[Stoves] Advocacy action: ask the GACC to stop promoting the WBT

[Crispin Pemberton-Pigott]

Dear Paul

>FUEL is not the same as ENERGY.

With question of science there are interchangeable things: fuel is a proxy for energy and convertible. If I say I need 20 MJ of energy I can calculate how much rice hull that is, or oak.

Same in reverse. I am not sure what you are getting at about word games. These matters are taken seriously.

>And I accept that wood that has been turned into gases and charcoal is no longer wood.

Good so far.

>But the Char is still with significant ENERGY, and that is what needs to be stated.

Good so far, the same can be said for wood. It has significant energy and it also needs to be known to make an efficiency calculation.

>If CREEC is following the same terminology as the other testing centers, so be it.

The terminology comes in the form of the WBT spreadsheet and protocol document. They were just following orders. It is not their fault.

>The line should be labeled "energy efficiency."

Ouch, no it is not. Any common understanding of energy efficiency (name any device or vehicle) has no subtractions in the denominator. There are 3200 references in the EU standards to ‘energy efficiency’ and they refer to the delivered work and the total input.

>You wrote:
The appropriate metric for that [cooking] is the 'cooking efficiency', which considers the amount of fuel needed and the cooking accomplished.
>Why would you say FUEL?????

Because tests are conducted with a fuel. Any fuel can be converted into a quantum of energy. Fuel efficiency and energy efficiency are the same thing, The calculation is done using Joules.

>We all know that people do not cook with FUEL.

All people cook with what is termed an ‘energy carrier’. They cannot contain ‘energy’ in their hands. There are many energy carriers. (It is a surprisingly common term).

>They cook with the ENERGY that comes from the fuel.

Technically they cook with some of the energy that is released by from the fuel.

>TLUD stoves (char making stoves) do not release all of the energy from the fuel.

No stove burning solid fuel releases all the energy from the fuel. Please recall what the goal of the reporting metric is: most people ask for the fuel efficiency which can be represented exactly using the energy efficiency (or ‘overall energy efficiency’ if you like).

You are looking for a metric that communicates the benefits of a char making stove. That benefit is the char itself – you guys have said that repeatedly. So…report the char. Characterise it. It is a benefit. It does not alter the fuel efficiency/energy efficiency number for that stove which is also the cooking efficiency if it is a cooking stove.

I am very clear that Ron wants it to result in a ‘higher number’ so the energy efficiency, in terms of how much fuel is needed to operate the stove, appears better than it is. I have understood that from the start.  You cannot mis-report the fuel consumption. You can report the fuel consumption and also the char production. But you can’t weasel the energy in the char into a better fuel consumption number, because making char does not reduce the amount of fuel consumed. That is not complicated.

>As I said, "playing with words."  I refer ONLY to the topic of char that needs to be taken into account.

Taken into account to report what? The fuel consumption?  You have agreed it is not the same as ‘fuel’. Fine. Then it is not going to raise the fuel efficiency. Now what? What are you going to call this char energy? I have proposed calling it the char energy retention efficiency (CERE) so that a stove which produces more char per input of fuel while maintaining the cooking ability gets rewarded with a higher CERE number. If it also cooks better it can have a higher cooking efficiency.

If it cooks better should it get a higher CERE number? Of course not. The char production didn’t increase.

>And you said that I would agree that knowing "heat transfer efficiency" woud not be helpful to me.   I disagree.   It is certainly useful to know how well a stove gets the heat transferred into the pot.

I said it would not help you find a metric that reports the efficiency of char production. Of course the HTE is helpful, but not to regulators or buyers, any more than the efficiency of second gear in a car. It is the whole package that delivers the fuel efficiency number.

I also suggest you could report the market value of the input fuel and the output char. If the ratio of char/wood is greater than 1, it is a money maker. That is a highly contextual market value but still, it would drive sales if there is a benefit.

Please read the formulas again where cooking and char production are combined.
(B+C)/A

Give it a name, ask that it be reported. How about ‘Energy Benefit’? That could be used to report space heating as well because some stoves do that. For the on in the example the Energy Benefit would be 75%, and the breakdown of that would follow: 12.5/25/37.5

That gives the buyer a clear indication of what they are getting. Maybe they want to see that middle number a lot higher and are not worried about cooking (cooking efficiency is not important in Kyrgyzstan – the heat tea water only, most of the time.)

Remember you have to clearly define what constitutes ‘char’ as it is only a portion of the residual solids. ‘Opinion’ cannot factor into it much. It is hard to regulate opinion.

Regards
Crispin

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