If we are modelling a Chiller:ElectricEIR the EIRFPLR is only dependent on PLR but, as we can see on the manufacturer data for unloading, the inlet evaporator water temperature is very important to know how the chiller works because I think it modify Qavailable.The model in E+ suppose it always to Qref·CAPFT and I think this is not correct.
Ignacio Gomis
On 10 February 2012 19:50, Richard Raustad <
RRaustad@xxxxxxxxxxxx> wrote:
> No,. CAPFT describes the full-load capacity as water and air
> temperatures vary. The PLR curve takes into account the unloading. So
> Pref in your email describes the full-load power. If it is high, then
> the CAPFT curve is not accurate.
>
> On 2/10/2012 1:44 PM, Nacho Gomis wrote:
>> Hi,
>> we have been thinking on the same way.I noticed that the capacity
>> power was always so high for the calculation(CAPFTxNominalCapacity)and
>> it means for E+ that the electric consumption is not reduced so much.
>> This is a way to fix it but I think the problem is the Pref=Qref /
>> COPref x CAPFT which is very high,I think the CAPFT curve must be
>> reformulated and take into account the PLR.Because I have ran a
>> simulation which a chiller with a reference COP of 3 and the maximun
>> COP in my simulation was 6.7.
>> What do you think about the idea of adding a variable to CAPFT or
>> adding a new curve?
>> Thanks Richard,
>> Ignacio Gomis
>>
>> On 10 February 2012 18:51, Richard Raustad<
RRaustad@xxxxxxxxxxxx> wrote:
>>> 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
>>> 1679 Clearlake Road
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>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at:
http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
>
>
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