[Bldg-sim] DX Cooling EIR Ratio Curve

[eric wang]

Jeff,
 
The system type is DX packaged single zone. From the hourly report, I found sometimes Temp correction to COOLING-EIR, Part load correction to COOLING-EIR and Operating EIR are zero when Cool on/off flag is on. Is there a specific condition that these parameters can equal zero? 
 
Thanks a lot
 
Shaojie










--- On Tue, 2/17/09, Jeff Hirsch <Jeff.Hirsch at DOE2.com> wrote:

From: Jeff Hirsch <Jeff.Hirsch at DOE2.com>
Subject: Re: [Bldg-sim] DX Cooling EIR Ratio Curve
To: shaojieworld2006 at yahoo.com
Cc: glenn.haynes at rlw.com
Date: Tuesday, February 17, 2009, 1:26 PM



don't forget that the COOL-FT-MIN is used as a minimum
value for the curve input for the extering condenser temperture.
COOL-FT-MIN is also for the evap min temperature into
the curve. So low OA temps and low entering wetbulb will not be
fully reflected into the curve values.
 
COOL-FT-MIN default
(cond temp curve low limit)
   water cooled 60
   evap cooled  50
   air or evap pre-cooled 70
(evap temp curve low limit)
   evap cooled COOL-MIN-T
   all others COOL-MIN-T - 10.0
--- 
Jeff Hirsch
James J. Hirsch & Associates
12185 Presilla Road
Camarillo, CA 93012-9243 USA
phone: (805) 553-9000
fax: (805) 532-2401
email: Jeff.Hirsch at DOE2.com
web: http://DOE2.com
skype: jeffhirschcamarillo 




----- Original Message ----- 
From: eric wang 
To: Glenn Haynes 
Cc: bldg-sim at lists.onebuilding.org bldg-sim at lists.onebuilding.org 
Sent: Tuesday, February 17, 2009 9:22 AM
Subject: Re: [Bldg-sim] DX Cooling EIR Ratio Curve






Jonathan and Glenn,
 
Thanks a lot for your replies. However, the values I calculated by using return or mixing air wet bulb temperatures are still different to the number listed in the hourly report. 
 
Thanks
 
Shaojie


--- On Fri, 2/13/09, Glenn Haynes <glenn.haynes at rlw.com> wrote:

From: Glenn Haynes <glenn.haynes at rlw.com>
Subject: RE: [Bldg-sim] DX Cooling EIR Ratio Curve
To: shaojieworld2006 at yahoo.com
Date: Friday, February 13, 2009, 3:08 PM



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The wet bulb temperature refers to that entering the evaporator, which is the return air wet bulb temperature.
 




From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of eric wang
Sent: Friday, February 13, 2009 1:48 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] DX Cooling EIR Ratio Curve

  






Hi,


 


I used the default DX Cooling EIR Ratio Curve (DX-Cool-Cap-fEWB&OAT) in eQUEST. The variables are t entering wetbulb and t enter condenser. I assume these refer to outside air wet and dry bulb temperatures. After exporting outside air wet and dry bulb temperatures in hourly report, the value of "Temp correction to COOLING-EIR" I calculated is different to the one in the hourly report by using the curve coefficients. Can anyone point out if my understanding is correct?


 


Thanks a lot for your help


 


Shaojie

  







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