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RE: [EnergyPlus_Support] Re: Night Ventilation



I did attach my idf file - If you have a chance to look at it, that would be appreciated.

I don't see the connection from ZoneVentilation:DesignFlowRate to "monitoring the outdoor and indoor temperature difference".  This object has parameters for "Minimum Indoor Temperature" and  " Delta Temperature", which should define  allow or disallow ventilation. Or do I need to reference outside air temperature somewhere?  BTW, I checked with  what the sample 5ZZoneNightVent2.idf file uses as parameters.

Thanks





----- Original Message -----
From: "YuanLu Li" <yli006@xxxxxxxxxxx>
Sent: Wed, August 11, 2010 16:18
Subject: RE: [EnergyPlus_Support] Re: Night Ventilation

 

I normally do not respond to questions without the IDF posted at the same time. 
 
I still cannot tell from your descriptin how the schedules are applied.
 
Night cooling with outside air is not always possible with non-integrated control, i.e., without monitoring the outdoor and indoor air temperature difference.
======================================
IF ((IndoorTemp - OutdoorTemp) < DeltaTemperature) Then ventilation is not allowed.
 
The above condition is applied in the following object.
================================
ZoneVentilation:DesignFlowRate,
SPACE1-1 Ventl 1, !- Name
SPACE1-1, !- Zone Name
NightVentSched, !- SCHEDULE Name
Flow/Zone, !- Design Volume Flow Rate calculation method
.05295, !- Design Volume Flow Rate {m3/s}
, !- Volume Flow Rate per area {m3/s/m2}
, !- Volume Flow Rate per person {m3/s/person}
, !- Air Changes Per Hour
Intake, !- Ventilation Type
67., !- Fan Pressure Rise
.7, !- Fan Total Efficiency
1, !- Constant Term Coefficient
0, !- Temperature Term Coefficient
0, !- Velocity Term Coefficient
0, !- Velocity Squared Term Coefficient
, !- Minimum Indoor Temperature {C}
MinIndoorTemp, !- Minimum Indoor Temperature Schedule Name
, !- Maximum Indoor Temperature {C}
MaxIndoorTemp, !- Maximum Indoor Temperature Schedule Name
, !- Delta Temperature {deltaC}
DeltaTemp, !- Delta Temperature Schedule Name
, !- Minimum Outdoor Temperature {C}
MinOutdoorTemp, !- Minimum Outdoor Temperature Schedule Name
, !- Maximum Outdoor Temperature {C}
MaxOutdoorTemp, !- Maximum Outdoor Temperature Schedule Name
40; !- Maximum WindSpeed {m/s}
 
The example has a NightVenSched, but it may not be the one you are looking for.  I do not know how you impemented all the schedules and integrated them with the Zone HVAC system..
 
If you have a night schedule, you can list it in the .csv spread sheet  using the:
 
Output:Variable, *, Schedule Value,  hourly;    (or timestep; )
 
which will list the vales of all the schedules.
 
This object do not have a fan object specified, and therefore may not have a separate  item listed in the report.  The power is probably calculated using the values in this object.  The object is used to calculate the design flowrate and then modify it with schedules.
 
If the power is calculated and listed in the .csv file, you can request monthly and annual values on the spread sheet.   The name of the variables are in the .rdd file after runnng the simulation.
 
This is only one object in the IDF.  It can be over ridden by other schedules in the IDF.
 
In order to use your fan in this way, you will need at least two thermometers/thermostats and a controller.
If your fan is not a variable speed one, you will need a bypass path and a damper to control the flow.  These functions are in the outside air mixer box object.  That was the reason why I suggested the UnitVentilator model.
 

 Dr. Li  



 
To: EnergyPlus_Support@yahoogroups.com
From: neil@airscapefans.com
Date: Wed, 11 Aug 2010 17:17:29 +0000
Subject: [EnergyPlus_Support] Re: Night Ventilation

 
Thanks for the response.
Yes, 'night ventilation' is not specific.
What I want to model is using 'whole house fan' for residential applications. (this is what we manufacture: www.airscapefans.com)

This model does not have to be very complex. For the first pass I used the on-line generated basic building model, and then added 'ZoneVentilation: DesignFlowRate' with what I think are logical parameters. I control this ventilation on a seasonal schedule, and then also modified the heating setpoints seasonally to make sure that no summer heating is taking place.
My results are basically the same as the control house without night cooling.
Also, I do not see this extra night ventilation fan show up in the fan kw report - Any clues here as to where I might investigate ?
-Neil

