Thermodynamics Overview

Jasper's thermodynamic engine calculates physical properties required for process simulation.

Capabilities

Property	Method	Status
Heat capacity (Cp)	Polynomial correlation	Implemented
Enthalpy	Integration of Cp	Implemented
Vapor pressure	Antoine equation	Implemented
VLE	Raoult's Law	Implemented
Density	Ideal gas / liquid correlations	Partial

Property Calculation Flow

Component Data (MW, Tc, Pc, Cp coefficients, Antoine coefficients)
         │
         ▼
┌─────────────────┐
│  Heat Capacity  │  →  Cp(T) = a + bT + cT² + dT³
└─────────────────┘
         │
         ▼
┌─────────────────┐
│    Enthalpy     │  →  H(T) = ∫Cp dT + Hf
└─────────────────┘
         │
         ▼
┌─────────────────┐
│ Vapor Pressure  │  →  log(Psat) = A - B/(T+C)
└─────────────────┘
         │
         ▼
┌─────────────────┐
│      VLE        │  →  Ki = Psat,i / P
└─────────────────┘

Property method availability per engine

Each engine supports a different set of property methods. The IDAES column applies when optimization is invoked through the Jasper agent.

Method	Quick	Rigorous (DWSIM)	Optimize (IDAES, via agent)	Best for
Ideal (Raoult's Law)	✓	✓	✓	Ideal mixtures, validation
PR (Peng-Robinson)	✓	✓	✓	General-purpose VLE, hydrocarbons
SRK (Soave-Redlich-Kwong)	—	✓	✓	Hydrocarbons, gas processing
NRTL	✓	✓	✓	Polar / non-ideal liquids
UNIQUAC	—	✓	✓	Strongly non-ideal liquids, LLE
UNIFAC	—	✓	—	Group contribution estimates
eNRTL	—	—	✓	Electrolytes, amines
IAPWS-IF97 (steam)	—	✓	—	Steam cycles, utilities
Electrolytes (DWSIM)	—	✓	—	Aqueous electrolyte systems

For a detailed guide on selecting and configuring property packages, see Property Packages.

Assumptions

Quick mode (when using the Ideal property method specifically):

• Ideal gas behavior for vapor phase
• Ideal liquid solutions (Raoult's Law)
• No solid phases

Quick mode also supports PR and NRTL with full fugacity / activity coefficient calculations — pick those for non-ideal systems before reaching for a backend.

Planned improvements (Quick mode):

• Steam tables (IAPWS-IF97)
• UNIQUAC / UNIFAC
• Henry's Law for dissolved gases

tip

For electrolytes, amines, and steam cycles, use Rigorous mode (DWSIM provides IAPWS-IF97 steam tables and electrolyte property packages). For equation-oriented optimization with eNRTL, ask the agent — it routes through the IDAES backend.

Units

All internal calculations use SI units:

Property	Internal Unit
Temperature	K
Pressure	Pa
Flow	mol/s
Enthalpy	J/mol
Heat capacity	J/(mol·K)