[Gasification] The Age of Steam

[Thomas Reed]

Dear Dean and All:

Steam is indeed an incredible heat transfer medium and it was widely 
used in the 19th Century, not so much now.  There is a lot of technology 
associated with boilers that none of us know.  Among other things it is 
necessary to remove all air from the steam before it achieves high 
rates, and boiling non-distilled water will eventually clog the system 
with mineral. 

So, by all means let's use steam for cooking and heating, but there are 
downsides. 

TOM REED             BEF    (Back from a 3 week trip to LA-SF)



Dean Still wrote:
> Dear Martin,
>
> In India I saw steam being used to cook huge amounts of rice and sauce in a
> monastery. The heat transfer efficiency would be very high I would imagine
> because all of the heat from the steam would go into the pot of food as the
> steam changes phase in the water in the pot. 
>
> It takes 1,000BTU's to turn a pint (a pound) of water to steam. 
>
> Somehow we need to make the steam. So I guess that the question is: Can
> steam generation and transport be accomplished with higher efficiency than
> direct contact with the cooking vessel? Really good wood stove/pot
> combinations get about 40 to 50% of the heat into the pot.
>
> I guess that a correctly sized flame could flash water to steam but will the
> difference in heat transfer efficiency be worth the trouble? Can we describe
> the energy used in this kind of system?
>
> I am intrigued because the only solar cooker that has impressed me operated
> on this principle but it used a lower temperature phase change liquid...not
> water, maybe ammonia if I remember correctly...
>
> Best,
>
> Dean
>
> -----Original Message-----
> From: stoves-bounces at listserv.repp.org
> [mailto:stoves-bounces at listserv.repp.org] On Behalf Of frank at compostlab.com
> Sent: Saturday, September 16, 2006 3:32 PM
> To: Boll, Martin Dr.; stoves at listserv.repp.org; 'Jeff Davis'
> Cc: 'Frans Peeters'
> Subject: Re: [Stoves] Wasted heat
>
> Martin,
>
> My interest lie in places that have little wood, no electricity and smoky
> stoves in the kitchen. Like the ares of Nepal in the recent post from Tom. 
> The need to first heat up a stove until it is hot and maintain that
> temperature, then heat up the iron pot and keep that hot and whatever heat
> is
> left gets to go into the water - seems like such a waste. Having a stove the
> size of a bread box with a flame to boil about 25 mls of water that is
> constantly being replaced and having the steam go directly into the pot
> could
> work very well with Frans idea. Frying bread (like in the picture) will need
> plan B. 
>
> Years ago (~20 ) we had such a homemade set-up in the lab that we used to
> steam distill for nitrogen determinations. It blew steam directly into the
> ~40mls water we wanted to distill. It got to boiling temperature much faster
> than if we had the heat directly under the flask. If I can find it I may be
> able to see how it is set up and run some tests.  
>
> Frank
> Soil Control Lab
> www.compostlab.com
>
>
>
>
>
>
> On Sat, 16 Sep 2006 21:07:41  0200, Boll, Martin Dr. wrote
>   
>> Dear Jeff
>> Just a hint to your word:
>>
>> "What if we put a pot made of thin metal and filled with
>> water and potatoes into an insulated box."
>>
>> Frans Peeters is very interested in the subject of no wasting heat by
>> cooking. He operates with insulated vessels and modern heating-
>> technic to transfer heat to the potatoes or other vegetables. He 
>> makes calculations and cooking-tests with a Duard-pot (thermos-
>> bottle principle). It is impressive. He wrote about that already in 
>> the stoves-list some time ago. And he told me, that his dishes taste 
>> very well.
>>
>> Martin
>>
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>
>
> --
>
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