5.8.3 cooling tower capacity adjustment - curve not generic

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What NACM Section(s) are relevant to this issue?

5.8.3 cooling tower capacity adjustment

Explanation of issue:

The form of the curves for cooling tower capacity adjustment are DOE-2 specific 
and should be made more generic to be able to be interpreted by other programs 
such as EnergyPlus.


Proposed resolution:




Please provide any additional information below.

Original issue reported on code.google.com by jglazer@gard.com on 21 Jun 2012 at 6:54

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I'm not sure of an easy solution for this one. The DOE-2 curves and E+ curves 
(either CoolTools or York model) are completely different in form.

I think it would be difficult to go from the DOE-2 default curve to the 
EnergyPlus curve which has as many as 35 coefficients. Easier to go from the E+ 
curve default (if there is one) to the DOE-2 curve.

Original comment by JohnJArent on 25 Jun 2012 at 9:48

• Changed state: Accepted

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John to follow up with Mark Hydeman and/or Dick Lord

Original comment by JohnJArent on 6 Sep 2012 at 9:52

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Current plan is to use DOE-2 defaults for DOE-2 and EnergyPlus defaults for 
EnergyPlus. Mark Hydeman says that both the DOE-2 and EnergyPlus curves are 
"pretty good". This is not an ideal solution but may work if the performance of 
the two is close enough. A brief investigation did not give any answers as to 
how close the two modeling approaches are.

Original comment by JohnJArent on 27 Sep 2012 at 12:12

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Original comment by JohnJArent on 27 Sep 2012 at 12:13

• Changed state: Started

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The resolution to this issue is to use the DOE-2 default performance curve for 
towers for DOE-2 software and use the EnergyPlus CoolTools curve for E+ 
software. Taylor Engineering indicated that both DOE-2 and E+ curves are 
"pretty good". The user cannot modify the default performance curves.

Original comment by JohnJArent on 21 Nov 2012 at 7:00

• Changed state: Fixed

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To support the Cool Tools model for cooling towers, I am proposing to add a new 
object and HeatRejection reference property to support the ACM cooling tower 
capacity curve

New Object: CurveCoolToolsCoolingTowerCapacity (CrvCoolToolsClgTowerCap)
Properties: 
WetbulbTemperatureMinimum (WBTempMin)
WetbulbTemperatureMaximum (WBTempMax)
RangeTemperatureMinimum (RngTempMin)
RangeTemperatureMaximum (RngTempMax)
ApproachTemperatureMinimum (ApproachTempMin)
ApproachTemperatureMaximum (ApproachTempMax)
WaterFlowRatioMinimum (WtrFlowRatMin)
WaterFlowRatioMinimum (WtrFlowRatMax)
+ the 35 Coefficient properties (Coeff1-35)

Add the following reference property to HeatRejection object:
Capacity_fCoolToolsCurveReference (Cap_fCoolToolsCrvRef)

Please let me know if this works for you all before the next rule author 
meeting (9am next Tues)

Original comment by da...@360-analytics.com on 5 Apr 2013 at 1:56

• Changed state: Discussion

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Haven't gotten any additional input, so will plan on adding these additional 
curve types to the SDD Update list later today.

Original comment by da...@360-analytics.com on 9 Apr 2013 at 4:48

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David's approach to support the CoolTools cooling tower model in EnergyPlus is 
appropriate. Let me know if any ACM changes are required.

Original comment by JohnJArent on 1 May 2013 at 8:37

• Changed state: Resolved

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Roger,
I was scrambling to get HVAC airside instances to NREL when I logged my last 
comment, so I never took any action on this.  Since you and Noah are now 
working on these rules, I suggest you guys add it to the SDD update list.

Original comment by da...@360-analytics.com on 1 May 2013 at 8:43

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OK, I'll take care of it.  

Original comment by rhedr...@archenergy.com on 1 May 2013 at 10:08

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I think this should be taken care of - assigning to Roger to verify that this 
has been done.

Original comment by JohnJArent on 19 Sep 2013 at 9:21

• Changed state: Fixed

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Cooling towers are now modeled with the cooltools curves in EnergyPlus.

Original comment by rhedr...@archenergy.com on 7 Feb 2014 at 5:58

• Changed state: DoneVerified