dayton j grant on tue 20 feb 01
I would like to start a thread about solar kilns ,does anyone have one,
does any one know how to make one ,I would like to what other people
think about this idea .
Bret Hinsch on wed 21 feb 01
Solar kilns are nothing new. The earliest hard paste porcelain in Europe
was probably fired using solar lenses. European kiln technology was still
far behind China, so initially the only way they could reach high enough
temperatures to melt the kaolin was through solar power.
Many of the people involved in these early experiments ended up going blind
from exposure to the high intensity light, so be very careful if you try
this yourself. The wonderful book "The Arcanum" about the origins of
Meissen porcelain describes these experiments.
Bret in Taipei
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com
Khaimraj Seepersad on wed 21 feb 01
Hello to All ,
Dayton ,
from time to time this topic pops up and nothing comes
of it .
Here is the address of the working article from -
Ceramics Monthly - year / month ?
[ or Ceramics Review not sure ? ]
Zelijko Kujundzic - Experiments in Solar Energy .
He [ Mr. Z ] lived in Washington State when last I
checked , but that was maybe 5 years + ago .
The telephone number I had just rang .
I understand that he had not pursued the matter .
Similar to Solar Kilns are Solar furnaces , in France
, Nantick , Mass. and Japan [ since 1950's to 1963]
temperatures generated are in excess of 3,400 deg.c
The article I have [ very short ] says that even feeble
sunlight will melt refractory bricks .
These Furnaces are however using 10 m diameter
parabolic concentrators.
Also very expensive.
I have however not done any physical research , as I
mentioned to you .
I thought you were one of the old contributors to the
original Solar Kilns topics and so did not mention
the above .
Will keep you informed .
Khaimraj
-----Original Message-----
From: dayton j grant
To: CLAYART@LSV.CERAMICS.ORG
Date: 21 February 2001 5:35
Subject: SOLAR KILNS?
>I would like to start a thread about solar kilns ,does anyone have one,
>does any one know how to make one ,I would like to what other people
>think about this idea .
vince pitelka on thu 22 feb 01
> Solar kilns are nothing new. The earliest hard paste porcelain in Europe
> was probably fired using solar lenses. European kiln technology was still
> far behind China, so initially the only way they could reach high enough
> temperatures to melt the kaolin was through solar power.
This is a rather creative theory, and I admire you for sticking your neck
out so far. Firing porcelain does not involve melting kaolin. And of
course at the time hard-paste porcelain was invented in Germany the Germans
already had sophisticated twin-firebox downdraft kilns which they had been
using for several hundred years for firing saltglazed stoneware, and early
porcelain was fired in similar kilns. If they were experimenting with
"solar lenses" as you say, blinding each other in the process, they
certainly could never have achieved temperatures necessary to fire true
porcelain.
Best wishes, and keep up the dreaming -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Earl Brunner on fri 23 feb 01
ANd I think we are dreaming about solar kilns period. I recall some
work done on this back in the 70's (during the so called energy crisis).
The solar collector panels (mirrors) were large and bulky, the firing
chamber small and relatively useless. May be fun to fiddle around with,
but without some kind of break through in technology not commercially
practical. We've had some pretty god breakthroughs in refractories and I
still don't think it's enough.
Then, you get to cone 8 and a half and a cloud appears and blocks out
the sun....
vince pitelka wrote:
>> Solar kilns are nothing new. The earliest hard paste porcelain in Europe
>> was probably fired using solar lenses. European kiln technology was still
>> far behind China, so initially the only way they could reach high enough
>> temperatures to melt the kaolin was through solar power.
>
>
> This is a rather creative theory, and I admire you for sticking your neck
> out so far. Firing porcelain does not involve melting kaolin. And of
> course at the time hard-paste porcelain was invented in Germany the Germans
> already had sophisticated twin-firebox downdraft kilns which they had been
> using for several hundred years for firing saltglazed stoneware, and early
> porcelain was fired in similar kilns. If they were experimenting with
> "solar lenses" as you say, blinding each other in the process, they
> certainly could never have achieved temperatures necessary to fire true
> porcelain.
