[RE-wrenches] Load size for off-grid lodge

jason pozner zzyyzzx11 at gmail.com
Tue May 11 11:46:46 PDT 2010


Thanks all for the good suggestions on and off-list.  We are going to go
with a monitoring program.  There were just too many variables to even try
to guess with this project.

Cheers,
Jay
Nunatak AES

On Fri, May 7, 2010 at 7:59 AM, <holtek at sbcglobal.net> wrote:

>  As a bit of a swerve off the path of this string....I am designing a
> grid-tie system for a building that is being "greenovated". Trying to lock
> down a LEED req'd percentage shaving of annual demand. I know there is a
> place to find assumptions from DOE, but I'm not that confident in those
> because they can't possibly plug in all factors. Any sources out there that
> might drill down the numbers a bit better? Or do I keep trying to hit the
> swinging dart board blindfolded? EPRI seems to be designed for
> utilities, grid EE's and such - haven't found any pertinent load assumption
> info on the website.....
> Holt E. Kelly
> Holtek Fireplace & Solar Products
> 500 Jewell Dr.
> Waco TX. 76712
> 254-751-9111
> www.holteksolar.com
>
> ----- Original Message -----
> *From:* Allan Sindelar <allan at positiveenergysolar.com>
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Sent:* Thursday, May 06, 2010 11:50 PM
> *Subject:* Re: [RE-wrenches] Load size for off-grid lodge
>
> Jason,
> We attempted this about 2-3 years ago for a project on one of Ted Turner's
> ranches. This was to be a top-of-the-line eco-lodge at 10,000' below a ridge
> in the northern Rockies in New Mexico, with two 7kW Provens and a 3-phase
> Sunny Boy/Sunny Island system. Due to the lack of real load analysis, and
> the need to have large but essentially unknown capacity at the lodge, the
> initial estimate was about $900K, as I recall.
>
> We never did the project, as they decided to go with dual generators. We
> did get compensated for extensive design work.
>
> You may need to focus on large efficiencies and then put a usage fraction,
> like 60%, on the electrical engineer's traditional load calcs. That's what
> we did. And write in a section stating that you make no warranties as to the
> sufficiency of the system to meet actual loads, as the loads can't be
> accurately determined.
>
> Here's what I wrote in the initial pre-proposal:
>
> <!--[if !supportLists]-->*I.                   *<!--[endif]-->*Load
> Profile Methodology and Limitations*
>
> Typical off-grid PV systems are designed and sized based on a rigorous load
> analysis as an essential first step. The load analysis is a detailed listing
> of every electricity-consuming device, with power consumption and expected
> daily usage figures, used to develop an accurate profile of total expected
> daily kilowatt-hour consumption. From this data a power system of specific
> design and capacity is developed.
>
> This approach is not possible for the XX Lodge, so an alternative approach
> must be used to establish target design criteria. EPRI (Electric Power
> Research Institute, the research arm of the U.S. electric utility industry)
> has developed Technology Assessment Guides to predict power use for various
> residential and commercial sectors. The comparative sector of lodging at
> 12,000 square feet in the western U.S., establishes a figure of 223
> kilowatt-hours per day. This is a base figure, for conventional design
> without energy-conserving measures, with adders for electric heat, hot
> water, cooking and air conditioning, none of which will be used at XX Lodge.
>
>
> From this *we have estimated that XX Lodge may be expected to have a total
> average daily load not exceeding 190 kilowatt-hours per day*, or 85% of
> the EPRI figure. This is the figure used in this preliminary budget
> analysis. This may be considered to be quite conservative; that is, careful
> attention to energy-conserving approaches during design and construction are
> likely to considerably reduce this figure.
>
> Remember too that if they now have generators, they're not likely to
> conserve, as generator power is pretty much all-or-nothing, with efficiency
> unimportant within the gennie capacity. So there's a fair amount of load
> management and education to fit in.
>
> Hope this little bit helps.
>
>   <![endif]-->
>
> *Allan** Sindelar*
> Allan at positiveenergysolar.com
> NABCEP Certified Photovoltaic Installer
> EE98J Journeyman Electrician
> *Positive Energy, Inc.*
> 3201 Calle Marie
> Santa Fe, New Mexico 87507
> *505 424-1112*
> www.positiveenergysolar.com
>
>
> jason pozner wrote:
>
> Hey all,
>
> I am trying to size a PV/generator system for a 10,000 ft2 off-grid
> hunting/snowmobile lodge with outbuildings.  The goal is to significantly
> reduce current generator run time.  I was wondering if any of you have
> experience or suggestions for calculating time of use of lights, etc in a
> lodging situation.  My interviews with the rancher have proven fruitless to
> pin down any time of use of most loads, though I do have an estimated run
> time for the genny in summer and winter.  I did get a pretty good snapshot
> of his connected load by turning on all I could on and clamping the feeds.
>
> The lodge is 18 rooms, 4 for the help, and a few outbuildings.  Has anyone
> sized any off-grid lodges?   Any other ways to approach the moving target of
> such a fluctuating load at a guest lodge?
>
> Thanks
> Jay Pozner
> Nunatak Alternative Energy Solutions
>
>
>
> ------------------------------
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:www.members.re-wrenches.org
>
>    ------------------------------
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Options & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20100511/225202d8/attachment-0004.html>


More information about the RE-wrenches mailing list