Analytical and experimental evaluation of a household refrigerator operating under a diffusion-absorption refrigeration cycle

The diffusion-absorption refrigeration (DAR) cycle has characteristics as the use of three working fluids and a low COP. In this work, an analytical and experimental investigation of a household refrigerator operating under a H20-NH3-H2DAR cycle is performed. A thermodynamic model of the DAR cycle was developed and adjusted based on models available in the literature. An experimental investigation was performed aiming to validate the developed DAR model using operating data collected in a real refrigerator. Subsequently the role of refrigerant rectification in the cycle was investigated and it was found that the temperature at the outlet of the rectifier should not exceed 70 °C. In addition, the importance of the production of liquid refrigerant in the condenser was investigated. It was observed that the COP decreases with the increase in the temperature of the inert gas entering the liquid heat exchanger (LHE). Finally, it was demonstrated that by increasing the amount of inert gas in the evaporator, there is a drop in evaporation temperature and consequently in the system COP.The model proved to be robust in the operational conditions tested experimentally.