[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [EnergyPlus_Support] Re: 3rdOrderBackwardDifference in Energy Plus


The surface and air temperatures start at 23C.  



From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of bokelai1989
Sent: Thursday, August 16, 2012 10:34 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: 3rdOrderBackwardDifference in Energy Plus





Hi,
But in the initial calculation, where do the history temps come from when we are just provided with one desired zone temperature?

To be specific, to solve the ODES of temperature using the predictor-corrector approach, how does energy plus initialize the temperature values for the ODES? For example, given a weather data and ground temp, we know the outside temperature and the ground temperature. Also given the zone temperature schedule, we know the desired temperature for each zone.

My question is , in the energy equation, will the temperatures of inside and outside surface of each wall be also calculated through the integration method? How can we initialize these temperatures?

Thanks!
Best,
Na

--- In <mailto:EnergyPlus_Support%40yahoogroups.com>EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <<mailto:RRaustad@...>RRaustad@...> wrote:
>
> E+ saves the previous zone temps in history terms, t-1, t-2, t-3, and
> uses those as needed. Of course these are updated every time step (i.e.,
> using first in last out).
>
> On 8/16/2012 11:58 AM, bokelai1989 wrote:
> > Hi, All,
> > In the Engineering Manual of Energy Plus, it mentions a method of "3rdOrderBackwardDifference".
> >
> > It says "This algorithm requires zone air temperatures at three previous time steps and uses constant temperature coefficients. The assumption is that three previous time steps lengths are the same."
> >
> > I would like to know in terms of its inner calculation mechanism, how energy plus acquires the zone air temperature at three previous time steps?
> >
> > Thanks!
> > Na
> >
> >
> >
> > ------------------------------------
> >
> > Primary EnergyPlus support is found at:
> >
__._,_.___

Primary EnergyPlus support is found at:
<http://energyplus.helpserve.com>http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
<http://www.energyplus.gov>http://www.energyplus.gov

The group web site is:
<http://groups.yahoo.com/group/EnergyPlus_Support/>http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.


<http://geo.yahoo.com/serv?s=97476590/grpId=3387488/grpspId=1705007389/msgId=26317/stime=1345135375>

Your email settings: Individual Email|Traditional
<http://groups.yahoo.com/group/EnergyPlus_Support/join;_ylc=X3oDMTJmN2oyMHI2BF9TAzk3NDc2NTkwBGdycElkAzMzODc0ODgEZ3Jwc3BJZAMxNzA1MDA3Mzg5BHNlYwNmdHIEc2xrA3N0bmdzBHN0aW1lAzEzNDUxMzUzNzU->Change settings via the Web (Yahoo! ID required)
Change settings via email: <mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx?subject=Email Delivery: Digest>Switch delivery to Daily Digest | Switch to Fully Featured
<http://groups.yahoo.com/group/EnergyPlus_Support;_ylc=X3oDMTJkZWtpdWc4BF9TAzk3NDc2NTkwBGdycElkAzMzODc0ODgEZ3Jwc3BJZAMxNzA1MDA3Mzg5BHNlYwNmdHIEc2xrA2hwZgRzdGltZQMxMzQ1MTM1Mzc1>Visit Your Group  | <http://docs.yahoo.com/info/terms/> Yahoo! Groups Terms of Use  | <mailto:EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx?subject=Unsubscribe> Unsubscribe

__,_._,___