[Stoves] Key differences of performance test protocols for household biomass cookstoves

[Otto Formo]

Dear Crispin,
 
I very much agree with you about the comparison among apples and oranges, which will not tell the whole story.
 
I consider agri- and forest-waste for "free", because the biomass are not utilized, any how.
Pellet production demand energy, which also has to be calculated into the total energy budget.
Woodchips also need some preparaition, but less.
Corn colbs need just man- or woman power, that`s all.
 
People, also seems to "forget" that to produce a TESLA, you need enegry both in the production line and to handle the waste materials, like batteries etc.
Nobody is mentioning to much about the "popular" catalysator for petrol cars, any longer. 
 
We realy have to look into the energy circle, before drawing to many conclutions and clear statements.
 
Enjoying the summer along the Baltic Sea, where they are focusing on woodchips and pellets for fuel.
 
Otto 
 
From: crispinpigott at outlook.com
To: stoves at lists.bioenergylists.org
Date: Sat, 5 Jul 2014 01:40:00 +0800
Subject: Re: [Stoves] Key differences of performance test protocols for	household biomass cookstoves

Dear Otto The claim, if presented as a comparison between the energy that goes into a power station compared with the fuel burning in a stove is an apples and oranges comparison because the energy that went into making the wood is not considered. It is presented of course in a patently misleading manner as if an open fire is ‘efficient’. It depends on how much of the tree is wasted in the field, how much is lost during ignition and how much is left smouldering after the cooking is finished. It is this sort of thing that gives stoves projects a bad name. As for time to boil, a Vest stove will boil water at a rate of 3 minutes per litre measured from the time of ignition, i.e. light the match and start the clock, and it will boil 2.5 litres in 7.5 minutes. That is much faster than anything on the chart. I wonder why it is not included as it has been available for 10 years. The Peko Pe has been available much longer. The way to really misrepresent the performance of a stove in terms of its fuel consumption is to calculate the energy used in the fire rather than the energy that was standing in the forest when the fuel cycle started. Then compare it with the energy in the ground that needs to be dug up to make electricity. The numbers quote for an induction cooker are clearly wrong. Yixiang Zhang and I looked at every model available in a Chinese mall and none were less than 88% efficient. So even the worst of them, from, power station to hot water, is more efficient that the most perfectly operated open fire not counting forest losses and burnout. And that’s enough of that.Crispin From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Otto Formo
Sent: Saturday, July 05, 2014 1:02 AM
To: Stoves Bioenergylist
Subject: Re: [Stoves] Key differences of performance test protocols for household biomass cookstoves Dear stovers,
 
I do not know what kind of gasifier unit the Low Tech Magazine, are refering to and have tested, but for sure, the ND Peko Pe, will boil 2,5 L of water in less than 10 mins, using wood pellets from Pine. (Woodchips or almost any type of dry biomass, moisture content less than 15%, will do the same).
That should indicate a different result, mentioned in the diagram, where the gasifier came third.
 
The efficiency of the Peko Pe, tested in Copenhagen in 1996, varied from 25 - 29%, depending of the type of fuel.
 
How the Rocket stove can reach a therminal efficiency up to 54%, is to good to be true.
 
Have a Nice summer.
 
Otto
 Dear Crispin - thank you for sharing this,   Have you (or anyone else) by any chance read this article http://www.lowtechmagazine.com/2014/06/thermal-efficiency-cooking-stoves.html  It a real mind turner to say the least.... I would be very interested to hear some of your thoughts on this matter. To quote one of the opening paragraphs -  ''In fact, an electric cooking stove is only half as efficient as a well-tended open fire, while a gas hob is only half as effective as a biomass rocket stove. And even though indoor air pollution is less of an issue with modern cooking stoves, research indicates that pollution levels in western kitchens can be surprisingly high.''  The author then follows that article up with this one - http://www.lowtechmagazine.com/2014/07/cooking-pot-insulation-key-to-sustainable-cooking.html What do you think? I think I need to double my forestry efforts. 

Kind Regards,  Teddy 
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