<div dir="ltr">Dear Dr. Karve, Ron:<br><br>A dumb question: if the purpose of insulation is heat retention, would it help to create a class of heat retention and/or heat transfer options separate from stove types as such? <br><br>Heating water for bathing and laundry is one thing. I had wood- and charcoal "samovars" with an exhaust in the middle when I was growing up. I have also seen samovars in Afghanistan and probably Mongolia. <br><br>Smaller-scale samovars or tiffins with insulation keep the food warm and save energy otherwise needed to re-heat the food. <br><br>Enameled cast-iron cooking pots got me thinking last night - for some types of cooking, are they more energy-efficient (ignoring the energy in making cast iron and enameling it)? <br><br>Another, far out, idea of energy storage is dried cooked foods, whether dried by solar/wind, or hot gases, or some other means. <br><br>For heat transfer, I think there was some discussion here a few months ago about steam, fuel- or solar-based. <br><br>The overall point may well be that considering the diversity of cooking and water heating needs, we must stop boiling water or any "standard" stove performance protocols based on metrics that are irrelevant to cooks. <br><br>Inasmuch as the distinction between cooking, water heating, and stove heating stoves is blurry - many cookstoves serve space warming purpose needed (i.e., in wintry weather) - some matrix of fuel quality, stove, utensil type, insulation, heat transfer may help classify stoves better than what Paul found in the World Bank report a couple of years ago. <br><br>Nikhil</div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><font face="georgia, serif">------------------------------------------------------------------------<br>Nikhil Desai</font></div><div><span style="font-family:georgia,serif;font-size:small">(US +1) 202 568 5831</span><font face="georgia, serif"><br><i>Skype: nikhildesai888</i><br></font><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Thu, Nov 16, 2017 at 4:02 AM, Anand Karve <span dir="ltr"><<a href="mailto:adkarve@gmail.com" target="_blank">adkarve@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><p class="MsoNormal">Dear Ron.</p>
<p class="MsoNormal">The gadget described by me was designed to be used as a
water heater, using charcoal as fuel. People normally use a water heater of 20
to 40 litre capacity. These traditional water heaters generally work on the
principle of a samovar. Because people
use agricultural waste or garden waste as fuel, the traditional water heater
produces a lot of smoke, and it is therefore operated outdoors. But in order to
avoid its getting stolen, one brings it into the house after use and carries it
out again in the next morning. We therefore developed a water heater which uses
charcoal as fuel. Because charcoal burns without smoke, our device can be used
indoors. But because indoor space is a constraint, I designed a heater having a
relatively small water pot and a small stove. One starts the fire in the
evening, before going to bed. The hot water in the pot gets transferred by heat
siphon process into an insulated overhead tank. The charcoal fire does not need
tending and it gets automatically extinguished when the charcoal in the stove
has burned itself out. When one gets up in the morning, one has a barrel full
of hot water. We made various models
based on this idea. In some, the water pot was of aluminum and in some others we
used a stainless steel pot. The jacket
was insulated with rock wool, which is fire proof. The jacket enclosed the
flame completely and extended for about 10 mm above the pot. The gap between the water container and the
jacket ranged from 10mm to 15mm. We never used a jacket without insulation. For
ease of testing, we used a LPG stove. The efficiency always ranged between 80
and 90 percent. Two Japanese students from Nihon University worked with us as
interns for about a month in July/August, 2017. They did the actual work of
fabricating and testing under my guidance. I am 81 and too old and infirm to
work with my hands. This water heating device
is still in its prototype stage.</p>
<p class="MsoNormal">Yours Karve </p></div><div class="gmail_extra"><span class=""><br clear="all"><div><div class="m_3026154683648749141gmail_signature" data-smartmail="gmail_signature">***<br>Dr. A.D. Karve<br><br>Chairman, Samuchit Enviro Tech Pvt Ltd (<a href="http://www.samuchit.com" target="_blank">www.samuchit.com</a>)<br><br>Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)<br></div></div>
<br></span><div><div class="h5"><div class="gmail_quote">On Thu, Nov 16, 2017 at 1:44 AM, Ronal W. Larson <span dir="ltr"><<a href="mailto:rongretlarson@comcast.net" target="_blank">rongretlarson@comcast.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div>AD:</div><div><br></div><div><span class="m_3026154683648749141m_6792769940647522447Apple-tab-span" style="white-space:pre-wrap"> </span>Thanks. I can now see why this 90% value is possible with a bath water heater. One could fairly easily separate the losses associated with the two water containers - by using an electric immersion heater on the larger unit. So my interest is mainly on the smaller unit and its jacket. What is the gap separation and height and the radial thickness dimension of the jacket? That should be transferable to regular cooking geometries. Might the 10% thermal loss have about 8% in this part of the heating geometry? Any idea what the losses would have been if there were no jacket?