Performance analysis of the single-stage absorption heat transformer using a new working pair composed of ionic liquid and water

摘要

The performance simulation of a single-stage absorption heat transformer using a new working pair composed of ionic liquids, 1-ethyl-3-methylimidazolium dimethylphosphate, and water (H_2O + [EMIM] [DMP]), was performed based on the thermodynamic properties of the new working pair and on the mass and energy balance for each component of the system. In order to evaluate the new working pair, the simulation results were compared with those of aqueous solution of lithium bromide (H_2O + LiBr), Trifluoroethanol (TFE) + tetraethylenglycol dimethylether (E181). The results indicate that when generation, evaporation, condensing and absorption temperatures are 90℃, 90℃, 35℃ and 130℃, the coefficients of performance of the single-stage absorption heat transformer using H_2O + LiBr, H_2O + [EMIM][DMP] and TFE + E181 as working pairs will reach 0.494, 0.481 and 0.458 respectively. And the corresponding exergy efficiency will reach 0.64, 0.62 and 0.59, respectively. Meanwhile the available heat outputs for per unit mass of refrigerant are 2466 kJ/kg, 2344 kJ/kg and 311 kJ/kg, respectively. The above excellent cycle performance together with the advantages of negligible vapor pressure, no crystallization and more weak corrosion tendency to iron-steel materials may make the new working pair better suited for the industrial absorption heat transformer.