Bitzer Vari-speed Compressors

[Coorsman777]

Looking at switching to Bitzer compressors on supermarket racks with lead comp being a Vari-Speed. Currently using Carlye's with an external VFD. Anyone with any experience good bad or otherwise would be appreciated.

Thanks

[THE DUDE]

I have not yet worked on a Octagon Varispeed. One thing to condsider is on a mechanical failure you are replacing the Compressor and the VFD vs just the Compressor. I can say that the Bitzers I have seen, have a very low failure rate. It would be intresting to see the price of a Varispeed vs a Remote VFD setup.

[Coorsman777]

The comp and VFD are separate components. If a comp goes bad you just change that and if the VFD goes bad you can just change that.

[THE DUDE]

Sounds like a good thing then, may be worth a try.

[Coorsman777]

Just found out another interesting bit of info. The heat sink for the VFD is cooled by the suction gas so it should increase the life of the VFD because it will run cooler.

[THE DUDE]

Just found out another interesting bit of info. The heat sink for the VFD is cooled by the suction gas so it should increase the life of the VFD because it will run cooler.
Cool. Have you checked the price diff ?

[Coorsman777]

Cheaper than a Carlyle with an external VFD. The only problem is that they only go up to a 9HP but they are able to go from 25hz to 87hz due to the fact they send 208 volt to the motor. It is a cool technology with some good science behind it.

[THE DUDE]

Cheaper than a Carlyle with an external VFD. The only problem is that they only go up to a 9HP but they are able to go from 25hz to 87hz due to the fact they send 208 volt to the motor. It is a cool technology with some good science behind it.

I agree. I was just thinking Carlyle seems to dropping behind on new technology. They did intoduce the "Smart Unloading" but I heard they are in a lawsuit with Copeland over it.

[mrfrze]

Bitzer NOW has the Vari-speed up to 20HP - all UL up to the F4 Inverter. FYI - Bitzer had Variable UNLOADING - Emerson sued them over that also!

[THE DUDE]

Bitzer NOW has the Vari-speed up to 20HP - all UL up to the F4 Inverter. FYI - Bitzer had Variable UNLOADING - Emerson sued them over that also!
That is good to see the larger capacity . I think this would be a nice upgrade for a Compressor changeout.

[HVACRsaurus]

Hi.

I'd be more inclined to go with an external VSD, pretty much any mainstream unit particularly if it has reasonable after sales support. As for the compressors, if they ain't broke, don't change 'em - you can usually fit VSD's to existing equipment.

Probably no real need to fit VSD to every compressor unless they got money to spare, just put VSD on one compressor & use it accordingly. ie,

1) start VSD comp, when it reaches maximum capacity
2) start next compressor in sequence (fixed speed is ok) & allow VSD comp to modulate
3) if fixed speed comp + VSD comp running flat out, start next compressor in sequence (again,fixed speed is ok) & allow VSD comp to modulate

Stage down in similar sequence, cycling off fixed speed compressors while the VSD comp modulates, untill VSD comp is last off.

[THE DUDE]

I would try to upgrade on a Compressor changeout ( Broken Compressor).
Either way is fine by me as long as there is a Bypass contactor installed.