Energy and exergy analysis of parallel flow double effect H2O-[mmim][DMP] absorption refrigeration system for solar powered district cooling

Solar thermal energy-driven double effect absorption refrigeration system (DE-ARS) for district cooling in smart cities is an efficient, and sustainable alternative for centralized air conditioning and concurrently harnesses low-grade solar energy. This work investigates ionic liquid based H₂O-[mmim][DMP] mixture as an alternative working fluid to overcome the drawback of H₂O–LiBr driven DE-ARS. The thermodynamic properties of H₂O-[mmim][DMP] mixture is evaluated using the excess Gibbs free energy model. Performance modeling and simulation of DE-ARS is based on both energy and exergy analysis by applying the first and second laws of thermodynamic. The performance, and solution circulation ratio of parallel flow DE-ARS is assessed and optimized under various temperatures and solution distribution ratios. In comparison to the conventional H₂O–LiBr, the proposed H₂O-[mmim][DMP] working fluid achieves 5.22% and 4.95% improvement in COP and ECOP, respectively at T_h/T_e/T_a/T_c of 140/5/30/30°C . An optimization of generator temperature to achieve maximum COP and ECOP is performed for a wide range of evaporation temperature from 5 to 20°C and T_a/T_c from 30 to 40°C. An optimization of H₂O-[mmim][DMP] mixture driven DE-ARS reveals the uppermost COP_max and ECOP_max of 1.81 and 0.69 for T_e of 20°C and T_aT_c=30°C.

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Published in: Case Studies in Thermal Engineering
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.csite.2021.101382