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Posted by Morris Dovey on February 19, 2008, 12:40 pm
 
Frank Scrooby wrote:


I've been corresponding with Eskom, and will suggest that South
Africans /need/ to be discussing that - and that they would be
doing themselves (and the entire world) a lot of good by having
that discussion right out in public.


Yup - the problem is serious and will affect every South African
citizen, as well as everyone with whom South Africa does
business.


<admitted non-solution snipped>


That's US$600, and probably not an unreasonable retail cost. I
would guess that it might be possible to produce such a unit for
less than a third of that amount, but I'll add that I have no
handle on the cost of doing business in SA.

At some point you guys are going to have to make a decision
whether you're working to get rich off each other - or whether
you really want to solve the problem. By the time blackouts and
service cutbacks became necessary, the option to do both (make a
fast Rand _and_ solve the problem) had faded considerably.


You already know the answer - a flat panel.


Simpler? How about heating water in a pot over an open fire - is
that simple enough for you? Simple is about cutting production
labor/equipment costs in the short term. Go, instead, for the
lowest level of complexity that *solves* the problem. If the cost
of that is more than you care to pay, then live with the problem.

Depending on design, you may be able to skip the welding/brazing
in favor of soldering, and it's possible to produce dual-function
panels (air _and_ water heating) - but your stated objective
reveals that your aim is to make a fast Rand rather than solve
the greater problem.


You can do that - but you might want to spend some time talking
with some old-timers to learn why that approach to water heating
fell into disuse.


Water heaters, alone, aren't going to get you there. They
probably won't even provide enough savings to maintain the status
quo. Sorry to be the one to speak the words you hate hearing, but
you (South Africa and Eskom) have reached a tipping point. You
will need to do better than grasp at straws.


Every possible solution is worth exploring carefully and
dispassionately.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Posted by J. Clarke on February 19, 2008, 3:40 pm
 
Everybody, just bear in mind one thing.  In South Africa half the
population is living on under a hundred bucks a year.  We look at
movies and pictures and whatnot and we see Charlize Theron and the
glittering cities and we forget that N!xau and his family living in
huts in the Kalahari are also part of it.

In that economy, 1600 bucks is a rich person's luxury, it's like
telling some kid in the ghetto in the US that he needs a Ferrari to
get to his job at McDonalds when a bicycle will do him just fine.

Morris Dovey wrote:

Seems to me that it's to Eskom's benefit to be able to provide power
to as many customers as possible.  Any time the power is off they're
not making money.  Although why a country for which uranium is a
low-value byproduct of their real business and which most assuredly
does have the engineering capabilty to make use of it is so heavily
invested in coal I really don't understand.


It apparently already is.


Is that "the answer" or is it an "inside the box" answer based on
experience with the US climate and the US economy?


I think that that's what the people who don't have electricity _are_
doing.  And likely some number of those who do have it are heating
over a hotplate.


Define "solves".  Individual effort is not going to increase
generating capacity, which is what is needed to _solve_ the problem.
But if it can save a few bucks for a family that is already strapped
for cash then why not?


What's wrong with him making a fast Rand?  Maybe if he makes enough
fast Rand he'll be able to work out a way to make something better
that people can afford.  And maybe he can in the process provide jobs
to two or three of those folks who are trying to get by on under a
hundred bucks a year.


Perhaps because cheap electricity became available and proved to be
more convenient?


They have a basic problem--betwen 1994 and the present the number of
households with electric service has more than doubled.  If demand
matches that then it has outstripped supply--building generating
capacity that fast from scratch just doesn't happen--the lead time on
power plants is too long.

Cheap solar water heaters won't solve that problem, but I don't see
where they are going to _hurt_.


Yep.  Including his.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)



Posted by Morris Dovey on February 19, 2008, 4:50 pm
 "J. Clarke" wrote:

You're absolutely correct in pointing out the width of the
economic spectrum.


Also true. I'd guess that those living in less developed won't be
anywhere nearly as much affected as those living in more
developed areas - and that for people in less developed areas
it'll be less about having hot water at the tap and A/C to keep
cool in the summer than about availability of essential services.


It appears to have a complex history, in which the desire for
control of wealth and political positioning may have played no
small part. None of this is unique to South Africa - they just
happen to be first.


