Performance analysis of ionic liquids for simultaneous cooling and heating absorption system

초록

A new working fluid for simultaneous cooling and heating absorption system, which is a combination of type 1 and type 2 absorption systems, was analyzed by simulation analysis. An imidazolium-based ionic liquid (IL) was used as an absorbent in the new working fluid and H2O and R32 were used as refrigerants. The states of the solution mixed with the refrigerant and absorbent were predicted using a non-random two-liquid (NRTL) model. The ILs with H2O refrigerant were 1,3-dimethylimidazolium dimethylphosphate ([DMIM][DMP]), 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM][DMP]), and 1-ethyl-3-methyl tetrafluoroborate ([EMIM] [BF4]), and the IL with R32 refrigerant was 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HMIM][Tf2N]). Changes in the cooling, heating, and total coefficient of performances (COPs) according to the generation temperature and generator and condenser split ratios were analyzed. It was concluded that H2O/ [DMIM][DMP], H2O/[EMIM][DMP], and H2O/[EMIM][BF4] were suitable for simultaneous cooling and heating absorption systems with reasonable cooling, heating and total COPs. However, R32/[HMIM][Tf2N] had ad-vantages for subzero cooling temperature and compactness of system size, while its COPs were lower than those of H2O/[DMIM][DMP], H2O/[EMIM][DMP], and H2O/[EMIM][BF4]. The total COP of H2O/[DMIM][DMP] was 0.98, indicating the highest performance. H2O/[EMIM][DMP] and H2O/[EMIM][BF4] exhibited total COPs of 0.96 and 0.97, whereas R32/[HMIM][Tf2N] showed a value of 0.55, under certain simulation conditions.

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