The effect of ejector on the performance of diffusion absorption refrigeration systems: An experimental study

In this study, an experimental analysis on performance improvement of a diffusion absorption refrigeration system (DARS) was conducted. For the experiment, three DARS cycles were set up and investigated. (i) In the first cycle (DARS-1), representing the most commonly employed model in the industry, the condensate is sub-cooled prior to the evaporator entrance by the coupled evaporator/gas heat exchanger in a similar manner with the refrigeration systems manufactured by Electrolux Sweden [1]. (ii) In the second cycle (DARS-2), the condensate is not sub-cooled prior to the evaporator entrance and the gas heat exchanger is separated from the evaporator as proposed by Zohar et al. [2]. (iii) In the third cycle (DARS-1WE), the novel system being proposed in this study, differing from DARS-1 in certain aspects is used, in which an ejector was installed to the absorber inlet of DARS-1. The weak solution coming from the generator is separated into two parts with equal flows and then one of the parts is connected to the mixing tube of ejector and the other inlet is connected to the absorber. Experimental results show that the DARS-1WE cycle demonstrates a higher performance compared to DARS-1 and DARS-2 cycles. In addition, internal temperature of the cooling area in DARS-1WE decreased to 3.2 °C as well. In other words, the duration of attaining the predetermined cooling area temperature decreased even further in DARS-1WE. Consequently, the reduction of energy consumption for relatively low temperatures (6 °C) of the cooling area is in the order of 40%. The corresponding level of energy saving falls down to 20% for higher temperatures (10 °C). ► Ejectors are used in the cooling system creates a new pressure and increases the rate of refrigerant circulation. ► Cooled faster than the desired temperature is reached. This also reduces the cost of energy. ► Diffusion ejector absorption refrigeration system, a gain can be achieved with the use of the maximum rate of 20%.