CleanTech Cooling Enabling power plants to conserve and protect scarce water resources

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CleanTech CoolingEnabling power plants to
conserve and protect scarce water resources
Inventors Team from the National Renewable
Energy Laboratory
Team Members Rick Atkin Emilie Dressaire Maria
Persson Gulda Janette Heung
Stuart Wall Michael Wick
Fall 2008
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Overall Value Chain Where it all fits together

• Combined technologies improves power plant
  efficiency by 0.4 640K annual benefit for new
  solar thermal or coal fired power plants
• Reduces water consumption and environmental
  footprint
• Allows for greater flexibility in power plant
  location

Heat Exchanger Fan
Solar Thermal Power
Air Cooled Condensers
Heat Exchanger Tabbed Fin
Traditional Power (Coal)
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Benefits of Air Cooled Condensers (vs. water
cooled)

• Flexibility in power plant location
• Reduces water consumption, essential for areas
  such as desert
• Better for environment
• Limits temperature increases in rivers and creaks
  traditionally used to cool
• Shorter lead time for power plant permits

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Cooling Technologies Two unique technologies

• Tabbed fins - Patent App 0169019
• Critical improvement
• Adding small fins to the surface plates in heat
  exchangers
• Robust design
• The innovation tackles two inefficiencies of
  standard fins
• - the irregular air flow patterns around the
  pipes
• - the reduced air speed along the fins (in thick
  boundary layers)
• Significant improvement
• The heat transfer is increased by up to 12

Water / Steam
air

• Fan airfoils Patent Issued - 6,899,524
• Critical improvement
• 3-10 meter blades for large fans (4-12 blades)
  used in cooling towers
• Differences from prior art different
  thicknesses at root
• and tip leading to 2-3 efficiency gain
• Unique design
• Design performances are independent of
  roughness Therefore, 4-5 efficiency gain
  expected if roughness is an issue

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ACC is a fast growing market NREL technologies
could create 500M annual benefit by 2012

Value per Year of 5 efficiency gain 504M
Air Cooled Condenser Market
More efficient ACC cooling uses less energy so
the power plant can sell more of the energy to
the grid
504M/year
1,557
1,600M
Solar ACC
Solar-Thermal 43
1,210
1,200M
56
800M
Non-Solar ACC
1,299
Non-Solar 12
1,154
470
10
400M
460
0M
2012E
2008F
2003
2012E
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Team Recommendations
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Startup Options Why not pull IP out of NREL
and form Start Up?
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Appendix
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Appendix Interviews Conducted

• Industry Consultant
• Jeff Atkin - Senior Counsel at Foley Lardner
  LLP
• Terry Peterson PhD , Solar Power Consulting ,
  (Member of Natural Resources Council)
• John Maulbetsch, EPRI Consultant
• Ken Hennon, Clean Air Engineering
• David Wheeler, Clean Air Engineering

• Air Cooled Condenser Manufacturers
• William Wurtz, SPX
• Dave Sanderlein, Holtec
• Solar Thermal Developer
• David Kluttz, Acciona
• Fan Blade Manufacturer
• Confidential
• Paul Nelissen, Howden Buffalo
• Academic
• Harvard Machine Shop Louis R Defeo
• Inventors
• James Tangler, NREL
• Chuck Kutscher, NREL

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Appendix Solar Thermal Value Chain
Air Cooled Condensers
Solar Thermal Power Plant
Steam Turbines
NREL Technologies
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WATER - Air Cooled Condensers conserve water,
protect environment, and enable power projects
where water supply is very limited
Water Shortages In the United States Shown in Red
Thermoelectric Power Gen 136 M Gallon/day of
Freshwater!
Example ACC used in Mystic, Boston to minimize
impact on environment. An ACC system does not
release hot water back into the river/ bay
Source http//ga.water.usgs.gov/edu/wupt.html
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Appendix - Cooling Technologies Summary of
Challenges
Patent protection
Feasibility
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Appendix - Technology Virtual Tour of Power
Plant
Link to Virtual Tour of an Air Cooled Condenser
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Appendix - IP Review Tabbed Fin History of
Patent Application

