I decided to make a quick and dirty comparison test. I have a Fluke thermocouple Model 52.
I took a 3 oz cup and placed it inside a 5 oz cup, bottom to bottom. Then I put a hole and ran the thermocouple wire inside, trying to center it inside the smaller cup.
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Some ASCII-Art, how's that for a throw-back! The exclamation is where the thermocouple is.
I hung this upside down (bottoms up) outside the window adjacent to the roof of the garage (from where I took the picture).
When the sun came out, the peak temperature on the Fluke was 115.8F.
I immediately ran to the basement computer where the WDTU is running for the Envoy 8x. The Davis sensor inside the thermo-siphon was at 94.9F.
I then exported the database (today's) to Excel and plotted it. The maximum temperature was 96.8F.
It seems that the siphon is doing something, since the simple inverted cups were about 10F higher.
The siphon temperature is about 10F higher than the ISS.
I'll attach the plot.
Standing inside near this window, you can feel the heat coming in off the roof when the sun is out.
Greg H.
