In order for the solar absorption air conditioners to become a real alternative to the conventional vapour compression systems their performance has to be improved and their total cost has to be reduced A solar powered absorption cycle is modeled using the Transient System Simulation (TRNSYS) program and Typical Meteorological Year 2 data of Abu Dhabi It uses evacuated tube collectors to drive a 10 kW ammonia water absorption chiller Firstly, the system performance and its total cost are optimized separately using single objective optimization algorithms The design variables considered are the collector slope the collector mass flow rate, the collector area and the storage tank volume The single objective optimization results show that MATLAB global optimization methods agree with the TRNSYS optimizer Secondly, MATLAB is used to solve a multi-objective optimization problem to improve the system's performance and cost, simultaneously The optimum designs are presented using Pareto curve and show the potential improvements of the baseline system (C) 2010 Elsevier Ltd All rights reserved