Rotary compressors, common in many residential split air conditioners, use a rotating mechanism instead of a piston, generally offering smoother operation and improved efficiency, with fewer moving parts subject to wear compared to reciprocating designs. Scroll compressors, often found in larger commercial systems, use two interleaving spiral-shaped scrolls to compress refrigerant, offering high efficiency and relatively quiet operation, though repair typically requires full compressor replacement rather than component-level repair given their sealed, precision-manufactured construction.