Dynamic Modeling and Simulation for Double Effect Absorption Refrigeration Using [mmim]DMP/CH3OH as Working Pairs

Abstract

The dynamic modeling and simulation based on components for parallel type and series type absorption refrigeration using novel working pairs [mmim]DMP/CH3OH were conducted. The modified UNIFAC model and Wilson model were used to describe the vapor liquid equilibrium and excess enthalpy of the [mmim]DMP/CH3OH solution, respectively. Under certain assumptions, the dynamic model was developed including the HPG (high pressure generator) model, the LPG (low pressure generator)-condenser model, the absorber-evaporator model and the SHX (solution heat exchanger) model. The effect of exhaust gas inlet temperature and chilled water inlet temperature on the thermodynamic performances were presented and discussed. The best COP of 1.27 and 1.17 for parallel type and series type system, respectively, were observed. The transient responses at step changes of two variables and on experimental conditions were carried out and analyzed, and the latter had been compared with the experimental data in literature. It is indicated that the model well describes the stable and transient characteristics of the double effect absorption refrigeration using [mmim]DMP/CH3OH, and can be employed to enable the further parameter optimization and control design.