technical NOTES

S.N. Description Reciprocating Screw

9 Air discharge Pulsating so require costly

piping

Continuous

10 Noise level Higher than 85 dBA Less than 85 dBA

11 Speed RPM of crank shaft is 850-

950 RPM, Lesser than Screw

compressor

RPM of female rotor is

more than 3000 RPM

12 Compression ratio For 2-Stage it is 2.5 in first

stage and 4 in second stage

This is single stage

machine so compression

ratio is 10, which is higher

than Reciprocating

compressor.

10.4 A Typical Cost Analysis

S. N. Make UOM Reciprocating Screw

Type of Compressor Reciprocating Oil Lubricated -

Screw

Type of Cooling Air Cooled Air Cooled

(^) Capacity CFM 955 943
m3/hr 1622 1610
Max. Working Pr. bar(g) 10 10
Nominal Working Pr. bar(g) 6.5 6.5
Motor Power KW 160 160
A Opex Cost
Measurement Standard Followed BS 1571-2:1975 ISO1217 Annex. C
Ed.04
Measured Capacity at Nominal
Working Pressure

CFM 756 948

Actual Power Consumed at

Nominal Working Pressure

KW 136 151.6

Power consumption during

Start-up

KW 14.7 0

Power consumption for P&V

System

Kw 33 0

Total Net Power Consumption KW 183.7 151.6

Specific Power Consumption KW/CFM 0.243 0.160

Power Tariff Rs./KWH 5 5