Maker Pro
Maker Pro

electric heater efficiency



Jan 1, 1970

The tree service a talked with dumps their load as needed when their
truck-bed fills-up, a load will contain trees from two or three jobs -
a mich-mash of tree varieties and I would have to take what they dump.

The chipped material looked pretty good, although I think it would
still take 2-3 years to fully compost.

The logs where 1 to 5' long depending on diameter (they throw those
into the truck by hand) so that timberjack looks like just the ticket,
along with a small log-splitter and chain-saw. Since wood wouldn't be
my primary heat source, I don't think it would take more than one or
two loads.



Jan 1, 1970
I would think that would only be true if the outside temperature and
wind speed stayed within a fairly narrow range...
Could you explain your thinking here, I don't understand how there
could be different outputs for a solar, or gas, or wood furnaces given
a particular house, doesn't the house's R (or UA) value plus
infiltration determines its heat loss? How would the outside
temperature and wind speed effect the same house differently based
solely on furnace type?
Redundancy is probably /always/ desirable in critical systems - but I
think it's worth keeping in mind that even marginal solar systems aren't
likely to fail 100% and your fallback system should only need to make up
the difference between "degraded" performance and whatever you require. Agreed.

Another good strategy might be to anticipate worst-case conditions and
size your capacity such that your requirements will me met even at the
worst case performance level.
I'm using TMY data to estimate worst-case conditions, but am not
comfortable with the notion of depending solely on a DIY solar heating
system, I think the sun is dependable, but my DIY skills…

Do you have an opinion on solar efficiency, I'm estimating using
general efficiencies from BIS and yahoo's solar-thermal group which
seems to suggest that both passive and active panels are about 50%
efficient, although active systems can loose up to another 25% through
heat fluid transmission. I'm looking at an active system due to a use
for "summer heat".


Bob F

Jan 1, 1970
Bob F said:
There is no need to heat the room I sleep in here in Seattle. I've
got 3 comforters which keep me toasty all night with the house as low
as 45F. The bed
room is the last one I'd heat, except for certain special occasions. A
space heater takes care of those just fine, and warms up the bed in 2
minutes if
needed when I climb in.
Josepi said:
Electric blanket comes to mind there!

The comforters do just fine, with no energy expense.

I also have slept in my van up at the ski area where it probably gets into the
teens or lower. With a foam mattress and my summerweight sleeping bag, and my
heavy down bag to pull over me when I cool off, I sleep great. Insulation rules.

Bob F

Jan 1, 1970
Curbie said:

I had a chat with a local tree service who pays to dump at the local
dump, that load includes both a majority (by volume) of chipped
branched and a minority of raw logs. Since I might have interest in
both (compost and fire wood logs) as long as they can come in at their
convenience and dump the whole load, the owner I talked to seemed ok
with the idea.

I've had thoughts that a specially designed "pellet" stove to handle larger
chunks would make good use of chipped branches for "free" heating. Chipped
branches are always available frre in this city. Of course, you'd need a system
of pallet baskets and a way to move them around to handle and dry the chips.

Bob F

Jan 1, 1970
Josepi wrote:

Is there a reason all your posts show up twice?


Jan 1, 1970

It's not as wooded in Nebraska as it is by you, so I would be
dependant on a tree service company to deliver bio-mass to make
pellets, it seems to me the minute people figured out the bio-mass had
value it would become a commodity like cooking oil has, for the
bio-diesel folks.

I'm mostly interested in the logs for back-up heat and bio-mass for
compost and am not even particularly concerned about recovering the
substantial heat generated by the aerobic decomposition of the
bio-mass. Jean Pain's heating method.

I wonder how much more heat bio-mass that was pelletized and burned in
a pellet stove would generate than the aerobic decomposition of the
same bio-mass when labor and pelletizer energy is considered. Just
thinking about home-scale heating not a small commercial endeavor.



Jan 1, 1970
It seems to me that you're looking at a fuel density issue which seems
like what is being accomplished by pelletizing and it seems like the
same thing might be accomplished by pressing the bio-mass into
pseudo-logs for a regular wood stove with something like a modified
log splitter???

