Jed, Do you have information about where the ambient temperature was during this long time period? I and my simulation would expect the temperature to remain constant after enough time has elapsed when the only heating source is the pump and the ambient remains constant. If we know the temperature of the ambient as well as the temperature of the water, then we will know the product of the thermal resistance and the pump power. Only a time constant measurement can yield the value of each of these provided we know the thermal capacity of the test system. That is assumed to be 41000 joules per degree C per your report.
I have an extremely accurate measurement of the thermal resistance from the data you supplied which is .67 degrees C per Watt. My simulation was so accurate that it displayed an error of less than .02 degrees C. over an extended time period. The data I used was for the October 22 set where I followed the temperature transient from the peak reading for many hours afterwards. The actual time points were from 21610 up to 43217 seconds on that set. This period was right at 6 hours long and the temperatures were changing smoothly the entire time. So, if you have that constant ambient value, we can run a second check. It seems a little strange that the coolant was at that low of a temperature---17.64 degrees with the lab heating on. Most of the data you published shows the ambient at nearly 22 degrees C during normal working hours with the heat on. I bet the data was obtained during a long period without heating. Check that out and see if there is an explanation for the low temperatures. Dave -----Original Message----- From: Jed Rothwell <[email protected]> To: vortex-l <[email protected]> Sent: Fri, Jan 30, 2015 2:33 pm Subject: Re: [Vo]:Alternate Calculation and Calibration Method for Mizuno Report And . . . Here is definitive proof of what I say. It happens that Mizuno sent me a large data set which includes about 35 hours where nothing was happening. He left the computer running, and he left the heating on so the ambient temperature was reasonably stable. I see it was especially stable during the last 28 hours. The pump was also running all this time. Here are the cooling water temperatures for the first 14 hours and the second 14 hours: First 14: Average 17.85°C, min 17.64°C, max 18.08°C Last 14: Average 17.81°C, min 17.65°C, max 18.10°C There is no difference. The pump did not change the temperature. Using the adiabatic method of calorimetry we see zero heat in this data set. There is NO INCREASE in the water temperature even though the pump is adding heat the whole time. It has reached the terminal temperature for the pump input. Really, people should stop debating this. The pump cannot possibly affect this method of calorimetry. - Jed
