Which one of the following statements is true?
1
Compared to reciprocating compressor, the performance of centrifugal compressor is less sensitive to speed.
2
Surging in centrifugal compressor takes place as evaporator pressure increases and condenser pressure decreases.
3
Surging in centrifugal compressor takes place as evaporator pressure decreases and condenser pressure increases.
4
For a given flow rate, frictional losses decrease as the number of blades increases.