A systematic approach to the energy efficient design of single effect solid-gas Thermochemical Refrigerators (TR) using the appropriate choice of salt materials is proposed. The approach includes three major steps. The first one, the targeting step, is applied to the ideal thermochemical process. It allows identification of the energy performance targets (the ideal Coefficient of Performance, COPi) as a function of external temperature conditions and the internal distribution of energy Rows within a thermochemical system. Targets can be set without actually having to carry out the design of the system. This step characterizes only the thermodynamic feasibility of an ideal thermochemical process. A new graphical technique, a modified Carnot factor vs. heat diagram, is applied to determine the targets. In the second step, in order to achieve the targeted COPi value, the design options of ideal thermochemical systems using different salt materials are generated. The physicochemical feasibility of the options is ensured in this step on the Clausius-Clapeyron diagram. Finally, in the third step, the assessment of the thermodynamic irreversibilities produced within real thermochemical processes using the same materials as the ideal ones allows evaluation of the real COP values. This step is the traditional energy and exergy analysis that ensures the thermodynamic feasibility of the real thermochemical systems.