# Coolprop DB > Query thermodynamic properties for 100+ fluids from CoolProp database - Skill: `soljourner/coolprop-db` (Agent Skill, multi-file: 3 files) - Install (CLI): `npx skillmds@latest add soljourner/coolprop-db` - Raw SKILL.md: https://api.skillmd.com/api/skills/soljourner/coolprop-db/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: soljourner (https://skillmd.com/u/soljourner) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/soljourner/coolprop-db --- # CoolProp Database Skill Query thermodynamic and transport properties for over 100 pure and pseudo-pure fluids using the CoolProp open-source thermophysical property library. ## Overview CoolProp is a comprehensive thermophysical property database that provides: - **Pure Fluids**: Water, air, ammonia, carbon dioxide, and 100+ others - **Refrigerants**: R134a, R410A, R32, R404A, R407C, R507A, and many more - **Industrial Fluids**: Methane, ethane, propane, butane, nitrogen, oxygen, argon - **Transport Properties**: Viscosity, thermal conductivity, surface tension - **Thermodynamic Properties**: Enthalpy, entropy, density, specific heat - **Phase Information**: Saturation properties, two-phase behavior, critical points CoolProp uses high-accuracy equations of state (Helmholtz energy formulations) and is validated against NIST REFPROP data. ## Installation ### Python ```bash pip install CoolProp ``` ### Verify Installation ```python import CoolProp print(CoolProp.__version__) print(CoolProp.get_global_param_string("version")) ``` ## Core API Functions ### PropsSI - Primary Property Query Function ```python from CoolProp.CoolProp import PropsSI # Syntax: PropsSI(output, input1_name, input1_value, input2_name, input2_value, fluid) value = PropsSI('D', 'T', 298.15, 'P', 101325, 'Water') ``` ### Props1SI - Single Input Properties ```python from CoolProp.CoolProp import Props1SI # For properties requiring only fluid name T_crit = Props1SI('Tcrit', 'Water') # Critical temperature P_crit = Props1SI('Pcrit', 'Water') # Critical pressure ``` ## Property Codes (Input/Output Parameters) ### Thermodynamic Properties | Code | Property | SI Unit | Description | |------|----------|---------|-------------| | `T` | Temperature | K | Absolute temperature | | `P` | Pressure | Pa | Absolute pressure | | `D` | Density | kg/m³ | Mass density | | `H` | Enthalpy | J/kg | Specific enthalpy | | `S` | Entropy | J/kg/K | Specific entropy | | `U` | Internal Energy | J/kg | Specific internal energy | | `Q` | Quality | - | Vapor mass fraction (0-1) | | `Dmolar` | Molar Density | mol/m³ | Molar density | | `Hmolar` | Molar Enthalpy | J/mol | Molar enthalpy | | `Smolar` | Molar Entropy | J/mol/K | Molar entropy | ### Transport Properties | Code | Property | SI Unit | Description | |------|----------|---------|-------------| | `V` | Viscosity | Pa·s | Dynamic viscosity | | `L` | Thermal Conductivity | W/m/K | Thermal conductivity | | `C` | Specific Heat (const P) | J/kg/K | Cp at constant pressure | | `O` | Specific Heat (const V) | J/kg/K | Cv at constant volume | | `PRANDTL` | Prandtl Number | - | Pr = μ·Cp/k | | `I` | Surface Tension | N/m | Liquid-vapor interface | ### Phase Properties | Code | Property | SI Unit | Description | |------|----------|---------|-------------| | `Phase` | Phase Index | - | 0=Liquid, 