[Stoves] Price of bottled gas
Philip Lloyd
plloyd at mweb.co.za
Sat May 4 19:17:27 CDT 2013
Paul Oliver says " Here in Vietnam bottled gas costs more than $21.00 US per
bottle. There is
no distribution problem here at all."
The question is - why does a 5kg bottle of gas cost $21? What is the price
breakdown? What is the markup between the refinery gate and the street? LP
Gas should be priced approximately at the thermal equivalent of gasoline.
Less than 2 gallons of gasoline for $21? Something is wrong!
What we found was that there were so many middlemen in the original
distribution chain that indeed we were being asked to pay $18 for 5kg. By
addressing the various factors in the cost buildup, we were able to reduce
that to about $10 - at which point it was more than competitive with the
alternative fuel, paraffin. Then, of course, the existing distributors
started complaining - and worse (but that is what competition is all about)
Hope that helps!
Prof Philip Lloyd
Energy Institute
Cape Peninsula University of Technology
PO Box 652, Cape Town 8000
Tel:021 460 4216
Fax:021 460 3828
Cell: 083 441 5247
-----Original Message-----
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Sent: 04 May 2013 08:00
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Today's Topics:
1. Re: Stove Definition - controllability (Frank Shields)
2. Re: Stove Definition / High-Low energy-cooking (Boll, Martin Dr.)
3. Re: Stove Definition - controllability (Crispin Pemberton-Pigott)
4. Re: Stove Definition - controllability (Lanny Henson)
5. Re: Stove Definition - controllability (Paul Olivier)
6. Re: the price of bottled gas (Anand Karve)
7. Re: the price of bottled gas (Paul Olivier)
8. The price of bottled gas (Philip Lloyd)
9. What makes a stove desirable? (Philip Lloyd)
10. Re: The price of bottled gas (Paul Olivier)
11. Re: What makes a stove desirable? (Sujoy Chaudhury)
12. Re: Stove Definition - controllability (Crispin Pemberton-Pigott)
----------------------------------------------------------------------
Message: 1
Date: Fri, 3 May 2013 11:02:49 -0700
From: "Frank Shields" <frank at compostlab.com>
To: "'Discussion of biomass cooking stoves'"
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition - controllability
Message-ID: <00ca01ce4828$6cec72d0$46c55870$@compostlab.com>
Content-Type: text/plain; charset="utf-8"
Dear Crispin and stovers,
<snip>
If I ask for a maximum power of X and ask for a demonstration that it can be
controlled to X/4 is that reasonable as a minimum standard of proof?
Thanks
Crispin
The ability to cut off air or reduce fuel and still run at optimum with no
smoke is directly related to stove box shape, construction material,
placement of air and controls etc. Its something that if we can find one
stove having a good turn down ratio then we can get all stoves to do it. We
need to find out the physical properties that effect the movement of heat
etc. This is the job of the scientist going beyond the WBT. I see another
ten step white paper ?? : )
Also;
Testing stoves to determine efficiencies is challenging due to the
complexity of how we are going about doing it. There are only two energy
measurements needed, Carbon and hydrogen (dry weight (dw)). We need to know
the grams of carbon and the grams of hydrogen (not water hydrogen) that we
place into the stove. How water effects the stove is in a group along with
cold air, heat transfer, utensil material etc. that drains heat from the
task. Grams carbon X 0.3491 + grams Hydrogen X 1.1783 = HHV in kJ/g of fuel
units is the energy going into the stove. The Carbon and hydrogen (dw) left
over after the Task is energy not used. So
((CX0.3491)+(HX1.1783))-((CX0.3491)+(HX1.1783)) / task is efficiency. I
like the idea of measuring the solid materials. That is the fuel going in
and the left over material dragged out of the stove and watered and oven
dried when the task is completed. There are only the two elements to
measure, carbon and hydrogen. Carbon is easy but hydrogen is a challenge. We
have the $70k USD equipment that is a pain to use and includes lots of
upkeep and training. I suggest we *try very hard* to see if we can justify
not including hydrogen in the analysis. Or to estimate the hydrogen from the
carbon value or look up tables as good enough. Then we only have carbon to
test and I think there are simple ways we can come up with to do that.
Cellulose is 44% carbon and 6% hydrogen. That is 15.2 energy given for C and
only 7.07 for hydrogen
Char left over has < 1% hydrogen and 80+ % carbon.
If this seems like a good approach we need a simple and good carbon test.
Regards
Frank
Thanks
Frank Shields
BioChar Division
Control Laboratories, Inc.
42 Hangar Way
Watsonville, CE 95076
(831) 724-5422 tel
(81) 724-3188 fax
<mailto:frank at biocharlab.com> frank at biocharlab.com
www.controllabs.com
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Message: 2
Date: Fri, 3 May 2013 22:42:36 +0200
From: "Boll, Martin Dr." <boll.bn at t-online.de>
To: "erin at trmiles.com" <erin at trmiles.com>
Cc: "stoves at lists.bioenergylists.org"
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition / High-Low energy-cooking
Message-ID: <80EA4345-F8DC-48FD-A297-C5497CD46819 at t-online.de>
Content-Type: text/plain; charset="us-ascii"
Erin,
You hit the point!
Your proposal to combine a "normal-high-energy-stove" with a RHC (Retained
Heat Cooker)
( I call it now ) as a _combined cooking system_ you touch the same point
I mentioned years before from another point of view.
You hit the energy saving aspect very well. As to use the "hot gas fire"
further for other use.
Let me underline your statement by my old statement:
__We cannot turn down a "normal-stove" so much, as we have to, to use the
simmering stage or better the low-temperature-stage to finish the cooking
process.___
All turning down is so less possible that the simmering-/low-temperature-
process is done with oversized energy-use. - If heat-isolation was done by
doing that process as good as possible, this process would be overheated.
