NOVELTY - A heat transfer system (100) comprises a working fluid containing a polar solvent that primarily acts as a condensable refrigerant and hydrogen that primarily acts as an electrochemically-active component; and an electrochemical compressor (110) including an inlet fluidly coupled to an evaporator to receive the working fluid, an outlet fluidly coupled to a condenser, and electrochemical cell electrically connected to each other through a power supply (106), where each electrochemical cell comprises a gas pervious anode (120), a gas pervious cathode (122), and an electrolytic membrane.    USE - As a heat transfer system (claimed) such as refrigeration cycles and heat pumps which removes heat from a heat source or reservoir at low temperature and rejects the heat to a heat sink or reservoir at high temperature; and in electric cars.    ADVANTAGE - The heat transfer system utilizes working fluid that has good thermodynamic properties, is noncorrosive, stable, and safe; easily modulate from low capacity (i.e. low current density at a specific voltage) to a high capacity; and operates at high capacities thus actually becoming more efficient at lower utilizations.    DETAILED DESCRIPTION - A heat transfer system (100) comprises a working fluid containing a polar solvent that primarily acts as a condensable refrigerant and hydrogen that primarily acts as an electrochemically-active component; an electrochemical compressor (110) including an inlet fluidly coupled to an evaporator to receive the working fluid, an outlet fluidly coupled to a condenser, and at least one electrochemical cell electrically connected to each other through a power supply (106), where each electrochemical cell comprises a gas pervious anode (120), a gas pervious cathode (122), and an electrolytic membrane disposed between and in intimate electrical contact with the cathode and the anode to pass the working fluid; a condenser that transfers heat from a first heat reservoir to the working fluid; an evaporator that transfers heat from the working fluid to a second heat reservoir; and an expansion valve between the condenser and the evaporator that reduces pressure of the working fluid. The polar solvent comprises methanol. The working fluid comprises water. An INDEPENDENT CLAIM is included for transferring heat using a working fluid that is circulated through and contained within a closed loop, involving increasing a pressure of at least hydrogen of the working fluid by oxidizing the hydrogen at an anode, conducting the oxidized hydrogen across an electrolyte, and reducing the hydrogen at a cathode; and propelling a mixture of a polar solvent and water with the hydrogen across the anode, electrolyte, and cathode.    DESCRIPTION OF DRAWING(S) - The figure shows block diagram of a self-contained heat transfer system.    Heat transfer system (100)    Power supply (106)    Electrochemical compressor (110)    Anode (120)    Cathode (122)