3=Supercritical, 5=Gas, 6=Two-phase | | `Q` | Quality | - | 0=Saturated liquid, 1=Saturated vapor | ### Critical/Triple Point Properties (Use with Props1SI) | Code | Property | SI Unit | Description | |------|----------|---------|-------------| | `Tcrit` | Critical Temperature | K | Critical point temperature | | `Pcrit` | Critical Pressure | Pa | Critical point pressure | | `Ttriple` | Triple Point Temp | K | Triple point temperature | | `Ptriple` | Triple Point Press | Pa | Triple point pressure | | `M` | Molar Mass | kg/mol | Molecular weight | | `ACENTRIC` | Acentric Factor | - | Pitzer acentric factor | ## Common Fluids ### Water and Air - `Water` - Pure water (H₂O) - `Air` - Dry air (pseudo-pure mixture) ### Common Refrigerants - `R134a` - HFC, common in automotive AC - `R410A` - HFC blend, residential AC/heat pumps - `R32` - HFC, lower GWP alternative - `R404A` - HFC blend, commercial refrigeration - `R407C` - HFC blend, AC systems - `R507A` - HFC blend, low-temperature refrigeration - `R22` - HCFC (being phased out) - `R717` - Ammonia (NH₃) - `R744` - Carbon dioxide (CO₂) ### Hydrocarbons - `Methane`, `Ethane`, `Propane`, `n-Butane`, `IsoButane` - `n-Pentane`, `Isopentane`, `n-Hexane`, `n-Heptane`, `n-Octane` - `n-Nonane`, `n-Decane` ### Cryogenic Gases - `Nitrogen`, `Oxygen`, `Argon`, `Helium`, `Neon`, `Hydrogen` ### Industrial Gases - `CO2` - Carbon dioxide - `CO` - Carbon monoxide - `H2S` - Hydrogen sulfide - `SO2` - Sulfur dioxide - `Ammonia` - NH₃ ## Query Examples ### Example 1: Water Properties at Standard Conditions ```python from CoolProp.CoolProp import PropsSI # Water at 25°C (298.15 K) and 1 atm (101325 Pa) T = 298.15 # K P = 101325 # Pa density = PropsSI('D', 'T', T, 'P', P, 'Water') # kg/m³ enthalpy = PropsSI('H', 'T', T, 'P', P, 'Water') # J/kg entropy = PropsSI('S', 'T', T, 'P', P, 'Water') # J/kg/K viscosity = PropsSI('V', 'T', T, 'P', P, 'Water') # Pa·s cp = PropsSI('C', 'T', T, 'P', P, 'Water') # J/kg/K print(f"Water at {T-273.15}°C and {P/1000:.1f} kPa:") print(f" Density: {density:.2f} kg/m³") print(f" Enthalpy: {enthalpy/1000:.2f} kJ/kg") print(f" Entropy: {entropy/1000:.4f} kJ/kg·K") print(f" Viscosity: {viscosity*1000:.4f} mPa·s") print(f" Cp: {cp/1000:.4f} kJ/kg·K") ``` ### Example 2: Refrigerant Saturation Properties ```python from CoolProp.CoolProp import PropsSI # R134a saturation properties at 25°C T_sat = 298.15 # K fluid = 'R134a' # Get saturation pressure at this temperature P_sat = PropsSI('P', 'T', T_sat, 'Q', 0, fluid) # Pa # Saturated liquid properties (Q=0) rho_liquid = PropsSI('D', 'T', T_sat, 'Q', 0, fluid) h_liquid = PropsSI('H', 'T', T_sat, 'Q', 0, fluid) s_liquid = PropsSI('S', 'T', T_sat, 'Q', 0, fluid) # Saturated vapor properties (Q=1) rho_vapor = PropsSI('D', 'T', T_sat, 'Q', 1, fluid) h_vapor = PropsSI('H', 'T', T_sat, 'Q', 1, fluid) s_vapor = PropsSI('S', 'T', T_sat, 'Q', 1, fluid) # Latent heat h_fg = h_vapor - h_liquid print(f"{fluid} at {T_sat-273.15}°C:") print(f" Saturation pressure: {P_sat/1000:.2f} kPa") print(f" Liquid density: {rho_liquid:.2f} kg/m³") print(f" Vapor density: {rho_vapor:.2f} kg/m³") print(f" Latent heat: {h_fg/1000:.2f} kJ/kg") ``` ### Example 3: Pressure-Enthalpy (P-H) State Point ```python from CoolProp.CoolProp import PropsSI # Find temperature at known pressure and