When the EPR hits the fan, or…the killing of the fan energy

The last decades big steps have been made on the road to develop and design energy neutral buildings. Despite the large list of developments and improvements of all kind of energy saving technologies we see specifically for the larger non-residential buildings that the electric energy use for fans hardly show any reduction and becomes a dominant factor in the total energy use of these buildings. The fan energy currently counts already for approximately 15-20% of the total building related energy and becomes increasingly important. Among other developments, the work of IEA Annex 35 “Hybrid ventilation in new and retrofitted office buildings” and IEA Annex 62 “Ventilative cooling” revealed new directions in the design of ventilation systems. However, in daily practice the HVAC designers and installers do not seriously pick up the (new) knowledge and keep on going the well-known traditional way: designing and realizing mechanical ventilation systems with a total pressure drop of over 800 Pa. The reason not to do so, does not only lie in financial arguments, but is based in a much broader range of barriers. Of course, the unfamiliarity and knowledge gap of how to design lowpressure systems is a relevant stumbling block, but also the “wish to control” the air flow, the IAQ and the comfort conditions results in installations that are fully equipped. All kind of provisions are foreseen that filter, heat, cool, humidify, recover the heat and control the air. And this ends up in the well-known high-pressure system, that needs to be equipped with big fans to provide the air in the right places. To come to a serious reduction in fan energy for ventilation, the above described circle has to be broken.