I myself took Layman at face value, for quite a while, and tried to help - until it became bloody obvious he was just fooling around and wasn't listening. If you bother to read the thread, you will see that. Your example is useless. First, his point was to do with a ceiling fan circulating air in a closed room. Your example, obviously, is of a fan blowing cooler air from outside through a machine and back out again - a totally different situation. Secondly, as usual you made no effort to explain the point you were trying to get across with this example. The reader was left to guess at what the hell your contribution is designed to achieve. I have yet to see a single contribution from you with enough explanation or commentary to make clear in what way it is relevant to the subject at issue. You may be brilliant for all I know, but your ability to communicate seems to be hopelessly inadequate. You appear to be either lazy or else not really at all interested in the science. That is why I have no time for your contributions. I wish it were otherwise, as I am delighted to talk science with anybody.