The objectives of this paper are to examine the effect of nano-particles on the pool type absorption heat transfer enhancement and to find the optimal conditions to design a highly effective compact absorber for ammonia/water absorption system. The effect of Al₂O₃ nano-particles and carbon nanotube(CNT) on the absorption performance is studied experimentally. The experimental ranges of the key parameters are 20% of ammonia concentration, 0~0.08 vol% (volume fraction) of CNT particles, and 0~0.06 vol% of Al₂O₃ nano-particles. For the ammonia/water nanofluids, the heat transfer rate and absorption rate with 0.02 vol% Al2O3 nano-particles were found to be 29% and 18% higher than those without nano-particles, respectively. It is recommended that the concentration of 0.02 vol% of Al₂O₃ nano-particles be the best candidate for ammonia/water absorption performance enhancement.