How to run HVAC system in open-loop (manual air flow rate control)?
I am an electrical engineer trying to develop a thermal model for zone as shown in equation below:
<math> Tindoor(t+1) = a1Tindoor(t) + a2Toutdoor(t) + a3Qcooling(t) + a4 </math>where
<math> Qcooling(t) = <dot>m</dot>air-flowcair(Tsupply - Tindoor) </math>To get the constants (<math> a1, a2, a3, and a4 </math>), I need to keep the <math> Tsupply </math> constant and independently control <math> <dot>m</dot>air-flow</math> i.e. airflow rate set-points to the zones.
By reading the Engineering reference and other answers on this portal, I understand that I have to use
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1. AirTerminal:SingleDuct:Uncontrolled terminal for individual zones
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2. A constant fan / constant volume zone conditioning component to control the flow and a setpoint manager
to control the temperature of the air flowing into the space.
However, I keep getting many errors (such as Thermostat needed for zone even though the terminal is uncontrolled).
Are there any example IDF cases that I can refer or any place where I can get detailed instructions. Thanks.
Why are you using a constant fan / constant volume zone conditioning component if you want to vary the airflow rate? I would think that you would want a variable speed fan with a constant discharge temperature and a VAV box without a reheat coil.
You need a thermostat in the zone so EnergyPlus knows how to vary the airflow rate (i.e. it needs to know Tindoor(t) like in your equation above).
Thanks for the suggestion, I will try with the variable speed fan with constant discharge temperature.
I will add the Thermostat to the zone, but I want to manually control air flow rate. That is why I was using the uncontrolled terminal. Any suggestions on how to manage this issue.