I have high lighted the two lines below. There are many ways to stop the ventilation operation in Winter.
If you look at the outdoor dry-bulb temperature in the listing, the value in Winter sometimes exceeds 15°C. At those hours, the ventilation will come on.
If you set it too high, the ventilation will start too late in Summer, or do not start at all.
Therefore, you can modify the WHF schedule, using say 21°C for Winter, and 18°C for Summer, and place the name in the schedule field. You may also simply try 20°C all the year round.
For the normal economizer operation, the OA mixer can reduce the air flow as well, uing schedules on temperature differences.
You can put back the WHF schedule as is, in the "Always_On" field, to stop the operation in Winter. This schedule is actually a multiplier type. This did not work before, because you set the max. indoor temperature to -17°C. I set it to 26, because the zone is air conditioned to 24°C.
=======================
The object has no schedule at present. The on and off of the ventilation depends on the temperature between the zone and outdoor air, when the difference is less than 2°C, the ventilation stops. (See the equation in an earlier mail or IO manual.)
If the output variable is displayed in timesteps instead of hourly, you will see the air flow volume more constant, because the output value is the averaged hourly value. Starting and stopping time of the ventilation did not line up exactly at the hour mark. The fan is constant volume as set in the object to get the ACH value as shown in the .csv.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: neil@xxxxxxxxxxxxxxxx
Date: Sat, 14 Aug 2010 22:05:40 +0000
Subject: [EnergyPlus_Support] Progress! Night Ventilation
OK, You have got me out of the stupid error category. Thank You.
The fan in question seems to be modulating its airflow - What schedule governs this ?
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
>
>
> By turning on the object all the time, you will see some output in the table. The values you have entered caused the object to stop working. I have the object aloways_ON and and changed some min and max values.
>
> Now that you can see some values in the .csv file, you can fine tune the schedules to get what you want.
>
> ZoneVentilation:DesignFlowRate,
> whole house fan, !- Name
> ZN_1_FLR_1_SEC_1, !- Zone Name
> Always_On, !- Schedule Name **8 Changed WHF ** (This can be used to modiffy the designed flow rate.)
> Flow/Zone, !- Design Flow Rate Calculation Method
> 1.18000014980471, !- Design Flow Rate {m3/s}
> , !- Flow Rate per Zone Floor Area {m3/s-m2}
> , !- Flow Rate per Person {m3/s-person}
> , !- Air Changes per Hour
> Exhaust, !- Ventilation Type
> 100, !- Fan Pressure Rise {Pa}
> 0.75, !- Fan Total Efficiency
> 1, !- Constant Term Coefficient
> 0, !- Temperature Term Coefficient
> 0, !- Velocity Term Coefficient
> 0, !- Velocity Squared Term Coefficient
> 18.8888893892736, !- Minimum Indoor Temperature {C}
> , !- Minimum Indoor Temperature Schedule Name
> 26,
> ! -17.7777782487281, !- Maximum Indoor Temperature {C} (This condition cannot be met in Summer.)
> , !- Maximum Indoor Temperature Schedule Name
> 2, !- Delta Temperature {deltaC}
> , !- Delta Temperature Schedule Name
> 15, !- Minimum Outdoor Temperature {C}
> WHF, !- Minimum Outdoor Temperature Schedule Name
> 22.0000005298191, !- Maximum Outdoor Temperature {C}
> , !- Maximum Outdoor Temperature Schedule Name
> 40; !- Maximum Wind Speed {m/s}
>
>
> ==================
>
> Output:Variable,*,Zone Ventilation Air Change Rate,hourly; !- HVAC Average [ach]
> Output:Variable,*,Zone Ventilation Fan Electric Consumption,hourly; !- HVAC Sum [J]
>
>
>
>
> Add these two lines to see when the fan is operating.
>
>
>
> By changing the minimum outdoor to a higher value in Winter and lower value in Summer as a schedule, to over ride the 15°C number, you will probably get what you wanted to do.
>
>
> If you are going to open window, etc, you need to study the Air Flow Network examples. This object give you an equivalent to an opening window, without a window in the zone. The energy usage is listed under the ventilation fan (simple) and will depend on the constants youhave entered in the object.
>
>
> Dr. Li
>
>
>
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: neil@...
> Date: Fri, 13 Aug 2010 14:46:40 +0000
> Subject: [EnergyPlus_Support] Re: Night Ventilation
>
>
>
>
>
>
> I'm still missing something basic:
>
> When I defined the object within ZoneVentilation:DesignFlowRate I included parameters to describe a fan, including fan static pressure, efficiency, etc.
>
> In reality, this nighttime exhaust fan is a separate piece of equipment. Makeup air would be brought in by opening windows.
>
> So, yes, I don't understand how to model this. I do need more detailed guidance, please. I have combed through the example file :
> 5ZoneNightVent2.idf and it seems like that model uses the same basic idea - ZoneVentilation:DesignFlowRate objects are populated.
>
> Thanks.
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@> wrote:
> >
> >
> > I had a quick look at your IDF and ran one simulaation.
> >
> >
> >
> > You have a heating coil, a cooling coil, and a constant volume fan in the air loop. There is no outside air intake, or mixer.
> >
> >
> >
> > The WHF schedule is set, but there is nothing to control.
> >
> >
> >
> > I do not know how much guidance you need to fix the problems.
> >
> >
> >
> > The nearest example for you is to use the outside air intake in the economy cycle, which has an outside air mixer in the air loop. Depending on the temperature difference, the amount of outside air is varied.
