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How to control the supply inlet temperature in IdealLoadAirSystem-object?

asked 2016-03-24 07:43:06 -0600

EnnaEnitsriK's avatar

updated 2016-03-24 08:41:22 -0600

I'm using the IdealLoadAirSystem-object in energyplus, and can see from the results, that when my internal gains increases (and I then get a cooling demand), the heating of my supply inlet temperature stops and then the room receives unheated outdoor-air e.g. at 4C.

This makes sense since IdealLoadAirObject tries to stick to the thermostat setpoint temperature (21C), but instead of decreasing the inlet temperature, I want to increase the supply air rate. How to do this? 1) Can IdealLoadAirSystem do this via specific settings, or 2) do I have to add another/new HVAC-opbejct?

The calculation is 100% thermal.

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Maybe I'm not reading this correctly, you want to keep the same supply temperature from heating and increase the supply air flow when there is a call for cooling?

Neal Kruis's avatar Neal Kruis  ( 2016-03-24 09:52:35 -0600 )edit

Yes, I want to keep the inlet temperature at e.g. 21C, but the amount of air coming into the room to go from e.g. 2/hr to 4/hr when a cooling load occurs. Does that make sense? :)

EnnaEnitsriK's avatar EnnaEnitsriK  ( 2016-03-25 07:54:58 -0600 )edit

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answered 2016-03-25 10:09:13 -0600

Do you want the IdealLoadsAirSystem to meet the cooling load? Depending on your setpoint temperature, that may not be possible with 21 C supply air. If you want to model a dedicated outdoor air system (DOAS) that always delivers air at 21 C and has different flow rates during cooling and heating, you might need to build up an AirLoop system.

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Okay, i'll try to look into making an airloop. Thanks! :) If I use OS and look at an exported idf-file from an OS-file with VAV-system, would it then be possible to know which and how many objects I need to make the air-loop correct? In your opinion :)

EnnaEnitsriK's avatar EnnaEnitsriK  ( 2016-03-26 04:27:14 -0600 )edit

That is a good start, though the controls for a DOAS system are going to be different. The VAV system will give you an idea of what objects are needed, but you should be able to put together a DOAS system in OS as well.

Neal Kruis's avatar Neal Kruis  ( 2016-03-28 09:33:05 -0600 )edit

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Asked: 2016-03-24 07:43:06 -0600

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Last updated: Mar 25 '16