Hot water use (gal/person/day) in residences in eQuest 3.65

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To whom it may concern:
What is the hot water use (gal/person/day) in residences according to the ASHRAE manuals?? Any comments will be highly appreciated!
Kind regards,
Jose Luis Bermudez Alcocer, Ph.D., M.Arch., B.Arch.

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Hi Jose,

I have tried to configure out the size and capacity of the hot water system
for apartments.

The result is that on the page 7-4 of ASHRAE users manual the calculations
have been given.

The snap-shot has been post -scripted after this statement:

[image: Inline image 1]

As per the curve one can bring about the hot water storage and recovery
capacity of the hot water cycle.

As in above example the number of units in the apartments is 80 so the 75
number has been chosen from the curve which is less than 80 and
the calculations have been done to bring about the recovery capacity and
hot water storage.

The corresponding numbers have been chosen as per the curve chart and hence
the recovery capacity and usable storage has been found out.The 1.4 factor
has been considered as the consideration is 70% age useful storage capacity
of the tank.

The next page on User's manual i suppose is the efficiency of the hot water
system. This is the help from my side. Hope another comments may help you
may be more.

Thanks,
Sharad.Kumar
Gurgaon,
Greenn Horizon Consulting LLP.
India.
.............................................................................................................

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1. Hot water use (gal/person/day) in residences in eQuest 3.65
(Jos? Luis Berm?dez Alcocer via Equest-users)

---------- Forwarded message ----------
From: "Jos? Luis Berm?dez Alcocer"
To: Equest-users
Cc:
Date: Sun, 24 Apr 2016 17:31:05 +0000 (UTC)
Subject: [Equest-users] Hot water use (gal/person/day) in residences in
eQuest 3.65

To whom it may concern:

What is the hot water use (gal/person/day) in residences according to the
ASHRAE manuals? Any comments will be highly appreciated!

Kind regards,

Jose Luis Bermudez Alcocer, Ph.D., M.Arch., B.Arch.

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Equest-users at lists.onebuilding.org
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Jose,

You can find the residential hot water consumption data starting on p. 50.13 of the 2015 ASHRAE HVAC Applications Handbook.

Keith Swartz, PE | Senior Energy Engineer
Seventhwave
608.210.7123 seventhwave.org

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Single family or multifamily application?

If multifamily, I also recommend the methodology from the Energy Star Multifamily High Rise Simulation Guidelines. This is the basis for modeling LEED for Homes Midrise projects, but we?ve also used it on LEED-NC jobs and the reviewers seem to appreciate using this relatively comprehensive data for multifamily energy model inputs (not that the protocols are without flaws, but at least it establishes a level playing field).

It also gives a methodology for taking credit for low flow plumbing fixtures and energy star appliances to reduce DHW flow in multifamily jobs.

Direct Link:
https://www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/mfhr/ENERGY%20STAR%20MFHR%20Simulation%20Guidelines_Version_1%200_Rev03.pdf?c7aa-f1b0

Source Page (scroll down to the Performance Path- Simulation Guidelines section:
https://www.energystar.gov/index.cfm?c=bldrs_lenders_raters.nh_mfhr_guidance

There is a performance path calculator you can download on the source page that already has the calculations set up for you.

Sincerely,

Nathan Miller, PE, LEED AP BD+C ? Mechanical Engineer/Senior Energy Analyst
RUSHING | D 206-788-4577 | O 206-285-7100
www.rushingco.com

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Last I checked, usage information in the ASHRAE handbooks ?predates modern low flow fixtures.? Energy star?s performance path calculator is a better reference for this sort of thing.

Anthony Hardman, PE, BEAP, LEED AP BD+C

Senior Building Performance Analyst

The Green Engineer, Inc.

Sustainable Design Consulting

54 Junction Square Dr.

Concord, MA 01742

O: (978) 369-8978

D: (978) 610-2801

C: (720) 840-7862

The Green Engineer, Inc. is a Certified B Corporation

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I did some ?Handbook refreshing? in response to this discussion thread and that is indeed the current case (2015 Applications, page 50.15, Table 6 footnote). The ESMFHR guidelines are a very good resource for multifamily/residential scenarios & a model I?d recommend reviewing for other cases as well.

If however you?re dealing with service hot water consumption cases falling outside of typical residential/multifamily context, I might be inclined to fall back on Applications? suggested baseline gal/day/person DHW consumption guidance for other building occupancy types. If carrying this into an energy model, I might also consider either using the hourly flow profiles (Fig 24, a few pages following), and/or the ASHRAE ?standardized? fractional schedules for various building occupancy types featured in 90.1-1989 & carried forward into a bazillion other energy standards/references.

~Nick

------------------------------------------------------------------------------------------------------------------------------

Nick Caton, P.E.

Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric

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

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

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Also an anecdotal follow up:

The ESMFRH guidelines assume that low-income housing developments will use more domestic hot water:
[cid:image002.png at 01D19EE7.01923C90]

However, on a SINGLE (emphasize single) housing authority project I worked on, where we had a contract to follow up/calibrate our energy model 1 year after construction, we had real metered water data and found out that the occupants were actually using only about 12.5 gal/occ/day. They had low-flow fixtures plumbing fixtures, but it still was about half of the value we estimated at the time of modeling.

Take from that what you will?

Nathan Miller, PE, LEED AP BD+C ? Mechanical Engineer/Senior Energy Analyst
RUSHING | D 206-788-4577 | O 206-285-7100
www.rushingco.com

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