I propose to call this second stage of cooking, reached by simmering or
low-heat-cooking, the "maturing-process". This implicates that there is no
more "real cooking" in the sense of boiling. And we can achieve it by a RHC
or an "activated-RHC" , as I would call a normal RHC with an extra
"energy-push" , given once by an heat-accumulator (( hay-box anno 1800 two
bricks)) or continuous by an extra minimal Flame, ( could be a tea-candle
-about 80 Watts)
We could call a normal stove just a stove and the second type a
maturing-heater (if you would like an abbreviation: a MH :-) )
When we really want to save energy:
It needs, for a big number of "whole" cooking-processes, the two different
cooking processes. And so it needs as well the normal stove (which can
easily be stopped or further used for other purpose) as well as the MH.
Mind:
- Even a custom gas-burner cannot be turned down so much that it can do the
maturing-process, when the pot is properly heat-isolated.
It even reaches not the process-perfection in minimizing the admitted heat
when the pot is not isolated; how could it do this when the pot was good
isolated??
Kind Regards
Martin
Message: 5
Date: Thu, 2 May 2013 16:10:35 -0700
From: "Erin Rasmussen" <erin at trmiles.com>
To: <rongretlarson at comcast.net>, "'Discussion of biomass cooking
stoves'" <stoves at lists.bioenergylists.org>, "'Lanny
Henson'"
<lannych at bellsouth.net>
Subject: Re: [Stoves] Stove Definition
Message-ID: <014d01ce478a$41680c80$c4382580$@com>
Content-Type: text/plain; charset="utf-8"
The EcoKalan project in the Phillipines is using a "magic box" cooker with a
rocket stove http://eco-kalan.com
I see no reason why you can't do the same thing with a char making stove.
Getting a starch or bean started on a gasifier stove, and then using the
remaining gasifier energy to finish your breakfast while the cooker is
saving you from using your coals to finish cooking your dinner, seems
reasonable.
Erin
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Message: 3
Date: Fri, 3 May 2013 21:11:42 +0000
From: "Crispin Pemberton-Pigott" <crispinpigott at gmail.com>
To: "Stoves" <stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition - controllability
Message-ID:
<2122433424-1367615502-cardhu_decombobulator_blackberry.rim.net-1195609066-@
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Dear Frank
I am not in any position to say how people turn down their fires. By that I
mean this is a performance based approach, not a prescription in any way.
There are good reasons why people use an open fire. One is that the fire is
very controllable.
I will address the efficiency determination separately. One thing at a time,
though I agree with your HHV number the pure carbon. I think the H2 number
you gave is the LHV (117 MJ/kg).
So I am proposing that we segregate cooking appliances into functional
categories with BASIC characterisations for each. They are of course driven
by the customers and what they think when they buy something.
A BBQ (barbie, braai) is a category of appliance that is largely use for
roasting and grilling. It usually has very little power control with the
food being raised or lowered, covered or not as a means of control.
A kettle is a water heater that shuts off automatically if it is electrical.
Is that available for LPG or wood pellets or ethanol? Why not? Maybe no one
asked.
Many people boil a small quantity if water, up to perhaps 2 litres. Cecil
has identified this as a 'class' of cooking activity. Heating tea in the
evening or morning is common. Sometimes people use LPG for this even if they
rarely use it for anything else. This a task highly suited of a small stove
that requires no attention and has zero controllability save being turned on
and off.
Translate that into larger units for heating 5 or 10 or 20 litres of water
at a time. None of these require turn down. But none of them are 'cooking
stoves'.
The requirement, literally, for cooking is a controllable heat source. So
the question is on the floor: how much control is enough to be a minimum?
Regards
Crispin
>From BB9900
-----Original Message-----
From: "Frank Shields" <frank at compostlab.com>
Sender: "Stoves" <stoves-bounces at lists.bioenergylists.org>
Date: Fri, 3 May 2013 11:02:49
To: 'Discussion of biomass cooking stoves'<stoves at lists.bioenergylists.org>
Reply-To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition - controllability
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Message: 4
Date: Fri, 3 May 2013 18:58:35 -0400
From: "Lanny Henson" <lannych at bellsouth.net>
To: "Discussion of biomass cooking stoves"
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition - controllability
Message-ID: <3234AC5D9ECF4C7F94ED94B237946591 at main>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
The minimum control would be enough to prevent food from over cooking and
to turn up the heat to a point necessary to perform the cooking task.
----- Original Message -----
From: "Crispin Pemberton-Pigott" <crispinpigott at gmail.com>
To: "Stoves" <stoves at lists.bioenergylists.org>
Sent: Friday, May 03, 2013 5:11 PM
Subject: Re: [Stoves] Stove Definition - controllability
> Dear Frank
>
> I am not in any position to say how people turn down their fires. By that
> I mean this is a performance based approach, not a prescription in any
> way. There are good reasons why people use an open fire. One is that the
> fire is very controllable.
>
> I will address the efficiency determination separately. One thing at a
> time, though I agree with your HHV number the pure carbon. I think the H2
> number you gave is the LHV (117 MJ/kg).
>
> So I am proposing that we segregate cooking appliances into functional
> categories with BASIC characterisations for each. They are of course
> driven by the customers and what they think when they buy something.
>
> A BBQ (barbie, braai) is a category of appliance that is largely use for
> roasting and grilling. It usually has very little power control with the
> food being raised or lowered, covered or not as a means of control.
>
> A kettle is a water heater that shuts off automatically if it is
> electrical. Is that available for LPG or wood pellets or ethanol? Why not?
> Maybe no one asked.
>
> Many people boil a small quantity if water, up to perhaps 2 litres. Cecil
> has identified this as a 'class' of cooking activity. Heating tea in the
> evening or morning is common. Sometimes people use LPG for this even if
> they rarely use it for anything else. This a task highly suited of a small
> stove that requires no attention and has zero controllability save being
> turned on and off.
