Re: [EnergyPlus_Support] Space heating demand. HELP

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2017-08-03 0:52 GMT+02:00 Giuseppina Buttitta giusybuttitta@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:

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Thanks,

I attached here the graph where it is possible to see the heating demand and the temperature set point.
In one graph the data for the design winter day are reported, while the other graph shows the data for the operational period.

Thanks,
GiusiÂ
On Wednesday, August 2, 2017 10:43 PM, "Julien MARREC julien.marrec@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@yahoogroups.com> wrote:
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Please add an output variable for "schedule value" with a key set to your schedule name (eg: "heating sp" or whatever it is) and plot that on the same graph.

That'll help to determine the issue.

EnvoyÃ© de mon iPhone

Le 2 aoÃ»t 2017 Ã 21:17, "Giuseppina Buttitta giusybuttitta@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@yahoogroups.com> a Ã©critÂ :
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Thank you for your reply,

I guess it is normal for the heating system to have a peak upon startup, however I think that the peak is too large and the reason is that the heating system is not correctly dimensionated.
Please find attached the temperature schedules used in the design day and in the normal operational days. I also attached the resulting "meter file".Â
I also tried to increse the setback smoothly for regular days, but it doesn't change the magnitude of the peak demand.

Thanks again for your help.

All the best,
Giusi
On Wednesday, August 2, 2017 7:12 PM, "Jim Dirkes jim@buildingperformanceteam.com [EnergyPlus_Support]" <EnergyPlus_Support@yahoogroups.com> wrote:
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As I think about this....
Why is it a problem for the heating system to have a large peak upon startup? It seems that is exactly what occurs when the heating system starts and begins to transition the building from an unoccupied period with lower setpoint to an occupied period (and higher setpoint).
On Wed, Aug 2, 2017 at 6:43 AM, Giuseppina Buttitta giusybuttitta@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@yahoogroups.com> wrote:

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Thank you all for the reply,

I used your suggestions and I applied a schedule with a constant temperature as heating schedule of the design day. Peaks now are significantly reduced, however they are still there (see attached figure).
Do you have any idea about other possible causes? I also considered the heating sizing factor equal to 1.

Thanks again,
Giusi

On Tuesday, August 1, 2017 6:11 PM, "Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@ yahoogroups.com> wrote:

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Your autosizing settings will determine how large the equipment is depending on how fast they have to bring the zone to the required setpoint after they are turned on. Either ramp the setpoint or increase the pulldown time in the autosizing options.

Am 31.07.2017 2:34 nachm. schrieb "Giuseppina Buttitta giusybuttitta@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@ yahoogroups.com>:

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Hi all!
I have tried to model the energy consumption for heating of a dwelling heated by electric baseboards. All the installed electric baseboards are controlled by a thermostat.
However, the results I obtained look weird to me.
The heating energy request is not constant during the period but it has a really big peak when the heaters are turnud on and then the request is quite small during the rest of the day (see attached picture). It looks like the heaters are oversized for the dwellings.
I tried to check again my code several times but everything seems fine.
Do you have any idea what the problem could be?

I know it is a vague request, but probably it has already happened to some of you.

Thanks,
Giusi

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