> Best wishes, and keep up the dreaming -
> - Vince
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Khaimraj Seepersad on fri 23 feb 01
Greetings to All ,
Vince ,
with respect to you formidable knowledge and with further
respect to you , I regretfully type this .
Fortunately , I saw this letter before I sent out congratulations to
Bret Hinsch and his excellent information.
You need to read -
Ceramic Masterpieces - Kingery and Vandiver
chapter 9 - Botteger Porcelain -
especially pages 165 bottom paragraph to 167 and
168 last paragraph .
briefly -
Count E.W.von Tschirnhaus - uses Sunlight in a Solar Furnace
[ 1674 - 1679 ] - Research appreciated , he is made a member
of The French Royal Academy [ 1683 ] .
Studies Saxon Mineral Resources with Pabst , establishes 3
glass houses - producing burning lenses larger than 1 metre in
diameter.
Achieves much higher temperatures than previously possible
in Europe - 1694 experiments with Porcelain development.
1699 reports on melting sand and lime [ 1436 deg. c ]
1706 Pabst , Tschirnhaus and Botteger on secret Porcelain
-discovery business .
1707 - Tschirnhaus reports eyes ruined by burning glass and
the making of red porcelain .
January 15th 1708 , Botteger notes state - white translucent
ware achieved.
1709 - March 28 - Botteger tells the king of porcelain manufature .
Early bodies were - colditz clay and calcium sulfate , soon became
Kaolin from Aue .
[ from - Ancient Inventions - James and Thorpe ]
Burning Glasses are available from Pliny's time [ cauterizing
wounds ] - also 1st century A.D . China and earlier 5th Century B.C
in the scientific work of Mo Jing [ Mohist Canon ] by Mo Zi .
However the Archimedes Giant Burning Mirrors is a medieval
tradition with no foundation.
1853 - Sir H. Layard - Nimrud , Assyria returns with a lens for
magnifying or concentrating the sun's rays [ as pronounced by
Sir David Brewster - physicists and specialists in optics ] .
Said Lens is on display in the British Museum .
I believe Jon Singer has the Kingery and Vandiver book if you
need a 2nd reply for verification.
Apologies Khaimraj
-----Original Message-----
From: vince pitelka
To: CLAYART@LSV.CERAMICS.ORG
Date: 23 February 2001 5:24
Subject: Re: SOLAR KILNS?
>> Solar kilns are nothing new. The earliest hard paste porcelain in Europe
>> was probably fired using solar lenses. European kiln technology was
still
>> far behind China, so initially the only way they could reach high enough
>> temperatures to melt the kaolin was through solar power.
>
>This is a rather creative theory, and I admire you for sticking your neck
>out so far. Firing porcelain does not involve melting kaolin. And of
>course at the time hard-paste porcelain was invented in Germany the Germans
>already had sophisticated twin-firebox downdraft kilns which they had been
>using for several hundred years for firing saltglazed stoneware, and early
>porcelain was fired in similar kilns. If they were experimenting with
>"solar lenses" as you say, blinding each other in the process, they
>certainly could never have achieved temperatures necessary to fire true
>porcelain.
>Best wishes, and keep up the dreaming -
>- Vince
>
>Vince Pitelka
>Appalachian Center for Crafts
>Tennessee Technological University
>1560 Craft Center Drive, Smithville TN 37166
>Home - vpitelka@dtccom.net
>615/597-5376
>Work - wpitelka@tntech.edu
>615/597-6801 ext. 111, fax 615/597-6803
>http://www.craftcenter.tntech.edu/
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Bruce Girrell on fri 23 feb 01
> I would like to start a thread about solar kilns ,does anyone have one,
> does any one know how to make one ,I would like to what other people
> think about this idea .
For those who wish to consider the use of a solar kiln, I suggest that you
first define what you mean by the term. Do you want to use solar radiation
directly with a concentrating device, such as lenses or mirrors, or do you
want to collect solar radiation over a longer period of time to be used on
demand for firing a kiln?
Some issues to consider for direct usage of solar radiation:
1) How do you plan to keep the energy focused on the target for the length
of time necessary to reach temperature? Usually a computer-controlled array
of mirrors, called a heliostat, is required.
