Eutectic mixtures of ionic liquids in absorption chillers

Abstract

This invention relates to using a eutectic mixture of two ionic liquids, as an absorbent material in an absorption chiller. The invention provides an absorption chiller comprising a mixture of a refrigerant and an absorbent, and the absorbent is a eutectic mixture of two ionic liquids.

What is claimed is: 
     
         1 . An absorption chiller comprising a mixture of a refrigerant and an absorbent, and the absorbent is a eutectic mixture of two ionic liquids, wherein the two ionic liquids have a concentration ratio at the eutectic point of the eutectic mixture. 
     
     
         2 . The absorption chiller of  claim 1 , wherein the refrigerant is water or ethanol. 
     
     
         3 . The absorption chiller of  claim 1 , wherein the absorbent has a melting point of 290 K or less. 
     
     
         4 . The absorption chiller of  claim 1 , wherein the mixture of the refrigerant and the absorbent has a viscosity lower than 15 centistokes. 
     
     
         5 . The absorption chiller of  claim 1 , wherein the two ionic liquids have enthalpies of fusion within 20 kJ/mol. 
     
     
         6 . The absorption chiller of  claim 1 , wherein the two ionic liquids have melting points within 50K. 
     
     
         7 . The absorption chiller of  claim 1 , wherein the two ionic liquids have the same cation. 
     
     
         8 . The absorption chiller of  claim 7 , wherein the cation is imidazolium or guanidinium. 
     
     
         9 . The absorption chiller of  claim 8 , wherein the two ionic liquids are hexamethylguanidinium acetate and hexamethylguanidinium dicyanamide. 
     
     
         10 . The absorption chiller of  claim 1 , wherein the two ionic liquids have the same anion. 
     
     
         11 . The absorption chiller of  claim 10 , wherein the anion is bromide, chloride, acetate, or dimethylphosphate.