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Screening of novel water/ionic liquid working fluids for absorption thermal energy storage in cooling systems
Author(s) -
Wu Wei,
You Tian,
Leung Michael
Publication year - 2019
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4939
Subject(s) - ionic liquid , crystallization , thermodynamics , chlorofluorocarbon , absorption (acoustics) , chemistry , work (physics) , thermal , materials science , analytical chemistry (journal) , physics , chromatography , organic chemistry , catalysis , composite material
Summary Absorption thermal energy storage (ATES) is significant for renewable/waste energy utilization in buildings. The ATES systems using ionic liquids (ILs) are explored to avoid crystallization and enhance the performance. Property model and cycle model have been established with verified accuracies. Based on the preliminary screening, seven ILs are found feasible to be ATES working fluids, while four ILs ([DMIM][DMP], [EMIM][Ac], [EMIM][DEP], and [EMIM][EtSO 4 ]) have been selected for detailed comparisons. The coefficient of performance (COP) and energy storage density (ESD) of the ATES using different H 2 O/ILs are compared with H 2 O/LiBr. Results show that the operating temperatures of LiBr are constrained by crystallization, limiting the COPs and ESDs under higher generation temperatures and lower condensation temperatures. With varying T g , [DMIM][DMP] yields higher COPs with T g above 100°C and [EMIM][Ac] yields comparable ESDs (67.7 vs 67.1 kWh/m 3 ) with T g around 120°C, as compared with LiBr. The maximum COP is 0.745 for [DMIM][DMP]. With varying T c , [DMIM][DMP] yields higher COPs with T c below 38°C and [EMIM][Ac] yields higher ESDs with T c below 33°C, as compared with LiBr. The maximum ESD is 87.5 kWh/m 3 for [EMIM][Ac]. With varying T e , [DMIM][DMP] yields higher COPs with T e above 8°C, as compared with LiBr. The maximum ESD of ILs is 104.0 kWh/m 3 for [EMIM][EtSO 4 ]. Comparing with the volume‐based ESDs, the differences between ILs and LiBr are smaller for the mass‐based ESDs. This work can provide suggestions for the selection of novel working fluids for ATES for performance and reliability enhancement.