I have already noticed cars slowing as they go by to stare at my contraption.

zelph wrote:Yes, hope you can try it.....sounds very scientific. I like dual purpose solar stoves
Pnw.hiker wrote:zelph wrote:Yes, hope you can try it.....sounds very scientific. I like dual purpose solar stoves
They've been doing this for centuries in India to make ice, according to an old professor I know. Heat moves by convection, conduction and radiation. If you insulate the water from convection and conduction, and direct radiation out into space, you can get 10 or 20 degrees below ambient. You need very still air though, and clear skys.
In September 1999, we placed two funnels out in the evening, with double-bagged jars inside. One jar was on a block of wood and the other was suspended in the funnel using fishing line. The temperature that evening (in Provo, Utah) was 78º F. Using a Radio Shack indoor/outdoor thermometer, a BYU student (Colter Paulson) measured the temperature inside the funnel and outside in the open air. He found that the temperature of the air inside the funnel dropped quickly by about 15 degrees, as its heat was radiated upwards in the clear sky. That night, the minimum outdoor air temperature measured was 47.5 degrees - but the water in both jars had ICE. I invite others to try this, and please let me know if you get ice at 55 or even 60 degrees outside air temperature (minimum at night). A black PVC container may work even better than a black-painted jar, since PVC is a good infrared radiator - these matters are still being studied.
I would like to see the "Funnel Refrigerator" tried in desert climates, especially where freezing temperatures are rarely reached. It should be possible in this way to cheaply make ice for Hutus in Rwanda and for aborigines in Australia, without using any electricity or other modern "tricks." We are in effect bringing some of the cold of space to a little corner on earth. Please let me know how this works for you.
Return to “Stoves With Character”
Users browsing this forum: No registered users and 2 guests