>
> Translate that into larger units for heating 5 or 10 or 20 litres of water
> at a time. None of these require turn down. But none of them are 'cooking
> stoves'.
>
> The requirement, literally, for cooking is a controllable heat source. So
> the question is on the floor: how much control is enough to be a minimum?
>
> Regards
> Crispin
> From BB9900
>
> -----Original Message-----
> From: "Frank Shields" <frank at compostlab.com>
> Sender: "Stoves" <stoves-bounces at lists.bioenergylists.org>
> Date: Fri, 3 May 2013 11:02:49
> To: 'Discussion of biomass cooking
> stoves'<stoves at lists.bioenergylists.org>
> Reply-To: Discussion of biomass cooking stoves
> <stoves at lists.bioenergylists.org>
> Subject: Re: [Stoves] Stove Definition - controllability
>
> _______________________________________________
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>
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>
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> http://stoves.bioenergylists.org/
>
>
>
> _______________________________________________________
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>
>
------------------------------
Message: 5
Date: Sat, 4 May 2013 07:31:30 +0700
From: Paul Olivier <paul.olivier at esrla.com>
To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition - controllability
Message-ID:
<CAOreFvaVxFDSpPT8A_F859yDwCEXzJJ7oB_4L-=tjnz3VHVNyw at mail.gmail.com>
Content-Type: text/plain; charset="windows-1252"
Josh,
Thanks so much for that paper dealing with peanut shell biochar. This is a
good example of the kind of research needed in giving value to peanut shell
biochar. In this study we see that the efficacy of peanut shell biochar for
removing TCE from water was comparable to that of activated carbon.
Activated carbon sells at a relatively high price, and now peanut shell
biochar can be used in place of this expensive commodity.
So let us imagine a small village in a developing country where peanuts are
grown. Along comes a company that installs a pellet machine and produces
peanut shell pellets. These pellets are given to household free-of-charge
in exchange for some of the biochar produced from these pellets. The
company does not have to set up a large kiln to make peanut shell biochar.
It only has to set up a pellet machine.
So in using a cook stove, a household has a gas that can be used in the
place of bottled gas, and it has a biochar that can be used in the place of
activated carbon.
Here in the highland area of Vietnam where I live, there are a lot of pine
trees. Minority people regularly chop down these trees to make charcoal,
leading to high levels of deforestation. Here again pellet machines could
be installed to make pine needle pellets that, when processed in cook
stoves, could easily take care of all household cooking needs. At the same
time, pine needle biochar has certain properties that rival those of
activated carbon.
We look far too much at the cook stove. We need to focus a lot more on fuel
preparation and biochar research.
Many thanks.
Paul
On Fri, May 3, 2013 at 8:13 PM, Josh Kearns <yeah.yeah.right.on at gmail.com>
wrote:
>
> Effects of pyrolysis temperature on soybean stover- and peanut
shell-derived biochar properties and TCE adsorption in water
> Author(s): Ahmad, M (Ahmad, Mahtab)[ 1 ] ; Lee, SS (Lee, Sang Soo)[ 1 ] ;
Dou, XM (Dou, Xiaomin)[ 2 ] ; Mohan, D (Mohan, Dinesh)[ 3 ] ; Sung, JK
(Sung, Jwa-Kyung)[ 4] ; Yang, JE (Yang, Jae E.)[ 1 ] ; Ok, YS (Ok, Yong
Sik)[ 1 ]
> Source: BIORESOURCE TECHNOLOGY Volume: 118 Pages: 536-544 DOI:
10.1016/j.biortech.2012.05.042 Published: AUG 2012
>
> Abstract: Conversion of crop residues into biochars (BCs) via pyrolysis
is beneficial to environment compared to their direct combustion in
agricultural field. Biochars developed from soybean stover at 300 and 700
degrees C (S-BC300 and S-BC700, respectively) and peanut shells at 300 and
700 degrees C (P-BC300 and P-BC700, respectively) were used for the removal
of trichloroethylene (ICE) from water. Batch adsorption experiments showed
that the TCE adsorption was strongly dependent on the BCs properties.
Linear relationships were obtained between sorption parameters (K-M and
S-M)and molar elemental ratios as well as surface area of the BCs. The high
adsorption capacity of BCs produced at 700 degrees C was attributed to
their high aromaticity and low polarity. The efficacy of S-BC700 and
P-BC700 for removing TCE from water was comparable to that of activated
carbon (AC). Pyrolysis temperature influencing the BC properties was a
critical factor to assess the removal efficiency of ICE from water. (C)
2012 Elsevier Ltd. All rights reserved.
>
>
> On Fri, May 3, 2013 at 12:45 AM, Paul Olivier <paul.olivier at esrla.com>
wrote:
>>
>> Crispin,
>>
>> I agree: it is hard to cook without controlling heat. Your call for a
level of control from 100% to 25% sounds reasonable.
>>
>> Let us take the example of someone using a direct combustion wood stove.
This person might start out at 25% and add on more wood to achieve 100%.
But it will take time to reach 100%, and it will also take time to reduce
heat back down to the original starting point of 25%, if need be.
>>
>> So it's not simply a question of being able to vary the amount of heat.
The more difficult question is how quickly and easily one can move to any
percentage point in between 25% and 100% heat.
>>
>> Trying to establish criteria by which to judge and compare stoves is
awfully complex. For example, so much depends on the type of fuel that is
available in a given area. The perfect stove might demand a perfect fuel,
and if this perfect fuel does not exist in a given area, one has to choose
from an array of imperfect stoves. The perfect stove might be too expensive
for a particular poor corner of our planet. So once again we have to choose
from an array of cheap and imperfect stoves.
