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Associations
Supplied by ebm-papst compressor that failed , you could not replace it with the same model if it did not meet the standards . You would have to find a more efficient product instead . This increased the demand for more energy-efficient products , which in turn reduced energy consumption and carbon emissions in the long run . According to some estimates , the ErP Directive saved some ± 20 million tons of
CO 2 emissions since 2012 .
These figures are based on the EU market , but similar standards and regulations are also followed by other countries and regions , such as the US and ASHRAE . Therefore , the ErP Directive has a global influence on the eco-design of ALL energy-related products .
The ErP Directive is a mandatory requirement for the European market , and it influences the product selection and replacement decisions of the customers and suppliers . In South Africa , however , there is less incentive and awareness to choose more efficient products , even though they can save energy and money in the long run . The suppliers and contractors often prefer to sell cheaper and readily available products , rather than premium and compliant ones . This is a short-sighted approach that ignores the long-term implications of energy efficiency and environmental impact . Determining whether a fan conforms to the ErP regulation – this involves assessing the efficiency of the fan as a whole , i . e ., the entire unit comprising control electronics ( if fitted ), motor and fan impeller . It is based on the ratio of air flow to power consumption . The higher the overall efficiency , the more efficient the fan . The ErP Directive sets minimum Efficiency values for different types of fans . Refer to graph :
There are different kinds of fans , such as axial fans and centrifugal fans . Axial fans have a hub and blades that rotate around an axis . The air enters and exits in the axial direction . Centrifugal fans have blades that curve outwards from the hub . The air enters in the axial direction and exits at a 90-degree angle ( centrifugal forces ). Depending on the application , you need different fans for different purposes . Axial fans are usually used for low-pressure applications , such as in the HVAC & R industry .
Centrifugal fans are used for higher-pressure applications as also found in the HVAC industry , namely for Air Handling Units ( AHUs ). The power absorbed by a fan is measured by its pressure and volume flow rate .
Axial fans have a region where the pressure drops and then rises again . This is called the stall or saddle region , which is dependent on the fan geometry , blade angle and speed . In this condition , the fan is rotating but not delivering the full potential of air flow . The pressure is mainly determined by the velocity component , which is why we design the ducts with specific velocities .
If there is turbulence within the ( suction ) airflow path , this disrupts the pressure balance and causes noise . This is typically in the range of 250 to 500Hz . Higher frequencies are always easier to attenuate . A conventional axial fan without a rotating diffuser , has high velocity regions near the blades and a large recirculation zone behind the fan . This reduces efficiency and increases noise . A fan with a rotating diffuser has lower velocity regions and a smaller recirculation zone . An optimised design with a rotating diffuser has more uniform velocity distribution and minimal recirculation . This improves performance and reduces noise . Depending on the application , you may want the best possible Air-Throw within your typical application .
“ According to some estimates , the ErP Directive saved some
± 20 million tons of CO 2 emissions since 2012 .”
Supplied by ebm-papst
Another benefit of the rotating diffuser design is the increased rigidity thereby allowing the impeller to rotate at a higher rpm without deformation . This gives us more power density , which means we can use a smaller fan with higher RPM and get better performance and efficiency .
This is useful for applications where optimal air-flow designs are necessary . In the past , you could not use axial fans for these applications , but now we have a solution that can meet all your requirements .
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RACA Journal I January 2024 www . refrigerationandaircon . co . za