Chet:
The math was fine and it's all based on the fact that it takes 4.19 (Some say 4.18) Joules of energy to produce one Calorie of heat energy. I know math is not your strong suit so I suggest that you work with your friends on the thread to make a step-by-step template for yourself so you can simply punch in the numbers and get your results.
I am not sure what an "Ikea thermos mounted inside a 50 liter vessel" really means. Daemonbart seems to be implying a "30 liter thermos" in his posting, which I can't understand but like I said perhaps English is not his native language.
Your preliminary calculations were based on a single tick of your Kill-a-Watt meter and you may recall that I posted that the fewer ticks your Kill-a-Watt meter makes the less accurate it is. I suggested that your results should be based on at least 100 ticks of the Kill-a-Watt meter to be accurate. Perhaps you can come up with some kind of strategy to compensate or work around this issue with your associates on the thread.
Nor have I seen any attempt by anyone on the thread to deal with the issue of the thermal mass of the container itself. You are never just heating up water, you are also heating up the container holding the water. If you guys collectively ignore that issue so be it.
Nor have I seen anyone discuss their methods for thermally isolating their experiment from the outside world, whether that be isolating the bottom of your container from a table top or whatever. How can you possibly do thermal tests without even discussing this important issue on your thread?
Also, trying to make an estimate of your margin of error is critical in any experiment. i.e., "I calculate my COP as 1.7 +/- 20%," or whatever, but I know that's a tall request because you almost never ever see that on the forums for any experiments, period.
In my way of thinking, "part of the fun" is to tackle these issues and do better experiments.
Anyway, three replications from three different experimenters with multiple runs per replication, photographs, documenting of the procedures followed, control runs with a standard water heater, where each experimental run's data is crunched down to a COP value would be a reasonable requirement for this proposition. To be a pain, I will state again, produce reports comarable to a Grade 12 chemistry lab experiment. I don't think that's asking for too much.
By the way, what happened to the standard little resistive "coffee cup" water heater that you said you purchased? I saw some pictures of a 110 VAC light bulb immersed in a big jar filled with water. What's up with that?
Sorry for the "scolding" but it never hurts for you guys to push yourselves to do better and get better results. If nobody asks Daeomonbart for the stuff I listed above then I don't know what to say. All that I can hope for is that you do real experiments and get past saying that your data is preliminary, it's time for all of you to start doing definitive experiments and stand by your data. If you don't get to that point, the thread will just meander and go nowhere, and sink lower and lower until it is off the front page for good and dies.
MileHigh
« Last Edit: 2011-12-04, 21:41:26 by MileHigh »
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