|
Posted by New Directions In Building Ser on June 4, 2007, 5:44 am
One of the good things about Liebert is that their tech support people are
willing to help you out - Call them.
Yes you do need to think along the lines of a COP of between 2.5 & 3.5 so
the refrigeration side will be 30%~40% of the equipment load in kWh (not kW
so if you want the unit to cycle off or have some redundancy then make it a
bit bigger but not too much) then multiply this by 40% for the fan load and
add it (this can be kW because they'll always be running), plus 8kW/unit for
the humidifier and whatever the rating of the reheat element.
I can provide a presentation for close control equipment selection for data
centre's - remove the nopam from my address and send a request if you think
that would be helpful.
>
>>I am retro-fitting a small 1600sqft datacenter with one or two Liebert
>> units (480V 3-PH).
>>
>> Can anyone tell me the realistic power draw of these units when in
>> full operation mode?
>>
>> I will either be using a 10-ton or 20-ton unit.
>>
>> Alot of people have been telling my that rule of thumb is 1KW per 1
>> ton, so a 10-ton Liebert should draw 10KW of power.
>>
>> If my math is right, a 10-ton Liebert pulling 10KW while in operation,
>> would be pulling approx 12amp per phase.
>>
>> 480V x A x 1.732 = 10KVA, so A = 12
>>
>> The reason why I bring this up is because I was talking to the
>> buildings electrical contractor about the power feeds to the space,
>> which is 200amp 480V 3-PH. I mentioned a single 10-ton Liebert, and he
>> said he usually wires those as a 60amp 480V circuit - which seemed
>> overly high? 60amp breaker, when your only pulling 12-15amps per
>> phase?! I know there can be startup surges, but 60amp seems really
>> high.
>>
>> Any thoughts?
>>
>
> I don't see why would you ask some thing like that
> just look up manufacture tag and in most cases
> you will find they recommendation isn't that simple
> or literature that comes with unit.
> This units almost always have two compressors
> and they also have heaters depend on model
> so little extra power doesn't hurt but less will.
> Tony
>
>
>
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap