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RE: [EnergyPlus_Support] Help
Joe,
Your concern would have absolute meaning if energy plus would have used finite volume heat and mass transfer code for doing heat balance. Unfortunately it doesnt. Jean email clarifies how it works. Yes there will be warning related to soler distribution as pointed out by Linda, similar to window mutipliar warnings. There are too many other greater approximations that make view factor concern negligibleand therefore for initial studies it can be workable according to my opinion.
Regards,
Adil
www.geedindia.org
From: <mailto:YJHuang@xxxxxxxxxxxxxxxxxxxxxxxx>Joe Huang
Sent: 23-02-2014 02:34
To: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Help
Just a note of caution.�� Not meaning to be confrontational in any way, but I'd like to know why Adil feels not having closure "doesn't matter"?
I haven't looked at this aspect of EnergyPlus, but from what I know of the heat balance method, the view factors should add up to 1.0.� If you tell me that the Simple Model simply (:-)) prorates view factors by the surface areas in that zone, adding up to 1.0, then that's fine, but if not, you might be having some "heat leak".
Joe
On 2/22/2014 11:33 AM, Jeremiah Crossett wrote:
> �
Adil,
Thank you much for taking a look and shearing your insight. �Great to know that my simplified modeling approach is reasonable and that the warnings can be safely ignored.�
The concept of modeling only roof or wall is really useful for initial studies, and I hope will be useful for exemplary calculations for LEED models that have been generated in other software that can not model PCM's. The idea is to model only the building elements of interest with an idealized HVAC system so that analysis and post processing are as simple as possible..�
> For the original users question, �I agree with Joe, Jean and Niraj that unless you are intending to model a part of a building such as I have that you should enclose your zones, but just mentioned my model to give an example how E+ could be used in this way..�
>
>
> Kind regards�
>
>
> Jeremiah D. Crossett��| Senior�Analyst��| �Phase Change Energy Solutions
120 E. Pritchard St. �| Asheboro, NC 27203�
�| Mobile�503-688-8951
<http://www.phasechange.com/>www.phasechange.com�
>
>
>
>
> On Sat, Feb 22, 2014 at 11:23 AM, Adil <<mailto:smhadil78@xxxxxxxxx>smhadil78@xxxxxxxxx> wrote:
>> �
>> Jermiah,
>> These warnings might have been put in EP for geometry integrity testing. Any cube or energy plus zone enclosure must have atleast 6 surface provided that you have define the zone by using buildingsurface:detailed object (this is default surface with many geometry export). In my opinion it dosent really matter for your model. You can safely ignore it. May be ep development team can note it and� instigate this warning only incase of Buildingsurface detailed objects and not in surface objects that you have used.
>>
>> Adil
>> <http://www.geedindia.org>>> www.geedindia.org
From: <mailto:jcrossett@xxxxxxxxxxxxxxx>Jeremiah Crossett
>> Sent: 20-02-2014 03:01
>> To: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
>> Subject: Re: [EnergyPlus_Support] Help [1 Attachment]
>>
>> �
>> Yea, it is quite useful to be able to do a simple model with the roof simple object-- so now I am a bit concerned-- if anyone has further opinions on the attached model that uses only a roof, zone area and ceiling height to calculate volume I would like to hear.. The model uses loads and schedules from the commercial reference primary school, but with a roof of an actual school. The goal of the model is to evaluate roof PCM capacity, SRI and U value and nothing more- so a surface model is used. �The file will open in open studio, but has some "Material Property Phase Change Dual Curve" objects from a custom version of E+ I use.
>> The specific error I get from the attached file is:�
>> �Program Version,EnergyPlus, Version 8.1, YMD=<tel:2014.02.18%2022>2014.02.18 22:51,IDD_Version 8.1.0.008
� �************* Beginning Zone Sizing Calculations
� �** Warning ** GetSurfaceData: The total number of floors, walls, roofs and internal mass surfaces in Zone GYMNASIUM
� �** � ~~~ � ** is < 6. This may cause an inaccurate zone heat balance calculation.
� �** Warning ** GetSurfaceData: The total number of floors, walls, roofs and internal mass surfaces in Zone CAFETERIA
� �** � ~~~ � ** is < 6. This may cause an inaccurate zone heat balance calculation.
� �** Warning ** GetSurfaceData: The total number of floors, walls, roofs and internal mass surfaces in Zone CLASSROOM
� �** � ~~~ � ** is < 6. This may cause an inaccurate zone heat balance calculation.
� �** Warning ** GetSurfaceData: The total number of floors, walls, roofs and internal mass surfaces in Zone CORRIDOR & OTHER
� �** � ~~~ � ** is < 6. This may cause an inaccurate zone heat balance calculation.
� �** Warning ** Surfaces in Zone="GYMNASIUM" do not define an enclosure.
� �** � ~~~ � ** Number of surfaces <= 3, view factors are set to force reciprocity.
� �** Warning ** Surfaces in Zone="CAFETERIA" do not define an enclosure.
� �** � ~~~ � ** Number of surfaces <= 3, view factors are set to force reciprocity.
� �************* Testing Individual Branch Integrity
� �************* All Branches passed integrity testing
� �************* Testing Individual Supply Air Path Integrity
� �************* All Supply Air Paths passed integrity testing
� �************* Testing Individual Return Air Path Integrity
� �************* All Return Air Paths passed integrity testing
� �************* No node connection errors were found.
� �************* Beginning Simulation
� �************* Simulation Error Summary *************
� �************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
� �************* EnergyPlus Sizing Error Summary. During Sizing: 6 Warning; 0 Severe Errors.
� �************* EnergyPlus Completed Successfully-- 6 Warning; 0 Severe Errors; Elapsed Time=00hr 01min 46.73sec
>>
>>
>>
>>
>>
>>
>>
>> Jeremiah D. Crossett��| Senior�Analyst��| �Phase Change Energy Solutions
120 E. Pritchard St. �| Asheboro, NC 27203� �| Mobile�503-688-8951
<http://www.phasechange.com/>www.phasechange.com�
>>
>>
>>
>>
>> On Wed, Feb 19, 2014 at 1:06 PM, Niraj Poudel <<mailto:nirajpdl@xxxxxxxxx>nirajpdl@xxxxxxxxx> wrote:
>>> �
The v
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