This paper compares the theoretical performance of the modeling of a solar absorption system for simultaneous cooling and heating operating with water/lithium bromide, and alternative aqueous ternary hydroxide mixtures. Aqueous ternary hydroxide working fluid consists of sodium, potassium and cesium hydroxides in the proportions 40: 36:24 (NaOH:KOH:CsOH). Plots of Carnot coefficients of performance and enthalpy-based coefficients of performance are shown against the evaporator temperature. The results showed that, in general, the system with the hydroxide mixture may operate with higher coefficients of performance than the system with the lithium bromide mixture. Also it was shown that the system with the hydroxide may operate with a higher range of temperatures.