• Officer Bonk Officer Duong

Oct. 07 USPTO emits non final
rejection. Prior art makes most of the claims
unpatentable. 1- Drawings fail to illustrate all
claims 2- Specification are not clearly
stated 3-Claims rejected idea of tabs and
roughness to induce turbulence and collars around
the tubes to increase heat exchanged already
patented (US 5,697,432 US5.682,784). tabbed
fins for heat exchangers already patented (US
5,875,839)
Oct. 08 USPTO emits non final rejection Not
convinced by last arguments. Brings up same prior
art as before
Jul. 07 USPTO requires restrictions. Not a
single general invention 1- Fin fabrication 2-
Fin design 3-Fin and heat exchanger
June 08 USPTO emits advisory action The porosity
range raises new issues
April 08 USPTO emits final
rejection. Prior art makes most of the claims
unpatentable.
Jul. 05 NREL files patent
Aug. 07 NREL responds to restriction
requirement. Focus emphasized on design of tabbed
fins and their use in heat exchanger 1- Claims
1-17, 38-49 canceled 2- Clains 50-67 added to
describe position, angle, height and shape of
tabs more precisely
Jan. 08 NREL responds Change title,
modifies claims and agrues for non-obviousness. 1-
Tabbed heat transfer fins and air-cooled heat
exchanger with tabbed fins 2- No modification of
drawings, Claims modified to insist on tabs angle
and presence/role of holes Non-obvious
difference between tabs and slits angle of
tabs, location of tabs on both sides of fins and
roles of holes
May. 08 NREL responds Amendement after
final rejection. reduction of tabs angle
surface area of the holes specified (porosity)
July. 08 NREL responds Very similar
document to the one of May 08 50 of tabs on
surface 1 and 50 of tabs on surface 2
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Appendix - IP Review Tabbed Fin Prior Art
Review
(1)

• Prior art
• Risks of infringement

(2)
This prior art is quite threatening as it shows
tabs fairly aligned along the streamlines. It
only fails to show their role to limit eddies
formation and their presence on both sides of the
fin.
US 5,697,432
This prior art is not so threatening since the
patent shows the importance of the alignment
between the flow and the tabs, not possible here.
(3)
This prior art is much less significant than the
previous one because the designs are so different.
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Appendix IP Review Tabbed Fin Freedom to
operate

• Necessity of complementary assets
• Large scale manufacturing facilities
• Proprietary Tube Fins
• Cooling system design (how to arrange fins,
  pipes)
• Main players protect their design with patents
• Design of parts of the heat-exchanger
• Design of the heat-exchanger as a whole
• Complementary assets and protected state of the
  art systems make it difficult to compare
  efficiencies, prototypes and to build a full
  air-cooled condenser independently

GEA
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Appendix IP Review Fan Airfoil Prior Art
Used Today versus New Invention
Prior Art NACA 632-515
New Invention
Root
Root

• Chord thickness 14
• Lower drag 0.007
• Lift Coefficient 1.5

• Chord thickness 15
• Lower drag 0.009
• Lift Coefficient 1.256

Tip
Tip

• Chord thickness 15
• Lower drag 0.010
• Lift Coefficient 1.256

• Chord thickness 10
• Lower drag 0.008
• Lift Coefficient 1.5

New unique airfoil design lowers drag and
increases lift coefficient which improves
efficiency
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Appendix - IP Review Fan Airfoil Specific
Prior Art

• Prior art
• Risks of infringement

(1)
(2)
(3)
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Appendix IP Review Fan Airfoil Freedom to
Operate

• Patent is already licensed to a company in the
  fan industry
• Neither a start up nor a exclusive license
  option is possible with the fan.

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Appendix IP Summary
Patent protection
Feasibility