How to model System 8 ASHRAE 90.1 - 2016 baseline

asked 2022-11-02 12:54:58 -0500

updated 2022-11-02 20:37:43 -0500

13830 ●76 ●24 http://bigladdersoftware.com/

I'm modeling a large office building in zone 2A using ASHRAE 90.1 – 2016, in OpenStudio. According to table G3.1.1-4, the system I should use for the baseline is the system 8. I included the system predefined by the program, in autosize mode, with 1 system per floor as indicated by Ashrae. It’s na academic project, so I don’t really have a systema selected. However, it is showing over 1,100 unmet hours. I'm using this standard for the first time and I don't really understand how I should adjust the system values. It’s an academic project, so I don’t really have a system selected. What should I change in the template to lower those unmet hours?

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answered 2022-11-06 11:11:24 -0500

egillmor
409 ●7 http://energetics-eng.com/

There are many potential causes for this, so it's impossible to guess just from your post, but you may find this post helpful in your troubleshooting. Your fan power and COP will not impact your unmet hours, those are just efficiency settings. It is almost always a sizing issue. Good luck!

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answered 2022-11-03 03:28:00 -0500

Raul Teixeira

51 ●3 ●5 http://bandorasystems.com

Hi! Are you using the weather the building was designed to? If that is the case you can try and change the HVAC sizing parameters (heating sizing factor and cooling sizing factor).

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Yes, I'm using the correct weather. But I saw that the standard presents some equations for fan power and COP, for example, so do I have to calculate it and input the results in the program or can I just use these pre-defined systems in autosize mode (and change the sizing parameters)?

lauraribeiro08 ( 2022-11-03 07:28:56 -0500 )edit

I belive you can just change the sizing parameters. It will adjust some of the power settings kepping efficiency (cop, etc). Increasing heating/cooling power might help with the unmethours, but there could be other issues like setpoints.

Raul Teixeira ( 2022-11-07 06:08:46 -0500 )edit

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How to model System 8 ASHRAE 90.1 - 2016 baseline

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How to model System 8 ASHRAE 90.1 - 2016 baseline