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Re: [EnergyPlus_Support] Re: EvapCooler in exhaust stream





There are 4 air streams on an OA mixer ... the outdoor, exhaust, return, and mixed air. The return is connected to the combined zone air mixer outlet. The mixed air is connected to the air loop supply going to the zones.  These 2 air steams are not considered part of the outdoor air system.

The other 2 air streams, the outdoor and exhaust, and any equipment in one or both air streams, makes up the outdoor air system. Yes, the OA mixer is part of this outdoor air system too. So if your HX and evap cooler air in the outdoor air and/or exhaust air streams, then they are part of the OA system and should be listed in the outdoor air system equipment list.

Here's an example from TermRhGenericOAHeatRecPreheat.idf. I told you before you don't need a controller, but I was referring to a water coil controller, not the OA controller. For your application, the evap cooler would replace the electric heating coil and be connected in the exhaust air stream. I don't really think it matters, in your case, if you list the evap cooler before the HX or after. But practice is to list in order from outdoor air node (in the example below, the air entering the heating coil) to the OA mixing boxes OA inlet (i.e., the Outdoor Air Stream Node Name input in the OutdoorAir:Mixer object). So the equipment list order in the example below is ... heater, HX, OA mixer)

What you see here is the "Outdoor Air System". And notice that the equipment listed in AirLoopHVAC:OutdoorAirSystem:EquipmentList make up the entire OA system. If equipment is not listed here, it will not be called (simulated) by the program.

  AirLoopHVAC:OutdoorAirSystem,
    OA Sys 1,                !- Name
    OA Sys 1 Controllers,    !- Controller List Name
    OA Sys 1 Equipment,      !- Outdoor Air Equipment List Name
    Reheat System 1 Avail List;  !- Availability Manager List Name

 OutdoorAir:Mixer,
    OA Mixing Box 1,         !- Name
    Mixed Air Node,          !- Mixed Air Node Name
    Heat Recovery Outlet Node,  !- Outdoor Air Stream Node Name
    Relief Air Outlet Node,  !- Relief Air Stream Node Name
    Air Loop Inlet Node;     !- Return Air Stream Node Name

 AirLoopHVAC:ControllerList,
    OA Sys 1 Controllers,    !- Name
    Controller:OutdoorAir,   !- Controller 1 Object Type
    OA Controller 1;         !- Controller 1 Name

  AirLoopHVAC:OutdoorAirSystem:EquipmentList,
    OA Sys 1 Equipment,      !- Name
    Coil:Heating:Electric,   !- Component 1 Object Type
    Outdoor Air Preheat Coil,!- Component 1 Name
    HeatExchanger:AirToAir:SensibleAndLatent,  !- Component 2 Object Type
    OA Heat Recovery 1,      !- Component 2 Name
    OutdoorAir:Mixer,        !- Component 3 Object Type
    OA Mixing Box 1;         !- Component 3 Name

  Controller:OutdoorAir,
    OA Controller 1,         !- Name
    Relief Air Outlet Node,  !- Relief Air Outlet Node Name
    Air Loop Inlet Node,     !- Return Air Node Name
    Mixed Air Node,          !- Mixed Air Node Name
    Outside Air Inlet Node,  !- Actuator Node Name
    0.4333,                  !- Minimum Outdoor Air Flow Rate {m3/s}
    1.3,                     !- Maximum Outdoor Air Flow Rate {m3/s}
    NoEconomizer,            !- Economizer Control Type
    ModulateFlow,            !- Economizer Control Action Type
    19.,                     !- Economizer Maximum Limit Dry-Bulb Temperature {C}
    ,                        !- Economizer Maximum Limit Enthalpy {J/kg}
    ,                        !- Economizer Maximum Limit Dewpoint Temperature {C}
    ,                        !- Electronic Enthalpy Limit Curve Name
    4.,                      !- Economizer Minimum Limit Dry-Bulb Temperature {C}
    NoLockout,               !- Lockout Type
    FixedMinimum;            !- Minimum Limit Type

  Coil:Heating:Electric,
    Outdoor Air Preheat Coil,!- Name
    FanAndCoilAvailSched,    !- Availability Schedule Name
    1.0,                     !- Efficiency
    2000,                    !- Nominal Capacity {W}
    Outside Air Inlet Node,  !- Air Inlet Node Name
    Outside Air Inlet Node Preheated,  !- Air Outlet Node Name
    Outside Air Inlet Node Preheated;  !- Temperature Setpoint Node Name

