Abd ul-Rahman Lomax <[email protected]> wrote:
> Somehow the reported facts got lost in this massive thread, which I've not > been following. So I searched for "130 KW." I found the first message here > was Jed's, and that "power peaked briefly" at 130 kW. > > I am commonly irritated by people who discuss and confuse power and energy > in CF discussions. "Briefly" -- with 130 KW -- could be seconds. The power > would have been detected by a rise in coolant temperature. > I have heard it was about 18 minutes, but to be honest I don't recall where I heard that. Here is what NyTeknik reported: "Initially, the temperature of the inflowing water was seven degrees Celsius and for a while the outlet temperature was 40 degrees Celsius. A flow rate of about one liter per second, equates to a peak power of 130 kilowatts. The power output was later stabilized at 15 to 20 kilowatts." http://www.nyteknik.se/nyheter/energi_miljo/energi/article3108242.ece "A while" is probably not a few seconds. It would take a few minutes for the outlet temperature to stabilize at 40°C. By the way, when the temperature gets that high, you start to get some inaccuracy. A 5°C temperature difference and an operating range from 20°C to 30°C is ideal, according to McKubre. The 40°C does indicate ~130 kW but it is more of an approximation than the 15 to 20 kW. (By the way, that means they saw the power fluctuate between 15 and 20 kW.) Regarding this reactor, McKubre pointed out that the outlet thermocouple may be too close to the cell, which would cause an over-estimation. I think this is particularly true at higher power, when the metal housing may conduct some heat to the thermocouple. When the outlet water is 5°C above tap water that will not be a problem. I do not know know where the error bars would be, but based on conventional boiler inspection manuals, a 10% error would not be surprising. > Really, the heat transfer will be limited by the flow of the coolant, as > long as the heat generator is well-designed. > That is correct. As I pointed out elsewhere, the fact that the reactor is long and thin makes me think the cell is too, which means it resembles a fission fuel rod or a fire or water tube, with maximum surface area. It could have cooling fins as well, for all anyone knows. The limiting factor is, of course, how hot it gets inside. I believe the reaction works best at around 600°C and it conks out above that. - Jed
