<font color="#000099"><font face="verdana,sans-serif">Thanks Crispin for, as usual, giving sane advice. The old kerosene refrigerators worked on the principle of ammonia/water/helium mixture. BTW this refrigerator was designed by Albert Einstein in early 1920s. He and Silzard had almost 30 patents on it!</font></font><div>
<font color="#000099"><font face="verdana,sans-serif"><br></font></font></div><div><font color="#000099"><font face="verdana,sans-serif">The disadvantage of this device was that it was continuous and had quite a complex geometry. We need to charge our system in one or two hours from the heat so that it provides cooling for 24 hours!</font></font></div>
<div><font color="#000099"><font face="verdana,sans-serif"><br></font></font></div><div><font color="#000099"><font face="verdana,sans-serif">Garrett's system is quite poor in COP besides being extremely noisy!</font></font></div>
<div><font color="#000099"><font face="verdana,sans-serif"><br></font></font></div><div><font color="#000099"><font face="verdana,sans-serif">All the best.</font></font></div><div><font color="#000099"><font face="verdana,sans-serif"><br>
</font></font></div><div><font color="#000099"><font face="verdana,sans-serif">Anil<br></font></font><br><div class="gmail_quote">On Fri, Jan 18, 2013 at 10:09 AM, Crispin Pemberton-Pigott <span dir="ltr"><<a href="mailto:crispinpigott@gmail.com" target="_blank">crispinpigott@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Anil<br>
<br>
Is it not true that modern paraffin fridges use heat to flex a metal compressor?<br>
<br>
Perhaps a better question is, 'How does a modern paraffin-powered fridge work?'<br>
<br>
The physics of it must be quite optimised by now. They are available as alternative power in South Africa. It might be much more expensive than you would guess, but they make large fridges that work on that system.<br>
The two other methods I can think of are thermo-acoustic refrigeration which can be quite simple and can have efficiencies similar to that of an air compressor (45%) as well as thermoelectric coolers which are used in recreational vehicles.<br>
<br>
There is a free downloadable computer programme available from Los Alamos Lab for the design of thermo-acoustic refrigeration units. Prof Steve Garrett, who sometimes can be found at ETHOS, wrote it +20 years ago. It will save you a great deal of work if you want to resign one.<br>
<br>
SCORE is working on one attached to a stove, and has been for several years. I haven't seen it work yet though.<br>
<br>
In operation you heat a sealed tube off centre and have cooling near the heating point. It rattles a high pressure wave back and forth. One end gets cold, like, -100 C. It is a form of Stirling engine, actually.<br>
<br>
Regards<br>
<span class="HOEnZb"><font color="#888888">Crispin<br>
</font></span><div class="HOEnZb"><div class="h5">-----Original Message-----<br>
From: nari phaltan <<a href="mailto:nariphaltan@gmail.com">nariphaltan@gmail.com</a>><br>
Sender: "Stoves" <<a href="mailto:stoves-bounces@lists.bioenergylists.org">stoves-bounces@lists.bioenergylists.org</a>><br>
Date: Fri, 18 Jan 2013 09:49:49<br>
To: Discussion of biomass cooking stoves<<a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a>><br>
Reply-To: Discussion of biomass cooking stoves<br>
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Subject: [Stoves] Need help in designing a small refrigerator for rural huts.<br>
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</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><font face="arial, helvetica, sans-serif" color="#330099">Nimbkar Agricultural Research Institute (NARI)<br>Tambmal, Phaltan-Lonand Road<br>P.O.Box 44<br>
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