Higher Efficiency, Lower Sound, and Lower Cost Air Conditioning Compressors: Part 2 - Sound/Discharge Pulse

This two-part paper describes a compressor redesign program for improving efficiency, lowering sound emission, and cost. Part 2 indicates how sound and discharge pulse were reduced through research conducted on transmission loss of plastic vs. steel manifolds and discharge pulse modeling using four pole parameters Common reciprocating compressors utilize steel flapper valves and a Cylinder Head that encloses a suction and discharge plenum. In these compressors, the suction gas enters the cylinder head into the suction plenum, passes through a steel flapper valve into the cylinder on the suction stroke, is compressed on the discharge stroke and is forced through a steel flapper valve into the discharge plenum. Heat transfer occurs from the high temperature discharge plenum to the low temperature suction plenum across the cylinder head wall which separates the plenums. In the Inertia compressor the gas flow and valve system is improved, resulting in cooler gas entering the cylinders 311d reduced flow losses through the valving. The suction gas is routed through the crankcase wall, through the piston, and enters the cylinder past a polymeric suction valve that floats freely on top of the piston. The free-floating valve results in increased valve open time and decreased flow losses. On the discharge stroke the gas is compressed and forced· past a polymeric discharge valve ; hat allows a large flow area with significantly reduced reexpansion volume. The cylinder head on this compressor is devoted entirely to the discharge plenum. The result of the cooler suction gas into the cylinder and reduced flow loss through the valve system is a very high-efficiency reciprocating compressor. The trade off for the efficiency improvement is in higher air-borne sound and higher cost than with Bristol Compressors standard product line, although the Inertia compressor remains very competitive in both sound and cost with competitive products.