8 Saint Marys St. Boston, MA 02215 USA [email protected]
www.nbdnano.com
NBD Coatings Enhance Heat Transfer in Pure Steam Condensers Up
To 200%!
NBD Nanotechnologies, Inc. (NBD) is inspired by
the Namibian Desert Beetle, which harvests its own
drinking water from moisture in fog.
With biomimetic micro- and nano-scale coating
technologies, NBD develops functional surface
coatings that sustain the more-efficient dropwise
condensation to improve the performance of
condensers in industrial applications, such as
power plants, desalination plants and heat
exchangers.
Dropwise condensation provides significant heat
transfer enhancement compared to filmwise
condensation (the default condensation mode for
non-surface treated condensing surfaces).
NBD technology promotes dropwise
condensation and enhances pure steam external
condensation heat transfer coefficients by 2-3
times compared to filmwise condensation on the
non-surface treated tube.
Preliminary laboratory results have shown the
coatings superior durability under pure steam
conditions of 500 hours with nominal performance
loss.
NBDs technology uses scalable coating techniques
that can be easily integrated into heat exchanger
manufacturing processes. NBD is committed to
NBD Nanotechnologies, Inc. Advanced Surface Coatings for
Enhanced Condensation
Demonstrated enhancement of condensation
heat transfer coefficients in pure steam of up to 200% when
compared to filmwise condensation.
Simple, scalable fabrication process (dip coating and/or
spraying)
Current run time: 500+ hours
Optimized for Copper and Copper alloys
NBDs surface coating sustains dropwise condensation (left) with
beaded droplets that has 2-3 times greater heat transfer
coefficient than conventional filmwise condensation as shown
(right) .
Key Attributes
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8 Saint Marys St. Boston, MA 02215 USA [email protected]
www.nbdnano.com
ensure that our coatings are environmentally
benign and durable under a variety of operating
conditions.
NBD combines a multidisciplinary team with
expertise in surface chemistry and condensation
heat transfer, as well as collaborations with world-
class researchers at the Massachusetts Institute of
Technology, the University of Illinois at Chicago,
and the University of Nevada, Las Vegas.
NBD is well-positioned to develop leapfrogging
technologies for addressing energy-efficiency
innovations in condensation applications.
NBD Coatings for Dropwise Condensation
Tackling the Bottlenecks of Surface Coatings
NBDs coating durability and performance is due
to our innovative and proprietary techniques that
ensure adhesion onto the substrate while not
compromising the thermal resistance due to the
coatings sub-microscale thickness.
Traditional superhydrophobic surfaces, which
exhibit sessile drop water contact angles exceeding
150, have been commercially demonstrated.
However, superhydrophobicity does not typically
guarantee dropwise condensation. Competitive
superhydrophobic surfaces are typically attained
by micro- and nano- structured surfaces with low
surface energy coatings such as self-assembled
monolayers (SAMs). These coatings are not very
durable and often degrade over time. Additionally,
micro/nano-texturing causes condensate pinning
onto the surface which results in filmwise
condensation, thus reducing the heat transfer rate.
NBDs superior technology has been proven on
copper substrates. NBD is also exploring
alternative substrates, such as copper alloys and
stainless steel.
NBD is currently seeking commercial opportunities
to demonstrate its advanced materials technology.
Case Study: Condenser Efficiency in Steam Turbine Power
Plant
Theoretical calculations for improving the heat transfer
coefficient by 3 times with NBDs condenser pipe coating, suggest
12% increase in the condensers thermal efficiency. These heat
exchanger calculations, based on the effectiveness-number of
transfer units (-NTU) method, compute the condensers efficiency
improvements using the operating conditions* of an existing steam
turbine power plant (Newington Station Power Plant). Note
*The -NTU calculations use the following values: effectiveness
of 0.6, condenser steam pressure of 0.982 Psia, cooling water
temperature of 66F and condenser tube dimensions (650 tubes, 30ft
long, 9/8 OD). The NTU is a dimensionless parameter that indicates
the number of units needed for transferring the desired heat input.
NTU is proportional to the heat transfer coefficient.
Newington Station Power Plant in Newington, NH
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