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90.1 2010 vs 90.1 2007

asked 2014-10-29 16:46:10 -0500

Out of curiosity, what are some of the some of the biggest changes/challenges energy modelers are seeing on projects using the new version of the standard?

Any lessons learned?

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answered 2014-10-30 14:01:11 -0500

Folks from PNNL working on 90.1 analysis published two good papers that detail the modeling approach for each addendum taking 90.1-2004 to 90.1-2007 and 90.1-2007 to 90.1-2010. Those documents are:

These were created to document the DOE Commercial Prototype Models, but the modeling approaches are a useful reference for anyone needing to understand how a particular part of 90.1 might be interpreted into energy model inputs.

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answered 2014-10-30 12:39:27 -0500

The major changes we have seen with 90.1-2010 is in the lighting and daylighting side of things. LPDs are lower, and daylighting is required by code in many space types. Daylighting in itself is very complicated, with a calculation being applied to each zone to first see if it needs daylighting, and then to find the controlled fraction of lights in the zone. Another interesting thing is that depending on the building/space types, the 2010 baseline might be only slightly better then 2007, and in other cases it is 30% or more.

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answered 2014-10-30 13:29:47 -0500

I would add that there are also 2 new system types for the baseline: system 9 and system 10 for heat only buildings. It stops the need for modelling baseline cooling systems in a heat only design. I haven't noticed any significant challenges in the energy modelling side, most of it is very similar, the documentation for LEED however has increased significantly and is for sure more challenging.

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Addenda DN of 90.1-2007 includes these heating and ventilation systems, although I've been told they are mislabeled and should be the same as 90.1-2010.

MatthewSteen gravatar image MatthewSteen  ( 2014-10-30 13:50:46 -0500 )edit

answered 2014-10-29 19:23:39 -0500

updated 2014-10-29 19:44:57 -0500

I think the big changes affecting the energy modelers are coming with 90.1-2013.

Here's a link with all of the changes...

Here's the direct link to the Appendix G presentation...

Check out the page about window-to-wall ratios! And computer rooms!

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The fact that 90.1-2013 establishes requirements for commercial refrigeration is interesting. The refrigeration industry has been starved for a consistent baseline.

Lincoln gravatar image Lincoln  ( 2014-10-30 11:42:45 -0500 )edit

answered 2015-10-29 08:36:00 -0500

One area we have seen a major rework & reduction is the exterior lighting allowances. The whole table of allowances has been reorganized to categorize the allowance for each type of lighting based upon the project's environment, i.e: rural, urban, national parks. While a few of the allowances are higher, many are more restrictive than before. This is an area we have worked to explain to our designers/clients as it could have major implications depending on the project.

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answered 2015-10-29 09:03:09 -0500

I know you cannot take credits due to DCV in fan parking and carkeeper systems in hotel rooms.

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Asked: 2014-10-29 16:46:10 -0500

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Last updated: Oct 29 '15