enthalpy P = 500000 # 5 bar = 500 kPa h = 250000 # 250 kJ/kg T = PropsSI('T', 'P', P, 'H', h, 'R134a') Q = PropsSI('Q', 'P', P, 'H', h, 'R134a') print(f"R134a at {P/1000:.0f} kPa and {h/1000:.0f} kJ/kg:") print(f" Temperature: {T-273.15:.2f}°C") print(f" Quality: {Q:.4f} (0=liquid, 1=vapor)") ``` ### Example 4: Critical and Triple Point Data ```python from CoolProp.CoolProp import Props1SI fluids = ['Water', 'CO2', 'Nitrogen', 'R134a'] for fluid in fluids: T_crit = Props1SI('Tcrit', fluid) P_crit = Props1SI('Pcrit', fluid) T_triple = Props1SI('Ttriple', fluid) M = Props1SI('M', fluid) print(f"\n{fluid}:") print(f" Critical point: {T_crit-273.15:.2f}°C, {P_crit/1e6:.2f} MPa") print(f" Triple point: {T_triple-273.15:.2f}°C") print(f" Molar mass: {M*1000:.2f} g/mol") ``` ### Example 5: Viscosity Temperature Dependence ```python from CoolProp.CoolProp import PropsSI import numpy as np # Calculate water viscosity from 0°C to 100°C at atmospheric pressure P = 101325 # Pa temperatures = np.linspace(273.15, 373.15, 11) # 0 to 100°C print("Water viscosity vs temperature:") print("T(°C) μ(mPa·s)") for T in temperatures: mu = PropsSI('V', 'T', T, 'P', P, 'Water') * 1000 # Convert to mPa·s print(f"{T-273.15:5.0f} {mu:.4f}") ``` ### Example 6: Two-Phase Properties ```python from CoolProp.CoolProp import PropsSI # R134a at 10 bar with 50% quality P = 1000000 # 10 bar = 1 MPa Q = 0.5 # 50% vapor T = PropsSI('T', 'P', P, 'Q', Q, 'R134a') h = PropsSI('H', 'P', P, 'Q', Q, 'R134a') s = PropsSI('S', 'P', P, 'Q', Q, 'R134a') rho = PropsSI('D', 'P', P, 'Q', Q, 'R134a') print(f"R134a two-phase at {P/1e6:.1f} MPa, quality = {Q}:") print(f" Temperature: {T-273.15:.2f}°C") print(f" Enthalpy: {h/1000:.2f} kJ/kg") print(f" Entropy: {s/1000:.4f} kJ/kg·K") print(f" Density: {rho:.2f} kg/m³") ``` ## Temperature and Pressure Effects ### Temperature Ranges - Each fluid has valid temperature ranges between triple point and maximum temperature - Typical range: Triple point temperature < T < 2000 K (varies by fluid) - Check limits using `Props1SI('Tmin', fluid)` and `Props1SI('Tmax', fluid)` ### Pressure Ranges - Each fluid has valid pressure ranges - Typical range: Triple point pressure < P < 1000 MPa (varies by fluid) - Check limits using `Props1SI('pmin', fluid)` and `Props1SI('pmax', fluid)` ### Phase Regions 1. **Subcooled Liquid**: T < T_sat at given P, or P > P_sat at given T 2. **Two-Phase**: T = T_sat and 0 < Q < 1 3. **Superheated Vapor**: T > T_sat at given P, or P < P_sat at given T 4. **Supercritical**: T > T_crit and P > P_crit ### Input Pair Restrictions Not all input pairs are valid in all regions: - **(T, P)**: Valid in single-phase regions only (not in two-phase) - **(P, Q)**: Valid for two-phase and saturation (0 ≤ Q ≤ 1) - **(T, Q)**: Valid for two-phase and saturation (0 ≤ Q ≤ 1) - **(P, H)**: Valid in all regions - **(P, S)**: Valid in all regions - **(H, S)**: Valid in all regions (useful for isentropic processes) ## Error Handling ### Common Errors and Solutions **Error: "CoolProp error: [PropsSI] Two saturation inputs are not valid"** - Problem: Trying to use (T, P) in two-phase region - Solution: Use (T, Q) or (P, Q) for two-phase states **Error: "CoolProp error: Value is outside range"** - Problem: Temperature or pressure outside valid range - Solution: Check