The new High Efficiency
Fan (HEF) family of low-noise axial fans are said to feature
outstanding aerodynamic and acoustic characteristics. Development
and design of the new fans are the result of a joint project
involving Hidria’s R&D department, Rotomatika Fans
(a Hidria company), and the University of Ljubljana.
issue: June 2003 APPLIANCE Magazine
High-Efficiency HVAC/R Fans
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Slovenian corporation Hidria has launched a new line of high-efficiency axial fans for the HVAC/R industry.
According to Vojko
Sedej, director for Rotomatika Fans, the HEF fans, which are
made of five aluminium-sheet blades, solve the problem of
non-stable fan characteristics, which has been a weak point
in classic blade design. Solutions with four blades are also
The main advantage
of the patented fans is the construction and special shape
of the blades. According to Mr. Sedej, the innovative blade
design gives superior results for minimum as well as maximum
airflow. “The fan blade is designed with a similar profile
cord as is used in a laminar air profile,” he explains.
The blades are
said to have a stable air lift with almost no separation of
the air stream in the working region (50-85 percent of maximum
flow) of the fan. “The airflow around the blades in
the optimal efficiency region is very stable with minimum
air separation near the hub,” says Mr. Sedej. “Instability
in the pumping region can limit the use of axial fans in a
low-flow region (normally under 50 percent of maximum flow).
Our fan can be used with some efficiency loss until 30 percent
of maximum flow.”
In addition to
efficiency gains, the advanced aerodynamic characteristics
keep the fans’ noise level low under all conditions,
Mr. Sedej says. “Lower noise is result of the small
amount of air separation around the blades, the high-quality
design of the intake confusor, and a properly-designed gap
between the intake confusor and blades,” he explains.
The compact shape
of the HEF blades is also said to allow for several air-conditioning,
ventilation, heating, and refrigeration (HVAC/R) applications.
The fans are built with single- or three-phase a.c. electric
motors with external rotor and variable speed drives, according
to customer requirements. According to Mr. Sedej, the fans’
blades are constructed out aluminum because the material can
be easily formed and, at the end of the life cycle, easily
of the axial fans are standard diameters of 450-650 mm, while
the expansion to bigger and smaller diameters will be available
by the end of the year. The company is also developing an
electronically commutated d.c. motor to complete the offering
that will also be released by the end of 2003.
to Hidria, optimization of its HEF axial fans and their
high air-stream stability under both sucking and pushing
working conditions were supported by CFX simulations,
as depicted here.
for a larger image.)