Subhour demand metering

3 posts / 0 new
Last post

Hello everyone,

I've got a project on my hand in which the electrical demand reported in the PS-E report doesn't match the billing demand in the ES-E report.
I've found that this was due to the "demand interval" of 15 mins on the utility meter. Fixing the demand interval to 60 mins solved the matching demand problem between the PS-E and ES-E report.

I'm just curious as how does eQUEST calculate subhour demand and determined that some electric heating power in my building didn't last more than 15min.
I need a captain here. Anyone can enlighten me?

Thanks,

[Bouthillette Parizeau]

Patrick Lapierre_ing.
plapierre at bpa.ca | www.bpa.ca | t: 5143833747x2807

Les informations contenues dans le courriel que vous venez de recevoir, y compris les pi?ces jointes, sont destin?es ? l'usage exclusif de la (ou des) personne(s) identifi?e(s) comme destinataires et sont confidentielles. Si vous n'en ?tes pas le destinataire, soyez avis? que tout usage en est interdit. Si vous avez re?u ce courriel par erreur, veuillez le retourner ? l'exp?diteur et le supprimer compl?tement de votre syst?me informatique.

via Equest-users's picture
Joined: 2016-07-15
Reputation: 400

Looks like eQUEST will, with specific airside system types (not all: SZRH, VAVS, RHFS, HP, CBVAV, PSZ, PVAVS, PTAC, and PVVT) and for electric meters only, determine the coincident sub-hourly peak draw for those systems' central/zonal components (compressor/fans/reheat/baseboards/etc), and layer that on top of the remaining hourly consumptions determined elsewhere in the model (plant loads, lighting, etc). This "modified" peak which isn't quite the results of a sub-hourly timestep throughout the model is reported as "billing demand" and as a result can report higher than "metered demand."

Electric rates default to a 15 minute interval, but you can adjust that up/down.

For non-electric utilities, you can set up a daily interval for a peak-day rate structure by entering a number >60 for the interval.

Further reading at:

- Volume 3: Topics > Central Plant Components > ELEC-METER SUB-HOUR Demand Intervals

- Volume 2: Dictionary > Economic Components > UTILITY-RATE > Energy and Demand Charges > DEMAND-INTERVAL

- Volume 2: Dictionary > Economic Components > UTILITY-RATE > Energy and Demand Charges > DEMAND-WINDOW

- Special Highlight: See markups for report ES-E in Help --> Tutorials and Reference --> Detailed Simulation Reports Summary
[cid:image001.png at 01D2A715.6F474820]
[cid:image005.png at 01D2A715.6F474820]
[cid:image002.png at 01D2A714.5B3489C0]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Schneider Electric

D 913.564.6361
M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

[cid:image003.png at 01D2A714.5B3489C0]

via Equest-users's picture
Joined: 2016-07-15
Reputation: 400

Thanks for your reply Nick, always helpful.
I was not aware of the topic in Volume 3 about sub-hour demand intervals.

So upon reading, I realize my main system is a dual duct system so maybe the problems lies there. I was puzzled (and still am) because my metered/billing demands (ES-E report) were lower than my hourly demand (PS-E report). I get that your billing demand might be higher than your metered demand but I don't quite get how the hourly demand can be lower. This was drastically reducing my peak demand compared to my reference building.. which I find provided me too much savings.

I settled at running with a demand interval of 60min, which fixed the problem but I admit I'm still somewhat puzzled.

[Bouthillette Parizeau]

Patrick Lapierre_ing.
plapierre at bpa.ca | t: 5143833747x2807

De : Nicholas Caton [mailto:Nicholas.Caton at schneider-electric.com]
Envoy? : 28 mars 2017 09:29
? : Lapierre, Patrick
Cc : 'equest-users'
Objet : RE: Subhour demand metering

Looks like eQUEST will, with specific airside system types (not all: SZRH, VAVS, RHFS, HP, CBVAV, PSZ, PVAVS, PTAC, and PVVT) and for electric meters only, determine the coincident sub-hourly peak draw for those systems' central/zonal components (compressor/fans/reheat/baseboards/etc), and layer that on top of the remaining hourly consumptions determined elsewhere in the model (plant loads, lighting, etc). This "modified" peak which isn't quite the results of a sub-hourly timestep throughout the model is reported as "billing demand" and as a result can report higher than "metered demand."

Electric rates default to a 15 minute interval, but you can adjust that up/down.

For non-electric utilities, you can set up a daily interval for a peak-day rate structure by entering a number >60 for the interval.

Further reading at:

- Volume 3: Topics > Central Plant Components > ELEC-METER SUB-HOUR Demand Intervals

- Volume 2: Dictionary > Economic Components > UTILITY-RATE > Energy and Demand Charges > DEMAND-INTERVAL

- Volume 2: Dictionary > Economic Components > UTILITY-RATE > Energy and Demand Charges > DEMAND-WINDOW

- Special Highlight: See markups for report ES-E in Help --> Tutorials and Reference --> Detailed Simulation Reports Summary
[cid:image007.png at 01D2A7E4.7C41E100]
[cid:image008.png at 01D2A7E4.7C41E100]
[cid:image009.png at 01D2A7E4.7C41E100]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Schneider Electric

D 913.564.6361
M 785.410.3317
F 913.564.6380
E nicholas.caton at schneider-electric.com

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

[cid:image010.png at 01D2A7E4.7C41E100]

via Equest-users's picture
Joined: 2016-07-15
Reputation: 400