Transcript Energy System Research and Testing (Conversion) Activities at NREL Gerry Nix

Energy System Research and
Testing (Conversion) Activities at
NREL
Gerry Nix
March 20, 2003
Goal: Reduce Cost of Geothermal
Electricity by at Least 1¢/kWh
• Make the Plant Less Costly – Reduce Investment
• Make the Plant Perform Better – Higher
Efficiency, Greater Output
• Make the Plant More Robust – Harder to Break
• Make the Plant Easier to Operate – Reduce Costs
via Automation and Instrumentation
• Make the Plant Easier to Maintain – Better
Materials and Designs
Time Frame is in the Next 5 to 7 years for Implementation
Cost Reduction Targets
• Binary Plants – Better Cycles (NREL,
INEEL)
• Enhanced Heat Transfer (NREL, INEEL)
• Better Materials (NREL, BNL, INEEL)
• Innovative Components (NREL, INEEL)
• Better Instruments (INEEL, BNL)
• Additional Revenues (BNL, LLNL)
Low-Temp Resources are
More Common
• 83% of the sites
require binary plants
(also, EGS/HDR will
35
Binary
Flash
30
25
20
%
systems
energy
15
10
5
0
110 130 150 170 190 210 230 250 270 290 310 330
Resource Temp C
Frequency of occurrence and energy of
hydrothermal convection systems identified by
the USGS in 1978
most likely need binary
plants)
• And 50% of the
available energy is
below temperatures
requiring binary plants
(170C)
Better Materials
Polymer corrosion
barrier coatings:
• Prevent corrosion of
geothermal plant
equipment
• Reduce maintenance
expenses
Steam vent at Cove
Fort after 5 years of use
Approach is to use inexpensive coatings with special
properties on inexpensive base materials, with
performance equivalent to exotic alloys
Extensive Field Testing
(Mammoth, Cove Fort, CalEnergy)
Large Life Cycle Cost Savings
$570,640
$648,029
$473,594
$116,679
PPS/CS
CS
Stainless
Titanium
Collaboration with Curran, Int.
• New Plant Built for
PPS Business
• Perfected Electrostatic
Application
• R&D 100, FLC
Awards
Future Work
• Perform Long-Term Testing of Operating
Equipment
• Evaluate at Temperatures to 350°C
• Expand Number of Test Sites and Partners
• Test New, Thin Coating for Finned Tubing
Exposed to Brine Spray
Why Improve Heat Rejection?
• 90% of geothermal heat is
rejected; condensers
make up 20-30% of plant cost
• Plant power will increase 1% for every
1ºF drop in condenser outlet temperature
• Output of air-cooled plant can drop more than 50%
in summer, when electricity is highly valued
• Water cooling can greatly reduce reservoir pressure (The
Geysers)
• Western states face water shortages – air cooling most likely
required for new plants, including EGS and HDR
Air-Cooled Condenser Research
Transpired and Tabbed Fins

