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NC-2009 EAc5:Measurement and Verification

Base Model using Option D

This is the first time I am dealing with this credit. I am confused with what the base mode (using option D) entails. Is it simply an Appendix G model calibrated in the same way the as built model is calibrated using actual usage schedules and plug load information etc, or is it something which can be arrived at through modifying the as built model. The credit language says "estimate through whole-building simulation, then subtract energy efficiency measure from measured building performance". I appreciate any help in this matter. Thanks, Kalyan

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Mon, 11/02/2015 - 18:48

My apologies, I see that this has been addressed in earlier comments. Thanks!
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Marcus Sheffer
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Mon, 11/02/2015 - 19:34

Normally you calibrate the proposed model to the actual energy use data and then create the calibrated baseline from the proposed model.

Mon, 11/02/2015 - 19:38

Marcus, Thanks for the response. Does that mean the baseline will have the same system types as proposed model. Since some time appendix G system mapping can result in system different than the proposed systems. Also is corrective action required if the saving from the calibrated model (vs calibrated baseline) are less that the savings projected by the energy model created for EAc1?
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Marcus Sheffer
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7group / Energy Opportunities
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Mon, 11/02/2015 - 19:46

Nope. The Baseline is according to Appendix G still. When you calibrate the proposed model quite often the primary aspect of the model you are calibrating are the numerous schedules. These schedules must be identical in both models. So you take the proposed model and back out all the energy saving strategies, including the HVAC system comparison if it is different. Corrective action should address what you will do in the event that the savings do not meet the level of savings predicted. Basically you will then be using the model to examine other strategies to produce more savings. You are not obligated to implement them but you are obligated to study them.

Mon, 11/02/2015 - 20:11

Understood, thanks. One last question, are there any guidelines or requirements stating how close the calibrated model needs to be to the actual consumption numbers? In some cases, especially when submetering may not be available, it can be quite difficult to get the numbers close.
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Marcus Sheffer
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7group / Energy Opportunities
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Tue, 11/03/2015 - 14:12

The IPMVP does not establish the degree of accuracy. ASHRAE guideline 14 provides suggested ranges of error for various calibration situations. Additionally, the Federal Energy Management Program (FEMP) includes recommended ranges of error (http://www1.eere.energy.gov/femp/pdfs/mv_guidelines.pdf). Keep in mind that to calibrate most energy models with any reasonable degree of accuracy you should have a target for each energy end use (lighting, heating, cooling, etc.) on a monthly and annual basis.

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