>>
>> Funding agencies come along and demand criteria by which to judge
stoves. But I profoundly mistrust the role of funding agencies. They, with
massive inputs of capital from the outside, can easily distort the normal
evolution of cook stove technology in a given area. Many funding agencies,
for example, have come into Vietnam and dispensed 100's of millions of
dollars in areas other than cook stoves. At the end of the day, many of
them have accomplished virtually nothing.
>>
>> So I suggest that we should approach funding agencies with caution. In
my opinion, it's not so much the cook stove that needs funding. It's all
that comes before and after the cook stove. Fuel preparation needs funding
(the before), and biochar research needs funding (the after).
>>
>> Someone recently took one of my gasifier into Laos. In this area of
Laos, she noted an abundance of peanut shells. But due to its low bulk
density, the peanut shell has to be pelleted before it can be used as fuel
in my gasifier. At the same time, no one has done research on the
properties of peanut shell biochar.
>>
>> Funding agencies could subsidize, through affordable loans, the purchase
of pellet machines at the village level, and based on several scientific
studies they might conduct, they could point to the benefits of peanut
shell biochar when incorporated into the soil. The big priority in this
particular region of Laos is not the stove, but all that comes before and
after it.
>>
>> How easy it is to get exceptional results out of a stove, if the fuel is
uniform and predictable, and how easy it is for a poor family to pay for a
stove, if this family can sell or use the biochar it produces.
>>
>> Thanks.
>> Paul
>>
>>
>>
>>
>> On Fri, May 3, 2013 at 9:12 AM, Crispin Pemberton-Pigott <
crispinpigott at gmail.com> wrote:
>>>
>>> Dear Friends
>>>
>>>
>>>
>>> I would like to remind everyone that it is pretty important to a cook
to be able to control the fire in some manner. There are lots of precedents
so I won?t repeat them. I would like to have a minimum control exerted over
the cooking power in order to qualify as a ?cooking stove?. There are many
appliances which are used for heating water, showers (like the Geyser 2000
etc) or drying fish and so one and on. But in order to ?cook? the fire has
to be controllable.
>>>
>>>
>>>
>>> For an electric or gas stove this is fairly easy. In order to start
things off, what does everyone think about a turn down ration of 4:1 where
the turn down is ?willful? meaning it is controlled by the cook be either
removing fuel, controlling airflow or by some other means. The reason is
that stoves are appearing which definitely burn fuel and provide heat but
are not very controllable (or not at all controllable). While one car argue
that by brilliantly fuelling the stove in just the right manner a fire and
its burn can be exactly matched to a cooking need ? agreed this is possible
? but is it ?cooking??
>>>
>>>
>>>
>>> When sitting in the field with cooks it becomes obvious that most
cooking involves controlling the power at some point. How much control
should be applicable to a stove in order to qualify as a ?cooking stove??
>>>
>>>
>>>
>>> If I ask for a water heating stove, it would not have to have any
controllability at all ? it just needs to heat the water within a certain
time after which it can go out ? no one will mind. But if we want to
present a ?solution? (a cooking alternative to an open fire or sheltered
fire) it will have to be manageable ?to a certain extent?.
>>>
>>>
>>>
>>> Thus if someone says, ?Here is my new cooking stove,? I can say, ?Prove
it can cook.?
>>>
>>>
>>>
>>> If I ask for a maximum power of X and ask for a demonstration that it
can be controlled to X/4 is that reasonable as a minimum standard of proof?
>>>
>>>
>>>
>>> Thanks
>>> Crispin
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Stoves mailing list
>>>
>>> to Send a Message to the list, use the email address
>>> stoves at lists.bioenergylists.org
>>>
>>> to UNSUBSCRIBE or Change your List Settings use the web page
>>>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>>>
>>> for more Biomass Cooking Stoves, News and Information see our web site:
>>> http://stoves.bioenergylists.org/
>>>
>>>
>>
>>
>>
>> --
>> Paul A. Olivier PhD
>> 26/5 Phu Dong Thien Vuong
>> Dalat
>> Vietnam
>>
>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>> Mobile: 090-694-1573 (in Vietnam)
>> Skype address: Xpolivier
>> http://www.esrla.com/
>>
>> _______________________________________________
>> Stoves mailing list
>>
>> to Send a Message to the list, use the email address
>> stoves at lists.bioenergylists.org
>>
>> to UNSUBSCRIBE or Change your List Settings use the web page
>>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>>
>> for more Biomass Cooking Stoves, News and Information see our web site:
>> http://stoves.bioenergylists.org/
>>
>>
>
>
>
> --
> Josh Kearns
> PhD Candidate, Environmental Engineering
> University of Colorado-Boulder
> Visiting Researcher, North Carolina State University
>
> Director of Science
> Aqueous Solutions
> www.aqsolutions.org
>
> Mobile: 720 989 3959
> Skype: joshkearns
>
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
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>
> for more Biomass Cooking Stoves, News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
--
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam
Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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Message: 6
Date: Sat, 4 May 2013 06:30:18 +0530
From: Anand Karve <adkarve at gmail.com>
To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] the price of bottled gas
Message-ID:
<CACPy7Sc0xM0E5quEoKOs2wsRpM7FygaOJ6=+Q58vvn_yqY5SCw at mail.gmail.com>
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Dear Stovers,
As cooking energy, biogas can easily replace LPG or CNG. Biogas gives a
blue flame without smoke or soot, its flame intensity can be controlled at
will and turning it on or off is as easy as LPG. Our work showed back in
2003 that dung is not needed for biogas production and that material like
sugar, starch, cellulose, digestible protein and fats can all be used as
feedstock. In our city, waste flour, swept from the floor of a flour mill
is available for about US Cents 10 per kg. 3 kg flour give enough biogas to
replace one kg LPG costing US Cents 80 (subsidised price) or US$1.6
(unsubsidised price. If you have a few green leafy plants around your
house, or have access to the local vegetable market waste, 10kg fresh green
leaves (available for no cost) would yield enough biogas to replace about 1
kg LPG.
