Ionic Liquid-Based Absorption Cooling System

Technology #15465

Improves the Coefficient of Performance by Using Solutions that Exhibit Lower Critical Solution Temperature Behavior

This cooling system utilizes ionic liquids to improve the coefficient of performance in an absorption refrigeration system. Cooling systems play a major role in heating, ventilating, and air conditioning (HVAC) equipment. The coefficient of performance is the ratio of heating or cooling provided to electrical energy consumed. The coefficient of performance of absorption systems has not seen a significant improvement since their introduction in the 18th century. Available absorption refrigeration systems function by evaporating the refrigerant in the desorber, which requires a large amount of energy. Researchers at the University of Florida have developed an absorption cooling system that increases the coefficient of performance by minimizing the amount of energy required during the desorption process. This is possible by using an ionic liquid and an alcohol, as the absorbent, and refrigerant that phase separates with little heating.


Increases the coefficient of performance in residential or commercial air conditioning systems


  • Increases efficiency of each cycle, reducing required cost for operation
  • Lessens amount of heating required in separator, lowering energy requirement
  • Decreases complexity of refrigeration cycles, allowing for more compact systems


This cooling system offers competitive advantages over existing absorption refrigeration systems. The refrigerant-absorbent pairs were chosen for their ability to become immiscible with minimal heating. This immiscibility is through using an ionic liquid. When a mixture of fluid and ionic liquid is above the Lower Critical Solution Temperature (LCST), the two fluids are immiscible. Researchers at the University of Florida have developed a refrigeration cycle that facilitates the removal of a condenser. The refrigeration cycle translates to a higher coefficient of performance for the cycle.