Absorption heat pump with sorbent comprising a lithium salt and an organic salt with the same anion

Abstract

An absorption heat pump with a sorbent comprising a lithium salt and at least one organic salt with an organic cation Q + , the lithium salt and organic salt having the same anion, the anion having a molar mass of not more than 200 g/mol and not being halide, and the organic cation Q + having a molar mass of not more than 200 g/mol, exhibits an improved degassing range of the working medium composed of refrigerant and sorbent.

1 - 16 . (canceled) 
     
     
         17 . An absorption heat pump comprising an absorber, a desorber, a condenser, an evaporator, a volatile refrigerant and a sorption medium, wherein the sorption medium comprises a lithium salt and at least one organic salt having an organic cation Q + , wherein:
 a) said lithium salt and said organic salt have the same anion;   b) said anion has a molar mass of not more than 200 g/mol and is not a halide; and   c) said organic cation Q +  has a molar mass of not more than 200 g/mol.   
     
     
         18 . The absorption heat pump of  claim 17 , wherein the sorption medium contains the lithium salt and the organic salt in a molar ratio at which the mixture of lithium salt and organic salt has a melting point lower than the melting points of the lithium salt and the organic salt. 
     
     
         19 . The absorption heat pump of  claim 18 , wherein the sorption medium contains the lithium salt and the organic salt in a molar ratio which deviates by not more than 25% from the molar ratio of a eutectic mixture of lithium salt and organic salt. 
     
     
         20 . The absorption heat pump of  claim 17 , wherein the proportion of lithium salt and organic salt in the sorption medium is more than 50% by weight. 
     
     
         21 . The absorption heat pump of  claim 17 , wherein the refrigerant is selected from the group consisting of water, methanol, ethanol, 2-propanol, trifluoroethanol, sulphur dioxide, carbon dioxide and ammonia. 
     
     
         22 . The absorption heat pump of  claim 21 , wherein the refrigerant is water. 
     
     
         23 . The absorption heat pump of  claim 17 , wherein a solution of the lithium salt in the refrigerant which is saturated at 35° C. has a higher vapour pressure than a mixture of the organic salt and the refrigerant having the same proportion by weight of refrigerant. 
     
     
         24 . The absorption heat pump of  claim 17 , wherein the organic cation Q +  is selected from the group consisting of 1,3-dialkylimidazolium ions, 1,3-dialkylimidazolinium ions, N-alkylpyridinium ions, N,N-dialkylpyrrolidinium ions and ammonium ions having the structure R 1 R 2 R 3 R 4 N + , where R 1 , R 2  and R 3  are each, independently of one another, hydrogen, alkyl or hydroxyethyl and R 4  is an alkyl radical. 
     
     
         25 . The absorption heat pump of  claim 17 , wherein the anion is selected from the group consisting of nitrate, formate, acetate, cyanate, sulphate, methylsulphate, carbonate, oxalate, succinate, methylphosphate, dimethylphosphate, hydrogenphosphate and dihydrogenphosphate. 
     
     
         26 . The absorption heat pump of  claim 17 , wherein the anion has a pK b  of more than 5. 
     
     
         27 . The absorption heat pump of  claim 17 , wherein the anion carries a single negative charge. 
     
     
         28 . The absorption heat pump of  claim 27 , wherein the anion is the anion of a monovalent acid. 
     
     
         29 . The absorption heat pump of  claim 17 , wherein said absorption heat pump is operated as an absorption refrigeration machine and heat is taken up in the evaporator from a medium to be cooled. 
     
     
         30 . The absorption heat pump of  claim 17 , wherein said absorption heat pump has a two-stage construction. 
     
     
         31 . The absorption heat pump of  claim 17 , wherein a vapour phase containing refrigerant and a liquid phase containing sorption medium are separated from one another by a semipermeable membrane in the absorber and/or desorber and the semipermeable membrane is permeable to the refrigerant and impermeable to the sorption medium. 
     
     
         32 . The absorption heat pump of  claim 17 , wherein at least one of the components selected from the group consisting of absorber, desorber, condenser and evaporator has a wall surface made of a polymeric material selected from the group consisting of polyamides, polyimides and polyether ether ketone via which wall surface exchanges heat with the surroundings.