Computerised methods for balancing ventilation systems.

Adequate ventilation with the "right amount of air, to the right place and at the right time" are important factors for achieving a good indoor climate. Thus it is of prime importance that the ventilation system is working properly. Using traditional methods, it is a very time consuming, and some times even impossible, task to balance ventilation systems to achieve correct air distribution. In most countries the growing concern about Indoor Air Quality has resulted in Building Codes demanding increased ventilation rates. This makes it even more critical that ventilation systems are correctly balanced. Otherwise the effort of solving one problem: "inadequate ventilation", may create two new problems: "draught and noise". This paper describes the "DPM method" which is a new method for balancing ventilation systems. The balancing "starts at the designer's desk" by doing a comprehensive computerised pressure loss analysis. The results from this analysis are then input to a PC connected with an electronic instrument. The PC/instrument may be used for balancing when the air terminals are already installed in the building. However, there is a much larger potential for time and cost savings when using the DPM method for pre-setting air terminals at the factory. For this purpose a "DPM machine" has been designed for computerised pre-setting and bar code labelling of air terminals. With impressive results the ventilation systems in a number of buildings have been balanced in the last two years using the described innovative technology.