Coil Operation On/Off

asked 2023-08-14 13:24:23 -0500

lrebello's avatar

updated 2023-08-15 09:33:00 -0500

Hello guys,

I am trying to represent a cooling coil that operates on a on/off stage (either on 100% or on 0% of total capacity) in Open Studio. Whenever the room Dry Bulb Temperature is below the Thermostat Setpoint, the coil and the fan turns on (high capacity of 17585 W).

I have modeled an airloop with a fan, a coil, a setpoint manager a diffuser and a thermal zone. I am also using an availability manager to control when I want this system to work, based on a schedule I created (Picture 1)

Picture 1

Happens that my results show that my fan is working on On/Off (which is what I want to represent), but my coil is working with partial load (which is not what I want to represent). (Picture 2)

Picture 2

Does anyone know how I can solve this (make the coil either be at full load (17585 W) or a zero load (0W))?


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shorowit's avatar shorowit  ( 2023-08-14 16:18:35 -0500 )edit

Hello @shorowit. I am not sure if that is my problem, because I want the coil to be either on 100% of its capacity or in 0% of its capacity.

I have read your answer on the post you mentioned, but I did not understand the relation since I do not have a heating system and my coil is turning on, but is not at its 100% capacity.

Can you explain more what was your ideia and how would it solve my problem?

lrebello's avatar lrebello  ( 2023-08-14 17:00:19 -0500 )edit

Your coil is working correctly. Coil:Cooling:DX:SingleSpeed cools at its 100% capacity, but it cycles to meet the zone thermostat setpoint. It cycles even in one hour. That's why your result appears that the coil is not working at 100%. If the coil keep cooling at 100% and does not cycle, it overcools the zone.

Keigo's avatar Keigo  ( 2023-08-14 22:16:26 -0500 )edit

Thanks for your answer @Keigo . One other thing I was trying to do is: As I have two Air loops with the same configuration (fan, coil, set point manager, diffuser and the Thermal Zone) and both Air Loops attend the same Thermal Zone, I was wonnndering if is possible to set up a priority on the coils. E.g. just one coil working until it reaches 100% of its hardsized value for the Cooling Capacity, and if it happens, then the second coil turns on. Do you know if that is possible an how to do that?

lrebello's avatar lrebello  ( 2023-08-14 22:23:25 -0500 )edit

ZoneHVAC:EquipmentList in EnergyPlus priorities Zone Equipements. If it does not work, you can use EMS (EnergyManagementSystem) in EnergyPlus to write a code of the control you want to do.

I'm not quite sure if you know how to model two airloops in one thermal zone in the first place, but I guess you know it since you have been here for seven years.

Keigo's avatar Keigo  ( 2023-08-14 23:06:08 -0500 )edit