Advanced Power Plant + Gas Turbines Model Library (APP_Lib_GT)
APP_Lib_GT is a model library for building modular, equation-based performance models of thermal power generation systems—from conventional steam plants to CHP and combined cycles with gas turbines and HRSGs. It supports both design-point sizing and off-design / part-load simulation, enabling fast cycle studies, integration assessments, and realistic operational scenario analysis.
A key design philosophy of APP_Lib_GT is its fine-grained component approach. Instead of relying on a few “monolithic” blocks, the library tends toward smaller, well-defined components (e.g., individual heat-transfer sections, pressure-loss elements, mixing/splitting points, dedicated auxiliary models). This has two practical benefits:
Flexibility without sacrificing detail: Smaller building blocks let you represent real plant layouts more faithfully—especially when you need to capture bypasses, bleed flows, staged heat recovery, recirculation, or non-standard integration points—while still keeping the model structured and readable.
A strong compromise between accuracy and usability: You can start with a straightforward flowsheet using sensible defaults, then increase fidelity selectively where it matters (losses, temperature approach, part-load behavior, auxiliary demand) without turning the model into a one-off custom development.
In practice, this means APP_Lib_GT works well for both rapid concept screening (compare configurations and parameter sets) and engineering-grade refinement (quantify efficiency, losses, and constraints; test improvements; run sensitivities and optimization). The library includes a broad set of ready-to-connect unit models—covering turbomachinery, heat exchangers and heat recovery, combustion, piping/pressure losses, cooling, and auxiliaries—so you can focus on system decisions rather than rebuilding fundamentals.
Available Unit Models
The following unit models are available in the library.
boiler
simple boiler model
combustor_c
combustion chamber, fuel as chemical composition, for gaseous fuels
compressor
compressor
condenser
condenser
connector
connector
deaerator
deaerator
double_htex
heat exchanger with two secondary sides
drum
drum
flash
flash
fuel_analyzer
fuel analyzer which gives detailed information on fuel composition
fuel_mixer
mixer for a fuel_stream
fuel_splitter
splitter for a fuel_stream
gas_analyzer
gas analyzer which gives various information on gas composition
gas_turbine
gas turbine
gear
gears
generator
generator
glipex
gliding pressure extraction
htex
general purpose heat exchanger
htex_co
heat exchanger, cocurrent
htex_condensing
heat exchanger for flue gas condesation
htex_counter
heat exchanger, counter current
htex_evaporator
evaporator with internal circulation
injector
injection cooler
labyrinth
labyrinth gland
mech_loss
mechanical loss
mixer
mixer
motor
motor
gasifier
gasifier for solid and liquid fuels
optimization
optimization element
pipe
pipe
preheater
preheater
preheater2
preheater with cooling zone
preheater3
preheater with steam cooler and condensation zone
pump
pump
reheater
simple reheater model
separator
separator
sink
sink for a stream
source
source for a stream
splitter
splitter
splitter_mixer
compensation pipe
static_head
static head of a fluid
support
supported pressure
triple_htex
heat exchanger with three secondary sides
turbine
turbine
turbine_end
turbine, end stage
valve
valve
xprescription
prescription/calculation of steam quality
ambient_sink
release of a stream at ambient pressure
ambient_source
source for an air stream at ambient conditions
combustor
combustion chamber, fuel composition as elementary analysis, for solid and liquid fuels
combustor_c_rad
combustion chamber, fuel as chemical composition, for gaseous fuels, with radiative heat transfer to heat receiving walls
combustor_rad
combustion chamber, fuel composition as elementary analysis, for solid and liquid fuels, with radiative heat transfer to heat receiving walls and optional grate cooling
conditional_setting
free conditional equation to set selected variables
cooling_tower_dry
dry cooling tower
cooling_tower_wet
wet cooling tower
electrolyzer_PEM
PEM electrolyzer model for hydrogen production
engine
reciprocating engine, fuel composition as elementary analysis
engine_c
reciprocating engine, fuel as chemical composition
free_var
free variable
fuel_sink
sink for a fuel_stream
fuel_source
source for a fuel_stream
fuelcell_PEM
PEM fuel cell model
grate
grate cooler
heat_sink
heat sink
heat_source
heat source
htex_cavity_rad
heat exchanger with combined radiative and convective heat exchange.
htex_wall_rad
heat exchanger with a cooled wall receiving radiative heat
APP_Lib_GT is a model library for building modular, equation-based performance models of thermal power generation systems—from conventional steam plants to CHP and combined cycles with gas turbines and HRSGs. It supports both design-point sizing and off-design / part-load simulation, enabling fast cycle studies, integration assessments, and realistic operational scenario analysis.