[EnergyPlus_Support] Temperatures in a water loop

[<fpasserini.tn@xxxxxxxxx>]

Iâ??m modeling a DHW loop.



PlantLoop,

    DHW Loop,                !- Name

    WATER,                   !- Fluid Type

    ,                        !- User Defined Fluid Type

    DHW Loop Operation,      !- Plant Equipment Operation Scheme Name

    Water Heater Use Loop Outlet Node,  !- Loop Temperature Setpoint Node Name

    100,                     !- Maximum Loop Temperature {C}

    3,                       !- Minimum Loop Temperature {C}

    0.00000283,              !- Maximum Loop Flow Rate {m3/s}

    0,                       !- Minimum Loop Flow Rate {m3/s}

    0.015,                   !- Plant Loop Volume {m3}

    Water Heater Use Loop Inlet Node,  !- Plant Side Inlet Node Name

    Water Heater Use Loop Outlet Node,  !- Plant Side Outlet Node Name

    Water Heater Use Branches,  !- Plant Side Branch List Name

    Water Heater Use Connectors,  !- Plant Side Connector List Name

    Demand Inlet Node,       !- Demand Side Inlet Node Name

    Demand Outlet Node,      !- Demand Side Outlet Node Name

    Demand Branches,         !- Demand Side Branch List Name

    Demand Connectors,       !- Demand Side Connector List Name

    OPTIMAL;                 !- Load Distribution Scheme



The water temperature delivered by the municipality is modeled as constantly equal to 15°C:



Site:WaterMainsTemperature,

    Schedule,                !- Calculation Method

    temp15C;                 !- Temperature Schedule Name



Schedule:Compact,

    temp15C,                 !- Name

    Temperature,             !- Schedule Type Limits Name

    Through: 12/31,          !- Field 1

    For: AllDays,            !- Field 2

    Until: 24:00, 15;        !- Field 4



As I would expect, when there is water flow the temperature of the â??Demand Side Outlet Nodeâ?? (Demand Outlet Node) is equal to 15°C: <http://oi60.tinypic.com/2mnq0km.jpg>http://oi60.tinypic.com/2mnq0km.jpg



Among the output data, the water temperature of the â??Plant Side Inlet Nodeâ?? (Water Heater Use Loop Inlet Node) is much higher: <http://oi60.tinypic.com/5zgv9i.jpg>http://oi60.tinypic.com/5zgv9i.jpg



I donâ??t understand why the temperature in the â??Plant Side Inlet Nodeâ?? is higher than the temperature in the â??Demand Side Outlet Nodeâ??. There is no element between them.

I have found in the .bnd file:

Plant Loop Return Connection,DHW LOOP,DEMAND OUTLET NODE,WATER HEATER USE LOOP INLET NODE



The water heater is on the supply side and its setpoint temperature is 40°C. No recirculation should occur.



WaterHeater:Mixed,

    Water Heater,            !- Name

    0.1,                     !- Tank Volume {m3}

    RISC Temp Schedule,      !- Setpoint Temperature Schedule Name

    0,                       !- Deadband Temperature Difference {deltaC}

    61,                      !- Maximum Temperature Limit {C}

    Cycle,                   !- Heater Control Type

    1200,                    !- Heater Maximum Capacity {W}

    ,                        !- Heater Minimum Capacity {W}

    ,                        !- Heater Ignition Minimum Flow Rate {m3/s}

    ,                        !- Heater Ignition Delay {s}

    Electricity,             !- Heater Fuel Type

    1,                       !- Heater Thermal Efficiency

    ,                        !- Part Load Factor Curve Name

    ,                        !- Off Cycle Parasitic Fuel Consumption Rate {W}

    ,                        !- Off Cycle Parasitic Fuel Type

    ,                        !- Off Cycle Parasitic Heat Fraction to Tank

    ,                        !- On Cycle Parasitic Fuel Consumption Rate {W}

    ,                        !- On Cycle Parasitic Fuel Type

    ,                        !- On Cycle Parasitic Heat Fraction to Tank

    Zone,                    !- Ambient Temperature Indicator

    ,                        !- Ambient Temperature Schedule Name

    2secondo:LocaleUTA,      !- Ambient Temperature Zone Name

    ,                        !- Ambient Temperature Outdoor Air Node Name

    0.73,                    !- Off Cycle Loss Coefficient to Ambient Temperature {W/K}