2) How do you plan to distribute the heat evenly throughout the kiln? In
other words, with the beam of light coming from one direction, how do you
avoid melting one side of a pot while the other side has not even gotten
warm yet?
3) How do you plan to handle temporary interruptions of the solar input by
clouds or nightfall?
4) How will you control the solar input? Blasting the ware with full power
from the outset is a good way to produce piles of cracked pots.
5) How will the heat energy be admitted to the kiln space and what sort of
heat loss will result? If the beam is admitted through an open side of the
kiln, heat losses from convection become an issue.
Some issues to consider for indirect usage of solar radiation:
1) In what form will the energy be stored until needed (electrical,
mechanical, chemical?)
2) How will the kiln make use of the stored energy? In most cases, the
easiest way is to fire an electric kiln by extracting the stored energy as
electricity, but if you're creative you may find some other interesting
ways.
3) How much power over how long of a time will be needed to complete the
firing? How long will it take to accumulate that much stored power (plus a
little more to account for losses) and how much of the storage medium
(batteries, flywheels, hydrogen/oxygen, etc.) is required to deliver that
power over that period of time?
4) Where will you house the storage and control equipment (it's not going to
be small)? Are you capable of maintaining it?
Issues in general:
1) Why do you want to do this project (ecological reasons, curiosity, lack
of "conventional" power)?
2) How much will it cost?
3) What benefits come as a result of that cost? Do those benefits warrant
the cost?
4) Is this the best way to satisfy your reason for doing the project?
This time I'm just asking the questions, since I've already answered many of
these points in two previous lengthy posts on this subject. Also, there have
been several magazine articles written on the subject.
Bruce Girrell
Hank Murrow on fri 23 feb 01
>Date: Fri, 23 Feb 2001 13:02:10 -0800
>To: bigirrell@microlinetc.com
>From: Hank Murrow
>Subject: Re: SOLAR KILNS?
>Cc:
>Bcc:
>X-Attachments:
>
>>> I would like to start a thread about solar kilns ,does anyone have one,
>>> does any one know how to make one ,I would like to what other people
>>> think about this idea .
>
> ******Well, for the person who started this thread here goes. Back
>in 1975 I developed a doorless(lifting) fiberkiln which required very
>little fuel to fire to stoneware temps. An architect friend visited my
>studio some years later and reported that he had just visited Boeing in
>Seattle to see their solar lab. One of the wonders he saw was a heliostat,
>which consisted of a Tedlar dome inflated by a solar blower(battery
>backup) with a 15 foot diameter mirror inside. the mirror was capable of
>focusing a light beam continuously onto a selected spot to produce as much
>as 50,000BTU/hr. These heliostats were to be installed in a giant array in
>Boardman, WA to focus their energy on a tower-boiler for steam generation.
>Since my kiln was only using 120,000BTU/hr of natural gas full on, and was
>having to heat the 80% volume of nitrogen to boot; I reasoned that the
>50,000 BTU/hr could be focused through a quartz mirror under the kiln and
>onto a black silicon carbide target inside the kiln, the rate of heating
>controlled by an iris. Since the kiln could be sealed entirely except for
>the less than 2" diameter aperture in the floor, it would take far less
>solar energy to fire it than with gas as a fuel. Above C/1, the energy
>inside a fiberkiln is almost entirely radiant, so given some time, the
>chamber would equalize to the same temperature everywhere. As with mel's
>hybird electric/gas kiln, reduction might be accomplished by a tiny oil or
>gas drip. My friend said the Boeing engineers expected the cost of the
>Heliostat to drop to $2000 when produced in quantity. BTW, they weighed
>less than 400#; dome, mirror, tracking mechanism and all. I am very happy
>with my kiln as it stands, firing on Natural gas @ $18 per firing; but if
>my ship ever comes in you can bet I'll be asking Boeing if they are ready
>to ship one 50,000 BTU/hr dome to Eugene, OR. There's a kiln here that's
>ready to try sunlight directly as an energy source.
>
>Hank in Eugene
>
>
Larry Phillips on fri 23 feb 01
Khaimraj Seepersad wrote:
> You need to read -
>
> Ceramic Masterpieces - Kingery and Vandiver
But is there anything in it about solar kilns? Yoru references did not
seem to be about them.
