Calculation of Air Compressor

Air Compressor

GENERAL
Compressor is one such device which is used for several purposes on a ship. As the main aim of the compressor, as the name suggests, is to compress air or any fluid in order to reduce its volume. Some of the main applications of compressors are main air compressor, deck air compressor, AC compressor and refrigeration compressor.

Air Compressor produces pressurized air by decreasing the volume of air and in turn increasing its pressure. Different types of air compressors are used according to the usage.


Starting Air Compressor
The equipment provided for starting the engines must enable the engines to be started from the operating condition 'zero' with shipboard facilities, i. e. without outside assistance.

Two or more starting air compressors must be provided. At least one of the air compressors must be driven independently of the main engine and must supply at least 50 % of the required total capacity.

The total capacity of the starting air compressors is to be calculated so that the air volume necessary for the required number of starts is topped up from atmospheric pressure within one hour.

The compressor capacities are calculated as follows:

 

Where :

P [Nm3/h]  = Total volumetric delivery capacity of the compressors
V [litres]    =  Total volume of the starting air vessels at 30 bar service pressure
 see Calc. of starting air vessel for V capacity.

As a rule, compressors of identical ratings should be provided. An emergency compressor, if provided, is to be disregarded in this respect.


Hopefully helpfully 😊
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