A tube-in-tube heat exchanger utilizes a selectively permeable tube having a selective permeable layer to allow the refrigerant to transfer into an ionic liquid to generate heating or cooling. The ionic liquid then provides heating or cooling to a heat transfer fluid through a non-permeable layer or tube. The system may be configured as a shell and tube design, with the third fluid free to flow on the outside of the shell, or as a shell and tube-in-tube, with a central tube containing a first liquid, a second tube containing a second liquid, and an outer shell containing the third liquid. The selectively permeable tube may include an anion or cation selectively permeable layer and this layer may be supported by a support layer or tube.