That would be a very simple means of providing excellent high temperature control.
A coil of tube inside the reactor containing water with a pressurised cold reservoir attached to one end to keep it filled with water and a pressure relief valve at the other end to release steam above a certain pressure. The pressure release setting could control the temperature very accurately, at any point from 100°C to 6-700°C, and the steam from the pressure relief valve could be sparged into a water tank for simple calorimetry. The water filled tube would absorb relatively little energy until the rector temperature rose above it's set point, at which point it would absorb a huge amount of energy with small temperature increase. Would give safe reliable hot-cat operation without danger of thermal run-away. On 9 October 2013 16:18, <[email protected]> wrote: > On 9/10/2013 12:20 PM, David Roberson wrote: > > I finally got around to checking my ECAT model performance with active > cooling control and the results were very interesting. First, I applied > normal heating to the device which leads to thermal run away conditions if > allowed to go beyond a certain critical core temperature. As expected, > the model showed that the ECAT began a path toward melt down. > > The path to destruction would proceed even when the original drive is > removed since the critical temperature was exceeded. Then, I allowed the > model to continue heating for a period of time and applied the brakes > quickly with a new load that withdraws a significant amount of extra heat > power from the system. This might be possible in real life if for instance > a phase change coolant were sprayed onto the core directly. The extra > cooling must be applied continuously while the temperature drops and > until an optimum trip temperature is reached. The turn around point must > be above the normal critical temperature since no additional heating is > required to achieve a condition where thermal run away can begin anew. > > The model demonstrated that this type of cycle could be repeated > indefinitely while the total power being generated by the device is > significantly above that safely obtained by heating control alone. I would > assume that a cooling method similar to that suggested above would take > less input power than the standard heating process that I have modeled > earlier so this type of control would result in a higher COP for the system. > > The model also demonstrated that a continual application of the extra > cooling resulted in the cores return to room temperature as desired. > Actually, the powerful cooling was not required to be applied once the > critical run away point was passed. In this case, the core would be > subjected to positive feedback that forces it toward turn off by itself. > > It is evident that a hybrid type of control system that uses both power > resistive heating as well as active cooling would perform the function. If > both techniques were available it might be possible to keep the ECAT > temperature very near the critical point in which case the COP would be > extremely high. For this type of tight control to work the loading as well > as all the other parameters which cause the critical temperature to vary > must be kept under tight control. This might be possible. > > > Good to see someone thinking! In fact I think the problem is really > simple. (And there should be no "extremely high" for overunity devices - > if they are not beyond infinity then you haven't got an engineer worth his > salt working on it). There should be no need even for an active system. > You simply need a passive system that presents a steeper load onset with > temperature (cooling effect) than the (expected) exponential power increase > with temperature produced by the reaction. > > With a few moments thought you can come up with a really simple one:- Put > the reactor into a stainless thermos flask, cover it with water, and heat > it up with its internal heater until the overpressure release of the flask > starts to leak steam. Disconnect the power and it should self-regulate and > hiss away for hours or days and there is your demo (until it runs out of > coolant). If you want a continuous system, then you might need to put it > on an electronic scale and organise a little pump to inject more coolant > very slowly to just keep the weight constant. > > Consider a Thermos flask that is capable of keeping tea hot for maybe 6 > hours. If we have a 2 liter flask and the temperature drops from 100 down > to 70 degrees in 6 hours, then that represents an total heat loss of > 4.2kJ/kg/K * 2kg * 30K => 250kJ or an average heat loss rate of > 2.5*10^5J/(6h*3600s/h) => 12watts. If we do the calculation a little bit > better and assume that it is an exponential decay which is heading for 20C > after infinite time then we get a time constant of 12.8h, and the rate of > heat loss at the start is simply the total heat divided by the time > constant (4.2*10^3*2*(100-20)/(12.8*3600)) => 14.6watts. So this means > that if we supply 15 watts of power by some means, then whatever is in the > flask will eventually reach boiling point and stay there. > > So if the reaction can produce more than 15 watts of power while it is > held at 100C, then it must remain at this temperature because as soon as it > rises above 100C, the water will boil and steam will exit the flask > providing an almost infinite heat sink capability (boiling water can easily > consume kilowatts of power without allowing the temperature to rise > significantly). If 100C is not hot enough then we can either pressurise it > (with a simple overpressure valve), or go to a lot more trouble and use a > higher boiling point fluid. The sort of silicone oil that they use in > diffusion pumps comes to mind. You would need to have a closed system (at > least not allow oxygen to get to it I think) but you could easily get > boiling points around 300C which could be further raised by pressure. > Mercury would be an excellent boiling point coolant for 360C and up. (It > used to be used and worked very well in diff pumps before people got all > paranoid about it). > > Rossi's "December Test" suggested a power generation capability of ~2kw > while being held at a peak core temperature of approx 500C. The "March > Test" suggested a power generation capability of 530w while being cycled > around a temperature of approx 320C at the core. Provided the core reactor > in the two cases is very similar, we can use these two points to solve > Arrhenius' equation for the temperature dependence of the reaction rate. > We get a pre-exponential factor of 1.6*10^5 and exponential (activation > energy / R) factor of 3380. Arrhenius' equation thus suggests a power > generation rate dependent on temperature given by Power = > 1.6*10^5Exp-(3380/Temp in K). Using this equation to see what happens at > 100C tells us that it should generate a power output of 18.6 watts. > > So Rossi's reactor should in fact work and generate steam continuously if > simply put in a thermos flask and warmed up to 100C! If we were to > pressurise a well insulated container to a reasonably easy to obtain > pressure of say 10 atmospheres (giving a water boiling temperature of 180C) > we would expect to be able to generate 92 watts in a continuous manner. If > we were to set up a mercury cooling loop, then we could run it continuously > at kilowatt levels with no active control and just a small pump to inject > the condensed mercury back into the pressure chamber. >
