EXERGY
Real-time Efficiency Analysis for Power Stations
The issue
• You need the ability to detect and diagnose
efficiency problems in a thermal power station.
• You need your operators to be able to react to
the diagnoses and restore the unit to a higher
efficiency.
• This can add significantly to the operational
profits of the station and result in lower CO2
emissions.
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EXERGY
Real-time Efficiency analysis
Less Fuel = Less CO2 = More profit
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What is EXERGY?
EXERGY is a tool for detecting and diagnosing
efficiency problems in thermodynamic
processes
EXERGY saves operating costs. It has a unique
ability to detect problems, diagnose causes and
recommend remedial actions. It also allows
operators to prioritise problems by providing an
estimated cost per hour of the problem.
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What is EXERGY?
• EXERGY is the ONLY software available for continuous
efficiency monitoring that is based on sound physics.
• EXERGY gives you continuous online efficiency
monitoring
• EXERGY lets you pinpoint efficiency losses
• EXERGY delivers instant reporting and diagnostics
• EXERGY finds the root cause of problems, automatically
• EXERGY is the only software that calculates 2nd Law
efficiency for your power station processes. It allows
trending of component efficiencies and drill-downs to
locate sources of problems .
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How EXERGY works: Background
• Plant efficiency management in the first instance is
concerned with the Heat Rate, a 1st Law measure of
efficiency.
• Ultimately a plant wants to produce as much output for
the least expenditure of fuel.
• When plant efficiency deteriorates, either through
incorrect operation, sudden failure in a component or
through gradual loss of condition, the challenge is to find
the cause and then cost the value of repairs.
• 1st Law measures of component efficiency are not useful
for this analysis.
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How EXERGY works: Background
• In contrast, 2nd efficiency measures are ideally
suited for this task.
• Exergy (availability) losses are additive (i.e. the
total exergy loss for the plant is the sum of all
the component losses), enabling attribution of
the losses to plant components.
• The plant is modelled as a hierarchy of
components, starting with entire plant. Losses
can be tracked from top level of the plant to
individual components.
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How EXERGY works: Background
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Entropy is additive
Entropy (and Exergy) is not a conserved quantity
Unit heatrate trend correlates exactly with Exergy loss
trend
These properties enable a quantitative method for
determining the root cause of heat rate excursions.
The resultant diagnostics procedure is valid both for
short term ( real time) and long term.
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Thermal Plant Efficiency
• The plant state at commissioning should be optimal
• Variance from optimal due to:
– Gradual deterioration of components
– Failure of components
– Sub-optimal/incorrect operation
• EXERGY detects the root cause of any efficiency loss.
• Alarms when efficiency excursions occur with operating
recommendations
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EXERGY alarms
• Efficiency excursions result in alarms
• Alarms go to:
– Email if desired.
– Client PCs
– A central database
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Example Exergy alarm
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Exergy Alarm Analysis
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An example EXERGY audit: Bayeswater Station, NSW
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EXERGY audit as it happened, Bayeswater
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Exergy audit as it happened, Bayeswater
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Real Measurements, Bayeswater
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Overview of Exergy Components
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EXERGY installation
• Installs on MS Windows Server
• Interfaces with OsiSoft PI
– But custom interfaces can be used instead
– Reads instrumentation & writes back results
• Communicates with clients over TCP/IP network
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Contact us
• exergy@gns.cri.nz
• www.powerstationefficiency.com
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