Semi-hermetics Or hermetics compressors - Please help

[chimbo]

My company is going to buy a Precision Environmental Control Airconditioned system for our Data Centre. Total cooling capacity is 47kW. Airflow is down flow. Totally new to aircon system. Am undecided on the type of compressors - 'Semi-hermetics Or hermetics'?
Most gtrateful if someone can help me on which type of comprssors. Thank you.

[The Viking]

Find a good A/C engineer / company and take his / their advice.

This is not a decision for an end user, there are much more important things for you to decide on, like backup/standby and so on.

Find a reputable company that done this type of installations before, then ask them to present you with the best options.

[chimbo]

Thanks. Have recieved offers from 2 different vendors. One of them offers semi-hermetics while the other offers hermetics compressors. Both aircons are reputable brands. Need help to choose which type.

[Brian_UK]

The way to chose is to establish the history of the suppliers.

Will they provide good service, good quality workmanship etc.

Ask for references.

When you built your server equipment did you base the purchase on the make of the hard drives or on the supplier quality?

[chimbo]

Thanks Brian. Actually, the new aircon is a replacement for an old reliable aircon.

[cameron.e]

here in sa we work with the hiross libit downflow serverroom a|c and it uses copland scrolls which is avery good comp if commissioned correctly ,the benifets of a scroll hermetic is that it has less moving parts compare to a recip

[chimbo]

here in sa we work with the hiross libit downflow serverroom a|c and it uses copland scrolls which is avery good comp if commissioned correctly ,the benifets of a scroll hermetic is that it has less moving parts compare to a recip

Thanks Cameron for your info. Currently our company is using Liebert PEC with semi-hermetic compressors. It has provide us faithful reliable service for more than 18 years. We are buying a new PEC aircon to replace it as a lot of the parts are obsolete. Our vendors are providing us with 2 types of PEC aircon with hermetics or semi-hermetics. Am just an end user. Need more advise from all on my choice of either Semi-hermetics Or hermetics compressors.

[750 Valve]

Well ifd you have a GOOD maintenance and repair company the semi will be more use to them when it fails - oil pumps, valveplates etc are all servicable/replacable (but they as stated before are additional moving parts to say a hermetic scroll). If had to choose semi vs hermetic recip the choice would be semi as it has similar operation but is servicable - the hermetic is not.
Hermitics are a product of our throwaway world and only make sense on small systems, semi's are a throwback to a time when a plant was engineered and installed to last for decades, just look at your old system.
I think you know what my vote is.

[chimbo]

Well ifd you have a GOOD maintenance and repair company the semi will be more use to them when it fails - oil pumps, valveplates etc are all servicable/replacable (but they as stated before are additional moving parts to say a hermetic scroll). If had to choose semi vs hermetic recip the choice would be semi as it has similar operation but is servicable - the hermetic is not.
Hermitics are a product of our throwaway world and only make sense on small systems, semi's are a throwback to a time when a plant was engineered and installed to last for decades, just look at your old system.
I think you know what my vote is.

thanks very much for vote

[Dr._Fleck]

The last time i saw a semi hemetic system i hurt my back lifting it out of a van, in fact that was the only system i've ever come across with a semi hemetic compressor. They are all hemetically sealed systems now. Mind you the a/c systems i fit are a lot smaller than 47kw(thank god)

[chimbo]

thanks a lot

[jose gonzalez]

I recomend semi hermetic comp. because of the capacity and the ability for easy manteinance. Hermetics are basically throwaway. Even thought you will take in account how you will manage the shutdown period because hermetics are faster to replace
THANKS
José Gonzalez

[chimbo]

I recomend semi hermetic comp. because of the capacity and the ability for easy manteinance. Hermetics are basically throwaway. Even thought you will take in account how you will manage the shutdown period because hermetics are faster to replace
THANKS
José Gonzalez

Thanks a lot Jose for your comments. Am learning a lot from the replies.

[The MG Pony]

Semi-Hermetic all the way!

[JFK]

i wont trade something else for a system that last 18 years. You don't want to change a compressor in a system, it's not a matter of just easy take off and put new one, there are down time, oil change, filter dryer change, gases......so i vote for more robust semi hermetic.

[Kh1971]

semi is much more better in service I think