--
Procrastinate now!
http://24.113.44.106/larry/
Khaimraj Seepersad on sat 24 feb 01
Hello to All ,
Larry ,
my response was to Vince Pitelka , who was responding to
Bret Hinsch -
Bret typed -
>> Solar kilns are nothing new. The earliest hard paste porcelain in Europe
>> was probably fired using solar lenses. European kiln technology was
still
>> far behind China, so initially the only way they could reach high enough
>> temperatures to melt the kaolin was through solar power.
>
Vince replied -
>This is a rather creative theory, and I admire you for sticking your neck
>out so far. Firing porcelain does not involve melting kaolin. And of
>course at the time hard-paste porcelain was invented in Germany the Germans
>already had sophisticated twin-firebox downdraft kilns which they had been
>using for several hundred years for firing saltglazed stoneware, and early
>porcelain was fired in similar kilns. If they were experimenting with
>"solar lenses" as you say, blinding each other in the process, they
>certainly could never have achieved temperatures necessary to fire true
>porcelain.
>Best wishes, and keep up the dreaming -
>- Vince
What Vince said was incorrect - you must read the whole chapter 9 of
Ceramic Masterpieces - Kingery and Vandiver
- to see where Vince makes his errors .
__________________________________
As to functional Solar Kilns - Zelijko Kujundzic shows 8 small pots fired
by using his 3lb coffee can firing chamber. The idea was shown to work
and the next step is to enlarge the firing chamber .
The Article is - Experiments in Solar Energy .
All I have is a photocopy , not the magazine or the date when the article
was published.
The French Furnace got around the tracking the sun problem by using
heliostats set in tiers . Cost was tremendous .[ 1970 ]
Anyone wishing to pursue this idea will simply have to do it. Then if
they are generous enough , be willing to share how they did it .
Khaimraj
-----Original Message-----
From: Larry Phillips
To: CLAYART@LSV.CERAMICS.ORG
Date: 23 February 2001 18:07
Subject: Re: SOLAR KILNS?
>Khaimraj Seepersad wrote:
>
>> You need to read -
>>
>> Ceramic Masterpieces - Kingery and Vandiver
>
>But is there anything in it about solar kilns? Yoru references did not
>seem to be about them.
>
>--
> Procrastinate now!
>
> http://24.113.44.106/larry/
Larry Phillips on sat 24 feb 01
Khaimraj Seepersad wrote:
>
> Larry ,
> my response was to Vince Pitelka , who was responding to
> Bret Hinsch -
Well sure, but it is a public forum, nicht wahr?
> What Vince said was incorrect - you must read the whole chapter 9 of
> Ceramic Masterpieces - Kingery and Vandiver
> - to see where Vince makes his errors .
Fair enough. My point was that the references you cited from the book
seemed to be about small experimental setups, rather than practical
solar kilns.
I don't have access to the book, but I'll keep my eye out for it.
--
Procrastinate now!
http://24.113.44.106/larry/
Earl Brunner on sat 24 feb 01
Even with a 15% increase in natural gas cost over the last 12 months, I
think I'll stick to my Geil kiln for a while.
It fits in my back yard.
Khaimraj Seepersad wrote:
> Hello to All ,
>
> Larry ,
>
> my response was to Vince Pitelka , who was responding to
> Bret Hinsch -
>
> Bret typed -
>
>>> Solar kilns are nothing new. The earliest hard paste porcelain in Europe
>>> was probably fired using solar lenses. European kiln technology was
>>
> still
>
>>> far behind China, so initially the only way they could reach high enough
>>> temperatures to melt the kaolin was through solar power.
>>
> Vince replied -
>
>> This is a rather creative theory, and I admire you for sticking your neck
>> out so far. Firing porcelain does not involve melting kaolin. And of
>> course at the time hard-paste porcelain was invented in Germany the Germans
>> already had sophisticated twin-firebox downdraft kilns which they had been
>> using for several hundred years for firing saltglazed stoneware, and early
>> porcelain was fired in similar kilns. If they were experimenting with
>> "solar lenses" as you say, blinding each other in the process, they
>> certainly could never have achieved temperatures necessary to fire true
>> porcelain.
