I think some one did that a few years back.
You need to be on the equator, no solar radiation or all values the same for the day and night, no surface ground variation, no deep ground variation, equinox date, etc.
Since you have a yearly cycle, the response may not reach the steady state, and approaches an exponential up and an exponential down curve on multi-year run.
You may try it on the DesignDay simulation also. ODT can be two steps, one up and one down, entered as a schedule. Skycleance can be zero. The response will still be rounded square wave, or triangular wave. Some of exponentials can never have zero delay.
The delay is in the material and construction, depending on the heat conductance, specific heat and mass or volume.
The ground cooling is always there. Therefore, the pyramid is a good green building design.
The roof radiates to the sky temperature at night, which is few degree below the ODT.
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: energyplus_problem@xxxxxxxxx
Date: Mon, 18 Apr 2011 13:35:34 +0000
Subject: [EnergyPlus_Support] Re: Step response of model
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Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: energyplus_problem@xxxxxxxxx
Date: Mon, 18 Apr 2011 13:35:34 +0000
Subject: [EnergyPlus_Support] Re: Step response of model
We want to investigate exactly this lagging and especially the time needed to reach the ODT (probably several weeks). The question is why it doesn't reach the ODT while holding it constant, but arrives asymptotically on a much lower temperature, without any cooling.
So what we did was creating a - lets say - one year weather file with a temperature step in march to december and an according ground temperature.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
>
>
> I do not know why you wanted to do a step response test, and I am not sure how you are applying the values.
> The weather file data is in one hour steps, and interpolated during simulation. A step applied using the weather file may not produce a step in simulation..
> The indoor temperature is usually lagging the ODT because of the surface convection/conduction delay, thermo-mass calculation delay and floor ground cooling.
>
> Dr. Li
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: energyplus_problem@...
> Date: Mon, 18 Apr 2011 09:48:04 +0000
> Subject: [EnergyPlus_Support] Step response of model
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> Hello everyone
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> We now have successfully modelled a two story house with basement and are now trying to get a step response out of it. What we did is we have produced a weather file that suddenly changes from 0 to a higher temperature (ground temperature as well) with all other variables equal to zero and have our building simulated with it. There is no AC in our house, but the response shows that the house will never reach the outdoor temperature, but stays steady some degrees below it. For example, if the step is from 0 to 50 degrees celsius, the mean temperature within the house stays at around 44 degrees.
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> Does someone have an explanation for this phenomena? Maybe because the algorithms (DOE-2 outdoors and TARP inside) are not fitted for such a theoretical problem?
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> Thanks, Jan
>
So what we did was creating a - lets say - one year weather file with a temperature step in march to december and an according ground temperature.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
>
>
> I do not know why you wanted to do a step response test, and I am not sure how you are applying the values.
> The weather file data is in one hour steps, and interpolated during simulation. A step applied using the weather file may not produce a step in simulation..
> The indoor temperature is usually lagging the ODT because of the surface convection/conduction delay, thermo-mass calculation delay and floor ground cooling.
>
> Dr. Li
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: energyplus_problem@...
> Date: Mon, 18 Apr 2011 09:48:04 +0000
> Subject: [EnergyPlus_Support] Step response of model
>
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>
>
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>
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>
>
> Hello everyone
>
>
>
> We now have successfully modelled a two story house with basement and are now trying to get a step response out of it. What we did is we have produced a weather file that suddenly changes from 0 to a higher temperature (ground temperature as well) with all other variables equal to zero and have our building simulated with it. There is no AC in our house, but the response shows that the house will never reach the outdoor temperature, but stays steady some degrees below it. For example, if the step is from 0 to 50 degrees celsius, the mean temperature within the house stays at around 44 degrees.
>
>
>
> Does someone have an explanation for this phenomena? Maybe because the algorithms (DOE-2 outdoors and TARP inside) are not fitted for such a theoretical problem?
>
>
>
> Thanks, Jan
>
__._,_.___
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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