Yours
A.D.Karve
On Fri, May 3, 2013 at 4:53 PM, Paul Olivier <paul.olivier at esrla.com> wrote:
> CNN just ran a new clip about the partial lifting of subsidies for
> bottled gas in Egypt - major point of unrest among the Egyptian people.
> Also there is this from Reuters:
>
http://uk.reuters.com/article/2013/04/01/uk-egypt-gas-idUKBRE93005I20130401
>
> The price of bottled gas is a huge problem throughout most of the
> developing world. If we can design gasifiers or pyrolyzers that produce a
> gas that can compete with bottled gas, this will have profound economic
and
> political consequences.
>
> The first step in making this happen lies in preparing biomass, in all of
> its many forms, into a predictable fuel.
>
> Thanks.
> Paul Olivier
> --
> Paul A. Olivier PhD
> 26/5 Phu Dong Thien Vuong
> Dalat
> Vietnam
>
> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
> Mobile: 090-694-1573 (in Vietnam)
> Skype address: Xpolivier
> http://www.esrla.com/
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>
> for more Biomass Cooking Stoves, News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
>
--
***
Dr. A.D. Karve
Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
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Message: 7
Date: Sat, 4 May 2013 17:31:59 +0700
From: Paul Olivier <paul.olivier at esrla.com>
To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] the price of bottled gas
Message-ID:
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Dear A.D.
Making biogas from type 1 or type 2 waste is not ideal.
Please see:
https://dl.dropboxusercontent.com/u/22013094/Paper/Summaries/Alternative%20t
o%20Biodigestion.pdf
Paul
On Sat, May 4, 2013 at 8:00 AM, Anand Karve <adkarve at gmail.com> wrote:
> Dear Stovers,
> As cooking energy, biogas can easily replace LPG or CNG. Biogas gives a
> blue flame without smoke or soot, its flame intensity can be controlled at
> will and turning it on or off is as easy as LPG. Our work showed back in
> 2003 that dung is not needed for biogas production and that material like
> sugar, starch, cellulose, digestible protein and fats can all be used as
> feedstock. In our city, waste flour, swept from the floor of a flour mill
> is available for about US Cents 10 per kg. 3 kg flour give enough biogas
to
> replace one kg LPG costing US Cents 80 (subsidised price) or US$1.6
> (unsubsidised price. If you have a few green leafy plants around your
> house, or have access to the local vegetable market waste, 10kg fresh
green
> leaves (available for no cost) would yield enough biogas to replace about
1
> kg LPG.
> Yours
> A.D.Karve
>
> On Fri, May 3, 2013 at 4:53 PM, Paul Olivier
<paul.olivier at esrla.com>wrote:
>
>> CNN just ran a new clip about the partial lifting of subsidies for
>> bottled gas in Egypt - major point of unrest among the Egyptian people.
>> Also there is this from Reuters:
>>
>>
http://uk.reuters.com/article/2013/04/01/uk-egypt-gas-idUKBRE93005I20130401
>>
>> The price of bottled gas is a huge problem throughout most of the
>> developing world. If we can design gasifiers or pyrolyzers that produce a
>> gas that can compete with bottled gas, this will have profound economic
and
>> political consequences.
>>
>> The first step in making this happen lies in preparing biomass, in all of
>> its many forms, into a predictable fuel.
>>
>> Thanks.
>> Paul Olivier
>> --
>> Paul A. Olivier PhD
>> 26/5 Phu Dong Thien Vuong
>> Dalat
>> Vietnam
>>
>> Louisiana telephone: 1-337-447-4124 (rings Vietnam)
>> Mobile: 090-694-1573 (in Vietnam)
>> Skype address: Xpolivier
>> http://www.esrla.com/
>>
>> _______________________________________________
>> Stoves mailing list
>>
>> to Send a Message to the list, use the email address
>> stoves at lists.bioenergylists.org
>>
>> to UNSUBSCRIBE or Change your List Settings use the web page
>>
>>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>>
>> for more Biomass Cooking Stoves, News and Information see our web site:
>> http://stoves.bioenergylists.org/
>>
>>
>>
>
>
> --
> ***
> Dr. A.D. Karve
> Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>
> for more Biomass Cooking Stoves, News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
>
--
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam
Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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Message: 8
Date: Sat, 4 May 2013 12:56:15 +0200
From: "Philip Lloyd" <plloyd at mweb.co.za>
To: <stoves at lists.bioenergylists.org>
Subject: [Stoves] The price of bottled gas
Message-ID: <00a901ce48b5$ff8faed0$feaf0c70$@co.za>
Content-Type: text/plain; charset="us-ascii"
Paul Oliver commented " The price of bottled gas is a huge problem
throughout most of the
developing world."
Part of the problem is poor models of distribution. Locally, we are seeing
the entry of a supplier who a) has found a way of filling 5kg bottles
rapidly at a central plant and b) distributing them directly to the retailer
at minimal cost, with a growing chain of retailers chosen so that the
householder can resupply within 500m. The net result is a halving of the
street price of bottle gas, and it is now the cheapest way to cook.
The advantage of filling at a central plant is that safety is greatly
enhanced; and the discovery of a way of filling small cylinders rapidly
means high throughput and low costs. Most big bottlers of gas don't like
the really small cylinders because they couldn't fill them rapidly enough to
get throughput - it was cheaper (and far less safe) to refill them at the
retailers.
Regards to all
------------------------------
Message: 9
Date: Sat, 4 May 2013 12:56:15 +0200
From: "Philip Lloyd" <plloyd at mweb.co.za>
To: <stoves at lists.bioenergylists.org>
Subject: [Stoves] What makes a stove desirable?
Message-ID: <00b301ce48b6$03dfa800$0b9ef800$@co.za>
Content-Type: text/plain; charset="us-ascii"
Eric Rasmussen asked what "characteristics that make an improved stove, a
sexy, aspirational stove, a stove that women actually want, and use and
cherish, and beg to spend scarce resources to pay for."