>> Best wishes, and keep up the dreaming -
>> - Vince
>
>
>
> What Vince said was incorrect - you must read the whole chapter 9 of
> Ceramic Masterpieces - Kingery and Vandiver
>
> - to see where Vince makes his errors .
> __________________________________
>
> As to functional Solar Kilns - Zelijko Kujundzic shows 8 small pots fired
> by using his 3lb coffee can firing chamber. The idea was shown to work
> and the next step is to enlarge the firing chamber .
>
> The Article is - Experiments in Solar Energy .
> All I have is a photocopy , not the magazine or the date when the article
> was published.
>
> The French Furnace got around the tracking the sun problem by using
> heliostats set in tiers . Cost was tremendous .[ 1970 ]
>
> Anyone wishing to pursue this idea will simply have to do it. Then if
> they are generous enough , be willing to share how they did it .
> Khaimraj
>
>
>
>
>
> -----Original Message-----
> From: Larry Phillips
> To: CLAYART@LSV.CERAMICS.ORG
> Date: 23 February 2001 18:07
> Subject: Re: SOLAR KILNS?
>
>
>
>> Khaimraj Seepersad wrote:
>>
>>
>>> You need to read -
>>>
>>> Ceramic Masterpieces - Kingery and Vandiver
>>
>> But is there anything in it about solar kilns? Yoru references did not
>> seem to be about them.
>>
>> --
>> Procrastinate now!
>>
>> http://24.113.44.106/larry/
>
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Earl Brunner on sat 24 feb 01
Yeah and Vince has graciously retracted his original.
Something that well heeled people do. They aren't afraid to acknowledge
it when they may make a mistake.
If this was in fact such a great cost effective way do make a living
with pottery we would be doing it by now.
The fact that people have tinkered with a concept doesn't automatically
make the concept practical. They'
ve been working on hydrogen cars for at least 30 years that I know of.
No body in my neighborhood owns one.
Khaimraj Seepersad wrote:
> Hello to All ,
>
> Larry ,
>
> my response was to Vince Pitelka , who was responding to
> Bret Hinsch -
>
> Bret typed -
>
>>> Solar kilns are nothing new. The earliest hard paste porcelain in Europe
>>> was probably fired using solar lenses. European kiln technology was
>>
> still
>
>>> far behind China, so initially the only way they could reach high enough
>>> temperatures to melt the kaolin was through solar power.
>>
> Vince replied -
>
>> This is a rather creative theory, and I admire you for sticking your neck
>> out so far. Firing porcelain does not involve melting kaolin. And of
>> course at the time hard-paste porcelain was invented in Germany the Germans
>> already had sophisticated twin-firebox downdraft kilns which they had been
>> using for several hundred years for firing saltglazed stoneware, and early
>> porcelain was fired in similar kilns. If they were experimenting with
>> "solar lenses" as you say, blinding each other in the process, they
>> certainly could never have achieved temperatures necessary to fire true
>> porcelain.
>> Best wishes, and keep up the dreaming -
>> - Vince
>
>
>
> What Vince said was incorrect - you must read the whole chapter 9 of
> Ceramic Masterpieces - Kingery and Vandiver
>
> - to see where Vince makes his errors .
> __________________________________
>
> As to functional Solar Kilns - Zelijko Kujundzic shows 8 small pots fired
> by using his 3lb coffee can firing chamber. The idea was shown to work
> and the next step is to enlarge the firing chamber .
>
> The Article is - Experiments in Solar Energy .
> All I have is a photocopy , not the magazine or the date when the article
> was published.
>
> The French Furnace got around the tracking the sun problem by using
> heliostats set in tiers . Cost was tremendous .[ 1970 ]
>
> Anyone wishing to pursue this idea will simply have to do it. Then if
> they are generous enough , be willing to share how they did it .
> Khaimraj
>
>
>
>
>
> -----Original Message-----
> From: Larry Phillips
> To: CLAYART@LSV.CERAMICS.ORG
> Date: 23 February 2001 18:07
> Subject: Re: SOLAR KILNS?
