Re: [EnergyPlus_Support] Re: Natural ventilation by using Wind and stack area method?

["Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

First program your model so that you achieve the correct "infiltration" rates when all doors and windows remain shut. Don't look at ACH but consider the leakage per m2 of exposed surface area at a specific pressure difference. A recent ASHRAE research report said the US Army Corps standard is 0.25 L/s/m2 at 75 Pa. The newest ASHRAE 90.1 also has a standard. In Germany we used to use 0.3 ACH at 50 Pa and convert it to what that would be in L/s/m2 depending on the object, but I believe the newer norms have also switched to a L/s/m2 metric. I wrote an article were I suggested how you can set up the cracks of your AFN to achieve this.

WPC are either auto calculated by e+ or specified by the user. I believe DesignBuilder uses a different database to assign WPC and has good documentation online about the references. Check their program help. Else a CFD can find you the best WPCs.

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Now for window and door operation. Here you will get 40 ACH if you leave things open. However, your controls should ensure that windows don't open to ventilate at times of strong wind or cold outside conditions.

On 12 Feb 2016 3:30 pm, "ujjwal.mnit@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

While working on a Energy Plus 8.4 model, Windandstackopenarea module was used for introducing natural ventilation in house.

The average value of Air Change per Hour  for  a 3X3X3 m^3 house with 2 windows(east and north) of 0.8 m^2 each came to be  43.67 

This is too much to analyse effect of a solar chimney ventilation under natural ventilation. I want to reduce it under practical limits.

After going through the algorithm from source code, it was found that coefficient of wind is taken from 0.55 to 0.3 for relative angles 0 to 180 of wind and window normal with linear interpolation

What should be the range of values for Coefficient of wind to be used for above model if i dont want to use auto calculate?

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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>

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