Indicated Horsepower (IHP)

The power required to compress the gas in one end of a reciprocating compressor cylinder from its suction connection to its discharge connection, exclusive of any mechanical losses such as piston ring and piston rod sealing ring friction; also the power measurement obtained from an analyzer with a pressure transducer connected to a port communicating directly with the internal volume on one end of a reciprocating compressor cylinder and time-phased to piston position or crankshaft angular position.