During the 1940s and 50s, the “BEEB” (as the British Broadcasting Corporation is affectionately known in Britain), broadcast a radio show known as “The Brains Trust.” During each of the 84 broadcasts that were made, a panel of four erudite personalities attempted to answer questions that were put to them. Tree of them anchored the program and the fourth place was occupied by some well-known intellectual. Some of them regularly occupied this space. One of the three respondents who anchored the program began his response to any question by stating that “it all depends on what you mean by……..” a particular word or phrase. He was C. E. M. Joad, a philosopher and psychologist who had written an excellent introduction to philosophy. His phrase became part of everyday language usage in the British Isles: even teenagers would be heard using it. With a laugh of course!

To simplify all the operations needed for calculating the variables which play a role in the evaporative tower cooling process, some electronic sheets concerning the zero-dimensional model have been developed. The first sheet named “property” lists the thermophysical properties which are mainly used in the following calculations involving dry air, saturated vapor and liquid water. The relevant proprieties are: density, specific heat, dynamic viscosity, thermal conductivity, Prandtl number, specific humidity and latent heat. The peculiarity of such sheet lies on the fact that all these parameters are exclusively calculated according to temperature under standard atmospheric conditions. In this way it is convenient to act under a mathematical point of view, as the equations are single variable and the variation of the parameters can be easily represented in a diagram. Another strong point is the opportunity to directly compare the properties of dry air, of vapor and of water at the same temperature: hence it is possible to easily obtain all the values that characterize each specific context.