The wind finally calmed and the OAT was 36 F so I assumed the ice would be well frozen. The water in the PVC cap was liquid but the box was 21.5F. I put the temperature probe in the water and it caused slushy ice to form immediately. Seems I had made super-cooled water.
Tonight I am going to try a copper plate with a center well which is painted flat black. The shiny copper was a complete failure.
Thursday, March 31, 2016
Friday, March 18, 2016
A slight haze last night with OAT of 43F. Box was at 30.5F but no ice. Seems I have gone as far as I can with my present setup. Will try and construct a continuous black plastic bottom. From the data it looks like rusted steel bight be my best bet. Better conduction and almost the same emissivity as the black PVC.
I wonder if higher sides might allow better cooling? The surface area of the base seems critical because when I tried dividing it in half, the results were worse.
I wonder if higher sides might allow better cooling? The surface area of the base seems critical because when I tried dividing it in half, the results were worse.
Thursday, March 17, 2016
Removed the fancy heat sink and made more ice at 42F OAT. The box interior was 26 F.
Thinking that the floor of the box should be a piece of rusted metal to act as a better conductor of the heat to a larger radiant surface.
Still see no use for the concept but it does make me question the concept of "white" roofs.
Thinking that the floor of the box should be a piece of rusted metal to act as a better conductor of the heat to a larger radiant surface.
Still see no use for the concept but it does make me question the concept of "white" roofs.
Wednesday, March 16, 2016
Update on experiment
16 March 2016
The high thin overcast has started to dissipate with the approaching high pressure.
The clearer skies have allowed better radiant cooling and the temperature dropped to 42 F last night. I had a small amount of ice on one of the black PVC pieces but none with the fancy radiant cooler. The interior of the box was 28 degrees with the OAT of 42. Only a small amount of ice formed which would imply that the temperature did not drop quick enough to allow for better ice formation. I am using a glass bowl as a control and it was 40 degrees.
I need to figure out a method of improving the heat transfer to dissipate the heat of fusion to produce faster freezing. It is interesting that the simple black PVC surface seemed to be better that the fancy carbon coated radiant fins of the computer CPU cooler. This may be an artifact of the quantity of water involved.
The high thin overcast has started to dissipate with the approaching high pressure.
The clearer skies have allowed better radiant cooling and the temperature dropped to 42 F last night. I had a small amount of ice on one of the black PVC pieces but none with the fancy radiant cooler. The interior of the box was 28 degrees with the OAT of 42. Only a small amount of ice formed which would imply that the temperature did not drop quick enough to allow for better ice formation. I am using a glass bowl as a control and it was 40 degrees.
I need to figure out a method of improving the heat transfer to dissipate the heat of fusion to produce faster freezing. It is interesting that the simple black PVC surface seemed to be better that the fancy carbon coated radiant fins of the computer CPU cooler. This may be an artifact of the quantity of water involved.
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