Recip Compressor - Loading Control (100% spill back versus suction Unloaders)

[planck121]

Hello,
I am presently involved in a project where we are planning to install two H2 recip machines. The question is operations at plant want a 100% spill back control of the machine. Personally myself I have seen 50% spill back control and 50% based on suction unloaders makes it more reliable. However the EPC company working on the project is suggesting that if we decide to go with 100% spill back then they will not want to provide suction unloaders. I am not sure if having no suction unloaders along with 100% spill back strategy is a good way to go, but in any case if we decide on a 100% spill back control the machine will not be provided with suction unloaders. Is this reasonble? what are some of the disadvantages only have 100% spill back without suction unloaders (if any), it does make sense that during a 100% spill back control the suction unloaders will be redundent. But does it provide reliability when having no suction unloaders.

Thanks in advance for the feedback

 

[CaracasEC]

The difference falls on energy wasted if you used 100% spillback. Remember that the input power is always larger if you used the spillback control compared to suction unloaders.

 

[nickelkid]

Apparently this is a 0 or 100% capacity application, if it is, I agree with CaracasEC, energy costs decide.