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Dear Huck</div>
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Glad you noticed that comparison. </div>
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There are several problems:</div>
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The methods used to rate the stoves are not the same, even the WBT ones do not used the same calculations. </div>
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The high power metrics are not reported per liter of water placed on the stoves but per litre left after boiling which introduces a high variability even if the protocol is the same. </div>
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The three low power metrics are simply not valid measures of performance. </div>
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The cleanest stoves are the Mongolian coal stoves which are not reported at all even though the results are available. They are deep into Tier 4. Read the intro to the document for comments. </div>
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Progress in better burning stoves in the past year is 'major'. The new versions of the WBT report significantly lower performance than earlier versions for the same stove which means the earlier ones are over-rated. </div>
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The list is perhaps best used as a 'general idea' indicator. There are stoves that are not gasifiers that perform very well so don't rule them out, OK?</div>
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Regards </div>
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Crispin </div>
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BBM 2B567CC3</div>
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<div><b>From: </b>Huck Rorick</div>
<div><b>Sent: </b>Wednesday, October 15, 2014 17:12</div>
<div><b>To: </b>stoves@lists.bioenergylists.org</div>
<div><b>Reply To: </b>Discussion of biomass cooking stoves</div>
<div><b>Subject: </b>[Stoves] tier 4 stoves</div>
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<p class="x_MsoNormal">Hi All,</p>
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<p class="x_MsoNormal">I am puzzled by some of what I read about performance of stoves. For example, I saw this summary report from “Stove Performance Inventory”, Oct 2012, Berkeley Air Monitoring Group. Which shows no biomass stoves meeting Tier 4 goals
and well performing gasifiers in Tier 3 for emissions. </p>
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<p class="x_MsoNormal">From Stove Performance Inventory, Oct 2012, Berkeley Air Monitoring Group.</p>
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<p class="x_MsoNormal">Then I read that the InStove institutional rocket stove achieves Tier 4 in all categories except for Tier 3 in High Power PM. See chart:</p>
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<p class="x_MsoNormal">I realize this is an institutional stove and we can’t expect the same performance from a small family size stove, but it still seems surprising.</p>
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<p class="x_MsoNormal">Have any smaller rocket stoves come close to this?</p>
<p class="x_MsoNormal">Natural draft gasifiers?</p>
<p class="x_MsoNormal">What is the best gasifiers have been able to achieve?</p>
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<p class="x_MsoNormal">As an aside it seems that few stoves are tested with the same measures or criteria making it hard to know which are actually doing better.</p>
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<p class="x_MsoNormal">Huck</p>
<p class="x_MsoNormal" style=""><span style="font-size:12.0pt; font-family:"Arial","sans-serif"; color:#400040">Huck Rorick</span><span style="font-size:12.0pt; font-family:"Times New Roman","serif""></span></p>
<p class="x_MsoNormal"><span style="font-size:12.0pt; font-family:"Arial","sans-serif"; color:gray">Executive Director<br>
Groundwork Institute<br>
2640 Silvercrest Street<br>
Pinole, CA 94564<br>
Phone: 510-222-4111<br>
email: </span><span style="font-size:12.0pt"><a href="mailto:huckrorick@groundwork.org"><span style="font-family:"Arial","sans-serif"; color:blue">huckrorick@groundwork.org</span></a></span><span style="font-size:12.0pt; font-family:"Times New Roman","serif"; color:gray"><br>
</span><span style="font-size:12.0pt; font-family:"Arial","sans-serif"; color:gray">Website:
</span><u><span style="font-size:12.0pt; font-family:"Arial","sans-serif"; color:blue"><a href="http://www.groundwork.org"><span style="color:blue">www.groundwork.org</span></a></span></u><span style="font-size:12.0pt; font-family:"Arial","sans-serif"">
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