If it helps, my experience in a really low income village may be worth
sharing. It was a recently established village, due to some social
upheavals, and the householders were at the very bottom of the economic
pile, <5% employment, reliant on social grants for survival. Most homes
were of corrugated iron supported on weak beams, and had ridiculous thermal
properties when you considered an environment where temperatures could go to
-8 deg C overnight in winter.
Coal was the primary cooking and heating fuel, with found wood and dung
subsidiary fuels, and a bit of paraffin. At the lowest income level, the
coal was burned in open braziers, which were usually lit in the late
afternoon outside where the smoke was lost to atmosphere; only when the fire
bed was reduced to a mass of glowing coals was it brought indoors and used
for the evening meal and to heat the home. Indoor air pollution was
terrible.
One of the first investments was a cast-iron stove of a wood-burning design
originating (I think) in the US in the 1870's. The patterns are still
around, and there is a thriving market in spare parts for this design. New
stoves could cost up to $800; a second-hand one cost at least $300. There
was an established microfinance scheme that allowed users to buy one for
only $10/month - apparently for ever! Certainly one user of an expensive
model was still paying after ten years.
The advantages were numerous - the fact that the stove had a chimney meant
far cleaner indoor air; you could cook, heat water, bake, heat the iron,
keep the home warm during the night, burn rubbish and, above all, invite
your friends to come and share in your success. It was this last which
emerged as almost the most important feature - possession of such a stove
declared your social status to the community.
This is just one example, and is not, of course, universally applicable. It
happens to be widespread where coal is readily available cheaply - within
about 150km of the coal mines. But it does illustrate how it is possible
that, if you can really meet people's needs, they will find a way to get
your appliance, however much it costs.
Regards to all
Philip Lloyd
Energy Institute
Cape Peninsula University of Technology
PO Box 652, Cape Town 8000
Tel:021 460 4216
Fax:021 460 3828
Cell: 083 441 5247
------------------------------
Message: 10
Date: Sat, 4 May 2013 18:28:02 +0700
From: Paul Olivier <paul.olivier at esrla.com>
To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] The price of bottled gas
Message-ID:
<CAOreFvbUbwhrLR0FExaXNFS4zboDDcqnCboDcGZXemWx_EzqFw at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Philip,
Here in Vietnam bottled gas costs more than $21.00 US per bottle. There is
no distribution problem here at all. Some households use up a bottle in
less than one month. When the monthly wage is not more than $120 US per
month, the situation is extremely dire.
In many parts of Vietnam, rice hulls and coffee husks are often dumped in
rivers and valleys. Sometimes they are uselessly burned as a means of
disposal. With the right type of stove, these agricultural residues put out
a beautiful blue flame that rivals that of bottled gas.
When we derive energy from fossil fuels, there is nothing of value left
behind. But when we gasify or pyrolyze biomass, a valuable biochar remains.
When incorporated into the soil, biochar promotes plant growth and
sequesters carbon.
Why derive energy from fossil fuels when we can get it from renewable
biomass?
Are you not, in any way, concerned about global warming?
Thanks.
Paul
On Sat, May 4, 2013 at 5:56 PM, Philip Lloyd <plloyd at mweb.co.za> wrote:
> Paul Oliver commented " The price of bottled gas is a huge problem
> throughout most of the
> developing world."
>
> Part of the problem is poor models of distribution. Locally, we are
seeing
> the entry of a supplier who a) has found a way of filling 5kg bottles
> rapidly at a central plant and b) distributing them directly to the
> retailer
> at minimal cost, with a growing chain of retailers chosen so that the
> householder can resupply within 500m. The net result is a halving of the
> street price of bottle gas, and it is now the cheapest way to cook.
>
> The advantage of filling at a central plant is that safety is greatly
> enhanced; and the discovery of a way of filling small cylinders rapidly
> means high throughput and low costs. Most big bottlers of gas don't like
> the really small cylinders because they couldn't fill them rapidly enough
> to
> get throughput - it was cheaper (and far less safe) to refill them at the
> retailers.
>
> Regards to all
>
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>
> for more Biomass Cooking Stoves, News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
--
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam
Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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Message: 11
Date: Sat, 4 May 2013 17:39:00 +0530
From: Sujoy Chaudhury <sujoy.chaudhury at gmail.com>
To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] What makes a stove desirable?
Message-ID:
<CA+ejjr5NJ6aY+M8bfizrgk1aj+YT0hju-ziwZFG4zeFBJ+jDXA at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Hi Philip
A very interesting conclusion- as people in business will say, it is not
always the costs that matter, it is the additional aspects over the primary
purpose that influence a purchase.
Thank you and regards to all
Sujoy Chaudhury
Kolkata, India
On Sat, May 4, 2013 at 4:26 PM, Philip Lloyd <plloyd at mweb.co.za> wrote:
> Eric Rasmussen asked what "characteristics that make an improved stove, a
> sexy, aspirational stove, a stove that women actually want, and use and
> cherish, and beg to spend scarce resources to pay for."
>
> If it helps, my experience in a really low income village may be worth
> sharing. It was a recently established village, due to some social
> upheavals, and the householders were at the very bottom of the economic
> pile, <5% employment, reliant on social grants for survival. Most homes
> were of corrugated iron supported on weak beams, and had ridiculous
thermal
> properties when you considered an environment where temperatures could go
> to
> -8 deg C overnight in winter.
>
> Coal was the primary cooking and heating fuel, with found wood and dung
> subsidiary fuels, and a bit of paraffin. At the lowest income level, the
> coal was burned in open braziers, which were usually lit in the late
> afternoon outside where the smoke was lost to atmosphere; only when the
> fire
> bed was reduced to a mass of glowing coals was it brought indoors and used
> for the evening meal and to heat the home. Indoor air pollution was
> terrible.