>
>
>
>> Khaimraj Seepersad wrote:
>>
>>
>>> You need to read -
>>>
>>> Ceramic Masterpieces - Kingery and Vandiver
>>
>> But is there anything in it about solar kilns? Yoru references did not
>> seem to be about them.
>>
>> --
>> Procrastinate now!
>>
>> http://24.113.44.106/larry/
>
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Khaimraj Seepersad on sat 24 feb 01
Hello to All ,
Earl ,
Vince is indeed a gracious and intelligent man , but how
exactly was I supposed to clarify for Larry ???
This is not a Vince bashing , didn't you see how my first letter
went out ?
As to Solar Kilns , all I can say is test , test , test.
It's obvious that others are curious about them and will try to
make one.
Like I said a while ago , when and if , I get some positive results
I will report back - but you do have to crawl before you can walk .
Khaimraj
-----Original Message-----
From: Earl Brunner
To: CLAYART@LSV.CERAMICS.ORG
Date: 24 February 2001 10:18
Subject: Re: SOLAR KILNS?
>Yeah and Vince has graciously retracted his original.
>Something that well heeled people do. They aren't afraid to acknowledge
>it when they may make a mistake.
>
>If this was in fact such a great cost effective way do make a living
>with pottery we would be doing it by now.
>
>The fact that people have tinkered with a concept doesn't automatically
>make the concept practical. They'
>ve been working on hydrogen cars for at least 30 years that I know of.
>No body in my neighborhood owns one.
>
vince pitelka on sun 25 feb 01
> > What Vince said was incorrect - you must read the whole chapter 9 of
> > Ceramic Masterpieces - Kingery and Vandiver
> > - to see where Vince makes his errors .
Khaimraj -
I guess I'll have to keep an eye out for that book in order to see where I
made my errors. As I have stated, I am fascinated to find out that
scientists trying to develop true porcelain really were melting things with
solar lenses, and that they had achieved temperatures high enough to fire
porcelain by this method. But that is really irrelevant, since they already
had kilns capable of those temperatures. Bret Hinsch's original post stated
that the West was so far behind the East in kiln technology, and the only
way they could have achieved the necessary temperatures to fire true
porcelain was with solar lenses. We all know that the East Asians had very
sophisticated, efficient sequential-firing kilns very early on. But at the
time hard-paste porcelain was developed in the west the Germans did have
efficient stoneware kilns suitable for firing porcelain.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Khaimraj Seepersad on mon 26 feb 01
Hello to All ,
Vince ,
as I told Earl Brunner , this response was not to you . I receive
ClayArt as a digest , often in pieces . Remember I do not live
in the US .
The response to Larry's letter simply went out before your
first response to me . His arrived before yours .
I am publicly responding to this so there will be no confusion
any one needed clarification need only read all of the
- Solar Kilns -and Firing Porcelain with Solar Lenses e-mails.
Khaimraj
* Please read my post carefully -
re:Firing Porcelain with Solar Lenses
Hard Paste is defined by Fournier and Norton -
at over 1350 deg.c.
This is not just my opinion .
-----Original Message-----
From: vince pitelka
To: CLAYART@LSV.CERAMICS.ORG
Date: 26 February 2001 0:16
Subject: Re: SOLAR KILNS?
>> > What Vince said was incorrect - you must read the whole chapter 9 of
>> > Ceramic Masterpieces - Kingery and Vandiver
>> > - to see where Vince makes his errors .
>
>Khaimraj -
>I guess I'll have to keep an eye out for that book in order to see where I
>made my errors. As I have stated, I am fascinated to find out that
>scientists trying to develop true porcelain really were melting things with
>solar lenses, and that they had achieved temperatures high enough to fire
>porcelain by this method. But that is really irrelevant, since they
already
>had kilns capable of those temperatures. Bret Hinsch's original post
stated
>that the West was so far behind the East in kiln technology, and the only
>way they could have achieved the necessary temperatures to fire true
>porcelain was with solar lenses. We all know that the East Asians had very
>sophisticated, efficient sequential-firing kilns very early on. But at the
>time hard-paste porcelain was developed in the west the Germans did have
>efficient stoneware kilns suitable for firing porcelain.
