GoogleCodeExporter
commented
9 years ago The main problem with your model was that the BASESYS1 COILCLG-2 in the
BaseZnSys IT system had cfm/ton that was “out of range” as per EnergyPlus
calculations. Below are the details of this fatal error from the Eplus error
file:
For object = Coil:Cooling:DX:SingleSpeed, name = "BASESYS1 COILCLG-2"
** ~~~ ** Calculated outlet air relative humidity greater than 1. The combination of
** ~~~ ** rated air volume flow rate, total cooling capacity and sensible heat ratio yields coil exiting
** ~~~ ** air conditions above the saturation curve. Possible fixes are to reduce the rated total cooling
** ~~~ ** capacity, increase the rated air volume flow rate, or reduce the rated sensible heat ratio for this coil.
** ~~~ ** If autosizing, it is recommended that all three of these values be autosized.
** ~~~ ** ...Inputs used for calculating cooling coil bypass factor.
** ~~~ ** ...Inlet Air Temperature = 26.67 C
** ~~~ ** ...Outlet Air Temperature = 10.98 C
** ~~~ ** ...Inlet Air Humidity Ratio = 1.125000E-002 kgWater/kgDryAir
** ~~~ ** ...Outlet Air Humidity Ratio = 8.243136E-003 kgWater/kgDryAir
** ~~~ ** ...Total Cooling Capacity used in calculation = 5503.76 W
** ~~~ ** ...Air Mass Flow Rate used in calculation = 0.232462 kg/s
** ~~~ ** ...Air Volume Flow Rate used in calculation = 0.200578 m3/s
** ~~~ ** ...Air Volume Flow Rate per Watt of Rated Cooling Capacity is also out of bounds at = 3.6443769E-005 m3/s/W
** ~~~ ** During Warmup, Environment=IMPERIAL ANN CLG 0.4% CONDNS DB=>MCWB, at Simulation time=07/21 00:00 - 00:15
** Fatal ** Check and revise the input data for this coil before rerunning the simulation.
As indicated by the error description, I was able to run the model successfully
by reducing the cooling capacity from 18000 Btuh to 14000 Btuh. Alternatively,
an increase in fan capacity and system airflow would also address this issue.
The log file does point to “Full load outlet temperature indicates a
possibility of frost/freeze error continues” This is repeated for all the
coils. As per the Eplus error file, these are just warning messages and the
simulation will continue. However, it is likely that these conditions are
occurring because of low airflow relative to the specified cooling capacity,
similar to the situation with BASESYS1 COILCLG-2 above. Check that the airflow
to cooling capacity for your coils is in the range of 400 cfm/ton.
** Warning ** The Standard Ratings is calculated for Coil:Cooling:DX:SingleSpeed = BASESYS1 COILCLG but not at the AHRI test condition due to curve out of bound.
Other observations in the model were:
• Surface 360- is of type “underground floor”. This surface is part of
the 005 Plenum space and an underground floor seems out of place here. Please
verify the surface types.
• The SHW fluid segment has two supply segments- this is not allowed. Please
delete “BaseSHWPrimSupSeg-2”
CBECC-Com allows you to choose types of EPlus files saved during analysis on
your computer. This can be done by clicking on Tools in CBECC-com UI and
selecting Program and Analysis Options. This will bring up the window below: In
the drop down for Storage of Simulation Output choose 3 or above to ensure that
the Eplus error files are retained.
Energy Plus files of the file are typically saved in the same location as the
.cibd file. When an Analysis is performed on a CBECC model, a folder named
“cibdfilename” – run is created which will contain all the EPlus files.
The Name of the folder will be the same as the .cibd file name. Within this
folder you will find sub folders named ab (annual baseline), ap (annual
proposed) and zb(sizing baseline). Among other EPlus output files you will be
able to find the Error file in these folders. For your model, since the CBECC
log file points to errors in the proposed model, you may want to look at the
filer named eplusout in the ap folder.
Attached is the cibd with the changes mentioned above.
Original comment by cnambiar@archenergy.com on 3 Mar 2015 at 9:39
- Changed state: WontFix
Original issue reported on code.google.com by
f.le...@gmail.comon 27 Feb 2015 at 11:20