Re: [EnergyPlus_Support] Problems modeling a chiller

[Richard Raustad <RRaustad@xxxxxxxxxxxx>]

The EIRFPLR curve is  the part-load operating power divided by the 
available full-load capacity at the specific operating conditions. This 
means that if the power is 10 kW at a PLR = 0.5, with the CWT = 5 and 
the OAT = 25, then EIR = 10 kW divided by the full-load available 
capactiy (PLR=1) at CWT=5 and OAT = 25.

On the EIRFPLR tab, change column E to be C2/$B$2, C3/$B$2, C4/$B$2, 
etc. and then recalculate the coefficients. Tell me how this works. This 
assumes that the operating conditions are the same for all 4 rows (CWT 
and CDWT do not change).


On 2/10/2012 12:35 PM, Nacho Gomis wrote:
> Hi,
> finally I recalculated the performance curves and now the model is
> working.I had to set the condenser delta temperature to 5K because I
> had the leaving water condenser temperature provided by the
> manufacturer but I need the entering condenser temperature in order to
> model my chiller as Chiller:ElectricEIR.
> Now I'm focusing on how E+ control the chiller plant.I found a new
> variable for me:
> Chiller False Load Heat Trans [J]
> I understand it as wasting energy variable in order to met the cooling
> capacity supplied by the chiller and the required load supplied by the
> chilled water loop.
> I have been reading the EngineeringReference.pdf(page 550-55) but I
> have no any clear idea how E+ controls the plant.
> If I see the performance curves,they show that the chiller works
> better with PLR and my simulation shows in the wrong way,when the HVAC
> is working for low PLR the COP is very low.
> Could someone explain me it better?
> Thanks,
> Ignacio Gomis
> P.S.:I will attack the performance curve spreadsheet,the idf file, its
> rvi file and the csv file which is the result of the simulation.
>
> On 9 February 2012 16:24, Nacho Gomis<nachogo27@xxxxxxxxx>  wrote:
>> Without looking at your file…
>> ·         Does the pump have sufficient flow to properly transfer the 1MW?
>> Well,1MW is the cooling capacity,so the condenser will have a higher
>> value but never be 2MW.The pump flow rate is manually sized because
>> this data is provided by the chiller manufacturer,the value is
>> 0.05743m3/s and it is used in the corresponding field in the
>> ElectricChiller:ReformulatedEIR object.(Chiller model:Carrier 30XW
>> 1002)
>>
>> ·         Is the pump operating? (schedule = 1.0)
>> Yes,i have not scheduled the pump.It works fine with the template chiller
>> ·         Is the tower operating?
>> Yes,it has cooling capacity because I can see it in the output that
>> Richard told me in the message above.
>>
>> Thanks,
>> Ignacio Gomis
>
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-- 
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
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Cocoa, FL  32922-5703
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Fax:     (321) 638-1439 or 1010
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