An electrochemical heat pump consisting of two electrochemical cells, operating at different temperatures (T2 > T,), one as a galvanic cell at T, and the other as an electrolysis cell at T,, is proposed. In the case that the reaction at T, runs in the direction of negative entropy change and the reverse reaction occurs at T,, the system operates as a heat pump.
A thermodynamic description of the system is given, from which expressions for the total voltage, the reversible heat exchange, the electrical work done on the system, the total heat output and the efficiency are derived.
The heat pump is simulated with a computer programme using some examples of fast electrochemical reactions. Calculations are made with concentration conditions such that a semi-continuous cyclic operation is possible by changing the temperatures and the reaction directions after each cycle.
The efficiency of the electrochemical heat pump for each reaction system is discussed in terms of the units of heat given off at the high temperature cell per unit of electrical work consumed by the whole system during operation. The values obtained for given galvanostatic operating conditions cover a range from 3.90 to 5.47 kJ,,/kJ,, for the different reactions used in the calculations.