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