Re: [EnergyPlus_Support] Re: Time Setpoint Not Met and Zone Multiplier

[Linda Lawrie <linda@xxxxxxxxxxxxxx>]

The autosize should have done that -- if you think not,
please submit your file to the helpdesk.

At 08:29 AM 3/1/2012, Carolina Galeazzi wrote:

Hi Linda,
I am autosizing all equipments, and all zones have similar hours not met,  around 300 hours in total.  But if I multiply my middle floors, I get around 3000 hours in total, but the numbers of hours are increased only for those multiplied zones. Should I also multiply the middle floor air handling unit by 8 somehow?
 
Thank you
Carolina
De: Linda Lawrie <linda@xxxxxxxxxxxxxx>
Para: EnergyPlus_Support@xxxxxxxxxxxxxxx
Enviadas: Quinta-feira, 1 de Março de 2012 10:53
Assunto: Re: [EnergyPlus_Support] Re: Time Setpoint Not Met and Zone Multiplier

 
Autosize should take care of any of those system or plant fields -- however, if you have any hard sized fields mixed in you will need to multiply them.

From the Tips & Tricks document:

Guidelines for Using Multipliers and Groups

•  If the basic zone geometry is identical, make one zone, copy & paste it as necessary, then change the Zone Origin field to locate each zone correctly.
•  Do not use interzone surfaces between zones that are multiplied. Set the adjoining surfaces to be adiabatic, i.e. use the OtherZoneSurface exterior boundary condition with the other surface pointing back to itself.
•  Locate the middle floor zones roughly halfway between top and ground because exterior convection coefficients change with height. Halfway should cause the differences to average out. If you have many stories (the example only has 10 stories), consider using more middle floor zones.
•  Consider removing the effects of height variation for the simulation.
•  Follow guidelines in HVACTemplate and other objects about sizing if you are mixing autosize fields with hard sized fields (recommended to â??autosizeâ?? all fields rather than mix).

At 06:41 AM 3/1/2012, Carolina Galeazzi wrote:

Hi Mario,
Thank you for your answer.
According to the IOR, I have to multiply by 8 the capacity of my system to meet the entire multiplied zone?
Energyplus autosizing wouldn't do that by itself?
I didn't understand your question about the filed restricted, what do you mean?
 
Regards,
Carolina
De: MÃ?Æ?Ã?¡rio <mneves32@xxxxxxxxx>
Para: EnergyPlus_Support@xxxxxxxxxxxxxxx
Enviadas: Quinta-feira, 1 de Mar�§o de 2012 8:29
Assunto: [EnergyPlus_Support] Re: Time Setpoint Not Met and Zone Multiplier

 
Hello,

Acording to the IOR:

"Field: Multiplier
Zone Multiplier is designed as a "multiplier" for zone loads. It takes the calculated load for the
inputted zone and multiplies it and sends the multiplied load to the attached system to meet
the demand. The system will have to be specified to meet the entire multiplied zone load and
will report the amount of the load it can meet in the Zone/Sys Sensible Heating or Cooling
Energy/Rate report variable. The default is 1."

So are you sure you don�´t have any individual, field restricted to responde only to a single zone?

MN

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Carolina Galeazzi <caro_poa@...> wrote:
>
> Dear All,
> Ã?? I am simulating
> an existing building, with 14 floors in total but 8 of them are identical
> floors. For these, I have modeled one typical floor and used a multiplier of 8 in each zone to represent
> all floors. However, I was having huge time setpoint not met (I am autosizing
> all capacities and flow rates). I simulated the building again without the
> multiplier, this has decreased the setpoint to below 300 unmet hours, as it
> should be regarding ASHRAE 90.1.
> Ã?? Please
> correct me if I am wrong, but I understand that only the zones were multiplied,
> not the AHU that I have for each floor, because the multiplier was defined
> within the zone.
> Ã?? My question
> is: Is there a way that I could use the multiplier also for the AHUs that are
> connected to these multiplied zones, to have a correct result of total load? Or
> should I not use multiplier and multiply the load of the typical floors by 8 �¢??by
> hand�¢?? (not sure if this is acceptable thothough)?<)?
> Thank you in
> advance for your feedback and suggestions,
> Carolina
>

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