Innovative designs

Increase performance by 30%

CRADA with manufacturer (SRC)
Bottom line: Improved heat transfer reduces heat exchange area,
and can reduce cost of electricity by 0.5 cents/kWh
Heat Transfer (Btu/h)
Advanced Fins
ITS Test Results
30,000
25,000
20,000
15,000
Pleated transpired fin
10,000
5,000
Plate fin
0
0
10
20
Fan power (ft-lb/s)
30
Helical fins
Poly. (Plate fin)
Poly. (Pleated
transpired
fin)
heat
transfer
Poly.
(Helical fins)at
Latest tab fin shows about 40% more
the
Same fan power with only 11% reduction in air flow, plan is
To fabricate prototype and test at ITS
Fin-on-Plate Air-Cooled Condenser
Test Setup
Heat Tarsnfer Coefficient vs. Pressure Drop
Fin-on-Plate
Condenser, 36%
higher heat transfer
coefficient for the
same pressure drop
Heat Transfer Coeff., Btu/ft2 h F
16
14
12
10
8
6
4
fin-on-plate data
tube and fin (4 rows)
2
0
0
0.2
0.4
0.6
0.8
1
Pressure Drop, in H2O
•Potential Industry Partners for Manufacturing; Linde, GEA
Rainey, API Heat Transfer
•Carry out field testing in collaboration with Exergy
•Work with Experts in HX area (Prof. Ken Bell)
•Collaboration with HTRI
Evaporative Enhancement of Air-Cooled
Condensers - Measurements at Mammoth
Unit 200 Media Performance Data
3,000
Net Output - kW
2,500
2,000
after Munters
1,500
1,000
before Munters
500
40
45
50
55
60
65
70
75
80
Ambient Temperature °F (@weather station)
Munters increased net power output 62% (800 kW to 1,300 kW
At 78°F ambient
85
Summary of Heat Rejection
R&D Benefits
• Increasing heat transfer on air and tube sides 30%
can reduce electricity cost by 0.5 ¢/kWh
• Evaporative enhancement and trim condenser
concepts can potentially double output of air-cooled
plants on summer days; payback for retrofit can be <
3 years depending on water and electricity costs
Innovative Components - Separators
• Separators disengage solids and liquids from
vapor.
• They may also be used to separate NC gases.
• Poor performance results in costly damage to
turbo-machinery.
• An industry-wide assessment of separators is
needed to reduce O&M costs.
• NREL brings advanced tools such as CFD
(computational fluid dynamics) to industry
• Partnership with Two-Phase Engineering
Well Test Plume Path lines
Separator in Operation
“DIRECT USE” - Applications Other Than
Generating Electricity at Temperatures Under 250°F
•
•
•
•
•
Heating and Cooling
Aquaculture
Industrial Process Heat
Agricultural Process Heat
Spas, Pools and Bathing
Two Activities:
(1)
Direct Use Field Verification Projects
(2)
Direct Use Technical Support, Testing and Evaluation, OIT and WSU
OIT: web hits: 2,000,000+ , in-person or phone assistance requests: 2000+
Direct Use Projects
PROJECT
Location
Phase I
Description
STATUS
SKS
Management
Home Valley,
WA
$75,000
Space heating, water heating
and spa heating for a resort to
be built-out in several phases
Phase I study I progress.
Problem encountered with
drilling an injection well
I’SOT
Canby, CA
$63,800
District and water heating
system project for a complex
of 32 buildings totaling 44,000
sq ft
Phase I study completed.
Environmental Assessment
completed and FONSI received;
Preparing to implement Phase
II
City of Klamath
Falls
Klamath Falls,
OR
$25,300
Expansion of the city’s district
heating system into a new
downtown area and increasing
its efficiency to serve new
customers from the existing
wells
Phase I study being completed;
100% design review for
proposed Phase II project to be
conducted in April
University of
Idaho/Idaho
Water Resources
Research
Institute
Boise, ID
$74,998
Geothermal-driven absorption
cooling system for a new office
building at the University
Phase I study completed.
Geothermal-driven absorption
cooling was found not to be
cost-effective
AmeriCulture
Animas, NM
$75,000
Use of direct use geothermal
system to expand existing
tilapia and add new business
of growing fish to market size
AmeriCulture is seeking
funding mechanism for Phase I
Small Scale Field Verification Plants
• Kalina Cycle – Plant to be built via Exergy
to provide cost and performance data,
support to DOE-GO
• Mixed Working Fluid Binary Plant –
Evaluation underway (Power Engineers) of
a potential plant at Empire to provide cost
and performance data
• DOE assumes a significant portion of the
risk
Geothermal Communications
Objective:
- Educate all stakeholder groups about geothermal energy, and
- Convey the mainstream potential of this exciting technology
Quarterly GRC Bulletin Inserts –
industry audience
Geothermal Today – all audiences
GPW
State Posters
GPW Native American Poster
GPW State Fact Sheets –
GPW stakeholder audience
Web
Sites
Exhibits
and
Displays
NREL ESR&T Summary
• It is Possible to Reduce COE by 1¢/kWh
• Opportunities Exist for Quick Returns, 5 to 7 yrs
to Implementation
• Program is on the Way to Success, ala Direct
Contact Condenser, PPS
• All Activities are in Partnership with Industry
• Proper Technical Areas are Targeted
• Cost-Effective R&D Underway, guided by
Extensive Systems Analyses
• Promoting Direct Use is Important