[Bldg-sim] ASHRAE 90.1 zoning for System 7 - variable temp and humidity requirements

[Bill Bishop]

Hi Madhav,

I suggest you consider adding separate single-zone systems for select spaces based on interpreting G3.1.1.c (if you're modeling per Appendix G).
If you go the simple route and model one System 7 per floor in the Baseline, it could be argued that you should model the Proposed design with the same humidification for the entire floor, the same as the Baseline is modeled. (See language in Table G3.1 No.4 that "Temperature and humidity control set points and schedules... shall be the same for proposed design and baseline building design."
If your project allows for flexibility in modeling approach (i.e. you don't have to follow a strict interpretation of Appendix G.) then your Option 2 of modeling multiple Systems 7 matching your Proposed zoning makes sense.

Regards,
~Bill

William Bishop, PE, CEM, LEED AP, ASHRAE (BEMP, BEAP, CDP)
Senior Associate / Sustainability & Energy Engineer of Distinction
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From: Bldg-sim <bldg-sim-bounces at lists.onebuilding.org> On Behalf Of Madhav Munshi via Bldg-sim
Sent: Thursday, February 13, 2025 10:53 AM
To: bldg sim <bldg-sim at lists.onebuilding.org>
Subject: [Bldg-sim] ASHRAE 90.1 zoning for System 7 - variable temp and humidity requirements

External Email: Treat links and attachments with caution.
Hello everyone,

We are working on a project - 5 floors and greater than 200,000sf. Each floor has spaces with different temperature and humidity requirements.

For example
Space type 1: 70F - 50% RH Strict control
Space type 2: 70-75F 40% min - 60% max RH,
Space type 3: 70-75F 50% max RH summer only

This happens on all floors.

Proposed zoning has spaces combined on the basis of different environmental requirements.

How would you approach the zoning for the ASHRAE Baseline?

  1.  One System 7 per floor: If we do floor by floor, we will be adding system level humidification for all spaces on that floor and allow whatever happens to each room. Definitely might end up humidifying spaces that don't need humidification

  1.  Multiple Systems per floor: Split up each floor zoning by temp and humidity and have multiple Sys 7's per floor.

  1.  Alternative Approach??
What do you all think? I am inclined to start with 1 system 7 per floor and stick with the ASHRAE requirements.


Thank you



Madhav



MADHAV MUNSHI | BEMP

Senior Associate

mmunshi at kohlerronan.com<mailto:mmunshi at kohlerronan.com>



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KOHLER RONAN | Consulting Engineers

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212.695.2422 F 212.695.2423



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