Experimental investigation on the effect of TiO2 nanoparticles on the performance of NH3 – H2O - LiBr absorption refrigeration system

The newly NH 3 – H 2 O – LiBr working fluid can decrease the power wasted in the generator, thus improves the COP of the ammonia absorption refrigeration system. But the applying of NH 3 – H 2 O – LiBr working fluid decreases the ammonia absorption efficiency, so the COP of the system is still unsatisfactory. To further enhance the COP of the NH 3 – H 2 O - LiBr absorption refrigeration system, TiO 2 nanoparticles are added to the NH 3 – H 2 O - LiBr working fluid in this study. And the effects of TiO 2 nanoparticles concentration on the performances of the generator, absorber, evaporator, condenser, and solution heat exchanger are tested in an ARS experimental system. The experimental results indicate that the addition of TiO 2 nanoparticles increases the P g , P e , P a , and P c , meaning that the value of ammonia produced in the generator increases. Therefore, the COP and iCOP of the system are improved by adding TiO 2 nanoparticles, and the COP is maximum improved by 18.96% compared with the ammonia-water absorption refrigeration system. When the x TiO2 is increased from 0.3% to 0.5%, the increase rate of the COP decreases because the newly added nanoparticles do not disperse well. So 0.3% is a better choice for the TiO 2 nanoparticles concentration when comprehensively considering the dispersion stability of nanoparticles and the COP.