Very powerful simulation softwares are available today. They should allow rational choices from early design stages, among many different alternatives. When using such tools, the bottle neck is no more on computer side but in the modelling. Better and better compromises have always to be found...

On the basis of their thermodynamic properties and their historical development, some “Strength-Ideas” proposed which lead to the conclusion that, properly designed, heat pumps have a good future and will contribute to lessen the global CO2 emission burden.