</div><div><br></div><div>Ron</div><div><div class="m_3026154683648749141h5"><div><br></div><br><div><blockquote type="cite"><div>On Nov 15, 2017, at 12:16 AM, Anand Karve <<a href="mailto:adkarve@gmail.com" target="_blank">adkarve@gmail.com</a>> wrote:</div><br class="m_3026154683648749141m_6792769940647522447Apple-interchange-newline"><div><div dir="auto">Dear Ron,<div dir="auto">I fabricated a bath water heater in which the water was heated in a 3 litre container. The container was sealed at the top with only the inlet and outlet jutting out of the top. The inlet and outlet were joined to an insulated plastic barrel of 40 litre capacity. The container to be heated was surrounded by an insulated </div><div dir="auto">jacket. Starting temperature of water was 28 C. The pot was heated on a LPG stove. Hot water got transported into the insulated barrel by heat siphon. Experiment was stopped when water in the barrel reached 50C. Calories used were calculated on the basis of reduction in weight of LPG cylinder. Calories utilised were calculated on the basis of rise in water temperature in the barrel and volume of water in the barrel. Experiment was repeated for 5 days, one expt a day. </div><div dir="auto">Yours Karve</div></div><div class="gmail_extra"><br><div class="gmail_quote">On 15-Nov-2017 09:32, "Ronal W. Larson" <<a href="mailto:rongretlarson@comcast.net" target="_blank">rongretlarson@comcast.net</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div>AD: cc list</div><div><br></div><div><span class="m_3026154683648749141m_6792769940647522447m_-625511835013774717Apple-tab-span" style="white-space:pre-wrap"> </span>The 90% number here is extraordinarily high. Ca you give more details?</div><div><br></div><div>Ron</div><div><br></div><div><br></div><br><div><blockquote type="cite"><div>On Nov 14, 2017, at 4:29 PM, Anand Karve <<a href="mailto:adkarve@gmail.com" target="_blank">adkarve@gmail.com</a>> wrote:</div><br class="m_3026154683648749141m_6792769940647522447m_-625511835013774717Apple-interchange-newline"><div><div dir="ltr"><h2><span style="font-size:12pt;font-family:Calibri,sans-serif;font-weight:normal;background-image:initial;background-size:initial;background-origin:initial;background-clip:initial;background-position:initial;background-repeat:initial">Dear Karolina,<span></span></span></h2><p class="MsoNormal">The pot, which is kept on the stove, should be provided with
a well insulated jacket which makes the flue gases pass through the gap between
the pot and its jacket. We obtained 90% efficiency with such pots, when tested on stoves using either LPG or charcoal. I am quite sure that it would work in the case of biogas too. The
practical difficulty with this solution is that one has to have a jacket for every pot. </p><p class="MsoNormal">Yours</p><p class="MsoNormal">A.D.Karve</p></div><div class="gmail_extra"><br clear="all"><div><div class="m_3026154683648749141m_6792769940647522447m_-625511835013774717gmail_signature" data-smartmail="gmail_signature">***<br>Dr. A.D. Karve<br><br>Chairman, Samuchit Enviro Tech Pvt Ltd (<a href="http://www.samuchit.com/" target="_blank">www.samuchit.com</a>)<br><br>Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)<br></div></div>
<br><div class="gmail_quote">On Mon, Nov 13, 2017 at 12:51 PM, Karolina Hagegård <span dir="ltr"><<a href="mailto:karolinahagegard@gmail.com" target="_blank">karolinahagegard@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto"><div>Hi</div><div dir="auto"><br></div><div dir="auto">I'm currently in Kenya, trying to start up a biogas company:</div><div dir="auto"><br></div><div dir="auto"><a href="https://karolinabiogas.wordpress.com/present-project/" target="_blank">https://karolinabiogas.wordpre<wbr>ss.com/present-project/</a></div><div dir="auto"><br></div><div dir="auto">I'm having problems finding proper biogas stoves!</div><div dir="auto"><br></div><div dir="auto">Yesterday I had a meeting with a local stoves expert. He sells extremely efficient insulated stoves for firewood, or the husks of coconuts, or "any solid combustible material that you want to put in", and he also sells completely uninsulated biogas burners. So I asked if he wouldn't be interested in developing an insulated biogas stove for me, by the same principle as the firewood stove he had, and I'd be selling it together with my digesters. To my surprise, he wasn't!... He said that in his experience, gas needs lots of air, so you couldn't insulate it... Is it true? I told him I'd think about it and get back to him.</div><div dir="auto"><br></div><div dir="auto">This morning, I googled, WITH quotation marks, "insulated biogas stove". There were no direct hits. I tried "insulated biogas cooker" and "insulated biogas burners" but still no hits...</div><div dir="auto"><br></div><div dir="auto">So how is it? Is it really true that you can't make an insulated biogas stove? What's the most energy efficient alternative I can go for?</div><div dir="auto"><br></div><div dir="auto">Most grateful for any advice!</div><div dir="auto"><br></div><div dir="auto">/Karolina</div><div dir="auto">Kenya</div><div dir="auto"><br></div></div>
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