[Equest-users] Modeling Variable Speed Air Cooled Screw Chillers

[Carol Gardner]

Mohammad,

I will answer you if you don't mind. Tell the manufacturer that you need to
know how the chiller unloads based on the outside air temperature (DBT) and
the leaving chilled water temperature (CHWT), in other words, the chilled
water temperature you are delivering to your systems. You will find when you
go into your online help manuals that you need to normalize all your data
around the ARI design conditions. That means that your EIRs will look like
1.0, 1.09, .98, etc., depending on whether your part load EIR is higher or
lower than the EIR at the ARI design condition. If that is confusing to you
still, after doing your diligence and reading the DOE2/eQUEST online help
manuals, let us know.

Carol

On Wed, Aug 18, 2010 at 10:26 AM, Mohammad Almasri <malmasri at ems-int.com>wrote:

> Dear Paul,
> how I can get those data points to build the EIR-fPLR&DT curve? is it
> available in the manuals and chillers data sheets? or I should ask it from
> the suppliers directly?
>
> Please advice,
>
> Mohammad Al-Masri
> Simulation Engineer
> LEED AP BD+C, CAPM
>
> On Tue, Aug 17, 2010 at 4:45 PM, Paul Riemer <Paul.Riemer at dunhameng.com>wrote:
>
>>  If you ask a manufacturer's rep how a chiller unloads at part load, the
>> answer might be "good".  So I suggest you specifically request part load
>> points at 10% intervals with and without AHRI condenser relief.  That should
>> enable you to make or confirm both the EIR-fPLR&DBT and the EIR-fCHWT&DBT
>> curves.
>>
>>
>>
>> If you want to go even deeper, you could ask for those part load points at
>> different chilled water supply temperatures and then make or confirm a
>> Cap-fCHWT&DBT curve.  That seems like overachieving to me, but my chilled
>> water supply temperatures rarely deviate very far from AHRI standard
>> conditions.
>>
>>
>>
>> Good luck,
>>
>>
>>
>> *Paul Riemer, PE, LEED AP*
>>
>> Associate / Mechanical
>>
>> Direct: 612-465-7696
>>
>>
>>
>> *DUNHAM*
>> Celebrating 50 Years of Service
>>
>>
>>
>>
>>
>>
>>
>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Carol Gardner
>> *Sent:* Tuesday, August 17, 2010 9:22 AM
>> *To:* Mohammad Almasri
>> *Cc:* eQUEST-users at onebuilding.org
>> *Subject:* Re: [Equest-users] Modeling Variable Speed Air Cooled Screw
>> Chillers
>>
>>
>>
>> Mohammad,
>>
>> You will need to ask the manufacturer for information on how the chiller
>> unloads at part load so you can create an EIR-FPLR curve of your own. That
>> shouldn't be too hard. It looks like there's no problem with having the
>> water from the chillers flow using variable speed pumps so that part's there
>> if you want it. Let me know if you need help creating a curve.
>>
>> Carol
>>
>> On Tue, Aug 17, 2010 at 1:54 AM, Mohammad Almasri <malmasri at ems-int.com>
>> wrote:
>>
>> Hi all,
>>
>> How we can model a Variable Speed "Air Cooled" Screw Chillers in eQUEST?
>> The
>> available variable speed chillers curves in eQUEST are only for the
>> centrifugal .
>>
>> Thanks,
>>
>> Mohammad Al-Masri
>> Simulation Engineer
>> LEED AP BD+C, CAPM
>>
>>
>>
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>>
>>
>>
>> --
>> Carol Gardner PE
>>
>
>


-- 
Carol Gardner PE
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