Numerical investigation of the thermal performance of compressor-assisted double-effect absorption refrigeration using [mmim]DMP/CH3OH as working fluid

The thermal performance of compressor-assisted double-effect absorption refrigeration (CDAR) was numerically investigated and comprehensively analyzed with 1, 3-dimethylimidazolylium dimethylphosphate/methanol ([mmim]DMP/CH3OH) as working fluid. The CDAR system was modeled and simulated based on the proposed mathematical model of the compression process by considering the mass and energy conservation of each component. The effects of compression ratio and heat source temperature on the system's operating state, including solution temperature, refrigeration concentration, mass flow, and heat load of each component, were calculated and discussed. Variations in the coefficient of performance and exergy efficiency in four cases were simulated and compared. Results suggested that placing the assisting compressor between the evaporator and absorber was a good option, and placing the assisting compressor between two generators was also acceptable. The exergy losses of each component were calculated and compared. The largest exergy loss occurred in the low-temperature generator and accounted for approximately one-third of the total exergy input. The main reason for the exergy loss in the diffusion absorption refrigeration system was heat transfer with a temperature difference.