TRACE 700 - Room multipliers and PTACs

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I'm working on a multi-use building with 3 stories of apartments on top
of a story of retail. I'm using a split DX heat pump for each apartment,
which I'm simulating in TRACE as PTAC units. I know I can use zone
multipliers to group together identical units across multiple floors.

If I use room multipliers instead of simulating each and every apartment
and heat pump, how do I reflect this in the energy model? If I were to
create a system for each individual PTAC, I would set the coil
capacities to whatever the unit can put out. But I'm confused how TRACE
factors in zone multipliers with unit capacities.

For instance, let's say I have 4 identical apartment. Each has a heat
pump that puts out 12 Mbh cooling and 9 Mbh heating. In the "Create
Systems - Heating and Cooling Coil Overrides" menu, would I put the coil
capacities at 12 Mbh and 9 Mbh, with TRACE automatically creating four
identically-sized coils? Or would I have to multiply it out myself and
put the capacities at 48 Mbh and 36 Mbh, with TRACE splitting the total
capacity between the four apartments? Or would I have to do it another
way altogether?

Thank you!

Jason Lecker, EIT, LEED AP BD+C | Elm Engineering, Inc. | 900 Center
Park Drive | Suite E | Charlotte, NC 28217-9401
PHONE 704-335-0396 Ext. 103 | FAX 704-335-0399 | www.elmengr.com

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Hey Jason, did you ever figure this one out?

I usually go with trial and error, try both on a smaller scale and see how the model behaves and what the coil loads are showing in the results.

Cheers!

_______________________________
Rami Nassar CEM, LEED AP
Energy & Sustainability Consultant
www.forwardfins.com

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