[Greenbuilding] Wood-burning Cooking, Central Heating, & Hot Water: Advice Needed

Thu Feb 22 11:32:56 CST 2007

Thank you, Norbert and Greenbuilders!

A woodburning cookstove may be overkill, but what I really want is zero
carbon emissions and zero fossil fuels, and to a lesser extent, the ability
to cook with flame and a back-up for cooking, heat and hot water, when the
grid is down (as I have mentioned before, we are connecting our PV system to
the grid, and the State/Private Utility--they appear to be one and the
same--do not allow battery back-up if you take the equipment rebate). Since
we have an abundance of renewable biomass on the farm, a wood-burning stove
seems feasible. I thought maybe we could save money and serve simplicity by
piggy-backing the other functions of heat and hot water with the woodburning
(and some of the manufacturers suggest this as well).

Cheers and Many Thanks!

Mary

Mary Bull, Co-director
Greenwood Earth Alliance, Save the Redwoods - Boycott the Gap Campaign
252 Frederick, San Francisco, CA 94117 http://www.gapsucks.org
Chalice Farm and Sustainable Living Center, 748 Montgomery Rd, Sebastopol CA
95472
415-731-7924 - 415-509-1188 chalicenew at earthlink.net

----- Original Message ----- 
From: "Norbert Senf" <mheat at mha-net.org>
To: "'Greenbuilder list'" <greenbuilding at listserv.repp.org>
Sent: Thursday, February 22, 2007 8:55 AM
Subject: Re: [Greenbuilding] Wood-burning Cooking, Central Heating, & Hot
Water: Advice Needed

At 08:38 AM 2/22/2007 -0800, dantonioli at earthlink.net wrote:
>(snip)
>
>The only thing a central boiler can't do in Mary's situation is provide
heat
>for cooking. (snip)

In my view, a central boiler would be completely
inappropriate for an 800 sq.ft,
efficient house.

A builder friend of mine built himself an R-2000 1000 sq. ft. house near
Ottawa (8700 degree days) about 20 years ago. He
heated it with a single 1500 watt
electric resistance heater (cost of the heater was $30).

 From the limited data that I've been able to
obtain on outdoor boilers, even the
good ones require a relatively high burn rate to
get best performance. So the output
would be hugely mismatched with the demand in this case.

Even a wood fired cookstove could easily be
overkill in an 800 sq. ft. high efficiency
house. To supply a design heat load of 1.5 kW,
your burn rate on the coldest day of the year
in Ottawa would have to be on the  order of 1
lb/hr. So, figure an average burn rate
of 1/2 lb hr, or 1/2 cord per year.  One way this could work would
be with intermittent burns and low tech storage, for example an air core
floor:
http://www.energybuilder.com/pdf/asme-acs-tn.pdf

-------------------------------------------
Norbert Senf---------- mheat(at)heatkit.com
Masonry Stove Builders
25 Brouse Rd.
RR 5, Shawville------- www.heatkit.com
Québec J0X 2Y0-------- fax:-----819.647.6082
---------------------- voice:---819.647.5092

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