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Re: [EnergyPlus_Support] Zone heating loads and heating meter not equal



Setting the pump head to zero gives me 1.25 (instead of 1.06) and 0.52
(instead of 0.47).
I can see what you mean by the chiller COP varying now. The chiller output
meets the chiller electricity * the chiller COP now.
The boiler output is still some way form meeting the boiler electricity, and
does not balance after a long time.

So...

Chiller Electric Power is virtually equal to cooling electricty
Chiller electric power x COP is virtually equal to both (total zone cooling
coil use + chilled water pump electricity) and chiller evap heat trans rate.

However, Boiler electric power and Heating electricity are not quite equal
and Boiler electric power is not close to equalling (total zone cooling +
hot water pump electricity). Any ideas?

Sam

 5/26/06 5:10 AM, "Michael J. Witte" <mjwitte@xxxxxxxx> wrote:

> Are you allowing for pump heat in the hot/chilled water loops?  Try setting
> the 
> pump head to zero to eliminate pump heat, then check again.  Also, the chiller
> efficiency is probably not constant (unless you are using the constant COP
> chiller).  First, check that the chiller evap heat transfer load matches the
> coil loads (plus pump heat).  Then look at the chiller COPs to  see if the
> electric consumption is reasonable.  Also, if the chilled/hot water loop
> temperatures are not maintaining setpoint at all times, there will be an
> imbalance until the loop returns to setpoint, but the energy should balance
> when summed over time.
> 
> Mike
> 
> 
> On 25 May 2006 at 18:05, Sam Roose wrote:
> 
>> > I have just uploaded a file called "DESIGN_DAY_WEATHERFILE" that works
>> fine,
>> > except that the sum of the zone heating loads in the output file (total
>> > water heating coil energy for 25 zones) does not equal the "Heating:
>> > Electricity" meter, which is the same value as the boiler electricity once
>> > converted to kWh. The same occurs with cooling (sum of total water cooling
>> > coil rate vs cooling:electricity). With the file I have sent, the sum of >>
the
>> > heating coils is 1.06 of the heating meter (should be 1.00) and the sum of
>> > the cooling coils is 0.47 (should be 0.33 due to a COP of 3 being used).
>> > 
>> > I have noticed I can bring the zone heating load sum more into line with >>
the
>> > heating meter by changing the maximum and minimum supply temperatures in >>
the
>> > autosizing inputs, but the values diverge again if I make a major design
>> > change.
>> > 
>> > The file was set up in version 1.2.3
>> > 
>> > Is the sum of the zone heating loads independent from the weather file? Is
>> > there some other reason this occurs?  Thanks in advance
>> > 
>> > Sam Roose
>> > 
>> > 
>> > 
>> > 
>> > The primary EnergyPlus web site is found at:
>> > http://www.energyplus.gov
>> > 
>> > The group web site is:
>> > http://groups.yahoo.com/group/EnergyPlus_Support/
>> > 
>> > Attachments are not allowed -- please post any files to the appropriate
>> folder
>> > in the Files area of the Support Web Site.
>> > 
>> > EnergyPlus Documentation is searchable.  Open EPlusMainMenu.idf and press
>> the
>> > "search" button.
>> >  
>> > Yahoo! Groups Links
>> > 
>> > 
>> > 
>> >  
>> > 
>> > 
>> > 
>> > 
>> > 
> 
> 
> ========================================================
> Michael J. Witte, GARD Analytics, Inc.
> EnergyPlus Testing and Support
> EnergyPlus-Support@xxxxxxxx
> 
> 
> 
> 
> 
> The primary EnergyPlus web site is found at:
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> 
> The group web site is:
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> Attachments are not allowed -- please post any files to the appropriate folder
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> 
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