> >
> >
> >
> > If you wanted to use the fan as a separate component, it may be possible. The difference in temperature which is set in the design flow rate object is that between the zone and the outdoor air in the weather file. The ventilation is turned on, and hope that the injected air will change the cooling rate at the coil. It can work in Winter during the day time as well, when the OA is warmer than the setpoint..
> >
> >
> > So let me know what you can change and I will try to answer your questions.
> >
> >
> >
> > I have turned on the diagnostics to see all the warnings and unused objects and schedules. There are many warnings, but the simulation was meaningful on all the working parts..
> >
> >
> > Dr. Li
> >
> >
> >
> >
> >
> >
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > From: neil@
> > Date: Thu, 12 Aug 2010 01:33:51 -0500
> > Subject: 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 ----- Deleted.
> >
>
The fan in question seems to be modulating its airflow - What schedule governs this ?
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
>
>
> By turning on the object all the time, you will see some output in the table. The values you have entered caused the object to stop working. I have the object aloways_ON and and changed some min and max values.
>
> Now that you can see some values in the .csv file, you can fine tune the schedules to get what you want.
>
> ZoneVentilation:DesignFlowRate,
> whole house fan, !- Name
> ZN_1_FLR_1_SEC_1, !- Zone Name
> Always_On, !- Schedule Name **8 Changed WHF ** (This can be used to modiffy the designed flow rate.)
> Flow/Zone, !- Design Flow Rate Calculation Method
> 1.18000014980471, !- Design Flow Rate {m3/s}
> , !- Flow Rate per Zone Floor Area {m3/s-m2}
> , !- Flow Rate per Person {m3/s-person}
> , !- Air Changes per Hour
> Exhaust, !- Ventilation Type
> 100, !- Fan Pressure Rise {Pa}
> 0.75, !- Fan Total Efficiency
> 1, !- Constant Term Coefficient
> 0, !- Temperature Term Coefficient
> 0, !- Velocity Term Coefficient
> 0, !- Velocity Squared Term Coefficient
> 18.8888893892736, !- Minimum Indoor Temperature {C}
> , !- Minimum Indoor Temperature Schedule Name
> 26,
> ! -17.7777782487281, !- Maximum Indoor Temperature {C} (This condition cannot be met in Summer.)
> , !- Maximum Indoor Temperature Schedule Name
> 2, !- Delta Temperature {deltaC}
> , !- Delta Temperature Schedule Name
> 15, !- Minimum Outdoor Temperature {C}
> WHF, !- Minimum Outdoor Temperature Schedule Name
> 22.0000005298191, !- Maximum Outdoor Temperature {C}
> , !- Maximum Outdoor Temperature Schedule Name
> 40; !- Maximum Wind Speed {m/s}
>
>
> ==================
>
> Output:Variable,*,Zone Ventilation Air Change Rate,hourly; !- HVAC Average [ach]
> Output:Variable,*,Zone Ventilation Fan Electric Consumption,hourly; !- HVAC Sum [J]
>
>
>
>
> Add these two lines to see when the fan is operating.
>
>
>
> By changing the minimum outdoor to a higher value in Winter and lower value in Summer as a schedule, to over ride the 15°C number, you will probably get what you wanted to do.
>
>
> If you are going to open window, etc, you need to study the Air Flow Network examples. This object give you an equivalent to an opening window, without a window in the zone. The energy usage is listed under the ventilation fan (simple) and will depend on the constants youhave entered in the object.
>
>
> Dr. Li
>
>
>
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: neil@...
> Date: Fri, 13 Aug 2010 14:46:40 +0000
> Subject: [EnergyPlus_Support] Re: Night Ventilation
>
>
>
>
>
>
> I'm still missing something basic:
>
> When I defined the object within ZoneVentilation:DesignFlowRate I included parameters to describe a fan, including fan static pressure, efficiency, etc.
>
> In reality, this nighttime exhaust fan is a separate piece of equipment. Makeup air would be brought in by opening windows.
>
> So, yes, I don't understand how to model this. I do need more detailed guidance, please. I have combed through the example file :
> 5ZoneNightVent2.idf and it seems like that model uses the same basic idea - ZoneVentilation:DesignFlowRate objects are populated.
>
> Thanks.
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@> wrote:
> >
> >
> > I had a quick look at your IDF and ran one simulaation.
> >
> >
> >
> > You have a heating coil, a cooling coil, and a constant volume fan in the air loop. There is no outside air intake, or mixer.
> >
> >
> >
> > The WHF schedule is set, but there is nothing to control.
> >
> >
> >
> > I do not know how much guidance you need to fix the problems.
> >
> >
> >
> > The nearest example for you is to use the outside air intake in the economy cycle, which has an outside air mixer in the air loop. Depending on the temperature difference, the amount of outside air is varied.
> >
> >
> >
> > If you wanted to use the fan as a separate component, it may be possible. The difference in temperature which is set in the design flow rate object is that between the zone and the outdoor air in the weather file. The ventilation is turned on, and hope that the injected air will change the cooling rate at the coil. It can work in Winter during the day time as well, when the OA is warmer than the setpoint..
> >
> >
> > So let me know what you can change and I will try to answer your questions.
> >
> >
> >
> > I have turned on the diagnostics to see all the warnings and unused objects and schedules. There are many warnings, but the simulation was meaningful on all the working parts..
> >
> >
> > Dr. Li
> >
> >
> >
> >
> >
> >
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > From: neil@
> > Date: Thu, 12 Aug 2010 01:33:51 -0500
> > Subject: 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 ----- Deleted.
> >
>
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