“The universe cannot be read until we have learned the language… It is written in mathematical language, and the letters are triangles, circles and other geometrical figures… Without these, one is wandering about in a dark labyrinth.”
— Galileo Galilei (1564–1642)
Overview
This note documents a compact Visual Basic application I built to perform thermodynamic performance analysis and simple optimization for a small-scale coal-fired steam power plant (CFSPP). The goal: provide engineers with a fast, transparent calculator that mirrors the way we think in a single-line heat-balance diagram, not a black box.
Model and Methods
- Working fluid: water/steam properties from IAPWS-IF97 (Industrial Formulation, 1997).
- Cycle blocks: boiler, superheater, HP/LP turbines, reheater (optional), deaerator, condensate and feedwater heaters, condenser, and auxiliary drives.
- Core calculations: enthalpy/entropy states, mass & energy balances, component efficiencies (η_boiler, η_turbine_HP/LP, η_generator, η_pumps, η_pipe), and steam-flow splits.
- KPIs reported:
- Gross / Net Power (kW)
- Heat Rate – GPHR/NPHR (kCal/kWh)
- Coal Specific Consumption (kg/kWh)
- Cycle efficiency (thermal and net)
- Major loss accounting (stack, condenser, unaccounted)
- Inputs (left panel): pressures, temperatures, extraction fractions, isentropic efficiencies, auxiliary loads, and assumed losses.
- Outputs (right panel): steam flows per branch (t/h), node enthalpies (kJ/kg), bus-level power, and performance KPIs.
- Results are rendered back onto the diagram so each edit shows an immediate thermodynamic consequence.
- Lightweight, fast to deploy on older Windows workstations in plants.
- GUI-first; operators/engineers can type, run, and see without scripting.
- Easy to lock assumptions and export snapshots for MoM/commissioning records.
- Property calls checked against IF97 tables; cycle results cross-checked with vendor heat balances and plant DCS snapshots.
- Typical deviations: ±0.5–1.5% on key KPIs when inputs are aligned (measurement uncertainty dominates).
- Quick what-if studies: turbine efficiency drift, condenser back-pressure rise, auxiliary load spikes.
- Operator training: link a number change to a physical effect on the heat balance.
- Pre-audit before deeper load-flow or CFD work.
- Lumped-parameter cycle (no detailed fouling/part-load curves unless supplied).
- No combustion chemistry breakdown beyond assumed boiler efficiency.
- Not a relay-level protection or dynamic stability tool—thermo balance first, transients second.
Closing
In Galileo’s spirit, this tool treats the plant as a geometric and numerical language—nodes, lines, and balances. Read the cycle in that language, and the labyrinth becomes a map.