Mads Mysen, Axel Cablé, Peter G. Schild, Kari Thunshelle
Bibliographic info:
35th AIVC Conference " Ventilation and airtightness in transforming the building stock to high performance", Poznań, Poland, 24-25 September 2014

Demand controlled ventilation (DCV) considerably reduce the ventilation airflow rates and energy use compared to Constant Air Volume (CAV) systems. DCV in commercial buildings is probably a prerequisite to achieve ambitious energy-goal. However, evaluation of real energy use demonstrates that the energy saving potential is seldom met. DCV-based ventilation systems must become more reliable to close the gap between theoretical and real energy-performance. These unfortunate experiences with DCV have many causes, including: inadequate specifications and hand-over documentation, balancing report not suitable for DCV, communication errors and lack of knowledge about DCV-systems among decision makers.

There is also a significant difference in performance between DCV-systems and simpler systems that, for example, vary the airflow rate with pre-set air damper positions, or that use a single sensor for several rooms. In order to verify that a DCV system fulfils the expectations in terms of indoor climate and energy use, one must specify measureable objectives of performance.

In this paper, the most important control points during commissioning of a DCV system are described. Measureable objectives of performance should be specified. In particular, recommendations are given in terms of:

  • control and measurement of Specific Fan Power
  • balancing procedures and control of airflow rates
  • requirements for sensors and dampers
  • hand-over documentation
  • deviations during commissioning and corrective procedures.