[Equest-users] Constructing chiller part load curves

[Carol Gardner]

Afaan,

David is right, you need more points; eQUEST can accept up to 20 but 12 will
get you where you need to be. In addition to the document David has sent
you, please read the attached write up.

Any wiki or website people out there that want to post this online, or tell
me how to, please feel free to do so.'

Best,

Carol

On Wed, Jan 19, 2011 at 5:37 AM, David Eldridge <dse at grummanbutkus.com>wrote:

> You may want to run through this document before you get too much further.
> Skip ahead to “Part 2” of the document.
>
>
>
>
> http://www.energydesignresources.com/media/2654/EDR_DesignGuidelines_%20HVAC_Simulation.pdf
>
>
>
> In a nutshell – you should acquire a few more data points to develop a more
> comprehensive matrix.  Right now your matrix would be equivalent to a line
> through the middle of possible conditions, you need to extend your data set
> over a wider range of water temperatures and load conditions.
>
>
>
> David
>
>
>
> *
> *
>
>
>
> *David S. Eldridge, Jr.**, P**.**E**.**, LEED AP BD+C, BEMP, HBDP*
>
> Project Manager
>
>
>
> Direct: (847) 316-9224 | Fax: (847) 328-4550
>
> http://www.grummanbutkus.com
>
>
>
> *Grumman/Butkus Associates* | 820 Davis Street, Suite 300 | Evanston, IL
> 60201
>
> Energy Efficiency Consultants and Sustainable Design Engineers
>
> *
> *
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Afaan Naqvi
> *Sent:* Tuesday, January 18, 2011 8:33 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Constructing chiller part load curves
>
>
>
> After browsing the forums, it seems there are many users that have
> constructed custom chiller curves based on selection data. I believe I have
> all the data I need to do this, but am coming up with polynomial
> coefficients and hourly results that do not make sense at all. Can someone
> please walk me through how to go about building the 3 curves for a
> centrifugal, water cooled chiller with a VSD based on the following data:
>
>
>
> % Load
>
> Capacity
>
> kW in
>
> Perf
>
> Evap T in
>
> Evap T out
>
> Conden T in
>
> Coned T out
>
> 100
>
> 85
>
> 53.6
>
> 0.63
>
> 54
>
> 44
>
> 85
>
> 94.8
>
> 75
>
> 63.8
>
> 29.8
>
> 0.47
>
> 51.5
>
> 44
>
> 75
>
> 82
>
> 50
>
> 42.5
>
> 13.3
>
> 0.31
>
> 49
>
> 44
>
> 65
>
> 69.5
>
> 25
>
> 21.3
>
> 6.9
>
> 0.32
>
> 46.5
>
> 44
>
> 65
>
> 67.2
>
>
>
>
>
> I believe the additional data I need is calculated below, except for the dT
> term which I am unclear on:
>
>
>
> Load
>
> PLR
>
> kW
>
> f PLR
>
> 85
>
> 1
>
> 53.6
>
> 1
>
> 63.8
>
> 0.751
>
> 29.8
>
> 0.556
>
> 42.5
>
> 0.500
>
> 13.3
>
> 0.248
>
> 21.3
>
> 0.251
>
> 6.9
>
> 0.129
>
>
>
>
>
> Not sure if the dT term required by the curves is the difference in
> condenser supply and return, or condenser and evaporator supply, condenser
> supply and evaporator return, etc. Can someone please clarify?
>
>
>
> Thanks
>
>
>
>
>
> *Afaan Naqvi ** *PE  LEED AP**
>
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-- 
Carol Gardner PE
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