A new absorption–compression refrigeration system for freezing application was proposed. In this
new system, the cascade use of mid-temperature heat source was implemented. The heat source could be
engine flue gas, process waste heat, or solar energy. The proposed system could be used as a stand-alone
unit to meet the low-temperature refrigeration load (approximately -55 °C) without additional electricity
or power input.
For the proposed system, the cooling capacity per unit mass of flue gas was 62.70 kJ/kg, and COP
reached 0.277; these values were higher by 45.78% and 49.73%, respectively, than those of the
conventional two-stage NH3/H2O absorption refrigeration system. The exergy efficiency in the new
system was 20.06%, which was 6.78 percentage points higher than that of the reference system.
The energy saving mechanism for the proposed system was recovered through exergy analysis. The
temperature match in the heat exchange processes between the working fluids and heat source was
improved dramatically. Consequently, the energy utilization was improved.
This study may provide a new efficient approach to produce low-temperature cooling energy using
mid-temperature heat source.