In hot regions like the southern Algeria, a huge amount of energy is used for cooling. This study presents a methodology of exergy and energy analysis for ammonia-water and ammonia-lithium nitrate absorption cooling coupled to a double glazed flat plate collector. The thermal energy is stored in an insulated thermal storage tank. To compare total exergy loss and improve the coefficient of performance and exegetic efficiency for both solutions, the effects of heat exchanger efficiency, storage temperature, absorber, and condenser and evaporator temperature have been discussed in this study. Thermodynamic models have been developed using the first and second laws of thermodynamics. These models are employed in a computer program using FORTRAN to perform the calculations. Results indicate that ammonia-lithium nitrate cycles gives or even better performance than the ammonia-water cycle, Therefore, it’s suitable alternative to the ammonia-water cycle. Exergy analysis shows also that the total exergy loss in the system depends strongly on the working temperatures.