[RE-wrenches] Electric boiler usage?

Sun Aug 28 16:57:04 PDT 2011

The couple is building new and going for MN Powers "Triple E" new
construction program :
http://www.mnpower.com/powerofone/one_home/new_construction/

>From the web-site:
Homeowners and builders can qualify for special incentives up to $2,000 by
meeting specific energy standards. These
standards<http://www.mnpower.com/powerofone/one_home/new_construction/tierstandards.htm>cover
thermal integrity (insulation, windows and doors, exterior wind
barriers), airtight construction, moisture control, appliances, lighting,
ventilation and heating system performance for air and water. Homes built to
Triple E standards provide the homeowner with lower energy costs, a
healthier indoors, improved building durability and increased market
value. Hear
from people who have built qualifying Triple E
homes<http://www.mnpower.com/powerofone/one_home/new_construction/buildingup/November06BuildingUp.pdf>
.
With electric HW and the boiler, they dont have enough roof space (40W X 32H
with shading issues on lower portion)  to do what they want.

I know so little about heat pumps, I dont feel I have the knowledge to
reccommend.  The home is 60-70feet from the Rainy River to the front and
there in zero space behind the home.  The lot is 75-100 feet wide.  I think
it is past the time for heating changes..... I was only called in to deal
with possible PV.

Jesse

On Sun, Aug 28, 2011 at 6:30 PM, Darryl Thayer <daryl_solar at yahoo.com>wrote:

> If this is a new house someone should have calculated the design heat
> loss.  Or the UA if you know the loss BTU per hour/degree F multiply by the
> the dgreee Days, I would guess about 10,000, then multiply by 24 hours/day
> So (heat loss(BTUh/DegreeF)xHDD about 10,000x24 h/d)= annual heat loss in
> BTU/yr.  I find that when the house is built most of the time this is
> close.  For super insulated i find many times the heat loss is higher.
>
> I have worked on some net zero houses in Minnesota.
> All the houses net zero, have a heat pump.  A heat pump will reduce the
> annual heating consumption to about 1/2 to 1/3 of electric resistance.
>
> Many people use the tax credit to pay for the complete heat pump
> installation.  BUT heat pumps are very limited in the output temperature.
> The heat source can not exceed about 110 to 115 VERY Max,  higher
> temperature will require electric resistance.  The heat pump can heat hot
> water to almost 130F using what is called a desuper heater.
>
> My net zero experiance finds that the PV takes up so much space they can
> not affort solar thermal.  Suprizing as this may sound, PV for heat pump and
> heat pump for hot water and space heating.
> Darryl
> *From:* Jesse Dahl <dahlsolar at gmail.com>
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Sent:* Saturday, August 27, 2011 2:57 PM
>
> *Subject:* Re: [RE-wrenches] Electric boiler usage?
>
> Wrenches,
>
> I've talked to the homeowners today about the system.  They are using
> www.warmboard.com subflooring and are talking to the manufacturer about
> boiler size and load.  I'm hoping they have some data.  Im guessing they
> spec a boiler. Another factor we have here is dual fuel and off-peak heating
> rates.
>
> This does seem tricky!!
>
>
> Jesse
>
> Sent from my iPhone
>
> On Aug 27, 2011, at 8:50 AM, Ian Woofenden <ian.woofenden at homepower.com>
> wrote:
>
> >
> > Hi Jesse,
> >
> > If your client were mine, I'd be recommending a heat pump, which would
> lower the electrical load significantly. It will be a larger up-front
> investment, but will likely have a positive economic return, and an
> immediate reduction in grid fossil fuel use. Whether air-source or
> ground-source would depend on the climate and budget. If they were willing
> to let go of the radiant floor delivery system, a couple of mini-splits
> might do the job (depending on the climate). An HVAC contractor I work with
> recently speced a single mini-split for a 1,000 sf home in our moderate
> climate -- installed cost was $1,000. I'm putting a kWh meter on it, so
> someday I'll have data.
> >
> > I strongly recommend that you have your client add a reconditioned kWh
> meter (available for less than $50 from a couple of sources), so that they
> have a measure of actual ongoing performance of whatever heating system they
> decide on.
> >
> > Projecting your electrical usage for boiler or heat pump will be tricky,
> since it will be based on your heating degree days and the overall R-value
> of your house. Local heating contractors _should_ be able to give you an
> estimate based on generalized tables. Sometimes they only work in dollars,
> but converting to kWh is easy. But I don't think their estimate will be
> specific to the heat gain/loss of that specific house, but just based on an
> average and the cubic footage.
> >
> > I'll be interested to see what decisions are made and how it plays out.
> >
> > Ian
> >
> >> Wrenches,
> >>
> >> I am working with a family that wants to install a grid tied system that
> will offset, as close as possible, 100% of it's electrical usage.  We have
> calculated for almost all the loads except the electric boiler.
> >> Problem, they don't know which boiler they will be using. The home will
> be 1800sq ft, it will have the in floor heat between the floor joists and
> the joists will then be insulated with foil-faced insulation.
> >> Has anyone calculated a boiler like this out for annual electrical
> usage?
> >>
> >>
> >> Thanks as always,
> >>
> >> Jesse
> >
> > --
> > Ian Woofenden <ian.woofenden at homepower.com>, Senior Editor, Home Power
> magazine
> > Subscriptions: $24.95 per year PO Box 520, Ashland, OR 97520 USA
> 800-707-6585 (US), 541-512-0220
> > or download free sample issue at <http://www.homepower.com>
> > _______________________________________________
> > 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/20110828/5d3a5fa1/attachment-0004.html>