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Re: [EnergyPlus_Support] FullInteriorandExterior working with non-convex zones???





If energy is conserved, then there will be no double counting as I thought in my last response...Making the non-perfect solution even more perfect. Brent summed it up nicely.

TrnSys went through a similar learning curve and now also provide a "detailed" algorithm. FullExterior works well, but as soon as you're in a situation where a lot of radiation should exchange or even travel directly back out the window it came from, then you're looking at up to 20%  zone solar heat gain differences...so for shallow zones with large windows, you had better use "more" than FullExterior, IMO, even if you incure other inaccuracies.

On 16.09.2014, at 18:31, "'Brent Griffith' brent.griffith@xxxxxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

The documentation and program has to be bit conservative and so to play it safe there are lots of warnings about it.  The solar distribution model was developed for convex zones, which are easier to model, and the thinking is that a more detailed solar distribution model is really needed to â??accuratelyâ?? model non-convex zones.   But applying the model to non-convex zones is not really all that bad in my view.  The solar gets spread out across the inside faces more broadly than it should.  Surfaces down a seemingly dark passage in an â??Lâ?? shaped zone will get a bit too much solar (and exchanges infrared with too many surfaces).  But energy is conserved and it is added to the right zone one way or another.  FullInteriorExterior is going to work better on a non-convex zone than the other choices.   In my view, slightly non-convex zones are not really a severe problem and the inaccuracies are worth accepting when the use of non-convex zones improves how one can zone a particular building.

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Tuesday, September 16, 2014 9:56 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: RE: [EnergyPlus_Support] FullInteriorandExterior working with non-convex zones???

 

 

The doubt is regarding non convex zones because depending on the surface the window is on there is no Energyplus Severe error but I still am uncertain that the calculation is right because of the manual states that the zones must be non-convex.

 

A good (and I think simple) improvement would be the possibility to specify the algorithm for each zone (or for a particular zone). This would be useful for special zones such as thrombe walls, double skins, greenhouses... which may be a reduced number of zones (or just one) in the whole model.



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Posted by: "jeannieboef@xxxxxxxxx" <jeannieboef@xxxxxxxxx>


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