The use of re-generable energy sources is an imperative issue of our times. The solar energy can be used for air-conditioning too, provided that absorption thermal machines are implemented into the air-conditioning system. The paper presents a comparative thermodynamic analysis of two single-stage absorption refrigeration machines: the first one working with the NH3-H2O solution, and the second one working with the BrLi-H2O solution. The functioning parameters for the two absorption refrigeration machines are imposed, by the temperature of the heating fluid feeding the vapour generator - on the one hand, and by the cooling temperature level in the evaporator (demanded by the air-conditioning system) - on the other hand.