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Dear all,<br>
<br>
I have been subscribed to the list for only a few days, and am
pleasantly surprised by the relevance of the ongoing discussions,
especially since our NGO is also working on the temperature
management / insulation of household digesters.<br>
<br>
Let me introduce our projects. Our NGO, Initiative Développement
(ID), <a class="moz-txt-link-abbreviated" href="http://www.id-ong.org/cn">www.id-ong.org/cn</a> , has built in China more than 2500
household digesters in poorly developed areas. These are of the
Chinese fixed dome model, 10m3, and made of either brick/concrete,
or concrete alone. We are following up these digesters and their
users very closely, in particular since we certify the emission
reductions with Gold Standard and sell the ERs to further self-fund
our projects. This close monitoring allows us to detect and solve
ongoing technical problems, and to provide regular biogas trainings
and knowledge recycling for the households.<br>
<br>
We are now looking more closely at how to further improve the
management of our digesters, as well as the use of the slurry for
agriculture. For this purpose, we are designing a series of field
tests/experiments:<br>
* measuring the influence of a layer of organic insulating material
or compost, on top of the digester, on the temperature of the
content and the gas production<br>
* measuring the influence of different input mixes on the gas
production (pig/cow manure alone; manure + corn stalks; manure +
pine needles; manure + leftover tobacco leaves; these are the
substrates available locally)<br>
* testing the use of the slurry for soaking seeds: impact on
germination rate, shoot growth and diseases (test plots)<br>
* testing the use of the slurry for fertilising and spraying apple
trees: impact on tree health, action against pests&diseases,
tree nutrient uptake, apple yield (test plots)<br>
* testing the efficiency of an optimised mixed fertilisation plan
(biogas slurry+compost+mineral fertiliser) on corn, potato and
tobacco test plots<br>
<br>
We will implement these tests on our project sites in the
south-eastern province of Yunnan in China, with half a dozen
selected households. This represents a lot of work and follow-up in
remote areas, so we clearly won't reach the accuracy of a proper
research team. However, our goal is not to make research as such,
but instead:<br>
* to test the efficiency and practicality of methods developed
elsewhere and tune them to the local conditions<br>
* to use the experiments sites as hinges to spread adapted practices
within the communities, in particular by organising village meetings
and community trainings around the test sites<br>
<br>
If any of you would have advice or documentation relevant to our
projects/experiments, I would be more than happy to hear from you.
I'd also be glad to share our results with people interested.<br>
<br>
<br>
Furthermore, we are facing two urgent measurement issues:<br>
<br>
1 - how to measure the volume of biogas produced (or rather,
consumed by the user on their stove)? The gas indeed varies in
pressure, so that positive displacement flow meters (such as
diaphragm meters), are not suitable. What kind of system would you
advice to measure the gas flow out of a digester, that would be
compensated in pressure, or measure the actual mass flow of the gas?
Our typical daily production is in the 1m3 range.<br>
<br>
2 - temperature measurement: we would like to measure the
temperature within the digester with 0.5°C accuracy, and are looking
at thermistor (NTC) or pt100 measuring devices with a 3m long cable.
The probe could be introduced through the compensation chamber for
each measurement, or left in place depending on the cost. We've also
been thinking of using data-loggers. Could you advice cost-efficient
solutions? We're also wondering about the temperature layering
inside the digester? Can you suggest an upper limit on the
temperature gradient?<br>
<br>
Any advice would be welcome!<br>
<br>
<br>
Regards,<br>
<br>
Nicolas Borchers<br>
<br>
<br>
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<p style="margin-bottom: 0cm" lang="en-US"><b>Nicolas Borchers </b><font
face="WenQuanYi Zen Hei"><span lang="zh-CN">博石屹</span></font></p>
<p style="margin-bottom: 0cm" lang="en-US">Organic Farming Officer
<font face="WenQuanYi Zen Hei"><span lang="zh-CN">有机农业项目官员</span></font></p>
<p style="margin-bottom: 0cm"><br>
</p>
<p style="margin-bottom: 0cm">+86 159 2552 3303</p>
<p style="margin-bottom: 0cm" lang="en-US">Skype: nborchers</p>
<p style="margin-bottom: 0cm"><br>
</p>
<p style="margin-bottom: 0cm"><span lang="fr-CH"><b>Initiative
Développement – </b></span><span lang="fr-CH">China </span><font
face="WenQuanYi Zen Hei"><span lang="zh-CN"><font
face="SimSun"><span lang="zh-CN"><b>法国发起发展组织</b></span></font></span></font></p>
<p style="margin-bottom: 0cm" lang="en-US">402, B2, Fubang garden,
Shulin st., 650100 Kunming, Yunnan province, China </p>
<p style="margin-bottom: 0cm"><font face="WenQuanYi Zen Hei"><span
lang="zh-CN"><font face="SimSun"><span lang="zh-CN">云南省昆明市书林
街富邦花园</span></font></span></font><span lang="fr-CH">B</span><font
face="WenQuanYi Zen Hei"><span lang="zh-CN"><font
face="SimSun"><span lang="zh-CN">座</span></font></span></font><span
lang="fr-CH">2</span><font face="WenQuanYi Zen Hei"><span
lang="zh-CN"><font face="SimSun"><span lang="zh-CN">单元</span></font></span></font><span
lang="fr-CH">402</span><font face="WenQuanYi Zen Hei"><span
lang="zh-CN"><font face="SimSun"><span lang="zh-CN">室</span></font><font
face="WenQuanYi Zen Hei"><span lang="zh-CN">
</span></font><font face="SimSun"><span lang="zh-CN">邮编：</span></font></span></font><span
lang="fr-CH">650100</span></p>
<p style="margin-bottom: 0cm" lang="fr-CH">+86 (0)871 3181557</p>
<p style="margin-bottom: 0cm"><a href="http://www.id-ong.org/cn"><span
lang="fr-CH">www.id-ong.org/cn</span></a></p>
<p style="margin-bottom: 0cm"><br>
</p>
<p style="margin-bottom: 0cm"><span lang="fr-CH">Energy</span> <span
lang="fr-CH">Globe
Award 2009 and 2011</span></p>
<p style="margin-bottom: 0cm" lang="fr-CH">International
Solidarity
Award (HCCI) 2007</p>
<p style="margin-bottom: 0cm"><br>
</p>
<p style="margin-bottom: 0cm"><font color="#f8520a"><span
lang="en-US">Offset
your carbon emissions with ID – <a
href="http://www.id-ong.org/">www.id-ong.org</a></span></font></p>
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