This article aims to enhance the efficiency of Diffusion Absorption Refrigeration (DAR) systems which operate at low efficiency. This study experimentally investigates the effect of passive heat transfer enhancement by using various nanofluids as working fluids including ammonia/water couple with different rates of magnesium oxide aluminate spinel (MgOAl2O3) particles. The tests have been carried at the same ambient conditions to obtain reliable results. Additionally, nanofluid has been prepared and tested in two different particle concentration (1% and 2%). Adding nanoparticles to the base fluid (25% ammonia/water) can make an important positive effect in increasing heat transfer by extending surface area and heat capacity of the fluid. Experimental results showed that using nanofluid as working fluid in DAR system results in faster evaporation which decreases operation time and increases heat transfer in generator. Moreover, the DAR system containing 2% concentration of nanofluid solution led to a 37.4% increase in performance coefficient (COP) and a 44.2% increase in exergetic performance coefficient (ECOP) compared to the DAR system without nano particles.