Theoretical and experimental study of the ammonia water absorption refrigeration cycle with side reboiling and side condensing

Abstract

In the conventional ammonia-water absorption refrigeration cycle, the rectification heat is usually dissipated to the surrounding environment, and the temperature of the weak solution flows at the bottom of the distillation column is normally high. This paper presents an improved cycle implemented with side reboiling by utilizing the heat content of the weak solution, and side condensing by recovering the rectification heat based on the single-effect cycle. The effect of feed thermal conditions and split ratio on the thermal performance of the improved cycle has been explored. The effectiveness of the improved cycle with respect to the single-effect cycle under different operating conditions has been examined. A more conservative effectiveness is selected in this work. The theoretical study demonstrates that the thermal performance of the improved cycle can be as high as 15% more than that of the single-effect cycle, and the improved cycle is more efficient when the heating source temperature or temperature lift is higher. A prototype is developed and tested for experimental verification. The experimental effectiveness ranges from 1.9% to 4.4% based on the test results. The relationship between system performance and temperature lift shows a close tendency with the theoretical results.