Analysis of NH3-H2O-LiBr absorption refrigeration integrated with an electrodialysis device

The addition of LiBr can significantly improve the performance of NH3-H2O absorption refrigeration system. It can also increase the ammonia concentration of the vapor stream, thus reducing energy consumption of rectification. However, the existence of LiBr has a negative effect on the absorber, especially at high LiBr mass fractions because it reduces the absorption capacity of the mixed ternary solution. This paper proposes a new NH3-H2O-LiBr absorption cycle that uses an electrodialysis device to separate the LiBr from the solution stream entering the absorber so that the LiBr is retained in the generator as much as possible. The model implemented in the ASPEN PLUS process simulator has been used to calculate the performance of the NH3-H2O-LiBr absorption refrigeration cycle. Simulation results indicate that, due to the integration of electrodialysis process, the operating temperature in the generator is significantly reduced and the COP of the proposed system is improved compared to the normal NH3-H2O-LiBr absorption refrigeration cycle when LiBr mass fraction varies from 0% to 50%.