>
> One of the first investments was a cast-iron stove of a wood-burning
design
> originating (I think) in the US in the 1870's. The patterns are still
> around, and there is a thriving market in spare parts for this design. New
> stoves could cost up to $800; a second-hand one cost at least $300. There
> was an established microfinance scheme that allowed users to buy one for
> only $10/month - apparently for ever! Certainly one user of an expensive
> model was still paying after ten years.
>
> The advantages were numerous - the fact that the stove had a chimney meant
> far cleaner indoor air; you could cook, heat water, bake, heat the iron,
> keep the home warm during the night, burn rubbish and, above all, invite
> your friends to come and share in your success. It was this last which
> emerged as almost the most important feature - possession of such a stove
> declared your social status to the community.
>
> This is just one example, and is not, of course, universally applicable.
> It
> happens to be widespread where coal is readily available cheaply - within
> about 150km of the coal mines. But it does illustrate how it is possible
> that, if you can really meet people's needs, they will find a way to get
> your appliance, however much it costs.
>
> Regards to all
>
> Philip Lloyd
>
> Energy Institute
> Cape Peninsula University of Technology
> PO Box 652, Cape Town 8000
> Tel:021 460 4216
> Fax:021 460 3828
> Cell: 083 441 5247
>
>
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
>
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists
.org
>
> for more Biomass Cooking Stoves, News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
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Message: 12
Date: Sat, 4 May 2013 09:44:12 -0400
From: "Crispin Pemberton-Pigott" <crispinpigott at gmail.com>
To: "'Discussion of biomass cooking stoves'"
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Stove Definition - controllability
Message-ID: <005901ce48cd$79fcf6c0$6df6e440$@gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Dear Paul and Lanny and everyone else who is considering this matter
Paul O >I agree: it is hard to cook without controlling heat. Your call for
a level of control from 100% to 25% sounds reasonable.
This request for controllable heat is not originating from me speculating.
The feedback from the social science team in Indonesia is that the
controllability of the cooking power is a pre-requisite for acceptance. A
?cooking stove? has a definition supplied by the users, in other words. I
can relay to you the various opinions but I will filter them while trying
simultaneously to develop a test method for meeting their requirements.
There are several relevant points raise by Paul so I will base my reply to
everyone on this set of comments.
>Let us take the example of someone using a direct combustion wood stove.
This person might start out at 25% and add on more wood to achieve 100%. But
it will take time to reach 100%, and it will also take time to reduce heat
back down to the original starting point of 25%, if need be.
The analysis must remain cognizant of the uses to which the stove is put.
The time taken to increase or reduce the heat in the pot (which I will call
the ?cooking power? because it is the heat available to the cook inside the
pot) is not defined or restricted. The cooking power is different for
different meal types, and sometimes it varies during the preparation of a
single food. Rice is a good example, but only in some cases. In Central Java
rice is steamed which requires high cooking power and a high-medium power.
If the rice is not steamed it requires high power followed by a very low
power. We cannot say ?cook rice? and then decide if it is a good stove
because people cook rice in many different ways.
I am trying to set minimum standards which if not met, will mean the product
is ?not able to do that? or perhaps ?is not a cooking stove? though it could
do other tasks like heating water or space heating. Because of the minimum
demands of the end users, there is a need for some way of assessing the
controllable from the uncontrollable stoves.
>Trying to establish criteria by which to judge and compare stoves is
awfully complex.
Be that as it may, there is a job to be done and we have to start somewhere.
The best we can do is survey the opinions of the stove makers (you guys and
gals) so you know there is a minimum set of performance criteria that will
be applied when testing day comes. And it is coming soon.
>For example, so much depends on the type of fuel that is available in a
given area.
The fuel or fuels will be specified, for example teak. However if a
manufacturer has a stove that requires a particular fuel, they can say so
and it will be tested with that fuel. If you offer a sawdust stove, it will
be tested with sawdust. For example a stove may require wood pellets of 8mm
diameter with a moisture content under 10%. No problem, you can specify
that, and it is up to your company to try to make that fuel available.
Ethanol stove and fuel people do that all the time.
Better cooking solutions can include a specific fuel and it will be tested
using that fuel. Getting a ?passing grade? does not mean someone else will
develop the market. But the gatekeepers will have a pass/fail stamp on what
is a cooking stove. Reasonable, no? However it will also be started that for
a particular are the fuels available are xx and yy and zz. The test will be
conducted with those fuels; here is the baseline emission level from the
existing stoves. In many cases the manufacturer may not have the fuel so
they will have to take a guess and the stove tested a few times by the
rating laboratory to see how it performs and feedback given to the producer.
No problem. The point is to get better products.
>From the cooks? point of view, claiming that a stove can cook when it can?t
be used for most cooking tasks is misleading and the dissemination plan will
fail. Customers insist on a turn down ability. The discussion then turns to
?how much?, not ?whether that is a real need? or ?but my stove can?t do that
? make an exception?. The customer wants power control over the heat in the
pot. End of short story.
>The perfect stove might demand a perfect fuel, and if this perfect fuel
does not exist in a given area, one has to choose from an array of imperfect
stoves.
Fortunately this is not a contest to find the ?best stove? as the customers
will pass their opinion and even when shown a ?perfect? stove from the
inventor?s point of view, might reject it. ?Imperfect? is in the eyes of the
buyer.
>The perfect stove might be too expensive for a particular poor corner of
our planet. So once again we have to choose from an array of cheap and
imperfect stoves.
Again, fortunately, that is not for a regulator to decide. There is a big
broad market out there. People can sell what they want provided it meets
certain minimum criteria. Today we are talking about the turn down ratio
(TDR) and what constitutes a fair requirement for a minimum level of
repeatable control.
>Funding agencies come along and demand criteria by which to judge stoves.
