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Re: [EnergyPlus_Support] Re: the condenser fan energy for air-cooled chiller





If you model the AIRCOOLED Chiller:Electric :EIR without using the input for Condenser Fan Power Ratio, then condenser fan power is included in the chiller power/energy calculation.
If you enter a value for Condenser Fan Power Ratio then the condenser fan power will be calculated separately and reside on a cooling plant electricity meter (and so other inputs, COP, curves, etc. should not include condenser fan power). The former will model variable speed condenser fans while the latter will model a single-speed condenser fan(s).

  Chiller:Electric:EIR,
    0.01,      !- Condenser Fan Power Ratio {W/W}

Then in the mtd you should see the condenser fan electric energy on the cooling plant meter.

On 4/24/2018 12:50 PM, Jim Dirkes jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support] wrote:
As usual, I agree with Mr. Marais. I'll add one clarification: 
  • Any (normalized to AHRI test conditions) curve set will result in the COP that is used as input for the E+ for the chiller.
  • If you want to match the chiller's IEER, however, the curves must ALSO be adjusted to match the part load performance.

On Tue, Apr 24, 2018 at 11:46 AM, fpasserini.tn@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 

I wrote to the helpdesk and it seems it's normal. From the Engineering Reference guide:

The amount of condenser fan energy is assumed to be proportional to the chiller
cycling ratio and is calculated as follows:

Pcond =Qref * (Pcondfanratio) * (ChillerCyclingRatio)

where ChillerCyclingRatio = min(PLR/PLRmin ; 1.0)

therefore the fan power is modulated only if PLR < PLRmin



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Posted by: Richard Raustad <rraustad@xxxxxxxxxxxx>


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