modeling a cooling coil water inlet node

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The image above shows the components needed to model a Controller:WaterCoil. I am doing this for the purpose of Dehumidification control on a system of type AirLoopHVAC:UnitarySystem. I happen to be using a coil of type Coil:Cooling:DX:TwoStageWithHumidityControlMode.

In theory, the Controller:WaterCoil is supposed to talk to the Humidity and Temperature Setpoint managers for a zone and adjust the amount of cold water in the coil. However, I cannot find actuator node description in the model. In fact, I don't see any cooling coil water inlet nodes in the model. This is required input for the Controller:WaterCoil "Actuator Node Name".

Is it a problem to use the IDF editor in doing this? Does and actuator need to be created? (I've tried this)

I am not sure what modelling software you are using but the actuator node is the node on your cooling coil that you want to vary to meet the criteria you have set. So for instance, if you want an air humidity of 8g/kg and an air temperature of 15°C coming off your coil, your sensor node for those criteria is the air node coming out of the cooling coil and the actuator node is the water node going into the coil, the water entering the coil needs to vary in flow and temperature for the air to meet the criteria.

This is the case for a water coil, however, if you have a DX coil you do not need a Controller:WaterCoil. The system will know itself to look into the correct places. You will need setpoints and to put the right type of control in your DX system.

4.3k

Annie Marston

answered 2014-12-10 09:12:55 -0500

29.7k

Julien Marrec

updated 2017-02-17 07:58:14 -0500

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Annie, Thanks for this insight about DX coil control in EnergyPlus! This approach of controlling the coil directly, with EMS code, and a zone humidistat worked out.

E Boxer (2014-12-10 10:58:17 -0500) edit

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