This paper can help you modeling the absorption refrigeration cycle:
Computer modeling of a single-stage lithium bromide/water absorption refrigeration unit, Lansing, F. L., AA(Jet Propulsion Lab., California Inst. of Tech., Pasadena)
Is it going to be for HVAC? it is better to use Li-Br. However, you can use EES external library to get the properties. I have it for single and double effect absorption chiller. It is kind of difficult when it comes to chemical exergy for Li-Br.