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Re: [EnergyPlus_Support] combined effect of shading devices on interior temperatures



1-5.  I would suggest studying the airflownetwork:multizone example files and 
reading the Engineering Document description of the models.  The relevant 
example files are AirflowNetwork3zVent, AirflowNetwork3zVentAutoWPC, and 
CrossVent_1Zone_AirflowNetwork.  I am not an expert in airflow modeling, and I 
am not sure how to find the relevant coefficients for various window openings.
6.  No, you do not need a mechanical system.  EnergyPlus can calculate the 
temperatures in unconditioned zones.  See example file 1ZoneUncontrolled.

7.  That is not completely true.  In the BUILDING object, is you use one of the 
FullInterior solar distribution options, then EnergyPlus will project direct 
sunlight through windows onto the appropriate interior surface and compute the 
temperatures accordingly.  But EnergyPlus does not alter the window properties 
when a window is open vs. closed.  The solar gains are as thought the window is 
always closed.  You say the window is always open for your simulation.  In that 
case, defined the window with a single pane of glass with near-zero reflectance 
and near-perfect transmittance (0.9999).

8.  There are many REPORT VARIABLES related to incident solar.  Add "report, 
variable dictionary, IDF;" to your input, run a simulation, and review the RDD 
output file for available report variables.

Mike


On 3 Jan 2008 at 12:39, neslihanturkmenoglu wrote:

> hi
> 
> I am simulating a cross ventilated zone  having an always open window 
> with shading device on the front and another opening always open at 
> the back  wall.I want to get interior surface temperature changes 
> according to shading device changes(concerning shading device effects 
> on airflow and solar radiation penetration to zone ). 
> 
> I know that program doesn't consider  shading devices  when modelling 
> airflows so I thought that if I calculate interior surface convection 
> coefficients with measured velocity coefficients and  discharge 
> coefficients with air mass flow  for  front opening  for all 
> situations of shading device alternatives and measured front and back 
> outside surface pressure coefficients, shading devices effects on  
> airflow would be considered.My questios are:
> 
> 1-  Which variables above should be entered as input to program? or 
> the program already calculates some of them?Ýs my discharge, 
> calculated with Q and pressure differences, same with the discharge 
> wanted in airflow network- simple or detailed opening object?Which 
> expression does EP use for calculating surface convection 
> coefficients? 
> 
> 2-To fill the air mass flow coefficient object in opening 
> definition,   How will I find out n(airflow exponent) and CT = 
> reference condition temperature correction factor (dimensionless). 
> 
> 3-For this simulation will I use UCSD (Cross Ventilation ) room air 
> models or airflow network or both of them?
> 4-Should I enter to program, the measured airflow velocities in wind 
> tunnel effecting my model,where?
> 
> 4-Should I put nodes ? Where should I put nodes? 
> 
> 5-Do I need to use any schedules for airflow and solar radiation 
> simulation.
> 
> 6-Natural ventilation effect the zone. There is no mechanical system, 
> no occupation, no lighting,etc.
> Do I need to define any mechanical system to run the program?
> 
> 
> 7-As I understand program is not able to give interior surface 
> temperatures of shaded and unshaded surfaces when solar radiation 
> enters through open window. Is it possible to define, for example-
> west interior wall as east outside wall and get interior surface 
> temperature or is there another way to consider solar radiation on 
> interior surfaces( I found the shaded anad unshade areas of interior 
> surfaces).If it is possible, will I first run the program with 
> airflow network simulation and get interior surface and interior mean 
> air temperature after that run the program for solar radiation 
> effects on surfaces(by defining cross walls as exterior walls) and 
> get surface temperatures and interior mean air temperature? and so 
> how will I find the the combined effect of shading devices on 
> interior surface and air temperatures according to airflow and solar 
> radiation penetration to interior?
> 
> 8-How will I  get the solar radiation intensities effecting ground or 
> side walls?
> 
> I am not an engineer and it is most of time hard to understand 
> manuels. Thank  you very much for your help. 
> Happy new year to all:)
> 
> 
> 
> 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.pdf under the
> Documentation link and press the "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 


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





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