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RE: [EnergyPlus_Support] Re: zone temperature





Please ignor this mail, if your problem has already been solved.
=============================
When looking at your detailed diagram, I notice that there is controller tied to three or four setpoint location, including the zone.  This may be the problem.
==============================
In general, reheat is for humidity control.   If you want individual zone temperature and humidity control, then you use a VAV Air terminal with reheat.  If you use a constant volume ATU with reheat, there is no advantage of individual control.
 
If you do not need humidity control, then the temperature defference between the cooling coil and the duct would provide some degree of moisture removal.  The control zone thermostat is used to control the AHU temperature, and all the other zones will share the air and will not have close temperature control.  Temperature of each zone is adjusted by the fractional flow rate at the ATU unconrolled (a damper).

The HW and CW set points are not related to the zone temperature directly,  therefore, it should not be tied to the zone thermostat.
 
============================
Almost every one that  I am replying to in this group mail has the problem of understanding the control zone for constant fan AHU operation and the individual zone thermostat control for each zone.
 
If the zone do not use a common AHU for zone heating and cooling, than it must have individual zone heating and cooling equipment, such as fan coils, and/or base-board heater/ radiators.  Each zone thermostat is used to control its own equipment.
 
If all the zone are fed from a common AHU and no other equipment in the zone.  One zone is selected as a master zone, and the themostat for that zone is used to control the air loop temperature.  The theremostat of the other zones are ignored.
 
If the common AHU is used to supply part of he zone load, such as fresh air only, then its output temperature has to be treated as a set point value.  The temperature is adjusted to the final desired value using some additional equipment such as a reheat heater in each zone.
 
Because a reheat unit cannot provide cooling, therefore, those using a low capacity AHU had problem of balancing the capacity with the demand for cooling, and ended up by using a four pipe fan coil unit in the zone, plus the common AHU.   The problem is now how to control the AHU using a setpoint manager.  The control zone thermostat is no longer available.
===============================
There are many setPointManagers.   I think, SetPointManager:MixedAir is one possible solution, if a cooling coil and a heatin coil is used with an OA mixer.
===========================
In your one zone system, removing the setpoint managers, and disabling the rehaet in the   air terminal may restore the thermostat control of the zone.  The thermostat is monitoring the air loop temperature.
 
 Dr. Li  



 

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: valeba23@xxxxxxxxx
Date: Wed, 8 Jun 2011 15:02:20 +0000
Subject: [EnergyPlus_Support] Re: zone temperature

