Hello,
It's normal. The objectif of a steady state simulation it's to see what happens on extreme conditions, fox ex, in winter, no occupation, no sun, lowest temperature, etc... you can know the power of your equipement (boiler, chiller, etc). You simulate the coldest day and the hotest day.
A dynamic simulation it's to know the behaviour of the building, when there are people, lights, equipements, etc.... the systems power and loads are lower than steady simulation, as you said 25-40% are normal values.
You can't compare theses simulations, steady simulation gives the real power systems and dynamic gives you the opportunity to optimise your building.
good luck!
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: direzionecontraria@xxxxxxxx
Date: Sat, 27 Oct 2012 14:53:40 +0000
Subject: [EnergyPlus_Support] Re: dynamic vs. steady state (E+ significantly under predicting energy demands)
I cannot answer, but utilization factor of heat gains has a great important in semi-steady state methods.
Try to read the following articles:
https://lirias.kuleuven.be/bitstream/123456789/204376/1/Whole+Building+IX+Comparison+of+steady-state+and+dynamic+building+energy+simulation+programs.pdf
http://www.sciencedirect.com/science/article/pii/S0378778806001861
With Regards a
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Joe" <joebater@...> wrote:
>
> does anyone have any idea why discrepancies between E+ and simple steady state calculations, e.g. Q = U.A.dT, are so severe? despite it being a dynamic modelling approach you'd think that in the long term (e.g. a year) the two methods would have a reasonable harmony, instead I'm often finding 25-40% under-prediction in E+ compared to steady state for some simple buildings...
> is there a recommended report for building fabric heat losses?
> best regards and thanks in advance for any advice
> j.
>
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Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
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It's normal. The objectif of a steady state simulation it's to see what happens on extreme conditions, fox ex, in winter, no occupation, no sun, lowest temperature, etc... you can know the power of your equipement (boiler, chiller, etc). You simulate the coldest day and the hotest day.
A dynamic simulation it's to know the behaviour of the building, when there are people, lights, equipements, etc.... the systems power and loads are lower than steady simulation, as you said 25-40% are normal values.
You can't compare theses simulations, steady simulation gives the real power systems and dynamic gives you the opportunity to optimise your building.
good luck!
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: direzionecontraria@xxxxxxxx
Date: Sat, 27 Oct 2012 14:53:40 +0000
Subject: [EnergyPlus_Support] Re: dynamic vs. steady state (E+ significantly under predicting energy demands)
I cannot answer, but utilization factor of heat gains has a great important in semi-steady state methods.
Try to read the following articles:
https://lirias.kuleuven.be/bitstream/123456789/204376/1/Whole+Building+IX+Comparison+of+steady-state+and+dynamic+building+energy+simulation+programs.pdf
http://www.sciencedirect.com/science/article/pii/S0378778806001861
With Regards a
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Joe" <joebater@...> wrote:
>
> does anyone have any idea why discrepancies between E+ and simple steady state calculations, e.g. Q = U.A.dT, are so severe? despite it being a dynamic modelling approach you'd think that in the long term (e.g. a year) the two methods would have a reasonable harmony, instead I'm often finding 25-40% under-prediction in E+ compared to steady state for some simple buildings...
> is there a recommended report for building fabric heat losses?
> best regards and thanks in advance for any advice
> j.
>
__._,_.___
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
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 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.
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