Mr.Ooi's reasoning was correct.
What you should do notmally is to plot the weather file ODT and have a look at the shape of the curve.
Roof temperature is mainly due to radiation. You should display the solar radiation input as well.
The zone mean air temperature, and any temperature value of interested should be plotted on the same chart if possible.
Attached is a daily plot of the solar conditions at Golden Solar Radiation Reeasch Lab. When you sample such a wave form, you can get large difference in sampled values at one hour interval. If you do get such a chart from Changi Airport, what are you going to do with it. They can be made available.
Without knowing what is your input file and what variable you are looking at, ti is very difficult to tell.
Because the input values are in one hour steps, increasing the timestop to 60 will not give you more accurate results.
You will soon find out that the interpolation on the spread sheet is just as good. 4 timestep is the recomended defult. I generally use 6 timestep to give a 10 minuite interval for results. There are certain special cases which requires a higher number of timesteps to help convergence with a few timesteps.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: fypguevibyor@xxxxxxxxx
Date: Sun, 1 Apr 2012 12:26:26 +0000
Subject: [EnergyPlus_Support] Re: Sudden temperature drops and ups
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Primary EnergyPlus support is found at:
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The primary EnergyPlus web site is found at:
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What you should do notmally is to plot the weather file ODT and have a look at the shape of the curve.
Roof temperature is mainly due to radiation. You should display the solar radiation input as well.
The zone mean air temperature, and any temperature value of interested should be plotted on the same chart if possible.
Attached is a daily plot of the solar conditions at Golden Solar Radiation Reeasch Lab. When you sample such a wave form, you can get large difference in sampled values at one hour interval. If you do get such a chart from Changi Airport, what are you going to do with it. They can be made available.
Without knowing what is your input file and what variable you are looking at, ti is very difficult to tell.
Because the input values are in one hour steps, increasing the timestop to 60 will not give you more accurate results.
You will soon find out that the interpolation on the spread sheet is just as good. 4 timestep is the recomended defult. I generally use 6 timestep to give a 10 minuite interval for results. There are certain special cases which requires a higher number of timesteps to help convergence with a few timesteps.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: fypguevibyor@xxxxxxxxx
Date: Sun, 1 Apr 2012 12:26:26 +0000
Subject: [EnergyPlus_Support] Re: Sudden temperature drops and ups
Hi Ooi,
Thank you for your answer. I tried to use "no" in "use weather file rain and snow indicator" but the abrupt ups and downs still persist.
I really don't have any idea to solve this.
Regards,
Malindo
Final year student
Singapore
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ooi" <ooi_kb3@...> wrote:
>
> The sudden ups and downs are most probably due to rain, if in your SimulationControl object, the 'Run Simulation for Weather File periods' has been set to Yes, Check and see if rain is indicated in the weather file, at the sudden 'downs'
>
> The 'downs' can also occur if in the SimulationControl object, the 'Run Simulation for Sizing periods' has been set to Yes, and the Rain Indicator field has been set to 1.
>
> ooi
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "malindow" <fypguevibyor@> wrote:
> >
> > Dear all,
> >
> > I make a building model (simple box). I run a simulation and got roof temperature profile during 1 week period. There are a lot of sudden ups and downs (like zig-zag) in the temperature profile.
> >
> > Anyone has suggestion how I can get a smoother temperature profile?
> > I have tried a lot of things but I still can't get it.
> >
> > Thanks in advance.
> >
> > Regards,
> >
> > Malindo
> > Mech. Engineering student
> > Singapore
> >
>
Thank you for your answer. I tried to use "no" in "use weather file rain and snow indicator" but the abrupt ups and downs still persist.
I really don't have any idea to solve this.
Regards,
Malindo
Final year student
Singapore
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ooi" <ooi_kb3@...> wrote:
>
> The sudden ups and downs are most probably due to rain, if in your SimulationControl object, the 'Run Simulation for Weather File periods' has been set to Yes, Check and see if rain is indicated in the weather file, at the sudden 'downs'
>
> The 'downs' can also occur if in the SimulationControl object, the 'Run Simulation for Sizing periods' has been set to Yes, and the Rain Indicator field has been set to 1.
>
> ooi
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "malindow" <fypguevibyor@> wrote:
> >
> > Dear all,
> >
> > I make a building model (simple box). I run a simulation and got roof temperature profile during 1 week period. There are a lot of sudden ups and downs (like zig-zag) in the temperature profile.
> >
> > Anyone has suggestion how I can get a smoother temperature profile?
> > I have tried a lot of things but I still can't get it.
> >
> > Thanks in advance.
> >
> > Regards,
> >
> > Malindo
> > Mech. Engineering student
> > Singapore
> >
>
__._,_.___
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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