dissipation

Ensuring an indoor environmental quality that is acceptable to the majority of users, while also being energy efficient is a challenge. In addition, both user demands and the climate change are making it even more difficult to ensure good indoor environmental quality. One of the solutions to combat climate change is free cooling systems, such as ventilative cooling. 

Application of the principle of the balance of mechanical energy gives a constraint on the possible values of the junction coefficients at a duct system junction. In some cases the recorded junction coefficients in the literature do not satisfy this constraint. The values given may then be questionable. The terminology in connection with junctions is discussed and the role of the principle of balance of mechanical energy in duct system flow modelling is considered in some detail.