Now this is an interesting point. A project can support whatever they want
and have project criteria that meet their own agenda ? like solar cookers or
pellet stoves or whatever else (like, 100% locally produced and so on). A
national regulator might set certain minimum performance standards but a
project may have much tighter criteria or higher expectations. That is up to
them and their project team.
>But I profoundly mistrust the role of funding agencies. They, with massive
inputs of capital from the outside, can easily distort the normal evolution
of cook stove technology in a given area.
Funding inappropriately can upset the production systems and destroy a lot
of businesses, but that may be the intention ? to get rid of a host of
really bad products and replace them with a major improvement. I can think
of a couple of cases. Trust? We are entitled to our opinions. The
government?s opinion matters most and they regulate. So what should the
minimum regulations say?
>Fuel preparation needs funding (the before), and biochar research needs
funding (the after).
I will restrict this to the turndown ratio. Fuel we can discuss later and in
relation to fuel standards, OK?
So, the demand, the requirement from the field is for a measure of control.
This is not the opinion of project people, funders, analysts and
technicians, it is from the customers who are supposed to be the
beneficiaries. No turn down, no sale.
Let?s say our target is 10 million homes. We survey the typical cooking
styles and ask the typical users their opinion and find that they use a TRD
during a typical week of 4:1. When setting a national standard for
performance the widest possible accommodation must be made so as not to
limit innovation, to provide for an array of cooking needs, and to still
provide a guarantee to the public that if it says ?Passed? it means
something real.
If we test a stove product that is designed for small pots in an urban
setting, it may have an upper power limit if 1.5 kW. That means it can
reasonably cook a smallish pot in a reasonable time. It is clear already how
to describe that so I will write it now:
The cooking experience is related to the time it takes to heat things.
Typical of this is boiling water ? a common task. Asking for input on the
matter, it seems that a 5 litre boiling time of 25 minutes is considered
?good?. To produce a boiling time of 25 minutes for 5 litres in a 400g pot
with a lid, 254mm in diameter on it takes a heat transfer rate of about 2
watts per sq cm. If you are not familiar with this approach, it means that 2
Joules enters the outer pot surface per second over the whole bottom of the
pot. The ?area? of the pot can be calculated from its outer diameter.
Heat enters a pot primarily through the bottom and nearly nothing enters
(net) from the side. The sides are in fact a source of net cooling almost
all the time. So the relationship is between the pot bottom and the fire. If
the heat getting into the pot (counting for the thermal mass of the pot as
well) reaches 2 watts per sq cm, it will have ?an acceptable cooking power?,
at least it will in Indonesian households, at least in Central Java, at
least in the homes we asked, at least that is what they said.
So starting with this as a concept to measure cooking satisfaction, we also
start with the figure of 2 watts/sq cm. For a 25 cm diameter pot it is 1 kW
gained by the pot, i.e. 1000 Joules gained per second, with the lid on. If
a stove can induce that much cooking power, the stove can be considered
?improved? or ?modern? or ?acceptable?, at least in that set of communities.
In other places the number may be different.
Given this heating rate, what then shall be the definition of a
?controllable fire?? With charcoal people turn down the air supply, remove
charcoal, splash on a little water or move the pot (is that cheating?).
There is a clear demand for controllability. How shall it be determined?
We can ask the operator to turn down the heat (by any means) and demonstrate
a cooking power of 1 watt per sq cm. That would be ? power. There is no
implication about how many kW the fire is, just that for a pot the
manufacturer says ?this stove can cook it?, it must be able to provide 2
watts per sq cm and it can turn it down to 1 watt.
Again we can ask that it be reduced to ? a watt per sq cm and see if it can
do that too. If all stoves claimed to be ?cooking stoves? can demonstrate
this level of control, no matter the size of the stove, we have a simple
rule that can apply to anyone?s product, for any stove size, and for any pot
size, even if it is a frying wok or a steaming pan.
I noted more than one comment that some stoves do not turn down well. That
is a fact and a reality for the inventor. If a stove can?t be turned down,
it will be rejected by the cooks we meet because they demand a minimum
turndown. They do not express it in watts, but I can translate. We measure
what they do and find out what the ?cooking power? is (as defined above)
then set a standard for the power per sq cm in the pot. If a stove is large,
it can ?properly cook? a larger pot. But it still gets the same minimum
power and performance test of a 50% and 25% power level, defined by the
expected cooking experience.
I am hoping that many of the people reading this list who do not usually
make comments will arise on this occasion and give some feedback on this
issue. If we are promoting cooking stoves, from the point of view of the
customers in your area, what constitutes a reasonable level of control over
the cooking power, below which they are not interested in buying it?
I am not directing developers as to how they control the cooking power, only
that the control has to be real ? i.e. sustained for 20 or 30 minutes ? and
that it cover a minimum range stated in a standard. We can set a level with
some permissible variability.
Stoves used for water boiling, continuous heat applications and so on which
do not require control can be classified as ?stoves?, but not ?cooking
stoves?. That again does not originate from my opinion but from the field
and is the opinion of the customers who we are trying to satisfy. They are
happy with water heating stoves, but for cooking are more demanding.
As a brief aside the use of LPG in Indonesia (another thread) is widely
promoted (and subsidised) however field research shows that nearly all
households that use LPG also use biomass to heat water. If the LPG price
rises many will return to biomass for more cooking tasks. LPG is highly
controllable ? more than 8:1 TDR. People like that.
Final proposition: Do you agree that products meeting the minimum standard
to be labelled an improved ?cooking stove? can be required to show the
product can deliver 2 watts per sq cm into a pot (as defined) ? which allows
the manufacturer to define the stove they think they can sell and pot sizes
it can cook ?properly?) ? and that the requirement for the stove to be
turned down for 20 to 30 minutes to 1 watt and 0.5 watts per sq cm ? for a
TDR of 4:1 ? are a reasonable minimum requirements?
Thanks everyone
Crispin
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