[EnergyPlus_Support] Re: Fan Coil heating Issue During Thermostat Deadband

["Jean marais" <jeannieboef@xxxxxxxxx>]

"Building services today are essentially mechanical compensations for the fact that buildings are bad for what they are designed for--human life"  - Bjarke Ingels

My sentiments, exactly. 

As to your problem, could you post the expidf?

My first though was to check the cycling time parameter of the fancoil. 

Or maybe the model is "pumping away condensate" if it incorporates a tiny condensate pump with 150 mm head, but i don't think so. Maybe the fancoil has a constant minimum consumption when in standby. which version of e+ are you using?

Do you have a set maximum outlet air temperature that is being forced that is there to avoid blowing hot air into the room during the floating range operation (check setpointmanager objects in the expidf)?

Jean

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Jacob Dunn  wrote:
>
> Support Group -
> 
> I am having an issue where my fan coils are heating when the zone
> temperature is in between the thermostat heating and cooling setpoint.
>  This is for a 300,000 SF hotel renovation model, which has 300 guest rooms
> with 300 four pipe fan coil units which are connected to a hot water loop
> (boiler) and chilled water loop (chiller + cooling tower).  I used the HVAC
> fancoil template with pretty much all the default values.
> 
> I've attached an excel spreadsheet that shows a graph of the issue.  The
> graph plots fan coil heating energy against the zone mean air temperature.
>  The excel file also shows the EnergyPlus idf objects for the thermostats.
>  The chart shows that the fan coil is heating and maintaining the heating
> setpoint at 18.33 deg C, but when the setpoint floats above the heating
> setpoint and below the 22.22 deg C cooling setpoint, the fan coil drops to
> a consistent minimum energy consumption.  It only shuts completely off when
> the zone mean air temperature rises above the cooling setpoint and cooling
> is activated.
> 
> Does anybody have any ideas what is going on?  Why is the fan coil heating
> at a minimum value when the temperature is in the thermostat deadband and
> not shutting off completely?
> 
> Any help, troubleshooting tactics, or insight is appreciated!  Thanks for
> your time!
> 
> Cheers,
> 
> *Jacob Dunn - LEED AP*
> Architectural Simulation Specialist
> University of Idaho Integrated Design Lab
> 
> p_208.401.0642
> a_306 S 6th Street, Boise ID 83702
> *
> "Building services today are essentially mechanical compensations for the
> fact that buildings are bad for what they are designed for--human life"  -
> Bjarke Ingels*
>




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