 
thank,
but it is just my abbreviation for this message...into file is correct.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
>
>
> I am not sure whether the thermostat schedules are correct.
>
> ZoneControl:Thermostat,
> 3P:3ESP Thermostat, !- Name
> 3P:3ESP, !- Zone or ZoneList Name
> Zone Control Type Sched, !- Control Type Schedule Name
> ThermostatSetpoint:DualSetpoint, !- Control 1 Object Type
> Dual Setpoint - Zone 3P:3ESP; !- Control 1 Name
>
> ThermostatSetpoint:DualSetpoint,
> Dual Setpoint - Zone 3P:3ESP, !- Name
> 3P:3ESP Heating SP Sch, !- Heating Setpoint Temperature Schedule Name
> 3P:3ESP Cooling SP Sch; !- Cooling Setpoint Temperature Schedule
>
> 3P:3ESP Heating SP Sch, May-Jun-Jul-Aug-Sep Jan-Feb-Mar-Apr-Oct-Nov-Dec h9-20 22°C
> 3P:3ESP Cooling SP Sch May-Jun-Jul-Aug-Sep h9-20 24°C -- Jan-Feb-Mar-Apr-Oct-Nov-Dec h9-20 22°C
>
> I have not seen this format before.
>
> Dr. Li
>
>
>
>
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: valeba23@...
> Date: Tue, 7 Jun 2011 15:23:52 +0000
> Subject: [EnergyPlus_Support] zone temperature
>
>
>
>
>
>
> Why setpoint-temperatures are not maintained in the zone?
> The plant is into file : UTA
> The control is:
>
> Sizing:Zone,
> 3P:3ESP, !- Zone Name
> 16, !- Zone Cooling Design Supply Air Temperature {C}
> 35, !- Zone Heating Design Supply Air Temperature {C}
> 0.012, !- Zone Cooling Design Supply Air Humidity Ratio {kg-H2O/kg-air}
> 0.008, !- Zone Heating Design Supply Air Humidity Ratio {kg-H2O/kg-air}
> Flow/Person, !- Outdoor Air Method
> 0.00944, !- Outdoor Air Flow per Person {m3/s}
> , !- Outdoor Air Flow per Zone Floor Area {m3/s-m2}
> , !- Outdoor Air Flow per Zone {m3/s}
> , !- Zone Heating Sizing Factor
> , !- Zone Cooling Sizing Factor
> DesignDay, !- Cooling Design Air Flow Method
> , !- Cooling Design Air Flow Rate {m3/s}
> 0.000762, !- Cooling Minimum Air Flow per Zone Floor Area {m3/s-m2}
> , !- Cooling Minimum Air Flow {m3/s}
> , !- Cooling Minimum Air Flow Fraction
> DesignDay, !- Heating Design Air Flow Method
> , !- Heating Design Air Flow Rate {m3/s}
> 0.002032, !- Heating Maximum Air Flow per Zone Floor Area {m3/s-m2}
> 0.1415762, !- Heating Maximum Air Flow {m3/s}
> 0.3; !- Heating Maximum Air Flow Fraction
>
> Sizing:System,
> air_loop, !- AirLoop Name
> Sensible, !- Type of Load to Size On
> autosize, !- Design Outdoor Air Flow Rate {m3/s}
> 1, !- Minimum System Air Flow Ratio
> 35, !- Preheat Design Temperature {C}
> 0.008, !- Preheat Design Humidity Ratio {kg-H2O/kg-Air}
> 16, !- Precool Design Temperature {C}
> 0.012, !- Precool Design Humidity Ratio {kg-H2O/kg-Air}
> 16, !- Central Cooling Design Supply Air Temperature {C}
> 35, !- Central Heating Design Supply Air Temperature {C}
> NonCoincident, !- Sizing Option
> No, !- 100% Outdoor Air in Cooling
> No, !- 100% Outdoor Air in Heating
> 0.0012, !- Central Cooling Design Supply Air Humidity Ratio {kg-H2O/kg-Air}
> 0.008, !- Central Heating Design Supply Air Humidity Ratio {kg-H2O/kg-Air}
> DesignDay, !- Cooling Design Air Flow Method
> , !- Cooling Design Air Flow Rate {m3/s}
> DesignDay, !- Heating Design Air Flow Method
> ; !- Heating Design Air Flow Rate {m3/s}
>
> Sizing:Plant,
> chiller_plantloop, !- Plant or Condenser Loop Name
> Heating, !- Loop Type
> 5, !- Design Loop Exit Temperature {C}
> 7; !- Loop Design Temperature Difference {deltaC}
>
> Sizing:Plant,
> boiler_plantloop, !- Plant or Condenser Loop Name
> Heating, !- Loop Type
> 80, !- Design Loop Exit Temperature {C}
> 10; !- Loop Design Temperature Difference {deltaC}
>
> ZoneControl:Thermostat,
> 3P:3ESP Thermostat, !- Name
> 3P:3ESP, !- Zone or ZoneList Name
> Zone Control Type Sched, !- Control Type Schedule Name
> ThermostatSetpoint:DualSetpoint, !- Control 1 Object Type
> Dual Setpoint - Zone 3P:3ESP; !- Control 1 Name
>
> ThermostatSetpoint:DualSetpoint,
> Dual Setpoint - Zone 3P:3ESP, !- Name
> 3P:3ESP Heating SP Sch, !- Heating Setpoint Temperature Schedule Name
> 3P:3ESP Cooling SP Sch; !- Cooling Setpoint Temperature Schedule
>
> 3P:3ESP Heating SP Sch, May-Jun-Jul-Aug-Sep Jan-Feb-Mar-Apr-Oct-Nov-Dec h9-20 22°C
> 3P:3ESP Cooling SP Sch May-Jun-Jul-Aug-Sep h9-20 24°C -- Jan-Feb-Mar-Apr-Oct-Nov-Dec h9-20 22°C
>
> SetpointManager:SingleZone:Heating,
> setpoint_heating, !- Name
> Temperature, !- Control Variable
> 0, !- Minimum Supply Air Temperature {C}
> 99, !- Maximum Supply Air Temperature {C}
> 3P:3ESP, !- Control Zone Name
> Node PLF:PLFZ Zone, !- Zone Node Name
> 3P:3ESP Inlets, !- Zone Inlet Node Name
> 3esp_coil_heating_air_outlet_node; !- Setpoint Node or NodeList Name
>
> SetpointManager:SingleZone:Cooling,
> setpoint_cooling, !- Name
> Temperature, !- Control Variable
> 0, !- Minimum Supply Air Temperature {C}
> 40, !- Maximum Supply Air Temperature {C}
> 3P:3ESP, !- Control Zone Name
> Node PLF:PLFZ Zone, !- Zone Node Name
> 3P:3ESP Inlets, !- Zone Inlet Node Name
> 3esp_coil_heating_air_outlet_node; !- Setpoint Node or NodeList Name
>
> SetpointManager:Scheduled,
> CW_supply_Temp_SP_schedule, !- Name
> Temperature, !- Control Variable
> CW_supply_Temp_Setpoint, !- Schedule Name
> CW_supply_outlet_node; !- Setpoint Node or NodeList Name
>
> Schedule:Compact,
> CW_supply_Temp_Setpoint, !- Name
> Temperature, !- Schedule Type Limits Name
> through:12/31, !- Field 1
> for:alldays, !- Field 2
> until:24:00, 7; !- Field 4
>
> SetpointManager:Scheduled,
> HW_supply_Temp_SP_schedule, !- Name
> Temperature, !- Control Variable
> HW_supply_Temp_Setpoint, !- Schedule Name
> HW_supply_outlet_node; !- Setpoint Node or NodeList Name
>
> Schedule:Compact,
> HW_supply_Temp_Setpoint, !- Name
> Temperature, !- Schedule Type Limits Name
> through:12/31, !- Field 1
> for:alldays, !- Field 2
> until:24:00, 70; !- Field 4
>
> thank,
> valeria
>




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