Can't find the source of space heat elec use

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So my proposed model is attached if anyone can help me narrow this down?
The bin file is TMY2 weather file for Fairbanks Alaska.

I can't figure out what is causing electrical usage for space heating. All space heating energy should be fuel-oil (for the boiler) unless I'm overlooking something.

In my BEPS report you will see 19 MBTU of space heating under "electrical" but I can't find the source (5567 KWH for elec space heating in BEPU).

My PS-A Report (also attached) shows electrical use throughout the year for space heating with a max of 1.1 MWH in January.

Has anyone seen this before? It isn't pilot light related because that's zeroed out.

The only other possibility I can think of is it being boiler related.

Chris Baker
CCI CAD Drafter

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Chris Baker2's picture
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Havn't looked at your file - but see if the electric input ratio for boiler
is non-zero (EIR).
-Rohini

R B's picture
R B
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Ahhh nice! Thank you sir.

-Chris

Chris Baker2's picture
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This is how I was able to get cooling down to baseline level in proposed.

Control setpoints were probably part of it. I did go back in the DX cooling controls and change it to ?warmest? with 70F max reset.

Just thought I would share this in case others in the future have similar problems.

The issue was definitely the supply flow, however.

The system has 5,000 CFM design capacity but only when the exhaust fan is blowing air out at the kitchen hood (Zone GNE5). I had to set up a Min Flow Schedule so that scheduled flow was about 154 CFM for the kitchen. The schedule corresponds with the exhaust fan schedule for the kitchen now. So when the exhaust fan kicks on there is an ample source of makeup air from the duct.

This cut 4,000 KWH from my proposed model just in cooling energy and lowered heating energy by another 400 MBTU (an inadvertent but added benefit).

But big thanks to RB and Brian Fountain for assisting!

-Chris

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I was even able to increase the cost savings for cooling and heating further in my proposed model.

I set all zones in that system to receive .16 CFM per SF of OSA. I original had 900 CFM of OSA assigned to that zone with 2600 CFM supply flow.

Now that the supply flow is around 151-152 CFM the OSA flow is reasonable for the system.

If you are following a similar path to mine to address excessive cooling, however, I highly suggest going back to the baseline and making sure your system is set up in a similar fashion with the OSA flows matching in both models (for all zones).

Making OSA numbers match in both models is something I didn?t know about a couple months ago but I?ve been told it can be a sticking issue when it comes to LEED reviewers lately. (it should match exactly to the CFM).

To check this you can run your simulation, then click on the zone values you want to review and click ?summary? tab. You will see the OSA flows for that zone and you can check to ensure they are the same in both models.

-Chris

Chris Baker2's picture
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Just a little clarification: Outdoor air numbers shall usually match to a certain point. If your proposed model is more than 50% above ASHRAE 62.1, then they will differ.

Envoy? de mon iPhone

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Thanks Julien.

I was able to modify the models so that the OSA matched exactly to the CFM in each.

Reviewers have been really sticky on this subject as of late ? or so I?ve been told.

You ideally want your OSA cfm to match exactly in both models to prevent review issues.

-Chris

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