>Best wishes -
>- Vince
>
>Vince Pitelka
>Appalachian Center for Crafts
>Tennessee Technological University
>1560 Craft Center Drive, Smithville TN 37166
>Home - vpitelka@dtccom.net
>615/597-5376
>Work - wpitelka@tntech.edu
>615/597-6801 ext. 111, fax 615/597-6803
>http://www.craftcenter.tntech.edu/
Gary Elfring on mon 26 feb 01
>If this was in fact such a great cost effective way do make a living
>with pottery we would be doing it by now.
>
>The fact that people have tinkered with a concept doesn't automatically
>make the concept practical.
To figure out whether or not it will work and whether it is practical,
just ask an engineer.
For practical- unless you live in the artic or antartic, I doubt you will
get more than 12 continuous hours of sunlight on the longest day of the year.
(The first few hours and the last few are worthless- the sun angle is too
low.) Can you do all your firing in 12 hours or less?
Will it work at all? If I remember correctly the average solar energy influx
on earth is about 1 watt per square meter (I could be wrong, but this is
easy to
look up). You can easily look up your electric kiln requirements.
Let's try a simply and very small test kiln. The 6" x 6" x 6" test kilns take
120 volts at 20 amps. That's 2,400 watts. (20 x 120) If solar radiation is 1
watt per square meter, you need 2,400 square meters of reflecting material
(assuming 100% reflection), or a mirror 49 x 49 meters in size. All for a
6" test
kiln. (And running under a 100% assumption, which is obviously wrong. You
should
probably double the size of that mirror for the sake of conversion errors.)
A mirror that is 150 by 150 feet, all to run a 6 inch test kiln for 12
hours max,
doesn't sound too practical.
-gary elfring-
the horsehair and feather king
Gary Elfring on mon 26 feb 01
>If this was in fact such a great cost effective way do make a living
>with pottery we would be doing it by now.
>The fact that people have tinkered with a concept doesn't automatically
>make the concept practical.
Ignore my first post. Here are the correct numbers.
To figure out whether or not it will work and whether it is practical,
just ask an engineer.
For practical- unless you live in the artic or antartic, I doubt you will
get more than 12 continuous hours of sunlight on the longest day of the year.
(The first few hours and the last few are worthless- the sun angle is too
low.) Can you do all your firing in 12 hours or less? Then you what to worry
about clouds?. Finally, your location effects the amount and angle of radiation
which effects how much can be used.
Will it work at all? The average solar energy influx in North America is about
200 watts per square meter. You can easily look up your electric kiln
requirements.
Let's try a simply and very small test kiln. The 6" x 6" x 6" test kilns take
120 volts at 20 amps. That's 2,400 watts. (20 x 120) If solar radiation is 200
watt per square meter, you need 12 square meters of reflecting material
(assuming 100% reflection), or a square mirror 10 feet on a side. All for a
6" test
kiln. But you automatically loose at least 35% of the energy in North
America because the average incident angle is too low (35% of the light
bounces away). And this assumes the
mirror reflects 100% of the light {it won't} and that you capture 100% of
the light
in your 6" square {you won't}.
For a practical kiln size, say a 1 foot square cube, you need 4 times the
energy, hence 4 times the mirror size. As you can see, this quickly becomes
impractical.
-gary elfring-
the horsehair and feather king
Bret Hinsch on mon 26 feb 01
Dear Vince,
Europeans trying to figure out how to make hard paste porcelain faced two
different problems - how to compound the body and also how to reach a high
enough temperature. Bottger's most famous achievement was figuring out the
composition of porcelain. But this was only half the story. He also made
major improvements in his kilns that apparently made them capable of firing
to higher temperatures than anything previously seen in Europe.
I'm no expert on German ceramic history. Maybe someone somewhere in Germany
was firing to a high enough temperature for porcelain and the people trying
to make porcelain just weren't aware of it. But the people who were trying
to make porcelain considered firing temperature a big problem. Solar lenses
were used in a few early experiments to reach the high temperature needed
for porcelain. As far as I know, they only fired test tiles this way. Then
Bottger improved his kilns and they could make porcelain reliably in a kiln.
The book "The Arcanum" goes into great detail about all of this, and it's
also a great read. Anyone interested in the history of European ceramics
will love it.
