BeOpt - New Construction ACCA Manual J HP Autosizing

asked 2025-05-07 19:06:30 -0500

agamas
23 ●4

Hello,

When modeling new construction residential models, BeOpt includes a note regarding the capacity of the system being sized per ACCA Manual J, I wonder if there's a way to regard that autosizing calculation, or if the overall size of the system can be seen/found somewhere?

I'm struggling pinning down that information for a variable speed heat-pump system (woking with BeOpt 2.8).

Any assitance would be appreciated! $C:\fakepath\Autosizing 1.png$ (/upfiles/17466627125362091.png)(/upfiles/17466626984348892.png)

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answered 2025-05-08 10:47:08 -0500

shorowit

12570 ●220 ●9 https://www.nrel.gov/b...

The autosized HVAC capacities are found once you run on the simulation on the output screen. Right-click on the End Use graph (lower-left graph) and choose Graph Type > HVAC Capacities. You'll see something like this:

image description

A few notes:

You should really consider using BEopt 3. BEopt 2.8 was released over 7 years ago. There have been significant improvements to our heat pump models (especially variable-speed) in BEopt 3, with more pending. In addition, BEopt 3 allows you to see the design loads by component (walls, roof, infiltration, etc.) that were used to autosize the equipment.
While the design load calculations are consistent with or based on Manual J, BEopt is not an ACCA approved software tool.

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I see, thanks! ...wondering if by any chance it also appears somewhere in the metadata CSV files?

Also thanks for the comments, the main reason I've been using v2.8 is because having then Energy Rating Index (even if not official) has been important during iteration process, I would really really like if that could come back in a future realease.

agamas ( 2025-05-08 11:41:49 -0500 )edit

Hello, Following up with an indirectly related question.

After running a case, I notice the "TEMP" gets populated with metada organized through numerical prefixes (eg., 1_Hourly, 2_Hourly, 3_Hourly). I wonder what are the diferent prefixes calling out? What are they distinguishing from each other?

In particular I've been looking to the "*Table" csv files, where the system capacities are captured. I'm having difficulties comparing the different files and making sense of why there many (with different values) for individual cases.

Thx

agamas ( 2025-05-13 15:04:23 -0500 )edit

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BeOpt - New Construction ACCA Manual J HP Autosizing

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