    1,                       !- Off Cycle Loss Fraction to Zone

    0.73,                    !- On Cycle Loss Coefficient to Ambient Temperature {W/K}

    1,                       !- On Cycle Loss Fraction to Zone

   0.00000283 ,                        !- Peak Use Flow Rate {m3/s}

    ,                        !- Use Flow Rate Fraction Schedule Name

    ,                        !- Cold Water Supply Temperature Schedule Name

    Water Heater Use Inlet Node,  !- Use Side Inlet Node Name

    Water Heater Use Outlet Node,  !- Use Side Outlet Node Name

    1.0,                     !- Use Side Effectiveness

    ,                        !- Source Side Inlet Node Name

    ,                        !- Source Side Outlet Node Name

    ,                        !- Source Side Effectiveness

    0.00000283;              !- Use Side Design Flow Rate {m3/s}



WaterUse:Equipment,

    RISC,                    !- Name

    DHW,                     !- End-Use Subcategory

    0.00000283,              !- Peak Flow Rate {m3/s}

    DHWschedule,             !- Flow Rate Fraction Schedule Name

    RISC Temp Schedule;      !- Target Temperature Schedule Name



Schedule:Compact,

    RISC Temp Schedule,      !- Name

    Any Number,              !- Schedule Type Limits Name

    THROUGH: 12/31,          !- Field 1

    FOR: AllDays,            !- Field 2

    UNTIL: 24:00, 40;        !- Field 4



Regards



__._,_.___

Primary EnergyPlus support is found at:
<http://energyplus.helpserve.com>http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
<http://www.energyplus.gov>http://www.energyplus.gov

The group web site is:
<http://groups.yahoo.com/group/EnergyPlus_Support/>http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.


<http://geo.yahoo.com/serv?s=97476590/grpId=3387488/grpspId=1705007389/msgId=31549/stime=1395315514>

<https://groups.yahoo.com/neo/groups/EnergyPlus_Support/info;_ylc=X3oDMTJlcXBxMzd2BF9TAzk3MzU5NzE0BGdycElkAzMzODc0ODgEZ3Jwc3BJZAMxNzA1MDA3Mzg5BHNlYwN2dGwEc2xrA3ZnaHAEc3RpbWUDMTM5NTMxNTUxNA-->Visit Your Group
* <https://groups.yahoo.com/neo/groups/EnergyPlus_Support/members/all;_ylc=X3oDMTJmYm9uam50BF9TAzk3MzU5NzE0BGdycElkAzMzODc0ODgEZ3Jwc3BJZAMxNzA1MDA3Mzg5BHNlYwN2dGwEc2xrA3ZtYnJzBHN0aW1lAzEzOTUzMTU1MTQ->New Members 9
<https://groups.yahoo.com/neo;_ylc=X3oDMTJkczRybnJjBF9TAzk3NDc2NTkwBGdycElkAzMzODc0ODgEZ3Jwc3BJZAMxNzA1MDA3Mzg5BHNlYwNmdHIEc2xrA2dmcARzdGltZQMxMzk1MzE1NTE0><http://l.yimg.com/ru/static/images/yg/img/email/new_logo/logo-groups-137x15.png>
? <https://info.yahoo.com/privacy/us/yahoo/groups/details.html>Privacy ? <mailto:EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx?subject=Unsubscribe>Unsubscribe ? <https://info.yahoo.com/legal/us/yahoo/utos/terms/>Terms of Use
__,_._,___