Heat pump split system and DOA

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I am not sure if I set up my proposed model correctly.  I have three zones (multiple rooms in each zone) created under one system (incremental heat pump) and DOA unit selected from tab on the selection screen.  is this correct?  also after i run the model my space cooling energy use is higher in the design and baseline. is this commom?

Anonymous's picture
Anonymous

Yes. Rooms --> Zone ---> System. You have one system correct, not 3? Keep in mind to always look at the "line-up" from the Plant down, not the Space up...if you know what I mean. Since you have a heatpump, not knowing if this will be geothermal, but typically you can only have one wellfield, so you willAlso keep in mind that you will only have one heat rejection device (geothermal or tower). But I may be getting a head of myself so let me know if you have any more questions.

Be Sustainable -- Never let today use up tomorrow!.

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When I say one system I mean heat pump as a system type.  I have more than one unit (HP-1, HP-2, etc).  I guess my question is setting it up for LEED do i have to have a system for each  heat pump unit or can i use one system and have multiple zones.  Hope that makes sense.

Anonymous's picture
Anonymous

Proposed Design:


Base the number of systems on the ventilation unit...you have Heat pumps serving more than one space, then set up all heat pumps as individual zones within the System, and then drag/drop rooms into the appropriate zone. Your coils will be set to the zone level. Whereas in the dedicated outdoor air unit it'll be set at the system level.


Base Case:


You will need to follow the ASHRAE 90.1 rules on zoning the building based on your basecase...this may result in more or less zones compared to your zones. And you will need individual Systems for each Zone to account for the varying sizes and airflows. Then you'll need individual plants per system to account for fan/compressor break out and individual efficiencies.

Be Sustainable -- Never let today use up tomorrow!.

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