Recently I have been exploring issues associated with thermodynamics since it has been many years since I studied the subject. I wanted to understand why certain rules apply and exactly what that suggests is happening at the basic levels. This particular subject comes up often as we analyze LENR devices and so it is useful to pursue.
I was considering the Carnot cycle and other heat engines when it became apparent to me that this is nothing more than a statement that the COE (conservation of energy) applies to these devices and that there is nothing mysterious happening. The fact that a heat source and sink is required for the engine to operate is easy to understand in the context of COE. The way I approached the topic was to consider an ideal gas that exists in a given state. The average kinetic energy of the gas atoms is directly proportional to the absolute temperature (K). If you double the temperature then you double the kinetic energy of the particles. If you halve the temperature, then you will find that the kinetic energy is reduced to one half of the original value. So, if I take a given volume of this ideal gas at any given temperature and extract mechanical energy from it then only a portion of the original energy remains. For this thought experiment I do not allow any other paths for energy to escape. In a simple example lets extract 1/2 of the kinetic energy from the experimental gas source. This would not be a bad engine if it could convert one half of the available energy into mechanical energy. The exhaust gas would thus have exactly 1/2 of the original energy it had before it was put to work so its temperature must be 1/2 the original value. The Carnot efficiency is defined as 1-Tc/Th. In the example that I reviewed the efficiency is 1-.5 or .5 which is 50%. This makes a great deal of sense since my machine extracted exactly one half of the energy that it could have taken if it operated on a perfect cycle exhausting 0 degree gas. Someone with a different engine than mine would obtain better results if the exhaust gas is ejected at lower temperatures and hence less kinetic energy. It is important to notice that no energy is lost in this operation. The remaining energy is resident in the form of kinetic energy of the ideal gas molecules and might be extracted at some later time by another process. I hope that this post is useful to others and will help to burrow through the complexity of thermodynamics in a way that makes the behavior understandable to everyone. It will be interesting to consider the emission of radiant energy using similar thought processes. Answers for some of the difficult questions that have been recently discussed might materialize as a consequence. Dave
