Refrigeration & Equipment Engineering

Unit 3 - Parts of refrigeration systems

3.1.2.1.3.Important terms used in reciprocating compressor
B.D.C
When the piston reaches at the bottom of the cylinder of compressor is called Bottom Dead Center.

T.D.C
When the piston reaches at he top of the cylinder of compressor is called Top Dead Centre.

Piston stroke
The distance covered by the piston from B.D.C to T.D.C or T.D.C to B.D.C is called piston stroke.

Suction stroke
when the piston moves from T.D.C to B.D.C and sucks gas through the suction valve then it is called suction stroke.

Compression stroke
when the piston moves from B.D.C to T.D.C and compresses and discharges the gas through the discharge valve then it is called compression stroke.

Piston displacement volume
Total cylinder volume swept by the piston in any certain time is called piston displacement volume. It is expressed in cubic meter per minute

Compression ratio
compressor ratio is the ratio of absolute discharge pressure or head pressure to the absolute suction Pressure.

Volumetric efficiency
It is the ratio of actual weight of refrigerant in a cylinder to the weight that the cylinder can theoretically hold.