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. Dave
