It may also be radiating heat to the night sky, its effective temperature is cooler than outdoor drybulb.
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of energyplus_problem
Sent: Monday, April 18, 2011 7:36 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
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:
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> 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.
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> Dr. Li
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> 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
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