  HeatExchanger:AirToAir:SensibleAndLatent,
    OA Heat Recovery 1,      !- Name
    FanAndCoilAvailSched,    !- Availability Schedule Name
    0.4333,                  !- Nominal Supply Air Flow Rate {m3/s}
    .76,                     !- Sensible Effectiveness at 100% Heating Air Flow {dimensionless}
    .68,                     !- Latent Effectiveness at 100% Heating Air Flow {dimensionless}
    .81,                     !- Sensible Effectiveness at 75% Heating Air Flow {dimensionless}
    .73,                     !- Latent Effectiveness at 75% Heating Air Flow {dimensionless}
    .76,                     !- Sensible Effectiveness at 100% Cooling Air Flow {dimensionless}
    .68,                     !- Latent Effectiveness at 100% Cooling Air Flow {dimensionless}
    .81,                     !- Sensible Effectiveness at 75% Cooling Air Flow {dimensionless}
    .73,                     !- Latent Effectiveness at 75% Cooling Air Flow {dimensionless}
    Outside Air Inlet Node Preheated,  !- Supply Air Inlet Node Name
    Heat Recovery Outlet Node,  !- Supply Air Outlet Node Name
    Relief Air Outlet Node,  !- Exhaust Air Inlet Node Name
    Heat Recovery Secondary Outlet Node,  !- Exhaust Air Outlet Node Name
    200.0,                   !- Nominal Electric Power {W}
    No,                      !- Supply Air Outlet Temperature Control
    Plate,                   !- Heat Exchanger Type
    None;                    !- Frost Control Type



On 8/26/2011 1:09 PM, Jean marais wrote:
 

