Part Load, SEER or B.S.EER

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90.1 specifies part load values using SEER, which is really just a BS number. SEER can only be determined "after the fact" and most programs use unloading curves instead.

There are an infinite number of unloading curves that essentially yield the same SEER (depending on the weather), so, one could "fudge" the unloading curve to use more energy in the baseline and would still be within the constraints of 90.1/LEED

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nomnomnom fudge...


How would you know if the unloading curve you pick meets the SEER, depending on the weather?

Be Sustainable -- Never let today use up tomorrow!.

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Actually, you would have to calculate the seer AFTER you calculated, so you could re-iterate until you had EXACTLY the SEER specified. I use the TRACE 700 visualizer to calculate this exactly.

I've checked a few times and most of the default 90.1 equipment comes out with a better SEER than specified, so while it is fudging, it is technically within the constraints of LEED

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Ahh this is what Lynn Bellenger (ASHRAE President) was talking about...there needs to be a way to callibrate your model after 1yr of building occupancy  to more closely reflect empirical data, and not virtual fudge.

Be Sustainable -- Never let today use up tomorrow!.

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Agreed. This will eventually be a requirement, which our friends in the controls business will love, because it is really the only way to accurately determine full building energy by equipment! 

I think I am going to start selling TRACER summit controls!

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Hi Bob, Sounds like you know what you are talking about. Every LEED model I have made is backwards.

Where do you find TRACE 700 visualizer?

Sincerely,
Aaron Klapheck
Mechanical Engineer, LEED AP BD+C
US Army Corps of Engineers, Sacramento District

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Thanks Aaron-

The visualizer is located when you go to view your reports, under analysis reports, there's a button for "graph profiles and energy". This launches the visualizer... The first thing you should do is go to the "view menu" and mess around with what you can see. (select advanced, and table, etc)

It's reasonably intuitive, but takes a little practice. It expands what you can do in TRACE by multiple factors though..

There's a demo of the visualizer in the TRACE 700 online training ;-) 

FYI - Right now you can still get 1 year access to all the TRACE courses for $499: 

  • Online Course (2 day course)
  • LEED Demo (8 hours)
  • LEED Fan calc demo (1 hour)
It hasn't been very publicized, but it's a pretty low price and a lot of material and PDH's (23 pdhs and they are all registered with GBCI for LEED CE hours too)

http://energy-models.com/training/trace-700-12-months-all-access-pass

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Hi Bob,

Thank you for the info. The visualizer is amazing! I will be playing with this tomorrow.

I see the US Army Corps of Engineers is already a client. I work out of Sacramento and am part of the Corps. Do you know someone I could contact that has experience with USACE customers? Perhaps the Corps already paid for a subscription I could simply use.

Sincerely,
Aaron Klapheck
Mechanical Engineer, LEED AP BD+C
US Army Corps of Engineers, Sacramento District

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