[Equest-users] Huge electrical consumption for DHW

[Busman, Michael R]

Morteza,

You can find information in the ASHRAE 2011 HVAC Applications Handbook.  Start in chapter 50 about 50.12 and 50.14.  If you don't have access to the handbook, your mechanical engineer should have it and could maybe review with you what the daily gallons of usage should be in addition to a simple hand or spreadsheet calc of kWh as a comparison number.  I would definitely suggest focusing on the sf/occupant and laundry usage as well as the other items I listed below.  Finally, if you are modeling an existing building and can get historical electric consumption and demand data, I would use that to try and calibrate the model to the historical data.  By the way, is electric resistance water heating included in the proposed model?

Mike

Michael R. Busman, CEM
Lead Project Engineer II

Chevron Energy Solutions
A Division of Chevron U.S.A., Inc.
145 S. State College Blvd.
Brea, CA  92821
Direct  714-671-3561
Fax     714-671-3438
eFax   866-420-0335 (Include my Full Name followed by "CAI:MHTZ" on Cover Sheet)
Mobile 310-387-2083
mbusman at chevron.com<mailto:mbusman at chevron.com>



From: Morteza Kasmai [mailto:morteza.kasmai at gmail.com]
Sent: Monday, July 22, 2013 9:55 AM
To: Busman, Michael R
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Huge electrical consumption for DHW

 Mike,
Thank you so much for your respond.
All the inputs are eQUEST defaults; with your suggestions I have to revise them. I reviewed Section 7 of ASHRAE 90.1-2007, but I couldn't find related data for the baseline model. I have the exact data for the proposed model based on the MEP engineer calculations but if I input those data for the baseline model the project will not achieve any savings from this category. It would be very helpful if you let me know where I can find these data.
Regards,
Morteza

[https://lh6.googleusercontent.com/Uuukta80GuFfvKouzA0mdSvUXqml7MtSwSiw-evuGMU=w147-h43-p-no]


On Mon, Jul 22, 2013 at 10:43 AM, Busman, Michael R <MBusman at chevron.com<mailto:MBusman at chevron.com>> wrote:
Morteza,

I took a very quick look at some of the inputs in wizard mode.  Some of the input assumptions appear to be on the high side and I'd suggest double-checking.


*         20 gal/person

*         sf/person - many of the spaces have an allocation of 100 or 200 sf/occupant, which might overstate the number of occupants

*         10 laundry loads/week/apartment - It's been many years since I've had little ones or teenagers in the house, so my memory isn't too clear on how many loads/week we used to do, but this seems on the high side, but I could be wrong and worth checking.

*         I noticed 2 DHW heaters defined, one at 135 deg. and the other at 110 deg.  I didn't look at the input file so I don't know how these get assigned or if both get assigned or just the first heater.  135 deg. for residential use is high if you want to avoid scalding and will also overstate your kWh.

*         Finally, I'd suggest reviewing ASHRAE service hot water heating requirements.  They indicate average daily DHW usage for apartments of about 40 gal/apartment and maximum usage as high as 80 gal/day.  Please note that the numbers are based on OLD data before low flow fixtures and devices became common.  So a comparison to the ASHRAE numbers should be made with the ASHRAE numbers bumped down.

*         I think the ASHRAE chapter on DHW also charts typical hourly usage.  You might want to check versus your DHW schedule.

I hope the above helps or maybe gets you on the right path.

My best,

Mike Busman


Michael R. Busman, CEM
Lead Project Engineer II

Chevron Energy Solutions
A Division of Chevron U.S.A., Inc.
145 S. State College Blvd.
Brea, CA  92821
Direct  714-671-3561<tel:714-671-3561>
Fax     714-671-3438<tel:714-671-3438>
eFax   866-420-0335<tel:866-420-0335> (Include my Full Name followed by "CAI:MHTZ" on Cover Sheet)
Mobile 310-387-2083<tel:310-387-2083>
mbusman at chevron.com<mailto:mbusman at chevron.com>



From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>] On Behalf Of Morteza Kasmai
Sent: Sunday, July 21, 2013 9:29 AM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Huge electrical consumption for DHW


Dear eQUEST experts,
I have Electrical Water Heater for the Residential and Non-residential parts of this model. I allowed eQuest to auto-size domestic hot-water use. BEPS report shows huge electrical consumption for DHW, more than the total consumptions of all others. Is there something wrong?
Please find the attached pd2 and inp files of the project.
Your comments would be greatly appreciated.
Morteza






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