Re: [EnergyPlus_Support] Problems on air flow windows and cooling coil

["Michael J. Witte" <mjwitte@xxxxxxxx>]

1.This could be valid.  "Window Heat Loss" is heat flow from the zone into the 
window unit.  If cool air enters the window gap, it could increse the heat flow 
from the zone through the inner pane of glass.  If the "Window Gap Convective 
Heat Flow" is positive and greater than the change in "Window Heat Loss", then 
there is a net benefit from the airflow window.  See the Input Output 
Reference, p. 134, pdf p. 165, for explanations of the report variables.  If 
this does not explain what you are seeing, please submit your input file.

2a.  This is how it is designed to work.  From the Input Output Reference for 
SYSTEM SIZING:  "Field: Central cooling design supply air temperature:  
The design supply air temperature for cooling in degrees Celsius. This should 
be the temperature of the air exiting the central cooling coil."

2b. Try lowering the above value to account for the fan temperature rise.  If 
this does not solve the problem, then report the coil leaving temperature and 
setpoint to verify if the coil is controlling properly.  Also, check that the 
quantity of outside air specified in the SIZING objects is consistent with the 
outside air flow in the simulation.  The sizing calculations only know 
primarily the inputs in the SIZING objects.

Miie

On 17 Nov 2004, at 13:41, ekwtsang wrote:

> 
> 
> Dear all,
> I have two problems:
> 1. When i simulate the airflow window, it is found that during 
> winter,the gap convective heat loss and the window heat loss is 
> larger than the one without air window. However, the plant heating 
> load decrease.
> 
> 2. When I try to change the Coil:Water:simple to the 
> Coil:Water:cooling, it is found there are several problems.
> 
> 2a My system is a draw though system however the autosize outlet air 
> temperature is the same as my supply air temperature, it seems that 
> there must have some problem since it does not account the 
> temperature rise across the fan.
> 
> 2b after autosizing of the cooling coil, when i perform design day 
> simulation, the coil cannot fullfill its duty. Even I manully 
> decrease the leaving air temperature in the coil input.
> 
> Can anyone tell me how the use this coil and read the airflow window 
> output during winter.
> 
> Regards,
> Ernest Tsang
> 
> 
> 
> 
> 
> 
> 
> 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.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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