How does absorption refrigeration differ from vapor compression refrigeration?

Absorption refrigeration uses heat energy instead of mechanical work to drive the refrigeration cycle. It employs an absorber-generator pair instead of a compressor, with refrigerant-absorbent pairs like ammonia-water or water-lithium bromide. Heat input vaporizes refrigerant from solution in the generator, while absorption process in absorber creates low pressure for evaporation. Though having lower COP (0.7-1.2), absorption systems utilize waste heat or solar energy, operate quietly with few moving parts, and suit applications where heat is readily available.