Bret in Taipei
>From: vince pitelka
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: SOLAR KILNS?
>Date: Sun, 25 Feb 2001 23:09:42 -0600
>
> > > What Vince said was incorrect - you must read the whole chapter 9 of
> > > Ceramic Masterpieces - Kingery and Vandiver
> > > - to see where Vince makes his errors .
>
>Khaimraj -
>I guess I'll have to keep an eye out for that book in order to see where I
>made my errors. As I have stated, I am fascinated to find out that
>scientists trying to develop true porcelain really were melting things with
>solar lenses, and that they had achieved temperatures high enough to fire
>porcelain by this method. But that is really irrelevant, since they
>already
>had kilns capable of those temperatures. Bret Hinsch's original post
>stated
>that the West was so far behind the East in kiln technology, and the only
>way they could have achieved the necessary temperatures to fire true
>porcelain was with solar lenses. We all know that the East Asians had very
>sophisticated, efficient sequential-firing kilns very early on. But at the
>time hard-paste porcelain was developed in the west the Germans did have
>efficient stoneware kilns suitable for firing porcelain.
>Best wishes -
>- Vince
>
>Vince Pitelka
>Appalachian Center for Crafts
>Tennessee Technological University
>1560 Craft Center Drive, Smithville TN 37166
>Home - vpitelka@dtccom.net
>615/597-5376
>Work - wpitelka@tntech.edu
>615/597-6801 ext. 111, fax 615/597-6803
>http://www.craftcenter.tntech.edu/
>
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Iveragh Ceramics on wed 28 feb 01
Vince,
The story or myth in Europe is that this person was an alchemist
who was involved in using solar rays to melt various minerals/rocks and
mixtures of these. European royalty supposedly loved and collected fine
porcelain from Asia, but no one knew the body recipe, it was the ingredients
of the body that the alchemist stumbled upon, he was then taken to the
castle of the local big-wig and made to reproduce his recipe and this was
supposedly the start of European porcelain. Believe it or believe it not.
Obviously if pots were to be made from this they would have to be fired in a
conventional kiln capable of reaching high temperatures, which, as you
state, they obviously had.
Hope this clears things up a little.
Regards,
Bob Hollis
----- Original Message -----
From: "vince pitelka"
To:
Sent: Monday, February 26, 2001 5:09 AM
Subject: Re: SOLAR KILNS?
> > > What Vince said was incorrect - you must read the whole chapter 9 of
> > > Ceramic Masterpieces - Kingery and Vandiver
> > > - to see where Vince makes his errors .
>
> Khaimraj -
> I guess I'll have to keep an eye out for that book in order to see where I
>
Logan Oplinger on thu 1 mar 01
Bruce and All,
We have been firing kilns with solar energy in stored form for hundreds (1000's?) of years. What has changed over time is the form in which that energy has been made available, as wood, coal, oil/gas, and indirect conversion to electricity. All of these have made the energy available for later use in concentrated form "on demand", which is probably the most effective/efficient way considering the intermittent process of ceramic production. IMHO wood is the most eco-friendly because it is renewable, and as long as what is used is replaced by replanting, no additional burden is added to the atmospheric load of carbon dioxide. However, where and what to replant do become issues when considering the environment in total.
Direct conversion of solar energy to electricity should be considered as an alternate method, but only as an end result after of our efforts to convert solar energy for use by the general population are successful in terms of convenience and cost.
Logan Oplinger
---- you wrote in part:
....
> For those who wish to consider the use of a solar kiln, I suggest that you
> first define what you mean by the term. Do you want to use solar radiation
> directly with a concentrating device, such as lenses or mirrors, or do you
> want to collect solar radiation over a longer period of time to be used on
> demand for firing a kiln?
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Larry Phillips on fri 2 mar 01
Logan Oplinger wrote:
>
> We have been firing kilns with solar energy in stored form for hundreds (1000's?) of years. What has changed over time is the form in which that energy has been made available, as wood, coal, oil/gas, and indirect conversion to electricity.
Well, in that case, why not just say that we have been using hydrogen
fusion to firte our pots? Hmmmm?
--
Procrastinate now!
http://24.113.44.106/larry/
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