Today’s high cost of energy as well as the increasing level of environmental awareness and political measures, spiral the search for modern and more efficient solutions in the field of energy saving. The environmentally friendly EC+ concept developed in close cooperation between Danfoss and NOVENCO is the latest market response to growing demands for energy saving. This most efficient system solutions for AHUs are miles ahead of the competition with unmatched overall system efficiencies of 85%. The EC+ concept, that is specifically conceived to increase the efficiencies of HVAC systems, comprises the NOVENCO ZerAx® series of high efficiency axial fans, high efficiency IE4 and IE5 permanent magnet (PM) motors and the intelligent and high efficiency Danfoss VLT® frequency drives.
EC+ system efficiency and compact AHU system design
With motor and frequency drive efficiencies both reaching above 95%, the ZerAx fan efficiency of 92% brings the overall system efficiency to an impressing 85%. This is 20-25 percentage points better than the closest alternative solutions, such as direct-driven centrifugal plug fans with EC motors. It is the highest possible overall system efficiency for AHUs available on the market. Because of the high efficiencies of the ZerAx, it is possible to design AHUs up to 30% shorter and 30% lighter and still have the same performance characteristics and hence cut expenditures. The ZerAx fans for AHUs are complete plug-and-play solutions to ensure easy and fast installation. The fan sound levels are significantly lower than those from other fan manufacturers. The fan lifetimes are 20+ years, which contribute to sustainability and guarantee low maintenance costs.
Dynamic pressure is the keyword
HVAC systems which only utilise the static pressure cannot achieve efficiencies above 90%, as the dynamic pressure goes to waste. To maximise the energy efficiency of any ventilation system, fans must use both static and dynamic pressures. The result is higher efficiency, lower energy consumption, reduced operating costs and lower carbon emissions.
The efficiencies of plug and centrifugal fans, as used in many HVAC systems, are calculated solely on the basis of the static pressure. This is because these fans are unable to utilise the dynamic pressure, which literally disappears into thin air. Axial fans on the other hand utilise both the static and the dynamic pressures, which allows for calculations based on the total pressure. Efficiencies above 90% are then achievable, as less energy goes to waste.
Although plug and centrifugal fans appear simpler and are more flexible constructions than axial fans, they turn quickly out to be expensive choices – both in terms of operating costs and the environmental impact. High efficiency axial fans consume much less energy, reduce cost and carbon emissions, which makes efficiency a critical key parameter in the choice of fan solution.
Difference in airflow between a centrifugal fan (top) and the NOVENCO ZerAx axial fan
ZerAx and ground-breaking fan efficiencies
Many centrifugal fans reach efficiencies between 65-70%, while axial fans usually perform at up to 80%. A main reason for the significant difference is in the way the air moves through the fan. In axial fans the airflows are parallel to the fan axis, whereas in centrifugal fans they flow perpendicular to the fan axis and thereby lose most of the velocity energy.
The minimum loss in axial fans is due to the aerodynamic design that gives straight airflows with no or very little turbulence. This difference in design generally provides higher efficiency levels in axial fans.
The NOVENCO ZerAx axial fans have unmatched fan efficiencies of up to 92%. These efficiencies push fan designs to new levels, and thus lower the overall power consumption and sound. ZerAx axial fans are the most energy-efficient on the market today.