--- In EnergyPlus_Support@yahoogroups.com, YuanLu Li <yli006@...> wrote:
>
>
> I did not suggest a full working example, because night venitlation is too general as a requirement.
>
>
>
> Building with natural ventilation will be using AFN.
>
>
>
> Building with HVAC will be using economizer control in the system with a night schedule.
>
>
>
> Adaptive control need to integrate the control with the weather, i.e., difference in temperature and humidity between the outdoor and indoor conditions, and time, at night times only.
>
>
>
> The UnitVentilator model has the economizer and OA controller, and was therefore the first to try by a beginner as a complete system.
>
>
>
> When you have master the schedules and the controller and manager, then you can improve the complexity to match your night time requirements.
>
>
>
> It is not simple, and there is no general answer.
>
>
>
> If you just want to turn on some ventilation at night at a specific time, it is easy. Use a ventilation object and a schedule.
>
>
>
> If you wanted it to be adaptive, it is not so simple. I know some research students are working on it, but I am not directly involved.
>
>
>
> Dr. Li
>
>
>
>
> To: EnergyPlus_Support@yahoogroups.com
> From: neil@...
> Date: Wed, 11 Aug 2010 05:01:19 +0000
> Subject: [EnergyPlus_Support] Re: Night Ventilation
>
>
>
>
>
>
> First of all, I'd like to know if Matt did find a solution.
>
> Next, could someone give a detailed response as to how to model night free cooling. There seem to be conflicting (half) methods around.
> - separate air handler?
> - ZoneAirflow: ZoneVentilationDesignRate ?
> - SystemAvailabilityManager: AvailabilityManager: NightVentilation?
>
> I tried #2 (seemed logical), but my results do not seem credible.
>
> I would appreciate if the instructions were somewhat more detailed than "try X".
>
> Thank You
>
> --- In EnergyPlus_Support@yahoogroups.com, YuanLu Li <yli006@> wrote:
> >
> >
> > Try the UnitVentilator model, using the minimum amount of cooling for the day time and the outdoor air ventilation as economizer.
> >
> >
> >
> > The outdoor temperature is monotored to control the amount of air flow into the OA mixer inlet node
> >
> >
> >
> > Dr. Li
> >
> >
> >
> >
> > To: EnergyPlus_Support@yahoogroups.com
> > From: liambrn@
> > Date: Mon, 19 Apr 2010 23:00:37 +0000
> > Subject: [EnergyPlus_Support] Re: Night Ventilation
> >
> >
> >
> >
> >
> > Matt,
> >
> > As a means to estimate effectiveness of nighttime ventilation, you could create a ZoneVentilation object that only comes on at the appropriate time (night, summer, etc.) using a schedule and when the outdoor temperature is within a certain range. The limitation to this is that you'll need to carefully choose the range of dates so that ventilation doesn't cause unecessary daytime heating.
> > Hope that helps...
> >
> > Liam O'Brien
> >
> > --- In EnergyPlus_Support@yahoogroups.com, "Matt Fung" <mfung@> wrote:
> > >
> > > Hello EnergyPlus Users,
> > >
> > >
> > >
> > > I was wondering if anyone had any tips or examples as to how to model
> > > night ventilation in a residential home. Any help would be greatly
> > > appreciated. Thanks.
> > >
> > >
> > >
> > > Matt Fung, P.E.
> > >
> > > Research Engineer
> > >
> > > <http://www.consol.ws/>
> > >
> > > 7407 Tam O'Shanter Drive
> > >
> > > Stockton, CA 95210-3370
> > >
> > > Phone: 209.473.5000 / Fax: 209.474.0817
> > >
> > > MFung@ <mailto:MFung@>
> > >
> > > www.ConSol.ws <http://www.consol.ws/>
> > >
> > >
> > >
> > > You can call me directly at 209.473.5002
> > >
> > >
> > >
> > > ConSol leads the Building Industry Research Alliance (BIRA) for the
> > > Department of Energy.
> > >
> > > To learn more about next generation homes and communities, visit
> > > www.BIRA.ws <http://www.bira.ws/>
> > >
> >
> >
> >
> >
> >
> > __________________________________________________________
> > Videos that have everyone talking! Now also in HD!
> > http://go.microsoft.com/?linkid=9724465
> >
>

 
 

 



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Attachment not found:
d:\eudora\attach\basichouse-whf.idf