Experimental study on the influence of adding TiO₂ nanoparticles on practical ammonia-water absorption refrigeration system-the generation and rectification processes

The efficiency of the rectification process determines whether the ammonia-water absorption refrigeration system (AARS) can operate efficiently. Therefore, this paper experimentally investigates the effects of added TiO₂ nanoparticles on the generation and rectification processes. The stable TiO₂ ammonia-water nanofluids are prepared through an own preparation process and are circulated in the solution loop of the AARS. During the experiments, the addition of TiO₂ nanoparticles is adjusted to explore the relationship between the generation and rectification processes and the amount of nanoparticles added. The reliable experimental data show that under the same working conditions, the circulation factor can be effectively reduced by up to 8% and the deflation ratio can be effectively increased by up to 10% on account of the growth of heat and mass transfer after adding the TiO₂ nanoparticles, which results in a maximum increase of around 14% in system’ COP. According to later research, the improvement of rectification efficiency can also be attributed to the hydrophilicity of TiO₂ nanoparticles. Overall, this paper provides reliable and practical experimental data and a new direction for improving the generation and rectification processes in AARS to facilitate the application of the system.