Effect of salt on the performance of ammonia absorption refrigeration cycle: A simulation study

Abstract

To overcome the drawbacks associated with conventional binary mixtures (NH<inf>3</inf>-H<inf>2</inf>O and H<inf>2</inf>O-LiBr) in the vapor absorption refrigeration system (VARS), salt is added to the NH<inf>3</inf>-H<inf>2</inf>O mixture. The present simulation study analyzes the influence of adding LiBr and LiNO<inf>3</inf> salts within a salt mass fraction range of 0 to 35% on the coefficient of performance (COP) of the NH<inf>3</inf>-H<inf>2</inf>O cycle. The simulations are conducted using Aspen Plus software. Furthermore, the influence of generator temperature on the COP and evaporator capacity of the ternary NH<inf>3</inf>-H<inf>2</inf>O-LiBr and NH<inf>3</inf>-H<inf>2</inf>O-LiNO<inf>3</inf> cycles are also studied. The simulation results demonstrate that adding LiBr and LiNO<inf>3</inf> salts improves the COP and reduces the initial temperature requirement in the generator of the VARS. Specifically, the NH<inf>3</inf>-H<inf>2</inf>O-LiBr cycle achieves the highest COP of 0.645 at an NH<inf>3</inf> mass fraction of 55% and a LiBr mass fraction of 25%. This represents an 8.81% improvement compared to the COP of the NH<inf>3</inf>-H<inf>2</inf>O cycle. Similarly, the NH<inf>3</inf>-H<inf>2</inf>O-LiNO<inf>3</inf> cycle exhibits the peak COP of 0.603 with the same NH<inf>3</inf> mass fraction and LiNO<inf>3</inf> mass fraction of 20%, which is 2.2% greater than the COP of the NH<inf>3</inf>-H<inf>2</inf>O cycle. Under similar operating conditions, the COP of the NH<inf>3</inf>-H<inf>2</inf>O-LiBr cycle is greater than that of the NH<inf>3</inf>-H<inf>2</inf>O-LiNO<inf>3</inf> cycle. © 2024 Elsevier Ltd