[Bldg-sim] eQuest Default f(PLR) Skepticism

[Robby Oylear]

Okay, I think I understand now.  The EIR fPLR curve is not actually a
correction to the EIR efficiency, but to the total power draw of the
chiller.  I was calculating EIRFPLR as EIR(current conditions)/ EIR
(design conditions), when eQUEST wants it in the format of a power draw at
current conditions divided by the power draw at design conditions.

This also clears up another question I had which was why eQUEST calculates
the total power draw as a function of full load operating capacity and not
the actual load.  The EIRFPLR curve corrects it.

After fixing my equation the EIRFPLR values I received from the
manufacturer are within 2-7% of eQUEST default curves.

Thanks all for your help!

Robby Oylear
Project Engineer
direct: 206.788.4571
cell: 206.354.2721
www.rushingco.com

-----Original Message-----
From: John Aulbach [mailto:jra_sac at yahoo.com] 
Sent: Monday, February 04, 2008 10:35 AM
To: Robby Oylear; 'Aulbach, John'; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] eQuest Default f(PLR) Skepticism

I am sure we would welcome typical chiller data that
minimally complys.Remember that IPLV allows condenser
water relief for their calculations. eQuest needs
three curves including the kW/ton at CONSTANT
condenser water - then the program will "jump a curve"
to move the kW/ton to its location based on outdoor
air AND point on the part load curve.

Not always consistant, part load vs. outdoor air. I
believe Steve Gates has a comment on that in the
BLDG-SIM archives.



 
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