[Stoves] Anticipating future markets for stoves and fuels

Crispin Pemberton-Pigott crispinpigott at gmail.com
Fri Jun 24 10:28:41 CDT 2011


Dear Jeff

I read the Evans-Jackson book a few months ago when I was talking to Daniel Roggema. It is pretty interesting. Our conversation was in part about technical inaccuracies in the book and how they affected the performance of the heaters.

I will do a small calculation today to see what the drafts and pressure are like in a small, taller version of the heat exchanger. If there is a chance of it working in a 2.8 metre high space, it could be used to make a condensing heat exchanger as long as it can be drained. As described, it will be condensing, but it does not really have a formal way to deal with the moisture.

Consider this: the coal burned in Ulaanbaatar is 25 to 35% moisture, and there is a fairly high H2 content in the fuel as well, making additional moisture. The tests we ran in 2010 generated 620 g of water for each kg of coal burned (water in the stack). If the temperature drops below 100 C there is a black, sticky mess running down the chimney to deal with if combustion is poor. 

The Korean TLUD briquette stove (there are about 15,000 of them in the city) had an exit temp of 88 C and a lot of 'liquid problems'. 

So, if the condensation can be piped to a holding tank, it can be dealt with. With the new stoves, the water is quite clean, actually. There is just so much of it. The 'heating wall stoves' (basically high mass chimneys) are in fact condensing heat exchangers and a notorious for moisture issues as you can imagine - about 450 litres of water accumulate in them each month!

Regards
Crispin

++++++++

One of the greatest minds in bench heating is clearly Ianto Evans. He and Leslie Jackson wrote the book entitled "Rocket Mass Heater." One of my favorite reads. That was going to be one of my projects but because of a time shortage it was replaced by a store bought Bucket-A-Day.

Ref.:
<http://www.rocketstoves.com/>


Regards,

Jeff





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