification and IAQ enhancement in built environment – 14th IEA Heat Pump Conference, Chicago, USA

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. This limitation often leads to implementation of reheat to bring the air to a desired supply
temperature to maintain comfort and indoor air quality (IAQ). Liquid desiccant absorption systems have been
considered to handle the latent load such that need for reheat is eliminated. However, a low energy efficiency,
high cost, and operational and maintenance complexities have prevented such systems from becoming a
mainstream product. Here, we report progress on development of ionic liquid desiccant dehumidification
systems with a membrane-based absorber that promise to overcome shortcomings of the existing desiccant
dehumidification systems. We compare performance of the system operating with adiabatic and internally
cooled membrane-based absorbers. The studies are conducted at Integrated Seasonal Moisture Removal
Efficiency (ISMRE) inlet air conditions. Effect of dew point temperature on system capacity and coefficient
of performance (COP) is studied. A maximum COP of 0.82 is reached, showing promise in terms of energy
efficiency. The studies also suggest that further enhancement in dehumidification level is required to meet the
needs of HVAC systems.