Detailed thermodynamic analysis of the boiler-bubble pump region of a diffusion absorption refrigeration system: experimental and numerical study

Abstract

Global warming, inadequate natural sources and an energy crisis are significant concerns in this century. In this context, it has become important to use efficient energy technologies and reduce energy consumption in the cooling industry. In recent years, Diffusion Absorption Refrigeration (DAR) systems have been widely studied as good alternatives to vapor compression cooling systems. In this article, the heat exchanger part located in the boiler-bubble pump region of the DAR system was numerically modeled to determine its behavior. In addition to modeling, five different working fluids were utilized in the DAR system experimentally. The first test was performed utilizing 25% NH3-H2O by mass without nanoparticles. The other four tests were repeated by adding 1% and 2% (by weight) zinc oxide (ZnO) and graphene oxide (GO) nanoparticles into 25% NH3-H2O solution, respectively. The numerically obtained results showed no significant increase in the use of ZnO nanoparticles by 1% or 2%. It was seen that GO nanoparticles made a more meaningful difference in the heat transfer increment than the ZnO nanoparticles. Furthermore, experimental results showed that the utilization of nanoparticles in a 25% NH3-H2O solution assists in disappearing refrigerant. Generally, it was determined that adding nanoparticles to the base fluid eliminates the effects of temperature changes in the system.