It's _an_ answer based on experience, study, observation, and a
fair amount of experimentation. The physics is independent of
location.


Agreed - but let's not lose sight of the broader picture. It's
not a solution for the greater part of the population who live in
well-developed areas. Kinda like heating with wood in the US -
people living in the north woods can heat with wood, but no one
would consider that a viable solution in the city.


Hmm - good question. I would guess that "solves" would mean
finding an workable alternative to wholesale electricity -
preferably on a more or less permanent basis, but for at least
long enough to enlarge the wholesale generating capacity.


There's nothing inherently wrong with that so long as it doesn't
interfere with the quality of the result. Therein lies the rub. A
low-quality result won't solve the problem - it will simply
ensure that there's a secondary crisis a short distance down the
road, with general conditions worsening at each subsequent
crisis. It's like trying to repair a compound fracture with
morphine - it's necessary to do more than just make it stop
hurting for the moment.


In part - but there's more to it than that.


All true, but discussion of how it all came about leads directly
to finger-pointing and recrimination for which there really isn't
time.


Again, I agree. Let's notice that energy consumption is (at least
presently) on a growth curve. I'm of the opinion that there isn't
a single solution ("magic bullet") that makes everything better.
A few people are rushing foreward waving boxes of band-aids
claiming that theirs is best. Almost totally lacking is any
vision that we're going to need to use a mix of solutions and
methods, and that we need to think in terms of systems/subsystems
components.


That's what I said. I'd add the proviso that structural engineers
be brought into the picture and listened to. The wood frame
building in northern Indiana in which I had K-4 classes had such
an arrangement, and a couple of years after I moved away had the
tank come crashing straight down through the building. Like steam
boiler explosions, it wasn't a terribly common event, but neither
was it extremely rare. I'll "'fess up" to a certain amount of
resulting bias - and I'll continue to advocate for careful and
dispassionate consideration of _all_ methods.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Posted by J. Clarke on February 19, 2008, 12:51 pm
 Frank Scrooby wrote:

Well, let's look at showers.

Now, I'm thinking while writing here and I live in the US where
English units are the norm rather than metric so there's going to be
some mixing of units--please forgive that because I realize that it's
a distraction.

In the Navy they don't want you to spend more than 5 minutes in the
shower aboard ship (the problem is not _hot_ water, it's water at all)
while I find that some studies in college dorms found that 7.5 was
more typical for civilians, so let's set 5 minutes as a "quick shower"
for civilians.  The local water company distributed flow restrictors a
while back that cut down the flow to 2 gallons a minute.  So 5 minutes
at 2 gallons/minute is 10 gallons or 35 liters.  Now, I can't find a
standard for shower temperature but I'm seeing various informal
research efforts online reporting 106-107F, so call it 107 for
calculation purposes.  If your tank temperature is 45C and the
municipal temperature is 20C then that's 68F and 113F respectively.
To get 107 out of that you need to mix .87 liter hot with .13 parts
cold, so you need 30 liters for a single Navy shower.  So 1-2/3
showers is going to empty the tank.  If you can get a reliable 45C out
of it then it would seem to me that planning on using one for each
family member and then adding one for the pot so to speak would let
everybody have a 7.5 minute shower with some reserve left over.  The
major problem I can see is that the water's not going to be hot in the
early morning, so a before-work shower may not benefit.

Sounds like it's certainly worth trying as a pilot project and see how
it works out.  Simple way to do it would be to have the solar feeding
into the electric heater so that it gets preheated water.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)



Posted by Trygve Lillefosse on February 19, 2008, 7:48 pm
 On Tue, 19 Feb 2008 07:51:43 -0500, "J. Clarke"


Exept the gallons, wher you'we got your own.:-)


Dont think people will like to shower, using 35L/5 min. It's simply
not enough unless you are camping.

I have been in a navy myself, although in a different country, but
with the same problem. We did not have a low-flow shower, and I do not
think it would have been needed either.


Now we are talking. This will ofset a lot of the electric heating
needs, while still giving the same comfort as before.

--
SEE YA !!!
Trygve Lillefosse
AKA - Malawi, The Fisher King

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