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Re: [EnergyPlus_Support] electric power (watts) of PTAC






Thank you for your specific explanation.
 
HVAC I used is the templated PTAC provided by EnergyPlus, that is, the heating is provided by electric power and cooling is supplied by cooling coil.
 
I calculate the fan electric power using the first method you provided, and find the maximum of fan electric power (W) is about 9W at the design day.

 
On Fri, Nov 20, 2009 at 10:49 AM, Richard Raustad <RRaustad@xxxxxxxxxxxx> wrote:
 

You need to identify the maximum power draw of your fan and compare that
to your design intent.

Report these 2 report variables:

Output:Variable,*,Fan Electric Power,timestep;
Output:Variable,*,Packaged Terminal Air Conditioner Fan Part-Load
Ratio,timestep;

and, if you are using an On/Off Fan object:
Output:Variable,*,On/Off Fan Runtime Fraction,timestep;

Maximum fan power is then roughly equal to Fan Electric Power / Packaged
Terminal Air Conditioner Fan Part-Load Ratio or is equal to Fan Electric
Power / On/Off Fan Runtime Fraction.

Another method is to either look for a time during the simulation when
the PTAC is operating at full load or force the PTAC to operate at full
load and then look at the reported fan power for that time period.

You will then need to determine if this maximum fan power is
representative of your system.
Fan power of 900 W sounds high for a PTAC (unless it is very large), my
AC system at 3 tons (10.5 kW) gives an estimated fan power of 0.018 W
per W of rated capacity.



Hu,Jia wrote:
>
> Thank you, Richard.
>
> It is realistic then to have the HVAC consumption of 200 W per hour
> (let's say on average) or in the range of 200-900 W per hour
> depending on a day, time, that is, external weather conditions.
>
--
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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