When I looked at pellet stoves and pelletizers, the affordable
pelletizers being talked about where mostly designed for food pellets
that where fed with low carbon bio-mass and the high-carbon
pelletizers I found suitable for wood chips seemed pretty pricey to


Jan 1, 1970
From personal experience, solar intensity is anything but constant. Even
on a clear day the input (and therefore the output) varies noticeably
from minute to minute. I heated a home in Minnesota for over a decade
with a Jøtul fireplace/stove) and the heat varied from tree to tree of
the same species.
Ok, I'm following your thinking there.
The invitation to visit the shop (just 150 mi east of Omaha) is still
open. DIY skills are easily acquired, and I might be able to offer a few
suggestions and bit of useful show-and-tell to bolster confidence. If
it's any comfort to you, I started building panels without much
experience - but there seems to be only one way to get it...
That would have to be a summer trip; I'm in the very west part of the
state and am still trying to get by with only my motorcycle. I don't
think I've ever been accused of having a lack confidence, but I am
looking at an active system for "summer heat" use reasons and it seems
to me that it may not be my skills as much as anything with moving
parts can break or wear out.
Hmm - yes. I chose not to join the Yahoo! solar-thermal group because of
Yahoo's Terms of Service, and pretty well lost interest in the group
when, after suggesting venetian blind slats for absorber construction to
one of its members, he quoted the private e-mail to the group and
reported that /I/ was building absorbers with venetian blinds. I decided
that I couldn't afford to be associated with such folk. If you happen to
run across this dufus, you might point him at
I agree that there are lots of people who don't want to see anyone
helped and will trash any idea that isn't theirs, the solar-thermal
group has its share of pin-heads as does any group, but there are some
helpful ideas out there and like here, I read there every morning.

I don't post much there because any help I could offer would be on
concentration and what I know about collection comes from that group
and BIS to begin with, and that group is mostly focused on collection,
as am I now.
(There are some folks who just plain aren't worth trying to
help.) Although I would tend to trust anything Gary Reysa told me, I'd
still want to check it out carefully Agreed.

I think there may be a lot of difference between space heating and water
heating. My not-very-refined measurements indicated a final efficiency
in the 85% ballpark for a fairly well-refined passive solar panel
incorporated into the structure wall. My largest loss came from
non-ideal transmissivity of the UV-protected twin-wall polycarbonate
glazing - a loss that I was willing to accept in trade for longevity,
improved safety, and significant reduction of other losses.

I carefully stayed away from fluid-heating systems and anything that
required non-solar power for operation. One of my quirks is that I like
machines without moving parts - another is that I like systems that do
their job reliably, silently, and efficiently without supervision.
There seems to be an on-going spiting match between the passive and
active advocates on that yahoo solar-thermal group where both side
think they have the right plan in all circumstances, and in all
circumstances the other plan is wrong. They seem to believe that the
square pegs and round holes are not an issue as much as the size on
the hammer you're using is.
Heh - did you know that purely passive systems aren't eligible for an
Energy-Star rating? There's gotta be a joke in there somewhere... :-/
In my view, the Energy-Star rating is more about helping consumers
consume than helping consumers conserve.
Drove across Nebraska (W to E) Friday. Very much warmer than what I'd
experienced at 11,000' in Colorado. Sunny - a great solar day all across
the Cornhusker State. :)
So far the whether has been nice, I don't expect that to last much




Jan 1, 1970
Not just twice...sometimes three and four times! Geeeshhh!

Apparently my NNTP provider had some problems and were not sending out a
confirmation code to my reader/poster. The usenet browser tries to post the
same one again and again until it gets a confirmation. This used to happen
frequently in Usenet groups years ago.

My apologies for this. Irritating as hell for me too.

Is there a reason all your posts show up twice?

Josepi wrote:

Jonathan Grobe

Jan 1, 1970
That's exactly the point I though I was making.
This also depends on the particular tariff of the electricity
supplier. Lots of utilities price their second and third... tier
winter residential electrical tariff very cheaply--resulting
in electricity being competitive with other fuels for heating--
simply so they can sell their baseload capacity.
When propane prices shot up a couple years, heating with
electricity was cheaper in many places.