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Define different HVAC operation trigger temperature and setpoint temperature

asked 2018-01-15 03:34:34 -0500

Amy Lee gravatar image

Can energyplus able to define different HVAC operation trigger temperature and setpoint temperature? For example, HVAC will provide no cooling(shut off) until indoor temperature above 30 degree, but when it operating, the setpoint temperature will be 26 degree. If you have experience about this, please advice. Your suggestion is really appreciated. Thanks !

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answered 2018-01-15 05:14:52 -0500

bbrannon4 gravatar image

updated 2018-01-21 02:51:57 -0500

This is commonly referred to as a deadband or driftpoint in the setpoint temperature range. For example say you have a setpoint range of 20-26 degrees, but you give it a deadband of 4 degrees, so the cooling won't actually kick on until 30 degrees, and the heating won't until 16 degrees. By convention this also means that the cooling system with overcool by the same deadband (in this case down to 22 degrees). (at least this is the most common control strategy that I see)

Another phrasing for this is throttling range, which in the example above would be 8 degrees, or twice the driftpoint. The only way I know how to do it natively and simply is with a ZoneControl:Thermostat:StagedDualSetpoint, which can define throttling ranges, as defined in the input output manual. If you need something more specific or more complicated, then I think you will need to look into EMS.

I find this as a major lacking point in EnergyPlus simple dual control thermostats, because it's such a common control strategy. In fact I have searched and found: https://unmethours.com/question/17507... and https://unmethours.com/question/17656... both of which are asking the same things as you, but neither have really been answered.

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answered 2018-01-15 04:49:18 -0500

Avi gravatar image

I believe you can do that with Availability Managers. You can read about that in the Input Output Reference. You would probably need to combine several Availability Managers in order to achieve on and off rules. Another option, a bit more complicated would be to use EMS.

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Asked: 2018-01-15 03:34:34 -0500

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Last updated: Jan 21 '18