Some model concepts: First, if we assume that there is a functional relationship between the power output of a mass of Rossi's material and the temperature to which it is subjected there will be a slope to that curve around the operating temperature. A test fixture might be constructed that allows us to heat the material to a desired temperature and then measure the total power output with a calorimeter. The ideal fixture would have a very low value of thermal resistance to ambient so that the material being tested would not become unstable and overheat.
We would construct the desired curve by taking the difference between the total output power and the drive, which we usually refer to as excess power. If lucky, the curve can be constructed over a large range of temperature, especially covering the region of operation for the ECAT. My model allows me to choose any functional relationship that is measured. I have conducted test runs on linear, second, third, forth, and exponential functions. All seem to behave in a similar manner, but it is evident that the higher order curves make things more critical to adjust, but not impossible. It would be grand if the actual curve associated with Rossi's combination of mix and gas were measured. Once a curve has been chosen, there are important parameters that define the behavior of the system. The first derivative of the curve defines a form of gain that ties a differential change in temperature to a differential change in output power. This can be translated to mean that a 1 degree change in temperature causes a 10 (example) watt change in output power at some temperature. If the thermal resistance of the ECAT is set to .1 degree K per watt then a product of the two yields 1. This is the critical temperature where the device becomes unstable. A noise level increase in device temperature results in a larger drive which proceeds toward some upper power point where the device either self destructs or limits. The process is slowed down by the necessity to heat the device materials as the temperature increases. This is where my model has a thermal capacity as a parameter. The real world devices also take time to heat up which allows the control waveform to function. This model behavior thus has several characteristics that mimic real life. First, a certain minimum amount of heat must be delivered to the active core in order to allow the combined system to reach the critical temperature. Operation below the critical temperature results in very low COP, which is not desired. The demonstration of Celani's device was an example of operation within this region. So we choose a drive power that allows the device to reach critical temperature and a bit extra for control. The drive is applied and the temperature rises and the critical point is reached where the positive feedback takes over. At this time, the temperature begins an exponential rise toward infinity. The heat output increases rapidly due to the high order dependency. The output power ramps ups and we decide that it is time to reverse the direction of the temperature curve. A carefully timed drive power drop to zero is orchestrated and the output power begins to fall downward toward zero. The stop timing is critical if we are to have a high COP. A super carefully timed edge can result in a long delay period where the output power is just barely heading downward. This of course will result in a large COP, but the stability would be difficult to maintain. I prefer to have margin in my model runs and accept a reasonable COP, where 6 is fairly typical as in Rossi's statements. The power output is heading downward after the reversal and that is again reversed by the reapplication of the drive waveform. The process repeats from this point forward. Operation of the device is restricted to be within the unstable positive feedback region if one is interested in a reasonable COP. I tend to keep the output power near the upper point of no return so that the COP is maintained less than 10, but more than 6. I wanted to mention one observation that is fairly important. If you set the upper turn around timing extremely critically, it is possible to get a very large COP. The reason is that the time constants associated with the thermal resistance and capacitance become quite large. The timing is as critical as it is large however and the system is balanced upon a sharp edge. It typically does not take long for the positive feedback to dominate and the curve begins a rapid decent. I hope this helps to explain the model I am using for my simulations. Dave
