Efficiency Extra Edition
BY TINA TOBUREN, P.E.
Announcements
|
Next LM6000 Seminar
to be held in San Diego, CA – March
11-12, 2010 |
Read & Comment
on Tina’s Blog: |
How to determine Expected Performance
Last year’s newsletter included details relating to Corrected
Performance, so this year, I
thought we’d start out with a discussion of Expected Performance. The story starts out similarly: selecting raw
data, making sure all sensors are calibrated and locations verified to make
sure the point you are recording is indeed the one you want.
If you’ve followed my previous newsletters, you are now trending both
measured and corrected performance (heat rate and output), and can see how
corrected performance points out when maintenance or water washes may be
necessary. But what do you tell your
dispatcher when they ask how much power you can deliver during the next hour or
the next day?
Operators can often answer this question based on their knowledge of the
plant’s past operating history. But for
new operators or periods following maintenance or upgrades, the estimates may
not be accurate enough for your needs.
When relying on personal knowledge of a plant, you may also tend to be
more conservative in your estimate of the expected output the plant can
deliver, which may cost your facility money in lost profits – not only will you
be asked to generate a lesser amount, but your efficiency may suffer by not
operating at full load.
There are a number of different ways to determine the expected performance
of your plant:
1. Statistical regression models: These can be easy to put together, and result
in a fairly good number for expected output and heat rate. But there are some limitations – you normally
have to pick just a single parameter as the explanatory variable (x-axis). This leaves the user to interpret when other
variables are causing changes in performance.
If you pick ambient temperature as the x-axis, you’ll need to scrub the
data to minimize the impact due to changes in humidity, pressure and the status
of any augmentation or inlet cooling equipment you may have (duct burners,
steam injection, SPRINT, chillers, foggers, evap
coolers, etc.).
You also need to be sure to select data only when equipment is operating at
full capacity. For models
built from all available operating data, you may get a result which tells you
what you have been asked to generate
in the past – but not what your plant is actually
capable of doing. This is especially
true for plants that often operate in AGC.
2.
Cycle deck models: (GateCycle, PEPSE,
IPSEPRO, APPS, etc.) While these models can take a lot longer to put together,
they can be more flexible in the result they provide. Once the plant model has been built and
verified, various inputs (ambient conditions, equipment status, etc.) can be
adjusted as needed to determine the expected output and heat rate of the
facility. There are also drawbacks to
this type of model – a lot of information is required to build the initial
model, if built from scratch, and verification can be a time consuming process,
especially if it is desired to “tune” the model to current degradation levels.
3. Spreadsheet
models: For plants with
available engineering expertise, but no cycle deck experience, a spreadsheet
based model may be a good compromise.
Information collected during construction, and often included in plant
acceptance test procedures (including correction curves), can be used to create
an expected performance model within a relatively simple spreadsheet. Statistical analysis can then be used to
verify and/or adjust the design model to fit current levels of equipment
degradation. The spreadsheet models can
get complex, depending on the level of detail desired. Other drawbacks to the spreadsheet models
include the amount of time required to build them and verify the results.
By knowing your expected performance, you can work with
your power marketers to improve your dispatched loads for better productivity
and profitability!
If you need help with your modeling efforts, please contact me!
Seminar: LM6000 Performance Characteristics, Testing
and Long-Term Condition Monitoring
When: March 11 & 12, 2010
Where: The Omni Hotel San Diego, CA
Near the WTUI Venue (see www.wtui.com)
Additional information on
the seminar, including an agenda, can be found on at http://www.t2e3.com/LM6000.php or by
sending an email to seminars@t2e3.com
Register before February 1st to receive a
10% discount off the cost of the seminar.
T2E3
Products & Services
|
Analysis Tools & Models |
Excel Workbooks, Macros & Add-Ins |
Training Seminars |
|
Compressor Efficiency Tracking Software |
Performance Monitoring Program Design,
Support and Evaluation |
Performance Test Design, Direction and
Support |
T2E3 Add-ins
for Excel
Streamline your analysis
spreadsheets by using functions from the T2E3 Automation Add-ins. Available
functions include ASME steam tables, ASHRAE air properties, orifice flow meter
calculations and select performance functions, including: compressor efficiency
and evaporative cooler effectiveness.
For a complete function listing, available options or a trial version of an
add-in contact T2E3 at 425-821-6036
T2E3 Performance
Analysis Services for Power Plants
Including:
Analysis Tools & Software – from customized spreadsheets to add-ins for Excel or
complete compiled programs, T2E3 can develop software tools and analyses to
support all your performance monitoring needs, including integrating your
existing tools with available site data systems, to create online systems
providing data and results in real-time.
Training – both public and private seminars are available. Interactive sessions increase attendees’
knowledge and understanding of the thermodynamic cycles, instrumentation and
analyses needed to improve equipment performance and reliability.
Performance
Test Support – for annual capacity or PPA
performance tests. Support available
includes developing procedures, analyses and reports as well as on-site test
direction.
Performance and Dispatch Models – Support for power marketers
and dispatchers to increase their understanding of the operation of your
facility. Do they constantly dispatch
the plant at loads which are difficult or impossible to maintain? T2E3 can help you build tools and training
programs to help all parties understand the expected changes in performance due
to ambient conditions and operating constraints.
Unlock the potential of your
operation. Call for more information on
how we can work together, today!
T2E3
Tina Toburen’s Energy Efficiency Enterprises
14260 120th PL NE, Kirkland, WA 98034
Phone: 425-821-6036
Fax: 253-550-6992
E-mail: performance@t2e3.com
T2E3 Newsletter Volume 4, Issue 1:
January 2010
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