[Stoves] condensing...

[Kevin]

Dear Rolf
----- Original Message ----- 
From: "Energies Naturals C.B." <energiesnaturals at gmx.de>
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Wednesday, May 15, 2013 4:06 PM
Subject: [Stoves] condensing...


>
> yes, right, the % you gain from condensing dwindles with inlet pressure, 
> which in "simple" systems tends to be low, though.
>
> But there is the very apreciated side effect of condensing to obtain 
> clean, demineralized feeding water.
> In many areas, water is limy (carbonates) or contains malot of  iron or 
> other minerals.
> That's why condensing the exhaust makes sense beyond energy gaines.

# That would be a bad way to go. Feeding highly mineralized water to the 
boiler and evaporating off the steam would result in the minerals being 
deposited inside the boiler. That can lead to boiler damage and/or 
explosions.. In such an area where water is heavily mineralized, a "Boiler 
feedwater Treatment Plant" would be required.

Best wishes,

Kevin
>
> Rolf
>
>
> On Wed, 15 May 2013 15:16:22 -0300
> "Kevin" <kchisholm at ca.inter.net> wrote:
>
>> Dear Bryce
>>
>> Thanks for the feedback.
>>
>> "Condensing" is simple in concept. Simply pass the steam exhausted from 
>> the engine through a "condenser." :-) A "Condenser" is a heat exchanger 
>> that is cooled with air or water, and it creates a vacuum, enabling the 
>> piston to extract more work from the steam.
>>
>> For example, if the temperature of the water leaving the condenser was 
>> about 140 F, the vacuum in the condenser would be about -12  psig, and 
>> effectively, 50 psig steam would be as 'powerful" as 62.3 psig steam.  A 
>> problem with the Green steam engine could be that when the steam was 
>> expanded enough to get the vacuum, there could be leakage of air in past 
>> the O-rings, and a de-aerator would then be required to remove the air. 
>> Additionally, you also need a boiler water feed pump, operating under 
>> vacuum, to recover the water from vacuum of the condenser, and lift it up 
>> to boiler pressure of 50 psig.
>>
>> They say, as you quote below:
>> " There are numerous reasons that this design is considerably more 
>> efficient than standard historical steam engines."
>> There are also numerous reasons why condensing systems are not used on 
>> small systems, two reasons of which are cost and complexity.
>>
>> Best wishes,
>>
>> Kevin
>>   ----- Original Message ----- 
>>   From: Bryce L Nordgren
>>   To: Discussion of biomass cooking stoves
>>   Sent: Wednesday, May 15, 2013 12:48 PM
>>   Subject: Re: [Stoves] Green Steam Engine
>>
>>
>>
>>
>>
>>   On Wed, May 15, 2013 at 9:25 AM, Kevin <kchisholm at ca.inter.net> wrote:
>>
>>     Dear Bryce
>>
>>     I couldn't find his claim for 24% efficiency, but it seems to be very 
>> high. I calculate that the useable energy in the steam is less than 3%.
>>
>>   Yeah, for a website with only three pages, it sure needs work. The 
>> claim is on the "Licensing" page. I wasn't trying to review his claims, 
>> because that's a bit out of my niche. I just wanted to see where the 
>> provided numbers took us.
>>
>>   The 24% figure was for recondensing the steam around the boiler. I 
>> can't fathom how that works since the exhaust steam is at 1 atm. How 
>> would the boiler be cold enough to recondense 1 atm steam to liquid if it 
>> has to be hot enough to make steam at 4-9 atm?
>>
>>   Here's the snippet:
>>
>>
>>       When the steam is simply exhausted to atmosphere while running a 
>> generator, for example, efficiency is relatively low; in the area of 15%. 
>> When the exhaust is condensed and recycled back to the boiler, the 
>> efficiency is around 24% to 30%. When the exhaust is condensed through a 
>> heat exchanger whereby the condensation process is used fully by heating 
>> water, space and distilling water, for example, the efficiency can be in 
>> the 70% range.
>>       In addition to the potential for efficient energy use and 
>> production, the designs' simplicity, economy and weight more than 
>> justifies its utilization. It is important to note that utilizing free or 
>> cheap fuel makes efficiency less important. There are numerous reasons 
>> that this design is considerably more efficient than standard historical 
>> steam engines.
>>
>>
>>
>>
>>
>> ------------------------------------------------------------------------------
>>
>>
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>
>
> -- 
> Energies Naturals C.B. <energiesnaturals at gmx.de>
>
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