fluid limits with Props1SI('Tmin', fluid), etc. **Error: "CoolProp error: Fluid not found"** - Problem: Incorrect fluid name or spelling - Solution: Use exact fluid names (case-sensitive), check documentation **Error: "Unable to match the inputs"** - Problem: Invalid input combination or iteration failed - Solution: Check that input values are physically reasonable ### Safe Query Pattern ```python from CoolProp.CoolProp import PropsSI def safe_props(output, input1, value1, input2, value2, fluid): """Query CoolProp with error handling""" try: result = PropsSI(output, input1, value1, input2, value2, fluid) return result except ValueError as e: print(f"Error querying {fluid}: {e}") return None except Exception as e: print(f"Unexpected error: {e}") return None # Usage density = safe_props('D', 'T', 300, 'P', 101325, 'Water') if density is not None: print(f"Density: {density:.2f} kg/m³") ``` ## Engineering Applications ### HVAC System Design - Refrigerant cycle analysis (evaporator, condenser, compressor, expansion) - Heat exchanger calculations - Coefficient of performance (COP) calculations ### Power Cycles - Rankine cycle (steam turbines) - Brayton cycle (gas turbines) - Organic Rankine Cycle (ORC) ### Process Engineering - Heat transfer calculations - Pipe flow and pressure drop - Phase equilibrium - Storage tank design ### Cryogenic Systems - Liquefaction processes - Storage and handling - Heat leak calculations ## References ### Official Documentation - **CoolProp Website**: http://www.coolprop.org/ - **Python Documentation**: http://www.coolprop.org/coolprop/HighLevelAPI.html - **Fluid Properties**: http://www.coolprop.org/fluid_properties/PurePseudoPure.html - **Validation Data**: http://www.coolprop.org/validation/index.html ### Key Papers - Bell, I. H., Wronski, J., Quoilin, S., & Lemort, V. (2014). "Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp." *Industrial & Engineering Chemistry Research*, 53(6), 2498-2508. ### Equation of State References - Lemmon, E. W., Huber, M. L., & McLinden, M. O. (2013). NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties (REFPROP), Version 9.1. National Institute of Standards and Technology. ### Source Code - **GitHub**: https://github.com/CoolProp/CoolProp - **Issue Tracker**: https://github.com/CoolProp/CoolProp/issues ## Best Practices 1. **Always use SI units** for inputs and outputs (K, Pa, J/kg, etc.) 2. **Check phase regions** before choosing input pairs 3. **Handle errors** gracefully with try-except blocks 4. **Validate ranges** before querying (especially temperature and pressure) 5. **Use quality (Q)** for two-phase calculations 6. **Cache critical properties** if querying multiple times 7. **Use Props1SI** for fluid-only properties (critical points, molar mass) 8. **Prefer (P, H) or (P, S)** for robust queries across all phase regions ## Quick Reference Table | Task | Function | Example | |------|----------|---------| | Two-input property | `PropsSI(output, in1, val1, in2, val2, fluid)` | `PropsSI('D', 'T', 300, 'P', 101325, 'Water')` | | Single-input property | `Props1SI(param, fluid)` | `Props1SI('Tcrit', 'Water')` | | Saturation liquid | Use Q=0 | `PropsSI('H', 'T', 300, 'Q', 0, 'R134a')` | | Saturation vapor | Use Q=1 | `PropsSI('H', 'T', 300, 'Q', 1, 'R134a')` | | Two-phase | Use 0