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.
