[Stoves] Stove Definition - controllability

Frank Shields frank at compostlab.com
Fri May 3 13:02:49 CDT 2013


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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