Bear in mind I have a 100% ODA system. The mixing box (ODA system) is not doing much. My evaporator is before the ODA equipment, not in it. That means the exhaust air is cooled down before reaching the HX, so that I over-cool the already cool room exhaust air. This has a greater exchange rate at the HX (in the ODA system with the other ODA equipment) with the incoming ODA.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <RRaustad@...> wrote:
>
> "...just before the Outdoor Air Equipment"
>
> I do not know what you mean by that. If it's working, then is must not
> be in the Outdoor Air System, which is where I thought you wanted it. I
> say this because you say the evap cooler is working, yet it is not
> listed in the outdoor air system equipment list.
>
> Why would you put it in the return path? Where exactly is your HX and
> evap cooler. Be specific.
>
> On 8/26/2011 12:27 PM, Jean marais wrote:
> >
> > This worked without a controller, not in the return path (which only
> > handles plenum objects), but just before the Outdoor Air Equipment. I
> > did not list it there. (what's the implication) The respective node
> > temperatures and humidities look good. The extra win from the heat
> > wheel is not as much as expected.
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > <RRaustad@> wrote:
> > >
> > > Yes, give it a shot. The evap cooler does not have a water coil so you
> > > do not need a controller, just the set point manager as you show. Make
> > > sure to list the evap cooler in the OA system equipment list. Equipment
> > > should be listed in order from outdoor air node to the mixer inlet node.
> > >
> > >
> > > On 8/26/2011 3:43 AM, Jean marais wrote:
> > > >
> > > > Hi Group,
> > > > The current example files show these coolers working in the supply
> > > > stream with ODA equipment objects and ODA controllers.
> > > >
> > > > I'm trying to get this to work in the exhaust air stream and propose
> > > > the following (do I need a controller object? Which would be best?)
> > > >
> > > > AirLoopHVAC:ReturnPath,
> > > > AHU Return Path, !- Name
> > > > AHU Return Air Outlet, !- Return Air Path Outlet Node Name
> > > > AirLoopHVAC:ZoneMixer, !- Component Object Type
> > > > AHUAirLoopHVAC:ZoneMixer, !- Controlled Component Name
> > > > EvaporativeCooler:Direct:ResearchSpecial, !- Component Object Type
> > > > Direct Evap Cooler; !- Controlled Component Name
> > > >
> > > > AirLoopHVAC:ZoneMixer,
> > > > AHUAirLoopHVAC:ZoneMixer, !- Name
> > > > ZoneMixer Outlet Node, !- Outlet Node Name AHU Return Air Outlet
> > > > Underground:Basement Return Outlet, !- Inlet Node Name
> > > > PierW%N%E00:PierW%N%E00 Return Outlet, !- Inlet Node Name
> > > > PierW%S%E00:PierW%S%E00 Return Outlet, !- Inlet Node Name
> > > > PierW%W%E00:PierW%W%E00 Return Outlet, !- Inlet Node Name
> > > > PierW%E0Z%E01%E02:PierW%E0Z%E01%E02 Return Outlet, !- Inlet Node Name
> > > > PierW%E03:PierW%E03 Return Outlet, !- Inlet Node Name
> > > > Hall%E00:Hall%E00 Return Outlet, !- Inlet Node Name
> > > > Hll%E0Z%E01%E02%E03%:Hll%E0Z%E01%E02%E03% Return Outlet, !- Inlet
> > Node
> > > > Name
> > > > PavilionN:PavilionN Return Outlet, !- Inlet Node Name
> > > > PavilionS:PavilionS Return Outlet; !- Inlet Node Name
> > > >
> > > > EvaporativeCooler:Direct:ResearchSpecial,
> > > > Direct Evap Cooler, !- Name
> > > > On, !- Availability Schedule Name
> > > > 0.7, !- Cooler Effectiveness
> > > > 30.0, !- Recirculating Water Pump Power Consumption
> > > > ZoneMixer Outlet Node, !- Air Inlet Node Name
> > > > AHU Return Air Outlet, !- Air Outlet Node Name
> > > > AHU Return Air Outlet, !- Sensor Node Name
> > > > , !- Water Supply Storage Tank Name
> > > > 0.0, !- Drift Loss Fraction
> > > > 3; !- Blowdown Concentration Ratio
> > > >
> > > > SetpointManager:Scheduled,
> > > > EvapCoolerOutletTemp_SP_Mgr, !- Name
> > > > Temperature, !- Control Variable
> > > > EvapCoolerOutletTemp_SP_Sch, !- Schedule Name
> > > > AHU Return Air Outlet; !- Setpoint Node or NodeList Name
> > > >
> > > > Schedule:Compact,
> > > > EvapCoolerOutletTemp_SP_Sch,
> > > > Any Number,
> > > > Through: 12/31,
> > > > For: AllDays,
> > > > Until: 06:00, 22,
> > > > Until: 20:00, 22,
> > > > Until: 24:00, 22;
> > > >
> > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > > > <RRaustad@> wrote:
> > > > >
> > > > > That sounds like an evaporative cooler.
> > > > >
> > > > > On 8/25/2011 11:50 AM, Jean marais wrote:
> > > > > >
> > > > > > Hi Everyone,
> > > > > > I have one large air handler that represents many smaller
> > ones. The
> > > > > > current real equipment has a special feature you may find
> > interesting.
> > > > > >
> > > > > > They humidify the exhaust air at the entry node for the
> > exhaust air
> > > > > > just before the thermal wheel. Because the efficiencies of heat
> > > > > > transfer for the summer case for the thermal wheel are better for
> > > > > > sensible heat than latent heat, the humidified air drops in
> > drybulb
> > > > > > temperature whilst the humidity increases.
> > > > > >
> > > > > > I would like to change the air conditions at this node from
> > whatever
> > > > > > it is, to 22 deg C. What's the best way to achieve this? Using
> > EMS or
> > > > > > Building in a humidifier lance?
> > > > > >
> > > > > >
> > > > >
> > > > > --
> > > > > Richard A. Raustad
> > > > > Senior Research Engineer
> > > > > Florida Solar Energy Center
> > > > > University of Central Florida
> > > > > 1679 Clearlake Road
> > > > > Cocoa, FL 32922-5703
> > > > > Phone: (321) 638-1454
> > > > > Fax: (321) 638-1439 or 1010
> > > > > Visit our web site at: http://www.fsec.ucf.edu
> > > > >
> > > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > > >
> > > >
> > > >
> > >
> > > --
> > > Richard A. Raustad
> > > Senior Research Engineer
> > > Florida Solar Energy Center
> > > University of Central Florida
> > > 1679 Clearlake Road
> > > Cocoa, FL 32922-5703
> > > Phone: (321) 638-1454
> > > Fax: (321) 638-1439 or 1010
> > > Visit our web site at: http://www.fsec.ucf.edu
> > >
> > > UCF - From Promise to Prominence: Celebrating 40 Years
> > >
> >
> >
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>


-- 
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL  32922-5703
Phone:   (321) 638-1454
Fax:     (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu

UCF - From Promise to Prominence: Celebrating 40 Years


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